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1
+ """A functions module, includes all the standard functions.
2
+
3
+ Combinatorial - factorial, fibonacci, harmonic, bernoulli...
4
+ Elementary - hyperbolic, trigonometric, exponential, floor and ceiling, sqrt...
5
+ Special - gamma, zeta,spherical harmonics...
6
+ """
7
+
8
+ from sympy.functions.combinatorial.factorials import (factorial, factorial2,
9
+ rf, ff, binomial, RisingFactorial, FallingFactorial, subfactorial)
10
+ from sympy.functions.combinatorial.numbers import (carmichael, fibonacci, lucas, tribonacci,
11
+ harmonic, bernoulli, bell, euler, catalan, genocchi, andre, partition, motzkin)
12
+ from sympy.functions.elementary.miscellaneous import (sqrt, root, Min, Max,
13
+ Id, real_root, cbrt, Rem)
14
+ from sympy.functions.elementary.complexes import (re, im, sign, Abs,
15
+ conjugate, arg, polar_lift, periodic_argument, unbranched_argument,
16
+ principal_branch, transpose, adjoint, polarify, unpolarify)
17
+ from sympy.functions.elementary.trigonometric import (sin, cos, tan,
18
+ sec, csc, cot, sinc, asin, acos, atan, asec, acsc, acot, atan2)
19
+ from sympy.functions.elementary.exponential import (exp_polar, exp, log,
20
+ LambertW)
21
+ from sympy.functions.elementary.hyperbolic import (sinh, cosh, tanh, coth,
22
+ sech, csch, asinh, acosh, atanh, acoth, asech, acsch)
23
+ from sympy.functions.elementary.integers import floor, ceiling, frac
24
+ from sympy.functions.elementary.piecewise import (Piecewise, piecewise_fold,
25
+ piecewise_exclusive)
26
+ from sympy.functions.special.error_functions import (erf, erfc, erfi, erf2,
27
+ erfinv, erfcinv, erf2inv, Ei, expint, E1, li, Li, Si, Ci, Shi, Chi,
28
+ fresnels, fresnelc)
29
+ from sympy.functions.special.gamma_functions import (gamma, lowergamma,
30
+ uppergamma, polygamma, loggamma, digamma, trigamma, multigamma)
31
+ from sympy.functions.special.zeta_functions import (dirichlet_eta, zeta,
32
+ lerchphi, polylog, stieltjes, riemann_xi)
33
+ from sympy.functions.special.tensor_functions import (Eijk, LeviCivita,
34
+ KroneckerDelta)
35
+ from sympy.functions.special.singularity_functions import SingularityFunction
36
+ from sympy.functions.special.delta_functions import DiracDelta, Heaviside
37
+ from sympy.functions.special.bsplines import bspline_basis, bspline_basis_set, interpolating_spline
38
+ from sympy.functions.special.bessel import (besselj, bessely, besseli, besselk,
39
+ hankel1, hankel2, jn, yn, jn_zeros, hn1, hn2, airyai, airybi, airyaiprime, airybiprime, marcumq)
40
+ from sympy.functions.special.hyper import hyper, meijerg, appellf1
41
+ from sympy.functions.special.polynomials import (legendre, assoc_legendre,
42
+ hermite, hermite_prob, chebyshevt, chebyshevu, chebyshevu_root,
43
+ chebyshevt_root, laguerre, assoc_laguerre, gegenbauer, jacobi, jacobi_normalized)
44
+ from sympy.functions.special.spherical_harmonics import Ynm, Ynm_c, Znm
45
+ from sympy.functions.special.elliptic_integrals import (elliptic_k,
46
+ elliptic_f, elliptic_e, elliptic_pi)
47
+ from sympy.functions.special.beta_functions import beta, betainc, betainc_regularized
48
+ from sympy.functions.special.mathieu_functions import (mathieus, mathieuc,
49
+ mathieusprime, mathieucprime)
50
+ ln = log
51
+
52
+ __all__ = [
53
+ 'factorial', 'factorial2', 'rf', 'ff', 'binomial', 'RisingFactorial',
54
+ 'FallingFactorial', 'subfactorial',
55
+
56
+ 'carmichael', 'fibonacci', 'lucas', 'motzkin', 'tribonacci', 'harmonic',
57
+ 'bernoulli', 'bell', 'euler', 'catalan', 'genocchi', 'andre', 'partition',
58
+
59
+ 'sqrt', 'root', 'Min', 'Max', 'Id', 'real_root', 'cbrt', 'Rem',
60
+
61
+ 're', 'im', 'sign', 'Abs', 'conjugate', 'arg', 'polar_lift',
62
+ 'periodic_argument', 'unbranched_argument', 'principal_branch',
63
+ 'transpose', 'adjoint', 'polarify', 'unpolarify',
64
+
65
+ 'sin', 'cos', 'tan', 'sec', 'csc', 'cot', 'sinc', 'asin', 'acos', 'atan',
66
+ 'asec', 'acsc', 'acot', 'atan2',
67
+
68
+ 'exp_polar', 'exp', 'ln', 'log', 'LambertW',
69
+
70
+ 'sinh', 'cosh', 'tanh', 'coth', 'sech', 'csch', 'asinh', 'acosh', 'atanh',
71
+ 'acoth', 'asech', 'acsch',
72
+
73
+ 'floor', 'ceiling', 'frac',
74
+
75
+ 'Piecewise', 'piecewise_fold', 'piecewise_exclusive',
76
+
77
+ 'erf', 'erfc', 'erfi', 'erf2', 'erfinv', 'erfcinv', 'erf2inv', 'Ei',
78
+ 'expint', 'E1', 'li', 'Li', 'Si', 'Ci', 'Shi', 'Chi', 'fresnels',
79
+ 'fresnelc',
80
+
81
+ 'gamma', 'lowergamma', 'uppergamma', 'polygamma', 'loggamma', 'digamma',
82
+ 'trigamma', 'multigamma',
83
+
84
+ 'dirichlet_eta', 'zeta', 'lerchphi', 'polylog', 'stieltjes', 'riemann_xi',
85
+
86
+ 'Eijk', 'LeviCivita', 'KroneckerDelta',
87
+
88
+ 'SingularityFunction',
89
+
90
+ 'DiracDelta', 'Heaviside',
91
+
92
+ 'bspline_basis', 'bspline_basis_set', 'interpolating_spline',
93
+
94
+ 'besselj', 'bessely', 'besseli', 'besselk', 'hankel1', 'hankel2', 'jn',
95
+ 'yn', 'jn_zeros', 'hn1', 'hn2', 'airyai', 'airybi', 'airyaiprime',
96
+ 'airybiprime', 'marcumq',
97
+
98
+ 'hyper', 'meijerg', 'appellf1',
99
+
100
+ 'legendre', 'assoc_legendre', 'hermite', 'hermite_prob', 'chebyshevt',
101
+ 'chebyshevu', 'chebyshevu_root', 'chebyshevt_root', 'laguerre',
102
+ 'assoc_laguerre', 'gegenbauer', 'jacobi', 'jacobi_normalized',
103
+
104
+ 'Ynm', 'Ynm_c', 'Znm',
105
+
106
+ 'elliptic_k', 'elliptic_f', 'elliptic_e', 'elliptic_pi',
107
+
108
+ 'beta', 'betainc', 'betainc_regularized',
109
+
110
+ 'mathieus', 'mathieuc', 'mathieusprime', 'mathieucprime',
111
+ ]
venv/lib/python3.10/site-packages/sympy/functions/__pycache__/__init__.cpython-310.pyc ADDED
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venv/lib/python3.10/site-packages/sympy/functions/combinatorial/__init__.py ADDED
@@ -0,0 +1 @@
 
 
1
+ # Stub __init__.py for sympy.functions.combinatorial
venv/lib/python3.10/site-packages/sympy/functions/combinatorial/__pycache__/__init__.cpython-310.pyc ADDED
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venv/lib/python3.10/site-packages/sympy/functions/combinatorial/__pycache__/factorials.cpython-310.pyc ADDED
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venv/lib/python3.10/site-packages/sympy/functions/combinatorial/__pycache__/numbers.cpython-310.pyc ADDED
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venv/lib/python3.10/site-packages/sympy/functions/combinatorial/factorials.py ADDED
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1
+ from __future__ import annotations
2
+ from functools import reduce
3
+
4
+ from sympy.core import S, sympify, Dummy, Mod
5
+ from sympy.core.cache import cacheit
6
+ from sympy.core.function import Function, ArgumentIndexError, PoleError
7
+ from sympy.core.logic import fuzzy_and
8
+ from sympy.core.numbers import Integer, pi, I
9
+ from sympy.core.relational import Eq
10
+ from sympy.external.gmpy import HAS_GMPY, gmpy
11
+ from sympy.ntheory import sieve
12
+ from sympy.polys.polytools import Poly
13
+
14
+ from math import factorial as _factorial, prod, sqrt as _sqrt
15
+
16
+ class CombinatorialFunction(Function):
17
+ """Base class for combinatorial functions. """
18
+
19
+ def _eval_simplify(self, **kwargs):
20
+ from sympy.simplify.combsimp import combsimp
21
+ # combinatorial function with non-integer arguments is
22
+ # automatically passed to gammasimp
23
+ expr = combsimp(self)
24
+ measure = kwargs['measure']
25
+ if measure(expr) <= kwargs['ratio']*measure(self):
26
+ return expr
27
+ return self
28
+
29
+
30
+ ###############################################################################
31
+ ######################## FACTORIAL and MULTI-FACTORIAL ########################
32
+ ###############################################################################
33
+
34
+
35
+ class factorial(CombinatorialFunction):
36
+ r"""Implementation of factorial function over nonnegative integers.
37
+ By convention (consistent with the gamma function and the binomial
38
+ coefficients), factorial of a negative integer is complex infinity.
39
+
40
+ The factorial is very important in combinatorics where it gives
41
+ the number of ways in which `n` objects can be permuted. It also
42
+ arises in calculus, probability, number theory, etc.
43
+
44
+ There is strict relation of factorial with gamma function. In
45
+ fact `n! = gamma(n+1)` for nonnegative integers. Rewrite of this
46
+ kind is very useful in case of combinatorial simplification.
47
+
48
+ Computation of the factorial is done using two algorithms. For
49
+ small arguments a precomputed look up table is used. However for bigger
50
+ input algorithm Prime-Swing is used. It is the fastest algorithm
51
+ known and computes `n!` via prime factorization of special class
52
+ of numbers, called here the 'Swing Numbers'.
53
+
54
+ Examples
55
+ ========
56
+
57
+ >>> from sympy import Symbol, factorial, S
58
+ >>> n = Symbol('n', integer=True)
59
+
60
+ >>> factorial(0)
61
+ 1
62
+
63
+ >>> factorial(7)
64
+ 5040
65
+
66
+ >>> factorial(-2)
67
+ zoo
68
+
69
+ >>> factorial(n)
70
+ factorial(n)
71
+
72
+ >>> factorial(2*n)
73
+ factorial(2*n)
74
+
75
+ >>> factorial(S(1)/2)
76
+ factorial(1/2)
77
+
78
+ See Also
79
+ ========
80
+
81
+ factorial2, RisingFactorial, FallingFactorial
82
+ """
83
+
84
+ def fdiff(self, argindex=1):
85
+ from sympy.functions.special.gamma_functions import (gamma, polygamma)
86
+ if argindex == 1:
87
+ return gamma(self.args[0] + 1)*polygamma(0, self.args[0] + 1)
88
+ else:
89
+ raise ArgumentIndexError(self, argindex)
90
+
91
+ _small_swing = [
92
+ 1, 1, 1, 3, 3, 15, 5, 35, 35, 315, 63, 693, 231, 3003, 429, 6435, 6435, 109395,
93
+ 12155, 230945, 46189, 969969, 88179, 2028117, 676039, 16900975, 1300075,
94
+ 35102025, 5014575, 145422675, 9694845, 300540195, 300540195
95
+ ]
96
+
97
+ _small_factorials: list[int] = []
98
+
99
+ @classmethod
100
+ def _swing(cls, n):
101
+ if n < 33:
102
+ return cls._small_swing[n]
103
+ else:
104
+ N, primes = int(_sqrt(n)), []
105
+
106
+ for prime in sieve.primerange(3, N + 1):
107
+ p, q = 1, n
108
+
109
+ while True:
110
+ q //= prime
111
+
112
+ if q > 0:
113
+ if q & 1 == 1:
114
+ p *= prime
115
+ else:
116
+ break
117
+
118
+ if p > 1:
119
+ primes.append(p)
120
+
121
+ for prime in sieve.primerange(N + 1, n//3 + 1):
122
+ if (n // prime) & 1 == 1:
123
+ primes.append(prime)
124
+
125
+ L_product = prod(sieve.primerange(n//2 + 1, n + 1))
126
+ R_product = prod(primes)
127
+
128
+ return L_product*R_product
129
+
130
+ @classmethod
131
+ def _recursive(cls, n):
132
+ if n < 2:
133
+ return 1
134
+ else:
135
+ return (cls._recursive(n//2)**2)*cls._swing(n)
136
+
137
+ @classmethod
138
+ def eval(cls, n):
139
+ n = sympify(n)
140
+
141
+ if n.is_Number:
142
+ if n.is_zero:
143
+ return S.One
144
+ elif n is S.Infinity:
145
+ return S.Infinity
146
+ elif n.is_Integer:
147
+ if n.is_negative:
148
+ return S.ComplexInfinity
149
+ else:
150
+ n = n.p
151
+
152
+ if n < 20:
153
+ if not cls._small_factorials:
154
+ result = 1
155
+ for i in range(1, 20):
156
+ result *= i
157
+ cls._small_factorials.append(result)
158
+ result = cls._small_factorials[n-1]
159
+
160
+ # GMPY factorial is faster, use it when available
161
+ elif HAS_GMPY:
162
+ result = gmpy.fac(n)
163
+
164
+ else:
165
+ bits = bin(n).count('1')
166
+ result = cls._recursive(n)*2**(n - bits)
167
+
168
+ return Integer(result)
169
+
170
+ def _facmod(self, n, q):
171
+ res, N = 1, int(_sqrt(n))
172
+
173
+ # Exponent of prime p in n! is e_p(n) = [n/p] + [n/p**2] + ...
174
+ # for p > sqrt(n), e_p(n) < sqrt(n), the primes with [n/p] = m,
175
+ # occur consecutively and are grouped together in pw[m] for
176
+ # simultaneous exponentiation at a later stage
177
+ pw = [1]*N
178
+
179
+ m = 2 # to initialize the if condition below
180
+ for prime in sieve.primerange(2, n + 1):
181
+ if m > 1:
182
+ m, y = 0, n // prime
183
+ while y:
184
+ m += y
185
+ y //= prime
186
+ if m < N:
187
+ pw[m] = pw[m]*prime % q
188
+ else:
189
+ res = res*pow(prime, m, q) % q
190
+
191
+ for ex, bs in enumerate(pw):
192
+ if ex == 0 or bs == 1:
193
+ continue
194
+ if bs == 0:
195
+ return 0
196
+ res = res*pow(bs, ex, q) % q
197
+
198
+ return res
199
+
200
+ def _eval_Mod(self, q):
201
+ n = self.args[0]
202
+ if n.is_integer and n.is_nonnegative and q.is_integer:
203
+ aq = abs(q)
204
+ d = aq - n
205
+ if d.is_nonpositive:
206
+ return S.Zero
207
+ else:
208
+ isprime = aq.is_prime
209
+ if d == 1:
210
+ # Apply Wilson's theorem (if a natural number n > 1
211
+ # is a prime number, then (n-1)! = -1 mod n) and
212
+ # its inverse (if n > 4 is a composite number, then
213
+ # (n-1)! = 0 mod n)
214
+ if isprime:
215
+ return -1 % q
216
+ elif isprime is False and (aq - 6).is_nonnegative:
217
+ return S.Zero
218
+ elif n.is_Integer and q.is_Integer:
219
+ n, d, aq = map(int, (n, d, aq))
220
+ if isprime and (d - 1 < n):
221
+ fc = self._facmod(d - 1, aq)
222
+ fc = pow(fc, aq - 2, aq)
223
+ if d%2:
224
+ fc = -fc
225
+ else:
226
+ fc = self._facmod(n, aq)
227
+
228
+ return fc % q
229
+
230
+ def _eval_rewrite_as_gamma(self, n, piecewise=True, **kwargs):
231
+ from sympy.functions.special.gamma_functions import gamma
232
+ return gamma(n + 1)
233
+
234
+ def _eval_rewrite_as_Product(self, n, **kwargs):
235
+ from sympy.concrete.products import Product
236
+ if n.is_nonnegative and n.is_integer:
237
+ i = Dummy('i', integer=True)
238
+ return Product(i, (i, 1, n))
239
+
240
+ def _eval_is_integer(self):
241
+ if self.args[0].is_integer and self.args[0].is_nonnegative:
242
+ return True
243
+
244
+ def _eval_is_positive(self):
245
+ if self.args[0].is_integer and self.args[0].is_nonnegative:
246
+ return True
247
+
248
+ def _eval_is_even(self):
249
+ x = self.args[0]
250
+ if x.is_integer and x.is_nonnegative:
251
+ return (x - 2).is_nonnegative
252
+
253
+ def _eval_is_composite(self):
254
+ x = self.args[0]
255
+ if x.is_integer and x.is_nonnegative:
256
+ return (x - 3).is_nonnegative
257
+
258
+ def _eval_is_real(self):
259
+ x = self.args[0]
260
+ if x.is_nonnegative or x.is_noninteger:
261
+ return True
262
+
263
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
264
+ arg = self.args[0].as_leading_term(x)
265
+ arg0 = arg.subs(x, 0)
266
+ if arg0.is_zero:
267
+ return S.One
268
+ elif not arg0.is_infinite:
269
+ return self.func(arg)
270
+ raise PoleError("Cannot expand %s around 0" % (self))
271
+
272
+ class MultiFactorial(CombinatorialFunction):
273
+ pass
274
+
275
+
276
+ class subfactorial(CombinatorialFunction):
277
+ r"""The subfactorial counts the derangements of $n$ items and is
278
+ defined for non-negative integers as:
279
+
280
+ .. math:: !n = \begin{cases} 1 & n = 0 \\ 0 & n = 1 \\
281
+ (n-1)(!(n-1) + !(n-2)) & n > 1 \end{cases}
282
+
283
+ It can also be written as ``int(round(n!/exp(1)))`` but the
284
+ recursive definition with caching is implemented for this function.
285
+
286
+ An interesting analytic expression is the following [2]_
287
+
288
+ .. math:: !x = \Gamma(x + 1, -1)/e
289
+
290
+ which is valid for non-negative integers `x`. The above formula
291
+ is not very useful in case of non-integers. `\Gamma(x + 1, -1)` is
292
+ single-valued only for integral arguments `x`, elsewhere on the positive
293
+ real axis it has an infinite number of branches none of which are real.
294
+
295
+ References
296
+ ==========
297
+
298
+ .. [1] https://en.wikipedia.org/wiki/Subfactorial
299
+ .. [2] https://mathworld.wolfram.com/Subfactorial.html
300
+
301
+ Examples
302
+ ========
303
+
304
+ >>> from sympy import subfactorial
305
+ >>> from sympy.abc import n
306
+ >>> subfactorial(n + 1)
307
+ subfactorial(n + 1)
308
+ >>> subfactorial(5)
309
+ 44
310
+
311
+ See Also
312
+ ========
313
+
314
+ factorial, uppergamma,
315
+ sympy.utilities.iterables.generate_derangements
316
+ """
317
+
318
+ @classmethod
319
+ @cacheit
320
+ def _eval(self, n):
321
+ if not n:
322
+ return S.One
323
+ elif n == 1:
324
+ return S.Zero
325
+ else:
326
+ z1, z2 = 1, 0
327
+ for i in range(2, n + 1):
328
+ z1, z2 = z2, (i - 1)*(z2 + z1)
329
+ return z2
330
+
331
+ @classmethod
332
+ def eval(cls, arg):
333
+ if arg.is_Number:
334
+ if arg.is_Integer and arg.is_nonnegative:
335
+ return cls._eval(arg)
336
+ elif arg is S.NaN:
337
+ return S.NaN
338
+ elif arg is S.Infinity:
339
+ return S.Infinity
340
+
341
+ def _eval_is_even(self):
342
+ if self.args[0].is_odd and self.args[0].is_nonnegative:
343
+ return True
344
+
345
+ def _eval_is_integer(self):
346
+ if self.args[0].is_integer and self.args[0].is_nonnegative:
347
+ return True
348
+
349
+ def _eval_rewrite_as_factorial(self, arg, **kwargs):
350
+ from sympy.concrete.summations import summation
351
+ i = Dummy('i')
352
+ f = S.NegativeOne**i / factorial(i)
353
+ return factorial(arg) * summation(f, (i, 0, arg))
354
+
355
+ def _eval_rewrite_as_gamma(self, arg, piecewise=True, **kwargs):
356
+ from sympy.functions.elementary.exponential import exp
357
+ from sympy.functions.special.gamma_functions import (gamma, lowergamma)
358
+ return (S.NegativeOne**(arg + 1)*exp(-I*pi*arg)*lowergamma(arg + 1, -1)
359
+ + gamma(arg + 1))*exp(-1)
360
+
361
+ def _eval_rewrite_as_uppergamma(self, arg, **kwargs):
362
+ from sympy.functions.special.gamma_functions import uppergamma
363
+ return uppergamma(arg + 1, -1)/S.Exp1
364
+
365
+ def _eval_is_nonnegative(self):
366
+ if self.args[0].is_integer and self.args[0].is_nonnegative:
367
+ return True
368
+
369
+ def _eval_is_odd(self):
370
+ if self.args[0].is_even and self.args[0].is_nonnegative:
371
+ return True
372
+
373
+
374
+ class factorial2(CombinatorialFunction):
375
+ r"""The double factorial `n!!`, not to be confused with `(n!)!`
376
+
377
+ The double factorial is defined for nonnegative integers and for odd
378
+ negative integers as:
379
+
380
+ .. math:: n!! = \begin{cases} 1 & n = 0 \\
381
+ n(n-2)(n-4) \cdots 1 & n\ \text{positive odd} \\
382
+ n(n-2)(n-4) \cdots 2 & n\ \text{positive even} \\
383
+ (n+2)!!/(n+2) & n\ \text{negative odd} \end{cases}
384
+
385
+ References
386
+ ==========
387
+
388
+ .. [1] https://en.wikipedia.org/wiki/Double_factorial
389
+
390
+ Examples
391
+ ========
392
+
393
+ >>> from sympy import factorial2, var
394
+ >>> n = var('n')
395
+ >>> n
396
+ n
397
+ >>> factorial2(n + 1)
398
+ factorial2(n + 1)
399
+ >>> factorial2(5)
400
+ 15
401
+ >>> factorial2(-1)
402
+ 1
403
+ >>> factorial2(-5)
404
+ 1/3
405
+
406
+ See Also
407
+ ========
408
+
409
+ factorial, RisingFactorial, FallingFactorial
410
+ """
411
+
412
+ @classmethod
413
+ def eval(cls, arg):
414
+ # TODO: extend this to complex numbers?
415
+
416
+ if arg.is_Number:
417
+ if not arg.is_Integer:
418
+ raise ValueError("argument must be nonnegative integer "
419
+ "or negative odd integer")
420
+
421
+ # This implementation is faster than the recursive one
422
+ # It also avoids "maximum recursion depth exceeded" runtime error
423
+ if arg.is_nonnegative:
424
+ if arg.is_even:
425
+ k = arg / 2
426
+ return 2**k * factorial(k)
427
+ return factorial(arg) / factorial2(arg - 1)
428
+
429
+
430
+ if arg.is_odd:
431
+ return arg*(S.NegativeOne)**((1 - arg)/2) / factorial2(-arg)
432
+ raise ValueError("argument must be nonnegative integer "
433
+ "or negative odd integer")
434
+
435
+
436
+ def _eval_is_even(self):
437
+ # Double factorial is even for every positive even input
438
+ n = self.args[0]
439
+ if n.is_integer:
440
+ if n.is_odd:
441
+ return False
442
+ if n.is_even:
443
+ if n.is_positive:
444
+ return True
445
+ if n.is_zero:
446
+ return False
447
+
448
+ def _eval_is_integer(self):
449
+ # Double factorial is an integer for every nonnegative input, and for
450
+ # -1 and -3
451
+ n = self.args[0]
452
+ if n.is_integer:
453
+ if (n + 1).is_nonnegative:
454
+ return True
455
+ if n.is_odd:
456
+ return (n + 3).is_nonnegative
457
+
458
+ def _eval_is_odd(self):
459
+ # Double factorial is odd for every odd input not smaller than -3, and
460
+ # for 0
461
+ n = self.args[0]
462
+ if n.is_odd:
463
+ return (n + 3).is_nonnegative
464
+ if n.is_even:
465
+ if n.is_positive:
466
+ return False
467
+ if n.is_zero:
468
+ return True
469
+
470
+ def _eval_is_positive(self):
471
+ # Double factorial is positive for every nonnegative input, and for
472
+ # every odd negative input which is of the form -1-4k for an
473
+ # nonnegative integer k
474
+ n = self.args[0]
475
+ if n.is_integer:
476
+ if (n + 1).is_nonnegative:
477
+ return True
478
+ if n.is_odd:
479
+ return ((n + 1) / 2).is_even
480
+
481
+ def _eval_rewrite_as_gamma(self, n, piecewise=True, **kwargs):
482
+ from sympy.functions.elementary.miscellaneous import sqrt
483
+ from sympy.functions.elementary.piecewise import Piecewise
484
+ from sympy.functions.special.gamma_functions import gamma
485
+ return 2**(n/2)*gamma(n/2 + 1) * Piecewise((1, Eq(Mod(n, 2), 0)),
486
+ (sqrt(2/pi), Eq(Mod(n, 2), 1)))
487
+
488
+
489
+ ###############################################################################
490
+ ######################## RISING and FALLING FACTORIALS ########################
491
+ ###############################################################################
492
+
493
+
494
+ class RisingFactorial(CombinatorialFunction):
495
+ r"""
496
+ Rising factorial (also called Pochhammer symbol [1]_) is a double valued
497
+ function arising in concrete mathematics, hypergeometric functions
498
+ and series expansions. It is defined by:
499
+
500
+ .. math:: \texttt{rf(y, k)} = (x)^k = x \cdot (x+1) \cdots (x+k-1)
501
+
502
+ where `x` can be arbitrary expression and `k` is an integer. For
503
+ more information check "Concrete mathematics" by Graham, pp. 66
504
+ or visit https://mathworld.wolfram.com/RisingFactorial.html page.
505
+
506
+ When `x` is a `~.Poly` instance of degree $\ge 1$ with a single variable,
507
+ `(x)^k = x(y) \cdot x(y+1) \cdots x(y+k-1)`, where `y` is the
508
+ variable of `x`. This is as described in [2]_.
509
+
510
+ Examples
511
+ ========
512
+
513
+ >>> from sympy import rf, Poly
514
+ >>> from sympy.abc import x
515
+ >>> rf(x, 0)
516
+ 1
517
+ >>> rf(1, 5)
518
+ 120
519
+ >>> rf(x, 5) == x*(1 + x)*(2 + x)*(3 + x)*(4 + x)
520
+ True
521
+ >>> rf(Poly(x**3, x), 2)
522
+ Poly(x**6 + 3*x**5 + 3*x**4 + x**3, x, domain='ZZ')
523
+
524
+ Rewriting is complicated unless the relationship between
525
+ the arguments is known, but rising factorial can
526
+ be rewritten in terms of gamma, factorial, binomial,
527
+ and falling factorial.
528
+
529
+ >>> from sympy import Symbol, factorial, ff, binomial, gamma
530
+ >>> n = Symbol('n', integer=True, positive=True)
531
+ >>> R = rf(n, n + 2)
532
+ >>> for i in (rf, ff, factorial, binomial, gamma):
533
+ ... R.rewrite(i)
534
+ ...
535
+ RisingFactorial(n, n + 2)
536
+ FallingFactorial(2*n + 1, n + 2)
537
+ factorial(2*n + 1)/factorial(n - 1)
538
+ binomial(2*n + 1, n + 2)*factorial(n + 2)
539
+ gamma(2*n + 2)/gamma(n)
540
+
541
+ See Also
542
+ ========
543
+
544
+ factorial, factorial2, FallingFactorial
545
+
546
+ References
547
+ ==========
548
+
549
+ .. [1] https://en.wikipedia.org/wiki/Pochhammer_symbol
550
+ .. [2] Peter Paule, "Greatest Factorial Factorization and Symbolic
551
+ Summation", Journal of Symbolic Computation, vol. 20, pp. 235-268,
552
+ 1995.
553
+
554
+ """
555
+
556
+ @classmethod
557
+ def eval(cls, x, k):
558
+ x = sympify(x)
559
+ k = sympify(k)
560
+
561
+ if x is S.NaN or k is S.NaN:
562
+ return S.NaN
563
+ elif x is S.One:
564
+ return factorial(k)
565
+ elif k.is_Integer:
566
+ if k.is_zero:
567
+ return S.One
568
+ else:
569
+ if k.is_positive:
570
+ if x is S.Infinity:
571
+ return S.Infinity
572
+ elif x is S.NegativeInfinity:
573
+ if k.is_odd:
574
+ return S.NegativeInfinity
575
+ else:
576
+ return S.Infinity
577
+ else:
578
+ if isinstance(x, Poly):
579
+ gens = x.gens
580
+ if len(gens)!= 1:
581
+ raise ValueError("rf only defined for "
582
+ "polynomials on one generator")
583
+ else:
584
+ return reduce(lambda r, i:
585
+ r*(x.shift(i)),
586
+ range(int(k)), 1)
587
+ else:
588
+ return reduce(lambda r, i: r*(x + i),
589
+ range(int(k)), 1)
590
+
591
+ else:
592
+ if x is S.Infinity:
593
+ return S.Infinity
594
+ elif x is S.NegativeInfinity:
595
+ return S.Infinity
596
+ else:
597
+ if isinstance(x, Poly):
598
+ gens = x.gens
599
+ if len(gens)!= 1:
600
+ raise ValueError("rf only defined for "
601
+ "polynomials on one generator")
602
+ else:
603
+ return 1/reduce(lambda r, i:
604
+ r*(x.shift(-i)),
605
+ range(1, abs(int(k)) + 1), 1)
606
+ else:
607
+ return 1/reduce(lambda r, i:
608
+ r*(x - i),
609
+ range(1, abs(int(k)) + 1), 1)
610
+
611
+ if k.is_integer == False:
612
+ if x.is_integer and x.is_negative:
613
+ return S.Zero
614
+
615
+ def _eval_rewrite_as_gamma(self, x, k, piecewise=True, **kwargs):
616
+ from sympy.functions.elementary.piecewise import Piecewise
617
+ from sympy.functions.special.gamma_functions import gamma
618
+ if not piecewise:
619
+ if (x <= 0) == True:
620
+ return S.NegativeOne**k*gamma(1 - x) / gamma(-k - x + 1)
621
+ return gamma(x + k) / gamma(x)
622
+ return Piecewise(
623
+ (gamma(x + k) / gamma(x), x > 0),
624
+ (S.NegativeOne**k*gamma(1 - x) / gamma(-k - x + 1), True))
625
+
626
+ def _eval_rewrite_as_FallingFactorial(self, x, k, **kwargs):
627
+ return FallingFactorial(x + k - 1, k)
628
+
629
+ def _eval_rewrite_as_factorial(self, x, k, **kwargs):
630
+ from sympy.functions.elementary.piecewise import Piecewise
631
+ if x.is_integer and k.is_integer:
632
+ return Piecewise(
633
+ (factorial(k + x - 1)/factorial(x - 1), x > 0),
634
+ (S.NegativeOne**k*factorial(-x)/factorial(-k - x), True))
635
+
636
+ def _eval_rewrite_as_binomial(self, x, k, **kwargs):
637
+ if k.is_integer:
638
+ return factorial(k) * binomial(x + k - 1, k)
639
+
640
+ def _eval_rewrite_as_tractable(self, x, k, limitvar=None, **kwargs):
641
+ from sympy.functions.special.gamma_functions import gamma
642
+ if limitvar:
643
+ k_lim = k.subs(limitvar, S.Infinity)
644
+ if k_lim is S.Infinity:
645
+ return (gamma(x + k).rewrite('tractable', deep=True) / gamma(x))
646
+ elif k_lim is S.NegativeInfinity:
647
+ return (S.NegativeOne**k*gamma(1 - x) / gamma(-k - x + 1).rewrite('tractable', deep=True))
648
+ return self.rewrite(gamma).rewrite('tractable', deep=True)
649
+
650
+ def _eval_is_integer(self):
651
+ return fuzzy_and((self.args[0].is_integer, self.args[1].is_integer,
652
+ self.args[1].is_nonnegative))
653
+
654
+
655
+ class FallingFactorial(CombinatorialFunction):
656
+ r"""
657
+ Falling factorial (related to rising factorial) is a double valued
658
+ function arising in concrete mathematics, hypergeometric functions
659
+ and series expansions. It is defined by
660
+
661
+ .. math:: \texttt{ff(x, k)} = (x)_k = x \cdot (x-1) \cdots (x-k+1)
662
+
663
+ where `x` can be arbitrary expression and `k` is an integer. For
664
+ more information check "Concrete mathematics" by Graham, pp. 66
665
+ or [1]_.
666
+
667
+ When `x` is a `~.Poly` instance of degree $\ge 1$ with single variable,
668
+ `(x)_k = x(y) \cdot x(y-1) \cdots x(y-k+1)`, where `y` is the
669
+ variable of `x`. This is as described in
670
+
671
+ >>> from sympy import ff, Poly, Symbol
672
+ >>> from sympy.abc import x
673
+ >>> n = Symbol('n', integer=True)
674
+
675
+ >>> ff(x, 0)
676
+ 1
677
+ >>> ff(5, 5)
678
+ 120
679
+ >>> ff(x, 5) == x*(x - 1)*(x - 2)*(x - 3)*(x - 4)
680
+ True
681
+ >>> ff(Poly(x**2, x), 2)
682
+ Poly(x**4 - 2*x**3 + x**2, x, domain='ZZ')
683
+ >>> ff(n, n)
684
+ factorial(n)
685
+
686
+ Rewriting is complicated unless the relationship between
687
+ the arguments is known, but falling factorial can
688
+ be rewritten in terms of gamma, factorial and binomial
689
+ and rising factorial.
690
+
691
+ >>> from sympy import factorial, rf, gamma, binomial, Symbol
692
+ >>> n = Symbol('n', integer=True, positive=True)
693
+ >>> F = ff(n, n - 2)
694
+ >>> for i in (rf, ff, factorial, binomial, gamma):
695
+ ... F.rewrite(i)
696
+ ...
697
+ RisingFactorial(3, n - 2)
698
+ FallingFactorial(n, n - 2)
699
+ factorial(n)/2
700
+ binomial(n, n - 2)*factorial(n - 2)
701
+ gamma(n + 1)/2
702
+
703
+ See Also
704
+ ========
705
+
706
+ factorial, factorial2, RisingFactorial
707
+
708
+ References
709
+ ==========
710
+
711
+ .. [1] https://mathworld.wolfram.com/FallingFactorial.html
712
+ .. [2] Peter Paule, "Greatest Factorial Factorization and Symbolic
713
+ Summation", Journal of Symbolic Computation, vol. 20, pp. 235-268,
714
+ 1995.
715
+
716
+ """
717
+
718
+ @classmethod
719
+ def eval(cls, x, k):
720
+ x = sympify(x)
721
+ k = sympify(k)
722
+
723
+ if x is S.NaN or k is S.NaN:
724
+ return S.NaN
725
+ elif k.is_integer and x == k:
726
+ return factorial(x)
727
+ elif k.is_Integer:
728
+ if k.is_zero:
729
+ return S.One
730
+ else:
731
+ if k.is_positive:
732
+ if x is S.Infinity:
733
+ return S.Infinity
734
+ elif x is S.NegativeInfinity:
735
+ if k.is_odd:
736
+ return S.NegativeInfinity
737
+ else:
738
+ return S.Infinity
739
+ else:
740
+ if isinstance(x, Poly):
741
+ gens = x.gens
742
+ if len(gens)!= 1:
743
+ raise ValueError("ff only defined for "
744
+ "polynomials on one generator")
745
+ else:
746
+ return reduce(lambda r, i:
747
+ r*(x.shift(-i)),
748
+ range(int(k)), 1)
749
+ else:
750
+ return reduce(lambda r, i: r*(x - i),
751
+ range(int(k)), 1)
752
+ else:
753
+ if x is S.Infinity:
754
+ return S.Infinity
755
+ elif x is S.NegativeInfinity:
756
+ return S.Infinity
757
+ else:
758
+ if isinstance(x, Poly):
759
+ gens = x.gens
760
+ if len(gens)!= 1:
761
+ raise ValueError("rf only defined for "
762
+ "polynomials on one generator")
763
+ else:
764
+ return 1/reduce(lambda r, i:
765
+ r*(x.shift(i)),
766
+ range(1, abs(int(k)) + 1), 1)
767
+ else:
768
+ return 1/reduce(lambda r, i: r*(x + i),
769
+ range(1, abs(int(k)) + 1), 1)
770
+
771
+ def _eval_rewrite_as_gamma(self, x, k, piecewise=True, **kwargs):
772
+ from sympy.functions.elementary.piecewise import Piecewise
773
+ from sympy.functions.special.gamma_functions import gamma
774
+ if not piecewise:
775
+ if (x < 0) == True:
776
+ return S.NegativeOne**k*gamma(k - x) / gamma(-x)
777
+ return gamma(x + 1) / gamma(x - k + 1)
778
+ return Piecewise(
779
+ (gamma(x + 1) / gamma(x - k + 1), x >= 0),
780
+ (S.NegativeOne**k*gamma(k - x) / gamma(-x), True))
781
+
782
+ def _eval_rewrite_as_RisingFactorial(self, x, k, **kwargs):
783
+ return rf(x - k + 1, k)
784
+
785
+ def _eval_rewrite_as_binomial(self, x, k, **kwargs):
786
+ if k.is_integer:
787
+ return factorial(k) * binomial(x, k)
788
+
789
+ def _eval_rewrite_as_factorial(self, x, k, **kwargs):
790
+ from sympy.functions.elementary.piecewise import Piecewise
791
+ if x.is_integer and k.is_integer:
792
+ return Piecewise(
793
+ (factorial(x)/factorial(-k + x), x >= 0),
794
+ (S.NegativeOne**k*factorial(k - x - 1)/factorial(-x - 1), True))
795
+
796
+ def _eval_rewrite_as_tractable(self, x, k, limitvar=None, **kwargs):
797
+ from sympy.functions.special.gamma_functions import gamma
798
+ if limitvar:
799
+ k_lim = k.subs(limitvar, S.Infinity)
800
+ if k_lim is S.Infinity:
801
+ return (S.NegativeOne**k*gamma(k - x).rewrite('tractable', deep=True) / gamma(-x))
802
+ elif k_lim is S.NegativeInfinity:
803
+ return (gamma(x + 1) / gamma(x - k + 1).rewrite('tractable', deep=True))
804
+ return self.rewrite(gamma).rewrite('tractable', deep=True)
805
+
806
+ def _eval_is_integer(self):
807
+ return fuzzy_and((self.args[0].is_integer, self.args[1].is_integer,
808
+ self.args[1].is_nonnegative))
809
+
810
+
811
+ rf = RisingFactorial
812
+ ff = FallingFactorial
813
+
814
+ ###############################################################################
815
+ ########################### BINOMIAL COEFFICIENTS #############################
816
+ ###############################################################################
817
+
818
+
819
+ class binomial(CombinatorialFunction):
820
+ r"""Implementation of the binomial coefficient. It can be defined
821
+ in two ways depending on its desired interpretation:
822
+
823
+ .. math:: \binom{n}{k} = \frac{n!}{k!(n-k)!}\ \text{or}\
824
+ \binom{n}{k} = \frac{(n)_k}{k!}
825
+
826
+ First, in a strict combinatorial sense it defines the
827
+ number of ways we can choose `k` elements from a set of
828
+ `n` elements. In this case both arguments are nonnegative
829
+ integers and binomial is computed using an efficient
830
+ algorithm based on prime factorization.
831
+
832
+ The other definition is generalization for arbitrary `n`,
833
+ however `k` must also be nonnegative. This case is very
834
+ useful when evaluating summations.
835
+
836
+ For the sake of convenience, for negative integer `k` this function
837
+ will return zero no matter the other argument.
838
+
839
+ To expand the binomial when `n` is a symbol, use either
840
+ ``expand_func()`` or ``expand(func=True)``. The former will keep
841
+ the polynomial in factored form while the latter will expand the
842
+ polynomial itself. See examples for details.
843
+
844
+ Examples
845
+ ========
846
+
847
+ >>> from sympy import Symbol, Rational, binomial, expand_func
848
+ >>> n = Symbol('n', integer=True, positive=True)
849
+
850
+ >>> binomial(15, 8)
851
+ 6435
852
+
853
+ >>> binomial(n, -1)
854
+ 0
855
+
856
+ Rows of Pascal's triangle can be generated with the binomial function:
857
+
858
+ >>> for N in range(8):
859
+ ... print([binomial(N, i) for i in range(N + 1)])
860
+ ...
861
+ [1]
862
+ [1, 1]
863
+ [1, 2, 1]
864
+ [1, 3, 3, 1]
865
+ [1, 4, 6, 4, 1]
866
+ [1, 5, 10, 10, 5, 1]
867
+ [1, 6, 15, 20, 15, 6, 1]
868
+ [1, 7, 21, 35, 35, 21, 7, 1]
869
+
870
+ As can a given diagonal, e.g. the 4th diagonal:
871
+
872
+ >>> N = -4
873
+ >>> [binomial(N, i) for i in range(1 - N)]
874
+ [1, -4, 10, -20, 35]
875
+
876
+ >>> binomial(Rational(5, 4), 3)
877
+ -5/128
878
+ >>> binomial(Rational(-5, 4), 3)
879
+ -195/128
880
+
881
+ >>> binomial(n, 3)
882
+ binomial(n, 3)
883
+
884
+ >>> binomial(n, 3).expand(func=True)
885
+ n**3/6 - n**2/2 + n/3
886
+
887
+ >>> expand_func(binomial(n, 3))
888
+ n*(n - 2)*(n - 1)/6
889
+
890
+ References
891
+ ==========
892
+
893
+ .. [1] https://www.johndcook.com/blog/binomial_coefficients/
894
+
895
+ """
896
+
897
+ def fdiff(self, argindex=1):
898
+ from sympy.functions.special.gamma_functions import polygamma
899
+ if argindex == 1:
900
+ # https://functions.wolfram.com/GammaBetaErf/Binomial/20/01/01/
901
+ n, k = self.args
902
+ return binomial(n, k)*(polygamma(0, n + 1) - \
903
+ polygamma(0, n - k + 1))
904
+ elif argindex == 2:
905
+ # https://functions.wolfram.com/GammaBetaErf/Binomial/20/01/02/
906
+ n, k = self.args
907
+ return binomial(n, k)*(polygamma(0, n - k + 1) - \
908
+ polygamma(0, k + 1))
909
+ else:
910
+ raise ArgumentIndexError(self, argindex)
911
+
912
+ @classmethod
913
+ def _eval(self, n, k):
914
+ # n.is_Number and k.is_Integer and k != 1 and n != k
915
+
916
+ if k.is_Integer:
917
+ if n.is_Integer and n >= 0:
918
+ n, k = int(n), int(k)
919
+
920
+ if k > n:
921
+ return S.Zero
922
+ elif k > n // 2:
923
+ k = n - k
924
+
925
+ if HAS_GMPY:
926
+ return Integer(gmpy.bincoef(n, k))
927
+
928
+ d, result = n - k, 1
929
+ for i in range(1, k + 1):
930
+ d += 1
931
+ result = result * d // i
932
+ return Integer(result)
933
+ else:
934
+ d, result = n - k, 1
935
+ for i in range(1, k + 1):
936
+ d += 1
937
+ result *= d
938
+ return result / _factorial(k)
939
+
940
+ @classmethod
941
+ def eval(cls, n, k):
942
+ n, k = map(sympify, (n, k))
943
+ d = n - k
944
+ n_nonneg, n_isint = n.is_nonnegative, n.is_integer
945
+ if k.is_zero or ((n_nonneg or n_isint is False)
946
+ and d.is_zero):
947
+ return S.One
948
+ if (k - 1).is_zero or ((n_nonneg or n_isint is False)
949
+ and (d - 1).is_zero):
950
+ return n
951
+ if k.is_integer:
952
+ if k.is_negative or (n_nonneg and n_isint and d.is_negative):
953
+ return S.Zero
954
+ elif n.is_number:
955
+ res = cls._eval(n, k)
956
+ return res.expand(basic=True) if res else res
957
+ elif n_nonneg is False and n_isint:
958
+ # a special case when binomial evaluates to complex infinity
959
+ return S.ComplexInfinity
960
+ elif k.is_number:
961
+ from sympy.functions.special.gamma_functions import gamma
962
+ return gamma(n + 1)/(gamma(k + 1)*gamma(n - k + 1))
963
+
964
+ def _eval_Mod(self, q):
965
+ n, k = self.args
966
+
967
+ if any(x.is_integer is False for x in (n, k, q)):
968
+ raise ValueError("Integers expected for binomial Mod")
969
+
970
+ if all(x.is_Integer for x in (n, k, q)):
971
+ n, k = map(int, (n, k))
972
+ aq, res = abs(q), 1
973
+
974
+ # handle negative integers k or n
975
+ if k < 0:
976
+ return S.Zero
977
+ if n < 0:
978
+ n = -n + k - 1
979
+ res = -1 if k%2 else 1
980
+
981
+ # non negative integers k and n
982
+ if k > n:
983
+ return S.Zero
984
+
985
+ isprime = aq.is_prime
986
+ aq = int(aq)
987
+ if isprime:
988
+ if aq < n:
989
+ # use Lucas Theorem
990
+ N, K = n, k
991
+ while N or K:
992
+ res = res*binomial(N % aq, K % aq) % aq
993
+ N, K = N // aq, K // aq
994
+
995
+ else:
996
+ # use Factorial Modulo
997
+ d = n - k
998
+ if k > d:
999
+ k, d = d, k
1000
+ kf = 1
1001
+ for i in range(2, k + 1):
1002
+ kf = kf*i % aq
1003
+ df = kf
1004
+ for i in range(k + 1, d + 1):
1005
+ df = df*i % aq
1006
+ res *= df
1007
+ for i in range(d + 1, n + 1):
1008
+ res = res*i % aq
1009
+
1010
+ res *= pow(kf*df % aq, aq - 2, aq)
1011
+ res %= aq
1012
+
1013
+ else:
1014
+ # Binomial Factorization is performed by calculating the
1015
+ # exponents of primes <= n in `n! /(k! (n - k)!)`,
1016
+ # for non-negative integers n and k. As the exponent of
1017
+ # prime in n! is e_p(n) = [n/p] + [n/p**2] + ...
1018
+ # the exponent of prime in binomial(n, k) would be
1019
+ # e_p(n) - e_p(k) - e_p(n - k)
1020
+ M = int(_sqrt(n))
1021
+ for prime in sieve.primerange(2, n + 1):
1022
+ if prime > n - k:
1023
+ res = res*prime % aq
1024
+ elif prime > n // 2:
1025
+ continue
1026
+ elif prime > M:
1027
+ if n % prime < k % prime:
1028
+ res = res*prime % aq
1029
+ else:
1030
+ N, K = n, k
1031
+ exp = a = 0
1032
+
1033
+ while N > 0:
1034
+ a = int((N % prime) < (K % prime + a))
1035
+ N, K = N // prime, K // prime
1036
+ exp += a
1037
+
1038
+ if exp > 0:
1039
+ res *= pow(prime, exp, aq)
1040
+ res %= aq
1041
+
1042
+ return S(res % q)
1043
+
1044
+ def _eval_expand_func(self, **hints):
1045
+ """
1046
+ Function to expand binomial(n, k) when m is positive integer
1047
+ Also,
1048
+ n is self.args[0] and k is self.args[1] while using binomial(n, k)
1049
+ """
1050
+ n = self.args[0]
1051
+ if n.is_Number:
1052
+ return binomial(*self.args)
1053
+
1054
+ k = self.args[1]
1055
+ if (n-k).is_Integer:
1056
+ k = n - k
1057
+
1058
+ if k.is_Integer:
1059
+ if k.is_zero:
1060
+ return S.One
1061
+ elif k.is_negative:
1062
+ return S.Zero
1063
+ else:
1064
+ n, result = self.args[0], 1
1065
+ for i in range(1, k + 1):
1066
+ result *= n - k + i
1067
+ return result / _factorial(k)
1068
+ else:
1069
+ return binomial(*self.args)
1070
+
1071
+ def _eval_rewrite_as_factorial(self, n, k, **kwargs):
1072
+ return factorial(n)/(factorial(k)*factorial(n - k))
1073
+
1074
+ def _eval_rewrite_as_gamma(self, n, k, piecewise=True, **kwargs):
1075
+ from sympy.functions.special.gamma_functions import gamma
1076
+ return gamma(n + 1)/(gamma(k + 1)*gamma(n - k + 1))
1077
+
1078
+ def _eval_rewrite_as_tractable(self, n, k, limitvar=None, **kwargs):
1079
+ return self._eval_rewrite_as_gamma(n, k).rewrite('tractable')
1080
+
1081
+ def _eval_rewrite_as_FallingFactorial(self, n, k, **kwargs):
1082
+ if k.is_integer:
1083
+ return ff(n, k) / factorial(k)
1084
+
1085
+ def _eval_is_integer(self):
1086
+ n, k = self.args
1087
+ if n.is_integer and k.is_integer:
1088
+ return True
1089
+ elif k.is_integer is False:
1090
+ return False
1091
+
1092
+ def _eval_is_nonnegative(self):
1093
+ n, k = self.args
1094
+ if n.is_integer and k.is_integer:
1095
+ if n.is_nonnegative or k.is_negative or k.is_even:
1096
+ return True
1097
+ elif k.is_even is False:
1098
+ return False
1099
+
1100
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
1101
+ from sympy.functions.special.gamma_functions import gamma
1102
+ return self.rewrite(gamma)._eval_as_leading_term(x, logx=logx, cdir=cdir)
venv/lib/python3.10/site-packages/sympy/functions/combinatorial/numbers.py ADDED
@@ -0,0 +1,2563 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ """
2
+ This module implements some special functions that commonly appear in
3
+ combinatorial contexts (e.g. in power series); in particular,
4
+ sequences of rational numbers such as Bernoulli and Fibonacci numbers.
5
+
6
+ Factorials, binomial coefficients and related functions are located in
7
+ the separate 'factorials' module.
8
+ """
9
+ from math import prod
10
+ from collections import defaultdict
11
+ from typing import Tuple as tTuple
12
+
13
+ from sympy.core import S, Symbol, Add, Dummy
14
+ from sympy.core.cache import cacheit
15
+ from sympy.core.expr import Expr
16
+ from sympy.core.function import ArgumentIndexError, Function, expand_mul
17
+ from sympy.core.logic import fuzzy_not
18
+ from sympy.core.mul import Mul
19
+ from sympy.core.numbers import E, I, pi, oo, Rational, Integer
20
+ from sympy.core.relational import Eq, is_le, is_gt
21
+ from sympy.external.gmpy import SYMPY_INTS
22
+ from sympy.functions.combinatorial.factorials import (binomial,
23
+ factorial, subfactorial)
24
+ from sympy.functions.elementary.exponential import log
25
+ from sympy.functions.elementary.piecewise import Piecewise
26
+ from sympy.ntheory.primetest import isprime, is_square
27
+ from sympy.polys.appellseqs import bernoulli_poly, euler_poly, genocchi_poly
28
+ from sympy.utilities.enumerative import MultisetPartitionTraverser
29
+ from sympy.utilities.exceptions import sympy_deprecation_warning
30
+ from sympy.utilities.iterables import multiset, multiset_derangements, iterable
31
+ from sympy.utilities.memoization import recurrence_memo
32
+ from sympy.utilities.misc import as_int
33
+
34
+ from mpmath import mp, workprec
35
+ from mpmath.libmp import ifib as _ifib
36
+
37
+
38
+ def _product(a, b):
39
+ return prod(range(a, b + 1))
40
+
41
+
42
+ # Dummy symbol used for computing polynomial sequences
43
+ _sym = Symbol('x')
44
+
45
+
46
+ #----------------------------------------------------------------------------#
47
+ # #
48
+ # Carmichael numbers #
49
+ # #
50
+ #----------------------------------------------------------------------------#
51
+
52
+ def _divides(p, n):
53
+ return n % p == 0
54
+
55
+ class carmichael(Function):
56
+ r"""
57
+ Carmichael Numbers:
58
+
59
+ Certain cryptographic algorithms make use of big prime numbers.
60
+ However, checking whether a big number is prime is not so easy.
61
+ Randomized prime number checking tests exist that offer a high degree of
62
+ confidence of accurate determination at low cost, such as the Fermat test.
63
+
64
+ Let 'a' be a random number between $2$ and $n - 1$, where $n$ is the
65
+ number whose primality we are testing. Then, $n$ is probably prime if it
66
+ satisfies the modular arithmetic congruence relation:
67
+
68
+ .. math :: a^{n-1} = 1 \pmod{n}
69
+
70
+ (where mod refers to the modulo operation)
71
+
72
+ If a number passes the Fermat test several times, then it is prime with a
73
+ high probability.
74
+
75
+ Unfortunately, certain composite numbers (non-primes) still pass the Fermat
76
+ test with every number smaller than themselves.
77
+ These numbers are called Carmichael numbers.
78
+
79
+ A Carmichael number will pass a Fermat primality test to every base $b$
80
+ relatively prime to the number, even though it is not actually prime.
81
+ This makes tests based on Fermat's Little Theorem less effective than
82
+ strong probable prime tests such as the Baillie-PSW primality test and
83
+ the Miller-Rabin primality test.
84
+
85
+ Examples
86
+ ========
87
+
88
+ >>> from sympy import carmichael
89
+ >>> carmichael.find_first_n_carmichaels(5)
90
+ [561, 1105, 1729, 2465, 2821]
91
+ >>> carmichael.find_carmichael_numbers_in_range(0, 562)
92
+ [561]
93
+ >>> carmichael.find_carmichael_numbers_in_range(0,1000)
94
+ [561]
95
+ >>> carmichael.find_carmichael_numbers_in_range(0,2000)
96
+ [561, 1105, 1729]
97
+
98
+ References
99
+ ==========
100
+
101
+ .. [1] https://en.wikipedia.org/wiki/Carmichael_number
102
+ .. [2] https://en.wikipedia.org/wiki/Fermat_primality_test
103
+ .. [3] https://www.jstor.org/stable/23248683?seq=1#metadata_info_tab_contents
104
+ """
105
+
106
+ @staticmethod
107
+ def is_perfect_square(n):
108
+ sympy_deprecation_warning(
109
+ """
110
+ is_perfect_square is just a wrapper around sympy.ntheory.primetest.is_square
111
+ so use that directly instead.
112
+ """,
113
+ deprecated_since_version="1.11",
114
+ active_deprecations_target='deprecated-carmichael-static-methods',
115
+ )
116
+ return is_square(n)
117
+
118
+ @staticmethod
119
+ def divides(p, n):
120
+ sympy_deprecation_warning(
121
+ """
122
+ divides can be replaced by directly testing n % p == 0.
123
+ """,
124
+ deprecated_since_version="1.11",
125
+ active_deprecations_target='deprecated-carmichael-static-methods',
126
+ )
127
+ return n % p == 0
128
+
129
+ @staticmethod
130
+ def is_prime(n):
131
+ sympy_deprecation_warning(
132
+ """
133
+ is_prime is just a wrapper around sympy.ntheory.primetest.isprime so use that
134
+ directly instead.
135
+ """,
136
+ deprecated_since_version="1.11",
137
+ active_deprecations_target='deprecated-carmichael-static-methods',
138
+ )
139
+ return isprime(n)
140
+
141
+ @staticmethod
142
+ def is_carmichael(n):
143
+ if n >= 0:
144
+ if (n == 1) or isprime(n) or (n % 2 == 0):
145
+ return False
146
+
147
+ divisors = [1, n]
148
+
149
+ # get divisors
150
+ divisors.extend([i for i in range(3, n // 2 + 1, 2) if n % i == 0])
151
+
152
+ for i in divisors:
153
+ if is_square(i) and i != 1:
154
+ return False
155
+ if isprime(i):
156
+ if not _divides(i - 1, n - 1):
157
+ return False
158
+
159
+ return True
160
+
161
+ else:
162
+ raise ValueError('The provided number must be greater than or equal to 0')
163
+
164
+ @staticmethod
165
+ def find_carmichael_numbers_in_range(x, y):
166
+ if 0 <= x <= y:
167
+ if x % 2 == 0:
168
+ return [i for i in range(x + 1, y, 2) if carmichael.is_carmichael(i)]
169
+ else:
170
+ return [i for i in range(x, y, 2) if carmichael.is_carmichael(i)]
171
+
172
+ else:
173
+ raise ValueError('The provided range is not valid. x and y must be non-negative integers and x <= y')
174
+
175
+ @staticmethod
176
+ def find_first_n_carmichaels(n):
177
+ i = 1
178
+ carmichaels = []
179
+
180
+ while len(carmichaels) < n:
181
+ if carmichael.is_carmichael(i):
182
+ carmichaels.append(i)
183
+ i += 2
184
+
185
+ return carmichaels
186
+
187
+
188
+ #----------------------------------------------------------------------------#
189
+ # #
190
+ # Fibonacci numbers #
191
+ # #
192
+ #----------------------------------------------------------------------------#
193
+
194
+
195
+ class fibonacci(Function):
196
+ r"""
197
+ Fibonacci numbers / Fibonacci polynomials
198
+
199
+ The Fibonacci numbers are the integer sequence defined by the
200
+ initial terms `F_0 = 0`, `F_1 = 1` and the two-term recurrence
201
+ relation `F_n = F_{n-1} + F_{n-2}`. This definition
202
+ extended to arbitrary real and complex arguments using
203
+ the formula
204
+
205
+ .. math :: F_z = \frac{\phi^z - \cos(\pi z) \phi^{-z}}{\sqrt 5}
206
+
207
+ The Fibonacci polynomials are defined by `F_1(x) = 1`,
208
+ `F_2(x) = x`, and `F_n(x) = x*F_{n-1}(x) + F_{n-2}(x)` for `n > 2`.
209
+ For all positive integers `n`, `F_n(1) = F_n`.
210
+
211
+ * ``fibonacci(n)`` gives the `n^{th}` Fibonacci number, `F_n`
212
+ * ``fibonacci(n, x)`` gives the `n^{th}` Fibonacci polynomial in `x`, `F_n(x)`
213
+
214
+ Examples
215
+ ========
216
+
217
+ >>> from sympy import fibonacci, Symbol
218
+
219
+ >>> [fibonacci(x) for x in range(11)]
220
+ [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55]
221
+ >>> fibonacci(5, Symbol('t'))
222
+ t**4 + 3*t**2 + 1
223
+
224
+ See Also
225
+ ========
226
+
227
+ bell, bernoulli, catalan, euler, harmonic, lucas, genocchi, partition, tribonacci
228
+
229
+ References
230
+ ==========
231
+
232
+ .. [1] https://en.wikipedia.org/wiki/Fibonacci_number
233
+ .. [2] https://mathworld.wolfram.com/FibonacciNumber.html
234
+
235
+ """
236
+
237
+ @staticmethod
238
+ def _fib(n):
239
+ return _ifib(n)
240
+
241
+ @staticmethod
242
+ @recurrence_memo([None, S.One, _sym])
243
+ def _fibpoly(n, prev):
244
+ return (prev[-2] + _sym*prev[-1]).expand()
245
+
246
+ @classmethod
247
+ def eval(cls, n, sym=None):
248
+ if n is S.Infinity:
249
+ return S.Infinity
250
+
251
+ if n.is_Integer:
252
+ if sym is None:
253
+ n = int(n)
254
+ if n < 0:
255
+ return S.NegativeOne**(n + 1) * fibonacci(-n)
256
+ else:
257
+ return Integer(cls._fib(n))
258
+ else:
259
+ if n < 1:
260
+ raise ValueError("Fibonacci polynomials are defined "
261
+ "only for positive integer indices.")
262
+ return cls._fibpoly(n).subs(_sym, sym)
263
+
264
+ def _eval_rewrite_as_sqrt(self, n, **kwargs):
265
+ from sympy.functions.elementary.miscellaneous import sqrt
266
+ return 2**(-n)*sqrt(5)*((1 + sqrt(5))**n - (-sqrt(5) + 1)**n) / 5
267
+
268
+ def _eval_rewrite_as_GoldenRatio(self,n, **kwargs):
269
+ return (S.GoldenRatio**n - 1/(-S.GoldenRatio)**n)/(2*S.GoldenRatio-1)
270
+
271
+
272
+ #----------------------------------------------------------------------------#
273
+ # #
274
+ # Lucas numbers #
275
+ # #
276
+ #----------------------------------------------------------------------------#
277
+
278
+
279
+ class lucas(Function):
280
+ """
281
+ Lucas numbers
282
+
283
+ Lucas numbers satisfy a recurrence relation similar to that of
284
+ the Fibonacci sequence, in which each term is the sum of the
285
+ preceding two. They are generated by choosing the initial
286
+ values `L_0 = 2` and `L_1 = 1`.
287
+
288
+ * ``lucas(n)`` gives the `n^{th}` Lucas number
289
+
290
+ Examples
291
+ ========
292
+
293
+ >>> from sympy import lucas
294
+
295
+ >>> [lucas(x) for x in range(11)]
296
+ [2, 1, 3, 4, 7, 11, 18, 29, 47, 76, 123]
297
+
298
+ See Also
299
+ ========
300
+
301
+ bell, bernoulli, catalan, euler, fibonacci, harmonic, genocchi, partition, tribonacci
302
+
303
+ References
304
+ ==========
305
+
306
+ .. [1] https://en.wikipedia.org/wiki/Lucas_number
307
+ .. [2] https://mathworld.wolfram.com/LucasNumber.html
308
+
309
+ """
310
+
311
+ @classmethod
312
+ def eval(cls, n):
313
+ if n is S.Infinity:
314
+ return S.Infinity
315
+
316
+ if n.is_Integer:
317
+ return fibonacci(n + 1) + fibonacci(n - 1)
318
+
319
+ def _eval_rewrite_as_sqrt(self, n, **kwargs):
320
+ from sympy.functions.elementary.miscellaneous import sqrt
321
+ return 2**(-n)*((1 + sqrt(5))**n + (-sqrt(5) + 1)**n)
322
+
323
+
324
+ #----------------------------------------------------------------------------#
325
+ # #
326
+ # Tribonacci numbers #
327
+ # #
328
+ #----------------------------------------------------------------------------#
329
+
330
+
331
+ class tribonacci(Function):
332
+ r"""
333
+ Tribonacci numbers / Tribonacci polynomials
334
+
335
+ The Tribonacci numbers are the integer sequence defined by the
336
+ initial terms `T_0 = 0`, `T_1 = 1`, `T_2 = 1` and the three-term
337
+ recurrence relation `T_n = T_{n-1} + T_{n-2} + T_{n-3}`.
338
+
339
+ The Tribonacci polynomials are defined by `T_0(x) = 0`, `T_1(x) = 1`,
340
+ `T_2(x) = x^2`, and `T_n(x) = x^2 T_{n-1}(x) + x T_{n-2}(x) + T_{n-3}(x)`
341
+ for `n > 2`. For all positive integers `n`, `T_n(1) = T_n`.
342
+
343
+ * ``tribonacci(n)`` gives the `n^{th}` Tribonacci number, `T_n`
344
+ * ``tribonacci(n, x)`` gives the `n^{th}` Tribonacci polynomial in `x`, `T_n(x)`
345
+
346
+ Examples
347
+ ========
348
+
349
+ >>> from sympy import tribonacci, Symbol
350
+
351
+ >>> [tribonacci(x) for x in range(11)]
352
+ [0, 1, 1, 2, 4, 7, 13, 24, 44, 81, 149]
353
+ >>> tribonacci(5, Symbol('t'))
354
+ t**8 + 3*t**5 + 3*t**2
355
+
356
+ See Also
357
+ ========
358
+
359
+ bell, bernoulli, catalan, euler, fibonacci, harmonic, lucas, genocchi, partition
360
+
361
+ References
362
+ ==========
363
+
364
+ .. [1] https://en.wikipedia.org/wiki/Generalizations_of_Fibonacci_numbers#Tribonacci_numbers
365
+ .. [2] https://mathworld.wolfram.com/TribonacciNumber.html
366
+ .. [3] https://oeis.org/A000073
367
+
368
+ """
369
+
370
+ @staticmethod
371
+ @recurrence_memo([S.Zero, S.One, S.One])
372
+ def _trib(n, prev):
373
+ return (prev[-3] + prev[-2] + prev[-1])
374
+
375
+ @staticmethod
376
+ @recurrence_memo([S.Zero, S.One, _sym**2])
377
+ def _tribpoly(n, prev):
378
+ return (prev[-3] + _sym*prev[-2] + _sym**2*prev[-1]).expand()
379
+
380
+ @classmethod
381
+ def eval(cls, n, sym=None):
382
+ if n is S.Infinity:
383
+ return S.Infinity
384
+
385
+ if n.is_Integer:
386
+ n = int(n)
387
+ if n < 0:
388
+ raise ValueError("Tribonacci polynomials are defined "
389
+ "only for non-negative integer indices.")
390
+ if sym is None:
391
+ return Integer(cls._trib(n))
392
+ else:
393
+ return cls._tribpoly(n).subs(_sym, sym)
394
+
395
+ def _eval_rewrite_as_sqrt(self, n, **kwargs):
396
+ from sympy.functions.elementary.miscellaneous import cbrt, sqrt
397
+ w = (-1 + S.ImaginaryUnit * sqrt(3)) / 2
398
+ a = (1 + cbrt(19 + 3*sqrt(33)) + cbrt(19 - 3*sqrt(33))) / 3
399
+ b = (1 + w*cbrt(19 + 3*sqrt(33)) + w**2*cbrt(19 - 3*sqrt(33))) / 3
400
+ c = (1 + w**2*cbrt(19 + 3*sqrt(33)) + w*cbrt(19 - 3*sqrt(33))) / 3
401
+ Tn = (a**(n + 1)/((a - b)*(a - c))
402
+ + b**(n + 1)/((b - a)*(b - c))
403
+ + c**(n + 1)/((c - a)*(c - b)))
404
+ return Tn
405
+
406
+ def _eval_rewrite_as_TribonacciConstant(self, n, **kwargs):
407
+ from sympy.functions.elementary.integers import floor
408
+ from sympy.functions.elementary.miscellaneous import cbrt, sqrt
409
+ b = cbrt(586 + 102*sqrt(33))
410
+ Tn = 3 * b * S.TribonacciConstant**n / (b**2 - 2*b + 4)
411
+ return floor(Tn + S.Half)
412
+
413
+
414
+ #----------------------------------------------------------------------------#
415
+ # #
416
+ # Bernoulli numbers #
417
+ # #
418
+ #----------------------------------------------------------------------------#
419
+
420
+
421
+ class bernoulli(Function):
422
+ r"""
423
+ Bernoulli numbers / Bernoulli polynomials / Bernoulli function
424
+
425
+ The Bernoulli numbers are a sequence of rational numbers
426
+ defined by `B_0 = 1` and the recursive relation (`n > 0`):
427
+
428
+ .. math :: n+1 = \sum_{k=0}^n \binom{n+1}{k} B_k
429
+
430
+ They are also commonly defined by their exponential generating
431
+ function, which is `\frac{x}{1 - e^{-x}}`. For odd indices > 1,
432
+ the Bernoulli numbers are zero.
433
+
434
+ The Bernoulli polynomials satisfy the analogous formula:
435
+
436
+ .. math :: B_n(x) = \sum_{k=0}^n (-1)^k \binom{n}{k} B_k x^{n-k}
437
+
438
+ Bernoulli numbers and Bernoulli polynomials are related as
439
+ `B_n(1) = B_n`.
440
+
441
+ The generalized Bernoulli function `\operatorname{B}(s, a)`
442
+ is defined for any complex `s` and `a`, except where `a` is a
443
+ nonpositive integer and `s` is not a nonnegative integer. It is
444
+ an entire function of `s` for fixed `a`, related to the Hurwitz
445
+ zeta function by
446
+
447
+ .. math:: \operatorname{B}(s, a) = \begin{cases}
448
+ -s \zeta(1-s, a) & s \ne 0 \\ 1 & s = 0 \end{cases}
449
+
450
+ When `s` is a nonnegative integer this function reduces to the
451
+ Bernoulli polynomials: `\operatorname{B}(n, x) = B_n(x)`. When
452
+ `a` is omitted it is assumed to be 1, yielding the (ordinary)
453
+ Bernoulli function which interpolates the Bernoulli numbers and is
454
+ related to the Riemann zeta function.
455
+
456
+ We compute Bernoulli numbers using Ramanujan's formula:
457
+
458
+ .. math :: B_n = \frac{A(n) - S(n)}{\binom{n+3}{n}}
459
+
460
+ where:
461
+
462
+ .. math :: A(n) = \begin{cases} \frac{n+3}{3} &
463
+ n \equiv 0\ \text{or}\ 2 \pmod{6} \\
464
+ -\frac{n+3}{6} & n \equiv 4 \pmod{6} \end{cases}
465
+
466
+ and:
467
+
468
+ .. math :: S(n) = \sum_{k=1}^{[n/6]} \binom{n+3}{n-6k} B_{n-6k}
469
+
470
+ This formula is similar to the sum given in the definition, but
471
+ cuts `\frac{2}{3}` of the terms. For Bernoulli polynomials, we use
472
+ Appell sequences.
473
+
474
+ For `n` a nonnegative integer and `s`, `a`, `x` arbitrary complex numbers,
475
+
476
+ * ``bernoulli(n)`` gives the nth Bernoulli number, `B_n`
477
+ * ``bernoulli(s)`` gives the Bernoulli function `\operatorname{B}(s)`
478
+ * ``bernoulli(n, x)`` gives the nth Bernoulli polynomial in `x`, `B_n(x)`
479
+ * ``bernoulli(s, a)`` gives the generalized Bernoulli function
480
+ `\operatorname{B}(s, a)`
481
+
482
+ .. versionchanged:: 1.12
483
+ ``bernoulli(1)`` gives `+\frac{1}{2}` instead of `-\frac{1}{2}`.
484
+ This choice of value confers several theoretical advantages [5]_,
485
+ including the extension to complex parameters described above
486
+ which this function now implements. The previous behavior, defined
487
+ only for nonnegative integers `n`, can be obtained with
488
+ ``(-1)**n*bernoulli(n)``.
489
+
490
+ Examples
491
+ ========
492
+
493
+ >>> from sympy import bernoulli
494
+ >>> from sympy.abc import x
495
+ >>> [bernoulli(n) for n in range(11)]
496
+ [1, 1/2, 1/6, 0, -1/30, 0, 1/42, 0, -1/30, 0, 5/66]
497
+ >>> bernoulli(1000001)
498
+ 0
499
+ >>> bernoulli(3, x)
500
+ x**3 - 3*x**2/2 + x/2
501
+
502
+ See Also
503
+ ========
504
+
505
+ andre, bell, catalan, euler, fibonacci, harmonic, lucas, genocchi,
506
+ partition, tribonacci, sympy.polys.appellseqs.bernoulli_poly
507
+
508
+ References
509
+ ==========
510
+
511
+ .. [1] https://en.wikipedia.org/wiki/Bernoulli_number
512
+ .. [2] https://en.wikipedia.org/wiki/Bernoulli_polynomial
513
+ .. [3] https://mathworld.wolfram.com/BernoulliNumber.html
514
+ .. [4] https://mathworld.wolfram.com/BernoulliPolynomial.html
515
+ .. [5] Peter Luschny, "The Bernoulli Manifesto",
516
+ https://luschny.de/math/zeta/The-Bernoulli-Manifesto.html
517
+ .. [6] Peter Luschny, "An introduction to the Bernoulli function",
518
+ https://arxiv.org/abs/2009.06743
519
+
520
+ """
521
+
522
+ args: tTuple[Integer]
523
+
524
+ # Calculates B_n for positive even n
525
+ @staticmethod
526
+ def _calc_bernoulli(n):
527
+ s = 0
528
+ a = int(binomial(n + 3, n - 6))
529
+ for j in range(1, n//6 + 1):
530
+ s += a * bernoulli(n - 6*j)
531
+ # Avoid computing each binomial coefficient from scratch
532
+ a *= _product(n - 6 - 6*j + 1, n - 6*j)
533
+ a //= _product(6*j + 4, 6*j + 9)
534
+ if n % 6 == 4:
535
+ s = -Rational(n + 3, 6) - s
536
+ else:
537
+ s = Rational(n + 3, 3) - s
538
+ return s / binomial(n + 3, n)
539
+
540
+ # We implement a specialized memoization scheme to handle each
541
+ # case modulo 6 separately
542
+ _cache = {0: S.One, 2: Rational(1, 6), 4: Rational(-1, 30)}
543
+ _highest = {0: 0, 2: 2, 4: 4}
544
+
545
+ @classmethod
546
+ def eval(cls, n, x=None):
547
+ if x is S.One:
548
+ return cls(n)
549
+ elif n.is_zero:
550
+ return S.One
551
+ elif n.is_integer is False or n.is_nonnegative is False:
552
+ if x is not None and x.is_Integer and x.is_nonpositive:
553
+ return S.NaN
554
+ return
555
+ # Bernoulli numbers
556
+ elif x is None:
557
+ if n is S.One:
558
+ return S.Half
559
+ elif n.is_odd and (n-1).is_positive:
560
+ return S.Zero
561
+ elif n.is_Number:
562
+ n = int(n)
563
+ # Use mpmath for enormous Bernoulli numbers
564
+ if n > 500:
565
+ p, q = mp.bernfrac(n)
566
+ return Rational(int(p), int(q))
567
+ case = n % 6
568
+ highest_cached = cls._highest[case]
569
+ if n <= highest_cached:
570
+ return cls._cache[n]
571
+ # To avoid excessive recursion when, say, bernoulli(1000) is
572
+ # requested, calculate and cache the entire sequence ... B_988,
573
+ # B_994, B_1000 in increasing order
574
+ for i in range(highest_cached + 6, n + 6, 6):
575
+ b = cls._calc_bernoulli(i)
576
+ cls._cache[i] = b
577
+ cls._highest[case] = i
578
+ return b
579
+ # Bernoulli polynomials
580
+ elif n.is_Number:
581
+ return bernoulli_poly(n, x)
582
+
583
+ def _eval_rewrite_as_zeta(self, n, x=1, **kwargs):
584
+ from sympy.functions.special.zeta_functions import zeta
585
+ return Piecewise((1, Eq(n, 0)), (-n * zeta(1-n, x), True))
586
+
587
+ def _eval_evalf(self, prec):
588
+ if not all(x.is_number for x in self.args):
589
+ return
590
+ n = self.args[0]._to_mpmath(prec)
591
+ x = (self.args[1] if len(self.args) > 1 else S.One)._to_mpmath(prec)
592
+ with workprec(prec):
593
+ if n == 0:
594
+ res = mp.mpf(1)
595
+ elif n == 1:
596
+ res = x - mp.mpf(0.5)
597
+ elif mp.isint(n) and n >= 0:
598
+ res = mp.bernoulli(n) if x == 1 else mp.bernpoly(n, x)
599
+ else:
600
+ res = -n * mp.zeta(1-n, x)
601
+ return Expr._from_mpmath(res, prec)
602
+
603
+
604
+ #----------------------------------------------------------------------------#
605
+ # #
606
+ # Bell numbers #
607
+ # #
608
+ #----------------------------------------------------------------------------#
609
+
610
+
611
+ class bell(Function):
612
+ r"""
613
+ Bell numbers / Bell polynomials
614
+
615
+ The Bell numbers satisfy `B_0 = 1` and
616
+
617
+ .. math:: B_n = \sum_{k=0}^{n-1} \binom{n-1}{k} B_k.
618
+
619
+ They are also given by:
620
+
621
+ .. math:: B_n = \frac{1}{e} \sum_{k=0}^{\infty} \frac{k^n}{k!}.
622
+
623
+ The Bell polynomials are given by `B_0(x) = 1` and
624
+
625
+ .. math:: B_n(x) = x \sum_{k=1}^{n-1} \binom{n-1}{k-1} B_{k-1}(x).
626
+
627
+ The second kind of Bell polynomials (are sometimes called "partial" Bell
628
+ polynomials or incomplete Bell polynomials) are defined as
629
+
630
+ .. math:: B_{n,k}(x_1, x_2,\dotsc x_{n-k+1}) =
631
+ \sum_{j_1+j_2+j_2+\dotsb=k \atop j_1+2j_2+3j_2+\dotsb=n}
632
+ \frac{n!}{j_1!j_2!\dotsb j_{n-k+1}!}
633
+ \left(\frac{x_1}{1!} \right)^{j_1}
634
+ \left(\frac{x_2}{2!} \right)^{j_2} \dotsb
635
+ \left(\frac{x_{n-k+1}}{(n-k+1)!} \right) ^{j_{n-k+1}}.
636
+
637
+ * ``bell(n)`` gives the `n^{th}` Bell number, `B_n`.
638
+ * ``bell(n, x)`` gives the `n^{th}` Bell polynomial, `B_n(x)`.
639
+ * ``bell(n, k, (x1, x2, ...))`` gives Bell polynomials of the second kind,
640
+ `B_{n,k}(x_1, x_2, \dotsc, x_{n-k+1})`.
641
+
642
+ Notes
643
+ =====
644
+
645
+ Not to be confused with Bernoulli numbers and Bernoulli polynomials,
646
+ which use the same notation.
647
+
648
+ Examples
649
+ ========
650
+
651
+ >>> from sympy import bell, Symbol, symbols
652
+
653
+ >>> [bell(n) for n in range(11)]
654
+ [1, 1, 2, 5, 15, 52, 203, 877, 4140, 21147, 115975]
655
+ >>> bell(30)
656
+ 846749014511809332450147
657
+ >>> bell(4, Symbol('t'))
658
+ t**4 + 6*t**3 + 7*t**2 + t
659
+ >>> bell(6, 2, symbols('x:6')[1:])
660
+ 6*x1*x5 + 15*x2*x4 + 10*x3**2
661
+
662
+ See Also
663
+ ========
664
+
665
+ bernoulli, catalan, euler, fibonacci, harmonic, lucas, genocchi, partition, tribonacci
666
+
667
+ References
668
+ ==========
669
+
670
+ .. [1] https://en.wikipedia.org/wiki/Bell_number
671
+ .. [2] https://mathworld.wolfram.com/BellNumber.html
672
+ .. [3] https://mathworld.wolfram.com/BellPolynomial.html
673
+
674
+ """
675
+
676
+ @staticmethod
677
+ @recurrence_memo([1, 1])
678
+ def _bell(n, prev):
679
+ s = 1
680
+ a = 1
681
+ for k in range(1, n):
682
+ a = a * (n - k) // k
683
+ s += a * prev[k]
684
+ return s
685
+
686
+ @staticmethod
687
+ @recurrence_memo([S.One, _sym])
688
+ def _bell_poly(n, prev):
689
+ s = 1
690
+ a = 1
691
+ for k in range(2, n + 1):
692
+ a = a * (n - k + 1) // (k - 1)
693
+ s += a * prev[k - 1]
694
+ return expand_mul(_sym * s)
695
+
696
+ @staticmethod
697
+ def _bell_incomplete_poly(n, k, symbols):
698
+ r"""
699
+ The second kind of Bell polynomials (incomplete Bell polynomials).
700
+
701
+ Calculated by recurrence formula:
702
+
703
+ .. math:: B_{n,k}(x_1, x_2, \dotsc, x_{n-k+1}) =
704
+ \sum_{m=1}^{n-k+1}
705
+ \x_m \binom{n-1}{m-1} B_{n-m,k-1}(x_1, x_2, \dotsc, x_{n-m-k})
706
+
707
+ where
708
+ `B_{0,0} = 1;`
709
+ `B_{n,0} = 0; for n \ge 1`
710
+ `B_{0,k} = 0; for k \ge 1`
711
+
712
+ """
713
+ if (n == 0) and (k == 0):
714
+ return S.One
715
+ elif (n == 0) or (k == 0):
716
+ return S.Zero
717
+ s = S.Zero
718
+ a = S.One
719
+ for m in range(1, n - k + 2):
720
+ s += a * bell._bell_incomplete_poly(
721
+ n - m, k - 1, symbols) * symbols[m - 1]
722
+ a = a * (n - m) / m
723
+ return expand_mul(s)
724
+
725
+ @classmethod
726
+ def eval(cls, n, k_sym=None, symbols=None):
727
+ if n is S.Infinity:
728
+ if k_sym is None:
729
+ return S.Infinity
730
+ else:
731
+ raise ValueError("Bell polynomial is not defined")
732
+
733
+ if n.is_negative or n.is_integer is False:
734
+ raise ValueError("a non-negative integer expected")
735
+
736
+ if n.is_Integer and n.is_nonnegative:
737
+ if k_sym is None:
738
+ return Integer(cls._bell(int(n)))
739
+ elif symbols is None:
740
+ return cls._bell_poly(int(n)).subs(_sym, k_sym)
741
+ else:
742
+ r = cls._bell_incomplete_poly(int(n), int(k_sym), symbols)
743
+ return r
744
+
745
+ def _eval_rewrite_as_Sum(self, n, k_sym=None, symbols=None, **kwargs):
746
+ from sympy.concrete.summations import Sum
747
+ if (k_sym is not None) or (symbols is not None):
748
+ return self
749
+
750
+ # Dobinski's formula
751
+ if not n.is_nonnegative:
752
+ return self
753
+ k = Dummy('k', integer=True, nonnegative=True)
754
+ return 1 / E * Sum(k**n / factorial(k), (k, 0, S.Infinity))
755
+
756
+
757
+ #----------------------------------------------------------------------------#
758
+ # #
759
+ # Harmonic numbers #
760
+ # #
761
+ #----------------------------------------------------------------------------#
762
+
763
+
764
+ class harmonic(Function):
765
+ r"""
766
+ Harmonic numbers
767
+
768
+ The nth harmonic number is given by `\operatorname{H}_{n} =
769
+ 1 + \frac{1}{2} + \frac{1}{3} + \ldots + \frac{1}{n}`.
770
+
771
+ More generally:
772
+
773
+ .. math:: \operatorname{H}_{n,m} = \sum_{k=1}^{n} \frac{1}{k^m}
774
+
775
+ As `n \rightarrow \infty`, `\operatorname{H}_{n,m} \rightarrow \zeta(m)`,
776
+ the Riemann zeta function.
777
+
778
+ * ``harmonic(n)`` gives the nth harmonic number, `\operatorname{H}_n`
779
+
780
+ * ``harmonic(n, m)`` gives the nth generalized harmonic number
781
+ of order `m`, `\operatorname{H}_{n,m}`, where
782
+ ``harmonic(n) == harmonic(n, 1)``
783
+
784
+ This function can be extended to complex `n` and `m` where `n` is not a
785
+ negative integer or `m` is a nonpositive integer as
786
+
787
+ .. math:: \operatorname{H}_{n,m} = \begin{cases} \zeta(m) - \zeta(m, n+1)
788
+ & m \ne 1 \\ \psi(n+1) + \gamma & m = 1 \end{cases}
789
+
790
+ Examples
791
+ ========
792
+
793
+ >>> from sympy import harmonic, oo
794
+
795
+ >>> [harmonic(n) for n in range(6)]
796
+ [0, 1, 3/2, 11/6, 25/12, 137/60]
797
+ >>> [harmonic(n, 2) for n in range(6)]
798
+ [0, 1, 5/4, 49/36, 205/144, 5269/3600]
799
+ >>> harmonic(oo, 2)
800
+ pi**2/6
801
+
802
+ >>> from sympy import Symbol, Sum
803
+ >>> n = Symbol("n")
804
+
805
+ >>> harmonic(n).rewrite(Sum)
806
+ Sum(1/_k, (_k, 1, n))
807
+
808
+ We can evaluate harmonic numbers for all integral and positive
809
+ rational arguments:
810
+
811
+ >>> from sympy import S, expand_func, simplify
812
+ >>> harmonic(8)
813
+ 761/280
814
+ >>> harmonic(11)
815
+ 83711/27720
816
+
817
+ >>> H = harmonic(1/S(3))
818
+ >>> H
819
+ harmonic(1/3)
820
+ >>> He = expand_func(H)
821
+ >>> He
822
+ -log(6) - sqrt(3)*pi/6 + 2*Sum(log(sin(_k*pi/3))*cos(2*_k*pi/3), (_k, 1, 1))
823
+ + 3*Sum(1/(3*_k + 1), (_k, 0, 0))
824
+ >>> He.doit()
825
+ -log(6) - sqrt(3)*pi/6 - log(sqrt(3)/2) + 3
826
+ >>> H = harmonic(25/S(7))
827
+ >>> He = simplify(expand_func(H).doit())
828
+ >>> He
829
+ log(sin(2*pi/7)**(2*cos(16*pi/7))/(14*sin(pi/7)**(2*cos(pi/7))*cos(pi/14)**(2*sin(pi/14)))) + pi*tan(pi/14)/2 + 30247/9900
830
+ >>> He.n(40)
831
+ 1.983697455232980674869851942390639915940
832
+ >>> harmonic(25/S(7)).n(40)
833
+ 1.983697455232980674869851942390639915940
834
+
835
+ We can rewrite harmonic numbers in terms of polygamma functions:
836
+
837
+ >>> from sympy import digamma, polygamma
838
+ >>> m = Symbol("m", integer=True, positive=True)
839
+
840
+ >>> harmonic(n).rewrite(digamma)
841
+ polygamma(0, n + 1) + EulerGamma
842
+
843
+ >>> harmonic(n).rewrite(polygamma)
844
+ polygamma(0, n + 1) + EulerGamma
845
+
846
+ >>> harmonic(n,3).rewrite(polygamma)
847
+ polygamma(2, n + 1)/2 + zeta(3)
848
+
849
+ >>> simplify(harmonic(n,m).rewrite(polygamma))
850
+ Piecewise((polygamma(0, n + 1) + EulerGamma, Eq(m, 1)),
851
+ (-(-1)**m*polygamma(m - 1, n + 1)/factorial(m - 1) + zeta(m), True))
852
+
853
+ Integer offsets in the argument can be pulled out:
854
+
855
+ >>> from sympy import expand_func
856
+
857
+ >>> expand_func(harmonic(n+4))
858
+ harmonic(n) + 1/(n + 4) + 1/(n + 3) + 1/(n + 2) + 1/(n + 1)
859
+
860
+ >>> expand_func(harmonic(n-4))
861
+ harmonic(n) - 1/(n - 1) - 1/(n - 2) - 1/(n - 3) - 1/n
862
+
863
+ Some limits can be computed as well:
864
+
865
+ >>> from sympy import limit, oo
866
+
867
+ >>> limit(harmonic(n), n, oo)
868
+ oo
869
+
870
+ >>> limit(harmonic(n, 2), n, oo)
871
+ pi**2/6
872
+
873
+ >>> limit(harmonic(n, 3), n, oo)
874
+ zeta(3)
875
+
876
+ For `m > 1`, `H_{n,m}` tends to `\zeta(m)` in the limit of infinite `n`:
877
+
878
+ >>> m = Symbol("m", positive=True)
879
+ >>> limit(harmonic(n, m+1), n, oo)
880
+ zeta(m + 1)
881
+
882
+ See Also
883
+ ========
884
+
885
+ bell, bernoulli, catalan, euler, fibonacci, lucas, genocchi, partition, tribonacci
886
+
887
+ References
888
+ ==========
889
+
890
+ .. [1] https://en.wikipedia.org/wiki/Harmonic_number
891
+ .. [2] https://functions.wolfram.com/GammaBetaErf/HarmonicNumber/
892
+ .. [3] https://functions.wolfram.com/GammaBetaErf/HarmonicNumber2/
893
+
894
+ """
895
+
896
+ @classmethod
897
+ def eval(cls, n, m=None):
898
+ from sympy.functions.special.zeta_functions import zeta
899
+ if m is S.One:
900
+ return cls(n)
901
+ if m is None:
902
+ m = S.One
903
+ if n.is_zero:
904
+ return S.Zero
905
+ elif m.is_zero:
906
+ return n
907
+ elif n is S.Infinity:
908
+ if m.is_negative:
909
+ return S.NaN
910
+ elif is_le(m, S.One):
911
+ return S.Infinity
912
+ elif is_gt(m, S.One):
913
+ return zeta(m)
914
+ elif m.is_Integer and m.is_nonpositive:
915
+ return (bernoulli(1-m, n+1) - bernoulli(1-m)) / (1-m)
916
+ elif n.is_Integer:
917
+ if n.is_negative and (m.is_integer is False or m.is_nonpositive is False):
918
+ return S.ComplexInfinity if m is S.One else S.NaN
919
+ if n.is_nonnegative:
920
+ return Add(*(k**(-m) for k in range(1, int(n)+1)))
921
+
922
+ def _eval_rewrite_as_polygamma(self, n, m=S.One, **kwargs):
923
+ from sympy.functions.special.gamma_functions import gamma, polygamma
924
+ if m.is_integer and m.is_positive:
925
+ return Piecewise((polygamma(0, n+1) + S.EulerGamma, Eq(m, 1)),
926
+ (S.NegativeOne**m * (polygamma(m-1, 1) - polygamma(m-1, n+1)) /
927
+ gamma(m), True))
928
+
929
+ def _eval_rewrite_as_digamma(self, n, m=1, **kwargs):
930
+ from sympy.functions.special.gamma_functions import polygamma
931
+ return self.rewrite(polygamma)
932
+
933
+ def _eval_rewrite_as_trigamma(self, n, m=1, **kwargs):
934
+ from sympy.functions.special.gamma_functions import polygamma
935
+ return self.rewrite(polygamma)
936
+
937
+ def _eval_rewrite_as_Sum(self, n, m=None, **kwargs):
938
+ from sympy.concrete.summations import Sum
939
+ k = Dummy("k", integer=True)
940
+ if m is None:
941
+ m = S.One
942
+ return Sum(k**(-m), (k, 1, n))
943
+
944
+ def _eval_rewrite_as_zeta(self, n, m=S.One, **kwargs):
945
+ from sympy.functions.special.zeta_functions import zeta
946
+ from sympy.functions.special.gamma_functions import digamma
947
+ return Piecewise((digamma(n + 1) + S.EulerGamma, Eq(m, 1)),
948
+ (zeta(m) - zeta(m, n+1), True))
949
+
950
+ def _eval_expand_func(self, **hints):
951
+ from sympy.concrete.summations import Sum
952
+ n = self.args[0]
953
+ m = self.args[1] if len(self.args) == 2 else 1
954
+
955
+ if m == S.One:
956
+ if n.is_Add:
957
+ off = n.args[0]
958
+ nnew = n - off
959
+ if off.is_Integer and off.is_positive:
960
+ result = [S.One/(nnew + i) for i in range(off, 0, -1)] + [harmonic(nnew)]
961
+ return Add(*result)
962
+ elif off.is_Integer and off.is_negative:
963
+ result = [-S.One/(nnew + i) for i in range(0, off, -1)] + [harmonic(nnew)]
964
+ return Add(*result)
965
+
966
+ if n.is_Rational:
967
+ # Expansions for harmonic numbers at general rational arguments (u + p/q)
968
+ # Split n as u + p/q with p < q
969
+ p, q = n.as_numer_denom()
970
+ u = p // q
971
+ p = p - u * q
972
+ if u.is_nonnegative and p.is_positive and q.is_positive and p < q:
973
+ from sympy.functions.elementary.exponential import log
974
+ from sympy.functions.elementary.integers import floor
975
+ from sympy.functions.elementary.trigonometric import sin, cos, cot
976
+ k = Dummy("k")
977
+ t1 = q * Sum(1 / (q * k + p), (k, 0, u))
978
+ t2 = 2 * Sum(cos((2 * pi * p * k) / S(q)) *
979
+ log(sin((pi * k) / S(q))),
980
+ (k, 1, floor((q - 1) / S(2))))
981
+ t3 = (pi / 2) * cot((pi * p) / q) + log(2 * q)
982
+ return t1 + t2 - t3
983
+
984
+ return self
985
+
986
+ def _eval_rewrite_as_tractable(self, n, m=1, limitvar=None, **kwargs):
987
+ from sympy.functions.special.zeta_functions import zeta
988
+ from sympy.functions.special.gamma_functions import polygamma
989
+ pg = self.rewrite(polygamma)
990
+ if not isinstance(pg, harmonic):
991
+ return pg.rewrite("tractable", deep=True)
992
+ arg = m - S.One
993
+ if arg.is_nonzero:
994
+ return (zeta(m) - zeta(m, n+1)).rewrite("tractable", deep=True)
995
+
996
+ def _eval_evalf(self, prec):
997
+ if not all(x.is_number for x in self.args):
998
+ return
999
+ n = self.args[0]._to_mpmath(prec)
1000
+ m = (self.args[1] if len(self.args) > 1 else S.One)._to_mpmath(prec)
1001
+ if mp.isint(n) and n < 0:
1002
+ return S.NaN
1003
+ with workprec(prec):
1004
+ if m == 1:
1005
+ res = mp.harmonic(n)
1006
+ else:
1007
+ res = mp.zeta(m) - mp.zeta(m, n+1)
1008
+ return Expr._from_mpmath(res, prec)
1009
+
1010
+ def fdiff(self, argindex=1):
1011
+ from sympy.functions.special.zeta_functions import zeta
1012
+ if len(self.args) == 2:
1013
+ n, m = self.args
1014
+ else:
1015
+ n, m = self.args + (1,)
1016
+ if argindex == 1:
1017
+ return m * zeta(m+1, n+1)
1018
+ else:
1019
+ raise ArgumentIndexError
1020
+
1021
+
1022
+ #----------------------------------------------------------------------------#
1023
+ # #
1024
+ # Euler numbers #
1025
+ # #
1026
+ #----------------------------------------------------------------------------#
1027
+
1028
+
1029
+ class euler(Function):
1030
+ r"""
1031
+ Euler numbers / Euler polynomials / Euler function
1032
+
1033
+ The Euler numbers are given by:
1034
+
1035
+ .. math:: E_{2n} = I \sum_{k=1}^{2n+1} \sum_{j=0}^k \binom{k}{j}
1036
+ \frac{(-1)^j (k-2j)^{2n+1}}{2^k I^k k}
1037
+
1038
+ .. math:: E_{2n+1} = 0
1039
+
1040
+ Euler numbers and Euler polynomials are related by
1041
+
1042
+ .. math:: E_n = 2^n E_n\left(\frac{1}{2}\right).
1043
+
1044
+ We compute symbolic Euler polynomials using Appell sequences,
1045
+ but numerical evaluation of the Euler polynomial is computed
1046
+ more efficiently (and more accurately) using the mpmath library.
1047
+
1048
+ The Euler polynomials are special cases of the generalized Euler function,
1049
+ related to the Genocchi function as
1050
+
1051
+ .. math:: \operatorname{E}(s, a) = -\frac{\operatorname{G}(s+1, a)}{s+1}
1052
+
1053
+ with the limit of `\psi\left(\frac{a+1}{2}\right) - \psi\left(\frac{a}{2}\right)`
1054
+ being taken when `s = -1`. The (ordinary) Euler function interpolating
1055
+ the Euler numbers is then obtained as
1056
+ `\operatorname{E}(s) = 2^s \operatorname{E}\left(s, \frac{1}{2}\right)`.
1057
+
1058
+ * ``euler(n)`` gives the nth Euler number `E_n`.
1059
+ * ``euler(s)`` gives the Euler function `\operatorname{E}(s)`.
1060
+ * ``euler(n, x)`` gives the nth Euler polynomial `E_n(x)`.
1061
+ * ``euler(s, a)`` gives the generalized Euler function `\operatorname{E}(s, a)`.
1062
+
1063
+ Examples
1064
+ ========
1065
+
1066
+ >>> from sympy import euler, Symbol, S
1067
+ >>> [euler(n) for n in range(10)]
1068
+ [1, 0, -1, 0, 5, 0, -61, 0, 1385, 0]
1069
+ >>> [2**n*euler(n,1) for n in range(10)]
1070
+ [1, 1, 0, -2, 0, 16, 0, -272, 0, 7936]
1071
+ >>> n = Symbol("n")
1072
+ >>> euler(n + 2*n)
1073
+ euler(3*n)
1074
+
1075
+ >>> x = Symbol("x")
1076
+ >>> euler(n, x)
1077
+ euler(n, x)
1078
+
1079
+ >>> euler(0, x)
1080
+ 1
1081
+ >>> euler(1, x)
1082
+ x - 1/2
1083
+ >>> euler(2, x)
1084
+ x**2 - x
1085
+ >>> euler(3, x)
1086
+ x**3 - 3*x**2/2 + 1/4
1087
+ >>> euler(4, x)
1088
+ x**4 - 2*x**3 + x
1089
+
1090
+ >>> euler(12, S.Half)
1091
+ 2702765/4096
1092
+ >>> euler(12)
1093
+ 2702765
1094
+
1095
+ See Also
1096
+ ========
1097
+
1098
+ andre, bell, bernoulli, catalan, fibonacci, harmonic, lucas, genocchi,
1099
+ partition, tribonacci, sympy.polys.appellseqs.euler_poly
1100
+
1101
+ References
1102
+ ==========
1103
+
1104
+ .. [1] https://en.wikipedia.org/wiki/Euler_numbers
1105
+ .. [2] https://mathworld.wolfram.com/EulerNumber.html
1106
+ .. [3] https://en.wikipedia.org/wiki/Alternating_permutation
1107
+ .. [4] https://mathworld.wolfram.com/AlternatingPermutation.html
1108
+
1109
+ """
1110
+
1111
+ @classmethod
1112
+ def eval(cls, n, x=None):
1113
+ if n.is_zero:
1114
+ return S.One
1115
+ elif n is S.NegativeOne:
1116
+ if x is None:
1117
+ return S.Pi/2
1118
+ from sympy.functions.special.gamma_functions import digamma
1119
+ return digamma((x+1)/2) - digamma(x/2)
1120
+ elif n.is_integer is False or n.is_nonnegative is False:
1121
+ return
1122
+ # Euler numbers
1123
+ elif x is None:
1124
+ if n.is_odd and n.is_positive:
1125
+ return S.Zero
1126
+ elif n.is_Number:
1127
+ from mpmath import mp
1128
+ n = n._to_mpmath(mp.prec)
1129
+ res = mp.eulernum(n, exact=True)
1130
+ return Integer(res)
1131
+ # Euler polynomials
1132
+ elif n.is_Number:
1133
+ return euler_poly(n, x)
1134
+
1135
+ def _eval_rewrite_as_Sum(self, n, x=None, **kwargs):
1136
+ from sympy.concrete.summations import Sum
1137
+ if x is None and n.is_even:
1138
+ k = Dummy("k", integer=True)
1139
+ j = Dummy("j", integer=True)
1140
+ n = n / 2
1141
+ Em = (S.ImaginaryUnit * Sum(Sum(binomial(k, j) * (S.NegativeOne**j *
1142
+ (k - 2*j)**(2*n + 1)) /
1143
+ (2**k*S.ImaginaryUnit**k * k), (j, 0, k)), (k, 1, 2*n + 1)))
1144
+ return Em
1145
+ if x:
1146
+ k = Dummy("k", integer=True)
1147
+ return Sum(binomial(n, k)*euler(k)/2**k*(x - S.Half)**(n - k), (k, 0, n))
1148
+
1149
+ def _eval_rewrite_as_genocchi(self, n, x=None, **kwargs):
1150
+ if x is None:
1151
+ return Piecewise((S.Pi/2, Eq(n, -1)),
1152
+ (-2**n * genocchi(n+1, S.Half) / (n+1), True))
1153
+ from sympy.functions.special.gamma_functions import digamma
1154
+ return Piecewise((digamma((x+1)/2) - digamma(x/2), Eq(n, -1)),
1155
+ (-genocchi(n+1, x) / (n+1), True))
1156
+
1157
+ def _eval_evalf(self, prec):
1158
+ if not all(i.is_number for i in self.args):
1159
+ return
1160
+ from mpmath import mp
1161
+ m, x = (self.args[0], None) if len(self.args) == 1 else self.args
1162
+ m = m._to_mpmath(prec)
1163
+ if x is not None:
1164
+ x = x._to_mpmath(prec)
1165
+ with workprec(prec):
1166
+ if mp.isint(m) and m >= 0:
1167
+ res = mp.eulernum(m) if x is None else mp.eulerpoly(m, x)
1168
+ else:
1169
+ if m == -1:
1170
+ res = mp.pi if x is None else mp.digamma((x+1)/2) - mp.digamma(x/2)
1171
+ else:
1172
+ y = 0.5 if x is None else x
1173
+ res = 2 * (mp.zeta(-m, y) - 2**(m+1) * mp.zeta(-m, (y+1)/2))
1174
+ if x is None:
1175
+ res *= 2**m
1176
+ return Expr._from_mpmath(res, prec)
1177
+
1178
+
1179
+ #----------------------------------------------------------------------------#
1180
+ # #
1181
+ # Catalan numbers #
1182
+ # #
1183
+ #----------------------------------------------------------------------------#
1184
+
1185
+
1186
+ class catalan(Function):
1187
+ r"""
1188
+ Catalan numbers
1189
+
1190
+ The `n^{th}` catalan number is given by:
1191
+
1192
+ .. math :: C_n = \frac{1}{n+1} \binom{2n}{n}
1193
+
1194
+ * ``catalan(n)`` gives the `n^{th}` Catalan number, `C_n`
1195
+
1196
+ Examples
1197
+ ========
1198
+
1199
+ >>> from sympy import (Symbol, binomial, gamma, hyper,
1200
+ ... catalan, diff, combsimp, Rational, I)
1201
+
1202
+ >>> [catalan(i) for i in range(1,10)]
1203
+ [1, 2, 5, 14, 42, 132, 429, 1430, 4862]
1204
+
1205
+ >>> n = Symbol("n", integer=True)
1206
+
1207
+ >>> catalan(n)
1208
+ catalan(n)
1209
+
1210
+ Catalan numbers can be transformed into several other, identical
1211
+ expressions involving other mathematical functions
1212
+
1213
+ >>> catalan(n).rewrite(binomial)
1214
+ binomial(2*n, n)/(n + 1)
1215
+
1216
+ >>> catalan(n).rewrite(gamma)
1217
+ 4**n*gamma(n + 1/2)/(sqrt(pi)*gamma(n + 2))
1218
+
1219
+ >>> catalan(n).rewrite(hyper)
1220
+ hyper((1 - n, -n), (2,), 1)
1221
+
1222
+ For some non-integer values of n we can get closed form
1223
+ expressions by rewriting in terms of gamma functions:
1224
+
1225
+ >>> catalan(Rational(1, 2)).rewrite(gamma)
1226
+ 8/(3*pi)
1227
+
1228
+ We can differentiate the Catalan numbers C(n) interpreted as a
1229
+ continuous real function in n:
1230
+
1231
+ >>> diff(catalan(n), n)
1232
+ (polygamma(0, n + 1/2) - polygamma(0, n + 2) + log(4))*catalan(n)
1233
+
1234
+ As a more advanced example consider the following ratio
1235
+ between consecutive numbers:
1236
+
1237
+ >>> combsimp((catalan(n + 1)/catalan(n)).rewrite(binomial))
1238
+ 2*(2*n + 1)/(n + 2)
1239
+
1240
+ The Catalan numbers can be generalized to complex numbers:
1241
+
1242
+ >>> catalan(I).rewrite(gamma)
1243
+ 4**I*gamma(1/2 + I)/(sqrt(pi)*gamma(2 + I))
1244
+
1245
+ and evaluated with arbitrary precision:
1246
+
1247
+ >>> catalan(I).evalf(20)
1248
+ 0.39764993382373624267 - 0.020884341620842555705*I
1249
+
1250
+ See Also
1251
+ ========
1252
+
1253
+ andre, bell, bernoulli, euler, fibonacci, harmonic, lucas, genocchi,
1254
+ partition, tribonacci, sympy.functions.combinatorial.factorials.binomial
1255
+
1256
+ References
1257
+ ==========
1258
+
1259
+ .. [1] https://en.wikipedia.org/wiki/Catalan_number
1260
+ .. [2] https://mathworld.wolfram.com/CatalanNumber.html
1261
+ .. [3] https://functions.wolfram.com/GammaBetaErf/CatalanNumber/
1262
+ .. [4] http://geometer.org/mathcircles/catalan.pdf
1263
+
1264
+ """
1265
+
1266
+ @classmethod
1267
+ def eval(cls, n):
1268
+ from sympy.functions.special.gamma_functions import gamma
1269
+ if (n.is_Integer and n.is_nonnegative) or \
1270
+ (n.is_noninteger and n.is_negative):
1271
+ return 4**n*gamma(n + S.Half)/(gamma(S.Half)*gamma(n + 2))
1272
+
1273
+ if (n.is_integer and n.is_negative):
1274
+ if (n + 1).is_negative:
1275
+ return S.Zero
1276
+ if (n + 1).is_zero:
1277
+ return Rational(-1, 2)
1278
+
1279
+ def fdiff(self, argindex=1):
1280
+ from sympy.functions.elementary.exponential import log
1281
+ from sympy.functions.special.gamma_functions import polygamma
1282
+ n = self.args[0]
1283
+ return catalan(n)*(polygamma(0, n + S.Half) - polygamma(0, n + 2) + log(4))
1284
+
1285
+ def _eval_rewrite_as_binomial(self, n, **kwargs):
1286
+ return binomial(2*n, n)/(n + 1)
1287
+
1288
+ def _eval_rewrite_as_factorial(self, n, **kwargs):
1289
+ return factorial(2*n) / (factorial(n+1) * factorial(n))
1290
+
1291
+ def _eval_rewrite_as_gamma(self, n, piecewise=True, **kwargs):
1292
+ from sympy.functions.special.gamma_functions import gamma
1293
+ # The gamma function allows to generalize Catalan numbers to complex n
1294
+ return 4**n*gamma(n + S.Half)/(gamma(S.Half)*gamma(n + 2))
1295
+
1296
+ def _eval_rewrite_as_hyper(self, n, **kwargs):
1297
+ from sympy.functions.special.hyper import hyper
1298
+ return hyper([1 - n, -n], [2], 1)
1299
+
1300
+ def _eval_rewrite_as_Product(self, n, **kwargs):
1301
+ from sympy.concrete.products import Product
1302
+ if not (n.is_integer and n.is_nonnegative):
1303
+ return self
1304
+ k = Dummy('k', integer=True, positive=True)
1305
+ return Product((n + k) / k, (k, 2, n))
1306
+
1307
+ def _eval_is_integer(self):
1308
+ if self.args[0].is_integer and self.args[0].is_nonnegative:
1309
+ return True
1310
+
1311
+ def _eval_is_positive(self):
1312
+ if self.args[0].is_nonnegative:
1313
+ return True
1314
+
1315
+ def _eval_is_composite(self):
1316
+ if self.args[0].is_integer and (self.args[0] - 3).is_positive:
1317
+ return True
1318
+
1319
+ def _eval_evalf(self, prec):
1320
+ from sympy.functions.special.gamma_functions import gamma
1321
+ if self.args[0].is_number:
1322
+ return self.rewrite(gamma)._eval_evalf(prec)
1323
+
1324
+
1325
+ #----------------------------------------------------------------------------#
1326
+ # #
1327
+ # Genocchi numbers #
1328
+ # #
1329
+ #----------------------------------------------------------------------------#
1330
+
1331
+
1332
+ class genocchi(Function):
1333
+ r"""
1334
+ Genocchi numbers / Genocchi polynomials / Genocchi function
1335
+
1336
+ The Genocchi numbers are a sequence of integers `G_n` that satisfy the
1337
+ relation:
1338
+
1339
+ .. math:: \frac{-2t}{1 + e^{-t}} = \sum_{n=0}^\infty \frac{G_n t^n}{n!}
1340
+
1341
+ They are related to the Bernoulli numbers by
1342
+
1343
+ .. math:: G_n = 2 (1 - 2^n) B_n
1344
+
1345
+ and generalize like the Bernoulli numbers to the Genocchi polynomials and
1346
+ function as
1347
+
1348
+ .. math:: \operatorname{G}(s, a) = 2 \left(\operatorname{B}(s, a) -
1349
+ 2^s \operatorname{B}\left(s, \frac{a+1}{2}\right)\right)
1350
+
1351
+ .. versionchanged:: 1.12
1352
+ ``genocchi(1)`` gives `-1` instead of `1`.
1353
+
1354
+ Examples
1355
+ ========
1356
+
1357
+ >>> from sympy import genocchi, Symbol
1358
+ >>> [genocchi(n) for n in range(9)]
1359
+ [0, -1, -1, 0, 1, 0, -3, 0, 17]
1360
+ >>> n = Symbol('n', integer=True, positive=True)
1361
+ >>> genocchi(2*n + 1)
1362
+ 0
1363
+ >>> x = Symbol('x')
1364
+ >>> genocchi(4, x)
1365
+ -4*x**3 + 6*x**2 - 1
1366
+
1367
+ See Also
1368
+ ========
1369
+
1370
+ bell, bernoulli, catalan, euler, fibonacci, harmonic, lucas, partition, tribonacci
1371
+ sympy.polys.appellseqs.genocchi_poly
1372
+
1373
+ References
1374
+ ==========
1375
+
1376
+ .. [1] https://en.wikipedia.org/wiki/Genocchi_number
1377
+ .. [2] https://mathworld.wolfram.com/GenocchiNumber.html
1378
+ .. [3] Peter Luschny, "An introduction to the Bernoulli function",
1379
+ https://arxiv.org/abs/2009.06743
1380
+
1381
+ """
1382
+
1383
+ @classmethod
1384
+ def eval(cls, n, x=None):
1385
+ if x is S.One:
1386
+ return cls(n)
1387
+ elif n.is_integer is False or n.is_nonnegative is False:
1388
+ return
1389
+ # Genocchi numbers
1390
+ elif x is None:
1391
+ if n.is_odd and (n-1).is_positive:
1392
+ return S.Zero
1393
+ elif n.is_Number:
1394
+ return 2 * (1-S(2)**n) * bernoulli(n)
1395
+ # Genocchi polynomials
1396
+ elif n.is_Number:
1397
+ return genocchi_poly(n, x)
1398
+
1399
+ def _eval_rewrite_as_bernoulli(self, n, x=1, **kwargs):
1400
+ if x == 1 and n.is_integer and n.is_nonnegative:
1401
+ return 2 * (1-S(2)**n) * bernoulli(n)
1402
+ return 2 * (bernoulli(n, x) - 2**n * bernoulli(n, (x+1) / 2))
1403
+
1404
+ def _eval_rewrite_as_dirichlet_eta(self, n, x=1, **kwargs):
1405
+ from sympy.functions.special.zeta_functions import dirichlet_eta
1406
+ return -2*n * dirichlet_eta(1-n, x)
1407
+
1408
+ def _eval_is_integer(self):
1409
+ if len(self.args) > 1 and self.args[1] != 1:
1410
+ return
1411
+ n = self.args[0]
1412
+ if n.is_integer and n.is_nonnegative:
1413
+ return True
1414
+
1415
+ def _eval_is_negative(self):
1416
+ if len(self.args) > 1 and self.args[1] != 1:
1417
+ return
1418
+ n = self.args[0]
1419
+ if n.is_integer and n.is_nonnegative:
1420
+ if n.is_odd:
1421
+ return fuzzy_not((n-1).is_positive)
1422
+ return (n/2).is_odd
1423
+
1424
+ def _eval_is_positive(self):
1425
+ if len(self.args) > 1 and self.args[1] != 1:
1426
+ return
1427
+ n = self.args[0]
1428
+ if n.is_integer and n.is_nonnegative:
1429
+ if n.is_zero or n.is_odd:
1430
+ return False
1431
+ return (n/2).is_even
1432
+
1433
+ def _eval_is_even(self):
1434
+ if len(self.args) > 1 and self.args[1] != 1:
1435
+ return
1436
+ n = self.args[0]
1437
+ if n.is_integer and n.is_nonnegative:
1438
+ if n.is_even:
1439
+ return n.is_zero
1440
+ return (n-1).is_positive
1441
+
1442
+ def _eval_is_odd(self):
1443
+ if len(self.args) > 1 and self.args[1] != 1:
1444
+ return
1445
+ n = self.args[0]
1446
+ if n.is_integer and n.is_nonnegative:
1447
+ if n.is_even:
1448
+ return fuzzy_not(n.is_zero)
1449
+ return fuzzy_not((n-1).is_positive)
1450
+
1451
+ def _eval_is_prime(self):
1452
+ if len(self.args) > 1 and self.args[1] != 1:
1453
+ return
1454
+ n = self.args[0]
1455
+ # only G_6 = -3 and G_8 = 17 are prime,
1456
+ # but SymPy does not consider negatives as prime
1457
+ # so only n=8 is tested
1458
+ return (n-8).is_zero
1459
+
1460
+ def _eval_evalf(self, prec):
1461
+ if all(i.is_number for i in self.args):
1462
+ return self.rewrite(bernoulli)._eval_evalf(prec)
1463
+
1464
+
1465
+ #----------------------------------------------------------------------------#
1466
+ # #
1467
+ # Andre numbers #
1468
+ # #
1469
+ #----------------------------------------------------------------------------#
1470
+
1471
+
1472
+ class andre(Function):
1473
+ r"""
1474
+ Andre numbers / Andre function
1475
+
1476
+ The Andre number `\mathcal{A}_n` is Luschny's name for half the number of
1477
+ *alternating permutations* on `n` elements, where a permutation is alternating
1478
+ if adjacent elements alternately compare "greater" and "smaller" going from
1479
+ left to right. For example, `2 < 3 > 1 < 4` is an alternating permutation.
1480
+
1481
+ This sequence is A000111 in the OEIS, which assigns the names *up/down numbers*
1482
+ and *Euler zigzag numbers*. It satisfies a recurrence relation similar to that
1483
+ for the Catalan numbers, with `\mathcal{A}_0 = 1` and
1484
+
1485
+ .. math:: 2 \mathcal{A}_{n+1} = \sum_{k=0}^n \binom{n}{k} \mathcal{A}_k \mathcal{A}_{n-k}
1486
+
1487
+ The Bernoulli and Euler numbers are signed transformations of the odd- and
1488
+ even-indexed elements of this sequence respectively:
1489
+
1490
+ .. math :: \operatorname{B}_{2k} = \frac{2k \mathcal{A}_{2k-1}}{(-4)^k - (-16)^k}
1491
+
1492
+ .. math :: \operatorname{E}_{2k} = (-1)^k \mathcal{A}_{2k}
1493
+
1494
+ Like the Bernoulli and Euler numbers, the Andre numbers are interpolated by the
1495
+ entire Andre function:
1496
+
1497
+ .. math :: \mathcal{A}(s) = (-i)^{s+1} \operatorname{Li}_{-s}(i) +
1498
+ i^{s+1} \operatorname{Li}_{-s}(-i) = \\ \frac{2 \Gamma(s+1)}{(2\pi)^{s+1}}
1499
+ (\zeta(s+1, 1/4) - \zeta(s+1, 3/4) \cos{\pi s})
1500
+
1501
+ Examples
1502
+ ========
1503
+
1504
+ >>> from sympy import andre, euler, bernoulli
1505
+ >>> [andre(n) for n in range(11)]
1506
+ [1, 1, 1, 2, 5, 16, 61, 272, 1385, 7936, 50521]
1507
+ >>> [(-1)**k * andre(2*k) for k in range(7)]
1508
+ [1, -1, 5, -61, 1385, -50521, 2702765]
1509
+ >>> [euler(2*k) for k in range(7)]
1510
+ [1, -1, 5, -61, 1385, -50521, 2702765]
1511
+ >>> [andre(2*k-1) * (2*k) / ((-4)**k - (-16)**k) for k in range(1, 8)]
1512
+ [1/6, -1/30, 1/42, -1/30, 5/66, -691/2730, 7/6]
1513
+ >>> [bernoulli(2*k) for k in range(1, 8)]
1514
+ [1/6, -1/30, 1/42, -1/30, 5/66, -691/2730, 7/6]
1515
+
1516
+ See Also
1517
+ ========
1518
+
1519
+ bernoulli, catalan, euler, sympy.polys.appellseqs.andre_poly
1520
+
1521
+ References
1522
+ ==========
1523
+
1524
+ .. [1] https://en.wikipedia.org/wiki/Alternating_permutation
1525
+ .. [2] https://mathworld.wolfram.com/EulerZigzagNumber.html
1526
+ .. [3] Peter Luschny, "An introduction to the Bernoulli function",
1527
+ https://arxiv.org/abs/2009.06743
1528
+ """
1529
+
1530
+ @classmethod
1531
+ def eval(cls, n):
1532
+ if n is S.NaN:
1533
+ return S.NaN
1534
+ elif n is S.Infinity:
1535
+ return S.Infinity
1536
+ if n.is_zero:
1537
+ return S.One
1538
+ elif n == -1:
1539
+ return -log(2)
1540
+ elif n == -2:
1541
+ return -2*S.Catalan
1542
+ elif n.is_Integer:
1543
+ if n.is_nonnegative and n.is_even:
1544
+ return abs(euler(n))
1545
+ elif n.is_odd:
1546
+ from sympy.functions.special.zeta_functions import zeta
1547
+ m = -n-1
1548
+ return I**m * Rational(1-2**m, 4**m) * zeta(-n)
1549
+
1550
+ def _eval_rewrite_as_zeta(self, s, **kwargs):
1551
+ from sympy.functions.elementary.trigonometric import cos
1552
+ from sympy.functions.special.gamma_functions import gamma
1553
+ from sympy.functions.special.zeta_functions import zeta
1554
+ return 2 * gamma(s+1) / (2*pi)**(s+1) * \
1555
+ (zeta(s+1, S.One/4) - cos(pi*s) * zeta(s+1, S(3)/4))
1556
+
1557
+ def _eval_rewrite_as_polylog(self, s, **kwargs):
1558
+ from sympy.functions.special.zeta_functions import polylog
1559
+ return (-I)**(s+1) * polylog(-s, I) + I**(s+1) * polylog(-s, -I)
1560
+
1561
+ def _eval_is_integer(self):
1562
+ n = self.args[0]
1563
+ if n.is_integer and n.is_nonnegative:
1564
+ return True
1565
+
1566
+ def _eval_is_positive(self):
1567
+ if self.args[0].is_nonnegative:
1568
+ return True
1569
+
1570
+ def _eval_evalf(self, prec):
1571
+ if not self.args[0].is_number:
1572
+ return
1573
+ s = self.args[0]._to_mpmath(prec+12)
1574
+ with workprec(prec+12):
1575
+ sp, cp = mp.sinpi(s/2), mp.cospi(s/2)
1576
+ res = 2*mp.dirichlet(-s, (-sp, cp, sp, -cp))
1577
+ return Expr._from_mpmath(res, prec)
1578
+
1579
+
1580
+ #----------------------------------------------------------------------------#
1581
+ # #
1582
+ # Partition numbers #
1583
+ # #
1584
+ #----------------------------------------------------------------------------#
1585
+
1586
+ _npartition = [1, 1]
1587
+ class partition(Function):
1588
+ r"""
1589
+ Partition numbers
1590
+
1591
+ The Partition numbers are a sequence of integers `p_n` that represent the
1592
+ number of distinct ways of representing `n` as a sum of natural numbers
1593
+ (with order irrelevant). The generating function for `p_n` is given by:
1594
+
1595
+ .. math:: \sum_{n=0}^\infty p_n x^n = \prod_{k=1}^\infty (1 - x^k)^{-1}
1596
+
1597
+ Examples
1598
+ ========
1599
+
1600
+ >>> from sympy import partition, Symbol
1601
+ >>> [partition(n) for n in range(9)]
1602
+ [1, 1, 2, 3, 5, 7, 11, 15, 22]
1603
+ >>> n = Symbol('n', integer=True, negative=True)
1604
+ >>> partition(n)
1605
+ 0
1606
+
1607
+ See Also
1608
+ ========
1609
+
1610
+ bell, bernoulli, catalan, euler, fibonacci, harmonic, lucas, genocchi, tribonacci
1611
+
1612
+ References
1613
+ ==========
1614
+
1615
+ .. [1] https://en.wikipedia.org/wiki/Partition_(number_theory%29
1616
+ .. [2] https://en.wikipedia.org/wiki/Pentagonal_number_theorem
1617
+
1618
+ """
1619
+
1620
+ @staticmethod
1621
+ def _partition(n):
1622
+ L = len(_npartition)
1623
+ if n < L:
1624
+ return _npartition[n]
1625
+ # lengthen cache
1626
+ for _n in range(L, n + 1):
1627
+ v, p, i = 0, 0, 0
1628
+ while 1:
1629
+ s = 0
1630
+ p += 3*i + 1 # p = pentagonal number: 1, 5, 12, ...
1631
+ if _n >= p:
1632
+ s += _npartition[_n - p]
1633
+ i += 1
1634
+ gp = p + i # gp = generalized pentagonal: 2, 7, 15, ...
1635
+ if _n >= gp:
1636
+ s += _npartition[_n - gp]
1637
+ if s == 0:
1638
+ break
1639
+ else:
1640
+ v += s if i%2 == 1 else -s
1641
+ _npartition.append(v)
1642
+ return v
1643
+
1644
+ @classmethod
1645
+ def eval(cls, n):
1646
+ is_int = n.is_integer
1647
+ if is_int == False:
1648
+ raise ValueError("Partition numbers are defined only for "
1649
+ "integers")
1650
+ elif is_int:
1651
+ if n.is_negative:
1652
+ return S.Zero
1653
+
1654
+ if n.is_zero or (n - 1).is_zero:
1655
+ return S.One
1656
+
1657
+ if n.is_Integer:
1658
+ return Integer(cls._partition(n))
1659
+
1660
+
1661
+ def _eval_is_integer(self):
1662
+ if self.args[0].is_integer:
1663
+ return True
1664
+
1665
+ def _eval_is_negative(self):
1666
+ if self.args[0].is_integer:
1667
+ return False
1668
+
1669
+ def _eval_is_positive(self):
1670
+ n = self.args[0]
1671
+ if n.is_nonnegative and n.is_integer:
1672
+ return True
1673
+
1674
+
1675
+ #######################################################################
1676
+ ###
1677
+ ### Functions for enumerating partitions, permutations and combinations
1678
+ ###
1679
+ #######################################################################
1680
+
1681
+
1682
+ class _MultisetHistogram(tuple):
1683
+ pass
1684
+
1685
+
1686
+ _N = -1
1687
+ _ITEMS = -2
1688
+ _M = slice(None, _ITEMS)
1689
+
1690
+
1691
+ def _multiset_histogram(n):
1692
+ """Return tuple used in permutation and combination counting. Input
1693
+ is a dictionary giving items with counts as values or a sequence of
1694
+ items (which need not be sorted).
1695
+
1696
+ The data is stored in a class deriving from tuple so it is easily
1697
+ recognized and so it can be converted easily to a list.
1698
+ """
1699
+ if isinstance(n, dict): # item: count
1700
+ if not all(isinstance(v, int) and v >= 0 for v in n.values()):
1701
+ raise ValueError
1702
+ tot = sum(n.values())
1703
+ items = sum(1 for k in n if n[k] > 0)
1704
+ return _MultisetHistogram([n[k] for k in n if n[k] > 0] + [items, tot])
1705
+ else:
1706
+ n = list(n)
1707
+ s = set(n)
1708
+ lens = len(s)
1709
+ lenn = len(n)
1710
+ if lens == lenn:
1711
+ n = [1]*lenn + [lenn, lenn]
1712
+ return _MultisetHistogram(n)
1713
+ m = dict(zip(s, range(lens)))
1714
+ d = dict(zip(range(lens), (0,)*lens))
1715
+ for i in n:
1716
+ d[m[i]] += 1
1717
+ return _multiset_histogram(d)
1718
+
1719
+
1720
+ def nP(n, k=None, replacement=False):
1721
+ """Return the number of permutations of ``n`` items taken ``k`` at a time.
1722
+
1723
+ Possible values for ``n``:
1724
+
1725
+ integer - set of length ``n``
1726
+
1727
+ sequence - converted to a multiset internally
1728
+
1729
+ multiset - {element: multiplicity}
1730
+
1731
+ If ``k`` is None then the total of all permutations of length 0
1732
+ through the number of items represented by ``n`` will be returned.
1733
+
1734
+ If ``replacement`` is True then a given item can appear more than once
1735
+ in the ``k`` items. (For example, for 'ab' permutations of 2 would
1736
+ include 'aa', 'ab', 'ba' and 'bb'.) The multiplicity of elements in
1737
+ ``n`` is ignored when ``replacement`` is True but the total number
1738
+ of elements is considered since no element can appear more times than
1739
+ the number of elements in ``n``.
1740
+
1741
+ Examples
1742
+ ========
1743
+
1744
+ >>> from sympy.functions.combinatorial.numbers import nP
1745
+ >>> from sympy.utilities.iterables import multiset_permutations, multiset
1746
+ >>> nP(3, 2)
1747
+ 6
1748
+ >>> nP('abc', 2) == nP(multiset('abc'), 2) == 6
1749
+ True
1750
+ >>> nP('aab', 2)
1751
+ 3
1752
+ >>> nP([1, 2, 2], 2)
1753
+ 3
1754
+ >>> [nP(3, i) for i in range(4)]
1755
+ [1, 3, 6, 6]
1756
+ >>> nP(3) == sum(_)
1757
+ True
1758
+
1759
+ When ``replacement`` is True, each item can have multiplicity
1760
+ equal to the length represented by ``n``:
1761
+
1762
+ >>> nP('aabc', replacement=True)
1763
+ 121
1764
+ >>> [len(list(multiset_permutations('aaaabbbbcccc', i))) for i in range(5)]
1765
+ [1, 3, 9, 27, 81]
1766
+ >>> sum(_)
1767
+ 121
1768
+
1769
+ See Also
1770
+ ========
1771
+ sympy.utilities.iterables.multiset_permutations
1772
+
1773
+ References
1774
+ ==========
1775
+
1776
+ .. [1] https://en.wikipedia.org/wiki/Permutation
1777
+
1778
+ """
1779
+ try:
1780
+ n = as_int(n)
1781
+ except ValueError:
1782
+ return Integer(_nP(_multiset_histogram(n), k, replacement))
1783
+ return Integer(_nP(n, k, replacement))
1784
+
1785
+
1786
+ @cacheit
1787
+ def _nP(n, k=None, replacement=False):
1788
+
1789
+ if k == 0:
1790
+ return 1
1791
+ if isinstance(n, SYMPY_INTS): # n different items
1792
+ # assert n >= 0
1793
+ if k is None:
1794
+ return sum(_nP(n, i, replacement) for i in range(n + 1))
1795
+ elif replacement:
1796
+ return n**k
1797
+ elif k > n:
1798
+ return 0
1799
+ elif k == n:
1800
+ return factorial(k)
1801
+ elif k == 1:
1802
+ return n
1803
+ else:
1804
+ # assert k >= 0
1805
+ return _product(n - k + 1, n)
1806
+ elif isinstance(n, _MultisetHistogram):
1807
+ if k is None:
1808
+ return sum(_nP(n, i, replacement) for i in range(n[_N] + 1))
1809
+ elif replacement:
1810
+ return n[_ITEMS]**k
1811
+ elif k == n[_N]:
1812
+ return factorial(k)/prod([factorial(i) for i in n[_M] if i > 1])
1813
+ elif k > n[_N]:
1814
+ return 0
1815
+ elif k == 1:
1816
+ return n[_ITEMS]
1817
+ else:
1818
+ # assert k >= 0
1819
+ tot = 0
1820
+ n = list(n)
1821
+ for i in range(len(n[_M])):
1822
+ if not n[i]:
1823
+ continue
1824
+ n[_N] -= 1
1825
+ if n[i] == 1:
1826
+ n[i] = 0
1827
+ n[_ITEMS] -= 1
1828
+ tot += _nP(_MultisetHistogram(n), k - 1)
1829
+ n[_ITEMS] += 1
1830
+ n[i] = 1
1831
+ else:
1832
+ n[i] -= 1
1833
+ tot += _nP(_MultisetHistogram(n), k - 1)
1834
+ n[i] += 1
1835
+ n[_N] += 1
1836
+ return tot
1837
+
1838
+
1839
+ @cacheit
1840
+ def _AOP_product(n):
1841
+ """for n = (m1, m2, .., mk) return the coefficients of the polynomial,
1842
+ prod(sum(x**i for i in range(nj + 1)) for nj in n); i.e. the coefficients
1843
+ of the product of AOPs (all-one polynomials) or order given in n. The
1844
+ resulting coefficient corresponding to x**r is the number of r-length
1845
+ combinations of sum(n) elements with multiplicities given in n.
1846
+ The coefficients are given as a default dictionary (so if a query is made
1847
+ for a key that is not present, 0 will be returned).
1848
+
1849
+ Examples
1850
+ ========
1851
+
1852
+ >>> from sympy.functions.combinatorial.numbers import _AOP_product
1853
+ >>> from sympy.abc import x
1854
+ >>> n = (2, 2, 3) # e.g. aabbccc
1855
+ >>> prod = ((x**2 + x + 1)*(x**2 + x + 1)*(x**3 + x**2 + x + 1)).expand()
1856
+ >>> c = _AOP_product(n); dict(c)
1857
+ {0: 1, 1: 3, 2: 6, 3: 8, 4: 8, 5: 6, 6: 3, 7: 1}
1858
+ >>> [c[i] for i in range(8)] == [prod.coeff(x, i) for i in range(8)]
1859
+ True
1860
+
1861
+ The generating poly used here is the same as that listed in
1862
+ https://tinyurl.com/cep849r, but in a refactored form.
1863
+
1864
+ """
1865
+
1866
+ n = list(n)
1867
+ ord = sum(n)
1868
+ need = (ord + 2)//2
1869
+ rv = [1]*(n.pop() + 1)
1870
+ rv.extend((0,) * (need - len(rv)))
1871
+ rv = rv[:need]
1872
+ while n:
1873
+ ni = n.pop()
1874
+ N = ni + 1
1875
+ was = rv[:]
1876
+ for i in range(1, min(N, len(rv))):
1877
+ rv[i] += rv[i - 1]
1878
+ for i in range(N, need):
1879
+ rv[i] += rv[i - 1] - was[i - N]
1880
+ rev = list(reversed(rv))
1881
+ if ord % 2:
1882
+ rv = rv + rev
1883
+ else:
1884
+ rv[-1:] = rev
1885
+ d = defaultdict(int)
1886
+ for i, r in enumerate(rv):
1887
+ d[i] = r
1888
+ return d
1889
+
1890
+
1891
+ def nC(n, k=None, replacement=False):
1892
+ """Return the number of combinations of ``n`` items taken ``k`` at a time.
1893
+
1894
+ Possible values for ``n``:
1895
+
1896
+ integer - set of length ``n``
1897
+
1898
+ sequence - converted to a multiset internally
1899
+
1900
+ multiset - {element: multiplicity}
1901
+
1902
+ If ``k`` is None then the total of all combinations of length 0
1903
+ through the number of items represented in ``n`` will be returned.
1904
+
1905
+ If ``replacement`` is True then a given item can appear more than once
1906
+ in the ``k`` items. (For example, for 'ab' sets of 2 would include 'aa',
1907
+ 'ab', and 'bb'.) The multiplicity of elements in ``n`` is ignored when
1908
+ ``replacement`` is True but the total number of elements is considered
1909
+ since no element can appear more times than the number of elements in
1910
+ ``n``.
1911
+
1912
+ Examples
1913
+ ========
1914
+
1915
+ >>> from sympy.functions.combinatorial.numbers import nC
1916
+ >>> from sympy.utilities.iterables import multiset_combinations
1917
+ >>> nC(3, 2)
1918
+ 3
1919
+ >>> nC('abc', 2)
1920
+ 3
1921
+ >>> nC('aab', 2)
1922
+ 2
1923
+
1924
+ When ``replacement`` is True, each item can have multiplicity
1925
+ equal to the length represented by ``n``:
1926
+
1927
+ >>> nC('aabc', replacement=True)
1928
+ 35
1929
+ >>> [len(list(multiset_combinations('aaaabbbbcccc', i))) for i in range(5)]
1930
+ [1, 3, 6, 10, 15]
1931
+ >>> sum(_)
1932
+ 35
1933
+
1934
+ If there are ``k`` items with multiplicities ``m_1, m_2, ..., m_k``
1935
+ then the total of all combinations of length 0 through ``k`` is the
1936
+ product, ``(m_1 + 1)*(m_2 + 1)*...*(m_k + 1)``. When the multiplicity
1937
+ of each item is 1 (i.e., k unique items) then there are 2**k
1938
+ combinations. For example, if there are 4 unique items, the total number
1939
+ of combinations is 16:
1940
+
1941
+ >>> sum(nC(4, i) for i in range(5))
1942
+ 16
1943
+
1944
+ See Also
1945
+ ========
1946
+
1947
+ sympy.utilities.iterables.multiset_combinations
1948
+
1949
+ References
1950
+ ==========
1951
+
1952
+ .. [1] https://en.wikipedia.org/wiki/Combination
1953
+ .. [2] https://tinyurl.com/cep849r
1954
+
1955
+ """
1956
+
1957
+ if isinstance(n, SYMPY_INTS):
1958
+ if k is None:
1959
+ if not replacement:
1960
+ return 2**n
1961
+ return sum(nC(n, i, replacement) for i in range(n + 1))
1962
+ if k < 0:
1963
+ raise ValueError("k cannot be negative")
1964
+ if replacement:
1965
+ return binomial(n + k - 1, k)
1966
+ return binomial(n, k)
1967
+ if isinstance(n, _MultisetHistogram):
1968
+ N = n[_N]
1969
+ if k is None:
1970
+ if not replacement:
1971
+ return prod(m + 1 for m in n[_M])
1972
+ return sum(nC(n, i, replacement) for i in range(N + 1))
1973
+ elif replacement:
1974
+ return nC(n[_ITEMS], k, replacement)
1975
+ # assert k >= 0
1976
+ elif k in (1, N - 1):
1977
+ return n[_ITEMS]
1978
+ elif k in (0, N):
1979
+ return 1
1980
+ return _AOP_product(tuple(n[_M]))[k]
1981
+ else:
1982
+ return nC(_multiset_histogram(n), k, replacement)
1983
+
1984
+
1985
+ def _eval_stirling1(n, k):
1986
+ if n == k == 0:
1987
+ return S.One
1988
+ if 0 in (n, k):
1989
+ return S.Zero
1990
+
1991
+ # some special values
1992
+ if n == k:
1993
+ return S.One
1994
+ elif k == n - 1:
1995
+ return binomial(n, 2)
1996
+ elif k == n - 2:
1997
+ return (3*n - 1)*binomial(n, 3)/4
1998
+ elif k == n - 3:
1999
+ return binomial(n, 2)*binomial(n, 4)
2000
+
2001
+ return _stirling1(n, k)
2002
+
2003
+
2004
+ @cacheit
2005
+ def _stirling1(n, k):
2006
+ row = [0, 1]+[0]*(k-1) # for n = 1
2007
+ for i in range(2, n+1):
2008
+ for j in range(min(k,i), 0, -1):
2009
+ row[j] = (i-1) * row[j] + row[j-1]
2010
+ return Integer(row[k])
2011
+
2012
+
2013
+ def _eval_stirling2(n, k):
2014
+ if n == k == 0:
2015
+ return S.One
2016
+ if 0 in (n, k):
2017
+ return S.Zero
2018
+
2019
+ # some special values
2020
+ if n == k:
2021
+ return S.One
2022
+ elif k == n - 1:
2023
+ return binomial(n, 2)
2024
+ elif k == 1:
2025
+ return S.One
2026
+ elif k == 2:
2027
+ return Integer(2**(n - 1) - 1)
2028
+
2029
+ return _stirling2(n, k)
2030
+
2031
+
2032
+ @cacheit
2033
+ def _stirling2(n, k):
2034
+ row = [0, 1]+[0]*(k-1) # for n = 1
2035
+ for i in range(2, n+1):
2036
+ for j in range(min(k,i), 0, -1):
2037
+ row[j] = j * row[j] + row[j-1]
2038
+ return Integer(row[k])
2039
+
2040
+
2041
+ def stirling(n, k, d=None, kind=2, signed=False):
2042
+ r"""Return Stirling number $S(n, k)$ of the first or second (default) kind.
2043
+
2044
+ The sum of all Stirling numbers of the second kind for $k = 1$
2045
+ through $n$ is ``bell(n)``. The recurrence relationship for these numbers
2046
+ is:
2047
+
2048
+ .. math :: {0 \brace 0} = 1; {n \brace 0} = {0 \brace k} = 0;
2049
+
2050
+ .. math :: {{n+1} \brace k} = j {n \brace k} + {n \brace {k-1}}
2051
+
2052
+ where $j$ is:
2053
+ $n$ for Stirling numbers of the first kind,
2054
+ $-n$ for signed Stirling numbers of the first kind,
2055
+ $k$ for Stirling numbers of the second kind.
2056
+
2057
+ The first kind of Stirling number counts the number of permutations of
2058
+ ``n`` distinct items that have ``k`` cycles; the second kind counts the
2059
+ ways in which ``n`` distinct items can be partitioned into ``k`` parts.
2060
+ If ``d`` is given, the "reduced Stirling number of the second kind" is
2061
+ returned: $S^{d}(n, k) = S(n - d + 1, k - d + 1)$ with $n \ge k \ge d$.
2062
+ (This counts the ways to partition $n$ consecutive integers into $k$
2063
+ groups with no pairwise difference less than $d$. See example below.)
2064
+
2065
+ To obtain the signed Stirling numbers of the first kind, use keyword
2066
+ ``signed=True``. Using this keyword automatically sets ``kind`` to 1.
2067
+
2068
+ Examples
2069
+ ========
2070
+
2071
+ >>> from sympy.functions.combinatorial.numbers import stirling, bell
2072
+ >>> from sympy.combinatorics import Permutation
2073
+ >>> from sympy.utilities.iterables import multiset_partitions, permutations
2074
+
2075
+ First kind (unsigned by default):
2076
+
2077
+ >>> [stirling(6, i, kind=1) for i in range(7)]
2078
+ [0, 120, 274, 225, 85, 15, 1]
2079
+ >>> perms = list(permutations(range(4)))
2080
+ >>> [sum(Permutation(p).cycles == i for p in perms) for i in range(5)]
2081
+ [0, 6, 11, 6, 1]
2082
+ >>> [stirling(4, i, kind=1) for i in range(5)]
2083
+ [0, 6, 11, 6, 1]
2084
+
2085
+ First kind (signed):
2086
+
2087
+ >>> [stirling(4, i, signed=True) for i in range(5)]
2088
+ [0, -6, 11, -6, 1]
2089
+
2090
+ Second kind:
2091
+
2092
+ >>> [stirling(10, i) for i in range(12)]
2093
+ [0, 1, 511, 9330, 34105, 42525, 22827, 5880, 750, 45, 1, 0]
2094
+ >>> sum(_) == bell(10)
2095
+ True
2096
+ >>> len(list(multiset_partitions(range(4), 2))) == stirling(4, 2)
2097
+ True
2098
+
2099
+ Reduced second kind:
2100
+
2101
+ >>> from sympy import subsets, oo
2102
+ >>> def delta(p):
2103
+ ... if len(p) == 1:
2104
+ ... return oo
2105
+ ... return min(abs(i[0] - i[1]) for i in subsets(p, 2))
2106
+ >>> parts = multiset_partitions(range(5), 3)
2107
+ >>> d = 2
2108
+ >>> sum(1 for p in parts if all(delta(i) >= d for i in p))
2109
+ 7
2110
+ >>> stirling(5, 3, 2)
2111
+ 7
2112
+
2113
+ See Also
2114
+ ========
2115
+ sympy.utilities.iterables.multiset_partitions
2116
+
2117
+
2118
+ References
2119
+ ==========
2120
+
2121
+ .. [1] https://en.wikipedia.org/wiki/Stirling_numbers_of_the_first_kind
2122
+ .. [2] https://en.wikipedia.org/wiki/Stirling_numbers_of_the_second_kind
2123
+
2124
+ """
2125
+ # TODO: make this a class like bell()
2126
+
2127
+ n = as_int(n)
2128
+ k = as_int(k)
2129
+ if n < 0:
2130
+ raise ValueError('n must be nonnegative')
2131
+ if k > n:
2132
+ return S.Zero
2133
+ if d:
2134
+ # assert k >= d
2135
+ # kind is ignored -- only kind=2 is supported
2136
+ return _eval_stirling2(n - d + 1, k - d + 1)
2137
+ elif signed:
2138
+ # kind is ignored -- only kind=1 is supported
2139
+ return S.NegativeOne**(n - k)*_eval_stirling1(n, k)
2140
+
2141
+ if kind == 1:
2142
+ return _eval_stirling1(n, k)
2143
+ elif kind == 2:
2144
+ return _eval_stirling2(n, k)
2145
+ else:
2146
+ raise ValueError('kind must be 1 or 2, not %s' % k)
2147
+
2148
+
2149
+ @cacheit
2150
+ def _nT(n, k):
2151
+ """Return the partitions of ``n`` items into ``k`` parts. This
2152
+ is used by ``nT`` for the case when ``n`` is an integer."""
2153
+ # really quick exits
2154
+ if k > n or k < 0:
2155
+ return 0
2156
+ if k in (1, n):
2157
+ return 1
2158
+ if k == 0:
2159
+ return 0
2160
+ # exits that could be done below but this is quicker
2161
+ if k == 2:
2162
+ return n//2
2163
+ d = n - k
2164
+ if d <= 3:
2165
+ return d
2166
+ # quick exit
2167
+ if 3*k >= n: # or, equivalently, 2*k >= d
2168
+ # all the information needed in this case
2169
+ # will be in the cache needed to calculate
2170
+ # partition(d), so...
2171
+ # update cache
2172
+ tot = partition._partition(d)
2173
+ # and correct for values not needed
2174
+ if d - k > 0:
2175
+ tot -= sum(_npartition[:d - k])
2176
+ return tot
2177
+ # regular exit
2178
+ # nT(n, k) = Sum(nT(n - k, m), (m, 1, k));
2179
+ # calculate needed nT(i, j) values
2180
+ p = [1]*d
2181
+ for i in range(2, k + 1):
2182
+ for m in range(i + 1, d):
2183
+ p[m] += p[m - i]
2184
+ d -= 1
2185
+ # if p[0] were appended to the end of p then the last
2186
+ # k values of p are the nT(n, j) values for 0 < j < k in reverse
2187
+ # order p[-1] = nT(n, 1), p[-2] = nT(n, 2), etc.... Instead of
2188
+ # putting the 1 from p[0] there, however, it is simply added to
2189
+ # the sum below which is valid for 1 < k <= n//2
2190
+ return (1 + sum(p[1 - k:]))
2191
+
2192
+
2193
+ def nT(n, k=None):
2194
+ """Return the number of ``k``-sized partitions of ``n`` items.
2195
+
2196
+ Possible values for ``n``:
2197
+
2198
+ integer - ``n`` identical items
2199
+
2200
+ sequence - converted to a multiset internally
2201
+
2202
+ multiset - {element: multiplicity}
2203
+
2204
+ Note: the convention for ``nT`` is different than that of ``nC`` and
2205
+ ``nP`` in that
2206
+ here an integer indicates ``n`` *identical* items instead of a set of
2207
+ length ``n``; this is in keeping with the ``partitions`` function which
2208
+ treats its integer-``n`` input like a list of ``n`` 1s. One can use
2209
+ ``range(n)`` for ``n`` to indicate ``n`` distinct items.
2210
+
2211
+ If ``k`` is None then the total number of ways to partition the elements
2212
+ represented in ``n`` will be returned.
2213
+
2214
+ Examples
2215
+ ========
2216
+
2217
+ >>> from sympy.functions.combinatorial.numbers import nT
2218
+
2219
+ Partitions of the given multiset:
2220
+
2221
+ >>> [nT('aabbc', i) for i in range(1, 7)]
2222
+ [1, 8, 11, 5, 1, 0]
2223
+ >>> nT('aabbc') == sum(_)
2224
+ True
2225
+
2226
+ >>> [nT("mississippi", i) for i in range(1, 12)]
2227
+ [1, 74, 609, 1521, 1768, 1224, 579, 197, 50, 9, 1]
2228
+
2229
+ Partitions when all items are identical:
2230
+
2231
+ >>> [nT(5, i) for i in range(1, 6)]
2232
+ [1, 2, 2, 1, 1]
2233
+ >>> nT('1'*5) == sum(_)
2234
+ True
2235
+
2236
+ When all items are different:
2237
+
2238
+ >>> [nT(range(5), i) for i in range(1, 6)]
2239
+ [1, 15, 25, 10, 1]
2240
+ >>> nT(range(5)) == sum(_)
2241
+ True
2242
+
2243
+ Partitions of an integer expressed as a sum of positive integers:
2244
+
2245
+ >>> from sympy import partition
2246
+ >>> partition(4)
2247
+ 5
2248
+ >>> nT(4, 1) + nT(4, 2) + nT(4, 3) + nT(4, 4)
2249
+ 5
2250
+ >>> nT('1'*4)
2251
+ 5
2252
+
2253
+ See Also
2254
+ ========
2255
+ sympy.utilities.iterables.partitions
2256
+ sympy.utilities.iterables.multiset_partitions
2257
+ sympy.functions.combinatorial.numbers.partition
2258
+
2259
+ References
2260
+ ==========
2261
+
2262
+ .. [1] https://web.archive.org/web/20210507012732/https://teaching.csse.uwa.edu.au/units/CITS7209/partition.pdf
2263
+
2264
+ """
2265
+
2266
+ if isinstance(n, SYMPY_INTS):
2267
+ # n identical items
2268
+ if k is None:
2269
+ return partition(n)
2270
+ if isinstance(k, SYMPY_INTS):
2271
+ n = as_int(n)
2272
+ k = as_int(k)
2273
+ return Integer(_nT(n, k))
2274
+ if not isinstance(n, _MultisetHistogram):
2275
+ try:
2276
+ # if n contains hashable items there is some
2277
+ # quick handling that can be done
2278
+ u = len(set(n))
2279
+ if u <= 1:
2280
+ return nT(len(n), k)
2281
+ elif u == len(n):
2282
+ n = range(u)
2283
+ raise TypeError
2284
+ except TypeError:
2285
+ n = _multiset_histogram(n)
2286
+ N = n[_N]
2287
+ if k is None and N == 1:
2288
+ return 1
2289
+ if k in (1, N):
2290
+ return 1
2291
+ if k == 2 or N == 2 and k is None:
2292
+ m, r = divmod(N, 2)
2293
+ rv = sum(nC(n, i) for i in range(1, m + 1))
2294
+ if not r:
2295
+ rv -= nC(n, m)//2
2296
+ if k is None:
2297
+ rv += 1 # for k == 1
2298
+ return rv
2299
+ if N == n[_ITEMS]:
2300
+ # all distinct
2301
+ if k is None:
2302
+ return bell(N)
2303
+ return stirling(N, k)
2304
+ m = MultisetPartitionTraverser()
2305
+ if k is None:
2306
+ return m.count_partitions(n[_M])
2307
+ # MultisetPartitionTraverser does not have a range-limited count
2308
+ # method, so need to enumerate and count
2309
+ tot = 0
2310
+ for discard in m.enum_range(n[_M], k-1, k):
2311
+ tot += 1
2312
+ return tot
2313
+
2314
+
2315
+ #-----------------------------------------------------------------------------#
2316
+ # #
2317
+ # Motzkin numbers #
2318
+ # #
2319
+ #-----------------------------------------------------------------------------#
2320
+
2321
+
2322
+ class motzkin(Function):
2323
+ """
2324
+ The nth Motzkin number is the number
2325
+ of ways of drawing non-intersecting chords
2326
+ between n points on a circle (not necessarily touching
2327
+ every point by a chord). The Motzkin numbers are named
2328
+ after Theodore Motzkin and have diverse applications
2329
+ in geometry, combinatorics and number theory.
2330
+
2331
+ Motzkin numbers are the integer sequence defined by the
2332
+ initial terms `M_0 = 1`, `M_1 = 1` and the two-term recurrence relation
2333
+ `M_n = \frac{2*n + 1}{n + 2} * M_{n-1} + \frac{3n - 3}{n + 2} * M_{n-2}`.
2334
+
2335
+
2336
+ Examples
2337
+ ========
2338
+
2339
+ >>> from sympy import motzkin
2340
+
2341
+ >>> motzkin.is_motzkin(5)
2342
+ False
2343
+ >>> motzkin.find_motzkin_numbers_in_range(2,300)
2344
+ [2, 4, 9, 21, 51, 127]
2345
+ >>> motzkin.find_motzkin_numbers_in_range(2,900)
2346
+ [2, 4, 9, 21, 51, 127, 323, 835]
2347
+ >>> motzkin.find_first_n_motzkins(10)
2348
+ [1, 1, 2, 4, 9, 21, 51, 127, 323, 835]
2349
+
2350
+
2351
+ References
2352
+ ==========
2353
+
2354
+ .. [1] https://en.wikipedia.org/wiki/Motzkin_number
2355
+ .. [2] https://mathworld.wolfram.com/MotzkinNumber.html
2356
+
2357
+ """
2358
+
2359
+ @staticmethod
2360
+ def is_motzkin(n):
2361
+ try:
2362
+ n = as_int(n)
2363
+ except ValueError:
2364
+ return False
2365
+ if n > 0:
2366
+ if n in (1, 2):
2367
+ return True
2368
+
2369
+ tn1 = 1
2370
+ tn = 2
2371
+ i = 3
2372
+ while tn < n:
2373
+ a = ((2*i + 1)*tn + (3*i - 3)*tn1)/(i + 2)
2374
+ i += 1
2375
+ tn1 = tn
2376
+ tn = a
2377
+
2378
+ if tn == n:
2379
+ return True
2380
+ else:
2381
+ return False
2382
+
2383
+ else:
2384
+ return False
2385
+
2386
+ @staticmethod
2387
+ def find_motzkin_numbers_in_range(x, y):
2388
+ if 0 <= x <= y:
2389
+ motzkins = []
2390
+ if x <= 1 <= y:
2391
+ motzkins.append(1)
2392
+ tn1 = 1
2393
+ tn = 2
2394
+ i = 3
2395
+ while tn <= y:
2396
+ if tn >= x:
2397
+ motzkins.append(tn)
2398
+ a = ((2*i + 1)*tn + (3*i - 3)*tn1)/(i + 2)
2399
+ i += 1
2400
+ tn1 = tn
2401
+ tn = int(a)
2402
+
2403
+ return motzkins
2404
+
2405
+ else:
2406
+ raise ValueError('The provided range is not valid. This condition should satisfy x <= y')
2407
+
2408
+ @staticmethod
2409
+ def find_first_n_motzkins(n):
2410
+ try:
2411
+ n = as_int(n)
2412
+ except ValueError:
2413
+ raise ValueError('The provided number must be a positive integer')
2414
+ if n < 0:
2415
+ raise ValueError('The provided number must be a positive integer')
2416
+ motzkins = [1]
2417
+ if n >= 1:
2418
+ motzkins.append(1)
2419
+ tn1 = 1
2420
+ tn = 2
2421
+ i = 3
2422
+ while i <= n:
2423
+ motzkins.append(tn)
2424
+ a = ((2*i + 1)*tn + (3*i - 3)*tn1)/(i + 2)
2425
+ i += 1
2426
+ tn1 = tn
2427
+ tn = int(a)
2428
+
2429
+ return motzkins
2430
+
2431
+ @staticmethod
2432
+ @recurrence_memo([S.One, S.One])
2433
+ def _motzkin(n, prev):
2434
+ return ((2*n + 1)*prev[-1] + (3*n - 3)*prev[-2]) // (n + 2)
2435
+
2436
+ @classmethod
2437
+ def eval(cls, n):
2438
+ try:
2439
+ n = as_int(n)
2440
+ except ValueError:
2441
+ raise ValueError('The provided number must be a positive integer')
2442
+ if n < 0:
2443
+ raise ValueError('The provided number must be a positive integer')
2444
+ return Integer(cls._motzkin(n - 1))
2445
+
2446
+
2447
+ def nD(i=None, brute=None, *, n=None, m=None):
2448
+ """return the number of derangements for: ``n`` unique items, ``i``
2449
+ items (as a sequence or multiset), or multiplicities, ``m`` given
2450
+ as a sequence or multiset.
2451
+
2452
+ Examples
2453
+ ========
2454
+
2455
+ >>> from sympy.utilities.iterables import generate_derangements as enum
2456
+ >>> from sympy.functions.combinatorial.numbers import nD
2457
+
2458
+ A derangement ``d`` of sequence ``s`` has all ``d[i] != s[i]``:
2459
+
2460
+ >>> set([''.join(i) for i in enum('abc')])
2461
+ {'bca', 'cab'}
2462
+ >>> nD('abc')
2463
+ 2
2464
+
2465
+ Input as iterable or dictionary (multiset form) is accepted:
2466
+
2467
+ >>> assert nD([1, 2, 2, 3, 3, 3]) == nD({1: 1, 2: 2, 3: 3})
2468
+
2469
+ By default, a brute-force enumeration and count of multiset permutations
2470
+ is only done if there are fewer than 9 elements. There may be cases when
2471
+ there is high multiplicity with few unique elements that will benefit
2472
+ from a brute-force enumeration, too. For this reason, the `brute`
2473
+ keyword (default None) is provided. When False, the brute-force
2474
+ enumeration will never be used. When True, it will always be used.
2475
+
2476
+ >>> nD('1111222233', brute=True)
2477
+ 44
2478
+
2479
+ For convenience, one may specify ``n`` distinct items using the
2480
+ ``n`` keyword:
2481
+
2482
+ >>> assert nD(n=3) == nD('abc') == 2
2483
+
2484
+ Since the number of derangments depends on the multiplicity of the
2485
+ elements and not the elements themselves, it may be more convenient
2486
+ to give a list or multiset of multiplicities using keyword ``m``:
2487
+
2488
+ >>> assert nD('abc') == nD(m=(1,1,1)) == nD(m={1:3}) == 2
2489
+
2490
+ """
2491
+ from sympy.integrals.integrals import integrate
2492
+ from sympy.functions.special.polynomials import laguerre
2493
+ from sympy.abc import x
2494
+ def ok(x):
2495
+ if not isinstance(x, SYMPY_INTS):
2496
+ raise TypeError('expecting integer values')
2497
+ if x < 0:
2498
+ raise ValueError('value must not be negative')
2499
+ return True
2500
+
2501
+ if (i, n, m).count(None) != 2:
2502
+ raise ValueError('enter only 1 of i, n, or m')
2503
+ if i is not None:
2504
+ if isinstance(i, SYMPY_INTS):
2505
+ raise TypeError('items must be a list or dictionary')
2506
+ if not i:
2507
+ return S.Zero
2508
+ if type(i) is not dict:
2509
+ s = list(i)
2510
+ ms = multiset(s)
2511
+ elif type(i) is dict:
2512
+ all(ok(_) for _ in i.values())
2513
+ ms = {k: v for k, v in i.items() if v}
2514
+ s = None
2515
+ if not ms:
2516
+ return S.Zero
2517
+ N = sum(ms.values())
2518
+ counts = multiset(ms.values())
2519
+ nkey = len(ms)
2520
+ elif n is not None:
2521
+ ok(n)
2522
+ if not n:
2523
+ return S.Zero
2524
+ return subfactorial(n)
2525
+ elif m is not None:
2526
+ if isinstance(m, dict):
2527
+ all(ok(i) and ok(j) for i, j in m.items())
2528
+ counts = {k: v for k, v in m.items() if k*v}
2529
+ elif iterable(m) or isinstance(m, str):
2530
+ m = list(m)
2531
+ all(ok(i) for i in m)
2532
+ counts = multiset([i for i in m if i])
2533
+ else:
2534
+ raise TypeError('expecting iterable')
2535
+ if not counts:
2536
+ return S.Zero
2537
+ N = sum(k*v for k, v in counts.items())
2538
+ nkey = sum(counts.values())
2539
+ s = None
2540
+ big = int(max(counts))
2541
+ if big == 1: # no repetition
2542
+ return subfactorial(nkey)
2543
+ nval = len(counts)
2544
+ if big*2 > N:
2545
+ return S.Zero
2546
+ if big*2 == N:
2547
+ if nkey == 2 and nval == 1:
2548
+ return S.One # aaabbb
2549
+ if nkey - 1 == big: # one element repeated
2550
+ return factorial(big) # e.g. abc part of abcddd
2551
+ if N < 9 and brute is None or brute:
2552
+ # for all possibilities, this was found to be faster
2553
+ if s is None:
2554
+ s = []
2555
+ i = 0
2556
+ for m, v in counts.items():
2557
+ for j in range(v):
2558
+ s.extend([i]*m)
2559
+ i += 1
2560
+ return Integer(sum(1 for i in multiset_derangements(s)))
2561
+ from sympy.functions.elementary.exponential import exp
2562
+ return Integer(abs(integrate(exp(-x)*Mul(*[
2563
+ laguerre(i, x)**m for i, m in counts.items()]), (x, 0, oo))))
venv/lib/python3.10/site-packages/sympy/functions/combinatorial/tests/__init__.py ADDED
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1
+ from sympy.concrete.products import Product
2
+ from sympy.core.function import expand_func
3
+ from sympy.core.mod import Mod
4
+ from sympy.core.mul import Mul
5
+ from sympy.core import EulerGamma
6
+ from sympy.core.numbers import (Float, I, Rational, nan, oo, pi, zoo)
7
+ from sympy.core.relational import Eq
8
+ from sympy.core.singleton import S
9
+ from sympy.core.symbol import (Dummy, Symbol, symbols)
10
+ from sympy.functions.combinatorial.factorials import (ff, rf, binomial, factorial, factorial2)
11
+ from sympy.functions.elementary.miscellaneous import sqrt
12
+ from sympy.functions.elementary.piecewise import Piecewise
13
+ from sympy.functions.special.gamma_functions import (gamma, polygamma)
14
+ from sympy.polys.polytools import Poly
15
+ from sympy.series.order import O
16
+ from sympy.simplify.simplify import simplify
17
+ from sympy.core.expr import unchanged
18
+ from sympy.core.function import ArgumentIndexError
19
+ from sympy.functions.combinatorial.factorials import subfactorial
20
+ from sympy.functions.special.gamma_functions import uppergamma
21
+ from sympy.testing.pytest import XFAIL, raises, slow
22
+
23
+ #Solves and Fixes Issue #10388 - This is the updated test for the same solved issue
24
+
25
+ def test_rf_eval_apply():
26
+ x, y = symbols('x,y')
27
+ n, k = symbols('n k', integer=True)
28
+ m = Symbol('m', integer=True, nonnegative=True)
29
+
30
+ assert rf(nan, y) is nan
31
+ assert rf(x, nan) is nan
32
+
33
+ assert unchanged(rf, x, y)
34
+
35
+ assert rf(oo, 0) == 1
36
+ assert rf(-oo, 0) == 1
37
+
38
+ assert rf(oo, 6) is oo
39
+ assert rf(-oo, 7) is -oo
40
+ assert rf(-oo, 6) is oo
41
+
42
+ assert rf(oo, -6) is oo
43
+ assert rf(-oo, -7) is oo
44
+
45
+ assert rf(-1, pi) == 0
46
+ assert rf(-5, 1 + I) == 0
47
+
48
+ assert unchanged(rf, -3, k)
49
+ assert unchanged(rf, x, Symbol('k', integer=False))
50
+ assert rf(-3, Symbol('k', integer=False)) == 0
51
+ assert rf(Symbol('x', negative=True, integer=True), Symbol('k', integer=False)) == 0
52
+
53
+ assert rf(x, 0) == 1
54
+ assert rf(x, 1) == x
55
+ assert rf(x, 2) == x*(x + 1)
56
+ assert rf(x, 3) == x*(x + 1)*(x + 2)
57
+ assert rf(x, 5) == x*(x + 1)*(x + 2)*(x + 3)*(x + 4)
58
+
59
+ assert rf(x, -1) == 1/(x - 1)
60
+ assert rf(x, -2) == 1/((x - 1)*(x - 2))
61
+ assert rf(x, -3) == 1/((x - 1)*(x - 2)*(x - 3))
62
+
63
+ assert rf(1, 100) == factorial(100)
64
+
65
+ assert rf(x**2 + 3*x, 2) == (x**2 + 3*x)*(x**2 + 3*x + 1)
66
+ assert isinstance(rf(x**2 + 3*x, 2), Mul)
67
+ assert rf(x**3 + x, -2) == 1/((x**3 + x - 1)*(x**3 + x - 2))
68
+
69
+ assert rf(Poly(x**2 + 3*x, x), 2) == Poly(x**4 + 8*x**3 + 19*x**2 + 12*x, x)
70
+ assert isinstance(rf(Poly(x**2 + 3*x, x), 2), Poly)
71
+ raises(ValueError, lambda: rf(Poly(x**2 + 3*x, x, y), 2))
72
+ assert rf(Poly(x**3 + x, x), -2) == 1/(x**6 - 9*x**5 + 35*x**4 - 75*x**3 + 94*x**2 - 66*x + 20)
73
+ raises(ValueError, lambda: rf(Poly(x**3 + x, x, y), -2))
74
+
75
+ assert rf(x, m).is_integer is None
76
+ assert rf(n, k).is_integer is None
77
+ assert rf(n, m).is_integer is True
78
+ assert rf(n, k + pi).is_integer is False
79
+ assert rf(n, m + pi).is_integer is False
80
+ assert rf(pi, m).is_integer is False
81
+
82
+ def check(x, k, o, n):
83
+ a, b = Dummy(), Dummy()
84
+ r = lambda x, k: o(a, b).rewrite(n).subs({a:x,b:k})
85
+ for i in range(-5,5):
86
+ for j in range(-5,5):
87
+ assert o(i, j) == r(i, j), (o, n, i, j)
88
+ check(x, k, rf, ff)
89
+ check(x, k, rf, binomial)
90
+ check(n, k, rf, factorial)
91
+ check(x, y, rf, factorial)
92
+ check(x, y, rf, binomial)
93
+
94
+ assert rf(x, k).rewrite(ff) == ff(x + k - 1, k)
95
+ assert rf(x, k).rewrite(gamma) == Piecewise(
96
+ (gamma(k + x)/gamma(x), x > 0),
97
+ ((-1)**k*gamma(1 - x)/gamma(-k - x + 1), True))
98
+ assert rf(5, k).rewrite(gamma) == gamma(k + 5)/24
99
+ assert rf(x, k).rewrite(binomial) == factorial(k)*binomial(x + k - 1, k)
100
+ assert rf(n, k).rewrite(factorial) == Piecewise(
101
+ (factorial(k + n - 1)/factorial(n - 1), n > 0),
102
+ ((-1)**k*factorial(-n)/factorial(-k - n), True))
103
+ assert rf(5, k).rewrite(factorial) == factorial(k + 4)/24
104
+ assert rf(x, y).rewrite(factorial) == rf(x, y)
105
+ assert rf(x, y).rewrite(binomial) == rf(x, y)
106
+
107
+ import random
108
+ from mpmath import rf as mpmath_rf
109
+ for i in range(100):
110
+ x = -500 + 500 * random.random()
111
+ k = -500 + 500 * random.random()
112
+ assert (abs(mpmath_rf(x, k) - rf(x, k)) < 10**(-15))
113
+
114
+
115
+ def test_ff_eval_apply():
116
+ x, y = symbols('x,y')
117
+ n, k = symbols('n k', integer=True)
118
+ m = Symbol('m', integer=True, nonnegative=True)
119
+
120
+ assert ff(nan, y) is nan
121
+ assert ff(x, nan) is nan
122
+
123
+ assert unchanged(ff, x, y)
124
+
125
+ assert ff(oo, 0) == 1
126
+ assert ff(-oo, 0) == 1
127
+
128
+ assert ff(oo, 6) is oo
129
+ assert ff(-oo, 7) is -oo
130
+ assert ff(-oo, 6) is oo
131
+
132
+ assert ff(oo, -6) is oo
133
+ assert ff(-oo, -7) is oo
134
+
135
+ assert ff(x, 0) == 1
136
+ assert ff(x, 1) == x
137
+ assert ff(x, 2) == x*(x - 1)
138
+ assert ff(x, 3) == x*(x - 1)*(x - 2)
139
+ assert ff(x, 5) == x*(x - 1)*(x - 2)*(x - 3)*(x - 4)
140
+
141
+ assert ff(x, -1) == 1/(x + 1)
142
+ assert ff(x, -2) == 1/((x + 1)*(x + 2))
143
+ assert ff(x, -3) == 1/((x + 1)*(x + 2)*(x + 3))
144
+
145
+ assert ff(100, 100) == factorial(100)
146
+
147
+ assert ff(2*x**2 - 5*x, 2) == (2*x**2 - 5*x)*(2*x**2 - 5*x - 1)
148
+ assert isinstance(ff(2*x**2 - 5*x, 2), Mul)
149
+ assert ff(x**2 + 3*x, -2) == 1/((x**2 + 3*x + 1)*(x**2 + 3*x + 2))
150
+
151
+ assert ff(Poly(2*x**2 - 5*x, x), 2) == Poly(4*x**4 - 28*x**3 + 59*x**2 - 35*x, x)
152
+ assert isinstance(ff(Poly(2*x**2 - 5*x, x), 2), Poly)
153
+ raises(ValueError, lambda: ff(Poly(2*x**2 - 5*x, x, y), 2))
154
+ assert ff(Poly(x**2 + 3*x, x), -2) == 1/(x**4 + 12*x**3 + 49*x**2 + 78*x + 40)
155
+ raises(ValueError, lambda: ff(Poly(x**2 + 3*x, x, y), -2))
156
+
157
+
158
+ assert ff(x, m).is_integer is None
159
+ assert ff(n, k).is_integer is None
160
+ assert ff(n, m).is_integer is True
161
+ assert ff(n, k + pi).is_integer is False
162
+ assert ff(n, m + pi).is_integer is False
163
+ assert ff(pi, m).is_integer is False
164
+
165
+ assert isinstance(ff(x, x), ff)
166
+ assert ff(n, n) == factorial(n)
167
+
168
+ def check(x, k, o, n):
169
+ a, b = Dummy(), Dummy()
170
+ r = lambda x, k: o(a, b).rewrite(n).subs({a:x,b:k})
171
+ for i in range(-5,5):
172
+ for j in range(-5,5):
173
+ assert o(i, j) == r(i, j), (o, n)
174
+ check(x, k, ff, rf)
175
+ check(x, k, ff, gamma)
176
+ check(n, k, ff, factorial)
177
+ check(x, k, ff, binomial)
178
+ check(x, y, ff, factorial)
179
+ check(x, y, ff, binomial)
180
+
181
+ assert ff(x, k).rewrite(rf) == rf(x - k + 1, k)
182
+ assert ff(x, k).rewrite(gamma) == Piecewise(
183
+ (gamma(x + 1)/gamma(-k + x + 1), x >= 0),
184
+ ((-1)**k*gamma(k - x)/gamma(-x), True))
185
+ assert ff(5, k).rewrite(gamma) == 120/gamma(6 - k)
186
+ assert ff(n, k).rewrite(factorial) == Piecewise(
187
+ (factorial(n)/factorial(-k + n), n >= 0),
188
+ ((-1)**k*factorial(k - n - 1)/factorial(-n - 1), True))
189
+ assert ff(5, k).rewrite(factorial) == 120/factorial(5 - k)
190
+ assert ff(x, k).rewrite(binomial) == factorial(k) * binomial(x, k)
191
+ assert ff(x, y).rewrite(factorial) == ff(x, y)
192
+ assert ff(x, y).rewrite(binomial) == ff(x, y)
193
+
194
+ import random
195
+ from mpmath import ff as mpmath_ff
196
+ for i in range(100):
197
+ x = -500 + 500 * random.random()
198
+ k = -500 + 500 * random.random()
199
+ a = mpmath_ff(x, k)
200
+ b = ff(x, k)
201
+ assert (abs(a - b) < abs(a) * 10**(-15))
202
+
203
+
204
+ def test_rf_ff_eval_hiprec():
205
+ maple = Float('6.9109401292234329956525265438452')
206
+ us = ff(18, Rational(2, 3)).evalf(32)
207
+ assert abs(us - maple)/us < 1e-31
208
+
209
+ maple = Float('6.8261540131125511557924466355367')
210
+ us = rf(18, Rational(2, 3)).evalf(32)
211
+ assert abs(us - maple)/us < 1e-31
212
+
213
+ maple = Float('34.007346127440197150854651814225')
214
+ us = rf(Float('4.4', 32), Float('2.2', 32));
215
+ assert abs(us - maple)/us < 1e-31
216
+
217
+
218
+ def test_rf_lambdify_mpmath():
219
+ from sympy.utilities.lambdify import lambdify
220
+ x, y = symbols('x,y')
221
+ f = lambdify((x,y), rf(x, y), 'mpmath')
222
+ maple = Float('34.007346127440197')
223
+ us = f(4.4, 2.2)
224
+ assert abs(us - maple)/us < 1e-15
225
+
226
+
227
+ def test_factorial():
228
+ x = Symbol('x')
229
+ n = Symbol('n', integer=True)
230
+ k = Symbol('k', integer=True, nonnegative=True)
231
+ r = Symbol('r', integer=False)
232
+ s = Symbol('s', integer=False, negative=True)
233
+ t = Symbol('t', nonnegative=True)
234
+ u = Symbol('u', noninteger=True)
235
+
236
+ assert factorial(-2) is zoo
237
+ assert factorial(0) == 1
238
+ assert factorial(7) == 5040
239
+ assert factorial(19) == 121645100408832000
240
+ assert factorial(31) == 8222838654177922817725562880000000
241
+ assert factorial(n).func == factorial
242
+ assert factorial(2*n).func == factorial
243
+
244
+ assert factorial(x).is_integer is None
245
+ assert factorial(n).is_integer is None
246
+ assert factorial(k).is_integer
247
+ assert factorial(r).is_integer is None
248
+
249
+ assert factorial(n).is_positive is None
250
+ assert factorial(k).is_positive
251
+
252
+ assert factorial(x).is_real is None
253
+ assert factorial(n).is_real is None
254
+ assert factorial(k).is_real is True
255
+ assert factorial(r).is_real is None
256
+ assert factorial(s).is_real is True
257
+ assert factorial(t).is_real is True
258
+ assert factorial(u).is_real is True
259
+
260
+ assert factorial(x).is_composite is None
261
+ assert factorial(n).is_composite is None
262
+ assert factorial(k).is_composite is None
263
+ assert factorial(k + 3).is_composite is True
264
+ assert factorial(r).is_composite is None
265
+ assert factorial(s).is_composite is None
266
+ assert factorial(t).is_composite is None
267
+ assert factorial(u).is_composite is None
268
+
269
+ assert factorial(oo) is oo
270
+
271
+
272
+ def test_factorial_Mod():
273
+ pr = Symbol('pr', prime=True)
274
+ p, q = 10**9 + 9, 10**9 + 33 # prime modulo
275
+ r, s = 10**7 + 5, 33333333 # composite modulo
276
+ assert Mod(factorial(pr - 1), pr) == pr - 1
277
+ assert Mod(factorial(pr - 1), -pr) == -1
278
+ assert Mod(factorial(r - 1, evaluate=False), r) == 0
279
+ assert Mod(factorial(s - 1, evaluate=False), s) == 0
280
+ assert Mod(factorial(p - 1, evaluate=False), p) == p - 1
281
+ assert Mod(factorial(q - 1, evaluate=False), q) == q - 1
282
+ assert Mod(factorial(p - 50, evaluate=False), p) == 854928834
283
+ assert Mod(factorial(q - 1800, evaluate=False), q) == 905504050
284
+ assert Mod(factorial(153, evaluate=False), r) == Mod(factorial(153), r)
285
+ assert Mod(factorial(255, evaluate=False), s) == Mod(factorial(255), s)
286
+ assert Mod(factorial(4, evaluate=False), 3) == S.Zero
287
+ assert Mod(factorial(5, evaluate=False), 6) == S.Zero
288
+
289
+
290
+ def test_factorial_diff():
291
+ n = Symbol('n', integer=True)
292
+
293
+ assert factorial(n).diff(n) == \
294
+ gamma(1 + n)*polygamma(0, 1 + n)
295
+ assert factorial(n**2).diff(n) == \
296
+ 2*n*gamma(1 + n**2)*polygamma(0, 1 + n**2)
297
+ raises(ArgumentIndexError, lambda: factorial(n**2).fdiff(2))
298
+
299
+
300
+ def test_factorial_series():
301
+ n = Symbol('n', integer=True)
302
+
303
+ assert factorial(n).series(n, 0, 3) == \
304
+ 1 - n*EulerGamma + n**2*(EulerGamma**2/2 + pi**2/12) + O(n**3)
305
+
306
+
307
+ def test_factorial_rewrite():
308
+ n = Symbol('n', integer=True)
309
+ k = Symbol('k', integer=True, nonnegative=True)
310
+
311
+ assert factorial(n).rewrite(gamma) == gamma(n + 1)
312
+ _i = Dummy('i')
313
+ assert factorial(k).rewrite(Product).dummy_eq(Product(_i, (_i, 1, k)))
314
+ assert factorial(n).rewrite(Product) == factorial(n)
315
+
316
+
317
+ def test_factorial2():
318
+ n = Symbol('n', integer=True)
319
+
320
+ assert factorial2(-1) == 1
321
+ assert factorial2(0) == 1
322
+ assert factorial2(7) == 105
323
+ assert factorial2(8) == 384
324
+
325
+ # The following is exhaustive
326
+ tt = Symbol('tt', integer=True, nonnegative=True)
327
+ tte = Symbol('tte', even=True, nonnegative=True)
328
+ tpe = Symbol('tpe', even=True, positive=True)
329
+ tto = Symbol('tto', odd=True, nonnegative=True)
330
+ tf = Symbol('tf', integer=True, nonnegative=False)
331
+ tfe = Symbol('tfe', even=True, nonnegative=False)
332
+ tfo = Symbol('tfo', odd=True, nonnegative=False)
333
+ ft = Symbol('ft', integer=False, nonnegative=True)
334
+ ff = Symbol('ff', integer=False, nonnegative=False)
335
+ fn = Symbol('fn', integer=False)
336
+ nt = Symbol('nt', nonnegative=True)
337
+ nf = Symbol('nf', nonnegative=False)
338
+ nn = Symbol('nn')
339
+ z = Symbol('z', zero=True)
340
+ #Solves and Fixes Issue #10388 - This is the updated test for the same solved issue
341
+ raises(ValueError, lambda: factorial2(oo))
342
+ raises(ValueError, lambda: factorial2(Rational(5, 2)))
343
+ raises(ValueError, lambda: factorial2(-4))
344
+ assert factorial2(n).is_integer is None
345
+ assert factorial2(tt - 1).is_integer
346
+ assert factorial2(tte - 1).is_integer
347
+ assert factorial2(tpe - 3).is_integer
348
+ assert factorial2(tto - 4).is_integer
349
+ assert factorial2(tto - 2).is_integer
350
+ assert factorial2(tf).is_integer is None
351
+ assert factorial2(tfe).is_integer is None
352
+ assert factorial2(tfo).is_integer is None
353
+ assert factorial2(ft).is_integer is None
354
+ assert factorial2(ff).is_integer is None
355
+ assert factorial2(fn).is_integer is None
356
+ assert factorial2(nt).is_integer is None
357
+ assert factorial2(nf).is_integer is None
358
+ assert factorial2(nn).is_integer is None
359
+
360
+ assert factorial2(n).is_positive is None
361
+ assert factorial2(tt - 1).is_positive is True
362
+ assert factorial2(tte - 1).is_positive is True
363
+ assert factorial2(tpe - 3).is_positive is True
364
+ assert factorial2(tpe - 1).is_positive is True
365
+ assert factorial2(tto - 2).is_positive is True
366
+ assert factorial2(tto - 1).is_positive is True
367
+ assert factorial2(tf).is_positive is None
368
+ assert factorial2(tfe).is_positive is None
369
+ assert factorial2(tfo).is_positive is None
370
+ assert factorial2(ft).is_positive is None
371
+ assert factorial2(ff).is_positive is None
372
+ assert factorial2(fn).is_positive is None
373
+ assert factorial2(nt).is_positive is None
374
+ assert factorial2(nf).is_positive is None
375
+ assert factorial2(nn).is_positive is None
376
+
377
+ assert factorial2(tt).is_even is None
378
+ assert factorial2(tt).is_odd is None
379
+ assert factorial2(tte).is_even is None
380
+ assert factorial2(tte).is_odd is None
381
+ assert factorial2(tte + 2).is_even is True
382
+ assert factorial2(tpe).is_even is True
383
+ assert factorial2(tpe).is_odd is False
384
+ assert factorial2(tto).is_odd is True
385
+ assert factorial2(tf).is_even is None
386
+ assert factorial2(tf).is_odd is None
387
+ assert factorial2(tfe).is_even is None
388
+ assert factorial2(tfe).is_odd is None
389
+ assert factorial2(tfo).is_even is False
390
+ assert factorial2(tfo).is_odd is None
391
+ assert factorial2(z).is_even is False
392
+ assert factorial2(z).is_odd is True
393
+
394
+
395
+ def test_factorial2_rewrite():
396
+ n = Symbol('n', integer=True)
397
+ assert factorial2(n).rewrite(gamma) == \
398
+ 2**(n/2)*Piecewise((1, Eq(Mod(n, 2), 0)), (sqrt(2)/sqrt(pi), Eq(Mod(n, 2), 1)))*gamma(n/2 + 1)
399
+ assert factorial2(2*n).rewrite(gamma) == 2**n*gamma(n + 1)
400
+ assert factorial2(2*n + 1).rewrite(gamma) == \
401
+ sqrt(2)*2**(n + S.Half)*gamma(n + Rational(3, 2))/sqrt(pi)
402
+
403
+
404
+ def test_binomial():
405
+ x = Symbol('x')
406
+ n = Symbol('n', integer=True)
407
+ nz = Symbol('nz', integer=True, nonzero=True)
408
+ k = Symbol('k', integer=True)
409
+ kp = Symbol('kp', integer=True, positive=True)
410
+ kn = Symbol('kn', integer=True, negative=True)
411
+ u = Symbol('u', negative=True)
412
+ v = Symbol('v', nonnegative=True)
413
+ p = Symbol('p', positive=True)
414
+ z = Symbol('z', zero=True)
415
+ nt = Symbol('nt', integer=False)
416
+ kt = Symbol('kt', integer=False)
417
+ a = Symbol('a', integer=True, nonnegative=True)
418
+ b = Symbol('b', integer=True, nonnegative=True)
419
+
420
+ assert binomial(0, 0) == 1
421
+ assert binomial(1, 1) == 1
422
+ assert binomial(10, 10) == 1
423
+ assert binomial(n, z) == 1
424
+ assert binomial(1, 2) == 0
425
+ assert binomial(-1, 2) == 1
426
+ assert binomial(1, -1) == 0
427
+ assert binomial(-1, 1) == -1
428
+ assert binomial(-1, -1) == 0
429
+ assert binomial(S.Half, S.Half) == 1
430
+ assert binomial(-10, 1) == -10
431
+ assert binomial(-10, 7) == -11440
432
+ assert binomial(n, -1) == 0 # holds for all integers (negative, zero, positive)
433
+ assert binomial(kp, -1) == 0
434
+ assert binomial(nz, 0) == 1
435
+ assert expand_func(binomial(n, 1)) == n
436
+ assert expand_func(binomial(n, 2)) == n*(n - 1)/2
437
+ assert expand_func(binomial(n, n - 2)) == n*(n - 1)/2
438
+ assert expand_func(binomial(n, n - 1)) == n
439
+ assert binomial(n, 3).func == binomial
440
+ assert binomial(n, 3).expand(func=True) == n**3/6 - n**2/2 + n/3
441
+ assert expand_func(binomial(n, 3)) == n*(n - 2)*(n - 1)/6
442
+ assert binomial(n, n).func == binomial # e.g. (-1, -1) == 0, (2, 2) == 1
443
+ assert binomial(n, n + 1).func == binomial # e.g. (-1, 0) == 1
444
+ assert binomial(kp, kp + 1) == 0
445
+ assert binomial(kn, kn) == 0 # issue #14529
446
+ assert binomial(n, u).func == binomial
447
+ assert binomial(kp, u).func == binomial
448
+ assert binomial(n, p).func == binomial
449
+ assert binomial(n, k).func == binomial
450
+ assert binomial(n, n + p).func == binomial
451
+ assert binomial(kp, kp + p).func == binomial
452
+
453
+ assert expand_func(binomial(n, n - 3)) == n*(n - 2)*(n - 1)/6
454
+
455
+ assert binomial(n, k).is_integer
456
+ assert binomial(nt, k).is_integer is None
457
+ assert binomial(x, nt).is_integer is False
458
+
459
+ assert binomial(gamma(25), 6) == 79232165267303928292058750056084441948572511312165380965440075720159859792344339983120618959044048198214221915637090855535036339620413440000
460
+ assert binomial(1324, 47) == 906266255662694632984994480774946083064699457235920708992926525848438478406790323869952
461
+ assert binomial(1735, 43) == 190910140420204130794758005450919715396159959034348676124678207874195064798202216379800
462
+ assert binomial(2512, 53) == 213894469313832631145798303740098720367984955243020898718979538096223399813295457822575338958939834177325304000
463
+ assert binomial(3383, 52) == 27922807788818096863529701501764372757272890613101645521813434902890007725667814813832027795881839396839287659777235
464
+ assert binomial(4321, 51) == 124595639629264868916081001263541480185227731958274383287107643816863897851139048158022599533438936036467601690983780576
465
+
466
+ assert binomial(a, b).is_nonnegative is True
467
+ assert binomial(-1, 2, evaluate=False).is_nonnegative is True
468
+ assert binomial(10, 5, evaluate=False).is_nonnegative is True
469
+ assert binomial(10, -3, evaluate=False).is_nonnegative is True
470
+ assert binomial(-10, -3, evaluate=False).is_nonnegative is True
471
+ assert binomial(-10, 2, evaluate=False).is_nonnegative is True
472
+ assert binomial(-10, 1, evaluate=False).is_nonnegative is False
473
+ assert binomial(-10, 7, evaluate=False).is_nonnegative is False
474
+
475
+ # issue #14625
476
+ for _ in (pi, -pi, nt, v, a):
477
+ assert binomial(_, _) == 1
478
+ assert binomial(_, _ - 1) == _
479
+ assert isinstance(binomial(u, u), binomial)
480
+ assert isinstance(binomial(u, u - 1), binomial)
481
+ assert isinstance(binomial(x, x), binomial)
482
+ assert isinstance(binomial(x, x - 1), binomial)
483
+
484
+ #issue #18802
485
+ assert expand_func(binomial(x + 1, x)) == x + 1
486
+ assert expand_func(binomial(x, x - 1)) == x
487
+ assert expand_func(binomial(x + 1, x - 1)) == x*(x + 1)/2
488
+ assert expand_func(binomial(x**2 + 1, x**2)) == x**2 + 1
489
+
490
+ # issue #13980 and #13981
491
+ assert binomial(-7, -5) == 0
492
+ assert binomial(-23, -12) == 0
493
+ assert binomial(Rational(13, 2), -10) == 0
494
+ assert binomial(-49, -51) == 0
495
+
496
+ assert binomial(19, Rational(-7, 2)) == S(-68719476736)/(911337863661225*pi)
497
+ assert binomial(0, Rational(3, 2)) == S(-2)/(3*pi)
498
+ assert binomial(-3, Rational(-7, 2)) is zoo
499
+ assert binomial(kn, kt) is zoo
500
+
501
+ assert binomial(nt, kt).func == binomial
502
+ assert binomial(nt, Rational(15, 6)) == 8*gamma(nt + 1)/(15*sqrt(pi)*gamma(nt - Rational(3, 2)))
503
+ assert binomial(Rational(20, 3), Rational(-10, 8)) == gamma(Rational(23, 3))/(gamma(Rational(-1, 4))*gamma(Rational(107, 12)))
504
+ assert binomial(Rational(19, 2), Rational(-7, 2)) == Rational(-1615, 8388608)
505
+ assert binomial(Rational(-13, 5), Rational(-7, 8)) == gamma(Rational(-8, 5))/(gamma(Rational(-29, 40))*gamma(Rational(1, 8)))
506
+ assert binomial(Rational(-19, 8), Rational(-13, 5)) == gamma(Rational(-11, 8))/(gamma(Rational(-8, 5))*gamma(Rational(49, 40)))
507
+
508
+ # binomial for complexes
509
+ assert binomial(I, Rational(-89, 8)) == gamma(1 + I)/(gamma(Rational(-81, 8))*gamma(Rational(97, 8) + I))
510
+ assert binomial(I, 2*I) == gamma(1 + I)/(gamma(1 - I)*gamma(1 + 2*I))
511
+ assert binomial(-7, I) is zoo
512
+ assert binomial(Rational(-7, 6), I) == gamma(Rational(-1, 6))/(gamma(Rational(-1, 6) - I)*gamma(1 + I))
513
+ assert binomial((1+2*I), (1+3*I)) == gamma(2 + 2*I)/(gamma(1 - I)*gamma(2 + 3*I))
514
+ assert binomial(I, 5) == Rational(1, 3) - I/S(12)
515
+ assert binomial((2*I + 3), 7) == -13*I/S(63)
516
+ assert isinstance(binomial(I, n), binomial)
517
+ assert expand_func(binomial(3, 2, evaluate=False)) == 3
518
+ assert expand_func(binomial(n, 0, evaluate=False)) == 1
519
+ assert expand_func(binomial(n, -2, evaluate=False)) == 0
520
+ assert expand_func(binomial(n, k)) == binomial(n, k)
521
+
522
+
523
+ def test_binomial_Mod():
524
+ p, q = 10**5 + 3, 10**9 + 33 # prime modulo
525
+ r = 10**7 + 5 # composite modulo
526
+
527
+ # A few tests to get coverage
528
+ # Lucas Theorem
529
+ assert Mod(binomial(156675, 4433, evaluate=False), p) == Mod(binomial(156675, 4433), p)
530
+
531
+ # factorial Mod
532
+ assert Mod(binomial(1234, 432, evaluate=False), q) == Mod(binomial(1234, 432), q)
533
+
534
+ # binomial factorize
535
+ assert Mod(binomial(253, 113, evaluate=False), r) == Mod(binomial(253, 113), r)
536
+
537
+
538
+ @slow
539
+ def test_binomial_Mod_slow():
540
+ p, q = 10**5 + 3, 10**9 + 33 # prime modulo
541
+ r, s = 10**7 + 5, 33333333 # composite modulo
542
+
543
+ n, k, m = symbols('n k m')
544
+ assert (binomial(n, k) % q).subs({n: s, k: p}) == Mod(binomial(s, p), q)
545
+ assert (binomial(n, k) % m).subs({n: 8, k: 5, m: 13}) == 4
546
+ assert (binomial(9, k) % 7).subs(k, 2) == 1
547
+
548
+ # Lucas Theorem
549
+ assert Mod(binomial(123456, 43253, evaluate=False), p) == Mod(binomial(123456, 43253), p)
550
+ assert Mod(binomial(-178911, 237, evaluate=False), p) == Mod(-binomial(178911 + 237 - 1, 237), p)
551
+ assert Mod(binomial(-178911, 238, evaluate=False), p) == Mod(binomial(178911 + 238 - 1, 238), p)
552
+
553
+ # factorial Mod
554
+ assert Mod(binomial(9734, 451, evaluate=False), q) == Mod(binomial(9734, 451), q)
555
+ assert Mod(binomial(-10733, 4459, evaluate=False), q) == Mod(binomial(-10733, 4459), q)
556
+ assert Mod(binomial(-15733, 4458, evaluate=False), q) == Mod(binomial(-15733, 4458), q)
557
+ assert Mod(binomial(23, -38, evaluate=False), q) is S.Zero
558
+ assert Mod(binomial(23, 38, evaluate=False), q) is S.Zero
559
+
560
+ # binomial factorize
561
+ assert Mod(binomial(753, 119, evaluate=False), r) == Mod(binomial(753, 119), r)
562
+ assert Mod(binomial(3781, 948, evaluate=False), s) == Mod(binomial(3781, 948), s)
563
+ assert Mod(binomial(25773, 1793, evaluate=False), s) == Mod(binomial(25773, 1793), s)
564
+ assert Mod(binomial(-753, 118, evaluate=False), r) == Mod(binomial(-753, 118), r)
565
+ assert Mod(binomial(-25773, 1793, evaluate=False), s) == Mod(binomial(-25773, 1793), s)
566
+
567
+
568
+ def test_binomial_diff():
569
+ n = Symbol('n', integer=True)
570
+ k = Symbol('k', integer=True)
571
+
572
+ assert binomial(n, k).diff(n) == \
573
+ (-polygamma(0, 1 + n - k) + polygamma(0, 1 + n))*binomial(n, k)
574
+ assert binomial(n**2, k**3).diff(n) == \
575
+ 2*n*(-polygamma(
576
+ 0, 1 + n**2 - k**3) + polygamma(0, 1 + n**2))*binomial(n**2, k**3)
577
+
578
+ assert binomial(n, k).diff(k) == \
579
+ (-polygamma(0, 1 + k) + polygamma(0, 1 + n - k))*binomial(n, k)
580
+ assert binomial(n**2, k**3).diff(k) == \
581
+ 3*k**2*(-polygamma(
582
+ 0, 1 + k**3) + polygamma(0, 1 + n**2 - k**3))*binomial(n**2, k**3)
583
+ raises(ArgumentIndexError, lambda: binomial(n, k).fdiff(3))
584
+
585
+
586
+ def test_binomial_rewrite():
587
+ n = Symbol('n', integer=True)
588
+ k = Symbol('k', integer=True)
589
+ x = Symbol('x')
590
+
591
+ assert binomial(n, k).rewrite(
592
+ factorial) == factorial(n)/(factorial(k)*factorial(n - k))
593
+ assert binomial(
594
+ n, k).rewrite(gamma) == gamma(n + 1)/(gamma(k + 1)*gamma(n - k + 1))
595
+ assert binomial(n, k).rewrite(ff) == ff(n, k) / factorial(k)
596
+ assert binomial(n, x).rewrite(ff) == binomial(n, x)
597
+
598
+
599
+ @XFAIL
600
+ def test_factorial_simplify_fail():
601
+ # simplify(factorial(x + 1).diff(x) - ((x + 1)*factorial(x)).diff(x))) == 0
602
+ from sympy.abc import x
603
+ assert simplify(x*polygamma(0, x + 1) - x*polygamma(0, x + 2) +
604
+ polygamma(0, x + 1) - polygamma(0, x + 2) + 1) == 0
605
+
606
+
607
+ def test_subfactorial():
608
+ assert all(subfactorial(i) == ans for i, ans in enumerate(
609
+ [1, 0, 1, 2, 9, 44, 265, 1854, 14833, 133496]))
610
+ assert subfactorial(oo) is oo
611
+ assert subfactorial(nan) is nan
612
+ assert subfactorial(23) == 9510425471055777937262
613
+ assert unchanged(subfactorial, 2.2)
614
+
615
+ x = Symbol('x')
616
+ assert subfactorial(x).rewrite(uppergamma) == uppergamma(x + 1, -1)/S.Exp1
617
+
618
+ tt = Symbol('tt', integer=True, nonnegative=True)
619
+ tf = Symbol('tf', integer=True, nonnegative=False)
620
+ tn = Symbol('tf', integer=True)
621
+ ft = Symbol('ft', integer=False, nonnegative=True)
622
+ ff = Symbol('ff', integer=False, nonnegative=False)
623
+ fn = Symbol('ff', integer=False)
624
+ nt = Symbol('nt', nonnegative=True)
625
+ nf = Symbol('nf', nonnegative=False)
626
+ nn = Symbol('nf')
627
+ te = Symbol('te', even=True, nonnegative=True)
628
+ to = Symbol('to', odd=True, nonnegative=True)
629
+ assert subfactorial(tt).is_integer
630
+ assert subfactorial(tf).is_integer is None
631
+ assert subfactorial(tn).is_integer is None
632
+ assert subfactorial(ft).is_integer is None
633
+ assert subfactorial(ff).is_integer is None
634
+ assert subfactorial(fn).is_integer is None
635
+ assert subfactorial(nt).is_integer is None
636
+ assert subfactorial(nf).is_integer is None
637
+ assert subfactorial(nn).is_integer is None
638
+ assert subfactorial(tt).is_nonnegative
639
+ assert subfactorial(tf).is_nonnegative is None
640
+ assert subfactorial(tn).is_nonnegative is None
641
+ assert subfactorial(ft).is_nonnegative is None
642
+ assert subfactorial(ff).is_nonnegative is None
643
+ assert subfactorial(fn).is_nonnegative is None
644
+ assert subfactorial(nt).is_nonnegative is None
645
+ assert subfactorial(nf).is_nonnegative is None
646
+ assert subfactorial(nn).is_nonnegative is None
647
+ assert subfactorial(tt).is_even is None
648
+ assert subfactorial(tt).is_odd is None
649
+ assert subfactorial(te).is_odd is True
650
+ assert subfactorial(to).is_even is True
venv/lib/python3.10/site-packages/sympy/functions/combinatorial/tests/test_comb_numbers.py ADDED
@@ -0,0 +1,852 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ import string
2
+
3
+ from sympy.concrete.products import Product
4
+ from sympy.concrete.summations import Sum
5
+ from sympy.core.function import (diff, expand_func)
6
+ from sympy.core import (EulerGamma, TribonacciConstant)
7
+ from sympy.core.numbers import (Float, I, Rational, oo, pi)
8
+ from sympy.core.singleton import S
9
+ from sympy.core.symbol import (Dummy, Symbol, symbols)
10
+ from sympy.functions.combinatorial.numbers import carmichael
11
+ from sympy.functions.elementary.complexes import (im, re)
12
+ from sympy.functions.elementary.integers import floor
13
+ from sympy.polys.polytools import cancel
14
+ from sympy.series.limits import limit, Limit
15
+ from sympy.series.order import O
16
+ from sympy.functions import (
17
+ bernoulli, harmonic, bell, fibonacci, tribonacci, lucas, euler, catalan,
18
+ genocchi, andre, partition, motzkin, binomial, gamma, sqrt, cbrt, hyper, log, digamma,
19
+ trigamma, polygamma, factorial, sin, cos, cot, polylog, zeta, dirichlet_eta)
20
+ from sympy.functions.combinatorial.numbers import _nT
21
+
22
+ from sympy.core.expr import unchanged
23
+ from sympy.core.numbers import GoldenRatio, Integer
24
+
25
+ from sympy.testing.pytest import raises, nocache_fail, warns_deprecated_sympy
26
+ from sympy.abc import x
27
+
28
+
29
+ def test_carmichael():
30
+ assert carmichael.find_carmichael_numbers_in_range(0, 561) == []
31
+ assert carmichael.find_carmichael_numbers_in_range(561, 562) == [561]
32
+ assert carmichael.find_carmichael_numbers_in_range(561, 1105) == carmichael.find_carmichael_numbers_in_range(561,
33
+ 562)
34
+ assert carmichael.find_first_n_carmichaels(5) == [561, 1105, 1729, 2465, 2821]
35
+ raises(ValueError, lambda: carmichael.is_carmichael(-2))
36
+ raises(ValueError, lambda: carmichael.find_carmichael_numbers_in_range(-2, 2))
37
+ raises(ValueError, lambda: carmichael.find_carmichael_numbers_in_range(22, 2))
38
+ with warns_deprecated_sympy():
39
+ assert carmichael.is_prime(2821) == False
40
+
41
+
42
+ def test_bernoulli():
43
+ assert bernoulli(0) == 1
44
+ assert bernoulli(1) == Rational(1, 2)
45
+ assert bernoulli(2) == Rational(1, 6)
46
+ assert bernoulli(3) == 0
47
+ assert bernoulli(4) == Rational(-1, 30)
48
+ assert bernoulli(5) == 0
49
+ assert bernoulli(6) == Rational(1, 42)
50
+ assert bernoulli(7) == 0
51
+ assert bernoulli(8) == Rational(-1, 30)
52
+ assert bernoulli(10) == Rational(5, 66)
53
+ assert bernoulli(1000001) == 0
54
+
55
+ assert bernoulli(0, x) == 1
56
+ assert bernoulli(1, x) == x - S.Half
57
+ assert bernoulli(2, x) == x**2 - x + Rational(1, 6)
58
+ assert bernoulli(3, x) == x**3 - (3*x**2)/2 + x/2
59
+
60
+ # Should be fast; computed with mpmath
61
+ b = bernoulli(1000)
62
+ assert b.p % 10**10 == 7950421099
63
+ assert b.q == 342999030
64
+
65
+ b = bernoulli(10**6, evaluate=False).evalf()
66
+ assert str(b) == '-2.23799235765713e+4767529'
67
+
68
+ # Issue #8527
69
+ l = Symbol('l', integer=True)
70
+ m = Symbol('m', integer=True, nonnegative=True)
71
+ n = Symbol('n', integer=True, positive=True)
72
+ assert isinstance(bernoulli(2 * l + 1), bernoulli)
73
+ assert isinstance(bernoulli(2 * m + 1), bernoulli)
74
+ assert bernoulli(2 * n + 1) == 0
75
+
76
+ assert bernoulli(x, 1) == bernoulli(x)
77
+
78
+ assert str(bernoulli(0.0, 2.3).evalf(n=10)) == '1.000000000'
79
+ assert str(bernoulli(1.0).evalf(n=10)) == '0.5000000000'
80
+ assert str(bernoulli(1.2).evalf(n=10)) == '0.4195995367'
81
+ assert str(bernoulli(1.2, 0.8).evalf(n=10)) == '0.2144830348'
82
+ assert str(bernoulli(1.2, -0.8).evalf(n=10)) == '-1.158865646 - 0.6745558744*I'
83
+ assert str(bernoulli(3.0, 1j).evalf(n=10)) == '1.5 - 0.5*I'
84
+ assert str(bernoulli(I).evalf(n=10)) == '0.9268485643 - 0.5821580598*I'
85
+ assert str(bernoulli(I, I).evalf(n=10)) == '0.1267792071 + 0.01947413152*I'
86
+ assert bernoulli(x).evalf() == bernoulli(x)
87
+
88
+
89
+ def test_bernoulli_rewrite():
90
+ from sympy.functions.elementary.piecewise import Piecewise
91
+ n = Symbol('n', integer=True, nonnegative=True)
92
+
93
+ assert bernoulli(-1).rewrite(zeta) == pi**2/6
94
+ assert bernoulli(-2).rewrite(zeta) == 2*zeta(3)
95
+ assert not bernoulli(n, -3).rewrite(zeta).has(harmonic)
96
+ assert bernoulli(-4, x).rewrite(zeta) == 4*zeta(5, x)
97
+ assert isinstance(bernoulli(n, x).rewrite(zeta), Piecewise)
98
+ assert bernoulli(n+1, x).rewrite(zeta) == -(n+1) * zeta(-n, x)
99
+
100
+
101
+ def test_fibonacci():
102
+ assert [fibonacci(n) for n in range(-3, 5)] == [2, -1, 1, 0, 1, 1, 2, 3]
103
+ assert fibonacci(100) == 354224848179261915075
104
+ assert [lucas(n) for n in range(-3, 5)] == [-4, 3, -1, 2, 1, 3, 4, 7]
105
+ assert lucas(100) == 792070839848372253127
106
+
107
+ assert fibonacci(1, x) == 1
108
+ assert fibonacci(2, x) == x
109
+ assert fibonacci(3, x) == x**2 + 1
110
+ assert fibonacci(4, x) == x**3 + 2*x
111
+
112
+ # issue #8800
113
+ n = Dummy('n')
114
+ assert fibonacci(n).limit(n, S.Infinity) is S.Infinity
115
+ assert lucas(n).limit(n, S.Infinity) is S.Infinity
116
+
117
+ assert fibonacci(n).rewrite(sqrt) == \
118
+ 2**(-n)*sqrt(5)*((1 + sqrt(5))**n - (-sqrt(5) + 1)**n) / 5
119
+ assert fibonacci(n).rewrite(sqrt).subs(n, 10).expand() == fibonacci(10)
120
+ assert fibonacci(n).rewrite(GoldenRatio).subs(n,10).evalf() == \
121
+ Float(fibonacci(10))
122
+ assert lucas(n).rewrite(sqrt) == \
123
+ (fibonacci(n-1).rewrite(sqrt) + fibonacci(n+1).rewrite(sqrt)).simplify()
124
+ assert lucas(n).rewrite(sqrt).subs(n, 10).expand() == lucas(10)
125
+ raises(ValueError, lambda: fibonacci(-3, x))
126
+
127
+
128
+ def test_tribonacci():
129
+ assert [tribonacci(n) for n in range(8)] == [0, 1, 1, 2, 4, 7, 13, 24]
130
+ assert tribonacci(100) == 98079530178586034536500564
131
+
132
+ assert tribonacci(0, x) == 0
133
+ assert tribonacci(1, x) == 1
134
+ assert tribonacci(2, x) == x**2
135
+ assert tribonacci(3, x) == x**4 + x
136
+ assert tribonacci(4, x) == x**6 + 2*x**3 + 1
137
+ assert tribonacci(5, x) == x**8 + 3*x**5 + 3*x**2
138
+
139
+ n = Dummy('n')
140
+ assert tribonacci(n).limit(n, S.Infinity) is S.Infinity
141
+
142
+ w = (-1 + S.ImaginaryUnit * sqrt(3)) / 2
143
+ a = (1 + cbrt(19 + 3*sqrt(33)) + cbrt(19 - 3*sqrt(33))) / 3
144
+ b = (1 + w*cbrt(19 + 3*sqrt(33)) + w**2*cbrt(19 - 3*sqrt(33))) / 3
145
+ c = (1 + w**2*cbrt(19 + 3*sqrt(33)) + w*cbrt(19 - 3*sqrt(33))) / 3
146
+ assert tribonacci(n).rewrite(sqrt) == \
147
+ (a**(n + 1)/((a - b)*(a - c))
148
+ + b**(n + 1)/((b - a)*(b - c))
149
+ + c**(n + 1)/((c - a)*(c - b)))
150
+ assert tribonacci(n).rewrite(sqrt).subs(n, 4).simplify() == tribonacci(4)
151
+ assert tribonacci(n).rewrite(GoldenRatio).subs(n,10).evalf() == \
152
+ Float(tribonacci(10))
153
+ assert tribonacci(n).rewrite(TribonacciConstant) == floor(
154
+ 3*TribonacciConstant**n*(102*sqrt(33) + 586)**Rational(1, 3)/
155
+ (-2*(102*sqrt(33) + 586)**Rational(1, 3) + 4 + (102*sqrt(33)
156
+ + 586)**Rational(2, 3)) + S.Half)
157
+ raises(ValueError, lambda: tribonacci(-1, x))
158
+
159
+
160
+ @nocache_fail
161
+ def test_bell():
162
+ assert [bell(n) for n in range(8)] == [1, 1, 2, 5, 15, 52, 203, 877]
163
+
164
+ assert bell(0, x) == 1
165
+ assert bell(1, x) == x
166
+ assert bell(2, x) == x**2 + x
167
+ assert bell(5, x) == x**5 + 10*x**4 + 25*x**3 + 15*x**2 + x
168
+ assert bell(oo) is S.Infinity
169
+ raises(ValueError, lambda: bell(oo, x))
170
+
171
+ raises(ValueError, lambda: bell(-1))
172
+ raises(ValueError, lambda: bell(S.Half))
173
+
174
+ X = symbols('x:6')
175
+ # X = (x0, x1, .. x5)
176
+ # at the same time: X[1] = x1, X[2] = x2 for standard readablity.
177
+ # but we must supply zero-based indexed object X[1:] = (x1, .. x5)
178
+
179
+ assert bell(6, 2, X[1:]) == 6*X[5]*X[1] + 15*X[4]*X[2] + 10*X[3]**2
180
+ assert bell(
181
+ 6, 3, X[1:]) == 15*X[4]*X[1]**2 + 60*X[3]*X[2]*X[1] + 15*X[2]**3
182
+
183
+ X = (1, 10, 100, 1000, 10000)
184
+ assert bell(6, 2, X) == (6 + 15 + 10)*10000
185
+
186
+ X = (1, 2, 3, 3, 5)
187
+ assert bell(6, 2, X) == 6*5 + 15*3*2 + 10*3**2
188
+
189
+ X = (1, 2, 3, 5)
190
+ assert bell(6, 3, X) == 15*5 + 60*3*2 + 15*2**3
191
+
192
+ # Dobinski's formula
193
+ n = Symbol('n', integer=True, nonnegative=True)
194
+ # For large numbers, this is too slow
195
+ # For nonintegers, there are significant precision errors
196
+ for i in [0, 2, 3, 7, 13, 42, 55]:
197
+ # Running without the cache this is either very slow or goes into an
198
+ # infinite loop.
199
+ assert bell(i).evalf() == bell(n).rewrite(Sum).evalf(subs={n: i})
200
+
201
+ m = Symbol("m")
202
+ assert bell(m).rewrite(Sum) == bell(m)
203
+ assert bell(n, m).rewrite(Sum) == bell(n, m)
204
+ # issue 9184
205
+ n = Dummy('n')
206
+ assert bell(n).limit(n, S.Infinity) is S.Infinity
207
+
208
+
209
+ def test_harmonic():
210
+ n = Symbol("n")
211
+ m = Symbol("m")
212
+
213
+ assert harmonic(n, 0) == n
214
+ assert harmonic(n).evalf() == harmonic(n)
215
+ assert harmonic(n, 1) == harmonic(n)
216
+ assert harmonic(1, n) == 1
217
+
218
+ assert harmonic(0, 1) == 0
219
+ assert harmonic(1, 1) == 1
220
+ assert harmonic(2, 1) == Rational(3, 2)
221
+ assert harmonic(3, 1) == Rational(11, 6)
222
+ assert harmonic(4, 1) == Rational(25, 12)
223
+ assert harmonic(0, 2) == 0
224
+ assert harmonic(1, 2) == 1
225
+ assert harmonic(2, 2) == Rational(5, 4)
226
+ assert harmonic(3, 2) == Rational(49, 36)
227
+ assert harmonic(4, 2) == Rational(205, 144)
228
+ assert harmonic(0, 3) == 0
229
+ assert harmonic(1, 3) == 1
230
+ assert harmonic(2, 3) == Rational(9, 8)
231
+ assert harmonic(3, 3) == Rational(251, 216)
232
+ assert harmonic(4, 3) == Rational(2035, 1728)
233
+
234
+ assert harmonic(oo, -1) is S.NaN
235
+ assert harmonic(oo, 0) is oo
236
+ assert harmonic(oo, S.Half) is oo
237
+ assert harmonic(oo, 1) is oo
238
+ assert harmonic(oo, 2) == (pi**2)/6
239
+ assert harmonic(oo, 3) == zeta(3)
240
+ assert harmonic(oo, Dummy(negative=True)) is S.NaN
241
+ ip = Dummy(integer=True, positive=True)
242
+ if (1/ip <= 1) is True: #---------------------------------+
243
+ assert None, 'delete this if-block and the next line' #|
244
+ ip = Dummy(even=True, positive=True) #--------------------+
245
+ assert harmonic(oo, 1/ip) is oo
246
+ assert harmonic(oo, 1 + ip) is zeta(1 + ip)
247
+
248
+ assert harmonic(0, m) == 0
249
+ assert harmonic(-1, -1) == 0
250
+ assert harmonic(-1, 0) == -1
251
+ assert harmonic(-1, 1) is S.ComplexInfinity
252
+ assert harmonic(-1, 2) is S.NaN
253
+ assert harmonic(-3, -2) == -5
254
+ assert harmonic(-3, -3) == 9
255
+
256
+
257
+ def test_harmonic_rational():
258
+ ne = S(6)
259
+ no = S(5)
260
+ pe = S(8)
261
+ po = S(9)
262
+ qe = S(10)
263
+ qo = S(13)
264
+
265
+ Heee = harmonic(ne + pe/qe)
266
+ Aeee = (-log(10) + 2*(Rational(-1, 4) + sqrt(5)/4)*log(sqrt(-sqrt(5)/8 + Rational(5, 8)))
267
+ + 2*(-sqrt(5)/4 - Rational(1, 4))*log(sqrt(sqrt(5)/8 + Rational(5, 8)))
268
+ + pi*sqrt(2*sqrt(5)/5 + 1)/2 + Rational(13944145, 4720968))
269
+
270
+ Heeo = harmonic(ne + pe/qo)
271
+ Aeeo = (-log(26) + 2*log(sin(pi*Rational(3, 13)))*cos(pi*Rational(4, 13)) + 2*log(sin(pi*Rational(2, 13)))*cos(pi*Rational(32, 13))
272
+ + 2*log(sin(pi*Rational(5, 13)))*cos(pi*Rational(80, 13)) - 2*log(sin(pi*Rational(6, 13)))*cos(pi*Rational(5, 13))
273
+ - 2*log(sin(pi*Rational(4, 13)))*cos(pi/13) + pi*cot(pi*Rational(5, 13))/2 - 2*log(sin(pi/13))*cos(pi*Rational(3, 13))
274
+ + Rational(2422020029, 702257080))
275
+
276
+ Heoe = harmonic(ne + po/qe)
277
+ Aeoe = (-log(20) + 2*(Rational(1, 4) + sqrt(5)/4)*log(Rational(-1, 4) + sqrt(5)/4)
278
+ + 2*(Rational(-1, 4) + sqrt(5)/4)*log(sqrt(-sqrt(5)/8 + Rational(5, 8)))
279
+ + 2*(-sqrt(5)/4 - Rational(1, 4))*log(sqrt(sqrt(5)/8 + Rational(5, 8)))
280
+ + 2*(-sqrt(5)/4 + Rational(1, 4))*log(Rational(1, 4) + sqrt(5)/4)
281
+ + Rational(11818877030, 4286604231) + pi*sqrt(2*sqrt(5) + 5)/2)
282
+
283
+ Heoo = harmonic(ne + po/qo)
284
+ Aeoo = (-log(26) + 2*log(sin(pi*Rational(3, 13)))*cos(pi*Rational(54, 13)) + 2*log(sin(pi*Rational(4, 13)))*cos(pi*Rational(6, 13))
285
+ + 2*log(sin(pi*Rational(6, 13)))*cos(pi*Rational(108, 13)) - 2*log(sin(pi*Rational(5, 13)))*cos(pi/13)
286
+ - 2*log(sin(pi/13))*cos(pi*Rational(5, 13)) + pi*cot(pi*Rational(4, 13))/2
287
+ - 2*log(sin(pi*Rational(2, 13)))*cos(pi*Rational(3, 13)) + Rational(11669332571, 3628714320))
288
+
289
+ Hoee = harmonic(no + pe/qe)
290
+ Aoee = (-log(10) + 2*(Rational(-1, 4) + sqrt(5)/4)*log(sqrt(-sqrt(5)/8 + Rational(5, 8)))
291
+ + 2*(-sqrt(5)/4 - Rational(1, 4))*log(sqrt(sqrt(5)/8 + Rational(5, 8)))
292
+ + pi*sqrt(2*sqrt(5)/5 + 1)/2 + Rational(779405, 277704))
293
+
294
+ Hoeo = harmonic(no + pe/qo)
295
+ Aoeo = (-log(26) + 2*log(sin(pi*Rational(3, 13)))*cos(pi*Rational(4, 13)) + 2*log(sin(pi*Rational(2, 13)))*cos(pi*Rational(32, 13))
296
+ + 2*log(sin(pi*Rational(5, 13)))*cos(pi*Rational(80, 13)) - 2*log(sin(pi*Rational(6, 13)))*cos(pi*Rational(5, 13))
297
+ - 2*log(sin(pi*Rational(4, 13)))*cos(pi/13) + pi*cot(pi*Rational(5, 13))/2
298
+ - 2*log(sin(pi/13))*cos(pi*Rational(3, 13)) + Rational(53857323, 16331560))
299
+
300
+ Hooe = harmonic(no + po/qe)
301
+ Aooe = (-log(20) + 2*(Rational(1, 4) + sqrt(5)/4)*log(Rational(-1, 4) + sqrt(5)/4)
302
+ + 2*(Rational(-1, 4) + sqrt(5)/4)*log(sqrt(-sqrt(5)/8 + Rational(5, 8)))
303
+ + 2*(-sqrt(5)/4 - Rational(1, 4))*log(sqrt(sqrt(5)/8 + Rational(5, 8)))
304
+ + 2*(-sqrt(5)/4 + Rational(1, 4))*log(Rational(1, 4) + sqrt(5)/4)
305
+ + Rational(486853480, 186374097) + pi*sqrt(2*sqrt(5) + 5)/2)
306
+
307
+ Hooo = harmonic(no + po/qo)
308
+ Aooo = (-log(26) + 2*log(sin(pi*Rational(3, 13)))*cos(pi*Rational(54, 13)) + 2*log(sin(pi*Rational(4, 13)))*cos(pi*Rational(6, 13))
309
+ + 2*log(sin(pi*Rational(6, 13)))*cos(pi*Rational(108, 13)) - 2*log(sin(pi*Rational(5, 13)))*cos(pi/13)
310
+ - 2*log(sin(pi/13))*cos(pi*Rational(5, 13)) + pi*cot(pi*Rational(4, 13))/2
311
+ - 2*log(sin(pi*Rational(2, 13)))*cos(3*pi/13) + Rational(383693479, 125128080))
312
+
313
+ H = [Heee, Heeo, Heoe, Heoo, Hoee, Hoeo, Hooe, Hooo]
314
+ A = [Aeee, Aeeo, Aeoe, Aeoo, Aoee, Aoeo, Aooe, Aooo]
315
+ for h, a in zip(H, A):
316
+ e = expand_func(h).doit()
317
+ assert cancel(e/a) == 1
318
+ assert abs(h.n() - a.n()) < 1e-12
319
+
320
+
321
+ def test_harmonic_evalf():
322
+ assert str(harmonic(1.5).evalf(n=10)) == '1.280372306'
323
+ assert str(harmonic(1.5, 2).evalf(n=10)) == '1.154576311' # issue 7443
324
+ assert str(harmonic(4.0, -3).evalf(n=10)) == '100.0000000'
325
+ assert str(harmonic(7.0, 1.0).evalf(n=10)) == '2.592857143'
326
+ assert str(harmonic(1, pi).evalf(n=10)) == '1.000000000'
327
+ assert str(harmonic(2, pi).evalf(n=10)) == '1.113314732'
328
+ assert str(harmonic(1000.0, pi).evalf(n=10)) == '1.176241563'
329
+ assert str(harmonic(I).evalf(n=10)) == '0.6718659855 + 1.076674047*I'
330
+ assert str(harmonic(I, I).evalf(n=10)) == '-0.3970915266 + 1.9629689*I'
331
+
332
+ assert harmonic(-1.0, 1).evalf() is S.NaN
333
+ assert harmonic(-2.0, 2.0).evalf() is S.NaN
334
+
335
+ def test_harmonic_rewrite():
336
+ from sympy.functions.elementary.piecewise import Piecewise
337
+ n = Symbol("n")
338
+ m = Symbol("m", integer=True, positive=True)
339
+ x1 = Symbol("x1", positive=True)
340
+ x2 = Symbol("x2", negative=True)
341
+
342
+ assert harmonic(n).rewrite(digamma) == polygamma(0, n + 1) + EulerGamma
343
+ assert harmonic(n).rewrite(trigamma) == polygamma(0, n + 1) + EulerGamma
344
+ assert harmonic(n).rewrite(polygamma) == polygamma(0, n + 1) + EulerGamma
345
+
346
+ assert harmonic(n,3).rewrite(polygamma) == polygamma(2, n + 1)/2 - polygamma(2, 1)/2
347
+ assert isinstance(harmonic(n,m).rewrite(polygamma), Piecewise)
348
+
349
+ assert expand_func(harmonic(n+4)) == harmonic(n) + 1/(n + 4) + 1/(n + 3) + 1/(n + 2) + 1/(n + 1)
350
+ assert expand_func(harmonic(n-4)) == harmonic(n) - 1/(n - 1) - 1/(n - 2) - 1/(n - 3) - 1/n
351
+
352
+ assert harmonic(n, m).rewrite("tractable") == harmonic(n, m).rewrite(polygamma)
353
+ assert harmonic(n, x1).rewrite("tractable") == harmonic(n, x1)
354
+ assert harmonic(n, x1 + 1).rewrite("tractable") == zeta(x1 + 1) - zeta(x1 + 1, n + 1)
355
+ assert harmonic(n, x2).rewrite("tractable") == zeta(x2) - zeta(x2, n + 1)
356
+
357
+ _k = Dummy("k")
358
+ assert harmonic(n).rewrite(Sum).dummy_eq(Sum(1/_k, (_k, 1, n)))
359
+ assert harmonic(n, m).rewrite(Sum).dummy_eq(Sum(_k**(-m), (_k, 1, n)))
360
+
361
+
362
+ def test_harmonic_calculus():
363
+ y = Symbol("y", positive=True)
364
+ z = Symbol("z", negative=True)
365
+ assert harmonic(x, 1).limit(x, 0) == 0
366
+ assert harmonic(x, y).limit(x, 0) == 0
367
+ assert harmonic(x, 1).series(x, y, 2) == \
368
+ harmonic(y) + (x - y)*zeta(2, y + 1) + O((x - y)**2, (x, y))
369
+ assert limit(harmonic(x, y), x, oo) == harmonic(oo, y)
370
+ assert limit(harmonic(x, y + 1), x, oo) == zeta(y + 1)
371
+ assert limit(harmonic(x, y - 1), x, oo) == harmonic(oo, y - 1)
372
+ assert limit(harmonic(x, z), x, oo) == Limit(harmonic(x, z), x, oo, dir='-')
373
+ assert limit(harmonic(x, z + 1), x, oo) == oo
374
+ assert limit(harmonic(x, z + 2), x, oo) == harmonic(oo, z + 2)
375
+ assert limit(harmonic(x, z - 1), x, oo) == Limit(harmonic(x, z - 1), x, oo, dir='-')
376
+
377
+
378
+ def test_euler():
379
+ assert euler(0) == 1
380
+ assert euler(1) == 0
381
+ assert euler(2) == -1
382
+ assert euler(3) == 0
383
+ assert euler(4) == 5
384
+ assert euler(6) == -61
385
+ assert euler(8) == 1385
386
+
387
+ assert euler(20, evaluate=False) != 370371188237525
388
+
389
+ n = Symbol('n', integer=True)
390
+ assert euler(n) != -1
391
+ assert euler(n).subs(n, 2) == -1
392
+
393
+ assert euler(-1) == S.Pi / 2
394
+ assert euler(-1, 1) == 2*log(2)
395
+ assert euler(-2).evalf() == (2*S.Catalan).evalf()
396
+ assert euler(-3).evalf() == (S.Pi**3 / 16).evalf()
397
+ assert str(euler(2.3).evalf(n=10)) == '-1.052850274'
398
+ assert str(euler(1.2, 3.4).evalf(n=10)) == '3.575613489'
399
+ assert str(euler(I).evalf(n=10)) == '1.248446443 - 0.7675445124*I'
400
+ assert str(euler(I, I).evalf(n=10)) == '0.04812930469 + 0.01052411008*I'
401
+
402
+ assert euler(20).evalf() == 370371188237525.0
403
+ assert euler(20, evaluate=False).evalf() == 370371188237525.0
404
+
405
+ assert euler(n).rewrite(Sum) == euler(n)
406
+ n = Symbol('n', integer=True, nonnegative=True)
407
+ assert euler(2*n + 1).rewrite(Sum) == 0
408
+ _j = Dummy('j')
409
+ _k = Dummy('k')
410
+ assert euler(2*n).rewrite(Sum).dummy_eq(
411
+ I*Sum((-1)**_j*2**(-_k)*I**(-_k)*(-2*_j + _k)**(2*n + 1)*
412
+ binomial(_k, _j)/_k, (_j, 0, _k), (_k, 1, 2*n + 1)))
413
+
414
+
415
+ def test_euler_odd():
416
+ n = Symbol('n', odd=True, positive=True)
417
+ assert euler(n) == 0
418
+ n = Symbol('n', odd=True)
419
+ assert euler(n) != 0
420
+
421
+
422
+ def test_euler_polynomials():
423
+ assert euler(0, x) == 1
424
+ assert euler(1, x) == x - S.Half
425
+ assert euler(2, x) == x**2 - x
426
+ assert euler(3, x) == x**3 - (3*x**2)/2 + Rational(1, 4)
427
+ m = Symbol('m')
428
+ assert isinstance(euler(m, x), euler)
429
+ from sympy.core.numbers import Float
430
+ A = Float('-0.46237208575048694923364757452876131e8') # from Maple
431
+ B = euler(19, S.Pi).evalf(32)
432
+ assert abs((A - B)/A) < 1e-31
433
+
434
+
435
+ def test_euler_polynomial_rewrite():
436
+ m = Symbol('m')
437
+ A = euler(m, x).rewrite('Sum');
438
+ assert A.subs({m:3, x:5}).doit() == euler(3, 5)
439
+
440
+
441
+ def test_catalan():
442
+ n = Symbol('n', integer=True)
443
+ m = Symbol('m', integer=True, positive=True)
444
+ k = Symbol('k', integer=True, nonnegative=True)
445
+ p = Symbol('p', nonnegative=True)
446
+
447
+ catalans = [1, 1, 2, 5, 14, 42, 132, 429, 1430, 4862, 16796, 58786]
448
+ for i, c in enumerate(catalans):
449
+ assert catalan(i) == c
450
+ assert catalan(n).rewrite(factorial).subs(n, i) == c
451
+ assert catalan(n).rewrite(Product).subs(n, i).doit() == c
452
+
453
+ assert unchanged(catalan, x)
454
+ assert catalan(2*x).rewrite(binomial) == binomial(4*x, 2*x)/(2*x + 1)
455
+ assert catalan(S.Half).rewrite(gamma) == 8/(3*pi)
456
+ assert catalan(S.Half).rewrite(factorial).rewrite(gamma) ==\
457
+ 8 / (3 * pi)
458
+ assert catalan(3*x).rewrite(gamma) == 4**(
459
+ 3*x)*gamma(3*x + S.Half)/(sqrt(pi)*gamma(3*x + 2))
460
+ assert catalan(x).rewrite(hyper) == hyper((-x + 1, -x), (2,), 1)
461
+
462
+ assert catalan(n).rewrite(factorial) == factorial(2*n) / (factorial(n + 1)
463
+ * factorial(n))
464
+ assert isinstance(catalan(n).rewrite(Product), catalan)
465
+ assert isinstance(catalan(m).rewrite(Product), Product)
466
+
467
+ assert diff(catalan(x), x) == (polygamma(
468
+ 0, x + S.Half) - polygamma(0, x + 2) + log(4))*catalan(x)
469
+
470
+ assert catalan(x).evalf() == catalan(x)
471
+ c = catalan(S.Half).evalf()
472
+ assert str(c) == '0.848826363156775'
473
+ c = catalan(I).evalf(3)
474
+ assert str((re(c), im(c))) == '(0.398, -0.0209)'
475
+
476
+ # Assumptions
477
+ assert catalan(p).is_positive is True
478
+ assert catalan(k).is_integer is True
479
+ assert catalan(m+3).is_composite is True
480
+
481
+
482
+ def test_genocchi():
483
+ genocchis = [0, -1, -1, 0, 1, 0, -3, 0, 17]
484
+ for n, g in enumerate(genocchis):
485
+ assert genocchi(n) == g
486
+
487
+ m = Symbol('m', integer=True)
488
+ n = Symbol('n', integer=True, positive=True)
489
+ assert unchanged(genocchi, m)
490
+ assert genocchi(2*n + 1) == 0
491
+ gn = 2 * (1 - 2**n) * bernoulli(n)
492
+ assert genocchi(n).rewrite(bernoulli).factor() == gn.factor()
493
+ gnx = 2 * (bernoulli(n, x) - 2**n * bernoulli(n, (x+1) / 2))
494
+ assert genocchi(n, x).rewrite(bernoulli).factor() == gnx.factor()
495
+ assert genocchi(2 * n).is_odd
496
+ assert genocchi(2 * n).is_even is False
497
+ assert genocchi(2 * n + 1).is_even
498
+ assert genocchi(n).is_integer
499
+ assert genocchi(4 * n).is_positive
500
+ # these are the only 2 prime Genocchi numbers
501
+ assert genocchi(6, evaluate=False).is_prime == S(-3).is_prime
502
+ assert genocchi(8, evaluate=False).is_prime
503
+ assert genocchi(4 * n + 2).is_negative
504
+ assert genocchi(4 * n + 1).is_negative is False
505
+ assert genocchi(4 * n - 2).is_negative
506
+
507
+ g0 = genocchi(0, evaluate=False)
508
+ assert g0.is_positive is False
509
+ assert g0.is_negative is False
510
+ assert g0.is_even is True
511
+ assert g0.is_odd is False
512
+
513
+ assert genocchi(0, x) == 0
514
+ assert genocchi(1, x) == -1
515
+ assert genocchi(2, x) == 1 - 2*x
516
+ assert genocchi(3, x) == 3*x - 3*x**2
517
+ assert genocchi(4, x) == -1 + 6*x**2 - 4*x**3
518
+ y = Symbol("y")
519
+ assert genocchi(5, (x+y)**100) == -5*(x+y)**400 + 10*(x+y)**300 - 5*(x+y)**100
520
+
521
+ assert str(genocchi(5.0, 4.0).evalf(n=10)) == '-660.0000000'
522
+ assert str(genocchi(Rational(5, 4)).evalf(n=10)) == '-1.104286457'
523
+ assert str(genocchi(-2).evalf(n=10)) == '3.606170709'
524
+ assert str(genocchi(1.3, 3.7).evalf(n=10)) == '-1.847375373'
525
+ assert str(genocchi(I, 1.0).evalf(n=10)) == '-0.3161917278 - 1.45311955*I'
526
+
527
+ n = Symbol('n')
528
+ assert genocchi(n, x).rewrite(dirichlet_eta) == -2*n * dirichlet_eta(1-n, x)
529
+
530
+
531
+ def test_andre():
532
+ nums = [1, 1, 1, 2, 5, 16, 61, 272, 1385, 7936, 50521]
533
+ for n, a in enumerate(nums):
534
+ assert andre(n) == a
535
+ assert andre(S.Infinity) == S.Infinity
536
+ assert andre(-1) == -log(2)
537
+ assert andre(-2) == -2*S.Catalan
538
+ assert andre(-3) == 3*zeta(3)/16
539
+ assert andre(-5) == -15*zeta(5)/256
540
+ # In fact andre(-2*n) is related to the Dirichlet *beta* function
541
+ # at 2*n, but SymPy doesn't implement that (or general L-functions)
542
+ assert unchanged(andre, -4)
543
+
544
+ n = Symbol('n', integer=True, nonnegative=True)
545
+ assert unchanged(andre, n)
546
+ assert andre(n).is_integer is True
547
+ assert andre(n).is_positive is True
548
+
549
+ assert str(andre(10, evaluate=False).evalf(n=10)) == '50521.00000'
550
+ assert str(andre(-1, evaluate=False).evalf(n=10)) == '-0.6931471806'
551
+ assert str(andre(-2, evaluate=False).evalf(n=10)) == '-1.831931188'
552
+ assert str(andre(-4, evaluate=False).evalf(n=10)) == '1.977889103'
553
+ assert str(andre(I, evaluate=False).evalf(n=10)) == '2.378417833 + 0.6343322845*I'
554
+
555
+ assert andre(x).rewrite(polylog) == \
556
+ (-I)**(x+1) * polylog(-x, I) + I**(x+1) * polylog(-x, -I)
557
+ assert andre(x).rewrite(zeta) == \
558
+ 2 * gamma(x+1) / (2*pi)**(x+1) * \
559
+ (zeta(x+1, Rational(1,4)) - cos(pi*x) * zeta(x+1, Rational(3,4)))
560
+
561
+
562
+ @nocache_fail
563
+ def test_partition():
564
+ partition_nums = [1, 1, 2, 3, 5, 7, 11, 15, 22]
565
+ for n, p in enumerate(partition_nums):
566
+ assert partition(n) == p
567
+
568
+ x = Symbol('x')
569
+ y = Symbol('y', real=True)
570
+ m = Symbol('m', integer=True)
571
+ n = Symbol('n', integer=True, negative=True)
572
+ p = Symbol('p', integer=True, nonnegative=True)
573
+ assert partition(m).is_integer
574
+ assert not partition(m).is_negative
575
+ assert partition(m).is_nonnegative
576
+ assert partition(n).is_zero
577
+ assert partition(p).is_positive
578
+ assert partition(x).subs(x, 7) == 15
579
+ assert partition(y).subs(y, 8) == 22
580
+ raises(ValueError, lambda: partition(Rational(5, 4)))
581
+
582
+
583
+ def test__nT():
584
+ assert [_nT(i, j) for i in range(5) for j in range(i + 2)] == [
585
+ 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 1, 2, 1, 1, 0]
586
+ check = [_nT(10, i) for i in range(11)]
587
+ assert check == [0, 1, 5, 8, 9, 7, 5, 3, 2, 1, 1]
588
+ assert all(type(i) is int for i in check)
589
+ assert _nT(10, 5) == 7
590
+ assert _nT(100, 98) == 2
591
+ assert _nT(100, 100) == 1
592
+ assert _nT(10, 3) == 8
593
+
594
+
595
+ def test_nC_nP_nT():
596
+ from sympy.utilities.iterables import (
597
+ multiset_permutations, multiset_combinations, multiset_partitions,
598
+ partitions, subsets, permutations)
599
+ from sympy.functions.combinatorial.numbers import (
600
+ nP, nC, nT, stirling, _stirling1, _stirling2, _multiset_histogram, _AOP_product)
601
+
602
+ from sympy.combinatorics.permutations import Permutation
603
+ from sympy.core.random import choice
604
+
605
+ c = string.ascii_lowercase
606
+ for i in range(100):
607
+ s = ''.join(choice(c) for i in range(7))
608
+ u = len(s) == len(set(s))
609
+ try:
610
+ tot = 0
611
+ for i in range(8):
612
+ check = nP(s, i)
613
+ tot += check
614
+ assert len(list(multiset_permutations(s, i))) == check
615
+ if u:
616
+ assert nP(len(s), i) == check
617
+ assert nP(s) == tot
618
+ except AssertionError:
619
+ print(s, i, 'failed perm test')
620
+ raise ValueError()
621
+
622
+ for i in range(100):
623
+ s = ''.join(choice(c) for i in range(7))
624
+ u = len(s) == len(set(s))
625
+ try:
626
+ tot = 0
627
+ for i in range(8):
628
+ check = nC(s, i)
629
+ tot += check
630
+ assert len(list(multiset_combinations(s, i))) == check
631
+ if u:
632
+ assert nC(len(s), i) == check
633
+ assert nC(s) == tot
634
+ if u:
635
+ assert nC(len(s)) == tot
636
+ except AssertionError:
637
+ print(s, i, 'failed combo test')
638
+ raise ValueError()
639
+
640
+ for i in range(1, 10):
641
+ tot = 0
642
+ for j in range(1, i + 2):
643
+ check = nT(i, j)
644
+ assert check.is_Integer
645
+ tot += check
646
+ assert sum(1 for p in partitions(i, j, size=True) if p[0] == j) == check
647
+ assert nT(i) == tot
648
+
649
+ for i in range(1, 10):
650
+ tot = 0
651
+ for j in range(1, i + 2):
652
+ check = nT(range(i), j)
653
+ tot += check
654
+ assert len(list(multiset_partitions(list(range(i)), j))) == check
655
+ assert nT(range(i)) == tot
656
+
657
+ for i in range(100):
658
+ s = ''.join(choice(c) for i in range(7))
659
+ u = len(s) == len(set(s))
660
+ try:
661
+ tot = 0
662
+ for i in range(1, 8):
663
+ check = nT(s, i)
664
+ tot += check
665
+ assert len(list(multiset_partitions(s, i))) == check
666
+ if u:
667
+ assert nT(range(len(s)), i) == check
668
+ if u:
669
+ assert nT(range(len(s))) == tot
670
+ assert nT(s) == tot
671
+ except AssertionError:
672
+ print(s, i, 'failed partition test')
673
+ raise ValueError()
674
+
675
+ # tests for Stirling numbers of the first kind that are not tested in the
676
+ # above
677
+ assert [stirling(9, i, kind=1) for i in range(11)] == [
678
+ 0, 40320, 109584, 118124, 67284, 22449, 4536, 546, 36, 1, 0]
679
+ perms = list(permutations(range(4)))
680
+ assert [sum(1 for p in perms if Permutation(p).cycles == i)
681
+ for i in range(5)] == [0, 6, 11, 6, 1] == [
682
+ stirling(4, i, kind=1) for i in range(5)]
683
+ # http://oeis.org/A008275
684
+ assert [stirling(n, k, signed=1)
685
+ for n in range(10) for k in range(1, n + 1)] == [
686
+ 1, -1,
687
+ 1, 2, -3,
688
+ 1, -6, 11, -6,
689
+ 1, 24, -50, 35, -10,
690
+ 1, -120, 274, -225, 85, -15,
691
+ 1, 720, -1764, 1624, -735, 175, -21,
692
+ 1, -5040, 13068, -13132, 6769, -1960, 322, -28,
693
+ 1, 40320, -109584, 118124, -67284, 22449, -4536, 546, -36, 1]
694
+ # https://en.wikipedia.org/wiki/Stirling_numbers_of_the_first_kind
695
+ assert [stirling(n, k, kind=1)
696
+ for n in range(10) for k in range(n+1)] == [
697
+ 1,
698
+ 0, 1,
699
+ 0, 1, 1,
700
+ 0, 2, 3, 1,
701
+ 0, 6, 11, 6, 1,
702
+ 0, 24, 50, 35, 10, 1,
703
+ 0, 120, 274, 225, 85, 15, 1,
704
+ 0, 720, 1764, 1624, 735, 175, 21, 1,
705
+ 0, 5040, 13068, 13132, 6769, 1960, 322, 28, 1,
706
+ 0, 40320, 109584, 118124, 67284, 22449, 4536, 546, 36, 1]
707
+ # https://en.wikipedia.org/wiki/Stirling_numbers_of_the_second_kind
708
+ assert [stirling(n, k, kind=2)
709
+ for n in range(10) for k in range(n+1)] == [
710
+ 1,
711
+ 0, 1,
712
+ 0, 1, 1,
713
+ 0, 1, 3, 1,
714
+ 0, 1, 7, 6, 1,
715
+ 0, 1, 15, 25, 10, 1,
716
+ 0, 1, 31, 90, 65, 15, 1,
717
+ 0, 1, 63, 301, 350, 140, 21, 1,
718
+ 0, 1, 127, 966, 1701, 1050, 266, 28, 1,
719
+ 0, 1, 255, 3025, 7770, 6951, 2646, 462, 36, 1]
720
+ assert stirling(3, 4, kind=1) == stirling(3, 4, kind=1) == 0
721
+ raises(ValueError, lambda: stirling(-2, 2))
722
+
723
+ # Assertion that the return type is SymPy Integer.
724
+ assert isinstance(_stirling1(6, 3), Integer)
725
+ assert isinstance(_stirling2(6, 3), Integer)
726
+
727
+ def delta(p):
728
+ if len(p) == 1:
729
+ return oo
730
+ return min(abs(i[0] - i[1]) for i in subsets(p, 2))
731
+ parts = multiset_partitions(range(5), 3)
732
+ d = 2
733
+ assert (sum(1 for p in parts if all(delta(i) >= d for i in p)) ==
734
+ stirling(5, 3, d=d) == 7)
735
+
736
+ # other coverage tests
737
+ assert nC('abb', 2) == nC('aab', 2) == 2
738
+ assert nP(3, 3, replacement=True) == nP('aabc', 3, replacement=True) == 27
739
+ assert nP(3, 4) == 0
740
+ assert nP('aabc', 5) == 0
741
+ assert nC(4, 2, replacement=True) == nC('abcdd', 2, replacement=True) == \
742
+ len(list(multiset_combinations('aabbccdd', 2))) == 10
743
+ assert nC('abcdd') == sum(nC('abcdd', i) for i in range(6)) == 24
744
+ assert nC(list('abcdd'), 4) == 4
745
+ assert nT('aaaa') == nT(4) == len(list(partitions(4))) == 5
746
+ assert nT('aaab') == len(list(multiset_partitions('aaab'))) == 7
747
+ assert nC('aabb'*3, 3) == 4 # aaa, bbb, abb, baa
748
+ assert dict(_AOP_product((4,1,1,1))) == {
749
+ 0: 1, 1: 4, 2: 7, 3: 8, 4: 8, 5: 7, 6: 4, 7: 1}
750
+ # the following was the first t that showed a problem in a previous form of
751
+ # the function, so it's not as random as it may appear
752
+ t = (3, 9, 4, 6, 6, 5, 5, 2, 10, 4)
753
+ assert sum(_AOP_product(t)[i] for i in range(55)) == 58212000
754
+ raises(ValueError, lambda: _multiset_histogram({1:'a'}))
755
+
756
+
757
+ def test_PR_14617():
758
+ from sympy.functions.combinatorial.numbers import nT
759
+ for n in (0, []):
760
+ for k in (-1, 0, 1):
761
+ if k == 0:
762
+ assert nT(n, k) == 1
763
+ else:
764
+ assert nT(n, k) == 0
765
+
766
+
767
+ def test_issue_8496():
768
+ n = Symbol("n")
769
+ k = Symbol("k")
770
+
771
+ raises(TypeError, lambda: catalan(n, k))
772
+
773
+
774
+ def test_issue_8601():
775
+ n = Symbol('n', integer=True, negative=True)
776
+
777
+ assert catalan(n - 1) is S.Zero
778
+ assert catalan(Rational(-1, 2)) is S.ComplexInfinity
779
+ assert catalan(-S.One) == Rational(-1, 2)
780
+ c1 = catalan(-5.6).evalf()
781
+ assert str(c1) == '6.93334070531408e-5'
782
+ c2 = catalan(-35.4).evalf()
783
+ assert str(c2) == '-4.14189164517449e-24'
784
+
785
+
786
+ def test_motzkin():
787
+ assert motzkin.is_motzkin(4) == True
788
+ assert motzkin.is_motzkin(9) == True
789
+ assert motzkin.is_motzkin(10) == False
790
+ assert motzkin.find_motzkin_numbers_in_range(10,200) == [21, 51, 127]
791
+ assert motzkin.find_motzkin_numbers_in_range(10,400) == [21, 51, 127, 323]
792
+ assert motzkin.find_motzkin_numbers_in_range(10,1600) == [21, 51, 127, 323, 835]
793
+ assert motzkin.find_first_n_motzkins(5) == [1, 1, 2, 4, 9]
794
+ assert motzkin.find_first_n_motzkins(7) == [1, 1, 2, 4, 9, 21, 51]
795
+ assert motzkin.find_first_n_motzkins(10) == [1, 1, 2, 4, 9, 21, 51, 127, 323, 835]
796
+ raises(ValueError, lambda: motzkin.eval(77.58))
797
+ raises(ValueError, lambda: motzkin.eval(-8))
798
+ raises(ValueError, lambda: motzkin.find_motzkin_numbers_in_range(-2,7))
799
+ raises(ValueError, lambda: motzkin.find_motzkin_numbers_in_range(13,7))
800
+ raises(ValueError, lambda: motzkin.find_first_n_motzkins(112.8))
801
+
802
+
803
+ def test_nD_derangements():
804
+ from sympy.utilities.iterables import (partitions, multiset,
805
+ multiset_derangements, multiset_permutations)
806
+ from sympy.functions.combinatorial.numbers import nD
807
+
808
+ got = []
809
+ for i in partitions(8, k=4):
810
+ s = []
811
+ it = 0
812
+ for k, v in i.items():
813
+ for i in range(v):
814
+ s.extend([it]*k)
815
+ it += 1
816
+ ms = multiset(s)
817
+ c1 = sum(1 for i in multiset_permutations(s) if
818
+ all(i != j for i, j in zip(i, s)))
819
+ assert c1 == nD(ms) == nD(ms, 0) == nD(ms, 1)
820
+ v = [tuple(i) for i in multiset_derangements(s)]
821
+ c2 = len(v)
822
+ assert c2 == len(set(v))
823
+ assert c1 == c2
824
+ got.append(c1)
825
+ assert got == [1, 4, 6, 12, 24, 24, 61, 126, 315, 780, 297, 772,
826
+ 2033, 5430, 14833]
827
+
828
+ assert nD('1112233456', brute=True) == nD('1112233456') == 16356
829
+ assert nD('') == nD([]) == nD({}) == 0
830
+ assert nD({1: 0}) == 0
831
+ raises(ValueError, lambda: nD({1: -1}))
832
+ assert nD('112') == 0
833
+ assert nD(i='112') == 0
834
+ assert [nD(n=i) for i in range(6)] == [0, 0, 1, 2, 9, 44]
835
+ assert nD((i for i in range(4))) == nD('0123') == 9
836
+ assert nD(m=(i for i in range(4))) == 3
837
+ assert nD(m={0: 1, 1: 1, 2: 1, 3: 1}) == 3
838
+ assert nD(m=[0, 1, 2, 3]) == 3
839
+ raises(TypeError, lambda: nD(m=0))
840
+ raises(TypeError, lambda: nD(-1))
841
+ assert nD({-1: 1, -2: 1}) == 1
842
+ assert nD(m={0: 3}) == 0
843
+ raises(ValueError, lambda: nD(i='123', n=3))
844
+ raises(ValueError, lambda: nD(i='123', m=(1,2)))
845
+ raises(ValueError, lambda: nD(n=0, m=(1,2)))
846
+ raises(ValueError, lambda: nD({1: -1}))
847
+ raises(ValueError, lambda: nD(m={-1: 1, 2: 1}))
848
+ raises(ValueError, lambda: nD(m={1: -1, 2: 1}))
849
+ raises(ValueError, lambda: nD(m=[-1, 2]))
850
+ raises(TypeError, lambda: nD({1: x}))
851
+ raises(TypeError, lambda: nD(m={1: x}))
852
+ raises(TypeError, lambda: nD(m={x: 1}))
venv/lib/python3.10/site-packages/sympy/functions/elementary/__init__.py ADDED
@@ -0,0 +1 @@
 
 
1
+ # Stub __init__.py for sympy.functions.elementary
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venv/lib/python3.10/site-packages/sympy/functions/elementary/_trigonometric_special.py ADDED
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1
+ r"""A module for special angle forumlas for trigonometric functions
2
+
3
+ TODO
4
+ ====
5
+
6
+ This module should be developed in the future to contain direct squrae root
7
+ representation of
8
+
9
+ .. math
10
+ F(\frac{n}{m} \pi)
11
+
12
+ for every
13
+
14
+ - $m \in \{ 3, 5, 17, 257, 65537 \}$
15
+ - $n \in \mathbb{N}$, $0 \le n < m$
16
+ - $F \in \{\sin, \cos, \tan, \csc, \sec, \cot\}$
17
+
18
+ Without multi-step rewrites
19
+ (e.g. $\tan \to \cos/\sin \to \cos/\sqrt \to \ sqrt$)
20
+ or using chebyshev identities
21
+ (e.g. $\cos \to \cos + \cos^2 + \cdots \to \sqrt{} + \sqrt{}^2 + \cdots $),
22
+ which are trivial to implement in sympy,
23
+ and had used to give overly complicated expressions.
24
+
25
+ The reference can be found below, if anyone may need help implementing them.
26
+
27
+ References
28
+ ==========
29
+
30
+ .. [*] Gottlieb, Christian. (1999). The Simple and straightforward construction
31
+ of the regular 257-gon. The Mathematical Intelligencer. 21. 31-37.
32
+ 10.1007/BF03024829.
33
+ .. [*] https://resources.wolframcloud.com/FunctionRepository/resources/Cos2PiOverFermatPrime
34
+ """
35
+ from __future__ import annotations
36
+ from typing import Callable
37
+ from functools import reduce
38
+ from sympy.core.expr import Expr
39
+ from sympy.core.singleton import S
40
+ from sympy.core.numbers import igcdex, Integer
41
+ from sympy.functions.elementary.miscellaneous import sqrt
42
+ from sympy.core.cache import cacheit
43
+
44
+
45
+ def migcdex(*x: int) -> tuple[tuple[int, ...], int]:
46
+ r"""Compute extended gcd for multiple integers.
47
+
48
+ Explanation
49
+ ===========
50
+
51
+ Given the integers $x_1, \cdots, x_n$ and
52
+ an extended gcd for multiple arguments are defined as a solution
53
+ $(y_1, \cdots, y_n), g$ for the diophantine equation
54
+ $x_1 y_1 + \cdots + x_n y_n = g$ such that
55
+ $g = \gcd(x_1, \cdots, x_n)$.
56
+
57
+ Examples
58
+ ========
59
+
60
+ >>> from sympy.functions.elementary._trigonometric_special import migcdex
61
+ >>> migcdex()
62
+ ((), 0)
63
+ >>> migcdex(4)
64
+ ((1,), 4)
65
+ >>> migcdex(4, 6)
66
+ ((-1, 1), 2)
67
+ >>> migcdex(6, 10, 15)
68
+ ((1, 1, -1), 1)
69
+ """
70
+ if not x:
71
+ return (), 0
72
+
73
+ if len(x) == 1:
74
+ return (1,), x[0]
75
+
76
+ if len(x) == 2:
77
+ u, v, h = igcdex(x[0], x[1])
78
+ return (u, v), h
79
+
80
+ y, g = migcdex(*x[1:])
81
+ u, v, h = igcdex(x[0], g)
82
+ return (u, *(v * i for i in y)), h
83
+
84
+
85
+ def ipartfrac(*denoms: int) -> tuple[int, ...]:
86
+ r"""Compute the the partial fraction decomposition.
87
+
88
+ Explanation
89
+ ===========
90
+
91
+ Given a rational number $\frac{1}{q_1 \cdots q_n}$ where all
92
+ $q_1, \cdots, q_n$ are pairwise coprime,
93
+
94
+ A partial fraction decomposition is defined as
95
+
96
+ .. math::
97
+ \frac{1}{q_1 \cdots q_n} = \frac{p_1}{q_1} + \cdots + \frac{p_n}{q_n}
98
+
99
+ And it can be derived from solving the following diophantine equation for
100
+ the $p_1, \cdots, p_n$
101
+
102
+ .. math::
103
+ 1 = p_1 \prod_{i \ne 1}q_i + \cdots + p_n \prod_{i \ne n}q_i
104
+
105
+ Where $q_1, \cdots, q_n$ being pairwise coprime implies
106
+ $\gcd(\prod_{i \ne 1}q_i, \cdots, \prod_{i \ne n}q_i) = 1$,
107
+ which guarantees the existance of the solution.
108
+
109
+ It is sufficient to compute partial fraction decomposition only
110
+ for numerator $1$ because partial fraction decomposition for any
111
+ $\frac{n}{q_1 \cdots q_n}$ can be easily computed by multiplying
112
+ the result by $n$ afterwards.
113
+
114
+ Parameters
115
+ ==========
116
+
117
+ denoms : int
118
+ The pairwise coprime integer denominators $q_i$ which defines the
119
+ rational number $\frac{1}{q_1 \cdots q_n}$
120
+
121
+ Returns
122
+ =======
123
+
124
+ tuple[int, ...]
125
+ The list of numerators which semantically corresponds to $p_i$ of the
126
+ partial fraction decomposition
127
+ $\frac{1}{q_1 \cdots q_n} = \frac{p_1}{q_1} + \cdots + \frac{p_n}{q_n}$
128
+
129
+ Examples
130
+ ========
131
+
132
+ >>> from sympy import Rational, Mul
133
+ >>> from sympy.functions.elementary._trigonometric_special import ipartfrac
134
+
135
+ >>> denoms = 2, 3, 5
136
+ >>> numers = ipartfrac(2, 3, 5)
137
+ >>> numers
138
+ (1, 7, -14)
139
+
140
+ >>> Rational(1, Mul(*denoms))
141
+ 1/30
142
+ >>> out = 0
143
+ >>> for n, d in zip(numers, denoms):
144
+ ... out += Rational(n, d)
145
+ >>> out
146
+ 1/30
147
+ """
148
+ if not denoms:
149
+ return ()
150
+
151
+ def mul(x: int, y: int) -> int:
152
+ return x * y
153
+
154
+ denom = reduce(mul, denoms)
155
+ a = [denom // x for x in denoms]
156
+ h, _ = migcdex(*a)
157
+ return h
158
+
159
+
160
+ def fermat_coords(n: int) -> list[int] | None:
161
+ """If n can be factored in terms of Fermat primes with
162
+ multiplicity of each being 1, return those primes, else
163
+ None
164
+ """
165
+ primes = []
166
+ for p in [3, 5, 17, 257, 65537]:
167
+ quotient, remainder = divmod(n, p)
168
+ if remainder == 0:
169
+ n = quotient
170
+ primes.append(p)
171
+ if n == 1:
172
+ return primes
173
+ return None
174
+
175
+
176
+ @cacheit
177
+ def cos_3() -> Expr:
178
+ r"""Computes $\cos \frac{\pi}{3}$ in square roots"""
179
+ return S.Half
180
+
181
+
182
+ @cacheit
183
+ def cos_5() -> Expr:
184
+ r"""Computes $\cos \frac{\pi}{5}$ in square roots"""
185
+ return (sqrt(5) + 1) / 4
186
+
187
+
188
+ @cacheit
189
+ def cos_17() -> Expr:
190
+ r"""Computes $\cos \frac{\pi}{17}$ in square roots"""
191
+ return sqrt(
192
+ (15 + sqrt(17)) / 32 + sqrt(2) * (sqrt(17 - sqrt(17)) +
193
+ sqrt(sqrt(2) * (-8 * sqrt(17 + sqrt(17)) - (1 - sqrt(17))
194
+ * sqrt(17 - sqrt(17))) + 6 * sqrt(17) + 34)) / 32)
195
+
196
+
197
+ @cacheit
198
+ def cos_257() -> Expr:
199
+ r"""Computes $\cos \frac{\pi}{257}$ in square roots
200
+
201
+ References
202
+ ==========
203
+
204
+ .. [*] https://math.stackexchange.com/questions/516142/how-does-cos2-pi-257-look-like-in-real-radicals
205
+ .. [*] https://r-knott.surrey.ac.uk/Fibonacci/simpleTrig.html
206
+ """
207
+ def f1(a: Expr, b: Expr) -> tuple[Expr, Expr]:
208
+ return (a + sqrt(a**2 + b)) / 2, (a - sqrt(a**2 + b)) / 2
209
+
210
+ def f2(a: Expr, b: Expr) -> Expr:
211
+ return (a - sqrt(a**2 + b))/2
212
+
213
+ t1, t2 = f1(S.NegativeOne, Integer(256))
214
+ z1, z3 = f1(t1, Integer(64))
215
+ z2, z4 = f1(t2, Integer(64))
216
+ y1, y5 = f1(z1, 4*(5 + t1 + 2*z1))
217
+ y6, y2 = f1(z2, 4*(5 + t2 + 2*z2))
218
+ y3, y7 = f1(z3, 4*(5 + t1 + 2*z3))
219
+ y8, y4 = f1(z4, 4*(5 + t2 + 2*z4))
220
+ x1, x9 = f1(y1, -4*(t1 + y1 + y3 + 2*y6))
221
+ x2, x10 = f1(y2, -4*(t2 + y2 + y4 + 2*y7))
222
+ x3, x11 = f1(y3, -4*(t1 + y3 + y5 + 2*y8))
223
+ x4, x12 = f1(y4, -4*(t2 + y4 + y6 + 2*y1))
224
+ x5, x13 = f1(y5, -4*(t1 + y5 + y7 + 2*y2))
225
+ x6, x14 = f1(y6, -4*(t2 + y6 + y8 + 2*y3))
226
+ x15, x7 = f1(y7, -4*(t1 + y7 + y1 + 2*y4))
227
+ x8, x16 = f1(y8, -4*(t2 + y8 + y2 + 2*y5))
228
+ v1 = f2(x1, -4*(x1 + x2 + x3 + x6))
229
+ v2 = f2(x2, -4*(x2 + x3 + x4 + x7))
230
+ v3 = f2(x8, -4*(x8 + x9 + x10 + x13))
231
+ v4 = f2(x9, -4*(x9 + x10 + x11 + x14))
232
+ v5 = f2(x10, -4*(x10 + x11 + x12 + x15))
233
+ v6 = f2(x16, -4*(x16 + x1 + x2 + x5))
234
+ u1 = -f2(-v1, -4*(v2 + v3))
235
+ u2 = -f2(-v4, -4*(v5 + v6))
236
+ w1 = -2*f2(-u1, -4*u2)
237
+ return sqrt(sqrt(2)*sqrt(w1 + 4)/8 + S.Half)
238
+
239
+
240
+ def cos_table() -> dict[int, Callable[[], Expr]]:
241
+ r"""Lazily evaluated table for $\cos \frac{\pi}{n}$ in square roots for
242
+ $n \in \{3, 5, 17, 257, 65537\}$.
243
+
244
+ Notes
245
+ =====
246
+
247
+ 65537 is the only other known Fermat prime and it is nearly impossible to
248
+ build in the current SymPy due to performance issues.
249
+
250
+ References
251
+ ==========
252
+
253
+ https://r-knott.surrey.ac.uk/Fibonacci/simpleTrig.html
254
+ """
255
+ return {
256
+ 3: cos_3,
257
+ 5: cos_5,
258
+ 17: cos_17,
259
+ 257: cos_257
260
+ }
venv/lib/python3.10/site-packages/sympy/functions/elementary/benchmarks/__init__.py ADDED
File without changes
venv/lib/python3.10/site-packages/sympy/functions/elementary/benchmarks/__pycache__/__init__.cpython-310.pyc ADDED
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venv/lib/python3.10/site-packages/sympy/functions/elementary/benchmarks/__pycache__/bench_exp.cpython-310.pyc ADDED
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venv/lib/python3.10/site-packages/sympy/functions/elementary/benchmarks/bench_exp.py ADDED
@@ -0,0 +1,11 @@
 
 
 
 
 
 
 
 
 
 
 
 
1
+ from sympy.core.symbol import symbols
2
+ from sympy.functions.elementary.exponential import exp
3
+
4
+ x, y = symbols('x,y')
5
+
6
+ e = exp(2*x)
7
+ q = exp(3*x)
8
+
9
+
10
+ def timeit_exp_subs():
11
+ e.subs(q, y)
venv/lib/python3.10/site-packages/sympy/functions/elementary/complexes.py ADDED
@@ -0,0 +1,1465 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ from typing import Tuple as tTuple
2
+
3
+ from sympy.core import S, Add, Mul, sympify, Symbol, Dummy, Basic
4
+ from sympy.core.expr import Expr
5
+ from sympy.core.exprtools import factor_terms
6
+ from sympy.core.function import (Function, Derivative, ArgumentIndexError,
7
+ AppliedUndef, expand_mul)
8
+ from sympy.core.logic import fuzzy_not, fuzzy_or
9
+ from sympy.core.numbers import pi, I, oo
10
+ from sympy.core.power import Pow
11
+ from sympy.core.relational import Eq
12
+ from sympy.functions.elementary.miscellaneous import sqrt
13
+ from sympy.functions.elementary.piecewise import Piecewise
14
+
15
+ ###############################################################################
16
+ ######################### REAL and IMAGINARY PARTS ############################
17
+ ###############################################################################
18
+
19
+
20
+ class re(Function):
21
+ """
22
+ Returns real part of expression. This function performs only
23
+ elementary analysis and so it will fail to decompose properly
24
+ more complicated expressions. If completely simplified result
25
+ is needed then use ``Basic.as_real_imag()`` or perform complex
26
+ expansion on instance of this function.
27
+
28
+ Examples
29
+ ========
30
+
31
+ >>> from sympy import re, im, I, E, symbols
32
+ >>> x, y = symbols('x y', real=True)
33
+ >>> re(2*E)
34
+ 2*E
35
+ >>> re(2*I + 17)
36
+ 17
37
+ >>> re(2*I)
38
+ 0
39
+ >>> re(im(x) + x*I + 2)
40
+ 2
41
+ >>> re(5 + I + 2)
42
+ 7
43
+
44
+ Parameters
45
+ ==========
46
+
47
+ arg : Expr
48
+ Real or complex expression.
49
+
50
+ Returns
51
+ =======
52
+
53
+ expr : Expr
54
+ Real part of expression.
55
+
56
+ See Also
57
+ ========
58
+
59
+ im
60
+ """
61
+
62
+ args: tTuple[Expr]
63
+
64
+ is_extended_real = True
65
+ unbranched = True # implicitly works on the projection to C
66
+ _singularities = True # non-holomorphic
67
+
68
+ @classmethod
69
+ def eval(cls, arg):
70
+ if arg is S.NaN:
71
+ return S.NaN
72
+ elif arg is S.ComplexInfinity:
73
+ return S.NaN
74
+ elif arg.is_extended_real:
75
+ return arg
76
+ elif arg.is_imaginary or (I*arg).is_extended_real:
77
+ return S.Zero
78
+ elif arg.is_Matrix:
79
+ return arg.as_real_imag()[0]
80
+ elif arg.is_Function and isinstance(arg, conjugate):
81
+ return re(arg.args[0])
82
+ else:
83
+
84
+ included, reverted, excluded = [], [], []
85
+ args = Add.make_args(arg)
86
+ for term in args:
87
+ coeff = term.as_coefficient(I)
88
+
89
+ if coeff is not None:
90
+ if not coeff.is_extended_real:
91
+ reverted.append(coeff)
92
+ elif not term.has(I) and term.is_extended_real:
93
+ excluded.append(term)
94
+ else:
95
+ # Try to do some advanced expansion. If
96
+ # impossible, don't try to do re(arg) again
97
+ # (because this is what we are trying to do now).
98
+ real_imag = term.as_real_imag(ignore=arg)
99
+ if real_imag:
100
+ excluded.append(real_imag[0])
101
+ else:
102
+ included.append(term)
103
+
104
+ if len(args) != len(included):
105
+ a, b, c = (Add(*xs) for xs in [included, reverted, excluded])
106
+
107
+ return cls(a) - im(b) + c
108
+
109
+ def as_real_imag(self, deep=True, **hints):
110
+ """
111
+ Returns the real number with a zero imaginary part.
112
+
113
+ """
114
+ return (self, S.Zero)
115
+
116
+ def _eval_derivative(self, x):
117
+ if x.is_extended_real or self.args[0].is_extended_real:
118
+ return re(Derivative(self.args[0], x, evaluate=True))
119
+ if x.is_imaginary or self.args[0].is_imaginary:
120
+ return -I \
121
+ * im(Derivative(self.args[0], x, evaluate=True))
122
+
123
+ def _eval_rewrite_as_im(self, arg, **kwargs):
124
+ return self.args[0] - I*im(self.args[0])
125
+
126
+ def _eval_is_algebraic(self):
127
+ return self.args[0].is_algebraic
128
+
129
+ def _eval_is_zero(self):
130
+ # is_imaginary implies nonzero
131
+ return fuzzy_or([self.args[0].is_imaginary, self.args[0].is_zero])
132
+
133
+ def _eval_is_finite(self):
134
+ if self.args[0].is_finite:
135
+ return True
136
+
137
+ def _eval_is_complex(self):
138
+ if self.args[0].is_finite:
139
+ return True
140
+
141
+
142
+ class im(Function):
143
+ """
144
+ Returns imaginary part of expression. This function performs only
145
+ elementary analysis and so it will fail to decompose properly more
146
+ complicated expressions. If completely simplified result is needed then
147
+ use ``Basic.as_real_imag()`` or perform complex expansion on instance of
148
+ this function.
149
+
150
+ Examples
151
+ ========
152
+
153
+ >>> from sympy import re, im, E, I
154
+ >>> from sympy.abc import x, y
155
+ >>> im(2*E)
156
+ 0
157
+ >>> im(2*I + 17)
158
+ 2
159
+ >>> im(x*I)
160
+ re(x)
161
+ >>> im(re(x) + y)
162
+ im(y)
163
+ >>> im(2 + 3*I)
164
+ 3
165
+
166
+ Parameters
167
+ ==========
168
+
169
+ arg : Expr
170
+ Real or complex expression.
171
+
172
+ Returns
173
+ =======
174
+
175
+ expr : Expr
176
+ Imaginary part of expression.
177
+
178
+ See Also
179
+ ========
180
+
181
+ re
182
+ """
183
+
184
+ args: tTuple[Expr]
185
+
186
+ is_extended_real = True
187
+ unbranched = True # implicitly works on the projection to C
188
+ _singularities = True # non-holomorphic
189
+
190
+ @classmethod
191
+ def eval(cls, arg):
192
+ if arg is S.NaN:
193
+ return S.NaN
194
+ elif arg is S.ComplexInfinity:
195
+ return S.NaN
196
+ elif arg.is_extended_real:
197
+ return S.Zero
198
+ elif arg.is_imaginary or (I*arg).is_extended_real:
199
+ return -I * arg
200
+ elif arg.is_Matrix:
201
+ return arg.as_real_imag()[1]
202
+ elif arg.is_Function and isinstance(arg, conjugate):
203
+ return -im(arg.args[0])
204
+ else:
205
+ included, reverted, excluded = [], [], []
206
+ args = Add.make_args(arg)
207
+ for term in args:
208
+ coeff = term.as_coefficient(I)
209
+
210
+ if coeff is not None:
211
+ if not coeff.is_extended_real:
212
+ reverted.append(coeff)
213
+ else:
214
+ excluded.append(coeff)
215
+ elif term.has(I) or not term.is_extended_real:
216
+ # Try to do some advanced expansion. If
217
+ # impossible, don't try to do im(arg) again
218
+ # (because this is what we are trying to do now).
219
+ real_imag = term.as_real_imag(ignore=arg)
220
+ if real_imag:
221
+ excluded.append(real_imag[1])
222
+ else:
223
+ included.append(term)
224
+
225
+ if len(args) != len(included):
226
+ a, b, c = (Add(*xs) for xs in [included, reverted, excluded])
227
+
228
+ return cls(a) + re(b) + c
229
+
230
+ def as_real_imag(self, deep=True, **hints):
231
+ """
232
+ Return the imaginary part with a zero real part.
233
+
234
+ """
235
+ return (self, S.Zero)
236
+
237
+ def _eval_derivative(self, x):
238
+ if x.is_extended_real or self.args[0].is_extended_real:
239
+ return im(Derivative(self.args[0], x, evaluate=True))
240
+ if x.is_imaginary or self.args[0].is_imaginary:
241
+ return -I \
242
+ * re(Derivative(self.args[0], x, evaluate=True))
243
+
244
+ def _eval_rewrite_as_re(self, arg, **kwargs):
245
+ return -I*(self.args[0] - re(self.args[0]))
246
+
247
+ def _eval_is_algebraic(self):
248
+ return self.args[0].is_algebraic
249
+
250
+ def _eval_is_zero(self):
251
+ return self.args[0].is_extended_real
252
+
253
+ def _eval_is_finite(self):
254
+ if self.args[0].is_finite:
255
+ return True
256
+
257
+ def _eval_is_complex(self):
258
+ if self.args[0].is_finite:
259
+ return True
260
+
261
+ ###############################################################################
262
+ ############### SIGN, ABSOLUTE VALUE, ARGUMENT and CONJUGATION ################
263
+ ###############################################################################
264
+
265
+ class sign(Function):
266
+ """
267
+ Returns the complex sign of an expression:
268
+
269
+ Explanation
270
+ ===========
271
+
272
+ If the expression is real the sign will be:
273
+
274
+ * $1$ if expression is positive
275
+ * $0$ if expression is equal to zero
276
+ * $-1$ if expression is negative
277
+
278
+ If the expression is imaginary the sign will be:
279
+
280
+ * $I$ if im(expression) is positive
281
+ * $-I$ if im(expression) is negative
282
+
283
+ Otherwise an unevaluated expression will be returned. When evaluated, the
284
+ result (in general) will be ``cos(arg(expr)) + I*sin(arg(expr))``.
285
+
286
+ Examples
287
+ ========
288
+
289
+ >>> from sympy import sign, I
290
+
291
+ >>> sign(-1)
292
+ -1
293
+ >>> sign(0)
294
+ 0
295
+ >>> sign(-3*I)
296
+ -I
297
+ >>> sign(1 + I)
298
+ sign(1 + I)
299
+ >>> _.evalf()
300
+ 0.707106781186548 + 0.707106781186548*I
301
+
302
+ Parameters
303
+ ==========
304
+
305
+ arg : Expr
306
+ Real or imaginary expression.
307
+
308
+ Returns
309
+ =======
310
+
311
+ expr : Expr
312
+ Complex sign of expression.
313
+
314
+ See Also
315
+ ========
316
+
317
+ Abs, conjugate
318
+ """
319
+
320
+ is_complex = True
321
+ _singularities = True
322
+
323
+ def doit(self, **hints):
324
+ s = super().doit()
325
+ if s == self and self.args[0].is_zero is False:
326
+ return self.args[0] / Abs(self.args[0])
327
+ return s
328
+
329
+ @classmethod
330
+ def eval(cls, arg):
331
+ # handle what we can
332
+ if arg.is_Mul:
333
+ c, args = arg.as_coeff_mul()
334
+ unk = []
335
+ s = sign(c)
336
+ for a in args:
337
+ if a.is_extended_negative:
338
+ s = -s
339
+ elif a.is_extended_positive:
340
+ pass
341
+ else:
342
+ if a.is_imaginary:
343
+ ai = im(a)
344
+ if ai.is_comparable: # i.e. a = I*real
345
+ s *= I
346
+ if ai.is_extended_negative:
347
+ # can't use sign(ai) here since ai might not be
348
+ # a Number
349
+ s = -s
350
+ else:
351
+ unk.append(a)
352
+ else:
353
+ unk.append(a)
354
+ if c is S.One and len(unk) == len(args):
355
+ return None
356
+ return s * cls(arg._new_rawargs(*unk))
357
+ if arg is S.NaN:
358
+ return S.NaN
359
+ if arg.is_zero: # it may be an Expr that is zero
360
+ return S.Zero
361
+ if arg.is_extended_positive:
362
+ return S.One
363
+ if arg.is_extended_negative:
364
+ return S.NegativeOne
365
+ if arg.is_Function:
366
+ if isinstance(arg, sign):
367
+ return arg
368
+ if arg.is_imaginary:
369
+ if arg.is_Pow and arg.exp is S.Half:
370
+ # we catch this because non-trivial sqrt args are not expanded
371
+ # e.g. sqrt(1-sqrt(2)) --x--> to I*sqrt(sqrt(2) - 1)
372
+ return I
373
+ arg2 = -I * arg
374
+ if arg2.is_extended_positive:
375
+ return I
376
+ if arg2.is_extended_negative:
377
+ return -I
378
+
379
+ def _eval_Abs(self):
380
+ if fuzzy_not(self.args[0].is_zero):
381
+ return S.One
382
+
383
+ def _eval_conjugate(self):
384
+ return sign(conjugate(self.args[0]))
385
+
386
+ def _eval_derivative(self, x):
387
+ if self.args[0].is_extended_real:
388
+ from sympy.functions.special.delta_functions import DiracDelta
389
+ return 2 * Derivative(self.args[0], x, evaluate=True) \
390
+ * DiracDelta(self.args[0])
391
+ elif self.args[0].is_imaginary:
392
+ from sympy.functions.special.delta_functions import DiracDelta
393
+ return 2 * Derivative(self.args[0], x, evaluate=True) \
394
+ * DiracDelta(-I * self.args[0])
395
+
396
+ def _eval_is_nonnegative(self):
397
+ if self.args[0].is_nonnegative:
398
+ return True
399
+
400
+ def _eval_is_nonpositive(self):
401
+ if self.args[0].is_nonpositive:
402
+ return True
403
+
404
+ def _eval_is_imaginary(self):
405
+ return self.args[0].is_imaginary
406
+
407
+ def _eval_is_integer(self):
408
+ return self.args[0].is_extended_real
409
+
410
+ def _eval_is_zero(self):
411
+ return self.args[0].is_zero
412
+
413
+ def _eval_power(self, other):
414
+ if (
415
+ fuzzy_not(self.args[0].is_zero) and
416
+ other.is_integer and
417
+ other.is_even
418
+ ):
419
+ return S.One
420
+
421
+ def _eval_nseries(self, x, n, logx, cdir=0):
422
+ arg0 = self.args[0]
423
+ x0 = arg0.subs(x, 0)
424
+ if x0 != 0:
425
+ return self.func(x0)
426
+ if cdir != 0:
427
+ cdir = arg0.dir(x, cdir)
428
+ return -S.One if re(cdir) < 0 else S.One
429
+
430
+ def _eval_rewrite_as_Piecewise(self, arg, **kwargs):
431
+ if arg.is_extended_real:
432
+ return Piecewise((1, arg > 0), (-1, arg < 0), (0, True))
433
+
434
+ def _eval_rewrite_as_Heaviside(self, arg, **kwargs):
435
+ from sympy.functions.special.delta_functions import Heaviside
436
+ if arg.is_extended_real:
437
+ return Heaviside(arg) * 2 - 1
438
+
439
+ def _eval_rewrite_as_Abs(self, arg, **kwargs):
440
+ return Piecewise((0, Eq(arg, 0)), (arg / Abs(arg), True))
441
+
442
+ def _eval_simplify(self, **kwargs):
443
+ return self.func(factor_terms(self.args[0])) # XXX include doit?
444
+
445
+
446
+ class Abs(Function):
447
+ """
448
+ Return the absolute value of the argument.
449
+
450
+ Explanation
451
+ ===========
452
+
453
+ This is an extension of the built-in function ``abs()`` to accept symbolic
454
+ values. If you pass a SymPy expression to the built-in ``abs()``, it will
455
+ pass it automatically to ``Abs()``.
456
+
457
+ Examples
458
+ ========
459
+
460
+ >>> from sympy import Abs, Symbol, S, I
461
+ >>> Abs(-1)
462
+ 1
463
+ >>> x = Symbol('x', real=True)
464
+ >>> Abs(-x)
465
+ Abs(x)
466
+ >>> Abs(x**2)
467
+ x**2
468
+ >>> abs(-x) # The Python built-in
469
+ Abs(x)
470
+ >>> Abs(3*x + 2*I)
471
+ sqrt(9*x**2 + 4)
472
+ >>> Abs(8*I)
473
+ 8
474
+
475
+ Note that the Python built-in will return either an Expr or int depending on
476
+ the argument::
477
+
478
+ >>> type(abs(-1))
479
+ <... 'int'>
480
+ >>> type(abs(S.NegativeOne))
481
+ <class 'sympy.core.numbers.One'>
482
+
483
+ Abs will always return a SymPy object.
484
+
485
+ Parameters
486
+ ==========
487
+
488
+ arg : Expr
489
+ Real or complex expression.
490
+
491
+ Returns
492
+ =======
493
+
494
+ expr : Expr
495
+ Absolute value returned can be an expression or integer depending on
496
+ input arg.
497
+
498
+ See Also
499
+ ========
500
+
501
+ sign, conjugate
502
+ """
503
+
504
+ args: tTuple[Expr]
505
+
506
+ is_extended_real = True
507
+ is_extended_negative = False
508
+ is_extended_nonnegative = True
509
+ unbranched = True
510
+ _singularities = True # non-holomorphic
511
+
512
+ def fdiff(self, argindex=1):
513
+ """
514
+ Get the first derivative of the argument to Abs().
515
+
516
+ """
517
+ if argindex == 1:
518
+ return sign(self.args[0])
519
+ else:
520
+ raise ArgumentIndexError(self, argindex)
521
+
522
+ @classmethod
523
+ def eval(cls, arg):
524
+ from sympy.simplify.simplify import signsimp
525
+
526
+ if hasattr(arg, '_eval_Abs'):
527
+ obj = arg._eval_Abs()
528
+ if obj is not None:
529
+ return obj
530
+ if not isinstance(arg, Expr):
531
+ raise TypeError("Bad argument type for Abs(): %s" % type(arg))
532
+
533
+ # handle what we can
534
+ arg = signsimp(arg, evaluate=False)
535
+ n, d = arg.as_numer_denom()
536
+ if d.free_symbols and not n.free_symbols:
537
+ return cls(n)/cls(d)
538
+
539
+ if arg.is_Mul:
540
+ known = []
541
+ unk = []
542
+ for t in arg.args:
543
+ if t.is_Pow and t.exp.is_integer and t.exp.is_negative:
544
+ bnew = cls(t.base)
545
+ if isinstance(bnew, cls):
546
+ unk.append(t)
547
+ else:
548
+ known.append(Pow(bnew, t.exp))
549
+ else:
550
+ tnew = cls(t)
551
+ if isinstance(tnew, cls):
552
+ unk.append(t)
553
+ else:
554
+ known.append(tnew)
555
+ known = Mul(*known)
556
+ unk = cls(Mul(*unk), evaluate=False) if unk else S.One
557
+ return known*unk
558
+ if arg is S.NaN:
559
+ return S.NaN
560
+ if arg is S.ComplexInfinity:
561
+ return oo
562
+ from sympy.functions.elementary.exponential import exp, log
563
+
564
+ if arg.is_Pow:
565
+ base, exponent = arg.as_base_exp()
566
+ if base.is_extended_real:
567
+ if exponent.is_integer:
568
+ if exponent.is_even:
569
+ return arg
570
+ if base is S.NegativeOne:
571
+ return S.One
572
+ return Abs(base)**exponent
573
+ if base.is_extended_nonnegative:
574
+ return base**re(exponent)
575
+ if base.is_extended_negative:
576
+ return (-base)**re(exponent)*exp(-pi*im(exponent))
577
+ return
578
+ elif not base.has(Symbol): # complex base
579
+ # express base**exponent as exp(exponent*log(base))
580
+ a, b = log(base).as_real_imag()
581
+ z = a + I*b
582
+ return exp(re(exponent*z))
583
+ if isinstance(arg, exp):
584
+ return exp(re(arg.args[0]))
585
+ if isinstance(arg, AppliedUndef):
586
+ if arg.is_positive:
587
+ return arg
588
+ elif arg.is_negative:
589
+ return -arg
590
+ return
591
+ if arg.is_Add and arg.has(oo, S.NegativeInfinity):
592
+ if any(a.is_infinite for a in arg.as_real_imag()):
593
+ return oo
594
+ if arg.is_zero:
595
+ return S.Zero
596
+ if arg.is_extended_nonnegative:
597
+ return arg
598
+ if arg.is_extended_nonpositive:
599
+ return -arg
600
+ if arg.is_imaginary:
601
+ arg2 = -I * arg
602
+ if arg2.is_extended_nonnegative:
603
+ return arg2
604
+ if arg.is_extended_real:
605
+ return
606
+ # reject result if all new conjugates are just wrappers around
607
+ # an expression that was already in the arg
608
+ conj = signsimp(arg.conjugate(), evaluate=False)
609
+ new_conj = conj.atoms(conjugate) - arg.atoms(conjugate)
610
+ if new_conj and all(arg.has(i.args[0]) for i in new_conj):
611
+ return
612
+ if arg != conj and arg != -conj:
613
+ ignore = arg.atoms(Abs)
614
+ abs_free_arg = arg.xreplace({i: Dummy(real=True) for i in ignore})
615
+ unk = [a for a in abs_free_arg.free_symbols if a.is_extended_real is None]
616
+ if not unk or not all(conj.has(conjugate(u)) for u in unk):
617
+ return sqrt(expand_mul(arg*conj))
618
+
619
+ def _eval_is_real(self):
620
+ if self.args[0].is_finite:
621
+ return True
622
+
623
+ def _eval_is_integer(self):
624
+ if self.args[0].is_extended_real:
625
+ return self.args[0].is_integer
626
+
627
+ def _eval_is_extended_nonzero(self):
628
+ return fuzzy_not(self._args[0].is_zero)
629
+
630
+ def _eval_is_zero(self):
631
+ return self._args[0].is_zero
632
+
633
+ def _eval_is_extended_positive(self):
634
+ return fuzzy_not(self._args[0].is_zero)
635
+
636
+ def _eval_is_rational(self):
637
+ if self.args[0].is_extended_real:
638
+ return self.args[0].is_rational
639
+
640
+ def _eval_is_even(self):
641
+ if self.args[0].is_extended_real:
642
+ return self.args[0].is_even
643
+
644
+ def _eval_is_odd(self):
645
+ if self.args[0].is_extended_real:
646
+ return self.args[0].is_odd
647
+
648
+ def _eval_is_algebraic(self):
649
+ return self.args[0].is_algebraic
650
+
651
+ def _eval_power(self, exponent):
652
+ if self.args[0].is_extended_real and exponent.is_integer:
653
+ if exponent.is_even:
654
+ return self.args[0]**exponent
655
+ elif exponent is not S.NegativeOne and exponent.is_Integer:
656
+ return self.args[0]**(exponent - 1)*self
657
+ return
658
+
659
+ def _eval_nseries(self, x, n, logx, cdir=0):
660
+ from sympy.functions.elementary.exponential import log
661
+ direction = self.args[0].leadterm(x)[0]
662
+ if direction.has(log(x)):
663
+ direction = direction.subs(log(x), logx)
664
+ s = self.args[0]._eval_nseries(x, n=n, logx=logx)
665
+ return (sign(direction)*s).expand()
666
+
667
+ def _eval_derivative(self, x):
668
+ if self.args[0].is_extended_real or self.args[0].is_imaginary:
669
+ return Derivative(self.args[0], x, evaluate=True) \
670
+ * sign(conjugate(self.args[0]))
671
+ rv = (re(self.args[0]) * Derivative(re(self.args[0]), x,
672
+ evaluate=True) + im(self.args[0]) * Derivative(im(self.args[0]),
673
+ x, evaluate=True)) / Abs(self.args[0])
674
+ return rv.rewrite(sign)
675
+
676
+ def _eval_rewrite_as_Heaviside(self, arg, **kwargs):
677
+ # Note this only holds for real arg (since Heaviside is not defined
678
+ # for complex arguments).
679
+ from sympy.functions.special.delta_functions import Heaviside
680
+ if arg.is_extended_real:
681
+ return arg*(Heaviside(arg) - Heaviside(-arg))
682
+
683
+ def _eval_rewrite_as_Piecewise(self, arg, **kwargs):
684
+ if arg.is_extended_real:
685
+ return Piecewise((arg, arg >= 0), (-arg, True))
686
+ elif arg.is_imaginary:
687
+ return Piecewise((I*arg, I*arg >= 0), (-I*arg, True))
688
+
689
+ def _eval_rewrite_as_sign(self, arg, **kwargs):
690
+ return arg/sign(arg)
691
+
692
+ def _eval_rewrite_as_conjugate(self, arg, **kwargs):
693
+ return sqrt(arg*conjugate(arg))
694
+
695
+
696
+ class arg(Function):
697
+ r"""
698
+ Returns the argument (in radians) of a complex number. The argument is
699
+ evaluated in consistent convention with ``atan2`` where the branch-cut is
700
+ taken along the negative real axis and ``arg(z)`` is in the interval
701
+ $(-\pi,\pi]$. For a positive number, the argument is always 0; the
702
+ argument of a negative number is $\pi$; and the argument of 0
703
+ is undefined and returns ``nan``. So the ``arg`` function will never nest
704
+ greater than 3 levels since at the 4th application, the result must be
705
+ nan; for a real number, nan is returned on the 3rd application.
706
+
707
+ Examples
708
+ ========
709
+
710
+ >>> from sympy import arg, I, sqrt, Dummy
711
+ >>> from sympy.abc import x
712
+ >>> arg(2.0)
713
+ 0
714
+ >>> arg(I)
715
+ pi/2
716
+ >>> arg(sqrt(2) + I*sqrt(2))
717
+ pi/4
718
+ >>> arg(sqrt(3)/2 + I/2)
719
+ pi/6
720
+ >>> arg(4 + 3*I)
721
+ atan(3/4)
722
+ >>> arg(0.8 + 0.6*I)
723
+ 0.643501108793284
724
+ >>> arg(arg(arg(arg(x))))
725
+ nan
726
+ >>> real = Dummy(real=True)
727
+ >>> arg(arg(arg(real)))
728
+ nan
729
+
730
+ Parameters
731
+ ==========
732
+
733
+ arg : Expr
734
+ Real or complex expression.
735
+
736
+ Returns
737
+ =======
738
+
739
+ value : Expr
740
+ Returns arc tangent of arg measured in radians.
741
+
742
+ """
743
+
744
+ is_extended_real = True
745
+ is_real = True
746
+ is_finite = True
747
+ _singularities = True # non-holomorphic
748
+
749
+ @classmethod
750
+ def eval(cls, arg):
751
+ a = arg
752
+ for i in range(3):
753
+ if isinstance(a, cls):
754
+ a = a.args[0]
755
+ else:
756
+ if i == 2 and a.is_extended_real:
757
+ return S.NaN
758
+ break
759
+ else:
760
+ return S.NaN
761
+ from sympy.functions.elementary.exponential import exp_polar
762
+ if isinstance(arg, exp_polar):
763
+ return periodic_argument(arg, oo)
764
+ if not arg.is_Atom:
765
+ c, arg_ = factor_terms(arg).as_coeff_Mul()
766
+ if arg_.is_Mul:
767
+ arg_ = Mul(*[a if (sign(a) not in (-1, 1)) else
768
+ sign(a) for a in arg_.args])
769
+ arg_ = sign(c)*arg_
770
+ else:
771
+ arg_ = arg
772
+ if any(i.is_extended_positive is None for i in arg_.atoms(AppliedUndef)):
773
+ return
774
+ from sympy.functions.elementary.trigonometric import atan2
775
+ x, y = arg_.as_real_imag()
776
+ rv = atan2(y, x)
777
+ if rv.is_number:
778
+ return rv
779
+ if arg_ != arg:
780
+ return cls(arg_, evaluate=False)
781
+
782
+ def _eval_derivative(self, t):
783
+ x, y = self.args[0].as_real_imag()
784
+ return (x * Derivative(y, t, evaluate=True) - y *
785
+ Derivative(x, t, evaluate=True)) / (x**2 + y**2)
786
+
787
+ def _eval_rewrite_as_atan2(self, arg, **kwargs):
788
+ from sympy.functions.elementary.trigonometric import atan2
789
+ x, y = self.args[0].as_real_imag()
790
+ return atan2(y, x)
791
+
792
+
793
+ class conjugate(Function):
794
+ """
795
+ Returns the *complex conjugate* [1]_ of an argument.
796
+ In mathematics, the complex conjugate of a complex number
797
+ is given by changing the sign of the imaginary part.
798
+
799
+ Thus, the conjugate of the complex number
800
+ :math:`a + ib` (where $a$ and $b$ are real numbers) is :math:`a - ib`
801
+
802
+ Examples
803
+ ========
804
+
805
+ >>> from sympy import conjugate, I
806
+ >>> conjugate(2)
807
+ 2
808
+ >>> conjugate(I)
809
+ -I
810
+ >>> conjugate(3 + 2*I)
811
+ 3 - 2*I
812
+ >>> conjugate(5 - I)
813
+ 5 + I
814
+
815
+ Parameters
816
+ ==========
817
+
818
+ arg : Expr
819
+ Real or complex expression.
820
+
821
+ Returns
822
+ =======
823
+
824
+ arg : Expr
825
+ Complex conjugate of arg as real, imaginary or mixed expression.
826
+
827
+ See Also
828
+ ========
829
+
830
+ sign, Abs
831
+
832
+ References
833
+ ==========
834
+
835
+ .. [1] https://en.wikipedia.org/wiki/Complex_conjugation
836
+ """
837
+ _singularities = True # non-holomorphic
838
+
839
+ @classmethod
840
+ def eval(cls, arg):
841
+ obj = arg._eval_conjugate()
842
+ if obj is not None:
843
+ return obj
844
+
845
+ def inverse(self):
846
+ return conjugate
847
+
848
+ def _eval_Abs(self):
849
+ return Abs(self.args[0], evaluate=True)
850
+
851
+ def _eval_adjoint(self):
852
+ return transpose(self.args[0])
853
+
854
+ def _eval_conjugate(self):
855
+ return self.args[0]
856
+
857
+ def _eval_derivative(self, x):
858
+ if x.is_real:
859
+ return conjugate(Derivative(self.args[0], x, evaluate=True))
860
+ elif x.is_imaginary:
861
+ return -conjugate(Derivative(self.args[0], x, evaluate=True))
862
+
863
+ def _eval_transpose(self):
864
+ return adjoint(self.args[0])
865
+
866
+ def _eval_is_algebraic(self):
867
+ return self.args[0].is_algebraic
868
+
869
+
870
+ class transpose(Function):
871
+ """
872
+ Linear map transposition.
873
+
874
+ Examples
875
+ ========
876
+
877
+ >>> from sympy import transpose, Matrix, MatrixSymbol
878
+ >>> A = MatrixSymbol('A', 25, 9)
879
+ >>> transpose(A)
880
+ A.T
881
+ >>> B = MatrixSymbol('B', 9, 22)
882
+ >>> transpose(B)
883
+ B.T
884
+ >>> transpose(A*B)
885
+ B.T*A.T
886
+ >>> M = Matrix([[4, 5], [2, 1], [90, 12]])
887
+ >>> M
888
+ Matrix([
889
+ [ 4, 5],
890
+ [ 2, 1],
891
+ [90, 12]])
892
+ >>> transpose(M)
893
+ Matrix([
894
+ [4, 2, 90],
895
+ [5, 1, 12]])
896
+
897
+ Parameters
898
+ ==========
899
+
900
+ arg : Matrix
901
+ Matrix or matrix expression to take the transpose of.
902
+
903
+ Returns
904
+ =======
905
+
906
+ value : Matrix
907
+ Transpose of arg.
908
+
909
+ """
910
+
911
+ @classmethod
912
+ def eval(cls, arg):
913
+ obj = arg._eval_transpose()
914
+ if obj is not None:
915
+ return obj
916
+
917
+ def _eval_adjoint(self):
918
+ return conjugate(self.args[0])
919
+
920
+ def _eval_conjugate(self):
921
+ return adjoint(self.args[0])
922
+
923
+ def _eval_transpose(self):
924
+ return self.args[0]
925
+
926
+
927
+ class adjoint(Function):
928
+ """
929
+ Conjugate transpose or Hermite conjugation.
930
+
931
+ Examples
932
+ ========
933
+
934
+ >>> from sympy import adjoint, MatrixSymbol
935
+ >>> A = MatrixSymbol('A', 10, 5)
936
+ >>> adjoint(A)
937
+ Adjoint(A)
938
+
939
+ Parameters
940
+ ==========
941
+
942
+ arg : Matrix
943
+ Matrix or matrix expression to take the adjoint of.
944
+
945
+ Returns
946
+ =======
947
+
948
+ value : Matrix
949
+ Represents the conjugate transpose or Hermite
950
+ conjugation of arg.
951
+
952
+ """
953
+
954
+ @classmethod
955
+ def eval(cls, arg):
956
+ obj = arg._eval_adjoint()
957
+ if obj is not None:
958
+ return obj
959
+ obj = arg._eval_transpose()
960
+ if obj is not None:
961
+ return conjugate(obj)
962
+
963
+ def _eval_adjoint(self):
964
+ return self.args[0]
965
+
966
+ def _eval_conjugate(self):
967
+ return transpose(self.args[0])
968
+
969
+ def _eval_transpose(self):
970
+ return conjugate(self.args[0])
971
+
972
+ def _latex(self, printer, exp=None, *args):
973
+ arg = printer._print(self.args[0])
974
+ tex = r'%s^{\dagger}' % arg
975
+ if exp:
976
+ tex = r'\left(%s\right)^{%s}' % (tex, exp)
977
+ return tex
978
+
979
+ def _pretty(self, printer, *args):
980
+ from sympy.printing.pretty.stringpict import prettyForm
981
+ pform = printer._print(self.args[0], *args)
982
+ if printer._use_unicode:
983
+ pform = pform**prettyForm('\N{DAGGER}')
984
+ else:
985
+ pform = pform**prettyForm('+')
986
+ return pform
987
+
988
+ ###############################################################################
989
+ ############### HANDLING OF POLAR NUMBERS #####################################
990
+ ###############################################################################
991
+
992
+
993
+ class polar_lift(Function):
994
+ """
995
+ Lift argument to the Riemann surface of the logarithm, using the
996
+ standard branch.
997
+
998
+ Examples
999
+ ========
1000
+
1001
+ >>> from sympy import Symbol, polar_lift, I
1002
+ >>> p = Symbol('p', polar=True)
1003
+ >>> x = Symbol('x')
1004
+ >>> polar_lift(4)
1005
+ 4*exp_polar(0)
1006
+ >>> polar_lift(-4)
1007
+ 4*exp_polar(I*pi)
1008
+ >>> polar_lift(-I)
1009
+ exp_polar(-I*pi/2)
1010
+ >>> polar_lift(I + 2)
1011
+ polar_lift(2 + I)
1012
+
1013
+ >>> polar_lift(4*x)
1014
+ 4*polar_lift(x)
1015
+ >>> polar_lift(4*p)
1016
+ 4*p
1017
+
1018
+ Parameters
1019
+ ==========
1020
+
1021
+ arg : Expr
1022
+ Real or complex expression.
1023
+
1024
+ See Also
1025
+ ========
1026
+
1027
+ sympy.functions.elementary.exponential.exp_polar
1028
+ periodic_argument
1029
+ """
1030
+
1031
+ is_polar = True
1032
+ is_comparable = False # Cannot be evalf'd.
1033
+
1034
+ @classmethod
1035
+ def eval(cls, arg):
1036
+ from sympy.functions.elementary.complexes import arg as argument
1037
+ if arg.is_number:
1038
+ ar = argument(arg)
1039
+ # In general we want to affirm that something is known,
1040
+ # e.g. `not ar.has(argument) and not ar.has(atan)`
1041
+ # but for now we will just be more restrictive and
1042
+ # see that it has evaluated to one of the known values.
1043
+ if ar in (0, pi/2, -pi/2, pi):
1044
+ from sympy.functions.elementary.exponential import exp_polar
1045
+ return exp_polar(I*ar)*abs(arg)
1046
+
1047
+ if arg.is_Mul:
1048
+ args = arg.args
1049
+ else:
1050
+ args = [arg]
1051
+ included = []
1052
+ excluded = []
1053
+ positive = []
1054
+ for arg in args:
1055
+ if arg.is_polar:
1056
+ included += [arg]
1057
+ elif arg.is_positive:
1058
+ positive += [arg]
1059
+ else:
1060
+ excluded += [arg]
1061
+ if len(excluded) < len(args):
1062
+ if excluded:
1063
+ return Mul(*(included + positive))*polar_lift(Mul(*excluded))
1064
+ elif included:
1065
+ return Mul(*(included + positive))
1066
+ else:
1067
+ from sympy.functions.elementary.exponential import exp_polar
1068
+ return Mul(*positive)*exp_polar(0)
1069
+
1070
+ def _eval_evalf(self, prec):
1071
+ """ Careful! any evalf of polar numbers is flaky """
1072
+ return self.args[0]._eval_evalf(prec)
1073
+
1074
+ def _eval_Abs(self):
1075
+ return Abs(self.args[0], evaluate=True)
1076
+
1077
+
1078
+ class periodic_argument(Function):
1079
+ r"""
1080
+ Represent the argument on a quotient of the Riemann surface of the
1081
+ logarithm. That is, given a period $P$, always return a value in
1082
+ $(-P/2, P/2]$, by using $\exp(PI) = 1$.
1083
+
1084
+ Examples
1085
+ ========
1086
+
1087
+ >>> from sympy import exp_polar, periodic_argument
1088
+ >>> from sympy import I, pi
1089
+ >>> periodic_argument(exp_polar(10*I*pi), 2*pi)
1090
+ 0
1091
+ >>> periodic_argument(exp_polar(5*I*pi), 4*pi)
1092
+ pi
1093
+ >>> from sympy import exp_polar, periodic_argument
1094
+ >>> from sympy import I, pi
1095
+ >>> periodic_argument(exp_polar(5*I*pi), 2*pi)
1096
+ pi
1097
+ >>> periodic_argument(exp_polar(5*I*pi), 3*pi)
1098
+ -pi
1099
+ >>> periodic_argument(exp_polar(5*I*pi), pi)
1100
+ 0
1101
+
1102
+ Parameters
1103
+ ==========
1104
+
1105
+ ar : Expr
1106
+ A polar number.
1107
+
1108
+ period : Expr
1109
+ The period $P$.
1110
+
1111
+ See Also
1112
+ ========
1113
+
1114
+ sympy.functions.elementary.exponential.exp_polar
1115
+ polar_lift : Lift argument to the Riemann surface of the logarithm
1116
+ principal_branch
1117
+ """
1118
+
1119
+ @classmethod
1120
+ def _getunbranched(cls, ar):
1121
+ from sympy.functions.elementary.exponential import exp_polar, log
1122
+ if ar.is_Mul:
1123
+ args = ar.args
1124
+ else:
1125
+ args = [ar]
1126
+ unbranched = 0
1127
+ for a in args:
1128
+ if not a.is_polar:
1129
+ unbranched += arg(a)
1130
+ elif isinstance(a, exp_polar):
1131
+ unbranched += a.exp.as_real_imag()[1]
1132
+ elif a.is_Pow:
1133
+ re, im = a.exp.as_real_imag()
1134
+ unbranched += re*unbranched_argument(
1135
+ a.base) + im*log(abs(a.base))
1136
+ elif isinstance(a, polar_lift):
1137
+ unbranched += arg(a.args[0])
1138
+ else:
1139
+ return None
1140
+ return unbranched
1141
+
1142
+ @classmethod
1143
+ def eval(cls, ar, period):
1144
+ # Our strategy is to evaluate the argument on the Riemann surface of the
1145
+ # logarithm, and then reduce.
1146
+ # NOTE evidently this means it is a rather bad idea to use this with
1147
+ # period != 2*pi and non-polar numbers.
1148
+ if not period.is_extended_positive:
1149
+ return None
1150
+ if period == oo and isinstance(ar, principal_branch):
1151
+ return periodic_argument(*ar.args)
1152
+ if isinstance(ar, polar_lift) and period >= 2*pi:
1153
+ return periodic_argument(ar.args[0], period)
1154
+ if ar.is_Mul:
1155
+ newargs = [x for x in ar.args if not x.is_positive]
1156
+ if len(newargs) != len(ar.args):
1157
+ return periodic_argument(Mul(*newargs), period)
1158
+ unbranched = cls._getunbranched(ar)
1159
+ if unbranched is None:
1160
+ return None
1161
+ from sympy.functions.elementary.trigonometric import atan, atan2
1162
+ if unbranched.has(periodic_argument, atan2, atan):
1163
+ return None
1164
+ if period == oo:
1165
+ return unbranched
1166
+ if period != oo:
1167
+ from sympy.functions.elementary.integers import ceiling
1168
+ n = ceiling(unbranched/period - S.Half)*period
1169
+ if not n.has(ceiling):
1170
+ return unbranched - n
1171
+
1172
+ def _eval_evalf(self, prec):
1173
+ z, period = self.args
1174
+ if period == oo:
1175
+ unbranched = periodic_argument._getunbranched(z)
1176
+ if unbranched is None:
1177
+ return self
1178
+ return unbranched._eval_evalf(prec)
1179
+ ub = periodic_argument(z, oo)._eval_evalf(prec)
1180
+ from sympy.functions.elementary.integers import ceiling
1181
+ return (ub - ceiling(ub/period - S.Half)*period)._eval_evalf(prec)
1182
+
1183
+
1184
+ def unbranched_argument(arg):
1185
+ '''
1186
+ Returns periodic argument of arg with period as infinity.
1187
+
1188
+ Examples
1189
+ ========
1190
+
1191
+ >>> from sympy import exp_polar, unbranched_argument
1192
+ >>> from sympy import I, pi
1193
+ >>> unbranched_argument(exp_polar(15*I*pi))
1194
+ 15*pi
1195
+ >>> unbranched_argument(exp_polar(7*I*pi))
1196
+ 7*pi
1197
+
1198
+ See also
1199
+ ========
1200
+
1201
+ periodic_argument
1202
+ '''
1203
+ return periodic_argument(arg, oo)
1204
+
1205
+
1206
+ class principal_branch(Function):
1207
+ """
1208
+ Represent a polar number reduced to its principal branch on a quotient
1209
+ of the Riemann surface of the logarithm.
1210
+
1211
+ Explanation
1212
+ ===========
1213
+
1214
+ This is a function of two arguments. The first argument is a polar
1215
+ number `z`, and the second one a positive real number or infinity, `p`.
1216
+ The result is ``z mod exp_polar(I*p)``.
1217
+
1218
+ Examples
1219
+ ========
1220
+
1221
+ >>> from sympy import exp_polar, principal_branch, oo, I, pi
1222
+ >>> from sympy.abc import z
1223
+ >>> principal_branch(z, oo)
1224
+ z
1225
+ >>> principal_branch(exp_polar(2*pi*I)*3, 2*pi)
1226
+ 3*exp_polar(0)
1227
+ >>> principal_branch(exp_polar(2*pi*I)*3*z, 2*pi)
1228
+ 3*principal_branch(z, 2*pi)
1229
+
1230
+ Parameters
1231
+ ==========
1232
+
1233
+ x : Expr
1234
+ A polar number.
1235
+
1236
+ period : Expr
1237
+ Positive real number or infinity.
1238
+
1239
+ See Also
1240
+ ========
1241
+
1242
+ sympy.functions.elementary.exponential.exp_polar
1243
+ polar_lift : Lift argument to the Riemann surface of the logarithm
1244
+ periodic_argument
1245
+ """
1246
+
1247
+ is_polar = True
1248
+ is_comparable = False # cannot always be evalf'd
1249
+
1250
+ @classmethod
1251
+ def eval(self, x, period):
1252
+ from sympy.functions.elementary.exponential import exp_polar
1253
+ if isinstance(x, polar_lift):
1254
+ return principal_branch(x.args[0], period)
1255
+ if period == oo:
1256
+ return x
1257
+ ub = periodic_argument(x, oo)
1258
+ barg = periodic_argument(x, period)
1259
+ if ub != barg and not ub.has(periodic_argument) \
1260
+ and not barg.has(periodic_argument):
1261
+ pl = polar_lift(x)
1262
+
1263
+ def mr(expr):
1264
+ if not isinstance(expr, Symbol):
1265
+ return polar_lift(expr)
1266
+ return expr
1267
+ pl = pl.replace(polar_lift, mr)
1268
+ # Recompute unbranched argument
1269
+ ub = periodic_argument(pl, oo)
1270
+ if not pl.has(polar_lift):
1271
+ if ub != barg:
1272
+ res = exp_polar(I*(barg - ub))*pl
1273
+ else:
1274
+ res = pl
1275
+ if not res.is_polar and not res.has(exp_polar):
1276
+ res *= exp_polar(0)
1277
+ return res
1278
+
1279
+ if not x.free_symbols:
1280
+ c, m = x, ()
1281
+ else:
1282
+ c, m = x.as_coeff_mul(*x.free_symbols)
1283
+ others = []
1284
+ for y in m:
1285
+ if y.is_positive:
1286
+ c *= y
1287
+ else:
1288
+ others += [y]
1289
+ m = tuple(others)
1290
+ arg = periodic_argument(c, period)
1291
+ if arg.has(periodic_argument):
1292
+ return None
1293
+ if arg.is_number and (unbranched_argument(c) != arg or
1294
+ (arg == 0 and m != () and c != 1)):
1295
+ if arg == 0:
1296
+ return abs(c)*principal_branch(Mul(*m), period)
1297
+ return principal_branch(exp_polar(I*arg)*Mul(*m), period)*abs(c)
1298
+ if arg.is_number and ((abs(arg) < period/2) == True or arg == period/2) \
1299
+ and m == ():
1300
+ return exp_polar(arg*I)*abs(c)
1301
+
1302
+ def _eval_evalf(self, prec):
1303
+ z, period = self.args
1304
+ p = periodic_argument(z, period)._eval_evalf(prec)
1305
+ if abs(p) > pi or p == -pi:
1306
+ return self # Cannot evalf for this argument.
1307
+ from sympy.functions.elementary.exponential import exp
1308
+ return (abs(z)*exp(I*p))._eval_evalf(prec)
1309
+
1310
+
1311
+ def _polarify(eq, lift, pause=False):
1312
+ from sympy.integrals.integrals import Integral
1313
+ if eq.is_polar:
1314
+ return eq
1315
+ if eq.is_number and not pause:
1316
+ return polar_lift(eq)
1317
+ if isinstance(eq, Symbol) and not pause and lift:
1318
+ return polar_lift(eq)
1319
+ elif eq.is_Atom:
1320
+ return eq
1321
+ elif eq.is_Add:
1322
+ r = eq.func(*[_polarify(arg, lift, pause=True) for arg in eq.args])
1323
+ if lift:
1324
+ return polar_lift(r)
1325
+ return r
1326
+ elif eq.is_Pow and eq.base == S.Exp1:
1327
+ return eq.func(S.Exp1, _polarify(eq.exp, lift, pause=False))
1328
+ elif eq.is_Function:
1329
+ return eq.func(*[_polarify(arg, lift, pause=False) for arg in eq.args])
1330
+ elif isinstance(eq, Integral):
1331
+ # Don't lift the integration variable
1332
+ func = _polarify(eq.function, lift, pause=pause)
1333
+ limits = []
1334
+ for limit in eq.args[1:]:
1335
+ var = _polarify(limit[0], lift=False, pause=pause)
1336
+ rest = _polarify(limit[1:], lift=lift, pause=pause)
1337
+ limits.append((var,) + rest)
1338
+ return Integral(*((func,) + tuple(limits)))
1339
+ else:
1340
+ return eq.func(*[_polarify(arg, lift, pause=pause)
1341
+ if isinstance(arg, Expr) else arg for arg in eq.args])
1342
+
1343
+
1344
+ def polarify(eq, subs=True, lift=False):
1345
+ """
1346
+ Turn all numbers in eq into their polar equivalents (under the standard
1347
+ choice of argument).
1348
+
1349
+ Note that no attempt is made to guess a formal convention of adding
1350
+ polar numbers, expressions like $1 + x$ will generally not be altered.
1351
+
1352
+ Note also that this function does not promote ``exp(x)`` to ``exp_polar(x)``.
1353
+
1354
+ If ``subs`` is ``True``, all symbols which are not already polar will be
1355
+ substituted for polar dummies; in this case the function behaves much
1356
+ like :func:`~.posify`.
1357
+
1358
+ If ``lift`` is ``True``, both addition statements and non-polar symbols are
1359
+ changed to their ``polar_lift()``ed versions.
1360
+ Note that ``lift=True`` implies ``subs=False``.
1361
+
1362
+ Examples
1363
+ ========
1364
+
1365
+ >>> from sympy import polarify, sin, I
1366
+ >>> from sympy.abc import x, y
1367
+ >>> expr = (-x)**y
1368
+ >>> expr.expand()
1369
+ (-x)**y
1370
+ >>> polarify(expr)
1371
+ ((_x*exp_polar(I*pi))**_y, {_x: x, _y: y})
1372
+ >>> polarify(expr)[0].expand()
1373
+ _x**_y*exp_polar(_y*I*pi)
1374
+ >>> polarify(x, lift=True)
1375
+ polar_lift(x)
1376
+ >>> polarify(x*(1+y), lift=True)
1377
+ polar_lift(x)*polar_lift(y + 1)
1378
+
1379
+ Adds are treated carefully:
1380
+
1381
+ >>> polarify(1 + sin((1 + I)*x))
1382
+ (sin(_x*polar_lift(1 + I)) + 1, {_x: x})
1383
+ """
1384
+ if lift:
1385
+ subs = False
1386
+ eq = _polarify(sympify(eq), lift)
1387
+ if not subs:
1388
+ return eq
1389
+ reps = {s: Dummy(s.name, polar=True) for s in eq.free_symbols}
1390
+ eq = eq.subs(reps)
1391
+ return eq, {r: s for s, r in reps.items()}
1392
+
1393
+
1394
+ def _unpolarify(eq, exponents_only, pause=False):
1395
+ if not isinstance(eq, Basic) or eq.is_Atom:
1396
+ return eq
1397
+
1398
+ if not pause:
1399
+ from sympy.functions.elementary.exponential import exp, exp_polar
1400
+ if isinstance(eq, exp_polar):
1401
+ return exp(_unpolarify(eq.exp, exponents_only))
1402
+ if isinstance(eq, principal_branch) and eq.args[1] == 2*pi:
1403
+ return _unpolarify(eq.args[0], exponents_only)
1404
+ if (
1405
+ eq.is_Add or eq.is_Mul or eq.is_Boolean or
1406
+ eq.is_Relational and (
1407
+ eq.rel_op in ('==', '!=') and 0 in eq.args or
1408
+ eq.rel_op not in ('==', '!='))
1409
+ ):
1410
+ return eq.func(*[_unpolarify(x, exponents_only) for x in eq.args])
1411
+ if isinstance(eq, polar_lift):
1412
+ return _unpolarify(eq.args[0], exponents_only)
1413
+
1414
+ if eq.is_Pow:
1415
+ expo = _unpolarify(eq.exp, exponents_only)
1416
+ base = _unpolarify(eq.base, exponents_only,
1417
+ not (expo.is_integer and not pause))
1418
+ return base**expo
1419
+
1420
+ if eq.is_Function and getattr(eq.func, 'unbranched', False):
1421
+ return eq.func(*[_unpolarify(x, exponents_only, exponents_only)
1422
+ for x in eq.args])
1423
+
1424
+ return eq.func(*[_unpolarify(x, exponents_only, True) for x in eq.args])
1425
+
1426
+
1427
+ def unpolarify(eq, subs=None, exponents_only=False):
1428
+ """
1429
+ If `p` denotes the projection from the Riemann surface of the logarithm to
1430
+ the complex line, return a simplified version `eq'` of `eq` such that
1431
+ `p(eq') = p(eq)`.
1432
+ Also apply the substitution subs in the end. (This is a convenience, since
1433
+ ``unpolarify``, in a certain sense, undoes :func:`polarify`.)
1434
+
1435
+ Examples
1436
+ ========
1437
+
1438
+ >>> from sympy import unpolarify, polar_lift, sin, I
1439
+ >>> unpolarify(polar_lift(I + 2))
1440
+ 2 + I
1441
+ >>> unpolarify(sin(polar_lift(I + 7)))
1442
+ sin(7 + I)
1443
+ """
1444
+ if isinstance(eq, bool):
1445
+ return eq
1446
+
1447
+ eq = sympify(eq)
1448
+ if subs is not None:
1449
+ return unpolarify(eq.subs(subs))
1450
+ changed = True
1451
+ pause = False
1452
+ if exponents_only:
1453
+ pause = True
1454
+ while changed:
1455
+ changed = False
1456
+ res = _unpolarify(eq, exponents_only, pause)
1457
+ if res != eq:
1458
+ changed = True
1459
+ eq = res
1460
+ if isinstance(res, bool):
1461
+ return res
1462
+ # Finally, replacing Exp(0) by 1 is always correct.
1463
+ # So is polar_lift(0) -> 0.
1464
+ from sympy.functions.elementary.exponential import exp_polar
1465
+ return res.subs({exp_polar(0): 1, polar_lift(0): 0})
venv/lib/python3.10/site-packages/sympy/functions/elementary/exponential.py ADDED
@@ -0,0 +1,1291 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ from itertools import product
2
+ from typing import Tuple as tTuple
3
+
4
+ from sympy.core.add import Add
5
+ from sympy.core.cache import cacheit
6
+ from sympy.core.expr import Expr
7
+ from sympy.core.function import (Function, ArgumentIndexError, expand_log,
8
+ expand_mul, FunctionClass, PoleError, expand_multinomial, expand_complex)
9
+ from sympy.core.logic import fuzzy_and, fuzzy_not, fuzzy_or
10
+ from sympy.core.mul import Mul
11
+ from sympy.core.numbers import Integer, Rational, pi, I, ImaginaryUnit
12
+ from sympy.core.parameters import global_parameters
13
+ from sympy.core.power import Pow
14
+ from sympy.core.singleton import S
15
+ from sympy.core.symbol import Wild, Dummy
16
+ from sympy.core.sympify import sympify
17
+ from sympy.functions.combinatorial.factorials import factorial
18
+ from sympy.functions.elementary.complexes import arg, unpolarify, im, re, Abs
19
+ from sympy.functions.elementary.miscellaneous import sqrt
20
+ from sympy.ntheory import multiplicity, perfect_power
21
+ from sympy.ntheory.factor_ import factorint
22
+
23
+ # NOTE IMPORTANT
24
+ # The series expansion code in this file is an important part of the gruntz
25
+ # algorithm for determining limits. _eval_nseries has to return a generalized
26
+ # power series with coefficients in C(log(x), log).
27
+ # In more detail, the result of _eval_nseries(self, x, n) must be
28
+ # c_0*x**e_0 + ... (finitely many terms)
29
+ # where e_i are numbers (not necessarily integers) and c_i involve only
30
+ # numbers, the function log, and log(x). [This also means it must not contain
31
+ # log(x(1+p)), this *has* to be expanded to log(x)+log(1+p) if x.is_positive and
32
+ # p.is_positive.]
33
+
34
+
35
+ class ExpBase(Function):
36
+
37
+ unbranched = True
38
+ _singularities = (S.ComplexInfinity,)
39
+
40
+ @property
41
+ def kind(self):
42
+ return self.exp.kind
43
+
44
+ def inverse(self, argindex=1):
45
+ """
46
+ Returns the inverse function of ``exp(x)``.
47
+ """
48
+ return log
49
+
50
+ def as_numer_denom(self):
51
+ """
52
+ Returns this with a positive exponent as a 2-tuple (a fraction).
53
+
54
+ Examples
55
+ ========
56
+
57
+ >>> from sympy import exp
58
+ >>> from sympy.abc import x
59
+ >>> exp(-x).as_numer_denom()
60
+ (1, exp(x))
61
+ >>> exp(x).as_numer_denom()
62
+ (exp(x), 1)
63
+ """
64
+ # this should be the same as Pow.as_numer_denom wrt
65
+ # exponent handling
66
+ exp = self.exp
67
+ neg_exp = exp.is_negative
68
+ if not neg_exp and not (-exp).is_negative:
69
+ neg_exp = exp.could_extract_minus_sign()
70
+ if neg_exp:
71
+ return S.One, self.func(-exp)
72
+ return self, S.One
73
+
74
+ @property
75
+ def exp(self):
76
+ """
77
+ Returns the exponent of the function.
78
+ """
79
+ return self.args[0]
80
+
81
+ def as_base_exp(self):
82
+ """
83
+ Returns the 2-tuple (base, exponent).
84
+ """
85
+ return self.func(1), Mul(*self.args)
86
+
87
+ def _eval_adjoint(self):
88
+ return self.func(self.exp.adjoint())
89
+
90
+ def _eval_conjugate(self):
91
+ return self.func(self.exp.conjugate())
92
+
93
+ def _eval_transpose(self):
94
+ return self.func(self.exp.transpose())
95
+
96
+ def _eval_is_finite(self):
97
+ arg = self.exp
98
+ if arg.is_infinite:
99
+ if arg.is_extended_negative:
100
+ return True
101
+ if arg.is_extended_positive:
102
+ return False
103
+ if arg.is_finite:
104
+ return True
105
+
106
+ def _eval_is_rational(self):
107
+ s = self.func(*self.args)
108
+ if s.func == self.func:
109
+ z = s.exp.is_zero
110
+ if z:
111
+ return True
112
+ elif s.exp.is_rational and fuzzy_not(z):
113
+ return False
114
+ else:
115
+ return s.is_rational
116
+
117
+ def _eval_is_zero(self):
118
+ return self.exp is S.NegativeInfinity
119
+
120
+ def _eval_power(self, other):
121
+ """exp(arg)**e -> exp(arg*e) if assumptions allow it.
122
+ """
123
+ b, e = self.as_base_exp()
124
+ return Pow._eval_power(Pow(b, e, evaluate=False), other)
125
+
126
+ def _eval_expand_power_exp(self, **hints):
127
+ from sympy.concrete.products import Product
128
+ from sympy.concrete.summations import Sum
129
+ arg = self.args[0]
130
+ if arg.is_Add and arg.is_commutative:
131
+ return Mul.fromiter(self.func(x) for x in arg.args)
132
+ elif isinstance(arg, Sum) and arg.is_commutative:
133
+ return Product(self.func(arg.function), *arg.limits)
134
+ return self.func(arg)
135
+
136
+
137
+ class exp_polar(ExpBase):
138
+ r"""
139
+ Represent a *polar number* (see g-function Sphinx documentation).
140
+
141
+ Explanation
142
+ ===========
143
+
144
+ ``exp_polar`` represents the function
145
+ `Exp: \mathbb{C} \rightarrow \mathcal{S}`, sending the complex number
146
+ `z = a + bi` to the polar number `r = exp(a), \theta = b`. It is one of
147
+ the main functions to construct polar numbers.
148
+
149
+ Examples
150
+ ========
151
+
152
+ >>> from sympy import exp_polar, pi, I, exp
153
+
154
+ The main difference is that polar numbers do not "wrap around" at `2 \pi`:
155
+
156
+ >>> exp(2*pi*I)
157
+ 1
158
+ >>> exp_polar(2*pi*I)
159
+ exp_polar(2*I*pi)
160
+
161
+ apart from that they behave mostly like classical complex numbers:
162
+
163
+ >>> exp_polar(2)*exp_polar(3)
164
+ exp_polar(5)
165
+
166
+ See Also
167
+ ========
168
+
169
+ sympy.simplify.powsimp.powsimp
170
+ polar_lift
171
+ periodic_argument
172
+ principal_branch
173
+ """
174
+
175
+ is_polar = True
176
+ is_comparable = False # cannot be evalf'd
177
+
178
+ def _eval_Abs(self): # Abs is never a polar number
179
+ return exp(re(self.args[0]))
180
+
181
+ def _eval_evalf(self, prec):
182
+ """ Careful! any evalf of polar numbers is flaky """
183
+ i = im(self.args[0])
184
+ try:
185
+ bad = (i <= -pi or i > pi)
186
+ except TypeError:
187
+ bad = True
188
+ if bad:
189
+ return self # cannot evalf for this argument
190
+ res = exp(self.args[0])._eval_evalf(prec)
191
+ if i > 0 and im(res) < 0:
192
+ # i ~ pi, but exp(I*i) evaluated to argument slightly bigger than pi
193
+ return re(res)
194
+ return res
195
+
196
+ def _eval_power(self, other):
197
+ return self.func(self.args[0]*other)
198
+
199
+ def _eval_is_extended_real(self):
200
+ if self.args[0].is_extended_real:
201
+ return True
202
+
203
+ def as_base_exp(self):
204
+ # XXX exp_polar(0) is special!
205
+ if self.args[0] == 0:
206
+ return self, S.One
207
+ return ExpBase.as_base_exp(self)
208
+
209
+
210
+ class ExpMeta(FunctionClass):
211
+ def __instancecheck__(cls, instance):
212
+ if exp in instance.__class__.__mro__:
213
+ return True
214
+ return isinstance(instance, Pow) and instance.base is S.Exp1
215
+
216
+
217
+ class exp(ExpBase, metaclass=ExpMeta):
218
+ """
219
+ The exponential function, :math:`e^x`.
220
+
221
+ Examples
222
+ ========
223
+
224
+ >>> from sympy import exp, I, pi
225
+ >>> from sympy.abc import x
226
+ >>> exp(x)
227
+ exp(x)
228
+ >>> exp(x).diff(x)
229
+ exp(x)
230
+ >>> exp(I*pi)
231
+ -1
232
+
233
+ Parameters
234
+ ==========
235
+
236
+ arg : Expr
237
+
238
+ See Also
239
+ ========
240
+
241
+ log
242
+ """
243
+
244
+ def fdiff(self, argindex=1):
245
+ """
246
+ Returns the first derivative of this function.
247
+ """
248
+ if argindex == 1:
249
+ return self
250
+ else:
251
+ raise ArgumentIndexError(self, argindex)
252
+
253
+ def _eval_refine(self, assumptions):
254
+ from sympy.assumptions import ask, Q
255
+ arg = self.args[0]
256
+ if arg.is_Mul:
257
+ Ioo = I*S.Infinity
258
+ if arg in [Ioo, -Ioo]:
259
+ return S.NaN
260
+
261
+ coeff = arg.as_coefficient(pi*I)
262
+ if coeff:
263
+ if ask(Q.integer(2*coeff)):
264
+ if ask(Q.even(coeff)):
265
+ return S.One
266
+ elif ask(Q.odd(coeff)):
267
+ return S.NegativeOne
268
+ elif ask(Q.even(coeff + S.Half)):
269
+ return -I
270
+ elif ask(Q.odd(coeff + S.Half)):
271
+ return I
272
+
273
+ @classmethod
274
+ def eval(cls, arg):
275
+ from sympy.calculus import AccumBounds
276
+ from sympy.matrices.matrices import MatrixBase
277
+ from sympy.sets.setexpr import SetExpr
278
+ from sympy.simplify.simplify import logcombine
279
+ if isinstance(arg, MatrixBase):
280
+ return arg.exp()
281
+ elif global_parameters.exp_is_pow:
282
+ return Pow(S.Exp1, arg)
283
+ elif arg.is_Number:
284
+ if arg is S.NaN:
285
+ return S.NaN
286
+ elif arg.is_zero:
287
+ return S.One
288
+ elif arg is S.One:
289
+ return S.Exp1
290
+ elif arg is S.Infinity:
291
+ return S.Infinity
292
+ elif arg is S.NegativeInfinity:
293
+ return S.Zero
294
+ elif arg is S.ComplexInfinity:
295
+ return S.NaN
296
+ elif isinstance(arg, log):
297
+ return arg.args[0]
298
+ elif isinstance(arg, AccumBounds):
299
+ return AccumBounds(exp(arg.min), exp(arg.max))
300
+ elif isinstance(arg, SetExpr):
301
+ return arg._eval_func(cls)
302
+ elif arg.is_Mul:
303
+ coeff = arg.as_coefficient(pi*I)
304
+ if coeff:
305
+ if (2*coeff).is_integer:
306
+ if coeff.is_even:
307
+ return S.One
308
+ elif coeff.is_odd:
309
+ return S.NegativeOne
310
+ elif (coeff + S.Half).is_even:
311
+ return -I
312
+ elif (coeff + S.Half).is_odd:
313
+ return I
314
+ elif coeff.is_Rational:
315
+ ncoeff = coeff % 2 # restrict to [0, 2pi)
316
+ if ncoeff > 1: # restrict to (-pi, pi]
317
+ ncoeff -= 2
318
+ if ncoeff != coeff:
319
+ return cls(ncoeff*pi*I)
320
+
321
+ # Warning: code in risch.py will be very sensitive to changes
322
+ # in this (see DifferentialExtension).
323
+
324
+ # look for a single log factor
325
+
326
+ coeff, terms = arg.as_coeff_Mul()
327
+
328
+ # but it can't be multiplied by oo
329
+ if coeff in [S.NegativeInfinity, S.Infinity]:
330
+ if terms.is_number:
331
+ if coeff is S.NegativeInfinity:
332
+ terms = -terms
333
+ if re(terms).is_zero and terms is not S.Zero:
334
+ return S.NaN
335
+ if re(terms).is_positive and im(terms) is not S.Zero:
336
+ return S.ComplexInfinity
337
+ if re(terms).is_negative:
338
+ return S.Zero
339
+ return None
340
+
341
+ coeffs, log_term = [coeff], None
342
+ for term in Mul.make_args(terms):
343
+ term_ = logcombine(term)
344
+ if isinstance(term_, log):
345
+ if log_term is None:
346
+ log_term = term_.args[0]
347
+ else:
348
+ return None
349
+ elif term.is_comparable:
350
+ coeffs.append(term)
351
+ else:
352
+ return None
353
+
354
+ return log_term**Mul(*coeffs) if log_term else None
355
+
356
+ elif arg.is_Add:
357
+ out = []
358
+ add = []
359
+ argchanged = False
360
+ for a in arg.args:
361
+ if a is S.One:
362
+ add.append(a)
363
+ continue
364
+ newa = cls(a)
365
+ if isinstance(newa, cls):
366
+ if newa.args[0] != a:
367
+ add.append(newa.args[0])
368
+ argchanged = True
369
+ else:
370
+ add.append(a)
371
+ else:
372
+ out.append(newa)
373
+ if out or argchanged:
374
+ return Mul(*out)*cls(Add(*add), evaluate=False)
375
+
376
+ if arg.is_zero:
377
+ return S.One
378
+
379
+ @property
380
+ def base(self):
381
+ """
382
+ Returns the base of the exponential function.
383
+ """
384
+ return S.Exp1
385
+
386
+ @staticmethod
387
+ @cacheit
388
+ def taylor_term(n, x, *previous_terms):
389
+ """
390
+ Calculates the next term in the Taylor series expansion.
391
+ """
392
+ if n < 0:
393
+ return S.Zero
394
+ if n == 0:
395
+ return S.One
396
+ x = sympify(x)
397
+ if previous_terms:
398
+ p = previous_terms[-1]
399
+ if p is not None:
400
+ return p * x / n
401
+ return x**n/factorial(n)
402
+
403
+ def as_real_imag(self, deep=True, **hints):
404
+ """
405
+ Returns this function as a 2-tuple representing a complex number.
406
+
407
+ Examples
408
+ ========
409
+
410
+ >>> from sympy import exp, I
411
+ >>> from sympy.abc import x
412
+ >>> exp(x).as_real_imag()
413
+ (exp(re(x))*cos(im(x)), exp(re(x))*sin(im(x)))
414
+ >>> exp(1).as_real_imag()
415
+ (E, 0)
416
+ >>> exp(I).as_real_imag()
417
+ (cos(1), sin(1))
418
+ >>> exp(1+I).as_real_imag()
419
+ (E*cos(1), E*sin(1))
420
+
421
+ See Also
422
+ ========
423
+
424
+ sympy.functions.elementary.complexes.re
425
+ sympy.functions.elementary.complexes.im
426
+ """
427
+ from sympy.functions.elementary.trigonometric import cos, sin
428
+ re, im = self.args[0].as_real_imag()
429
+ if deep:
430
+ re = re.expand(deep, **hints)
431
+ im = im.expand(deep, **hints)
432
+ cos, sin = cos(im), sin(im)
433
+ return (exp(re)*cos, exp(re)*sin)
434
+
435
+ def _eval_subs(self, old, new):
436
+ # keep processing of power-like args centralized in Pow
437
+ if old.is_Pow: # handle (exp(3*log(x))).subs(x**2, z) -> z**(3/2)
438
+ old = exp(old.exp*log(old.base))
439
+ elif old is S.Exp1 and new.is_Function:
440
+ old = exp
441
+ if isinstance(old, exp) or old is S.Exp1:
442
+ f = lambda a: Pow(*a.as_base_exp(), evaluate=False) if (
443
+ a.is_Pow or isinstance(a, exp)) else a
444
+ return Pow._eval_subs(f(self), f(old), new)
445
+
446
+ if old is exp and not new.is_Function:
447
+ return new**self.exp._subs(old, new)
448
+ return Function._eval_subs(self, old, new)
449
+
450
+ def _eval_is_extended_real(self):
451
+ if self.args[0].is_extended_real:
452
+ return True
453
+ elif self.args[0].is_imaginary:
454
+ arg2 = -S(2) * I * self.args[0] / pi
455
+ return arg2.is_even
456
+
457
+ def _eval_is_complex(self):
458
+ def complex_extended_negative(arg):
459
+ yield arg.is_complex
460
+ yield arg.is_extended_negative
461
+ return fuzzy_or(complex_extended_negative(self.args[0]))
462
+
463
+ def _eval_is_algebraic(self):
464
+ if (self.exp / pi / I).is_rational:
465
+ return True
466
+ if fuzzy_not(self.exp.is_zero):
467
+ if self.exp.is_algebraic:
468
+ return False
469
+ elif (self.exp / pi).is_rational:
470
+ return False
471
+
472
+ def _eval_is_extended_positive(self):
473
+ if self.exp.is_extended_real:
474
+ return self.args[0] is not S.NegativeInfinity
475
+ elif self.exp.is_imaginary:
476
+ arg2 = -I * self.args[0] / pi
477
+ return arg2.is_even
478
+
479
+ def _eval_nseries(self, x, n, logx, cdir=0):
480
+ # NOTE Please see the comment at the beginning of this file, labelled
481
+ # IMPORTANT.
482
+ from sympy.functions.elementary.complexes import sign
483
+ from sympy.functions.elementary.integers import ceiling
484
+ from sympy.series.limits import limit
485
+ from sympy.series.order import Order
486
+ from sympy.simplify.powsimp import powsimp
487
+ arg = self.exp
488
+ arg_series = arg._eval_nseries(x, n=n, logx=logx)
489
+ if arg_series.is_Order:
490
+ return 1 + arg_series
491
+ arg0 = limit(arg_series.removeO(), x, 0)
492
+ if arg0 is S.NegativeInfinity:
493
+ return Order(x**n, x)
494
+ if arg0 is S.Infinity:
495
+ return self
496
+ # checking for indecisiveness/ sign terms in arg0
497
+ if any(isinstance(arg, (sign, ImaginaryUnit)) for arg in arg0.args):
498
+ return self
499
+ t = Dummy("t")
500
+ nterms = n
501
+ try:
502
+ cf = Order(arg.as_leading_term(x, logx=logx), x).getn()
503
+ except (NotImplementedError, PoleError):
504
+ cf = 0
505
+ if cf and cf > 0:
506
+ nterms = ceiling(n/cf)
507
+ exp_series = exp(t)._taylor(t, nterms)
508
+ r = exp(arg0)*exp_series.subs(t, arg_series - arg0)
509
+ rep = {logx: log(x)} if logx is not None else {}
510
+ if r.subs(rep) == self:
511
+ return r
512
+ if cf and cf > 1:
513
+ r += Order((arg_series - arg0)**n, x)/x**((cf-1)*n)
514
+ else:
515
+ r += Order((arg_series - arg0)**n, x)
516
+ r = r.expand()
517
+ r = powsimp(r, deep=True, combine='exp')
518
+ # powsimp may introduce unexpanded (-1)**Rational; see PR #17201
519
+ simplerat = lambda x: x.is_Rational and x.q in [3, 4, 6]
520
+ w = Wild('w', properties=[simplerat])
521
+ r = r.replace(S.NegativeOne**w, expand_complex(S.NegativeOne**w))
522
+ return r
523
+
524
+ def _taylor(self, x, n):
525
+ l = []
526
+ g = None
527
+ for i in range(n):
528
+ g = self.taylor_term(i, self.args[0], g)
529
+ g = g.nseries(x, n=n)
530
+ l.append(g.removeO())
531
+ return Add(*l)
532
+
533
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
534
+ from sympy.calculus.util import AccumBounds
535
+ arg = self.args[0].cancel().as_leading_term(x, logx=logx)
536
+ arg0 = arg.subs(x, 0)
537
+ if arg is S.NaN:
538
+ return S.NaN
539
+ if isinstance(arg0, AccumBounds):
540
+ # This check addresses a corner case involving AccumBounds.
541
+ # if isinstance(arg, AccumBounds) is True, then arg0 can either be 0,
542
+ # AccumBounds(-oo, 0) or AccumBounds(-oo, oo).
543
+ # Check out function: test_issue_18473() in test_exponential.py and
544
+ # test_limits.py for more information.
545
+ if re(cdir) < S.Zero:
546
+ return exp(-arg0)
547
+ return exp(arg0)
548
+ if arg0 is S.NaN:
549
+ arg0 = arg.limit(x, 0)
550
+ if arg0.is_infinite is False:
551
+ return exp(arg0)
552
+ raise PoleError("Cannot expand %s around 0" % (self))
553
+
554
+ def _eval_rewrite_as_sin(self, arg, **kwargs):
555
+ from sympy.functions.elementary.trigonometric import sin
556
+ return sin(I*arg + pi/2) - I*sin(I*arg)
557
+
558
+ def _eval_rewrite_as_cos(self, arg, **kwargs):
559
+ from sympy.functions.elementary.trigonometric import cos
560
+ return cos(I*arg) + I*cos(I*arg + pi/2)
561
+
562
+ def _eval_rewrite_as_tanh(self, arg, **kwargs):
563
+ from sympy.functions.elementary.hyperbolic import tanh
564
+ return (1 + tanh(arg/2))/(1 - tanh(arg/2))
565
+
566
+ def _eval_rewrite_as_sqrt(self, arg, **kwargs):
567
+ from sympy.functions.elementary.trigonometric import sin, cos
568
+ if arg.is_Mul:
569
+ coeff = arg.coeff(pi*I)
570
+ if coeff and coeff.is_number:
571
+ cosine, sine = cos(pi*coeff), sin(pi*coeff)
572
+ if not isinstance(cosine, cos) and not isinstance (sine, sin):
573
+ return cosine + I*sine
574
+
575
+ def _eval_rewrite_as_Pow(self, arg, **kwargs):
576
+ if arg.is_Mul:
577
+ logs = [a for a in arg.args if isinstance(a, log) and len(a.args) == 1]
578
+ if logs:
579
+ return Pow(logs[0].args[0], arg.coeff(logs[0]))
580
+
581
+
582
+ def match_real_imag(expr):
583
+ r"""
584
+ Try to match expr with $a + Ib$ for real $a$ and $b$.
585
+
586
+ ``match_real_imag`` returns a tuple containing the real and imaginary
587
+ parts of expr or ``(None, None)`` if direct matching is not possible. Contrary
588
+ to :func:`~.re()`, :func:`~.im()``, and ``as_real_imag()``, this helper will not force things
589
+ by returning expressions themselves containing ``re()`` or ``im()`` and it
590
+ does not expand its argument either.
591
+
592
+ """
593
+ r_, i_ = expr.as_independent(I, as_Add=True)
594
+ if i_ == 0 and r_.is_real:
595
+ return (r_, i_)
596
+ i_ = i_.as_coefficient(I)
597
+ if i_ and i_.is_real and r_.is_real:
598
+ return (r_, i_)
599
+ else:
600
+ return (None, None) # simpler to check for than None
601
+
602
+
603
+ class log(Function):
604
+ r"""
605
+ The natural logarithm function `\ln(x)` or `\log(x)`.
606
+
607
+ Explanation
608
+ ===========
609
+
610
+ Logarithms are taken with the natural base, `e`. To get
611
+ a logarithm of a different base ``b``, use ``log(x, b)``,
612
+ which is essentially short-hand for ``log(x)/log(b)``.
613
+
614
+ ``log`` represents the principal branch of the natural
615
+ logarithm. As such it has a branch cut along the negative
616
+ real axis and returns values having a complex argument in
617
+ `(-\pi, \pi]`.
618
+
619
+ Examples
620
+ ========
621
+
622
+ >>> from sympy import log, sqrt, S, I
623
+ >>> log(8, 2)
624
+ 3
625
+ >>> log(S(8)/3, 2)
626
+ -log(3)/log(2) + 3
627
+ >>> log(-1 + I*sqrt(3))
628
+ log(2) + 2*I*pi/3
629
+
630
+ See Also
631
+ ========
632
+
633
+ exp
634
+
635
+ """
636
+
637
+ args: tTuple[Expr]
638
+
639
+ _singularities = (S.Zero, S.ComplexInfinity)
640
+
641
+ def fdiff(self, argindex=1):
642
+ """
643
+ Returns the first derivative of the function.
644
+ """
645
+ if argindex == 1:
646
+ return 1/self.args[0]
647
+ else:
648
+ raise ArgumentIndexError(self, argindex)
649
+
650
+ def inverse(self, argindex=1):
651
+ r"""
652
+ Returns `e^x`, the inverse function of `\log(x)`.
653
+ """
654
+ return exp
655
+
656
+ @classmethod
657
+ def eval(cls, arg, base=None):
658
+ from sympy.calculus import AccumBounds
659
+ from sympy.sets.setexpr import SetExpr
660
+
661
+ arg = sympify(arg)
662
+
663
+ if base is not None:
664
+ base = sympify(base)
665
+ if base == 1:
666
+ if arg == 1:
667
+ return S.NaN
668
+ else:
669
+ return S.ComplexInfinity
670
+ try:
671
+ # handle extraction of powers of the base now
672
+ # or else expand_log in Mul would have to handle this
673
+ n = multiplicity(base, arg)
674
+ if n:
675
+ return n + log(arg / base**n) / log(base)
676
+ else:
677
+ return log(arg)/log(base)
678
+ except ValueError:
679
+ pass
680
+ if base is not S.Exp1:
681
+ return cls(arg)/cls(base)
682
+ else:
683
+ return cls(arg)
684
+
685
+ if arg.is_Number:
686
+ if arg.is_zero:
687
+ return S.ComplexInfinity
688
+ elif arg is S.One:
689
+ return S.Zero
690
+ elif arg is S.Infinity:
691
+ return S.Infinity
692
+ elif arg is S.NegativeInfinity:
693
+ return S.Infinity
694
+ elif arg is S.NaN:
695
+ return S.NaN
696
+ elif arg.is_Rational and arg.p == 1:
697
+ return -cls(arg.q)
698
+
699
+ if arg.is_Pow and arg.base is S.Exp1 and arg.exp.is_extended_real:
700
+ return arg.exp
701
+ if isinstance(arg, exp) and arg.exp.is_extended_real:
702
+ return arg.exp
703
+ elif isinstance(arg, exp) and arg.exp.is_number:
704
+ r_, i_ = match_real_imag(arg.exp)
705
+ if i_ and i_.is_comparable:
706
+ i_ %= 2*pi
707
+ if i_ > pi:
708
+ i_ -= 2*pi
709
+ return r_ + expand_mul(i_ * I, deep=False)
710
+ elif isinstance(arg, exp_polar):
711
+ return unpolarify(arg.exp)
712
+ elif isinstance(arg, AccumBounds):
713
+ if arg.min.is_positive:
714
+ return AccumBounds(log(arg.min), log(arg.max))
715
+ elif arg.min.is_zero:
716
+ return AccumBounds(S.NegativeInfinity, log(arg.max))
717
+ else:
718
+ return S.NaN
719
+ elif isinstance(arg, SetExpr):
720
+ return arg._eval_func(cls)
721
+
722
+ if arg.is_number:
723
+ if arg.is_negative:
724
+ return pi * I + cls(-arg)
725
+ elif arg is S.ComplexInfinity:
726
+ return S.ComplexInfinity
727
+ elif arg is S.Exp1:
728
+ return S.One
729
+
730
+ if arg.is_zero:
731
+ return S.ComplexInfinity
732
+
733
+ # don't autoexpand Pow or Mul (see the issue 3351):
734
+ if not arg.is_Add:
735
+ coeff = arg.as_coefficient(I)
736
+
737
+ if coeff is not None:
738
+ if coeff is S.Infinity:
739
+ return S.Infinity
740
+ elif coeff is S.NegativeInfinity:
741
+ return S.Infinity
742
+ elif coeff.is_Rational:
743
+ if coeff.is_nonnegative:
744
+ return pi * I * S.Half + cls(coeff)
745
+ else:
746
+ return -pi * I * S.Half + cls(-coeff)
747
+
748
+ if arg.is_number and arg.is_algebraic:
749
+ # Match arg = coeff*(r_ + i_*I) with coeff>0, r_ and i_ real.
750
+ coeff, arg_ = arg.as_independent(I, as_Add=False)
751
+ if coeff.is_negative:
752
+ coeff *= -1
753
+ arg_ *= -1
754
+ arg_ = expand_mul(arg_, deep=False)
755
+ r_, i_ = arg_.as_independent(I, as_Add=True)
756
+ i_ = i_.as_coefficient(I)
757
+ if coeff.is_real and i_ and i_.is_real and r_.is_real:
758
+ if r_.is_zero:
759
+ if i_.is_positive:
760
+ return pi * I * S.Half + cls(coeff * i_)
761
+ elif i_.is_negative:
762
+ return -pi * I * S.Half + cls(coeff * -i_)
763
+ else:
764
+ from sympy.simplify import ratsimp
765
+ # Check for arguments involving rational multiples of pi
766
+ t = (i_/r_).cancel()
767
+ t1 = (-t).cancel()
768
+ atan_table = _log_atan_table()
769
+ if t in atan_table:
770
+ modulus = ratsimp(coeff * Abs(arg_))
771
+ if r_.is_positive:
772
+ return cls(modulus) + I * atan_table[t]
773
+ else:
774
+ return cls(modulus) + I * (atan_table[t] - pi)
775
+ elif t1 in atan_table:
776
+ modulus = ratsimp(coeff * Abs(arg_))
777
+ if r_.is_positive:
778
+ return cls(modulus) + I * (-atan_table[t1])
779
+ else:
780
+ return cls(modulus) + I * (pi - atan_table[t1])
781
+
782
+ def as_base_exp(self):
783
+ """
784
+ Returns this function in the form (base, exponent).
785
+ """
786
+ return self, S.One
787
+
788
+ @staticmethod
789
+ @cacheit
790
+ def taylor_term(n, x, *previous_terms): # of log(1+x)
791
+ r"""
792
+ Returns the next term in the Taylor series expansion of `\log(1+x)`.
793
+ """
794
+ from sympy.simplify.powsimp import powsimp
795
+ if n < 0:
796
+ return S.Zero
797
+ x = sympify(x)
798
+ if n == 0:
799
+ return x
800
+ if previous_terms:
801
+ p = previous_terms[-1]
802
+ if p is not None:
803
+ return powsimp((-n) * p * x / (n + 1), deep=True, combine='exp')
804
+ return (1 - 2*(n % 2)) * x**(n + 1)/(n + 1)
805
+
806
+ def _eval_expand_log(self, deep=True, **hints):
807
+ from sympy.concrete import Sum, Product
808
+ force = hints.get('force', False)
809
+ factor = hints.get('factor', False)
810
+ if (len(self.args) == 2):
811
+ return expand_log(self.func(*self.args), deep=deep, force=force)
812
+ arg = self.args[0]
813
+ if arg.is_Integer:
814
+ # remove perfect powers
815
+ p = perfect_power(arg)
816
+ logarg = None
817
+ coeff = 1
818
+ if p is not False:
819
+ arg, coeff = p
820
+ logarg = self.func(arg)
821
+ # expand as product of its prime factors if factor=True
822
+ if factor:
823
+ p = factorint(arg)
824
+ if arg not in p.keys():
825
+ logarg = sum(n*log(val) for val, n in p.items())
826
+ if logarg is not None:
827
+ return coeff*logarg
828
+ elif arg.is_Rational:
829
+ return log(arg.p) - log(arg.q)
830
+ elif arg.is_Mul:
831
+ expr = []
832
+ nonpos = []
833
+ for x in arg.args:
834
+ if force or x.is_positive or x.is_polar:
835
+ a = self.func(x)
836
+ if isinstance(a, log):
837
+ expr.append(self.func(x)._eval_expand_log(**hints))
838
+ else:
839
+ expr.append(a)
840
+ elif x.is_negative:
841
+ a = self.func(-x)
842
+ expr.append(a)
843
+ nonpos.append(S.NegativeOne)
844
+ else:
845
+ nonpos.append(x)
846
+ return Add(*expr) + log(Mul(*nonpos))
847
+ elif arg.is_Pow or isinstance(arg, exp):
848
+ if force or (arg.exp.is_extended_real and (arg.base.is_positive or ((arg.exp+1)
849
+ .is_positive and (arg.exp-1).is_nonpositive))) or arg.base.is_polar:
850
+ b = arg.base
851
+ e = arg.exp
852
+ a = self.func(b)
853
+ if isinstance(a, log):
854
+ return unpolarify(e) * a._eval_expand_log(**hints)
855
+ else:
856
+ return unpolarify(e) * a
857
+ elif isinstance(arg, Product):
858
+ if force or arg.function.is_positive:
859
+ return Sum(log(arg.function), *arg.limits)
860
+
861
+ return self.func(arg)
862
+
863
+ def _eval_simplify(self, **kwargs):
864
+ from sympy.simplify.simplify import expand_log, simplify, inversecombine
865
+ if len(self.args) == 2: # it's unevaluated
866
+ return simplify(self.func(*self.args), **kwargs)
867
+
868
+ expr = self.func(simplify(self.args[0], **kwargs))
869
+ if kwargs['inverse']:
870
+ expr = inversecombine(expr)
871
+ expr = expand_log(expr, deep=True)
872
+ return min([expr, self], key=kwargs['measure'])
873
+
874
+ def as_real_imag(self, deep=True, **hints):
875
+ """
876
+ Returns this function as a complex coordinate.
877
+
878
+ Examples
879
+ ========
880
+
881
+ >>> from sympy import I, log
882
+ >>> from sympy.abc import x
883
+ >>> log(x).as_real_imag()
884
+ (log(Abs(x)), arg(x))
885
+ >>> log(I).as_real_imag()
886
+ (0, pi/2)
887
+ >>> log(1 + I).as_real_imag()
888
+ (log(sqrt(2)), pi/4)
889
+ >>> log(I*x).as_real_imag()
890
+ (log(Abs(x)), arg(I*x))
891
+
892
+ """
893
+ sarg = self.args[0]
894
+ if deep:
895
+ sarg = self.args[0].expand(deep, **hints)
896
+ sarg_abs = Abs(sarg)
897
+ if sarg_abs == sarg:
898
+ return self, S.Zero
899
+ sarg_arg = arg(sarg)
900
+ if hints.get('log', False): # Expand the log
901
+ hints['complex'] = False
902
+ return (log(sarg_abs).expand(deep, **hints), sarg_arg)
903
+ else:
904
+ return log(sarg_abs), sarg_arg
905
+
906
+ def _eval_is_rational(self):
907
+ s = self.func(*self.args)
908
+ if s.func == self.func:
909
+ if (self.args[0] - 1).is_zero:
910
+ return True
911
+ if s.args[0].is_rational and fuzzy_not((self.args[0] - 1).is_zero):
912
+ return False
913
+ else:
914
+ return s.is_rational
915
+
916
+ def _eval_is_algebraic(self):
917
+ s = self.func(*self.args)
918
+ if s.func == self.func:
919
+ if (self.args[0] - 1).is_zero:
920
+ return True
921
+ elif fuzzy_not((self.args[0] - 1).is_zero):
922
+ if self.args[0].is_algebraic:
923
+ return False
924
+ else:
925
+ return s.is_algebraic
926
+
927
+ def _eval_is_extended_real(self):
928
+ return self.args[0].is_extended_positive
929
+
930
+ def _eval_is_complex(self):
931
+ z = self.args[0]
932
+ return fuzzy_and([z.is_complex, fuzzy_not(z.is_zero)])
933
+
934
+ def _eval_is_finite(self):
935
+ arg = self.args[0]
936
+ if arg.is_zero:
937
+ return False
938
+ return arg.is_finite
939
+
940
+ def _eval_is_extended_positive(self):
941
+ return (self.args[0] - 1).is_extended_positive
942
+
943
+ def _eval_is_zero(self):
944
+ return (self.args[0] - 1).is_zero
945
+
946
+ def _eval_is_extended_nonnegative(self):
947
+ return (self.args[0] - 1).is_extended_nonnegative
948
+
949
+ def _eval_nseries(self, x, n, logx, cdir=0):
950
+ # NOTE Please see the comment at the beginning of this file, labelled
951
+ # IMPORTANT.
952
+ from sympy.series.order import Order
953
+ from sympy.simplify.simplify import logcombine
954
+ from sympy.core.symbol import Dummy
955
+
956
+ if self.args[0] == x:
957
+ return log(x) if logx is None else logx
958
+ arg = self.args[0]
959
+ t = Dummy('t', positive=True)
960
+ if cdir == 0:
961
+ cdir = 1
962
+ z = arg.subs(x, cdir*t)
963
+
964
+ k, l = Wild("k"), Wild("l")
965
+ r = z.match(k*t**l)
966
+ if r is not None:
967
+ k, l = r[k], r[l]
968
+ if l != 0 and not l.has(t) and not k.has(t):
969
+ r = l*log(x) if logx is None else l*logx
970
+ r += log(k) - l*log(cdir) # XXX true regardless of assumptions?
971
+ return r
972
+
973
+ def coeff_exp(term, x):
974
+ coeff, exp = S.One, S.Zero
975
+ for factor in Mul.make_args(term):
976
+ if factor.has(x):
977
+ base, exp = factor.as_base_exp()
978
+ if base != x:
979
+ try:
980
+ return term.leadterm(x)
981
+ except ValueError:
982
+ return term, S.Zero
983
+ else:
984
+ coeff *= factor
985
+ return coeff, exp
986
+
987
+ # TODO new and probably slow
988
+ try:
989
+ a, b = z.leadterm(t, logx=logx, cdir=1)
990
+ except (ValueError, NotImplementedError, PoleError):
991
+ s = z._eval_nseries(t, n=n, logx=logx, cdir=1)
992
+ while s.is_Order:
993
+ n += 1
994
+ s = z._eval_nseries(t, n=n, logx=logx, cdir=1)
995
+ try:
996
+ a, b = s.removeO().leadterm(t, cdir=1)
997
+ except ValueError:
998
+ a, b = s.removeO().as_leading_term(t, cdir=1), S.Zero
999
+
1000
+ p = (z/(a*t**b) - 1)._eval_nseries(t, n=n, logx=logx, cdir=1)
1001
+ if p.has(exp):
1002
+ p = logcombine(p)
1003
+ if isinstance(p, Order):
1004
+ n = p.getn()
1005
+ _, d = coeff_exp(p, t)
1006
+ logx = log(x) if logx is None else logx
1007
+
1008
+ if not d.is_positive:
1009
+ res = log(a) - b*log(cdir) + b*logx
1010
+ _res = res
1011
+ logflags = {"deep": True, "log": True, "mul": False, "power_exp": False,
1012
+ "power_base": False, "multinomial": False, "basic": False, "force": True,
1013
+ "factor": False}
1014
+ expr = self.expand(**logflags)
1015
+ if (not a.could_extract_minus_sign() and
1016
+ logx.could_extract_minus_sign()):
1017
+ _res = _res.subs(-logx, -log(x)).expand(**logflags)
1018
+ else:
1019
+ _res = _res.subs(logx, log(x)).expand(**logflags)
1020
+ if _res == expr:
1021
+ return res
1022
+ return res + Order(x**n, x)
1023
+
1024
+ def mul(d1, d2):
1025
+ res = {}
1026
+ for e1, e2 in product(d1, d2):
1027
+ ex = e1 + e2
1028
+ if ex < n:
1029
+ res[ex] = res.get(ex, S.Zero) + d1[e1]*d2[e2]
1030
+ return res
1031
+
1032
+ pterms = {}
1033
+
1034
+ for term in Add.make_args(p.removeO()):
1035
+ co1, e1 = coeff_exp(term, t)
1036
+ pterms[e1] = pterms.get(e1, S.Zero) + co1
1037
+
1038
+ k = S.One
1039
+ terms = {}
1040
+ pk = pterms
1041
+
1042
+ while k*d < n:
1043
+ coeff = -S.NegativeOne**k/k
1044
+ for ex in pk:
1045
+ _ = terms.get(ex, S.Zero) + coeff*pk[ex]
1046
+ terms[ex] = _.nsimplify()
1047
+ pk = mul(pk, pterms)
1048
+ k += S.One
1049
+
1050
+ res = log(a) - b*log(cdir) + b*logx
1051
+ for ex in terms:
1052
+ res += terms[ex]*t**(ex)
1053
+
1054
+ if a.is_negative and im(z) != 0:
1055
+ from sympy.functions.special.delta_functions import Heaviside
1056
+ for i, term in enumerate(z.lseries(t)):
1057
+ if not term.is_real or i == 5:
1058
+ break
1059
+ if i < 5:
1060
+ coeff, _ = term.as_coeff_exponent(t)
1061
+ res += -2*I*pi*Heaviside(-im(coeff), 0)
1062
+
1063
+ res = res.subs(t, x/cdir)
1064
+ return res + Order(x**n, x)
1065
+
1066
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
1067
+ # NOTE
1068
+ # Refer https://github.com/sympy/sympy/pull/23592 for more information
1069
+ # on each of the following steps involved in this method.
1070
+ arg0 = self.args[0].together()
1071
+
1072
+ # STEP 1
1073
+ t = Dummy('t', positive=True)
1074
+ if cdir == 0:
1075
+ cdir = 1
1076
+ z = arg0.subs(x, cdir*t)
1077
+
1078
+ # STEP 2
1079
+ try:
1080
+ c, e = z.leadterm(t, logx=logx, cdir=1)
1081
+ except ValueError:
1082
+ arg = arg0.as_leading_term(x, logx=logx, cdir=cdir)
1083
+ return log(arg)
1084
+ if c.has(t):
1085
+ c = c.subs(t, x/cdir)
1086
+ if e != 0:
1087
+ raise PoleError("Cannot expand %s around 0" % (self))
1088
+ return log(c)
1089
+
1090
+ # STEP 3
1091
+ if c == S.One and e == S.Zero:
1092
+ return (arg0 - S.One).as_leading_term(x, logx=logx)
1093
+
1094
+ # STEP 4
1095
+ res = log(c) - e*log(cdir)
1096
+ logx = log(x) if logx is None else logx
1097
+ res += e*logx
1098
+
1099
+ # STEP 5
1100
+ if c.is_negative and im(z) != 0:
1101
+ from sympy.functions.special.delta_functions import Heaviside
1102
+ for i, term in enumerate(z.lseries(t)):
1103
+ if not term.is_real or i == 5:
1104
+ break
1105
+ if i < 5:
1106
+ coeff, _ = term.as_coeff_exponent(t)
1107
+ res += -2*I*pi*Heaviside(-im(coeff), 0)
1108
+ return res
1109
+
1110
+
1111
+ class LambertW(Function):
1112
+ r"""
1113
+ The Lambert W function $W(z)$ is defined as the inverse
1114
+ function of $w \exp(w)$ [1]_.
1115
+
1116
+ Explanation
1117
+ ===========
1118
+
1119
+ In other words, the value of $W(z)$ is such that $z = W(z) \exp(W(z))$
1120
+ for any complex number $z$. The Lambert W function is a multivalued
1121
+ function with infinitely many branches $W_k(z)$, indexed by
1122
+ $k \in \mathbb{Z}$. Each branch gives a different solution $w$
1123
+ of the equation $z = w \exp(w)$.
1124
+
1125
+ The Lambert W function has two partially real branches: the
1126
+ principal branch ($k = 0$) is real for real $z > -1/e$, and the
1127
+ $k = -1$ branch is real for $-1/e < z < 0$. All branches except
1128
+ $k = 0$ have a logarithmic singularity at $z = 0$.
1129
+
1130
+ Examples
1131
+ ========
1132
+
1133
+ >>> from sympy import LambertW
1134
+ >>> LambertW(1.2)
1135
+ 0.635564016364870
1136
+ >>> LambertW(1.2, -1).n()
1137
+ -1.34747534407696 - 4.41624341514535*I
1138
+ >>> LambertW(-1).is_real
1139
+ False
1140
+
1141
+ References
1142
+ ==========
1143
+
1144
+ .. [1] https://en.wikipedia.org/wiki/Lambert_W_function
1145
+ """
1146
+ _singularities = (-Pow(S.Exp1, -1, evaluate=False), S.ComplexInfinity)
1147
+
1148
+ @classmethod
1149
+ def eval(cls, x, k=None):
1150
+ if k == S.Zero:
1151
+ return cls(x)
1152
+ elif k is None:
1153
+ k = S.Zero
1154
+
1155
+ if k.is_zero:
1156
+ if x.is_zero:
1157
+ return S.Zero
1158
+ if x is S.Exp1:
1159
+ return S.One
1160
+ if x == -1/S.Exp1:
1161
+ return S.NegativeOne
1162
+ if x == -log(2)/2:
1163
+ return -log(2)
1164
+ if x == 2*log(2):
1165
+ return log(2)
1166
+ if x == -pi/2:
1167
+ return I*pi/2
1168
+ if x == exp(1 + S.Exp1):
1169
+ return S.Exp1
1170
+ if x is S.Infinity:
1171
+ return S.Infinity
1172
+ if x.is_zero:
1173
+ return S.Zero
1174
+
1175
+ if fuzzy_not(k.is_zero):
1176
+ if x.is_zero:
1177
+ return S.NegativeInfinity
1178
+ if k is S.NegativeOne:
1179
+ if x == -pi/2:
1180
+ return -I*pi/2
1181
+ elif x == -1/S.Exp1:
1182
+ return S.NegativeOne
1183
+ elif x == -2*exp(-2):
1184
+ return -Integer(2)
1185
+
1186
+ def fdiff(self, argindex=1):
1187
+ """
1188
+ Return the first derivative of this function.
1189
+ """
1190
+ x = self.args[0]
1191
+
1192
+ if len(self.args) == 1:
1193
+ if argindex == 1:
1194
+ return LambertW(x)/(x*(1 + LambertW(x)))
1195
+ else:
1196
+ k = self.args[1]
1197
+ if argindex == 1:
1198
+ return LambertW(x, k)/(x*(1 + LambertW(x, k)))
1199
+
1200
+ raise ArgumentIndexError(self, argindex)
1201
+
1202
+ def _eval_is_extended_real(self):
1203
+ x = self.args[0]
1204
+ if len(self.args) == 1:
1205
+ k = S.Zero
1206
+ else:
1207
+ k = self.args[1]
1208
+ if k.is_zero:
1209
+ if (x + 1/S.Exp1).is_positive:
1210
+ return True
1211
+ elif (x + 1/S.Exp1).is_nonpositive:
1212
+ return False
1213
+ elif (k + 1).is_zero:
1214
+ if x.is_negative and (x + 1/S.Exp1).is_positive:
1215
+ return True
1216
+ elif x.is_nonpositive or (x + 1/S.Exp1).is_nonnegative:
1217
+ return False
1218
+ elif fuzzy_not(k.is_zero) and fuzzy_not((k + 1).is_zero):
1219
+ if x.is_extended_real:
1220
+ return False
1221
+
1222
+ def _eval_is_finite(self):
1223
+ return self.args[0].is_finite
1224
+
1225
+ def _eval_is_algebraic(self):
1226
+ s = self.func(*self.args)
1227
+ if s.func == self.func:
1228
+ if fuzzy_not(self.args[0].is_zero) and self.args[0].is_algebraic:
1229
+ return False
1230
+ else:
1231
+ return s.is_algebraic
1232
+
1233
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
1234
+ if len(self.args) == 1:
1235
+ arg = self.args[0]
1236
+ arg0 = arg.subs(x, 0).cancel()
1237
+ if not arg0.is_zero:
1238
+ return self.func(arg0)
1239
+ return arg.as_leading_term(x)
1240
+
1241
+ def _eval_nseries(self, x, n, logx, cdir=0):
1242
+ if len(self.args) == 1:
1243
+ from sympy.functions.elementary.integers import ceiling
1244
+ from sympy.series.order import Order
1245
+ arg = self.args[0].nseries(x, n=n, logx=logx)
1246
+ lt = arg.as_leading_term(x, logx=logx)
1247
+ lte = 1
1248
+ if lt.is_Pow:
1249
+ lte = lt.exp
1250
+ if ceiling(n/lte) >= 1:
1251
+ s = Add(*[(-S.One)**(k - 1)*Integer(k)**(k - 2)/
1252
+ factorial(k - 1)*arg**k for k in range(1, ceiling(n/lte))])
1253
+ s = expand_multinomial(s)
1254
+ else:
1255
+ s = S.Zero
1256
+
1257
+ return s + Order(x**n, x)
1258
+ return super()._eval_nseries(x, n, logx)
1259
+
1260
+ def _eval_is_zero(self):
1261
+ x = self.args[0]
1262
+ if len(self.args) == 1:
1263
+ return x.is_zero
1264
+ else:
1265
+ return fuzzy_and([x.is_zero, self.args[1].is_zero])
1266
+
1267
+
1268
+ @cacheit
1269
+ def _log_atan_table():
1270
+ return {
1271
+ # first quadrant only
1272
+ sqrt(3): pi / 3,
1273
+ 1: pi / 4,
1274
+ sqrt(5 - 2 * sqrt(5)): pi / 5,
1275
+ sqrt(2) * sqrt(5 - sqrt(5)) / (1 + sqrt(5)): pi / 5,
1276
+ sqrt(5 + 2 * sqrt(5)): pi * Rational(2, 5),
1277
+ sqrt(2) * sqrt(sqrt(5) + 5) / (-1 + sqrt(5)): pi * Rational(2, 5),
1278
+ sqrt(3) / 3: pi / 6,
1279
+ sqrt(2) - 1: pi / 8,
1280
+ sqrt(2 - sqrt(2)) / sqrt(sqrt(2) + 2): pi / 8,
1281
+ sqrt(2) + 1: pi * Rational(3, 8),
1282
+ sqrt(sqrt(2) + 2) / sqrt(2 - sqrt(2)): pi * Rational(3, 8),
1283
+ sqrt(1 - 2 * sqrt(5) / 5): pi / 10,
1284
+ (-sqrt(2) + sqrt(10)) / (2 * sqrt(sqrt(5) + 5)): pi / 10,
1285
+ sqrt(1 + 2 * sqrt(5) / 5): pi * Rational(3, 10),
1286
+ (sqrt(2) + sqrt(10)) / (2 * sqrt(5 - sqrt(5))): pi * Rational(3, 10),
1287
+ 2 - sqrt(3): pi / 12,
1288
+ (-1 + sqrt(3)) / (1 + sqrt(3)): pi / 12,
1289
+ 2 + sqrt(3): pi * Rational(5, 12),
1290
+ (1 + sqrt(3)) / (-1 + sqrt(3)): pi * Rational(5, 12)
1291
+ }
venv/lib/python3.10/site-packages/sympy/functions/elementary/hyperbolic.py ADDED
@@ -0,0 +1,2203 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ from sympy.core import S, sympify, cacheit
2
+ from sympy.core.add import Add
3
+ from sympy.core.function import Function, ArgumentIndexError
4
+ from sympy.core.logic import fuzzy_or, fuzzy_and, FuzzyBool
5
+ from sympy.core.numbers import I, pi, Rational
6
+ from sympy.core.symbol import Dummy
7
+ from sympy.functions.combinatorial.factorials import (binomial, factorial,
8
+ RisingFactorial)
9
+ from sympy.functions.combinatorial.numbers import bernoulli, euler, nC
10
+ from sympy.functions.elementary.complexes import Abs, im, re
11
+ from sympy.functions.elementary.exponential import exp, log, match_real_imag
12
+ from sympy.functions.elementary.integers import floor
13
+ from sympy.functions.elementary.miscellaneous import sqrt
14
+ from sympy.functions.elementary.trigonometric import (
15
+ acos, acot, asin, atan, cos, cot, csc, sec, sin, tan,
16
+ _imaginary_unit_as_coefficient)
17
+ from sympy.polys.specialpolys import symmetric_poly
18
+
19
+
20
+ def _rewrite_hyperbolics_as_exp(expr):
21
+ return expr.xreplace({h: h.rewrite(exp)
22
+ for h in expr.atoms(HyperbolicFunction)})
23
+
24
+
25
+ @cacheit
26
+ def _acosh_table():
27
+ return {
28
+ I: log(I*(1 + sqrt(2))),
29
+ -I: log(-I*(1 + sqrt(2))),
30
+ S.Half: pi/3,
31
+ Rational(-1, 2): pi*Rational(2, 3),
32
+ sqrt(2)/2: pi/4,
33
+ -sqrt(2)/2: pi*Rational(3, 4),
34
+ 1/sqrt(2): pi/4,
35
+ -1/sqrt(2): pi*Rational(3, 4),
36
+ sqrt(3)/2: pi/6,
37
+ -sqrt(3)/2: pi*Rational(5, 6),
38
+ (sqrt(3) - 1)/sqrt(2**3): pi*Rational(5, 12),
39
+ -(sqrt(3) - 1)/sqrt(2**3): pi*Rational(7, 12),
40
+ sqrt(2 + sqrt(2))/2: pi/8,
41
+ -sqrt(2 + sqrt(2))/2: pi*Rational(7, 8),
42
+ sqrt(2 - sqrt(2))/2: pi*Rational(3, 8),
43
+ -sqrt(2 - sqrt(2))/2: pi*Rational(5, 8),
44
+ (1 + sqrt(3))/(2*sqrt(2)): pi/12,
45
+ -(1 + sqrt(3))/(2*sqrt(2)): pi*Rational(11, 12),
46
+ (sqrt(5) + 1)/4: pi/5,
47
+ -(sqrt(5) + 1)/4: pi*Rational(4, 5)
48
+ }
49
+
50
+
51
+ @cacheit
52
+ def _acsch_table():
53
+ return {
54
+ I: -pi / 2,
55
+ I*(sqrt(2) + sqrt(6)): -pi / 12,
56
+ I*(1 + sqrt(5)): -pi / 10,
57
+ I*2 / sqrt(2 - sqrt(2)): -pi / 8,
58
+ I*2: -pi / 6,
59
+ I*sqrt(2 + 2/sqrt(5)): -pi / 5,
60
+ I*sqrt(2): -pi / 4,
61
+ I*(sqrt(5)-1): -3*pi / 10,
62
+ I*2 / sqrt(3): -pi / 3,
63
+ I*2 / sqrt(2 + sqrt(2)): -3*pi / 8,
64
+ I*sqrt(2 - 2/sqrt(5)): -2*pi / 5,
65
+ I*(sqrt(6) - sqrt(2)): -5*pi / 12,
66
+ S(2): -I*log((1+sqrt(5))/2),
67
+ }
68
+
69
+
70
+ @cacheit
71
+ def _asech_table():
72
+ return {
73
+ I: - (pi*I / 2) + log(1 + sqrt(2)),
74
+ -I: (pi*I / 2) + log(1 + sqrt(2)),
75
+ (sqrt(6) - sqrt(2)): pi / 12,
76
+ (sqrt(2) - sqrt(6)): 11*pi / 12,
77
+ sqrt(2 - 2/sqrt(5)): pi / 10,
78
+ -sqrt(2 - 2/sqrt(5)): 9*pi / 10,
79
+ 2 / sqrt(2 + sqrt(2)): pi / 8,
80
+ -2 / sqrt(2 + sqrt(2)): 7*pi / 8,
81
+ 2 / sqrt(3): pi / 6,
82
+ -2 / sqrt(3): 5*pi / 6,
83
+ (sqrt(5) - 1): pi / 5,
84
+ (1 - sqrt(5)): 4*pi / 5,
85
+ sqrt(2): pi / 4,
86
+ -sqrt(2): 3*pi / 4,
87
+ sqrt(2 + 2/sqrt(5)): 3*pi / 10,
88
+ -sqrt(2 + 2/sqrt(5)): 7*pi / 10,
89
+ S(2): pi / 3,
90
+ -S(2): 2*pi / 3,
91
+ sqrt(2*(2 + sqrt(2))): 3*pi / 8,
92
+ -sqrt(2*(2 + sqrt(2))): 5*pi / 8,
93
+ (1 + sqrt(5)): 2*pi / 5,
94
+ (-1 - sqrt(5)): 3*pi / 5,
95
+ (sqrt(6) + sqrt(2)): 5*pi / 12,
96
+ (-sqrt(6) - sqrt(2)): 7*pi / 12,
97
+ I*S.Infinity: -pi*I / 2,
98
+ I*S.NegativeInfinity: pi*I / 2,
99
+ }
100
+
101
+ ###############################################################################
102
+ ########################### HYPERBOLIC FUNCTIONS ##############################
103
+ ###############################################################################
104
+
105
+
106
+ class HyperbolicFunction(Function):
107
+ """
108
+ Base class for hyperbolic functions.
109
+
110
+ See Also
111
+ ========
112
+
113
+ sinh, cosh, tanh, coth
114
+ """
115
+
116
+ unbranched = True
117
+
118
+
119
+ def _peeloff_ipi(arg):
120
+ r"""
121
+ Split ARG into two parts, a "rest" and a multiple of $I\pi$.
122
+ This assumes ARG to be an ``Add``.
123
+ The multiple of $I\pi$ returned in the second position is always a ``Rational``.
124
+
125
+ Examples
126
+ ========
127
+
128
+ >>> from sympy.functions.elementary.hyperbolic import _peeloff_ipi as peel
129
+ >>> from sympy import pi, I
130
+ >>> from sympy.abc import x, y
131
+ >>> peel(x + I*pi/2)
132
+ (x, 1/2)
133
+ >>> peel(x + I*2*pi/3 + I*pi*y)
134
+ (x + I*pi*y + I*pi/6, 1/2)
135
+ """
136
+ ipi = pi*I
137
+ for a in Add.make_args(arg):
138
+ if a == ipi:
139
+ K = S.One
140
+ break
141
+ elif a.is_Mul:
142
+ K, p = a.as_two_terms()
143
+ if p == ipi and K.is_Rational:
144
+ break
145
+ else:
146
+ return arg, S.Zero
147
+
148
+ m1 = (K % S.Half)
149
+ m2 = K - m1
150
+ return arg - m2*ipi, m2
151
+
152
+
153
+ class sinh(HyperbolicFunction):
154
+ r"""
155
+ ``sinh(x)`` is the hyperbolic sine of ``x``.
156
+
157
+ The hyperbolic sine function is $\frac{e^x - e^{-x}}{2}$.
158
+
159
+ Examples
160
+ ========
161
+
162
+ >>> from sympy import sinh
163
+ >>> from sympy.abc import x
164
+ >>> sinh(x)
165
+ sinh(x)
166
+
167
+ See Also
168
+ ========
169
+
170
+ cosh, tanh, asinh
171
+ """
172
+
173
+ def fdiff(self, argindex=1):
174
+ """
175
+ Returns the first derivative of this function.
176
+ """
177
+ if argindex == 1:
178
+ return cosh(self.args[0])
179
+ else:
180
+ raise ArgumentIndexError(self, argindex)
181
+
182
+ def inverse(self, argindex=1):
183
+ """
184
+ Returns the inverse of this function.
185
+ """
186
+ return asinh
187
+
188
+ @classmethod
189
+ def eval(cls, arg):
190
+ if arg.is_Number:
191
+ if arg is S.NaN:
192
+ return S.NaN
193
+ elif arg is S.Infinity:
194
+ return S.Infinity
195
+ elif arg is S.NegativeInfinity:
196
+ return S.NegativeInfinity
197
+ elif arg.is_zero:
198
+ return S.Zero
199
+ elif arg.is_negative:
200
+ return -cls(-arg)
201
+ else:
202
+ if arg is S.ComplexInfinity:
203
+ return S.NaN
204
+
205
+ i_coeff = _imaginary_unit_as_coefficient(arg)
206
+
207
+ if i_coeff is not None:
208
+ return I * sin(i_coeff)
209
+ else:
210
+ if arg.could_extract_minus_sign():
211
+ return -cls(-arg)
212
+
213
+ if arg.is_Add:
214
+ x, m = _peeloff_ipi(arg)
215
+ if m:
216
+ m = m*pi*I
217
+ return sinh(m)*cosh(x) + cosh(m)*sinh(x)
218
+
219
+ if arg.is_zero:
220
+ return S.Zero
221
+
222
+ if arg.func == asinh:
223
+ return arg.args[0]
224
+
225
+ if arg.func == acosh:
226
+ x = arg.args[0]
227
+ return sqrt(x - 1) * sqrt(x + 1)
228
+
229
+ if arg.func == atanh:
230
+ x = arg.args[0]
231
+ return x/sqrt(1 - x**2)
232
+
233
+ if arg.func == acoth:
234
+ x = arg.args[0]
235
+ return 1/(sqrt(x - 1) * sqrt(x + 1))
236
+
237
+ @staticmethod
238
+ @cacheit
239
+ def taylor_term(n, x, *previous_terms):
240
+ """
241
+ Returns the next term in the Taylor series expansion.
242
+ """
243
+ if n < 0 or n % 2 == 0:
244
+ return S.Zero
245
+ else:
246
+ x = sympify(x)
247
+
248
+ if len(previous_terms) > 2:
249
+ p = previous_terms[-2]
250
+ return p * x**2 / (n*(n - 1))
251
+ else:
252
+ return x**(n) / factorial(n)
253
+
254
+ def _eval_conjugate(self):
255
+ return self.func(self.args[0].conjugate())
256
+
257
+ def as_real_imag(self, deep=True, **hints):
258
+ """
259
+ Returns this function as a complex coordinate.
260
+ """
261
+ if self.args[0].is_extended_real:
262
+ if deep:
263
+ hints['complex'] = False
264
+ return (self.expand(deep, **hints), S.Zero)
265
+ else:
266
+ return (self, S.Zero)
267
+ if deep:
268
+ re, im = self.args[0].expand(deep, **hints).as_real_imag()
269
+ else:
270
+ re, im = self.args[0].as_real_imag()
271
+ return (sinh(re)*cos(im), cosh(re)*sin(im))
272
+
273
+ def _eval_expand_complex(self, deep=True, **hints):
274
+ re_part, im_part = self.as_real_imag(deep=deep, **hints)
275
+ return re_part + im_part*I
276
+
277
+ def _eval_expand_trig(self, deep=True, **hints):
278
+ if deep:
279
+ arg = self.args[0].expand(deep, **hints)
280
+ else:
281
+ arg = self.args[0]
282
+ x = None
283
+ if arg.is_Add: # TODO, implement more if deep stuff here
284
+ x, y = arg.as_two_terms()
285
+ else:
286
+ coeff, terms = arg.as_coeff_Mul(rational=True)
287
+ if coeff is not S.One and coeff.is_Integer and terms is not S.One:
288
+ x = terms
289
+ y = (coeff - 1)*x
290
+ if x is not None:
291
+ return (sinh(x)*cosh(y) + sinh(y)*cosh(x)).expand(trig=True)
292
+ return sinh(arg)
293
+
294
+ def _eval_rewrite_as_tractable(self, arg, limitvar=None, **kwargs):
295
+ return (exp(arg) - exp(-arg)) / 2
296
+
297
+ def _eval_rewrite_as_exp(self, arg, **kwargs):
298
+ return (exp(arg) - exp(-arg)) / 2
299
+
300
+ def _eval_rewrite_as_sin(self, arg, **kwargs):
301
+ return -I * sin(I * arg)
302
+
303
+ def _eval_rewrite_as_csc(self, arg, **kwargs):
304
+ return -I / csc(I * arg)
305
+
306
+ def _eval_rewrite_as_cosh(self, arg, **kwargs):
307
+ return -I*cosh(arg + pi*I/2)
308
+
309
+ def _eval_rewrite_as_tanh(self, arg, **kwargs):
310
+ tanh_half = tanh(S.Half*arg)
311
+ return 2*tanh_half/(1 - tanh_half**2)
312
+
313
+ def _eval_rewrite_as_coth(self, arg, **kwargs):
314
+ coth_half = coth(S.Half*arg)
315
+ return 2*coth_half/(coth_half**2 - 1)
316
+
317
+ def _eval_rewrite_as_csch(self, arg, **kwargs):
318
+ return 1 / csch(arg)
319
+
320
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
321
+ arg = self.args[0].as_leading_term(x, logx=logx, cdir=cdir)
322
+ arg0 = arg.subs(x, 0)
323
+
324
+ if arg0 is S.NaN:
325
+ arg0 = arg.limit(x, 0, dir='-' if cdir.is_negative else '+')
326
+ if arg0.is_zero:
327
+ return arg
328
+ elif arg0.is_finite:
329
+ return self.func(arg0)
330
+ else:
331
+ return self
332
+
333
+ def _eval_is_real(self):
334
+ arg = self.args[0]
335
+ if arg.is_real:
336
+ return True
337
+
338
+ # if `im` is of the form n*pi
339
+ # else, check if it is a number
340
+ re, im = arg.as_real_imag()
341
+ return (im%pi).is_zero
342
+
343
+ def _eval_is_extended_real(self):
344
+ if self.args[0].is_extended_real:
345
+ return True
346
+
347
+ def _eval_is_positive(self):
348
+ if self.args[0].is_extended_real:
349
+ return self.args[0].is_positive
350
+
351
+ def _eval_is_negative(self):
352
+ if self.args[0].is_extended_real:
353
+ return self.args[0].is_negative
354
+
355
+ def _eval_is_finite(self):
356
+ arg = self.args[0]
357
+ return arg.is_finite
358
+
359
+ def _eval_is_zero(self):
360
+ rest, ipi_mult = _peeloff_ipi(self.args[0])
361
+ if rest.is_zero:
362
+ return ipi_mult.is_integer
363
+
364
+
365
+ class cosh(HyperbolicFunction):
366
+ r"""
367
+ ``cosh(x)`` is the hyperbolic cosine of ``x``.
368
+
369
+ The hyperbolic cosine function is $\frac{e^x + e^{-x}}{2}$.
370
+
371
+ Examples
372
+ ========
373
+
374
+ >>> from sympy import cosh
375
+ >>> from sympy.abc import x
376
+ >>> cosh(x)
377
+ cosh(x)
378
+
379
+ See Also
380
+ ========
381
+
382
+ sinh, tanh, acosh
383
+ """
384
+
385
+ def fdiff(self, argindex=1):
386
+ if argindex == 1:
387
+ return sinh(self.args[0])
388
+ else:
389
+ raise ArgumentIndexError(self, argindex)
390
+
391
+ @classmethod
392
+ def eval(cls, arg):
393
+ from sympy.functions.elementary.trigonometric import cos
394
+ if arg.is_Number:
395
+ if arg is S.NaN:
396
+ return S.NaN
397
+ elif arg is S.Infinity:
398
+ return S.Infinity
399
+ elif arg is S.NegativeInfinity:
400
+ return S.Infinity
401
+ elif arg.is_zero:
402
+ return S.One
403
+ elif arg.is_negative:
404
+ return cls(-arg)
405
+ else:
406
+ if arg is S.ComplexInfinity:
407
+ return S.NaN
408
+
409
+ i_coeff = _imaginary_unit_as_coefficient(arg)
410
+
411
+ if i_coeff is not None:
412
+ return cos(i_coeff)
413
+ else:
414
+ if arg.could_extract_minus_sign():
415
+ return cls(-arg)
416
+
417
+ if arg.is_Add:
418
+ x, m = _peeloff_ipi(arg)
419
+ if m:
420
+ m = m*pi*I
421
+ return cosh(m)*cosh(x) + sinh(m)*sinh(x)
422
+
423
+ if arg.is_zero:
424
+ return S.One
425
+
426
+ if arg.func == asinh:
427
+ return sqrt(1 + arg.args[0]**2)
428
+
429
+ if arg.func == acosh:
430
+ return arg.args[0]
431
+
432
+ if arg.func == atanh:
433
+ return 1/sqrt(1 - arg.args[0]**2)
434
+
435
+ if arg.func == acoth:
436
+ x = arg.args[0]
437
+ return x/(sqrt(x - 1) * sqrt(x + 1))
438
+
439
+ @staticmethod
440
+ @cacheit
441
+ def taylor_term(n, x, *previous_terms):
442
+ if n < 0 or n % 2 == 1:
443
+ return S.Zero
444
+ else:
445
+ x = sympify(x)
446
+
447
+ if len(previous_terms) > 2:
448
+ p = previous_terms[-2]
449
+ return p * x**2 / (n*(n - 1))
450
+ else:
451
+ return x**(n)/factorial(n)
452
+
453
+ def _eval_conjugate(self):
454
+ return self.func(self.args[0].conjugate())
455
+
456
+ def as_real_imag(self, deep=True, **hints):
457
+ if self.args[0].is_extended_real:
458
+ if deep:
459
+ hints['complex'] = False
460
+ return (self.expand(deep, **hints), S.Zero)
461
+ else:
462
+ return (self, S.Zero)
463
+ if deep:
464
+ re, im = self.args[0].expand(deep, **hints).as_real_imag()
465
+ else:
466
+ re, im = self.args[0].as_real_imag()
467
+
468
+ return (cosh(re)*cos(im), sinh(re)*sin(im))
469
+
470
+ def _eval_expand_complex(self, deep=True, **hints):
471
+ re_part, im_part = self.as_real_imag(deep=deep, **hints)
472
+ return re_part + im_part*I
473
+
474
+ def _eval_expand_trig(self, deep=True, **hints):
475
+ if deep:
476
+ arg = self.args[0].expand(deep, **hints)
477
+ else:
478
+ arg = self.args[0]
479
+ x = None
480
+ if arg.is_Add: # TODO, implement more if deep stuff here
481
+ x, y = arg.as_two_terms()
482
+ else:
483
+ coeff, terms = arg.as_coeff_Mul(rational=True)
484
+ if coeff is not S.One and coeff.is_Integer and terms is not S.One:
485
+ x = terms
486
+ y = (coeff - 1)*x
487
+ if x is not None:
488
+ return (cosh(x)*cosh(y) + sinh(x)*sinh(y)).expand(trig=True)
489
+ return cosh(arg)
490
+
491
+ def _eval_rewrite_as_tractable(self, arg, limitvar=None, **kwargs):
492
+ return (exp(arg) + exp(-arg)) / 2
493
+
494
+ def _eval_rewrite_as_exp(self, arg, **kwargs):
495
+ return (exp(arg) + exp(-arg)) / 2
496
+
497
+ def _eval_rewrite_as_cos(self, arg, **kwargs):
498
+ return cos(I * arg)
499
+
500
+ def _eval_rewrite_as_sec(self, arg, **kwargs):
501
+ return 1 / sec(I * arg)
502
+
503
+ def _eval_rewrite_as_sinh(self, arg, **kwargs):
504
+ return -I*sinh(arg + pi*I/2)
505
+
506
+ def _eval_rewrite_as_tanh(self, arg, **kwargs):
507
+ tanh_half = tanh(S.Half*arg)**2
508
+ return (1 + tanh_half)/(1 - tanh_half)
509
+
510
+ def _eval_rewrite_as_coth(self, arg, **kwargs):
511
+ coth_half = coth(S.Half*arg)**2
512
+ return (coth_half + 1)/(coth_half - 1)
513
+
514
+ def _eval_rewrite_as_sech(self, arg, **kwargs):
515
+ return 1 / sech(arg)
516
+
517
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
518
+ arg = self.args[0].as_leading_term(x, logx=logx, cdir=cdir)
519
+ arg0 = arg.subs(x, 0)
520
+
521
+ if arg0 is S.NaN:
522
+ arg0 = arg.limit(x, 0, dir='-' if cdir.is_negative else '+')
523
+ if arg0.is_zero:
524
+ return S.One
525
+ elif arg0.is_finite:
526
+ return self.func(arg0)
527
+ else:
528
+ return self
529
+
530
+ def _eval_is_real(self):
531
+ arg = self.args[0]
532
+
533
+ # `cosh(x)` is real for real OR purely imaginary `x`
534
+ if arg.is_real or arg.is_imaginary:
535
+ return True
536
+
537
+ # cosh(a+ib) = cos(b)*cosh(a) + i*sin(b)*sinh(a)
538
+ # the imaginary part can be an expression like n*pi
539
+ # if not, check if the imaginary part is a number
540
+ re, im = arg.as_real_imag()
541
+ return (im%pi).is_zero
542
+
543
+ def _eval_is_positive(self):
544
+ # cosh(x+I*y) = cos(y)*cosh(x) + I*sin(y)*sinh(x)
545
+ # cosh(z) is positive iff it is real and the real part is positive.
546
+ # So we need sin(y)*sinh(x) = 0 which gives x=0 or y=n*pi
547
+ # Case 1 (y=n*pi): cosh(z) = (-1)**n * cosh(x) -> positive for n even
548
+ # Case 2 (x=0): cosh(z) = cos(y) -> positive when cos(y) is positive
549
+ z = self.args[0]
550
+
551
+ x, y = z.as_real_imag()
552
+ ymod = y % (2*pi)
553
+
554
+ yzero = ymod.is_zero
555
+ # shortcut if ymod is zero
556
+ if yzero:
557
+ return True
558
+
559
+ xzero = x.is_zero
560
+ # shortcut x is not zero
561
+ if xzero is False:
562
+ return yzero
563
+
564
+ return fuzzy_or([
565
+ # Case 1:
566
+ yzero,
567
+ # Case 2:
568
+ fuzzy_and([
569
+ xzero,
570
+ fuzzy_or([ymod < pi/2, ymod > 3*pi/2])
571
+ ])
572
+ ])
573
+
574
+
575
+ def _eval_is_nonnegative(self):
576
+ z = self.args[0]
577
+
578
+ x, y = z.as_real_imag()
579
+ ymod = y % (2*pi)
580
+
581
+ yzero = ymod.is_zero
582
+ # shortcut if ymod is zero
583
+ if yzero:
584
+ return True
585
+
586
+ xzero = x.is_zero
587
+ # shortcut x is not zero
588
+ if xzero is False:
589
+ return yzero
590
+
591
+ return fuzzy_or([
592
+ # Case 1:
593
+ yzero,
594
+ # Case 2:
595
+ fuzzy_and([
596
+ xzero,
597
+ fuzzy_or([ymod <= pi/2, ymod >= 3*pi/2])
598
+ ])
599
+ ])
600
+
601
+ def _eval_is_finite(self):
602
+ arg = self.args[0]
603
+ return arg.is_finite
604
+
605
+ def _eval_is_zero(self):
606
+ rest, ipi_mult = _peeloff_ipi(self.args[0])
607
+ if ipi_mult and rest.is_zero:
608
+ return (ipi_mult - S.Half).is_integer
609
+
610
+
611
+ class tanh(HyperbolicFunction):
612
+ r"""
613
+ ``tanh(x)`` is the hyperbolic tangent of ``x``.
614
+
615
+ The hyperbolic tangent function is $\frac{\sinh(x)}{\cosh(x)}$.
616
+
617
+ Examples
618
+ ========
619
+
620
+ >>> from sympy import tanh
621
+ >>> from sympy.abc import x
622
+ >>> tanh(x)
623
+ tanh(x)
624
+
625
+ See Also
626
+ ========
627
+
628
+ sinh, cosh, atanh
629
+ """
630
+
631
+ def fdiff(self, argindex=1):
632
+ if argindex == 1:
633
+ return S.One - tanh(self.args[0])**2
634
+ else:
635
+ raise ArgumentIndexError(self, argindex)
636
+
637
+ def inverse(self, argindex=1):
638
+ """
639
+ Returns the inverse of this function.
640
+ """
641
+ return atanh
642
+
643
+ @classmethod
644
+ def eval(cls, arg):
645
+ if arg.is_Number:
646
+ if arg is S.NaN:
647
+ return S.NaN
648
+ elif arg is S.Infinity:
649
+ return S.One
650
+ elif arg is S.NegativeInfinity:
651
+ return S.NegativeOne
652
+ elif arg.is_zero:
653
+ return S.Zero
654
+ elif arg.is_negative:
655
+ return -cls(-arg)
656
+ else:
657
+ if arg is S.ComplexInfinity:
658
+ return S.NaN
659
+
660
+ i_coeff = _imaginary_unit_as_coefficient(arg)
661
+
662
+ if i_coeff is not None:
663
+ if i_coeff.could_extract_minus_sign():
664
+ return -I * tan(-i_coeff)
665
+ return I * tan(i_coeff)
666
+ else:
667
+ if arg.could_extract_minus_sign():
668
+ return -cls(-arg)
669
+
670
+ if arg.is_Add:
671
+ x, m = _peeloff_ipi(arg)
672
+ if m:
673
+ tanhm = tanh(m*pi*I)
674
+ if tanhm is S.ComplexInfinity:
675
+ return coth(x)
676
+ else: # tanhm == 0
677
+ return tanh(x)
678
+
679
+ if arg.is_zero:
680
+ return S.Zero
681
+
682
+ if arg.func == asinh:
683
+ x = arg.args[0]
684
+ return x/sqrt(1 + x**2)
685
+
686
+ if arg.func == acosh:
687
+ x = arg.args[0]
688
+ return sqrt(x - 1) * sqrt(x + 1) / x
689
+
690
+ if arg.func == atanh:
691
+ return arg.args[0]
692
+
693
+ if arg.func == acoth:
694
+ return 1/arg.args[0]
695
+
696
+ @staticmethod
697
+ @cacheit
698
+ def taylor_term(n, x, *previous_terms):
699
+ if n < 0 or n % 2 == 0:
700
+ return S.Zero
701
+ else:
702
+ x = sympify(x)
703
+
704
+ a = 2**(n + 1)
705
+
706
+ B = bernoulli(n + 1)
707
+ F = factorial(n + 1)
708
+
709
+ return a*(a - 1) * B/F * x**n
710
+
711
+ def _eval_conjugate(self):
712
+ return self.func(self.args[0].conjugate())
713
+
714
+ def as_real_imag(self, deep=True, **hints):
715
+ if self.args[0].is_extended_real:
716
+ if deep:
717
+ hints['complex'] = False
718
+ return (self.expand(deep, **hints), S.Zero)
719
+ else:
720
+ return (self, S.Zero)
721
+ if deep:
722
+ re, im = self.args[0].expand(deep, **hints).as_real_imag()
723
+ else:
724
+ re, im = self.args[0].as_real_imag()
725
+ denom = sinh(re)**2 + cos(im)**2
726
+ return (sinh(re)*cosh(re)/denom, sin(im)*cos(im)/denom)
727
+
728
+ def _eval_expand_trig(self, **hints):
729
+ arg = self.args[0]
730
+ if arg.is_Add:
731
+ n = len(arg.args)
732
+ TX = [tanh(x, evaluate=False)._eval_expand_trig()
733
+ for x in arg.args]
734
+ p = [0, 0] # [den, num]
735
+ for i in range(n + 1):
736
+ p[i % 2] += symmetric_poly(i, TX)
737
+ return p[1]/p[0]
738
+ elif arg.is_Mul:
739
+ coeff, terms = arg.as_coeff_Mul()
740
+ if coeff.is_Integer and coeff > 1:
741
+ T = tanh(terms)
742
+ n = [nC(range(coeff), k)*T**k for k in range(1, coeff + 1, 2)]
743
+ d = [nC(range(coeff), k)*T**k for k in range(0, coeff + 1, 2)]
744
+ return Add(*n)/Add(*d)
745
+ return tanh(arg)
746
+
747
+ def _eval_rewrite_as_tractable(self, arg, limitvar=None, **kwargs):
748
+ neg_exp, pos_exp = exp(-arg), exp(arg)
749
+ return (pos_exp - neg_exp)/(pos_exp + neg_exp)
750
+
751
+ def _eval_rewrite_as_exp(self, arg, **kwargs):
752
+ neg_exp, pos_exp = exp(-arg), exp(arg)
753
+ return (pos_exp - neg_exp)/(pos_exp + neg_exp)
754
+
755
+ def _eval_rewrite_as_tan(self, arg, **kwargs):
756
+ return -I * tan(I * arg)
757
+
758
+ def _eval_rewrite_as_cot(self, arg, **kwargs):
759
+ return -I / cot(I * arg)
760
+
761
+ def _eval_rewrite_as_sinh(self, arg, **kwargs):
762
+ return I*sinh(arg)/sinh(pi*I/2 - arg)
763
+
764
+ def _eval_rewrite_as_cosh(self, arg, **kwargs):
765
+ return I*cosh(pi*I/2 - arg)/cosh(arg)
766
+
767
+ def _eval_rewrite_as_coth(self, arg, **kwargs):
768
+ return 1/coth(arg)
769
+
770
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
771
+ from sympy.series.order import Order
772
+ arg = self.args[0].as_leading_term(x)
773
+
774
+ if x in arg.free_symbols and Order(1, x).contains(arg):
775
+ return arg
776
+ else:
777
+ return self.func(arg)
778
+
779
+ def _eval_is_real(self):
780
+ arg = self.args[0]
781
+ if arg.is_real:
782
+ return True
783
+
784
+ re, im = arg.as_real_imag()
785
+
786
+ # if denom = 0, tanh(arg) = zoo
787
+ if re == 0 and im % pi == pi/2:
788
+ return None
789
+
790
+ # check if im is of the form n*pi/2 to make sin(2*im) = 0
791
+ # if not, im could be a number, return False in that case
792
+ return (im % (pi/2)).is_zero
793
+
794
+ def _eval_is_extended_real(self):
795
+ if self.args[0].is_extended_real:
796
+ return True
797
+
798
+ def _eval_is_positive(self):
799
+ if self.args[0].is_extended_real:
800
+ return self.args[0].is_positive
801
+
802
+ def _eval_is_negative(self):
803
+ if self.args[0].is_extended_real:
804
+ return self.args[0].is_negative
805
+
806
+ def _eval_is_finite(self):
807
+ arg = self.args[0]
808
+
809
+ re, im = arg.as_real_imag()
810
+ denom = cos(im)**2 + sinh(re)**2
811
+ if denom == 0:
812
+ return False
813
+ elif denom.is_number:
814
+ return True
815
+ if arg.is_extended_real:
816
+ return True
817
+
818
+ def _eval_is_zero(self):
819
+ arg = self.args[0]
820
+ if arg.is_zero:
821
+ return True
822
+
823
+
824
+ class coth(HyperbolicFunction):
825
+ r"""
826
+ ``coth(x)`` is the hyperbolic cotangent of ``x``.
827
+
828
+ The hyperbolic cotangent function is $\frac{\cosh(x)}{\sinh(x)}$.
829
+
830
+ Examples
831
+ ========
832
+
833
+ >>> from sympy import coth
834
+ >>> from sympy.abc import x
835
+ >>> coth(x)
836
+ coth(x)
837
+
838
+ See Also
839
+ ========
840
+
841
+ sinh, cosh, acoth
842
+ """
843
+
844
+ def fdiff(self, argindex=1):
845
+ if argindex == 1:
846
+ return -1/sinh(self.args[0])**2
847
+ else:
848
+ raise ArgumentIndexError(self, argindex)
849
+
850
+ def inverse(self, argindex=1):
851
+ """
852
+ Returns the inverse of this function.
853
+ """
854
+ return acoth
855
+
856
+ @classmethod
857
+ def eval(cls, arg):
858
+ if arg.is_Number:
859
+ if arg is S.NaN:
860
+ return S.NaN
861
+ elif arg is S.Infinity:
862
+ return S.One
863
+ elif arg is S.NegativeInfinity:
864
+ return S.NegativeOne
865
+ elif arg.is_zero:
866
+ return S.ComplexInfinity
867
+ elif arg.is_negative:
868
+ return -cls(-arg)
869
+ else:
870
+ if arg is S.ComplexInfinity:
871
+ return S.NaN
872
+
873
+ i_coeff = _imaginary_unit_as_coefficient(arg)
874
+
875
+ if i_coeff is not None:
876
+ if i_coeff.could_extract_minus_sign():
877
+ return I * cot(-i_coeff)
878
+ return -I * cot(i_coeff)
879
+ else:
880
+ if arg.could_extract_minus_sign():
881
+ return -cls(-arg)
882
+
883
+ if arg.is_Add:
884
+ x, m = _peeloff_ipi(arg)
885
+ if m:
886
+ cothm = coth(m*pi*I)
887
+ if cothm is S.ComplexInfinity:
888
+ return coth(x)
889
+ else: # cothm == 0
890
+ return tanh(x)
891
+
892
+ if arg.is_zero:
893
+ return S.ComplexInfinity
894
+
895
+ if arg.func == asinh:
896
+ x = arg.args[0]
897
+ return sqrt(1 + x**2)/x
898
+
899
+ if arg.func == acosh:
900
+ x = arg.args[0]
901
+ return x/(sqrt(x - 1) * sqrt(x + 1))
902
+
903
+ if arg.func == atanh:
904
+ return 1/arg.args[0]
905
+
906
+ if arg.func == acoth:
907
+ return arg.args[0]
908
+
909
+ @staticmethod
910
+ @cacheit
911
+ def taylor_term(n, x, *previous_terms):
912
+ if n == 0:
913
+ return 1 / sympify(x)
914
+ elif n < 0 or n % 2 == 0:
915
+ return S.Zero
916
+ else:
917
+ x = sympify(x)
918
+
919
+ B = bernoulli(n + 1)
920
+ F = factorial(n + 1)
921
+
922
+ return 2**(n + 1) * B/F * x**n
923
+
924
+ def _eval_conjugate(self):
925
+ return self.func(self.args[0].conjugate())
926
+
927
+ def as_real_imag(self, deep=True, **hints):
928
+ from sympy.functions.elementary.trigonometric import (cos, sin)
929
+ if self.args[0].is_extended_real:
930
+ if deep:
931
+ hints['complex'] = False
932
+ return (self.expand(deep, **hints), S.Zero)
933
+ else:
934
+ return (self, S.Zero)
935
+ if deep:
936
+ re, im = self.args[0].expand(deep, **hints).as_real_imag()
937
+ else:
938
+ re, im = self.args[0].as_real_imag()
939
+ denom = sinh(re)**2 + sin(im)**2
940
+ return (sinh(re)*cosh(re)/denom, -sin(im)*cos(im)/denom)
941
+
942
+ def _eval_rewrite_as_tractable(self, arg, limitvar=None, **kwargs):
943
+ neg_exp, pos_exp = exp(-arg), exp(arg)
944
+ return (pos_exp + neg_exp)/(pos_exp - neg_exp)
945
+
946
+ def _eval_rewrite_as_exp(self, arg, **kwargs):
947
+ neg_exp, pos_exp = exp(-arg), exp(arg)
948
+ return (pos_exp + neg_exp)/(pos_exp - neg_exp)
949
+
950
+ def _eval_rewrite_as_sinh(self, arg, **kwargs):
951
+ return -I*sinh(pi*I/2 - arg)/sinh(arg)
952
+
953
+ def _eval_rewrite_as_cosh(self, arg, **kwargs):
954
+ return -I*cosh(arg)/cosh(pi*I/2 - arg)
955
+
956
+ def _eval_rewrite_as_tanh(self, arg, **kwargs):
957
+ return 1/tanh(arg)
958
+
959
+ def _eval_is_positive(self):
960
+ if self.args[0].is_extended_real:
961
+ return self.args[0].is_positive
962
+
963
+ def _eval_is_negative(self):
964
+ if self.args[0].is_extended_real:
965
+ return self.args[0].is_negative
966
+
967
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
968
+ from sympy.series.order import Order
969
+ arg = self.args[0].as_leading_term(x)
970
+
971
+ if x in arg.free_symbols and Order(1, x).contains(arg):
972
+ return 1/arg
973
+ else:
974
+ return self.func(arg)
975
+
976
+ def _eval_expand_trig(self, **hints):
977
+ arg = self.args[0]
978
+ if arg.is_Add:
979
+ CX = [coth(x, evaluate=False)._eval_expand_trig() for x in arg.args]
980
+ p = [[], []]
981
+ n = len(arg.args)
982
+ for i in range(n, -1, -1):
983
+ p[(n - i) % 2].append(symmetric_poly(i, CX))
984
+ return Add(*p[0])/Add(*p[1])
985
+ elif arg.is_Mul:
986
+ coeff, x = arg.as_coeff_Mul(rational=True)
987
+ if coeff.is_Integer and coeff > 1:
988
+ c = coth(x, evaluate=False)
989
+ p = [[], []]
990
+ for i in range(coeff, -1, -1):
991
+ p[(coeff - i) % 2].append(binomial(coeff, i)*c**i)
992
+ return Add(*p[0])/Add(*p[1])
993
+ return coth(arg)
994
+
995
+
996
+ class ReciprocalHyperbolicFunction(HyperbolicFunction):
997
+ """Base class for reciprocal functions of hyperbolic functions. """
998
+
999
+ #To be defined in class
1000
+ _reciprocal_of = None
1001
+ _is_even: FuzzyBool = None
1002
+ _is_odd: FuzzyBool = None
1003
+
1004
+ @classmethod
1005
+ def eval(cls, arg):
1006
+ if arg.could_extract_minus_sign():
1007
+ if cls._is_even:
1008
+ return cls(-arg)
1009
+ if cls._is_odd:
1010
+ return -cls(-arg)
1011
+
1012
+ t = cls._reciprocal_of.eval(arg)
1013
+ if hasattr(arg, 'inverse') and arg.inverse() == cls:
1014
+ return arg.args[0]
1015
+ return 1/t if t is not None else t
1016
+
1017
+ def _call_reciprocal(self, method_name, *args, **kwargs):
1018
+ # Calls method_name on _reciprocal_of
1019
+ o = self._reciprocal_of(self.args[0])
1020
+ return getattr(o, method_name)(*args, **kwargs)
1021
+
1022
+ def _calculate_reciprocal(self, method_name, *args, **kwargs):
1023
+ # If calling method_name on _reciprocal_of returns a value != None
1024
+ # then return the reciprocal of that value
1025
+ t = self._call_reciprocal(method_name, *args, **kwargs)
1026
+ return 1/t if t is not None else t
1027
+
1028
+ def _rewrite_reciprocal(self, method_name, arg):
1029
+ # Special handling for rewrite functions. If reciprocal rewrite returns
1030
+ # unmodified expression, then return None
1031
+ t = self._call_reciprocal(method_name, arg)
1032
+ if t is not None and t != self._reciprocal_of(arg):
1033
+ return 1/t
1034
+
1035
+ def _eval_rewrite_as_exp(self, arg, **kwargs):
1036
+ return self._rewrite_reciprocal("_eval_rewrite_as_exp", arg)
1037
+
1038
+ def _eval_rewrite_as_tractable(self, arg, limitvar=None, **kwargs):
1039
+ return self._rewrite_reciprocal("_eval_rewrite_as_tractable", arg)
1040
+
1041
+ def _eval_rewrite_as_tanh(self, arg, **kwargs):
1042
+ return self._rewrite_reciprocal("_eval_rewrite_as_tanh", arg)
1043
+
1044
+ def _eval_rewrite_as_coth(self, arg, **kwargs):
1045
+ return self._rewrite_reciprocal("_eval_rewrite_as_coth", arg)
1046
+
1047
+ def as_real_imag(self, deep = True, **hints):
1048
+ return (1 / self._reciprocal_of(self.args[0])).as_real_imag(deep, **hints)
1049
+
1050
+ def _eval_conjugate(self):
1051
+ return self.func(self.args[0].conjugate())
1052
+
1053
+ def _eval_expand_complex(self, deep=True, **hints):
1054
+ re_part, im_part = self.as_real_imag(deep=True, **hints)
1055
+ return re_part + I*im_part
1056
+
1057
+ def _eval_expand_trig(self, **hints):
1058
+ return self._calculate_reciprocal("_eval_expand_trig", **hints)
1059
+
1060
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
1061
+ return (1/self._reciprocal_of(self.args[0]))._eval_as_leading_term(x)
1062
+
1063
+ def _eval_is_extended_real(self):
1064
+ return self._reciprocal_of(self.args[0]).is_extended_real
1065
+
1066
+ def _eval_is_finite(self):
1067
+ return (1/self._reciprocal_of(self.args[0])).is_finite
1068
+
1069
+
1070
+ class csch(ReciprocalHyperbolicFunction):
1071
+ r"""
1072
+ ``csch(x)`` is the hyperbolic cosecant of ``x``.
1073
+
1074
+ The hyperbolic cosecant function is $\frac{2}{e^x - e^{-x}}$
1075
+
1076
+ Examples
1077
+ ========
1078
+
1079
+ >>> from sympy import csch
1080
+ >>> from sympy.abc import x
1081
+ >>> csch(x)
1082
+ csch(x)
1083
+
1084
+ See Also
1085
+ ========
1086
+
1087
+ sinh, cosh, tanh, sech, asinh, acosh
1088
+ """
1089
+
1090
+ _reciprocal_of = sinh
1091
+ _is_odd = True
1092
+
1093
+ def fdiff(self, argindex=1):
1094
+ """
1095
+ Returns the first derivative of this function
1096
+ """
1097
+ if argindex == 1:
1098
+ return -coth(self.args[0]) * csch(self.args[0])
1099
+ else:
1100
+ raise ArgumentIndexError(self, argindex)
1101
+
1102
+ @staticmethod
1103
+ @cacheit
1104
+ def taylor_term(n, x, *previous_terms):
1105
+ """
1106
+ Returns the next term in the Taylor series expansion
1107
+ """
1108
+ if n == 0:
1109
+ return 1/sympify(x)
1110
+ elif n < 0 or n % 2 == 0:
1111
+ return S.Zero
1112
+ else:
1113
+ x = sympify(x)
1114
+
1115
+ B = bernoulli(n + 1)
1116
+ F = factorial(n + 1)
1117
+
1118
+ return 2 * (1 - 2**n) * B/F * x**n
1119
+
1120
+ def _eval_rewrite_as_sin(self, arg, **kwargs):
1121
+ return I / sin(I * arg)
1122
+
1123
+ def _eval_rewrite_as_csc(self, arg, **kwargs):
1124
+ return I * csc(I * arg)
1125
+
1126
+ def _eval_rewrite_as_cosh(self, arg, **kwargs):
1127
+ return I / cosh(arg + I * pi / 2)
1128
+
1129
+ def _eval_rewrite_as_sinh(self, arg, **kwargs):
1130
+ return 1 / sinh(arg)
1131
+
1132
+ def _eval_is_positive(self):
1133
+ if self.args[0].is_extended_real:
1134
+ return self.args[0].is_positive
1135
+
1136
+ def _eval_is_negative(self):
1137
+ if self.args[0].is_extended_real:
1138
+ return self.args[0].is_negative
1139
+
1140
+
1141
+ class sech(ReciprocalHyperbolicFunction):
1142
+ r"""
1143
+ ``sech(x)`` is the hyperbolic secant of ``x``.
1144
+
1145
+ The hyperbolic secant function is $\frac{2}{e^x + e^{-x}}$
1146
+
1147
+ Examples
1148
+ ========
1149
+
1150
+ >>> from sympy import sech
1151
+ >>> from sympy.abc import x
1152
+ >>> sech(x)
1153
+ sech(x)
1154
+
1155
+ See Also
1156
+ ========
1157
+
1158
+ sinh, cosh, tanh, coth, csch, asinh, acosh
1159
+ """
1160
+
1161
+ _reciprocal_of = cosh
1162
+ _is_even = True
1163
+
1164
+ def fdiff(self, argindex=1):
1165
+ if argindex == 1:
1166
+ return - tanh(self.args[0])*sech(self.args[0])
1167
+ else:
1168
+ raise ArgumentIndexError(self, argindex)
1169
+
1170
+ @staticmethod
1171
+ @cacheit
1172
+ def taylor_term(n, x, *previous_terms):
1173
+ if n < 0 or n % 2 == 1:
1174
+ return S.Zero
1175
+ else:
1176
+ x = sympify(x)
1177
+ return euler(n) / factorial(n) * x**(n)
1178
+
1179
+ def _eval_rewrite_as_cos(self, arg, **kwargs):
1180
+ return 1 / cos(I * arg)
1181
+
1182
+ def _eval_rewrite_as_sec(self, arg, **kwargs):
1183
+ return sec(I * arg)
1184
+
1185
+ def _eval_rewrite_as_sinh(self, arg, **kwargs):
1186
+ return I / sinh(arg + I * pi /2)
1187
+
1188
+ def _eval_rewrite_as_cosh(self, arg, **kwargs):
1189
+ return 1 / cosh(arg)
1190
+
1191
+ def _eval_is_positive(self):
1192
+ if self.args[0].is_extended_real:
1193
+ return True
1194
+
1195
+
1196
+ ###############################################################################
1197
+ ############################# HYPERBOLIC INVERSES #############################
1198
+ ###############################################################################
1199
+
1200
+ class InverseHyperbolicFunction(Function):
1201
+ """Base class for inverse hyperbolic functions."""
1202
+
1203
+ pass
1204
+
1205
+
1206
+ class asinh(InverseHyperbolicFunction):
1207
+ """
1208
+ ``asinh(x)`` is the inverse hyperbolic sine of ``x``.
1209
+
1210
+ The inverse hyperbolic sine function.
1211
+
1212
+ Examples
1213
+ ========
1214
+
1215
+ >>> from sympy import asinh
1216
+ >>> from sympy.abc import x
1217
+ >>> asinh(x).diff(x)
1218
+ 1/sqrt(x**2 + 1)
1219
+ >>> asinh(1)
1220
+ log(1 + sqrt(2))
1221
+
1222
+ See Also
1223
+ ========
1224
+
1225
+ acosh, atanh, sinh
1226
+ """
1227
+
1228
+ def fdiff(self, argindex=1):
1229
+ if argindex == 1:
1230
+ return 1/sqrt(self.args[0]**2 + 1)
1231
+ else:
1232
+ raise ArgumentIndexError(self, argindex)
1233
+
1234
+ @classmethod
1235
+ def eval(cls, arg):
1236
+ if arg.is_Number:
1237
+ if arg is S.NaN:
1238
+ return S.NaN
1239
+ elif arg is S.Infinity:
1240
+ return S.Infinity
1241
+ elif arg is S.NegativeInfinity:
1242
+ return S.NegativeInfinity
1243
+ elif arg.is_zero:
1244
+ return S.Zero
1245
+ elif arg is S.One:
1246
+ return log(sqrt(2) + 1)
1247
+ elif arg is S.NegativeOne:
1248
+ return log(sqrt(2) - 1)
1249
+ elif arg.is_negative:
1250
+ return -cls(-arg)
1251
+ else:
1252
+ if arg is S.ComplexInfinity:
1253
+ return S.ComplexInfinity
1254
+
1255
+ if arg.is_zero:
1256
+ return S.Zero
1257
+
1258
+ i_coeff = _imaginary_unit_as_coefficient(arg)
1259
+
1260
+ if i_coeff is not None:
1261
+ return I * asin(i_coeff)
1262
+ else:
1263
+ if arg.could_extract_minus_sign():
1264
+ return -cls(-arg)
1265
+
1266
+ if isinstance(arg, sinh) and arg.args[0].is_number:
1267
+ z = arg.args[0]
1268
+ if z.is_real:
1269
+ return z
1270
+ r, i = match_real_imag(z)
1271
+ if r is not None and i is not None:
1272
+ f = floor((i + pi/2)/pi)
1273
+ m = z - I*pi*f
1274
+ even = f.is_even
1275
+ if even is True:
1276
+ return m
1277
+ elif even is False:
1278
+ return -m
1279
+
1280
+ @staticmethod
1281
+ @cacheit
1282
+ def taylor_term(n, x, *previous_terms):
1283
+ if n < 0 or n % 2 == 0:
1284
+ return S.Zero
1285
+ else:
1286
+ x = sympify(x)
1287
+ if len(previous_terms) >= 2 and n > 2:
1288
+ p = previous_terms[-2]
1289
+ return -p * (n - 2)**2/(n*(n - 1)) * x**2
1290
+ else:
1291
+ k = (n - 1) // 2
1292
+ R = RisingFactorial(S.Half, k)
1293
+ F = factorial(k)
1294
+ return S.NegativeOne**k * R / F * x**n / n
1295
+
1296
+ def _eval_as_leading_term(self, x, logx=None, cdir=0): # asinh
1297
+ arg = self.args[0]
1298
+ x0 = arg.subs(x, 0).cancel()
1299
+ if x0.is_zero:
1300
+ return arg.as_leading_term(x)
1301
+ # Handling branch points
1302
+ if x0 in (-I, I, S.ComplexInfinity):
1303
+ return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir)
1304
+ # Handling points lying on branch cuts (-I*oo, -I) U (I, I*oo)
1305
+ if (1 + x0**2).is_negative:
1306
+ ndir = arg.dir(x, cdir if cdir else 1)
1307
+ if re(ndir).is_positive:
1308
+ if im(x0).is_negative:
1309
+ return -self.func(x0) - I*pi
1310
+ elif re(ndir).is_negative:
1311
+ if im(x0).is_positive:
1312
+ return -self.func(x0) + I*pi
1313
+ else:
1314
+ return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir)
1315
+ return self.func(x0)
1316
+
1317
+ def _eval_nseries(self, x, n, logx, cdir=0): # asinh
1318
+ arg = self.args[0]
1319
+ arg0 = arg.subs(x, 0)
1320
+
1321
+ # Handling branch points
1322
+ if arg0 in (I, -I):
1323
+ return self.rewrite(log)._eval_nseries(x, n, logx=logx, cdir=cdir)
1324
+
1325
+ res = Function._eval_nseries(self, x, n=n, logx=logx)
1326
+ if arg0 is S.ComplexInfinity:
1327
+ return res
1328
+
1329
+ # Handling points lying on branch cuts (-I*oo, -I) U (I, I*oo)
1330
+ if (1 + arg0**2).is_negative:
1331
+ ndir = arg.dir(x, cdir if cdir else 1)
1332
+ if re(ndir).is_positive:
1333
+ if im(arg0).is_negative:
1334
+ return -res - I*pi
1335
+ elif re(ndir).is_negative:
1336
+ if im(arg0).is_positive:
1337
+ return -res + I*pi
1338
+ else:
1339
+ return self.rewrite(log)._eval_nseries(x, n, logx=logx, cdir=cdir)
1340
+ return res
1341
+
1342
+ def _eval_rewrite_as_log(self, x, **kwargs):
1343
+ return log(x + sqrt(x**2 + 1))
1344
+
1345
+ _eval_rewrite_as_tractable = _eval_rewrite_as_log
1346
+
1347
+ def _eval_rewrite_as_atanh(self, x, **kwargs):
1348
+ return atanh(x/sqrt(1 + x**2))
1349
+
1350
+ def _eval_rewrite_as_acosh(self, x, **kwargs):
1351
+ ix = I*x
1352
+ return I*(sqrt(1 - ix)/sqrt(ix - 1) * acosh(ix) - pi/2)
1353
+
1354
+ def _eval_rewrite_as_asin(self, x, **kwargs):
1355
+ return -I * asin(I * x)
1356
+
1357
+ def _eval_rewrite_as_acos(self, x, **kwargs):
1358
+ return I * acos(I * x) - I*pi/2
1359
+
1360
+ def inverse(self, argindex=1):
1361
+ """
1362
+ Returns the inverse of this function.
1363
+ """
1364
+ return sinh
1365
+
1366
+ def _eval_is_zero(self):
1367
+ return self.args[0].is_zero
1368
+
1369
+
1370
+ class acosh(InverseHyperbolicFunction):
1371
+ """
1372
+ ``acosh(x)`` is the inverse hyperbolic cosine of ``x``.
1373
+
1374
+ The inverse hyperbolic cosine function.
1375
+
1376
+ Examples
1377
+ ========
1378
+
1379
+ >>> from sympy import acosh
1380
+ >>> from sympy.abc import x
1381
+ >>> acosh(x).diff(x)
1382
+ 1/(sqrt(x - 1)*sqrt(x + 1))
1383
+ >>> acosh(1)
1384
+ 0
1385
+
1386
+ See Also
1387
+ ========
1388
+
1389
+ asinh, atanh, cosh
1390
+ """
1391
+
1392
+ def fdiff(self, argindex=1):
1393
+ if argindex == 1:
1394
+ arg = self.args[0]
1395
+ return 1/(sqrt(arg - 1)*sqrt(arg + 1))
1396
+ else:
1397
+ raise ArgumentIndexError(self, argindex)
1398
+
1399
+ @classmethod
1400
+ def eval(cls, arg):
1401
+ if arg.is_Number:
1402
+ if arg is S.NaN:
1403
+ return S.NaN
1404
+ elif arg is S.Infinity:
1405
+ return S.Infinity
1406
+ elif arg is S.NegativeInfinity:
1407
+ return S.Infinity
1408
+ elif arg.is_zero:
1409
+ return pi*I / 2
1410
+ elif arg is S.One:
1411
+ return S.Zero
1412
+ elif arg is S.NegativeOne:
1413
+ return pi*I
1414
+
1415
+ if arg.is_number:
1416
+ cst_table = _acosh_table()
1417
+
1418
+ if arg in cst_table:
1419
+ if arg.is_extended_real:
1420
+ return cst_table[arg]*I
1421
+ return cst_table[arg]
1422
+
1423
+ if arg is S.ComplexInfinity:
1424
+ return S.ComplexInfinity
1425
+ if arg == I*S.Infinity:
1426
+ return S.Infinity + I*pi/2
1427
+ if arg == -I*S.Infinity:
1428
+ return S.Infinity - I*pi/2
1429
+
1430
+ if arg.is_zero:
1431
+ return pi*I*S.Half
1432
+
1433
+ if isinstance(arg, cosh) and arg.args[0].is_number:
1434
+ z = arg.args[0]
1435
+ if z.is_real:
1436
+ return Abs(z)
1437
+ r, i = match_real_imag(z)
1438
+ if r is not None and i is not None:
1439
+ f = floor(i/pi)
1440
+ m = z - I*pi*f
1441
+ even = f.is_even
1442
+ if even is True:
1443
+ if r.is_nonnegative:
1444
+ return m
1445
+ elif r.is_negative:
1446
+ return -m
1447
+ elif even is False:
1448
+ m -= I*pi
1449
+ if r.is_nonpositive:
1450
+ return -m
1451
+ elif r.is_positive:
1452
+ return m
1453
+
1454
+ @staticmethod
1455
+ @cacheit
1456
+ def taylor_term(n, x, *previous_terms):
1457
+ if n == 0:
1458
+ return I*pi/2
1459
+ elif n < 0 or n % 2 == 0:
1460
+ return S.Zero
1461
+ else:
1462
+ x = sympify(x)
1463
+ if len(previous_terms) >= 2 and n > 2:
1464
+ p = previous_terms[-2]
1465
+ return p * (n - 2)**2/(n*(n - 1)) * x**2
1466
+ else:
1467
+ k = (n - 1) // 2
1468
+ R = RisingFactorial(S.Half, k)
1469
+ F = factorial(k)
1470
+ return -R / F * I * x**n / n
1471
+
1472
+ def _eval_as_leading_term(self, x, logx=None, cdir=0): # acosh
1473
+ arg = self.args[0]
1474
+ x0 = arg.subs(x, 0).cancel()
1475
+ # Handling branch points
1476
+ if x0 in (-S.One, S.Zero, S.One, S.ComplexInfinity):
1477
+ return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir)
1478
+ # Handling points lying on branch cuts (-oo, 1)
1479
+ if (x0 - 1).is_negative:
1480
+ ndir = arg.dir(x, cdir if cdir else 1)
1481
+ if im(ndir).is_negative:
1482
+ if (x0 + 1).is_negative:
1483
+ return self.func(x0) - 2*I*pi
1484
+ return -self.func(x0)
1485
+ elif not im(ndir).is_positive:
1486
+ return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir)
1487
+ return self.func(x0)
1488
+
1489
+ def _eval_nseries(self, x, n, logx, cdir=0): # acosh
1490
+ arg = self.args[0]
1491
+ arg0 = arg.subs(x, 0)
1492
+
1493
+ # Handling branch points
1494
+ if arg0 in (S.One, S.NegativeOne):
1495
+ return self.rewrite(log)._eval_nseries(x, n, logx=logx, cdir=cdir)
1496
+
1497
+ res = Function._eval_nseries(self, x, n=n, logx=logx)
1498
+ if arg0 is S.ComplexInfinity:
1499
+ return res
1500
+
1501
+ # Handling points lying on branch cuts (-oo, 1)
1502
+ if (arg0 - 1).is_negative:
1503
+ ndir = arg.dir(x, cdir if cdir else 1)
1504
+ if im(ndir).is_negative:
1505
+ if (arg0 + 1).is_negative:
1506
+ return res - 2*I*pi
1507
+ return -res
1508
+ elif not im(ndir).is_positive:
1509
+ return self.rewrite(log)._eval_nseries(x, n, logx=logx, cdir=cdir)
1510
+ return res
1511
+
1512
+ def _eval_rewrite_as_log(self, x, **kwargs):
1513
+ return log(x + sqrt(x + 1) * sqrt(x - 1))
1514
+
1515
+ _eval_rewrite_as_tractable = _eval_rewrite_as_log
1516
+
1517
+ def _eval_rewrite_as_acos(self, x, **kwargs):
1518
+ return sqrt(x - 1)/sqrt(1 - x) * acos(x)
1519
+
1520
+ def _eval_rewrite_as_asin(self, x, **kwargs):
1521
+ return sqrt(x - 1)/sqrt(1 - x) * (pi/2 - asin(x))
1522
+
1523
+ def _eval_rewrite_as_asinh(self, x, **kwargs):
1524
+ return sqrt(x - 1)/sqrt(1 - x) * (pi/2 + I*asinh(I*x))
1525
+
1526
+ def _eval_rewrite_as_atanh(self, x, **kwargs):
1527
+ sxm1 = sqrt(x - 1)
1528
+ s1mx = sqrt(1 - x)
1529
+ sx2m1 = sqrt(x**2 - 1)
1530
+ return (pi/2*sxm1/s1mx*(1 - x * sqrt(1/x**2)) +
1531
+ sxm1*sqrt(x + 1)/sx2m1 * atanh(sx2m1/x))
1532
+
1533
+ def inverse(self, argindex=1):
1534
+ """
1535
+ Returns the inverse of this function.
1536
+ """
1537
+ return cosh
1538
+
1539
+ def _eval_is_zero(self):
1540
+ if (self.args[0] - 1).is_zero:
1541
+ return True
1542
+
1543
+
1544
+ class atanh(InverseHyperbolicFunction):
1545
+ """
1546
+ ``atanh(x)`` is the inverse hyperbolic tangent of ``x``.
1547
+
1548
+ The inverse hyperbolic tangent function.
1549
+
1550
+ Examples
1551
+ ========
1552
+
1553
+ >>> from sympy import atanh
1554
+ >>> from sympy.abc import x
1555
+ >>> atanh(x).diff(x)
1556
+ 1/(1 - x**2)
1557
+
1558
+ See Also
1559
+ ========
1560
+
1561
+ asinh, acosh, tanh
1562
+ """
1563
+
1564
+ def fdiff(self, argindex=1):
1565
+ if argindex == 1:
1566
+ return 1/(1 - self.args[0]**2)
1567
+ else:
1568
+ raise ArgumentIndexError(self, argindex)
1569
+
1570
+ @classmethod
1571
+ def eval(cls, arg):
1572
+ if arg.is_Number:
1573
+ if arg is S.NaN:
1574
+ return S.NaN
1575
+ elif arg.is_zero:
1576
+ return S.Zero
1577
+ elif arg is S.One:
1578
+ return S.Infinity
1579
+ elif arg is S.NegativeOne:
1580
+ return S.NegativeInfinity
1581
+ elif arg is S.Infinity:
1582
+ return -I * atan(arg)
1583
+ elif arg is S.NegativeInfinity:
1584
+ return I * atan(-arg)
1585
+ elif arg.is_negative:
1586
+ return -cls(-arg)
1587
+ else:
1588
+ if arg is S.ComplexInfinity:
1589
+ from sympy.calculus.accumulationbounds import AccumBounds
1590
+ return I*AccumBounds(-pi/2, pi/2)
1591
+
1592
+ i_coeff = _imaginary_unit_as_coefficient(arg)
1593
+
1594
+ if i_coeff is not None:
1595
+ return I * atan(i_coeff)
1596
+ else:
1597
+ if arg.could_extract_minus_sign():
1598
+ return -cls(-arg)
1599
+
1600
+ if arg.is_zero:
1601
+ return S.Zero
1602
+
1603
+ if isinstance(arg, tanh) and arg.args[0].is_number:
1604
+ z = arg.args[0]
1605
+ if z.is_real:
1606
+ return z
1607
+ r, i = match_real_imag(z)
1608
+ if r is not None and i is not None:
1609
+ f = floor(2*i/pi)
1610
+ even = f.is_even
1611
+ m = z - I*f*pi/2
1612
+ if even is True:
1613
+ return m
1614
+ elif even is False:
1615
+ return m - I*pi/2
1616
+
1617
+ @staticmethod
1618
+ @cacheit
1619
+ def taylor_term(n, x, *previous_terms):
1620
+ if n < 0 or n % 2 == 0:
1621
+ return S.Zero
1622
+ else:
1623
+ x = sympify(x)
1624
+ return x**n / n
1625
+
1626
+ def _eval_as_leading_term(self, x, logx=None, cdir=0): # atanh
1627
+ arg = self.args[0]
1628
+ x0 = arg.subs(x, 0).cancel()
1629
+ if x0.is_zero:
1630
+ return arg.as_leading_term(x)
1631
+ # Handling branch points
1632
+ if x0 in (-S.One, S.One, S.ComplexInfinity):
1633
+ return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir)
1634
+ # Handling points lying on branch cuts (-oo, -1] U [1, oo)
1635
+ if (1 - x0**2).is_negative:
1636
+ ndir = arg.dir(x, cdir if cdir else 1)
1637
+ if im(ndir).is_negative:
1638
+ if x0.is_negative:
1639
+ return self.func(x0) - I*pi
1640
+ elif im(ndir).is_positive:
1641
+ if x0.is_positive:
1642
+ return self.func(x0) + I*pi
1643
+ else:
1644
+ return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir)
1645
+ return self.func(x0)
1646
+
1647
+ def _eval_nseries(self, x, n, logx, cdir=0): # atanh
1648
+ arg = self.args[0]
1649
+ arg0 = arg.subs(x, 0)
1650
+
1651
+ # Handling branch points
1652
+ if arg0 in (S.One, S.NegativeOne):
1653
+ return self.rewrite(log)._eval_nseries(x, n, logx=logx, cdir=cdir)
1654
+
1655
+ res = Function._eval_nseries(self, x, n=n, logx=logx)
1656
+ if arg0 is S.ComplexInfinity:
1657
+ return res
1658
+
1659
+ # Handling points lying on branch cuts (-oo, -1] U [1, oo)
1660
+ if (1 - arg0**2).is_negative:
1661
+ ndir = arg.dir(x, cdir if cdir else 1)
1662
+ if im(ndir).is_negative:
1663
+ if arg0.is_negative:
1664
+ return res - I*pi
1665
+ elif im(ndir).is_positive:
1666
+ if arg0.is_positive:
1667
+ return res + I*pi
1668
+ else:
1669
+ return self.rewrite(log)._eval_nseries(x, n, logx=logx, cdir=cdir)
1670
+ return res
1671
+
1672
+ def _eval_rewrite_as_log(self, x, **kwargs):
1673
+ return (log(1 + x) - log(1 - x)) / 2
1674
+
1675
+ _eval_rewrite_as_tractable = _eval_rewrite_as_log
1676
+
1677
+ def _eval_rewrite_as_asinh(self, x, **kwargs):
1678
+ f = sqrt(1/(x**2 - 1))
1679
+ return (pi*x/(2*sqrt(-x**2)) -
1680
+ sqrt(-x)*sqrt(1 - x**2)/sqrt(x)*f*asinh(f))
1681
+
1682
+ def _eval_is_zero(self):
1683
+ if self.args[0].is_zero:
1684
+ return True
1685
+
1686
+ def _eval_is_imaginary(self):
1687
+ return self.args[0].is_imaginary
1688
+
1689
+ def inverse(self, argindex=1):
1690
+ """
1691
+ Returns the inverse of this function.
1692
+ """
1693
+ return tanh
1694
+
1695
+
1696
+ class acoth(InverseHyperbolicFunction):
1697
+ """
1698
+ ``acoth(x)`` is the inverse hyperbolic cotangent of ``x``.
1699
+
1700
+ The inverse hyperbolic cotangent function.
1701
+
1702
+ Examples
1703
+ ========
1704
+
1705
+ >>> from sympy import acoth
1706
+ >>> from sympy.abc import x
1707
+ >>> acoth(x).diff(x)
1708
+ 1/(1 - x**2)
1709
+
1710
+ See Also
1711
+ ========
1712
+
1713
+ asinh, acosh, coth
1714
+ """
1715
+
1716
+ def fdiff(self, argindex=1):
1717
+ if argindex == 1:
1718
+ return 1/(1 - self.args[0]**2)
1719
+ else:
1720
+ raise ArgumentIndexError(self, argindex)
1721
+
1722
+ @classmethod
1723
+ def eval(cls, arg):
1724
+ if arg.is_Number:
1725
+ if arg is S.NaN:
1726
+ return S.NaN
1727
+ elif arg is S.Infinity:
1728
+ return S.Zero
1729
+ elif arg is S.NegativeInfinity:
1730
+ return S.Zero
1731
+ elif arg.is_zero:
1732
+ return pi*I / 2
1733
+ elif arg is S.One:
1734
+ return S.Infinity
1735
+ elif arg is S.NegativeOne:
1736
+ return S.NegativeInfinity
1737
+ elif arg.is_negative:
1738
+ return -cls(-arg)
1739
+ else:
1740
+ if arg is S.ComplexInfinity:
1741
+ return S.Zero
1742
+
1743
+ i_coeff = _imaginary_unit_as_coefficient(arg)
1744
+
1745
+ if i_coeff is not None:
1746
+ return -I * acot(i_coeff)
1747
+ else:
1748
+ if arg.could_extract_minus_sign():
1749
+ return -cls(-arg)
1750
+
1751
+ if arg.is_zero:
1752
+ return pi*I*S.Half
1753
+
1754
+ @staticmethod
1755
+ @cacheit
1756
+ def taylor_term(n, x, *previous_terms):
1757
+ if n == 0:
1758
+ return -I*pi/2
1759
+ elif n < 0 or n % 2 == 0:
1760
+ return S.Zero
1761
+ else:
1762
+ x = sympify(x)
1763
+ return x**n / n
1764
+
1765
+ def _eval_as_leading_term(self, x, logx=None, cdir=0): # acoth
1766
+ arg = self.args[0]
1767
+ x0 = arg.subs(x, 0).cancel()
1768
+ if x0 is S.ComplexInfinity:
1769
+ return (1/arg).as_leading_term(x)
1770
+ # Handling branch points
1771
+ if x0 in (-S.One, S.One, S.Zero):
1772
+ return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir)
1773
+ # Handling points lying on branch cuts [-1, 1]
1774
+ if x0.is_real and (1 - x0**2).is_positive:
1775
+ ndir = arg.dir(x, cdir if cdir else 1)
1776
+ if im(ndir).is_negative:
1777
+ if x0.is_positive:
1778
+ return self.func(x0) + I*pi
1779
+ elif im(ndir).is_positive:
1780
+ if x0.is_negative:
1781
+ return self.func(x0) - I*pi
1782
+ else:
1783
+ return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir)
1784
+ return self.func(x0)
1785
+
1786
+ def _eval_nseries(self, x, n, logx, cdir=0): # acoth
1787
+ arg = self.args[0]
1788
+ arg0 = arg.subs(x, 0)
1789
+
1790
+ # Handling branch points
1791
+ if arg0 in (S.One, S.NegativeOne):
1792
+ return self.rewrite(log)._eval_nseries(x, n, logx=logx, cdir=cdir)
1793
+
1794
+ res = Function._eval_nseries(self, x, n=n, logx=logx)
1795
+ if arg0 is S.ComplexInfinity:
1796
+ return res
1797
+
1798
+ # Handling points lying on branch cuts [-1, 1]
1799
+ if arg0.is_real and (1 - arg0**2).is_positive:
1800
+ ndir = arg.dir(x, cdir if cdir else 1)
1801
+ if im(ndir).is_negative:
1802
+ if arg0.is_positive:
1803
+ return res + I*pi
1804
+ elif im(ndir).is_positive:
1805
+ if arg0.is_negative:
1806
+ return res - I*pi
1807
+ else:
1808
+ return self.rewrite(log)._eval_nseries(x, n, logx=logx, cdir=cdir)
1809
+ return res
1810
+
1811
+ def _eval_rewrite_as_log(self, x, **kwargs):
1812
+ return (log(1 + 1/x) - log(1 - 1/x)) / 2
1813
+
1814
+ _eval_rewrite_as_tractable = _eval_rewrite_as_log
1815
+
1816
+ def _eval_rewrite_as_atanh(self, x, **kwargs):
1817
+ return atanh(1/x)
1818
+
1819
+ def _eval_rewrite_as_asinh(self, x, **kwargs):
1820
+ return (pi*I/2*(sqrt((x - 1)/x)*sqrt(x/(x - 1)) - sqrt(1 + 1/x)*sqrt(x/(x + 1))) +
1821
+ x*sqrt(1/x**2)*asinh(sqrt(1/(x**2 - 1))))
1822
+
1823
+ def inverse(self, argindex=1):
1824
+ """
1825
+ Returns the inverse of this function.
1826
+ """
1827
+ return coth
1828
+
1829
+
1830
+ class asech(InverseHyperbolicFunction):
1831
+ """
1832
+ ``asech(x)`` is the inverse hyperbolic secant of ``x``.
1833
+
1834
+ The inverse hyperbolic secant function.
1835
+
1836
+ Examples
1837
+ ========
1838
+
1839
+ >>> from sympy import asech, sqrt, S
1840
+ >>> from sympy.abc import x
1841
+ >>> asech(x).diff(x)
1842
+ -1/(x*sqrt(1 - x**2))
1843
+ >>> asech(1).diff(x)
1844
+ 0
1845
+ >>> asech(1)
1846
+ 0
1847
+ >>> asech(S(2))
1848
+ I*pi/3
1849
+ >>> asech(-sqrt(2))
1850
+ 3*I*pi/4
1851
+ >>> asech((sqrt(6) - sqrt(2)))
1852
+ I*pi/12
1853
+
1854
+ See Also
1855
+ ========
1856
+
1857
+ asinh, atanh, cosh, acoth
1858
+
1859
+ References
1860
+ ==========
1861
+
1862
+ .. [1] https://en.wikipedia.org/wiki/Hyperbolic_function
1863
+ .. [2] https://dlmf.nist.gov/4.37
1864
+ .. [3] https://functions.wolfram.com/ElementaryFunctions/ArcSech/
1865
+
1866
+ """
1867
+
1868
+ def fdiff(self, argindex=1):
1869
+ if argindex == 1:
1870
+ z = self.args[0]
1871
+ return -1/(z*sqrt(1 - z**2))
1872
+ else:
1873
+ raise ArgumentIndexError(self, argindex)
1874
+
1875
+ @classmethod
1876
+ def eval(cls, arg):
1877
+ if arg.is_Number:
1878
+ if arg is S.NaN:
1879
+ return S.NaN
1880
+ elif arg is S.Infinity:
1881
+ return pi*I / 2
1882
+ elif arg is S.NegativeInfinity:
1883
+ return pi*I / 2
1884
+ elif arg.is_zero:
1885
+ return S.Infinity
1886
+ elif arg is S.One:
1887
+ return S.Zero
1888
+ elif arg is S.NegativeOne:
1889
+ return pi*I
1890
+
1891
+ if arg.is_number:
1892
+ cst_table = _asech_table()
1893
+
1894
+ if arg in cst_table:
1895
+ if arg.is_extended_real:
1896
+ return cst_table[arg]*I
1897
+ return cst_table[arg]
1898
+
1899
+ if arg is S.ComplexInfinity:
1900
+ from sympy.calculus.accumulationbounds import AccumBounds
1901
+ return I*AccumBounds(-pi/2, pi/2)
1902
+
1903
+ if arg.is_zero:
1904
+ return S.Infinity
1905
+
1906
+ @staticmethod
1907
+ @cacheit
1908
+ def taylor_term(n, x, *previous_terms):
1909
+ if n == 0:
1910
+ return log(2 / x)
1911
+ elif n < 0 or n % 2 == 1:
1912
+ return S.Zero
1913
+ else:
1914
+ x = sympify(x)
1915
+ if len(previous_terms) > 2 and n > 2:
1916
+ p = previous_terms[-2]
1917
+ return p * ((n - 1)*(n-2)) * x**2/(4 * (n//2)**2)
1918
+ else:
1919
+ k = n // 2
1920
+ R = RisingFactorial(S.Half, k) * n
1921
+ F = factorial(k) * n // 2 * n // 2
1922
+ return -1 * R / F * x**n / 4
1923
+
1924
+ def _eval_as_leading_term(self, x, logx=None, cdir=0): # asech
1925
+ arg = self.args[0]
1926
+ x0 = arg.subs(x, 0).cancel()
1927
+ # Handling branch points
1928
+ if x0 in (-S.One, S.Zero, S.One, S.ComplexInfinity):
1929
+ return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir)
1930
+ # Handling points lying on branch cuts (-oo, 0] U (1, oo)
1931
+ if x0.is_negative or (1 - x0).is_negative:
1932
+ ndir = arg.dir(x, cdir if cdir else 1)
1933
+ if im(ndir).is_positive:
1934
+ if x0.is_positive or (x0 + 1).is_negative:
1935
+ return -self.func(x0)
1936
+ return self.func(x0) - 2*I*pi
1937
+ elif not im(ndir).is_negative:
1938
+ return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir)
1939
+ return self.func(x0)
1940
+
1941
+ def _eval_nseries(self, x, n, logx, cdir=0): # asech
1942
+ from sympy.series.order import O
1943
+ arg = self.args[0]
1944
+ arg0 = arg.subs(x, 0)
1945
+
1946
+ # Handling branch points
1947
+ if arg0 is S.One:
1948
+ t = Dummy('t', positive=True)
1949
+ ser = asech(S.One - t**2).rewrite(log).nseries(t, 0, 2*n)
1950
+ arg1 = S.One - self.args[0]
1951
+ f = arg1.as_leading_term(x)
1952
+ g = (arg1 - f)/ f
1953
+ if not g.is_meromorphic(x, 0): # cannot be expanded
1954
+ return O(1) if n == 0 else O(sqrt(x))
1955
+ res1 = sqrt(S.One + g)._eval_nseries(x, n=n, logx=logx)
1956
+ res = (res1.removeO()*sqrt(f)).expand()
1957
+ return ser.removeO().subs(t, res).expand().powsimp() + O(x**n, x)
1958
+
1959
+ if arg0 is S.NegativeOne:
1960
+ t = Dummy('t', positive=True)
1961
+ ser = asech(S.NegativeOne + t**2).rewrite(log).nseries(t, 0, 2*n)
1962
+ arg1 = S.One + self.args[0]
1963
+ f = arg1.as_leading_term(x)
1964
+ g = (arg1 - f)/ f
1965
+ if not g.is_meromorphic(x, 0): # cannot be expanded
1966
+ return O(1) if n == 0 else I*pi + O(sqrt(x))
1967
+ res1 = sqrt(S.One + g)._eval_nseries(x, n=n, logx=logx)
1968
+ res = (res1.removeO()*sqrt(f)).expand()
1969
+ return ser.removeO().subs(t, res).expand().powsimp() + O(x**n, x)
1970
+
1971
+ res = Function._eval_nseries(self, x, n=n, logx=logx)
1972
+ if arg0 is S.ComplexInfinity:
1973
+ return res
1974
+
1975
+ # Handling points lying on branch cuts (-oo, 0] U (1, oo)
1976
+ if arg0.is_negative or (1 - arg0).is_negative:
1977
+ ndir = arg.dir(x, cdir if cdir else 1)
1978
+ if im(ndir).is_positive:
1979
+ if arg0.is_positive or (arg0 + 1).is_negative:
1980
+ return -res
1981
+ return res - 2*I*pi
1982
+ elif not im(ndir).is_negative:
1983
+ return self.rewrite(log)._eval_nseries(x, n, logx=logx, cdir=cdir)
1984
+ return res
1985
+
1986
+ def inverse(self, argindex=1):
1987
+ """
1988
+ Returns the inverse of this function.
1989
+ """
1990
+ return sech
1991
+
1992
+ def _eval_rewrite_as_log(self, arg, **kwargs):
1993
+ return log(1/arg + sqrt(1/arg - 1) * sqrt(1/arg + 1))
1994
+
1995
+ _eval_rewrite_as_tractable = _eval_rewrite_as_log
1996
+
1997
+ def _eval_rewrite_as_acosh(self, arg, **kwargs):
1998
+ return acosh(1/arg)
1999
+
2000
+ def _eval_rewrite_as_asinh(self, arg, **kwargs):
2001
+ return sqrt(1/arg - 1)/sqrt(1 - 1/arg)*(I*asinh(I/arg)
2002
+ + pi*S.Half)
2003
+
2004
+ def _eval_rewrite_as_atanh(self, x, **kwargs):
2005
+ return (I*pi*(1 - sqrt(x)*sqrt(1/x) - I/2*sqrt(-x)/sqrt(x) - I/2*sqrt(x**2)/sqrt(-x**2))
2006
+ + sqrt(1/(x + 1))*sqrt(x + 1)*atanh(sqrt(1 - x**2)))
2007
+
2008
+ def _eval_rewrite_as_acsch(self, x, **kwargs):
2009
+ return sqrt(1/x - 1)/sqrt(1 - 1/x)*(pi/2 - I*acsch(I*x))
2010
+
2011
+
2012
+ class acsch(InverseHyperbolicFunction):
2013
+ """
2014
+ ``acsch(x)`` is the inverse hyperbolic cosecant of ``x``.
2015
+
2016
+ The inverse hyperbolic cosecant function.
2017
+
2018
+ Examples
2019
+ ========
2020
+
2021
+ >>> from sympy import acsch, sqrt, I
2022
+ >>> from sympy.abc import x
2023
+ >>> acsch(x).diff(x)
2024
+ -1/(x**2*sqrt(1 + x**(-2)))
2025
+ >>> acsch(1).diff(x)
2026
+ 0
2027
+ >>> acsch(1)
2028
+ log(1 + sqrt(2))
2029
+ >>> acsch(I)
2030
+ -I*pi/2
2031
+ >>> acsch(-2*I)
2032
+ I*pi/6
2033
+ >>> acsch(I*(sqrt(6) - sqrt(2)))
2034
+ -5*I*pi/12
2035
+
2036
+ See Also
2037
+ ========
2038
+
2039
+ asinh
2040
+
2041
+ References
2042
+ ==========
2043
+
2044
+ .. [1] https://en.wikipedia.org/wiki/Hyperbolic_function
2045
+ .. [2] https://dlmf.nist.gov/4.37
2046
+ .. [3] https://functions.wolfram.com/ElementaryFunctions/ArcCsch/
2047
+
2048
+ """
2049
+
2050
+ def fdiff(self, argindex=1):
2051
+ if argindex == 1:
2052
+ z = self.args[0]
2053
+ return -1/(z**2*sqrt(1 + 1/z**2))
2054
+ else:
2055
+ raise ArgumentIndexError(self, argindex)
2056
+
2057
+ @classmethod
2058
+ def eval(cls, arg):
2059
+ if arg.is_Number:
2060
+ if arg is S.NaN:
2061
+ return S.NaN
2062
+ elif arg is S.Infinity:
2063
+ return S.Zero
2064
+ elif arg is S.NegativeInfinity:
2065
+ return S.Zero
2066
+ elif arg.is_zero:
2067
+ return S.ComplexInfinity
2068
+ elif arg is S.One:
2069
+ return log(1 + sqrt(2))
2070
+ elif arg is S.NegativeOne:
2071
+ return - log(1 + sqrt(2))
2072
+
2073
+ if arg.is_number:
2074
+ cst_table = _acsch_table()
2075
+
2076
+ if arg in cst_table:
2077
+ return cst_table[arg]*I
2078
+
2079
+ if arg is S.ComplexInfinity:
2080
+ return S.Zero
2081
+
2082
+ if arg.is_infinite:
2083
+ return S.Zero
2084
+
2085
+ if arg.is_zero:
2086
+ return S.ComplexInfinity
2087
+
2088
+ if arg.could_extract_minus_sign():
2089
+ return -cls(-arg)
2090
+
2091
+ @staticmethod
2092
+ @cacheit
2093
+ def taylor_term(n, x, *previous_terms):
2094
+ if n == 0:
2095
+ return log(2 / x)
2096
+ elif n < 0 or n % 2 == 1:
2097
+ return S.Zero
2098
+ else:
2099
+ x = sympify(x)
2100
+ if len(previous_terms) > 2 and n > 2:
2101
+ p = previous_terms[-2]
2102
+ return -p * ((n - 1)*(n-2)) * x**2/(4 * (n//2)**2)
2103
+ else:
2104
+ k = n // 2
2105
+ R = RisingFactorial(S.Half, k) * n
2106
+ F = factorial(k) * n // 2 * n // 2
2107
+ return S.NegativeOne**(k +1) * R / F * x**n / 4
2108
+
2109
+ def _eval_as_leading_term(self, x, logx=None, cdir=0): # acsch
2110
+ arg = self.args[0]
2111
+ x0 = arg.subs(x, 0).cancel()
2112
+ # Handling branch points
2113
+ if x0 in (-I, I, S.Zero):
2114
+ return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir)
2115
+ if x0 is S.ComplexInfinity:
2116
+ return (1/arg).as_leading_term(x)
2117
+ # Handling points lying on branch cuts (-I, I)
2118
+ if x0.is_imaginary and (1 + x0**2).is_positive:
2119
+ ndir = arg.dir(x, cdir if cdir else 1)
2120
+ if re(ndir).is_positive:
2121
+ if im(x0).is_positive:
2122
+ return -self.func(x0) - I*pi
2123
+ elif re(ndir).is_negative:
2124
+ if im(x0).is_negative:
2125
+ return -self.func(x0) + I*pi
2126
+ else:
2127
+ return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir)
2128
+ return self.func(x0)
2129
+
2130
+ def _eval_nseries(self, x, n, logx, cdir=0): # acsch
2131
+ from sympy.series.order import O
2132
+ arg = self.args[0]
2133
+ arg0 = arg.subs(x, 0)
2134
+
2135
+ # Handling branch points
2136
+ if arg0 is I:
2137
+ t = Dummy('t', positive=True)
2138
+ ser = acsch(I + t**2).rewrite(log).nseries(t, 0, 2*n)
2139
+ arg1 = -I + self.args[0]
2140
+ f = arg1.as_leading_term(x)
2141
+ g = (arg1 - f)/ f
2142
+ if not g.is_meromorphic(x, 0): # cannot be expanded
2143
+ return O(1) if n == 0 else -I*pi/2 + O(sqrt(x))
2144
+ res1 = sqrt(S.One + g)._eval_nseries(x, n=n, logx=logx)
2145
+ res = (res1.removeO()*sqrt(f)).expand()
2146
+ res = ser.removeO().subs(t, res).expand().powsimp() + O(x**n, x)
2147
+ return res
2148
+
2149
+ if arg0 == S.NegativeOne*I:
2150
+ t = Dummy('t', positive=True)
2151
+ ser = acsch(-I + t**2).rewrite(log).nseries(t, 0, 2*n)
2152
+ arg1 = I + self.args[0]
2153
+ f = arg1.as_leading_term(x)
2154
+ g = (arg1 - f)/ f
2155
+ if not g.is_meromorphic(x, 0): # cannot be expanded
2156
+ return O(1) if n == 0 else I*pi/2 + O(sqrt(x))
2157
+ res1 = sqrt(S.One + g)._eval_nseries(x, n=n, logx=logx)
2158
+ res = (res1.removeO()*sqrt(f)).expand()
2159
+ return ser.removeO().subs(t, res).expand().powsimp() + O(x**n, x)
2160
+
2161
+ res = Function._eval_nseries(self, x, n=n, logx=logx)
2162
+ if arg0 is S.ComplexInfinity:
2163
+ return res
2164
+
2165
+ # Handling points lying on branch cuts (-I, I)
2166
+ if arg0.is_imaginary and (1 + arg0**2).is_positive:
2167
+ ndir = self.args[0].dir(x, cdir if cdir else 1)
2168
+ if re(ndir).is_positive:
2169
+ if im(arg0).is_positive:
2170
+ return -res - I*pi
2171
+ elif re(ndir).is_negative:
2172
+ if im(arg0).is_negative:
2173
+ return -res + I*pi
2174
+ else:
2175
+ return self.rewrite(log)._eval_nseries(x, n, logx=logx, cdir=cdir)
2176
+ return res
2177
+
2178
+ def inverse(self, argindex=1):
2179
+ """
2180
+ Returns the inverse of this function.
2181
+ """
2182
+ return csch
2183
+
2184
+ def _eval_rewrite_as_log(self, arg, **kwargs):
2185
+ return log(1/arg + sqrt(1/arg**2 + 1))
2186
+
2187
+ _eval_rewrite_as_tractable = _eval_rewrite_as_log
2188
+
2189
+ def _eval_rewrite_as_asinh(self, arg, **kwargs):
2190
+ return asinh(1/arg)
2191
+
2192
+ def _eval_rewrite_as_acosh(self, arg, **kwargs):
2193
+ return I*(sqrt(1 - I/arg)/sqrt(I/arg - 1)*
2194
+ acosh(I/arg) - pi*S.Half)
2195
+
2196
+ def _eval_rewrite_as_atanh(self, arg, **kwargs):
2197
+ arg2 = arg**2
2198
+ arg2p1 = arg2 + 1
2199
+ return sqrt(-arg2)/arg*(pi*S.Half -
2200
+ sqrt(-arg2p1**2)/arg2p1*atanh(sqrt(arg2p1)))
2201
+
2202
+ def _eval_is_zero(self):
2203
+ return self.args[0].is_infinite
venv/lib/python3.10/site-packages/sympy/functions/elementary/integers.py ADDED
@@ -0,0 +1,625 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ from typing import Tuple as tTuple
2
+
3
+ from sympy.core.basic import Basic
4
+ from sympy.core.expr import Expr
5
+
6
+ from sympy.core import Add, S
7
+ from sympy.core.evalf import get_integer_part, PrecisionExhausted
8
+ from sympy.core.function import Function
9
+ from sympy.core.logic import fuzzy_or
10
+ from sympy.core.numbers import Integer
11
+ from sympy.core.relational import Gt, Lt, Ge, Le, Relational, is_eq
12
+ from sympy.core.symbol import Symbol
13
+ from sympy.core.sympify import _sympify
14
+ from sympy.functions.elementary.complexes import im, re
15
+ from sympy.multipledispatch import dispatch
16
+
17
+ ###############################################################################
18
+ ######################### FLOOR and CEILING FUNCTIONS #########################
19
+ ###############################################################################
20
+
21
+
22
+ class RoundFunction(Function):
23
+ """Abstract base class for rounding functions."""
24
+
25
+ args: tTuple[Expr]
26
+
27
+ @classmethod
28
+ def eval(cls, arg):
29
+ v = cls._eval_number(arg)
30
+ if v is not None:
31
+ return v
32
+
33
+ if arg.is_integer or arg.is_finite is False:
34
+ return arg
35
+ if arg.is_imaginary or (S.ImaginaryUnit*arg).is_real:
36
+ i = im(arg)
37
+ if not i.has(S.ImaginaryUnit):
38
+ return cls(i)*S.ImaginaryUnit
39
+ return cls(arg, evaluate=False)
40
+
41
+ # Integral, numerical, symbolic part
42
+ ipart = npart = spart = S.Zero
43
+
44
+ # Extract integral (or complex integral) terms
45
+ terms = Add.make_args(arg)
46
+
47
+ for t in terms:
48
+ if t.is_integer or (t.is_imaginary and im(t).is_integer):
49
+ ipart += t
50
+ elif t.has(Symbol):
51
+ spart += t
52
+ else:
53
+ npart += t
54
+
55
+ if not (npart or spart):
56
+ return ipart
57
+
58
+ # Evaluate npart numerically if independent of spart
59
+ if npart and (
60
+ not spart or
61
+ npart.is_real and (spart.is_imaginary or (S.ImaginaryUnit*spart).is_real) or
62
+ npart.is_imaginary and spart.is_real):
63
+ try:
64
+ r, i = get_integer_part(
65
+ npart, cls._dir, {}, return_ints=True)
66
+ ipart += Integer(r) + Integer(i)*S.ImaginaryUnit
67
+ npart = S.Zero
68
+ except (PrecisionExhausted, NotImplementedError):
69
+ pass
70
+
71
+ spart += npart
72
+ if not spart:
73
+ return ipart
74
+ elif spart.is_imaginary or (S.ImaginaryUnit*spart).is_real:
75
+ return ipart + cls(im(spart), evaluate=False)*S.ImaginaryUnit
76
+ elif isinstance(spart, (floor, ceiling)):
77
+ return ipart + spart
78
+ else:
79
+ return ipart + cls(spart, evaluate=False)
80
+
81
+ @classmethod
82
+ def _eval_number(cls, arg):
83
+ raise NotImplementedError()
84
+
85
+ def _eval_is_finite(self):
86
+ return self.args[0].is_finite
87
+
88
+ def _eval_is_real(self):
89
+ return self.args[0].is_real
90
+
91
+ def _eval_is_integer(self):
92
+ return self.args[0].is_real
93
+
94
+
95
+ class floor(RoundFunction):
96
+ """
97
+ Floor is a univariate function which returns the largest integer
98
+ value not greater than its argument. This implementation
99
+ generalizes floor to complex numbers by taking the floor of the
100
+ real and imaginary parts separately.
101
+
102
+ Examples
103
+ ========
104
+
105
+ >>> from sympy import floor, E, I, S, Float, Rational
106
+ >>> floor(17)
107
+ 17
108
+ >>> floor(Rational(23, 10))
109
+ 2
110
+ >>> floor(2*E)
111
+ 5
112
+ >>> floor(-Float(0.567))
113
+ -1
114
+ >>> floor(-I/2)
115
+ -I
116
+ >>> floor(S(5)/2 + 5*I/2)
117
+ 2 + 2*I
118
+
119
+ See Also
120
+ ========
121
+
122
+ sympy.functions.elementary.integers.ceiling
123
+
124
+ References
125
+ ==========
126
+
127
+ .. [1] "Concrete mathematics" by Graham, pp. 87
128
+ .. [2] https://mathworld.wolfram.com/FloorFunction.html
129
+
130
+ """
131
+ _dir = -1
132
+
133
+ @classmethod
134
+ def _eval_number(cls, arg):
135
+ if arg.is_Number:
136
+ return arg.floor()
137
+ elif any(isinstance(i, j)
138
+ for i in (arg, -arg) for j in (floor, ceiling)):
139
+ return arg
140
+ if arg.is_NumberSymbol:
141
+ return arg.approximation_interval(Integer)[0]
142
+
143
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
144
+ from sympy.calculus.accumulationbounds import AccumBounds
145
+ arg = self.args[0]
146
+ arg0 = arg.subs(x, 0)
147
+ r = self.subs(x, 0)
148
+ if arg0 is S.NaN or isinstance(arg0, AccumBounds):
149
+ arg0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
150
+ r = floor(arg0)
151
+ if arg0.is_finite:
152
+ if arg0 == r:
153
+ ndir = arg.dir(x, cdir=cdir)
154
+ return r - 1 if ndir.is_negative else r
155
+ else:
156
+ return r
157
+ return arg.as_leading_term(x, logx=logx, cdir=cdir)
158
+
159
+ def _eval_nseries(self, x, n, logx, cdir=0):
160
+ arg = self.args[0]
161
+ arg0 = arg.subs(x, 0)
162
+ r = self.subs(x, 0)
163
+ if arg0 is S.NaN:
164
+ arg0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
165
+ r = floor(arg0)
166
+ if arg0.is_infinite:
167
+ from sympy.calculus.accumulationbounds import AccumBounds
168
+ from sympy.series.order import Order
169
+ s = arg._eval_nseries(x, n, logx, cdir)
170
+ o = Order(1, (x, 0)) if n <= 0 else AccumBounds(-1, 0)
171
+ return s + o
172
+ if arg0 == r:
173
+ ndir = arg.dir(x, cdir=cdir if cdir != 0 else 1)
174
+ return r - 1 if ndir.is_negative else r
175
+ else:
176
+ return r
177
+
178
+ def _eval_is_negative(self):
179
+ return self.args[0].is_negative
180
+
181
+ def _eval_is_nonnegative(self):
182
+ return self.args[0].is_nonnegative
183
+
184
+ def _eval_rewrite_as_ceiling(self, arg, **kwargs):
185
+ return -ceiling(-arg)
186
+
187
+ def _eval_rewrite_as_frac(self, arg, **kwargs):
188
+ return arg - frac(arg)
189
+
190
+ def __le__(self, other):
191
+ other = S(other)
192
+ if self.args[0].is_real:
193
+ if other.is_integer:
194
+ return self.args[0] < other + 1
195
+ if other.is_number and other.is_real:
196
+ return self.args[0] < ceiling(other)
197
+ if self.args[0] == other and other.is_real:
198
+ return S.true
199
+ if other is S.Infinity and self.is_finite:
200
+ return S.true
201
+
202
+ return Le(self, other, evaluate=False)
203
+
204
+ def __ge__(self, other):
205
+ other = S(other)
206
+ if self.args[0].is_real:
207
+ if other.is_integer:
208
+ return self.args[0] >= other
209
+ if other.is_number and other.is_real:
210
+ return self.args[0] >= ceiling(other)
211
+ if self.args[0] == other and other.is_real:
212
+ return S.false
213
+ if other is S.NegativeInfinity and self.is_finite:
214
+ return S.true
215
+
216
+ return Ge(self, other, evaluate=False)
217
+
218
+ def __gt__(self, other):
219
+ other = S(other)
220
+ if self.args[0].is_real:
221
+ if other.is_integer:
222
+ return self.args[0] >= other + 1
223
+ if other.is_number and other.is_real:
224
+ return self.args[0] >= ceiling(other)
225
+ if self.args[0] == other and other.is_real:
226
+ return S.false
227
+ if other is S.NegativeInfinity and self.is_finite:
228
+ return S.true
229
+
230
+ return Gt(self, other, evaluate=False)
231
+
232
+ def __lt__(self, other):
233
+ other = S(other)
234
+ if self.args[0].is_real:
235
+ if other.is_integer:
236
+ return self.args[0] < other
237
+ if other.is_number and other.is_real:
238
+ return self.args[0] < ceiling(other)
239
+ if self.args[0] == other and other.is_real:
240
+ return S.false
241
+ if other is S.Infinity and self.is_finite:
242
+ return S.true
243
+
244
+ return Lt(self, other, evaluate=False)
245
+
246
+
247
+ @dispatch(floor, Expr)
248
+ def _eval_is_eq(lhs, rhs): # noqa:F811
249
+ return is_eq(lhs.rewrite(ceiling), rhs) or \
250
+ is_eq(lhs.rewrite(frac),rhs)
251
+
252
+
253
+ class ceiling(RoundFunction):
254
+ """
255
+ Ceiling is a univariate function which returns the smallest integer
256
+ value not less than its argument. This implementation
257
+ generalizes ceiling to complex numbers by taking the ceiling of the
258
+ real and imaginary parts separately.
259
+
260
+ Examples
261
+ ========
262
+
263
+ >>> from sympy import ceiling, E, I, S, Float, Rational
264
+ >>> ceiling(17)
265
+ 17
266
+ >>> ceiling(Rational(23, 10))
267
+ 3
268
+ >>> ceiling(2*E)
269
+ 6
270
+ >>> ceiling(-Float(0.567))
271
+ 0
272
+ >>> ceiling(I/2)
273
+ I
274
+ >>> ceiling(S(5)/2 + 5*I/2)
275
+ 3 + 3*I
276
+
277
+ See Also
278
+ ========
279
+
280
+ sympy.functions.elementary.integers.floor
281
+
282
+ References
283
+ ==========
284
+
285
+ .. [1] "Concrete mathematics" by Graham, pp. 87
286
+ .. [2] https://mathworld.wolfram.com/CeilingFunction.html
287
+
288
+ """
289
+ _dir = 1
290
+
291
+ @classmethod
292
+ def _eval_number(cls, arg):
293
+ if arg.is_Number:
294
+ return arg.ceiling()
295
+ elif any(isinstance(i, j)
296
+ for i in (arg, -arg) for j in (floor, ceiling)):
297
+ return arg
298
+ if arg.is_NumberSymbol:
299
+ return arg.approximation_interval(Integer)[1]
300
+
301
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
302
+ from sympy.calculus.accumulationbounds import AccumBounds
303
+ arg = self.args[0]
304
+ arg0 = arg.subs(x, 0)
305
+ r = self.subs(x, 0)
306
+ if arg0 is S.NaN or isinstance(arg0, AccumBounds):
307
+ arg0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
308
+ r = ceiling(arg0)
309
+ if arg0.is_finite:
310
+ if arg0 == r:
311
+ ndir = arg.dir(x, cdir=cdir)
312
+ return r if ndir.is_negative else r + 1
313
+ else:
314
+ return r
315
+ return arg.as_leading_term(x, logx=logx, cdir=cdir)
316
+
317
+ def _eval_nseries(self, x, n, logx, cdir=0):
318
+ arg = self.args[0]
319
+ arg0 = arg.subs(x, 0)
320
+ r = self.subs(x, 0)
321
+ if arg0 is S.NaN:
322
+ arg0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
323
+ r = ceiling(arg0)
324
+ if arg0.is_infinite:
325
+ from sympy.calculus.accumulationbounds import AccumBounds
326
+ from sympy.series.order import Order
327
+ s = arg._eval_nseries(x, n, logx, cdir)
328
+ o = Order(1, (x, 0)) if n <= 0 else AccumBounds(0, 1)
329
+ return s + o
330
+ if arg0 == r:
331
+ ndir = arg.dir(x, cdir=cdir if cdir != 0 else 1)
332
+ return r if ndir.is_negative else r + 1
333
+ else:
334
+ return r
335
+
336
+ def _eval_rewrite_as_floor(self, arg, **kwargs):
337
+ return -floor(-arg)
338
+
339
+ def _eval_rewrite_as_frac(self, arg, **kwargs):
340
+ return arg + frac(-arg)
341
+
342
+ def _eval_is_positive(self):
343
+ return self.args[0].is_positive
344
+
345
+ def _eval_is_nonpositive(self):
346
+ return self.args[0].is_nonpositive
347
+
348
+ def __lt__(self, other):
349
+ other = S(other)
350
+ if self.args[0].is_real:
351
+ if other.is_integer:
352
+ return self.args[0] <= other - 1
353
+ if other.is_number and other.is_real:
354
+ return self.args[0] <= floor(other)
355
+ if self.args[0] == other and other.is_real:
356
+ return S.false
357
+ if other is S.Infinity and self.is_finite:
358
+ return S.true
359
+
360
+ return Lt(self, other, evaluate=False)
361
+
362
+ def __gt__(self, other):
363
+ other = S(other)
364
+ if self.args[0].is_real:
365
+ if other.is_integer:
366
+ return self.args[0] > other
367
+ if other.is_number and other.is_real:
368
+ return self.args[0] > floor(other)
369
+ if self.args[0] == other and other.is_real:
370
+ return S.false
371
+ if other is S.NegativeInfinity and self.is_finite:
372
+ return S.true
373
+
374
+ return Gt(self, other, evaluate=False)
375
+
376
+ def __ge__(self, other):
377
+ other = S(other)
378
+ if self.args[0].is_real:
379
+ if other.is_integer:
380
+ return self.args[0] > other - 1
381
+ if other.is_number and other.is_real:
382
+ return self.args[0] > floor(other)
383
+ if self.args[0] == other and other.is_real:
384
+ return S.true
385
+ if other is S.NegativeInfinity and self.is_finite:
386
+ return S.true
387
+
388
+ return Ge(self, other, evaluate=False)
389
+
390
+ def __le__(self, other):
391
+ other = S(other)
392
+ if self.args[0].is_real:
393
+ if other.is_integer:
394
+ return self.args[0] <= other
395
+ if other.is_number and other.is_real:
396
+ return self.args[0] <= floor(other)
397
+ if self.args[0] == other and other.is_real:
398
+ return S.false
399
+ if other is S.Infinity and self.is_finite:
400
+ return S.true
401
+
402
+ return Le(self, other, evaluate=False)
403
+
404
+
405
+ @dispatch(ceiling, Basic) # type:ignore
406
+ def _eval_is_eq(lhs, rhs): # noqa:F811
407
+ return is_eq(lhs.rewrite(floor), rhs) or is_eq(lhs.rewrite(frac),rhs)
408
+
409
+
410
+ class frac(Function):
411
+ r"""Represents the fractional part of x
412
+
413
+ For real numbers it is defined [1]_ as
414
+
415
+ .. math::
416
+ x - \left\lfloor{x}\right\rfloor
417
+
418
+ Examples
419
+ ========
420
+
421
+ >>> from sympy import Symbol, frac, Rational, floor, I
422
+ >>> frac(Rational(4, 3))
423
+ 1/3
424
+ >>> frac(-Rational(4, 3))
425
+ 2/3
426
+
427
+ returns zero for integer arguments
428
+
429
+ >>> n = Symbol('n', integer=True)
430
+ >>> frac(n)
431
+ 0
432
+
433
+ rewrite as floor
434
+
435
+ >>> x = Symbol('x')
436
+ >>> frac(x).rewrite(floor)
437
+ x - floor(x)
438
+
439
+ for complex arguments
440
+
441
+ >>> r = Symbol('r', real=True)
442
+ >>> t = Symbol('t', real=True)
443
+ >>> frac(t + I*r)
444
+ I*frac(r) + frac(t)
445
+
446
+ See Also
447
+ ========
448
+
449
+ sympy.functions.elementary.integers.floor
450
+ sympy.functions.elementary.integers.ceiling
451
+
452
+ References
453
+ ===========
454
+
455
+ .. [1] https://en.wikipedia.org/wiki/Fractional_part
456
+ .. [2] https://mathworld.wolfram.com/FractionalPart.html
457
+
458
+ """
459
+ @classmethod
460
+ def eval(cls, arg):
461
+ from sympy.calculus.accumulationbounds import AccumBounds
462
+
463
+ def _eval(arg):
464
+ if arg in (S.Infinity, S.NegativeInfinity):
465
+ return AccumBounds(0, 1)
466
+ if arg.is_integer:
467
+ return S.Zero
468
+ if arg.is_number:
469
+ if arg is S.NaN:
470
+ return S.NaN
471
+ elif arg is S.ComplexInfinity:
472
+ return S.NaN
473
+ else:
474
+ return arg - floor(arg)
475
+ return cls(arg, evaluate=False)
476
+
477
+ terms = Add.make_args(arg)
478
+ real, imag = S.Zero, S.Zero
479
+ for t in terms:
480
+ # Two checks are needed for complex arguments
481
+ # see issue-7649 for details
482
+ if t.is_imaginary or (S.ImaginaryUnit*t).is_real:
483
+ i = im(t)
484
+ if not i.has(S.ImaginaryUnit):
485
+ imag += i
486
+ else:
487
+ real += t
488
+ else:
489
+ real += t
490
+
491
+ real = _eval(real)
492
+ imag = _eval(imag)
493
+ return real + S.ImaginaryUnit*imag
494
+
495
+ def _eval_rewrite_as_floor(self, arg, **kwargs):
496
+ return arg - floor(arg)
497
+
498
+ def _eval_rewrite_as_ceiling(self, arg, **kwargs):
499
+ return arg + ceiling(-arg)
500
+
501
+ def _eval_is_finite(self):
502
+ return True
503
+
504
+ def _eval_is_real(self):
505
+ return self.args[0].is_extended_real
506
+
507
+ def _eval_is_imaginary(self):
508
+ return self.args[0].is_imaginary
509
+
510
+ def _eval_is_integer(self):
511
+ return self.args[0].is_integer
512
+
513
+ def _eval_is_zero(self):
514
+ return fuzzy_or([self.args[0].is_zero, self.args[0].is_integer])
515
+
516
+ def _eval_is_negative(self):
517
+ return False
518
+
519
+ def __ge__(self, other):
520
+ if self.is_extended_real:
521
+ other = _sympify(other)
522
+ # Check if other <= 0
523
+ if other.is_extended_nonpositive:
524
+ return S.true
525
+ # Check if other >= 1
526
+ res = self._value_one_or_more(other)
527
+ if res is not None:
528
+ return not(res)
529
+ return Ge(self, other, evaluate=False)
530
+
531
+ def __gt__(self, other):
532
+ if self.is_extended_real:
533
+ other = _sympify(other)
534
+ # Check if other < 0
535
+ res = self._value_one_or_more(other)
536
+ if res is not None:
537
+ return not(res)
538
+ # Check if other >= 1
539
+ if other.is_extended_negative:
540
+ return S.true
541
+ return Gt(self, other, evaluate=False)
542
+
543
+ def __le__(self, other):
544
+ if self.is_extended_real:
545
+ other = _sympify(other)
546
+ # Check if other < 0
547
+ if other.is_extended_negative:
548
+ return S.false
549
+ # Check if other >= 1
550
+ res = self._value_one_or_more(other)
551
+ if res is not None:
552
+ return res
553
+ return Le(self, other, evaluate=False)
554
+
555
+ def __lt__(self, other):
556
+ if self.is_extended_real:
557
+ other = _sympify(other)
558
+ # Check if other <= 0
559
+ if other.is_extended_nonpositive:
560
+ return S.false
561
+ # Check if other >= 1
562
+ res = self._value_one_or_more(other)
563
+ if res is not None:
564
+ return res
565
+ return Lt(self, other, evaluate=False)
566
+
567
+ def _value_one_or_more(self, other):
568
+ if other.is_extended_real:
569
+ if other.is_number:
570
+ res = other >= 1
571
+ if res and not isinstance(res, Relational):
572
+ return S.true
573
+ if other.is_integer and other.is_positive:
574
+ return S.true
575
+
576
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
577
+ from sympy.calculus.accumulationbounds import AccumBounds
578
+ arg = self.args[0]
579
+ arg0 = arg.subs(x, 0)
580
+ r = self.subs(x, 0)
581
+
582
+ if arg0.is_finite:
583
+ if r.is_zero:
584
+ ndir = arg.dir(x, cdir=cdir)
585
+ if ndir.is_negative:
586
+ return S.One
587
+ return (arg - arg0).as_leading_term(x, logx=logx, cdir=cdir)
588
+ else:
589
+ return r
590
+ elif arg0 in (S.ComplexInfinity, S.Infinity, S.NegativeInfinity):
591
+ return AccumBounds(0, 1)
592
+ return arg.as_leading_term(x, logx=logx, cdir=cdir)
593
+
594
+ def _eval_nseries(self, x, n, logx, cdir=0):
595
+ from sympy.series.order import Order
596
+ arg = self.args[0]
597
+ arg0 = arg.subs(x, 0)
598
+ r = self.subs(x, 0)
599
+
600
+ if arg0.is_infinite:
601
+ from sympy.calculus.accumulationbounds import AccumBounds
602
+ o = Order(1, (x, 0)) if n <= 0 else AccumBounds(0, 1) + Order(x**n, (x, 0))
603
+ return o
604
+ else:
605
+ res = (arg - arg0)._eval_nseries(x, n, logx=logx, cdir=cdir)
606
+ if r.is_zero:
607
+ ndir = arg.dir(x, cdir=cdir)
608
+ res += S.One if ndir.is_negative else S.Zero
609
+ else:
610
+ res += r
611
+ return res
612
+
613
+
614
+ @dispatch(frac, Basic) # type:ignore
615
+ def _eval_is_eq(lhs, rhs): # noqa:F811
616
+ if (lhs.rewrite(floor) == rhs) or \
617
+ (lhs.rewrite(ceiling) == rhs):
618
+ return True
619
+ # Check if other < 0
620
+ if rhs.is_extended_negative:
621
+ return False
622
+ # Check if other >= 1
623
+ res = lhs._value_one_or_more(rhs)
624
+ if res is not None:
625
+ return False
venv/lib/python3.10/site-packages/sympy/functions/elementary/miscellaneous.py ADDED
@@ -0,0 +1,915 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ from sympy.core import Function, S, sympify, NumberKind
2
+ from sympy.utilities.iterables import sift
3
+ from sympy.core.add import Add
4
+ from sympy.core.containers import Tuple
5
+ from sympy.core.operations import LatticeOp, ShortCircuit
6
+ from sympy.core.function import (Application, Lambda,
7
+ ArgumentIndexError)
8
+ from sympy.core.expr import Expr
9
+ from sympy.core.exprtools import factor_terms
10
+ from sympy.core.mod import Mod
11
+ from sympy.core.mul import Mul
12
+ from sympy.core.numbers import Rational
13
+ from sympy.core.power import Pow
14
+ from sympy.core.relational import Eq, Relational
15
+ from sympy.core.singleton import Singleton
16
+ from sympy.core.sorting import ordered
17
+ from sympy.core.symbol import Dummy
18
+ from sympy.core.rules import Transform
19
+ from sympy.core.logic import fuzzy_and, fuzzy_or, _torf
20
+ from sympy.core.traversal import walk
21
+ from sympy.core.numbers import Integer
22
+ from sympy.logic.boolalg import And, Or
23
+
24
+
25
+ def _minmax_as_Piecewise(op, *args):
26
+ # helper for Min/Max rewrite as Piecewise
27
+ from sympy.functions.elementary.piecewise import Piecewise
28
+ ec = []
29
+ for i, a in enumerate(args):
30
+ c = [Relational(a, args[j], op) for j in range(i + 1, len(args))]
31
+ ec.append((a, And(*c)))
32
+ return Piecewise(*ec)
33
+
34
+
35
+ class IdentityFunction(Lambda, metaclass=Singleton):
36
+ """
37
+ The identity function
38
+
39
+ Examples
40
+ ========
41
+
42
+ >>> from sympy import Id, Symbol
43
+ >>> x = Symbol('x')
44
+ >>> Id(x)
45
+ x
46
+
47
+ """
48
+
49
+ _symbol = Dummy('x')
50
+
51
+ @property
52
+ def signature(self):
53
+ return Tuple(self._symbol)
54
+
55
+ @property
56
+ def expr(self):
57
+ return self._symbol
58
+
59
+
60
+ Id = S.IdentityFunction
61
+
62
+ ###############################################################################
63
+ ############################# ROOT and SQUARE ROOT FUNCTION ###################
64
+ ###############################################################################
65
+
66
+
67
+ def sqrt(arg, evaluate=None):
68
+ """Returns the principal square root.
69
+
70
+ Parameters
71
+ ==========
72
+
73
+ evaluate : bool, optional
74
+ The parameter determines if the expression should be evaluated.
75
+ If ``None``, its value is taken from
76
+ ``global_parameters.evaluate``.
77
+
78
+ Examples
79
+ ========
80
+
81
+ >>> from sympy import sqrt, Symbol, S
82
+ >>> x = Symbol('x')
83
+
84
+ >>> sqrt(x)
85
+ sqrt(x)
86
+
87
+ >>> sqrt(x)**2
88
+ x
89
+
90
+ Note that sqrt(x**2) does not simplify to x.
91
+
92
+ >>> sqrt(x**2)
93
+ sqrt(x**2)
94
+
95
+ This is because the two are not equal to each other in general.
96
+ For example, consider x == -1:
97
+
98
+ >>> from sympy import Eq
99
+ >>> Eq(sqrt(x**2), x).subs(x, -1)
100
+ False
101
+
102
+ This is because sqrt computes the principal square root, so the square may
103
+ put the argument in a different branch. This identity does hold if x is
104
+ positive:
105
+
106
+ >>> y = Symbol('y', positive=True)
107
+ >>> sqrt(y**2)
108
+ y
109
+
110
+ You can force this simplification by using the powdenest() function with
111
+ the force option set to True:
112
+
113
+ >>> from sympy import powdenest
114
+ >>> sqrt(x**2)
115
+ sqrt(x**2)
116
+ >>> powdenest(sqrt(x**2), force=True)
117
+ x
118
+
119
+ To get both branches of the square root you can use the rootof function:
120
+
121
+ >>> from sympy import rootof
122
+
123
+ >>> [rootof(x**2-3,i) for i in (0,1)]
124
+ [-sqrt(3), sqrt(3)]
125
+
126
+ Although ``sqrt`` is printed, there is no ``sqrt`` function so looking for
127
+ ``sqrt`` in an expression will fail:
128
+
129
+ >>> from sympy.utilities.misc import func_name
130
+ >>> func_name(sqrt(x))
131
+ 'Pow'
132
+ >>> sqrt(x).has(sqrt)
133
+ False
134
+
135
+ To find ``sqrt`` look for ``Pow`` with an exponent of ``1/2``:
136
+
137
+ >>> (x + 1/sqrt(x)).find(lambda i: i.is_Pow and abs(i.exp) is S.Half)
138
+ {1/sqrt(x)}
139
+
140
+ See Also
141
+ ========
142
+
143
+ sympy.polys.rootoftools.rootof, root, real_root
144
+
145
+ References
146
+ ==========
147
+
148
+ .. [1] https://en.wikipedia.org/wiki/Square_root
149
+ .. [2] https://en.wikipedia.org/wiki/Principal_value
150
+ """
151
+ # arg = sympify(arg) is handled by Pow
152
+ return Pow(arg, S.Half, evaluate=evaluate)
153
+
154
+
155
+ def cbrt(arg, evaluate=None):
156
+ """Returns the principal cube root.
157
+
158
+ Parameters
159
+ ==========
160
+
161
+ evaluate : bool, optional
162
+ The parameter determines if the expression should be evaluated.
163
+ If ``None``, its value is taken from
164
+ ``global_parameters.evaluate``.
165
+
166
+ Examples
167
+ ========
168
+
169
+ >>> from sympy import cbrt, Symbol
170
+ >>> x = Symbol('x')
171
+
172
+ >>> cbrt(x)
173
+ x**(1/3)
174
+
175
+ >>> cbrt(x)**3
176
+ x
177
+
178
+ Note that cbrt(x**3) does not simplify to x.
179
+
180
+ >>> cbrt(x**3)
181
+ (x**3)**(1/3)
182
+
183
+ This is because the two are not equal to each other in general.
184
+ For example, consider `x == -1`:
185
+
186
+ >>> from sympy import Eq
187
+ >>> Eq(cbrt(x**3), x).subs(x, -1)
188
+ False
189
+
190
+ This is because cbrt computes the principal cube root, this
191
+ identity does hold if `x` is positive:
192
+
193
+ >>> y = Symbol('y', positive=True)
194
+ >>> cbrt(y**3)
195
+ y
196
+
197
+ See Also
198
+ ========
199
+
200
+ sympy.polys.rootoftools.rootof, root, real_root
201
+
202
+ References
203
+ ==========
204
+
205
+ .. [1] https://en.wikipedia.org/wiki/Cube_root
206
+ .. [2] https://en.wikipedia.org/wiki/Principal_value
207
+
208
+ """
209
+ return Pow(arg, Rational(1, 3), evaluate=evaluate)
210
+
211
+
212
+ def root(arg, n, k=0, evaluate=None):
213
+ r"""Returns the *k*-th *n*-th root of ``arg``.
214
+
215
+ Parameters
216
+ ==========
217
+
218
+ k : int, optional
219
+ Should be an integer in $\{0, 1, ..., n-1\}$.
220
+ Defaults to the principal root if $0$.
221
+
222
+ evaluate : bool, optional
223
+ The parameter determines if the expression should be evaluated.
224
+ If ``None``, its value is taken from
225
+ ``global_parameters.evaluate``.
226
+
227
+ Examples
228
+ ========
229
+
230
+ >>> from sympy import root, Rational
231
+ >>> from sympy.abc import x, n
232
+
233
+ >>> root(x, 2)
234
+ sqrt(x)
235
+
236
+ >>> root(x, 3)
237
+ x**(1/3)
238
+
239
+ >>> root(x, n)
240
+ x**(1/n)
241
+
242
+ >>> root(x, -Rational(2, 3))
243
+ x**(-3/2)
244
+
245
+ To get the k-th n-th root, specify k:
246
+
247
+ >>> root(-2, 3, 2)
248
+ -(-1)**(2/3)*2**(1/3)
249
+
250
+ To get all n n-th roots you can use the rootof function.
251
+ The following examples show the roots of unity for n
252
+ equal 2, 3 and 4:
253
+
254
+ >>> from sympy import rootof
255
+
256
+ >>> [rootof(x**2 - 1, i) for i in range(2)]
257
+ [-1, 1]
258
+
259
+ >>> [rootof(x**3 - 1,i) for i in range(3)]
260
+ [1, -1/2 - sqrt(3)*I/2, -1/2 + sqrt(3)*I/2]
261
+
262
+ >>> [rootof(x**4 - 1,i) for i in range(4)]
263
+ [-1, 1, -I, I]
264
+
265
+ SymPy, like other symbolic algebra systems, returns the
266
+ complex root of negative numbers. This is the principal
267
+ root and differs from the text-book result that one might
268
+ be expecting. For example, the cube root of -8 does not
269
+ come back as -2:
270
+
271
+ >>> root(-8, 3)
272
+ 2*(-1)**(1/3)
273
+
274
+ The real_root function can be used to either make the principal
275
+ result real (or simply to return the real root directly):
276
+
277
+ >>> from sympy import real_root
278
+ >>> real_root(_)
279
+ -2
280
+ >>> real_root(-32, 5)
281
+ -2
282
+
283
+ Alternatively, the n//2-th n-th root of a negative number can be
284
+ computed with root:
285
+
286
+ >>> root(-32, 5, 5//2)
287
+ -2
288
+
289
+ See Also
290
+ ========
291
+
292
+ sympy.polys.rootoftools.rootof
293
+ sympy.core.power.integer_nthroot
294
+ sqrt, real_root
295
+
296
+ References
297
+ ==========
298
+
299
+ .. [1] https://en.wikipedia.org/wiki/Square_root
300
+ .. [2] https://en.wikipedia.org/wiki/Real_root
301
+ .. [3] https://en.wikipedia.org/wiki/Root_of_unity
302
+ .. [4] https://en.wikipedia.org/wiki/Principal_value
303
+ .. [5] https://mathworld.wolfram.com/CubeRoot.html
304
+
305
+ """
306
+ n = sympify(n)
307
+ if k:
308
+ return Mul(Pow(arg, S.One/n, evaluate=evaluate), S.NegativeOne**(2*k/n), evaluate=evaluate)
309
+ return Pow(arg, 1/n, evaluate=evaluate)
310
+
311
+
312
+ def real_root(arg, n=None, evaluate=None):
313
+ r"""Return the real *n*'th-root of *arg* if possible.
314
+
315
+ Parameters
316
+ ==========
317
+
318
+ n : int or None, optional
319
+ If *n* is ``None``, then all instances of
320
+ $(-n)^{1/\text{odd}}$ will be changed to $-n^{1/\text{odd}}$.
321
+ This will only create a real root of a principal root.
322
+ The presence of other factors may cause the result to not be
323
+ real.
324
+
325
+ evaluate : bool, optional
326
+ The parameter determines if the expression should be evaluated.
327
+ If ``None``, its value is taken from
328
+ ``global_parameters.evaluate``.
329
+
330
+ Examples
331
+ ========
332
+
333
+ >>> from sympy import root, real_root
334
+
335
+ >>> real_root(-8, 3)
336
+ -2
337
+ >>> root(-8, 3)
338
+ 2*(-1)**(1/3)
339
+ >>> real_root(_)
340
+ -2
341
+
342
+ If one creates a non-principal root and applies real_root, the
343
+ result will not be real (so use with caution):
344
+
345
+ >>> root(-8, 3, 2)
346
+ -2*(-1)**(2/3)
347
+ >>> real_root(_)
348
+ -2*(-1)**(2/3)
349
+
350
+ See Also
351
+ ========
352
+
353
+ sympy.polys.rootoftools.rootof
354
+ sympy.core.power.integer_nthroot
355
+ root, sqrt
356
+ """
357
+ from sympy.functions.elementary.complexes import Abs, im, sign
358
+ from sympy.functions.elementary.piecewise import Piecewise
359
+ if n is not None:
360
+ return Piecewise(
361
+ (root(arg, n, evaluate=evaluate), Or(Eq(n, S.One), Eq(n, S.NegativeOne))),
362
+ (Mul(sign(arg), root(Abs(arg), n, evaluate=evaluate), evaluate=evaluate),
363
+ And(Eq(im(arg), S.Zero), Eq(Mod(n, 2), S.One))),
364
+ (root(arg, n, evaluate=evaluate), True))
365
+ rv = sympify(arg)
366
+ n1pow = Transform(lambda x: -(-x.base)**x.exp,
367
+ lambda x:
368
+ x.is_Pow and
369
+ x.base.is_negative and
370
+ x.exp.is_Rational and
371
+ x.exp.p == 1 and x.exp.q % 2)
372
+ return rv.xreplace(n1pow)
373
+
374
+ ###############################################################################
375
+ ############################# MINIMUM and MAXIMUM #############################
376
+ ###############################################################################
377
+
378
+
379
+ class MinMaxBase(Expr, LatticeOp):
380
+ def __new__(cls, *args, **assumptions):
381
+ from sympy.core.parameters import global_parameters
382
+ evaluate = assumptions.pop('evaluate', global_parameters.evaluate)
383
+ args = (sympify(arg) for arg in args)
384
+
385
+ # first standard filter, for cls.zero and cls.identity
386
+ # also reshape Max(a, Max(b, c)) to Max(a, b, c)
387
+
388
+ if evaluate:
389
+ try:
390
+ args = frozenset(cls._new_args_filter(args))
391
+ except ShortCircuit:
392
+ return cls.zero
393
+ # remove redundant args that are easily identified
394
+ args = cls._collapse_arguments(args, **assumptions)
395
+ # find local zeros
396
+ args = cls._find_localzeros(args, **assumptions)
397
+ args = frozenset(args)
398
+
399
+ if not args:
400
+ return cls.identity
401
+
402
+ if len(args) == 1:
403
+ return list(args).pop()
404
+
405
+ # base creation
406
+ obj = Expr.__new__(cls, *ordered(args), **assumptions)
407
+ obj._argset = args
408
+ return obj
409
+
410
+ @classmethod
411
+ def _collapse_arguments(cls, args, **assumptions):
412
+ """Remove redundant args.
413
+
414
+ Examples
415
+ ========
416
+
417
+ >>> from sympy import Min, Max
418
+ >>> from sympy.abc import a, b, c, d, e
419
+
420
+ Any arg in parent that appears in any
421
+ parent-like function in any of the flat args
422
+ of parent can be removed from that sub-arg:
423
+
424
+ >>> Min(a, Max(b, Min(a, c, d)))
425
+ Min(a, Max(b, Min(c, d)))
426
+
427
+ If the arg of parent appears in an opposite-than parent
428
+ function in any of the flat args of parent that function
429
+ can be replaced with the arg:
430
+
431
+ >>> Min(a, Max(b, Min(c, d, Max(a, e))))
432
+ Min(a, Max(b, Min(a, c, d)))
433
+ """
434
+ if not args:
435
+ return args
436
+ args = list(ordered(args))
437
+ if cls == Min:
438
+ other = Max
439
+ else:
440
+ other = Min
441
+
442
+ # find global comparable max of Max and min of Min if a new
443
+ # value is being introduced in these args at position 0 of
444
+ # the ordered args
445
+ if args[0].is_number:
446
+ sifted = mins, maxs = [], []
447
+ for i in args:
448
+ for v in walk(i, Min, Max):
449
+ if v.args[0].is_comparable:
450
+ sifted[isinstance(v, Max)].append(v)
451
+ small = Min.identity
452
+ for i in mins:
453
+ v = i.args[0]
454
+ if v.is_number and (v < small) == True:
455
+ small = v
456
+ big = Max.identity
457
+ for i in maxs:
458
+ v = i.args[0]
459
+ if v.is_number and (v > big) == True:
460
+ big = v
461
+ # at the point when this function is called from __new__,
462
+ # there may be more than one numeric arg present since
463
+ # local zeros have not been handled yet, so look through
464
+ # more than the first arg
465
+ if cls == Min:
466
+ for arg in args:
467
+ if not arg.is_number:
468
+ break
469
+ if (arg < small) == True:
470
+ small = arg
471
+ elif cls == Max:
472
+ for arg in args:
473
+ if not arg.is_number:
474
+ break
475
+ if (arg > big) == True:
476
+ big = arg
477
+ T = None
478
+ if cls == Min:
479
+ if small != Min.identity:
480
+ other = Max
481
+ T = small
482
+ elif big != Max.identity:
483
+ other = Min
484
+ T = big
485
+ if T is not None:
486
+ # remove numerical redundancy
487
+ for i in range(len(args)):
488
+ a = args[i]
489
+ if isinstance(a, other):
490
+ a0 = a.args[0]
491
+ if ((a0 > T) if other == Max else (a0 < T)) == True:
492
+ args[i] = cls.identity
493
+
494
+ # remove redundant symbolic args
495
+ def do(ai, a):
496
+ if not isinstance(ai, (Min, Max)):
497
+ return ai
498
+ cond = a in ai.args
499
+ if not cond:
500
+ return ai.func(*[do(i, a) for i in ai.args],
501
+ evaluate=False)
502
+ if isinstance(ai, cls):
503
+ return ai.func(*[do(i, a) for i in ai.args if i != a],
504
+ evaluate=False)
505
+ return a
506
+ for i, a in enumerate(args):
507
+ args[i + 1:] = [do(ai, a) for ai in args[i + 1:]]
508
+
509
+ # factor out common elements as for
510
+ # Min(Max(x, y), Max(x, z)) -> Max(x, Min(y, z))
511
+ # and vice versa when swapping Min/Max -- do this only for the
512
+ # easy case where all functions contain something in common;
513
+ # trying to find some optimal subset of args to modify takes
514
+ # too long
515
+
516
+ def factor_minmax(args):
517
+ is_other = lambda arg: isinstance(arg, other)
518
+ other_args, remaining_args = sift(args, is_other, binary=True)
519
+ if not other_args:
520
+ return args
521
+
522
+ # Min(Max(x, y, z), Max(x, y, u, v)) -> {x,y}, ({z}, {u,v})
523
+ arg_sets = [set(arg.args) for arg in other_args]
524
+ common = set.intersection(*arg_sets)
525
+ if not common:
526
+ return args
527
+
528
+ new_other_args = list(common)
529
+ arg_sets_diff = [arg_set - common for arg_set in arg_sets]
530
+
531
+ # If any set is empty after removing common then all can be
532
+ # discarded e.g. Min(Max(a, b, c), Max(a, b)) -> Max(a, b)
533
+ if all(arg_sets_diff):
534
+ other_args_diff = [other(*s, evaluate=False) for s in arg_sets_diff]
535
+ new_other_args.append(cls(*other_args_diff, evaluate=False))
536
+
537
+ other_args_factored = other(*new_other_args, evaluate=False)
538
+ return remaining_args + [other_args_factored]
539
+
540
+ if len(args) > 1:
541
+ args = factor_minmax(args)
542
+
543
+ return args
544
+
545
+ @classmethod
546
+ def _new_args_filter(cls, arg_sequence):
547
+ """
548
+ Generator filtering args.
549
+
550
+ first standard filter, for cls.zero and cls.identity.
551
+ Also reshape ``Max(a, Max(b, c))`` to ``Max(a, b, c)``,
552
+ and check arguments for comparability
553
+ """
554
+ for arg in arg_sequence:
555
+ # pre-filter, checking comparability of arguments
556
+ if not isinstance(arg, Expr) or arg.is_extended_real is False or (
557
+ arg.is_number and
558
+ not arg.is_comparable):
559
+ raise ValueError("The argument '%s' is not comparable." % arg)
560
+
561
+ if arg == cls.zero:
562
+ raise ShortCircuit(arg)
563
+ elif arg == cls.identity:
564
+ continue
565
+ elif arg.func == cls:
566
+ yield from arg.args
567
+ else:
568
+ yield arg
569
+
570
+ @classmethod
571
+ def _find_localzeros(cls, values, **options):
572
+ """
573
+ Sequentially allocate values to localzeros.
574
+
575
+ When a value is identified as being more extreme than another member it
576
+ replaces that member; if this is never true, then the value is simply
577
+ appended to the localzeros.
578
+ """
579
+ localzeros = set()
580
+ for v in values:
581
+ is_newzero = True
582
+ localzeros_ = list(localzeros)
583
+ for z in localzeros_:
584
+ if id(v) == id(z):
585
+ is_newzero = False
586
+ else:
587
+ con = cls._is_connected(v, z)
588
+ if con:
589
+ is_newzero = False
590
+ if con is True or con == cls:
591
+ localzeros.remove(z)
592
+ localzeros.update([v])
593
+ if is_newzero:
594
+ localzeros.update([v])
595
+ return localzeros
596
+
597
+ @classmethod
598
+ def _is_connected(cls, x, y):
599
+ """
600
+ Check if x and y are connected somehow.
601
+ """
602
+ for i in range(2):
603
+ if x == y:
604
+ return True
605
+ t, f = Max, Min
606
+ for op in "><":
607
+ for j in range(2):
608
+ try:
609
+ if op == ">":
610
+ v = x >= y
611
+ else:
612
+ v = x <= y
613
+ except TypeError:
614
+ return False # non-real arg
615
+ if not v.is_Relational:
616
+ return t if v else f
617
+ t, f = f, t
618
+ x, y = y, x
619
+ x, y = y, x # run next pass with reversed order relative to start
620
+ # simplification can be expensive, so be conservative
621
+ # in what is attempted
622
+ x = factor_terms(x - y)
623
+ y = S.Zero
624
+
625
+ return False
626
+
627
+ def _eval_derivative(self, s):
628
+ # f(x).diff(s) -> x.diff(s) * f.fdiff(1)(s)
629
+ i = 0
630
+ l = []
631
+ for a in self.args:
632
+ i += 1
633
+ da = a.diff(s)
634
+ if da.is_zero:
635
+ continue
636
+ try:
637
+ df = self.fdiff(i)
638
+ except ArgumentIndexError:
639
+ df = Function.fdiff(self, i)
640
+ l.append(df * da)
641
+ return Add(*l)
642
+
643
+ def _eval_rewrite_as_Abs(self, *args, **kwargs):
644
+ from sympy.functions.elementary.complexes import Abs
645
+ s = (args[0] + self.func(*args[1:]))/2
646
+ d = abs(args[0] - self.func(*args[1:]))/2
647
+ return (s + d if isinstance(self, Max) else s - d).rewrite(Abs)
648
+
649
+ def evalf(self, n=15, **options):
650
+ return self.func(*[a.evalf(n, **options) for a in self.args])
651
+
652
+ def n(self, *args, **kwargs):
653
+ return self.evalf(*args, **kwargs)
654
+
655
+ _eval_is_algebraic = lambda s: _torf(i.is_algebraic for i in s.args)
656
+ _eval_is_antihermitian = lambda s: _torf(i.is_antihermitian for i in s.args)
657
+ _eval_is_commutative = lambda s: _torf(i.is_commutative for i in s.args)
658
+ _eval_is_complex = lambda s: _torf(i.is_complex for i in s.args)
659
+ _eval_is_composite = lambda s: _torf(i.is_composite for i in s.args)
660
+ _eval_is_even = lambda s: _torf(i.is_even for i in s.args)
661
+ _eval_is_finite = lambda s: _torf(i.is_finite for i in s.args)
662
+ _eval_is_hermitian = lambda s: _torf(i.is_hermitian for i in s.args)
663
+ _eval_is_imaginary = lambda s: _torf(i.is_imaginary for i in s.args)
664
+ _eval_is_infinite = lambda s: _torf(i.is_infinite for i in s.args)
665
+ _eval_is_integer = lambda s: _torf(i.is_integer for i in s.args)
666
+ _eval_is_irrational = lambda s: _torf(i.is_irrational for i in s.args)
667
+ _eval_is_negative = lambda s: _torf(i.is_negative for i in s.args)
668
+ _eval_is_noninteger = lambda s: _torf(i.is_noninteger for i in s.args)
669
+ _eval_is_nonnegative = lambda s: _torf(i.is_nonnegative for i in s.args)
670
+ _eval_is_nonpositive = lambda s: _torf(i.is_nonpositive for i in s.args)
671
+ _eval_is_nonzero = lambda s: _torf(i.is_nonzero for i in s.args)
672
+ _eval_is_odd = lambda s: _torf(i.is_odd for i in s.args)
673
+ _eval_is_polar = lambda s: _torf(i.is_polar for i in s.args)
674
+ _eval_is_positive = lambda s: _torf(i.is_positive for i in s.args)
675
+ _eval_is_prime = lambda s: _torf(i.is_prime for i in s.args)
676
+ _eval_is_rational = lambda s: _torf(i.is_rational for i in s.args)
677
+ _eval_is_real = lambda s: _torf(i.is_real for i in s.args)
678
+ _eval_is_extended_real = lambda s: _torf(i.is_extended_real for i in s.args)
679
+ _eval_is_transcendental = lambda s: _torf(i.is_transcendental for i in s.args)
680
+ _eval_is_zero = lambda s: _torf(i.is_zero for i in s.args)
681
+
682
+
683
+ class Max(MinMaxBase, Application):
684
+ r"""
685
+ Return, if possible, the maximum value of the list.
686
+
687
+ When number of arguments is equal one, then
688
+ return this argument.
689
+
690
+ When number of arguments is equal two, then
691
+ return, if possible, the value from (a, b) that is $\ge$ the other.
692
+
693
+ In common case, when the length of list greater than 2, the task
694
+ is more complicated. Return only the arguments, which are greater
695
+ than others, if it is possible to determine directional relation.
696
+
697
+ If is not possible to determine such a relation, return a partially
698
+ evaluated result.
699
+
700
+ Assumptions are used to make the decision too.
701
+
702
+ Also, only comparable arguments are permitted.
703
+
704
+ It is named ``Max`` and not ``max`` to avoid conflicts
705
+ with the built-in function ``max``.
706
+
707
+
708
+ Examples
709
+ ========
710
+
711
+ >>> from sympy import Max, Symbol, oo
712
+ >>> from sympy.abc import x, y, z
713
+ >>> p = Symbol('p', positive=True)
714
+ >>> n = Symbol('n', negative=True)
715
+
716
+ >>> Max(x, -2)
717
+ Max(-2, x)
718
+ >>> Max(x, -2).subs(x, 3)
719
+ 3
720
+ >>> Max(p, -2)
721
+ p
722
+ >>> Max(x, y)
723
+ Max(x, y)
724
+ >>> Max(x, y) == Max(y, x)
725
+ True
726
+ >>> Max(x, Max(y, z))
727
+ Max(x, y, z)
728
+ >>> Max(n, 8, p, 7, -oo)
729
+ Max(8, p)
730
+ >>> Max (1, x, oo)
731
+ oo
732
+
733
+ * Algorithm
734
+
735
+ The task can be considered as searching of supremums in the
736
+ directed complete partial orders [1]_.
737
+
738
+ The source values are sequentially allocated by the isolated subsets
739
+ in which supremums are searched and result as Max arguments.
740
+
741
+ If the resulted supremum is single, then it is returned.
742
+
743
+ The isolated subsets are the sets of values which are only the comparable
744
+ with each other in the current set. E.g. natural numbers are comparable with
745
+ each other, but not comparable with the `x` symbol. Another example: the
746
+ symbol `x` with negative assumption is comparable with a natural number.
747
+
748
+ Also there are "least" elements, which are comparable with all others,
749
+ and have a zero property (maximum or minimum for all elements).
750
+ For example, in case of $\infty$, the allocation operation is terminated
751
+ and only this value is returned.
752
+
753
+ Assumption:
754
+ - if $A > B > C$ then $A > C$
755
+ - if $A = B$ then $B$ can be removed
756
+
757
+ References
758
+ ==========
759
+
760
+ .. [1] https://en.wikipedia.org/wiki/Directed_complete_partial_order
761
+ .. [2] https://en.wikipedia.org/wiki/Lattice_%28order%29
762
+
763
+ See Also
764
+ ========
765
+
766
+ Min : find minimum values
767
+ """
768
+ zero = S.Infinity
769
+ identity = S.NegativeInfinity
770
+
771
+ def fdiff( self, argindex ):
772
+ from sympy.functions.special.delta_functions import Heaviside
773
+ n = len(self.args)
774
+ if 0 < argindex and argindex <= n:
775
+ argindex -= 1
776
+ if n == 2:
777
+ return Heaviside(self.args[argindex] - self.args[1 - argindex])
778
+ newargs = tuple([self.args[i] for i in range(n) if i != argindex])
779
+ return Heaviside(self.args[argindex] - Max(*newargs))
780
+ else:
781
+ raise ArgumentIndexError(self, argindex)
782
+
783
+ def _eval_rewrite_as_Heaviside(self, *args, **kwargs):
784
+ from sympy.functions.special.delta_functions import Heaviside
785
+ return Add(*[j*Mul(*[Heaviside(j - i) for i in args if i!=j]) \
786
+ for j in args])
787
+
788
+ def _eval_rewrite_as_Piecewise(self, *args, **kwargs):
789
+ return _minmax_as_Piecewise('>=', *args)
790
+
791
+ def _eval_is_positive(self):
792
+ return fuzzy_or(a.is_positive for a in self.args)
793
+
794
+ def _eval_is_nonnegative(self):
795
+ return fuzzy_or(a.is_nonnegative for a in self.args)
796
+
797
+ def _eval_is_negative(self):
798
+ return fuzzy_and(a.is_negative for a in self.args)
799
+
800
+
801
+ class Min(MinMaxBase, Application):
802
+ """
803
+ Return, if possible, the minimum value of the list.
804
+ It is named ``Min`` and not ``min`` to avoid conflicts
805
+ with the built-in function ``min``.
806
+
807
+ Examples
808
+ ========
809
+
810
+ >>> from sympy import Min, Symbol, oo
811
+ >>> from sympy.abc import x, y
812
+ >>> p = Symbol('p', positive=True)
813
+ >>> n = Symbol('n', negative=True)
814
+
815
+ >>> Min(x, -2)
816
+ Min(-2, x)
817
+ >>> Min(x, -2).subs(x, 3)
818
+ -2
819
+ >>> Min(p, -3)
820
+ -3
821
+ >>> Min(x, y)
822
+ Min(x, y)
823
+ >>> Min(n, 8, p, -7, p, oo)
824
+ Min(-7, n)
825
+
826
+ See Also
827
+ ========
828
+
829
+ Max : find maximum values
830
+ """
831
+ zero = S.NegativeInfinity
832
+ identity = S.Infinity
833
+
834
+ def fdiff( self, argindex ):
835
+ from sympy.functions.special.delta_functions import Heaviside
836
+ n = len(self.args)
837
+ if 0 < argindex and argindex <= n:
838
+ argindex -= 1
839
+ if n == 2:
840
+ return Heaviside( self.args[1-argindex] - self.args[argindex] )
841
+ newargs = tuple([ self.args[i] for i in range(n) if i != argindex])
842
+ return Heaviside( Min(*newargs) - self.args[argindex] )
843
+ else:
844
+ raise ArgumentIndexError(self, argindex)
845
+
846
+ def _eval_rewrite_as_Heaviside(self, *args, **kwargs):
847
+ from sympy.functions.special.delta_functions import Heaviside
848
+ return Add(*[j*Mul(*[Heaviside(i-j) for i in args if i!=j]) \
849
+ for j in args])
850
+
851
+ def _eval_rewrite_as_Piecewise(self, *args, **kwargs):
852
+ return _minmax_as_Piecewise('<=', *args)
853
+
854
+ def _eval_is_positive(self):
855
+ return fuzzy_and(a.is_positive for a in self.args)
856
+
857
+ def _eval_is_nonnegative(self):
858
+ return fuzzy_and(a.is_nonnegative for a in self.args)
859
+
860
+ def _eval_is_negative(self):
861
+ return fuzzy_or(a.is_negative for a in self.args)
862
+
863
+
864
+ class Rem(Function):
865
+ """Returns the remainder when ``p`` is divided by ``q`` where ``p`` is finite
866
+ and ``q`` is not equal to zero. The result, ``p - int(p/q)*q``, has the same sign
867
+ as the divisor.
868
+
869
+ Parameters
870
+ ==========
871
+
872
+ p : Expr
873
+ Dividend.
874
+
875
+ q : Expr
876
+ Divisor.
877
+
878
+ Notes
879
+ =====
880
+
881
+ ``Rem`` corresponds to the ``%`` operator in C.
882
+
883
+ Examples
884
+ ========
885
+
886
+ >>> from sympy.abc import x, y
887
+ >>> from sympy import Rem
888
+ >>> Rem(x**3, y)
889
+ Rem(x**3, y)
890
+ >>> Rem(x**3, y).subs({x: -5, y: 3})
891
+ -2
892
+
893
+ See Also
894
+ ========
895
+
896
+ Mod
897
+ """
898
+ kind = NumberKind
899
+
900
+ @classmethod
901
+ def eval(cls, p, q):
902
+ """Return the function remainder if both p, q are numbers and q is not
903
+ zero.
904
+ """
905
+
906
+ if q.is_zero:
907
+ raise ZeroDivisionError("Division by zero")
908
+ if p is S.NaN or q is S.NaN or p.is_finite is False or q.is_finite is False:
909
+ return S.NaN
910
+ if p is S.Zero or p in (q, -q) or (p.is_integer and q == 1):
911
+ return S.Zero
912
+
913
+ if q.is_Number:
914
+ if p.is_Number:
915
+ return p - Integer(p/q)*q
venv/lib/python3.10/site-packages/sympy/functions/elementary/piecewise.py ADDED
@@ -0,0 +1,1506 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ from sympy.core import S, Function, diff, Tuple, Dummy, Mul
2
+ from sympy.core.basic import Basic, as_Basic
3
+ from sympy.core.numbers import Rational, NumberSymbol, _illegal
4
+ from sympy.core.parameters import global_parameters
5
+ from sympy.core.relational import (Lt, Gt, Eq, Ne, Relational,
6
+ _canonical, _canonical_coeff)
7
+ from sympy.core.sorting import ordered
8
+ from sympy.functions.elementary.miscellaneous import Max, Min
9
+ from sympy.logic.boolalg import (And, Boolean, distribute_and_over_or, Not,
10
+ true, false, Or, ITE, simplify_logic, to_cnf, distribute_or_over_and)
11
+ from sympy.utilities.iterables import uniq, sift, common_prefix
12
+ from sympy.utilities.misc import filldedent, func_name
13
+
14
+ from itertools import product
15
+
16
+ Undefined = S.NaN # Piecewise()
17
+
18
+ class ExprCondPair(Tuple):
19
+ """Represents an expression, condition pair."""
20
+
21
+ def __new__(cls, expr, cond):
22
+ expr = as_Basic(expr)
23
+ if cond == True:
24
+ return Tuple.__new__(cls, expr, true)
25
+ elif cond == False:
26
+ return Tuple.__new__(cls, expr, false)
27
+ elif isinstance(cond, Basic) and cond.has(Piecewise):
28
+ cond = piecewise_fold(cond)
29
+ if isinstance(cond, Piecewise):
30
+ cond = cond.rewrite(ITE)
31
+
32
+ if not isinstance(cond, Boolean):
33
+ raise TypeError(filldedent('''
34
+ Second argument must be a Boolean,
35
+ not `%s`''' % func_name(cond)))
36
+ return Tuple.__new__(cls, expr, cond)
37
+
38
+ @property
39
+ def expr(self):
40
+ """
41
+ Returns the expression of this pair.
42
+ """
43
+ return self.args[0]
44
+
45
+ @property
46
+ def cond(self):
47
+ """
48
+ Returns the condition of this pair.
49
+ """
50
+ return self.args[1]
51
+
52
+ @property
53
+ def is_commutative(self):
54
+ return self.expr.is_commutative
55
+
56
+ def __iter__(self):
57
+ yield self.expr
58
+ yield self.cond
59
+
60
+ def _eval_simplify(self, **kwargs):
61
+ return self.func(*[a.simplify(**kwargs) for a in self.args])
62
+
63
+
64
+ class Piecewise(Function):
65
+ """
66
+ Represents a piecewise function.
67
+
68
+ Usage:
69
+
70
+ Piecewise( (expr,cond), (expr,cond), ... )
71
+ - Each argument is a 2-tuple defining an expression and condition
72
+ - The conds are evaluated in turn returning the first that is True.
73
+ If any of the evaluated conds are not explicitly False,
74
+ e.g. ``x < 1``, the function is returned in symbolic form.
75
+ - If the function is evaluated at a place where all conditions are False,
76
+ nan will be returned.
77
+ - Pairs where the cond is explicitly False, will be removed and no pair
78
+ appearing after a True condition will ever be retained. If a single
79
+ pair with a True condition remains, it will be returned, even when
80
+ evaluation is False.
81
+
82
+ Examples
83
+ ========
84
+
85
+ >>> from sympy import Piecewise, log, piecewise_fold
86
+ >>> from sympy.abc import x, y
87
+ >>> f = x**2
88
+ >>> g = log(x)
89
+ >>> p = Piecewise((0, x < -1), (f, x <= 1), (g, True))
90
+ >>> p.subs(x,1)
91
+ 1
92
+ >>> p.subs(x,5)
93
+ log(5)
94
+
95
+ Booleans can contain Piecewise elements:
96
+
97
+ >>> cond = (x < y).subs(x, Piecewise((2, x < 0), (3, True))); cond
98
+ Piecewise((2, x < 0), (3, True)) < y
99
+
100
+ The folded version of this results in a Piecewise whose
101
+ expressions are Booleans:
102
+
103
+ >>> folded_cond = piecewise_fold(cond); folded_cond
104
+ Piecewise((2 < y, x < 0), (3 < y, True))
105
+
106
+ When a Boolean containing Piecewise (like cond) or a Piecewise
107
+ with Boolean expressions (like folded_cond) is used as a condition,
108
+ it is converted to an equivalent :class:`~.ITE` object:
109
+
110
+ >>> Piecewise((1, folded_cond))
111
+ Piecewise((1, ITE(x < 0, y > 2, y > 3)))
112
+
113
+ When a condition is an ``ITE``, it will be converted to a simplified
114
+ Boolean expression:
115
+
116
+ >>> piecewise_fold(_)
117
+ Piecewise((1, ((x >= 0) | (y > 2)) & ((y > 3) | (x < 0))))
118
+
119
+ See Also
120
+ ========
121
+
122
+ piecewise_fold
123
+ piecewise_exclusive
124
+ ITE
125
+ """
126
+
127
+ nargs = None
128
+ is_Piecewise = True
129
+
130
+ def __new__(cls, *args, **options):
131
+ if len(args) == 0:
132
+ raise TypeError("At least one (expr, cond) pair expected.")
133
+ # (Try to) sympify args first
134
+ newargs = []
135
+ for ec in args:
136
+ # ec could be a ExprCondPair or a tuple
137
+ pair = ExprCondPair(*getattr(ec, 'args', ec))
138
+ cond = pair.cond
139
+ if cond is false:
140
+ continue
141
+ newargs.append(pair)
142
+ if cond is true:
143
+ break
144
+
145
+ eval = options.pop('evaluate', global_parameters.evaluate)
146
+ if eval:
147
+ r = cls.eval(*newargs)
148
+ if r is not None:
149
+ return r
150
+ elif len(newargs) == 1 and newargs[0].cond == True:
151
+ return newargs[0].expr
152
+
153
+ return Basic.__new__(cls, *newargs, **options)
154
+
155
+ @classmethod
156
+ def eval(cls, *_args):
157
+ """Either return a modified version of the args or, if no
158
+ modifications were made, return None.
159
+
160
+ Modifications that are made here:
161
+
162
+ 1. relationals are made canonical
163
+ 2. any False conditions are dropped
164
+ 3. any repeat of a previous condition is ignored
165
+ 4. any args past one with a true condition are dropped
166
+
167
+ If there are no args left, nan will be returned.
168
+ If there is a single arg with a True condition, its
169
+ corresponding expression will be returned.
170
+
171
+ EXAMPLES
172
+ ========
173
+
174
+ >>> from sympy import Piecewise
175
+ >>> from sympy.abc import x
176
+ >>> cond = -x < -1
177
+ >>> args = [(1, cond), (4, cond), (3, False), (2, True), (5, x < 1)]
178
+ >>> Piecewise(*args, evaluate=False)
179
+ Piecewise((1, -x < -1), (4, -x < -1), (2, True))
180
+ >>> Piecewise(*args)
181
+ Piecewise((1, x > 1), (2, True))
182
+ """
183
+ if not _args:
184
+ return Undefined
185
+
186
+ if len(_args) == 1 and _args[0][-1] == True:
187
+ return _args[0][0]
188
+
189
+ newargs = _piecewise_collapse_arguments(_args)
190
+
191
+ # some conditions may have been redundant
192
+ missing = len(newargs) != len(_args)
193
+ # some conditions may have changed
194
+ same = all(a == b for a, b in zip(newargs, _args))
195
+ # if either change happened we return the expr with the
196
+ # updated args
197
+ if not newargs:
198
+ raise ValueError(filldedent('''
199
+ There are no conditions (or none that
200
+ are not trivially false) to define an
201
+ expression.'''))
202
+ if missing or not same:
203
+ return cls(*newargs)
204
+
205
+ def doit(self, **hints):
206
+ """
207
+ Evaluate this piecewise function.
208
+ """
209
+ newargs = []
210
+ for e, c in self.args:
211
+ if hints.get('deep', True):
212
+ if isinstance(e, Basic):
213
+ newe = e.doit(**hints)
214
+ if newe != self:
215
+ e = newe
216
+ if isinstance(c, Basic):
217
+ c = c.doit(**hints)
218
+ newargs.append((e, c))
219
+ return self.func(*newargs)
220
+
221
+ def _eval_simplify(self, **kwargs):
222
+ return piecewise_simplify(self, **kwargs)
223
+
224
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
225
+ for e, c in self.args:
226
+ if c == True or c.subs(x, 0) == True:
227
+ return e.as_leading_term(x)
228
+
229
+ def _eval_adjoint(self):
230
+ return self.func(*[(e.adjoint(), c) for e, c in self.args])
231
+
232
+ def _eval_conjugate(self):
233
+ return self.func(*[(e.conjugate(), c) for e, c in self.args])
234
+
235
+ def _eval_derivative(self, x):
236
+ return self.func(*[(diff(e, x), c) for e, c in self.args])
237
+
238
+ def _eval_evalf(self, prec):
239
+ return self.func(*[(e._evalf(prec), c) for e, c in self.args])
240
+
241
+ def _eval_is_meromorphic(self, x, a):
242
+ # Conditions often implicitly assume that the argument is real.
243
+ # Hence, there needs to be some check for as_set.
244
+ if not a.is_real:
245
+ return None
246
+
247
+ # Then, scan ExprCondPairs in the given order to find a piece that would contain a,
248
+ # possibly as a boundary point.
249
+ for e, c in self.args:
250
+ cond = c.subs(x, a)
251
+
252
+ if cond.is_Relational:
253
+ return None
254
+ if a in c.as_set().boundary:
255
+ return None
256
+ # Apply expression if a is an interior point of the domain of e.
257
+ if cond:
258
+ return e._eval_is_meromorphic(x, a)
259
+
260
+ def piecewise_integrate(self, x, **kwargs):
261
+ """Return the Piecewise with each expression being
262
+ replaced with its antiderivative. To obtain a continuous
263
+ antiderivative, use the :func:`~.integrate` function or method.
264
+
265
+ Examples
266
+ ========
267
+
268
+ >>> from sympy import Piecewise
269
+ >>> from sympy.abc import x
270
+ >>> p = Piecewise((0, x < 0), (1, x < 1), (2, True))
271
+ >>> p.piecewise_integrate(x)
272
+ Piecewise((0, x < 0), (x, x < 1), (2*x, True))
273
+
274
+ Note that this does not give a continuous function, e.g.
275
+ at x = 1 the 3rd condition applies and the antiderivative
276
+ there is 2*x so the value of the antiderivative is 2:
277
+
278
+ >>> anti = _
279
+ >>> anti.subs(x, 1)
280
+ 2
281
+
282
+ The continuous derivative accounts for the integral *up to*
283
+ the point of interest, however:
284
+
285
+ >>> p.integrate(x)
286
+ Piecewise((0, x < 0), (x, x < 1), (2*x - 1, True))
287
+ >>> _.subs(x, 1)
288
+ 1
289
+
290
+ See Also
291
+ ========
292
+ Piecewise._eval_integral
293
+ """
294
+ from sympy.integrals import integrate
295
+ return self.func(*[(integrate(e, x, **kwargs), c) for e, c in self.args])
296
+
297
+ def _handle_irel(self, x, handler):
298
+ """Return either None (if the conditions of self depend only on x) else
299
+ a Piecewise expression whose expressions (handled by the handler that
300
+ was passed) are paired with the governing x-independent relationals,
301
+ e.g. Piecewise((A, a(x) & b(y)), (B, c(x) | c(y)) ->
302
+ Piecewise(
303
+ (handler(Piecewise((A, a(x) & True), (B, c(x) | True)), b(y) & c(y)),
304
+ (handler(Piecewise((A, a(x) & True), (B, c(x) | False)), b(y)),
305
+ (handler(Piecewise((A, a(x) & False), (B, c(x) | True)), c(y)),
306
+ (handler(Piecewise((A, a(x) & False), (B, c(x) | False)), True))
307
+ """
308
+ # identify governing relationals
309
+ rel = self.atoms(Relational)
310
+ irel = list(ordered([r for r in rel if x not in r.free_symbols
311
+ and r not in (S.true, S.false)]))
312
+ if irel:
313
+ args = {}
314
+ exprinorder = []
315
+ for truth in product((1, 0), repeat=len(irel)):
316
+ reps = dict(zip(irel, truth))
317
+ # only store the true conditions since the false are implied
318
+ # when they appear lower in the Piecewise args
319
+ if 1 not in truth:
320
+ cond = None # flag this one so it doesn't get combined
321
+ else:
322
+ andargs = Tuple(*[i for i in reps if reps[i]])
323
+ free = list(andargs.free_symbols)
324
+ if len(free) == 1:
325
+ from sympy.solvers.inequalities import (
326
+ reduce_inequalities, _solve_inequality)
327
+ try:
328
+ t = reduce_inequalities(andargs, free[0])
329
+ # ValueError when there are potentially
330
+ # nonvanishing imaginary parts
331
+ except (ValueError, NotImplementedError):
332
+ # at least isolate free symbol on left
333
+ t = And(*[_solve_inequality(
334
+ a, free[0], linear=True)
335
+ for a in andargs])
336
+ else:
337
+ t = And(*andargs)
338
+ if t is S.false:
339
+ continue # an impossible combination
340
+ cond = t
341
+ expr = handler(self.xreplace(reps))
342
+ if isinstance(expr, self.func) and len(expr.args) == 1:
343
+ expr, econd = expr.args[0]
344
+ cond = And(econd, True if cond is None else cond)
345
+ # the ec pairs are being collected since all possibilities
346
+ # are being enumerated, but don't put the last one in since
347
+ # its expr might match a previous expression and it
348
+ # must appear last in the args
349
+ if cond is not None:
350
+ args.setdefault(expr, []).append(cond)
351
+ # but since we only store the true conditions we must maintain
352
+ # the order so that the expression with the most true values
353
+ # comes first
354
+ exprinorder.append(expr)
355
+ # convert collected conditions as args of Or
356
+ for k in args:
357
+ args[k] = Or(*args[k])
358
+ # take them in the order obtained
359
+ args = [(e, args[e]) for e in uniq(exprinorder)]
360
+ # add in the last arg
361
+ args.append((expr, True))
362
+ return Piecewise(*args)
363
+
364
+ def _eval_integral(self, x, _first=True, **kwargs):
365
+ """Return the indefinite integral of the
366
+ Piecewise such that subsequent substitution of x with a
367
+ value will give the value of the integral (not including
368
+ the constant of integration) up to that point. To only
369
+ integrate the individual parts of Piecewise, use the
370
+ ``piecewise_integrate`` method.
371
+
372
+ Examples
373
+ ========
374
+
375
+ >>> from sympy import Piecewise
376
+ >>> from sympy.abc import x
377
+ >>> p = Piecewise((0, x < 0), (1, x < 1), (2, True))
378
+ >>> p.integrate(x)
379
+ Piecewise((0, x < 0), (x, x < 1), (2*x - 1, True))
380
+ >>> p.piecewise_integrate(x)
381
+ Piecewise((0, x < 0), (x, x < 1), (2*x, True))
382
+
383
+ See Also
384
+ ========
385
+ Piecewise.piecewise_integrate
386
+ """
387
+ from sympy.integrals.integrals import integrate
388
+
389
+ if _first:
390
+ def handler(ipw):
391
+ if isinstance(ipw, self.func):
392
+ return ipw._eval_integral(x, _first=False, **kwargs)
393
+ else:
394
+ return ipw.integrate(x, **kwargs)
395
+ irv = self._handle_irel(x, handler)
396
+ if irv is not None:
397
+ return irv
398
+
399
+ # handle a Piecewise from -oo to oo with and no x-independent relationals
400
+ # -----------------------------------------------------------------------
401
+ ok, abei = self._intervals(x)
402
+ if not ok:
403
+ from sympy.integrals.integrals import Integral
404
+ return Integral(self, x) # unevaluated
405
+
406
+ pieces = [(a, b) for a, b, _, _ in abei]
407
+ oo = S.Infinity
408
+ done = [(-oo, oo, -1)]
409
+ for k, p in enumerate(pieces):
410
+ if p == (-oo, oo):
411
+ # all undone intervals will get this key
412
+ for j, (a, b, i) in enumerate(done):
413
+ if i == -1:
414
+ done[j] = a, b, k
415
+ break # nothing else to consider
416
+ N = len(done) - 1
417
+ for j, (a, b, i) in enumerate(reversed(done)):
418
+ if i == -1:
419
+ j = N - j
420
+ done[j: j + 1] = _clip(p, (a, b), k)
421
+ done = [(a, b, i) for a, b, i in done if a != b]
422
+
423
+ # append an arg if there is a hole so a reference to
424
+ # argument -1 will give Undefined
425
+ if any(i == -1 for (a, b, i) in done):
426
+ abei.append((-oo, oo, Undefined, -1))
427
+
428
+ # return the sum of the intervals
429
+ args = []
430
+ sum = None
431
+ for a, b, i in done:
432
+ anti = integrate(abei[i][-2], x, **kwargs)
433
+ if sum is None:
434
+ sum = anti
435
+ else:
436
+ sum = sum.subs(x, a)
437
+ e = anti._eval_interval(x, a, x)
438
+ if sum.has(*_illegal) or e.has(*_illegal):
439
+ sum = anti
440
+ else:
441
+ sum += e
442
+ # see if we know whether b is contained in original
443
+ # condition
444
+ if b is S.Infinity:
445
+ cond = True
446
+ elif self.args[abei[i][-1]].cond.subs(x, b) == False:
447
+ cond = (x < b)
448
+ else:
449
+ cond = (x <= b)
450
+ args.append((sum, cond))
451
+ return Piecewise(*args)
452
+
453
+ def _eval_interval(self, sym, a, b, _first=True):
454
+ """Evaluates the function along the sym in a given interval [a, b]"""
455
+ # FIXME: Currently complex intervals are not supported. A possible
456
+ # replacement algorithm, discussed in issue 5227, can be found in the
457
+ # following papers;
458
+ # http://portal.acm.org/citation.cfm?id=281649
459
+ # http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.70.4127&rep=rep1&type=pdf
460
+
461
+ if a is None or b is None:
462
+ # In this case, it is just simple substitution
463
+ return super()._eval_interval(sym, a, b)
464
+ else:
465
+ x, lo, hi = map(as_Basic, (sym, a, b))
466
+
467
+ if _first: # get only x-dependent relationals
468
+ def handler(ipw):
469
+ if isinstance(ipw, self.func):
470
+ return ipw._eval_interval(x, lo, hi, _first=None)
471
+ else:
472
+ return ipw._eval_interval(x, lo, hi)
473
+ irv = self._handle_irel(x, handler)
474
+ if irv is not None:
475
+ return irv
476
+
477
+ if (lo < hi) is S.false or (
478
+ lo is S.Infinity or hi is S.NegativeInfinity):
479
+ rv = self._eval_interval(x, hi, lo, _first=False)
480
+ if isinstance(rv, Piecewise):
481
+ rv = Piecewise(*[(-e, c) for e, c in rv.args])
482
+ else:
483
+ rv = -rv
484
+ return rv
485
+
486
+ if (lo < hi) is S.true or (
487
+ hi is S.Infinity or lo is S.NegativeInfinity):
488
+ pass
489
+ else:
490
+ _a = Dummy('lo')
491
+ _b = Dummy('hi')
492
+ a = lo if lo.is_comparable else _a
493
+ b = hi if hi.is_comparable else _b
494
+ pos = self._eval_interval(x, a, b, _first=False)
495
+ if a == _a and b == _b:
496
+ # it's purely symbolic so just swap lo and hi and
497
+ # change the sign to get the value for when lo > hi
498
+ neg, pos = (-pos.xreplace({_a: hi, _b: lo}),
499
+ pos.xreplace({_a: lo, _b: hi}))
500
+ else:
501
+ # at least one of the bounds was comparable, so allow
502
+ # _eval_interval to use that information when computing
503
+ # the interval with lo and hi reversed
504
+ neg, pos = (-self._eval_interval(x, hi, lo, _first=False),
505
+ pos.xreplace({_a: lo, _b: hi}))
506
+
507
+ # allow simplification based on ordering of lo and hi
508
+ p = Dummy('', positive=True)
509
+ if lo.is_Symbol:
510
+ pos = pos.xreplace({lo: hi - p}).xreplace({p: hi - lo})
511
+ neg = neg.xreplace({lo: hi + p}).xreplace({p: lo - hi})
512
+ elif hi.is_Symbol:
513
+ pos = pos.xreplace({hi: lo + p}).xreplace({p: hi - lo})
514
+ neg = neg.xreplace({hi: lo - p}).xreplace({p: lo - hi})
515
+ # evaluate limits that may have unevaluate Min/Max
516
+ touch = lambda _: _.replace(
517
+ lambda x: isinstance(x, (Min, Max)),
518
+ lambda x: x.func(*x.args))
519
+ neg = touch(neg)
520
+ pos = touch(pos)
521
+ # assemble return expression; make the first condition be Lt
522
+ # b/c then the first expression will look the same whether
523
+ # the lo or hi limit is symbolic
524
+ if a == _a: # the lower limit was symbolic
525
+ rv = Piecewise(
526
+ (pos,
527
+ lo < hi),
528
+ (neg,
529
+ True))
530
+ else:
531
+ rv = Piecewise(
532
+ (neg,
533
+ hi < lo),
534
+ (pos,
535
+ True))
536
+
537
+ if rv == Undefined:
538
+ raise ValueError("Can't integrate across undefined region.")
539
+ if any(isinstance(i, Piecewise) for i in (pos, neg)):
540
+ rv = piecewise_fold(rv)
541
+ return rv
542
+
543
+ # handle a Piecewise with lo <= hi and no x-independent relationals
544
+ # -----------------------------------------------------------------
545
+ ok, abei = self._intervals(x)
546
+ if not ok:
547
+ from sympy.integrals.integrals import Integral
548
+ # not being able to do the interval of f(x) can
549
+ # be stated as not being able to do the integral
550
+ # of f'(x) over the same range
551
+ return Integral(self.diff(x), (x, lo, hi)) # unevaluated
552
+
553
+ pieces = [(a, b) for a, b, _, _ in abei]
554
+ done = [(lo, hi, -1)]
555
+ oo = S.Infinity
556
+ for k, p in enumerate(pieces):
557
+ if p[:2] == (-oo, oo):
558
+ # all undone intervals will get this key
559
+ for j, (a, b, i) in enumerate(done):
560
+ if i == -1:
561
+ done[j] = a, b, k
562
+ break # nothing else to consider
563
+ N = len(done) - 1
564
+ for j, (a, b, i) in enumerate(reversed(done)):
565
+ if i == -1:
566
+ j = N - j
567
+ done[j: j + 1] = _clip(p, (a, b), k)
568
+ done = [(a, b, i) for a, b, i in done if a != b]
569
+
570
+ # return the sum of the intervals
571
+ sum = S.Zero
572
+ upto = None
573
+ for a, b, i in done:
574
+ if i == -1:
575
+ if upto is None:
576
+ return Undefined
577
+ # TODO simplify hi <= upto
578
+ return Piecewise((sum, hi <= upto), (Undefined, True))
579
+ sum += abei[i][-2]._eval_interval(x, a, b)
580
+ upto = b
581
+ return sum
582
+
583
+ def _intervals(self, sym, err_on_Eq=False):
584
+ r"""Return a bool and a message (when bool is False), else a
585
+ list of unique tuples, (a, b, e, i), where a and b
586
+ are the lower and upper bounds in which the expression e of
587
+ argument i in self is defined and $a < b$ (when involving
588
+ numbers) or $a \le b$ when involving symbols.
589
+
590
+ If there are any relationals not involving sym, or any
591
+ relational cannot be solved for sym, the bool will be False
592
+ a message be given as the second return value. The calling
593
+ routine should have removed such relationals before calling
594
+ this routine.
595
+
596
+ The evaluated conditions will be returned as ranges.
597
+ Discontinuous ranges will be returned separately with
598
+ identical expressions. The first condition that evaluates to
599
+ True will be returned as the last tuple with a, b = -oo, oo.
600
+ """
601
+ from sympy.solvers.inequalities import _solve_inequality
602
+
603
+ assert isinstance(self, Piecewise)
604
+
605
+ def nonsymfail(cond):
606
+ return False, filldedent('''
607
+ A condition not involving
608
+ %s appeared: %s''' % (sym, cond))
609
+
610
+ def _solve_relational(r):
611
+ if sym not in r.free_symbols:
612
+ return nonsymfail(r)
613
+ try:
614
+ rv = _solve_inequality(r, sym)
615
+ except NotImplementedError:
616
+ return False, 'Unable to solve relational %s for %s.' % (r, sym)
617
+ if isinstance(rv, Relational):
618
+ free = rv.args[1].free_symbols
619
+ if rv.args[0] != sym or sym in free:
620
+ return False, 'Unable to solve relational %s for %s.' % (r, sym)
621
+ if rv.rel_op == '==':
622
+ # this equality has been affirmed to have the form
623
+ # Eq(sym, rhs) where rhs is sym-free; it represents
624
+ # a zero-width interval which will be ignored
625
+ # whether it is an isolated condition or contained
626
+ # within an And or an Or
627
+ rv = S.false
628
+ elif rv.rel_op == '!=':
629
+ try:
630
+ rv = Or(sym < rv.rhs, sym > rv.rhs)
631
+ except TypeError:
632
+ # e.g. x != I ==> all real x satisfy
633
+ rv = S.true
634
+ elif rv == (S.NegativeInfinity < sym) & (sym < S.Infinity):
635
+ rv = S.true
636
+ return True, rv
637
+
638
+ args = list(self.args)
639
+ # make self canonical wrt Relationals
640
+ keys = self.atoms(Relational)
641
+ reps = {}
642
+ for r in keys:
643
+ ok, s = _solve_relational(r)
644
+ if ok != True:
645
+ return False, ok
646
+ reps[r] = s
647
+ # process args individually so if any evaluate, their position
648
+ # in the original Piecewise will be known
649
+ args = [i.xreplace(reps) for i in self.args]
650
+
651
+ # precondition args
652
+ expr_cond = []
653
+ default = idefault = None
654
+ for i, (expr, cond) in enumerate(args):
655
+ if cond is S.false:
656
+ continue
657
+ if cond is S.true:
658
+ default = expr
659
+ idefault = i
660
+ break
661
+ if isinstance(cond, Eq):
662
+ # unanticipated condition, but it is here in case a
663
+ # replacement caused an Eq to appear
664
+ if err_on_Eq:
665
+ return False, 'encountered Eq condition: %s' % cond
666
+ continue # zero width interval
667
+
668
+ cond = to_cnf(cond)
669
+ if isinstance(cond, And):
670
+ cond = distribute_or_over_and(cond)
671
+
672
+ if isinstance(cond, Or):
673
+ expr_cond.extend(
674
+ [(i, expr, o) for o in cond.args
675
+ if not isinstance(o, Eq)])
676
+ elif cond is not S.false:
677
+ expr_cond.append((i, expr, cond))
678
+ elif cond is S.true:
679
+ default = expr
680
+ idefault = i
681
+ break
682
+
683
+ # determine intervals represented by conditions
684
+ int_expr = []
685
+ for iarg, expr, cond in expr_cond:
686
+ if isinstance(cond, And):
687
+ lower = S.NegativeInfinity
688
+ upper = S.Infinity
689
+ exclude = []
690
+ for cond2 in cond.args:
691
+ if not isinstance(cond2, Relational):
692
+ return False, 'expecting only Relationals'
693
+ if isinstance(cond2, Eq):
694
+ lower = upper # ignore
695
+ if err_on_Eq:
696
+ return False, 'encountered secondary Eq condition'
697
+ break
698
+ elif isinstance(cond2, Ne):
699
+ l, r = cond2.args
700
+ if l == sym:
701
+ exclude.append(r)
702
+ elif r == sym:
703
+ exclude.append(l)
704
+ else:
705
+ return nonsymfail(cond2)
706
+ continue
707
+ elif cond2.lts == sym:
708
+ upper = Min(cond2.gts, upper)
709
+ elif cond2.gts == sym:
710
+ lower = Max(cond2.lts, lower)
711
+ else:
712
+ return nonsymfail(cond2) # should never get here
713
+ if exclude:
714
+ exclude = list(ordered(exclude))
715
+ newcond = []
716
+ for i, e in enumerate(exclude):
717
+ if e < lower == True or e > upper == True:
718
+ continue
719
+ if not newcond:
720
+ newcond.append((None, lower)) # add a primer
721
+ newcond.append((newcond[-1][1], e))
722
+ newcond.append((newcond[-1][1], upper))
723
+ newcond.pop(0) # remove the primer
724
+ expr_cond.extend([(iarg, expr, And(i[0] < sym, sym < i[1])) for i in newcond])
725
+ continue
726
+ elif isinstance(cond, Relational) and cond.rel_op != '!=':
727
+ lower, upper = cond.lts, cond.gts # part 1: initialize with givens
728
+ if cond.lts == sym: # part 1a: expand the side ...
729
+ lower = S.NegativeInfinity # e.g. x <= 0 ---> -oo <= 0
730
+ elif cond.gts == sym: # part 1a: ... that can be expanded
731
+ upper = S.Infinity # e.g. x >= 0 ---> oo >= 0
732
+ else:
733
+ return nonsymfail(cond)
734
+ else:
735
+ return False, 'unrecognized condition: %s' % cond
736
+
737
+ lower, upper = lower, Max(lower, upper)
738
+ if err_on_Eq and lower == upper:
739
+ return False, 'encountered Eq condition'
740
+ if (lower >= upper) is not S.true:
741
+ int_expr.append((lower, upper, expr, iarg))
742
+
743
+ if default is not None:
744
+ int_expr.append(
745
+ (S.NegativeInfinity, S.Infinity, default, idefault))
746
+
747
+ return True, list(uniq(int_expr))
748
+
749
+ def _eval_nseries(self, x, n, logx, cdir=0):
750
+ args = [(ec.expr._eval_nseries(x, n, logx), ec.cond) for ec in self.args]
751
+ return self.func(*args)
752
+
753
+ def _eval_power(self, s):
754
+ return self.func(*[(e**s, c) for e, c in self.args])
755
+
756
+ def _eval_subs(self, old, new):
757
+ # this is strictly not necessary, but we can keep track
758
+ # of whether True or False conditions arise and be
759
+ # somewhat more efficient by avoiding other substitutions
760
+ # and avoiding invalid conditions that appear after a
761
+ # True condition
762
+ args = list(self.args)
763
+ args_exist = False
764
+ for i, (e, c) in enumerate(args):
765
+ c = c._subs(old, new)
766
+ if c != False:
767
+ args_exist = True
768
+ e = e._subs(old, new)
769
+ args[i] = (e, c)
770
+ if c == True:
771
+ break
772
+ if not args_exist:
773
+ args = ((Undefined, True),)
774
+ return self.func(*args)
775
+
776
+ def _eval_transpose(self):
777
+ return self.func(*[(e.transpose(), c) for e, c in self.args])
778
+
779
+ def _eval_template_is_attr(self, is_attr):
780
+ b = None
781
+ for expr, _ in self.args:
782
+ a = getattr(expr, is_attr)
783
+ if a is None:
784
+ return
785
+ if b is None:
786
+ b = a
787
+ elif b is not a:
788
+ return
789
+ return b
790
+
791
+ _eval_is_finite = lambda self: self._eval_template_is_attr(
792
+ 'is_finite')
793
+ _eval_is_complex = lambda self: self._eval_template_is_attr('is_complex')
794
+ _eval_is_even = lambda self: self._eval_template_is_attr('is_even')
795
+ _eval_is_imaginary = lambda self: self._eval_template_is_attr(
796
+ 'is_imaginary')
797
+ _eval_is_integer = lambda self: self._eval_template_is_attr('is_integer')
798
+ _eval_is_irrational = lambda self: self._eval_template_is_attr(
799
+ 'is_irrational')
800
+ _eval_is_negative = lambda self: self._eval_template_is_attr('is_negative')
801
+ _eval_is_nonnegative = lambda self: self._eval_template_is_attr(
802
+ 'is_nonnegative')
803
+ _eval_is_nonpositive = lambda self: self._eval_template_is_attr(
804
+ 'is_nonpositive')
805
+ _eval_is_nonzero = lambda self: self._eval_template_is_attr(
806
+ 'is_nonzero')
807
+ _eval_is_odd = lambda self: self._eval_template_is_attr('is_odd')
808
+ _eval_is_polar = lambda self: self._eval_template_is_attr('is_polar')
809
+ _eval_is_positive = lambda self: self._eval_template_is_attr('is_positive')
810
+ _eval_is_extended_real = lambda self: self._eval_template_is_attr(
811
+ 'is_extended_real')
812
+ _eval_is_extended_positive = lambda self: self._eval_template_is_attr(
813
+ 'is_extended_positive')
814
+ _eval_is_extended_negative = lambda self: self._eval_template_is_attr(
815
+ 'is_extended_negative')
816
+ _eval_is_extended_nonzero = lambda self: self._eval_template_is_attr(
817
+ 'is_extended_nonzero')
818
+ _eval_is_extended_nonpositive = lambda self: self._eval_template_is_attr(
819
+ 'is_extended_nonpositive')
820
+ _eval_is_extended_nonnegative = lambda self: self._eval_template_is_attr(
821
+ 'is_extended_nonnegative')
822
+ _eval_is_real = lambda self: self._eval_template_is_attr('is_real')
823
+ _eval_is_zero = lambda self: self._eval_template_is_attr(
824
+ 'is_zero')
825
+
826
+ @classmethod
827
+ def __eval_cond(cls, cond):
828
+ """Return the truth value of the condition."""
829
+ if cond == True:
830
+ return True
831
+ if isinstance(cond, Eq):
832
+ try:
833
+ diff = cond.lhs - cond.rhs
834
+ if diff.is_commutative:
835
+ return diff.is_zero
836
+ except TypeError:
837
+ pass
838
+
839
+ def as_expr_set_pairs(self, domain=None):
840
+ """Return tuples for each argument of self that give
841
+ the expression and the interval in which it is valid
842
+ which is contained within the given domain.
843
+ If a condition cannot be converted to a set, an error
844
+ will be raised. The variable of the conditions is
845
+ assumed to be real; sets of real values are returned.
846
+
847
+ Examples
848
+ ========
849
+
850
+ >>> from sympy import Piecewise, Interval
851
+ >>> from sympy.abc import x
852
+ >>> p = Piecewise(
853
+ ... (1, x < 2),
854
+ ... (2,(x > 0) & (x < 4)),
855
+ ... (3, True))
856
+ >>> p.as_expr_set_pairs()
857
+ [(1, Interval.open(-oo, 2)),
858
+ (2, Interval.Ropen(2, 4)),
859
+ (3, Interval(4, oo))]
860
+ >>> p.as_expr_set_pairs(Interval(0, 3))
861
+ [(1, Interval.Ropen(0, 2)),
862
+ (2, Interval(2, 3))]
863
+ """
864
+ if domain is None:
865
+ domain = S.Reals
866
+ exp_sets = []
867
+ U = domain
868
+ complex = not domain.is_subset(S.Reals)
869
+ cond_free = set()
870
+ for expr, cond in self.args:
871
+ cond_free |= cond.free_symbols
872
+ if len(cond_free) > 1:
873
+ raise NotImplementedError(filldedent('''
874
+ multivariate conditions are not handled.'''))
875
+ if complex:
876
+ for i in cond.atoms(Relational):
877
+ if not isinstance(i, (Eq, Ne)):
878
+ raise ValueError(filldedent('''
879
+ Inequalities in the complex domain are
880
+ not supported. Try the real domain by
881
+ setting domain=S.Reals'''))
882
+ cond_int = U.intersect(cond.as_set())
883
+ U = U - cond_int
884
+ if cond_int != S.EmptySet:
885
+ exp_sets.append((expr, cond_int))
886
+ return exp_sets
887
+
888
+ def _eval_rewrite_as_ITE(self, *args, **kwargs):
889
+ byfree = {}
890
+ args = list(args)
891
+ default = any(c == True for b, c in args)
892
+ for i, (b, c) in enumerate(args):
893
+ if not isinstance(b, Boolean) and b != True:
894
+ raise TypeError(filldedent('''
895
+ Expecting Boolean or bool but got `%s`
896
+ ''' % func_name(b)))
897
+ if c == True:
898
+ break
899
+ # loop over independent conditions for this b
900
+ for c in c.args if isinstance(c, Or) else [c]:
901
+ free = c.free_symbols
902
+ x = free.pop()
903
+ try:
904
+ byfree[x] = byfree.setdefault(
905
+ x, S.EmptySet).union(c.as_set())
906
+ except NotImplementedError:
907
+ if not default:
908
+ raise NotImplementedError(filldedent('''
909
+ A method to determine whether a multivariate
910
+ conditional is consistent with a complete coverage
911
+ of all variables has not been implemented so the
912
+ rewrite is being stopped after encountering `%s`.
913
+ This error would not occur if a default expression
914
+ like `(foo, True)` were given.
915
+ ''' % c))
916
+ if byfree[x] in (S.UniversalSet, S.Reals):
917
+ # collapse the ith condition to True and break
918
+ args[i] = list(args[i])
919
+ c = args[i][1] = True
920
+ break
921
+ if c == True:
922
+ break
923
+ if c != True:
924
+ raise ValueError(filldedent('''
925
+ Conditions must cover all reals or a final default
926
+ condition `(foo, True)` must be given.
927
+ '''))
928
+ last, _ = args[i] # ignore all past ith arg
929
+ for a, c in reversed(args[:i]):
930
+ last = ITE(c, a, last)
931
+ return _canonical(last)
932
+
933
+ def _eval_rewrite_as_KroneckerDelta(self, *args):
934
+ from sympy.functions.special.tensor_functions import KroneckerDelta
935
+
936
+ rules = {
937
+ And: [False, False],
938
+ Or: [True, True],
939
+ Not: [True, False],
940
+ Eq: [None, None],
941
+ Ne: [None, None]
942
+ }
943
+
944
+ class UnrecognizedCondition(Exception):
945
+ pass
946
+
947
+ def rewrite(cond):
948
+ if isinstance(cond, Eq):
949
+ return KroneckerDelta(*cond.args)
950
+ if isinstance(cond, Ne):
951
+ return 1 - KroneckerDelta(*cond.args)
952
+
953
+ cls, args = type(cond), cond.args
954
+ if cls not in rules:
955
+ raise UnrecognizedCondition(cls)
956
+
957
+ b1, b2 = rules[cls]
958
+ k = Mul(*[1 - rewrite(c) for c in args]) if b1 else Mul(*[rewrite(c) for c in args])
959
+
960
+ if b2:
961
+ return 1 - k
962
+ return k
963
+
964
+ conditions = []
965
+ true_value = None
966
+ for value, cond in args:
967
+ if type(cond) in rules:
968
+ conditions.append((value, cond))
969
+ elif cond is S.true:
970
+ if true_value is None:
971
+ true_value = value
972
+ else:
973
+ return
974
+
975
+ if true_value is not None:
976
+ result = true_value
977
+
978
+ for value, cond in conditions[::-1]:
979
+ try:
980
+ k = rewrite(cond)
981
+ result = k * value + (1 - k) * result
982
+ except UnrecognizedCondition:
983
+ return
984
+
985
+ return result
986
+
987
+
988
+ def piecewise_fold(expr, evaluate=True):
989
+ """
990
+ Takes an expression containing a piecewise function and returns the
991
+ expression in piecewise form. In addition, any ITE conditions are
992
+ rewritten in negation normal form and simplified.
993
+
994
+ The final Piecewise is evaluated (default) but if the raw form
995
+ is desired, send ``evaluate=False``; if trivial evaluation is
996
+ desired, send ``evaluate=None`` and duplicate conditions and
997
+ processing of True and False will be handled.
998
+
999
+ Examples
1000
+ ========
1001
+
1002
+ >>> from sympy import Piecewise, piecewise_fold, S
1003
+ >>> from sympy.abc import x
1004
+ >>> p = Piecewise((x, x < 1), (1, S(1) <= x))
1005
+ >>> piecewise_fold(x*p)
1006
+ Piecewise((x**2, x < 1), (x, True))
1007
+
1008
+ See Also
1009
+ ========
1010
+
1011
+ Piecewise
1012
+ piecewise_exclusive
1013
+ """
1014
+ if not isinstance(expr, Basic) or not expr.has(Piecewise):
1015
+ return expr
1016
+
1017
+ new_args = []
1018
+ if isinstance(expr, (ExprCondPair, Piecewise)):
1019
+ for e, c in expr.args:
1020
+ if not isinstance(e, Piecewise):
1021
+ e = piecewise_fold(e)
1022
+ # we don't keep Piecewise in condition because
1023
+ # it has to be checked to see that it's complete
1024
+ # and we convert it to ITE at that time
1025
+ assert not c.has(Piecewise) # pragma: no cover
1026
+ if isinstance(c, ITE):
1027
+ c = c.to_nnf()
1028
+ c = simplify_logic(c, form='cnf')
1029
+ if isinstance(e, Piecewise):
1030
+ new_args.extend([(piecewise_fold(ei), And(ci, c))
1031
+ for ei, ci in e.args])
1032
+ else:
1033
+ new_args.append((e, c))
1034
+ else:
1035
+ # Given
1036
+ # P1 = Piecewise((e11, c1), (e12, c2), A)
1037
+ # P2 = Piecewise((e21, c1), (e22, c2), B)
1038
+ # ...
1039
+ # the folding of f(P1, P2) is trivially
1040
+ # Piecewise(
1041
+ # (f(e11, e21), c1),
1042
+ # (f(e12, e22), c2),
1043
+ # (f(Piecewise(A), Piecewise(B)), True))
1044
+ # Certain objects end up rewriting themselves as thus, so
1045
+ # we do that grouping before the more generic folding.
1046
+ # The following applies this idea when f = Add or f = Mul
1047
+ # (and the expression is commutative).
1048
+ if expr.is_Add or expr.is_Mul and expr.is_commutative:
1049
+ p, args = sift(expr.args, lambda x: x.is_Piecewise, binary=True)
1050
+ pc = sift(p, lambda x: tuple([c for e,c in x.args]))
1051
+ for c in list(ordered(pc)):
1052
+ if len(pc[c]) > 1:
1053
+ pargs = [list(i.args) for i in pc[c]]
1054
+ # the first one is the same; there may be more
1055
+ com = common_prefix(*[
1056
+ [i.cond for i in j] for j in pargs])
1057
+ n = len(com)
1058
+ collected = []
1059
+ for i in range(n):
1060
+ collected.append((
1061
+ expr.func(*[ai[i].expr for ai in pargs]),
1062
+ com[i]))
1063
+ remains = []
1064
+ for a in pargs:
1065
+ if n == len(a): # no more args
1066
+ continue
1067
+ if a[n].cond == True: # no longer Piecewise
1068
+ remains.append(a[n].expr)
1069
+ else: # restore the remaining Piecewise
1070
+ remains.append(
1071
+ Piecewise(*a[n:], evaluate=False))
1072
+ if remains:
1073
+ collected.append((expr.func(*remains), True))
1074
+ args.append(Piecewise(*collected, evaluate=False))
1075
+ continue
1076
+ args.extend(pc[c])
1077
+ else:
1078
+ args = expr.args
1079
+ # fold
1080
+ folded = list(map(piecewise_fold, args))
1081
+ for ec in product(*[
1082
+ (i.args if isinstance(i, Piecewise) else
1083
+ [(i, true)]) for i in folded]):
1084
+ e, c = zip(*ec)
1085
+ new_args.append((expr.func(*e), And(*c)))
1086
+
1087
+ if evaluate is None:
1088
+ # don't return duplicate conditions, otherwise don't evaluate
1089
+ new_args = list(reversed([(e, c) for c, e in {
1090
+ c: e for e, c in reversed(new_args)}.items()]))
1091
+ rv = Piecewise(*new_args, evaluate=evaluate)
1092
+ if evaluate is None and len(rv.args) == 1 and rv.args[0].cond == True:
1093
+ return rv.args[0].expr
1094
+ if any(s.expr.has(Piecewise) for p in rv.atoms(Piecewise) for s in p.args):
1095
+ return piecewise_fold(rv)
1096
+ return rv
1097
+
1098
+
1099
+ def _clip(A, B, k):
1100
+ """Return interval B as intervals that are covered by A (keyed
1101
+ to k) and all other intervals of B not covered by A keyed to -1.
1102
+
1103
+ The reference point of each interval is the rhs; if the lhs is
1104
+ greater than the rhs then an interval of zero width interval will
1105
+ result, e.g. (4, 1) is treated like (1, 1).
1106
+
1107
+ Examples
1108
+ ========
1109
+
1110
+ >>> from sympy.functions.elementary.piecewise import _clip
1111
+ >>> from sympy import Tuple
1112
+ >>> A = Tuple(1, 3)
1113
+ >>> B = Tuple(2, 4)
1114
+ >>> _clip(A, B, 0)
1115
+ [(2, 3, 0), (3, 4, -1)]
1116
+
1117
+ Interpretation: interval portion (2, 3) of interval (2, 4) is
1118
+ covered by interval (1, 3) and is keyed to 0 as requested;
1119
+ interval (3, 4) was not covered by (1, 3) and is keyed to -1.
1120
+ """
1121
+ a, b = B
1122
+ c, d = A
1123
+ c, d = Min(Max(c, a), b), Min(Max(d, a), b)
1124
+ a, b = Min(a, b), b
1125
+ p = []
1126
+ if a != c:
1127
+ p.append((a, c, -1))
1128
+ else:
1129
+ pass
1130
+ if c != d:
1131
+ p.append((c, d, k))
1132
+ else:
1133
+ pass
1134
+ if b != d:
1135
+ if d == c and p and p[-1][-1] == -1:
1136
+ p[-1] = p[-1][0], b, -1
1137
+ else:
1138
+ p.append((d, b, -1))
1139
+ else:
1140
+ pass
1141
+
1142
+ return p
1143
+
1144
+
1145
+ def piecewise_simplify_arguments(expr, **kwargs):
1146
+ from sympy.simplify.simplify import simplify
1147
+
1148
+ # simplify conditions
1149
+ f1 = expr.args[0].cond.free_symbols
1150
+ args = None
1151
+ if len(f1) == 1 and not expr.atoms(Eq):
1152
+ x = f1.pop()
1153
+ # this won't return intervals involving Eq
1154
+ # and it won't handle symbols treated as
1155
+ # booleans
1156
+ ok, abe_ = expr._intervals(x, err_on_Eq=True)
1157
+ def include(c, x, a):
1158
+ "return True if c.subs(x, a) is True, else False"
1159
+ try:
1160
+ return c.subs(x, a) == True
1161
+ except TypeError:
1162
+ return False
1163
+ if ok:
1164
+ args = []
1165
+ covered = S.EmptySet
1166
+ from sympy.sets.sets import Interval
1167
+ for a, b, e, i in abe_:
1168
+ c = expr.args[i].cond
1169
+ incl_a = include(c, x, a)
1170
+ incl_b = include(c, x, b)
1171
+ iv = Interval(a, b, not incl_a, not incl_b)
1172
+ cset = iv - covered
1173
+ if not cset:
1174
+ continue
1175
+ if incl_a and incl_b:
1176
+ if a.is_infinite and b.is_infinite:
1177
+ c = S.true
1178
+ elif b.is_infinite:
1179
+ c = (x >= a)
1180
+ elif a in covered or a.is_infinite:
1181
+ c = (x <= b)
1182
+ else:
1183
+ c = And(a <= x, x <= b)
1184
+ elif incl_a:
1185
+ if a in covered or a.is_infinite:
1186
+ c = (x < b)
1187
+ else:
1188
+ c = And(a <= x, x < b)
1189
+ elif incl_b:
1190
+ if b.is_infinite:
1191
+ c = (x > a)
1192
+ else:
1193
+ c = (x <= b)
1194
+ else:
1195
+ if a in covered:
1196
+ c = (x < b)
1197
+ else:
1198
+ c = And(a < x, x < b)
1199
+ covered |= iv
1200
+ if a is S.NegativeInfinity and incl_a:
1201
+ covered |= {S.NegativeInfinity}
1202
+ if b is S.Infinity and incl_b:
1203
+ covered |= {S.Infinity}
1204
+ args.append((e, c))
1205
+ if not S.Reals.is_subset(covered):
1206
+ args.append((Undefined, True))
1207
+ if args is None:
1208
+ args = list(expr.args)
1209
+ for i in range(len(args)):
1210
+ e, c = args[i]
1211
+ if isinstance(c, Basic):
1212
+ c = simplify(c, **kwargs)
1213
+ args[i] = (e, c)
1214
+
1215
+ # simplify expressions
1216
+ doit = kwargs.pop('doit', None)
1217
+ for i in range(len(args)):
1218
+ e, c = args[i]
1219
+ if isinstance(e, Basic):
1220
+ # Skip doit to avoid growth at every call for some integrals
1221
+ # and sums, see sympy/sympy#17165
1222
+ newe = simplify(e, doit=False, **kwargs)
1223
+ if newe != e:
1224
+ e = newe
1225
+ args[i] = (e, c)
1226
+
1227
+ # restore kwargs flag
1228
+ if doit is not None:
1229
+ kwargs['doit'] = doit
1230
+
1231
+ return Piecewise(*args)
1232
+
1233
+
1234
+ def _piecewise_collapse_arguments(_args):
1235
+ newargs = [] # the unevaluated conditions
1236
+ current_cond = set() # the conditions up to a given e, c pair
1237
+ for expr, cond in _args:
1238
+ cond = cond.replace(
1239
+ lambda _: _.is_Relational, _canonical_coeff)
1240
+ # Check here if expr is a Piecewise and collapse if one of
1241
+ # the conds in expr matches cond. This allows the collapsing
1242
+ # of Piecewise((Piecewise((x,x<0)),x<0)) to Piecewise((x,x<0)).
1243
+ # This is important when using piecewise_fold to simplify
1244
+ # multiple Piecewise instances having the same conds.
1245
+ # Eventually, this code should be able to collapse Piecewise's
1246
+ # having different intervals, but this will probably require
1247
+ # using the new assumptions.
1248
+ if isinstance(expr, Piecewise):
1249
+ unmatching = []
1250
+ for i, (e, c) in enumerate(expr.args):
1251
+ if c in current_cond:
1252
+ # this would already have triggered
1253
+ continue
1254
+ if c == cond:
1255
+ if c != True:
1256
+ # nothing past this condition will ever
1257
+ # trigger and only those args before this
1258
+ # that didn't match a previous condition
1259
+ # could possibly trigger
1260
+ if unmatching:
1261
+ expr = Piecewise(*(
1262
+ unmatching + [(e, c)]))
1263
+ else:
1264
+ expr = e
1265
+ break
1266
+ else:
1267
+ unmatching.append((e, c))
1268
+
1269
+ # check for condition repeats
1270
+ got = False
1271
+ # -- if an And contains a condition that was
1272
+ # already encountered, then the And will be
1273
+ # False: if the previous condition was False
1274
+ # then the And will be False and if the previous
1275
+ # condition is True then then we wouldn't get to
1276
+ # this point. In either case, we can skip this condition.
1277
+ for i in ([cond] +
1278
+ (list(cond.args) if isinstance(cond, And) else
1279
+ [])):
1280
+ if i in current_cond:
1281
+ got = True
1282
+ break
1283
+ if got:
1284
+ continue
1285
+
1286
+ # -- if not(c) is already in current_cond then c is
1287
+ # a redundant condition in an And. This does not
1288
+ # apply to Or, however: (e1, c), (e2, Or(~c, d))
1289
+ # is not (e1, c), (e2, d) because if c and d are
1290
+ # both False this would give no results when the
1291
+ # true answer should be (e2, True)
1292
+ if isinstance(cond, And):
1293
+ nonredundant = []
1294
+ for c in cond.args:
1295
+ if isinstance(c, Relational):
1296
+ if c.negated.canonical in current_cond:
1297
+ continue
1298
+ # if a strict inequality appears after
1299
+ # a non-strict one, then the condition is
1300
+ # redundant
1301
+ if isinstance(c, (Lt, Gt)) and (
1302
+ c.weak in current_cond):
1303
+ cond = False
1304
+ break
1305
+ nonredundant.append(c)
1306
+ else:
1307
+ cond = cond.func(*nonredundant)
1308
+ elif isinstance(cond, Relational):
1309
+ if cond.negated.canonical in current_cond:
1310
+ cond = S.true
1311
+
1312
+ current_cond.add(cond)
1313
+
1314
+ # collect successive e,c pairs when exprs or cond match
1315
+ if newargs:
1316
+ if newargs[-1].expr == expr:
1317
+ orcond = Or(cond, newargs[-1].cond)
1318
+ if isinstance(orcond, (And, Or)):
1319
+ orcond = distribute_and_over_or(orcond)
1320
+ newargs[-1] = ExprCondPair(expr, orcond)
1321
+ continue
1322
+ elif newargs[-1].cond == cond:
1323
+ continue
1324
+ newargs.append(ExprCondPair(expr, cond))
1325
+ return newargs
1326
+
1327
+
1328
+ _blessed = lambda e: getattr(e.lhs, '_diff_wrt', False) and (
1329
+ getattr(e.rhs, '_diff_wrt', None) or
1330
+ isinstance(e.rhs, (Rational, NumberSymbol)))
1331
+
1332
+
1333
+ def piecewise_simplify(expr, **kwargs):
1334
+ expr = piecewise_simplify_arguments(expr, **kwargs)
1335
+ if not isinstance(expr, Piecewise):
1336
+ return expr
1337
+ args = list(expr.args)
1338
+
1339
+ args = _piecewise_simplify_eq_and(args)
1340
+ args = _piecewise_simplify_equal_to_next_segment(args)
1341
+ return Piecewise(*args)
1342
+
1343
+
1344
+ def _piecewise_simplify_equal_to_next_segment(args):
1345
+ """
1346
+ See if expressions valid for an Equal expression happens to evaluate
1347
+ to the same function as in the next piecewise segment, see:
1348
+ https://github.com/sympy/sympy/issues/8458
1349
+ """
1350
+ prevexpr = None
1351
+ for i, (expr, cond) in reversed(list(enumerate(args))):
1352
+ if prevexpr is not None:
1353
+ if isinstance(cond, And):
1354
+ eqs, other = sift(cond.args,
1355
+ lambda i: isinstance(i, Eq), binary=True)
1356
+ elif isinstance(cond, Eq):
1357
+ eqs, other = [cond], []
1358
+ else:
1359
+ eqs = other = []
1360
+ _prevexpr = prevexpr
1361
+ _expr = expr
1362
+ if eqs and not other:
1363
+ eqs = list(ordered(eqs))
1364
+ for e in eqs:
1365
+ # allow 2 args to collapse into 1 for any e
1366
+ # otherwise limit simplification to only simple-arg
1367
+ # Eq instances
1368
+ if len(args) == 2 or _blessed(e):
1369
+ _prevexpr = _prevexpr.subs(*e.args)
1370
+ _expr = _expr.subs(*e.args)
1371
+ # Did it evaluate to the same?
1372
+ if _prevexpr == _expr:
1373
+ # Set the expression for the Not equal section to the same
1374
+ # as the next. These will be merged when creating the new
1375
+ # Piecewise
1376
+ args[i] = args[i].func(args[i + 1][0], cond)
1377
+ else:
1378
+ # Update the expression that we compare against
1379
+ prevexpr = expr
1380
+ else:
1381
+ prevexpr = expr
1382
+ return args
1383
+
1384
+
1385
+ def _piecewise_simplify_eq_and(args):
1386
+ """
1387
+ Try to simplify conditions and the expression for
1388
+ equalities that are part of the condition, e.g.
1389
+ Piecewise((n, And(Eq(n,0), Eq(n + m, 0))), (1, True))
1390
+ -> Piecewise((0, And(Eq(n, 0), Eq(m, 0))), (1, True))
1391
+ """
1392
+ for i, (expr, cond) in enumerate(args):
1393
+ if isinstance(cond, And):
1394
+ eqs, other = sift(cond.args,
1395
+ lambda i: isinstance(i, Eq), binary=True)
1396
+ elif isinstance(cond, Eq):
1397
+ eqs, other = [cond], []
1398
+ else:
1399
+ eqs = other = []
1400
+ if eqs:
1401
+ eqs = list(ordered(eqs))
1402
+ for j, e in enumerate(eqs):
1403
+ # these blessed lhs objects behave like Symbols
1404
+ # and the rhs are simple replacements for the "symbols"
1405
+ if _blessed(e):
1406
+ expr = expr.subs(*e.args)
1407
+ eqs[j + 1:] = [ei.subs(*e.args) for ei in eqs[j + 1:]]
1408
+ other = [ei.subs(*e.args) for ei in other]
1409
+ cond = And(*(eqs + other))
1410
+ args[i] = args[i].func(expr, cond)
1411
+ return args
1412
+
1413
+
1414
+ def piecewise_exclusive(expr, *, skip_nan=False, deep=True):
1415
+ """
1416
+ Rewrite :class:`Piecewise` with mutually exclusive conditions.
1417
+
1418
+ Explanation
1419
+ ===========
1420
+
1421
+ SymPy represents the conditions of a :class:`Piecewise` in an
1422
+ "if-elif"-fashion, allowing more than one condition to be simultaneously
1423
+ True. The interpretation is that the first condition that is True is the
1424
+ case that holds. While this is a useful representation computationally it
1425
+ is not how a piecewise formula is typically shown in a mathematical text.
1426
+ The :func:`piecewise_exclusive` function can be used to rewrite any
1427
+ :class:`Piecewise` with more typical mutually exclusive conditions.
1428
+
1429
+ Note that further manipulation of the resulting :class:`Piecewise`, e.g.
1430
+ simplifying it, will most likely make it non-exclusive. Hence, this is
1431
+ primarily a function to be used in conjunction with printing the Piecewise
1432
+ or if one would like to reorder the expression-condition pairs.
1433
+
1434
+ If it is not possible to determine that all possibilities are covered by
1435
+ the different cases of the :class:`Piecewise` then a final
1436
+ :class:`~sympy.core.numbers.NaN` case will be included explicitly. This
1437
+ can be prevented by passing ``skip_nan=True``.
1438
+
1439
+ Examples
1440
+ ========
1441
+
1442
+ >>> from sympy import piecewise_exclusive, Symbol, Piecewise, S
1443
+ >>> x = Symbol('x', real=True)
1444
+ >>> p = Piecewise((0, x < 0), (S.Half, x <= 0), (1, True))
1445
+ >>> piecewise_exclusive(p)
1446
+ Piecewise((0, x < 0), (1/2, Eq(x, 0)), (1, x > 0))
1447
+ >>> piecewise_exclusive(Piecewise((2, x > 1)))
1448
+ Piecewise((2, x > 1), (nan, x <= 1))
1449
+ >>> piecewise_exclusive(Piecewise((2, x > 1)), skip_nan=True)
1450
+ Piecewise((2, x > 1))
1451
+
1452
+ Parameters
1453
+ ==========
1454
+
1455
+ expr: a SymPy expression.
1456
+ Any :class:`Piecewise` in the expression will be rewritten.
1457
+ skip_nan: ``bool`` (default ``False``)
1458
+ If ``skip_nan`` is set to ``True`` then a final
1459
+ :class:`~sympy.core.numbers.NaN` case will not be included.
1460
+ deep: ``bool`` (default ``True``)
1461
+ If ``deep`` is ``True`` then :func:`piecewise_exclusive` will rewrite
1462
+ any :class:`Piecewise` subexpressions in ``expr`` rather than just
1463
+ rewriting ``expr`` itself.
1464
+
1465
+ Returns
1466
+ =======
1467
+
1468
+ An expression equivalent to ``expr`` but where all :class:`Piecewise` have
1469
+ been rewritten with mutually exclusive conditions.
1470
+
1471
+ See Also
1472
+ ========
1473
+
1474
+ Piecewise
1475
+ piecewise_fold
1476
+ """
1477
+
1478
+ def make_exclusive(*pwargs):
1479
+
1480
+ cumcond = false
1481
+ newargs = []
1482
+
1483
+ # Handle the first n-1 cases
1484
+ for expr_i, cond_i in pwargs[:-1]:
1485
+ cancond = And(cond_i, Not(cumcond)).simplify()
1486
+ cumcond = Or(cond_i, cumcond).simplify()
1487
+ newargs.append((expr_i, cancond))
1488
+
1489
+ # For the nth case defer simplification of cumcond
1490
+ expr_n, cond_n = pwargs[-1]
1491
+ cancond_n = And(cond_n, Not(cumcond)).simplify()
1492
+ newargs.append((expr_n, cancond_n))
1493
+
1494
+ if not skip_nan:
1495
+ cumcond = Or(cond_n, cumcond).simplify()
1496
+ if cumcond is not true:
1497
+ newargs.append((Undefined, Not(cumcond).simplify()))
1498
+
1499
+ return Piecewise(*newargs, evaluate=False)
1500
+
1501
+ if deep:
1502
+ return expr.replace(Piecewise, make_exclusive)
1503
+ elif isinstance(expr, Piecewise):
1504
+ return make_exclusive(*expr.args)
1505
+ else:
1506
+ return expr
venv/lib/python3.10/site-packages/sympy/functions/elementary/tests/test_complexes.py ADDED
@@ -0,0 +1,1018 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ from sympy.core.expr import Expr
2
+ from sympy.core.function import (Derivative, Function, Lambda, expand)
3
+ from sympy.core.numbers import (E, I, Rational, comp, nan, oo, pi, zoo)
4
+ from sympy.core.relational import Eq
5
+ from sympy.core.singleton import S
6
+ from sympy.core.symbol import (Symbol, symbols)
7
+ from sympy.functions.elementary.complexes import (Abs, adjoint, arg, conjugate, im, re, sign, transpose)
8
+ from sympy.functions.elementary.exponential import (exp, exp_polar, log)
9
+ from sympy.functions.elementary.miscellaneous import sqrt
10
+ from sympy.functions.elementary.piecewise import Piecewise
11
+ from sympy.functions.elementary.trigonometric import (acos, atan, atan2, cos, sin)
12
+ from sympy.functions.special.delta_functions import (DiracDelta, Heaviside)
13
+ from sympy.integrals.integrals import Integral
14
+ from sympy.matrices.dense import Matrix
15
+ from sympy.matrices.expressions.funcmatrix import FunctionMatrix
16
+ from sympy.matrices.expressions.matexpr import MatrixSymbol
17
+ from sympy.matrices.immutable import (ImmutableMatrix, ImmutableSparseMatrix)
18
+ from sympy.matrices import SparseMatrix
19
+ from sympy.sets.sets import Interval
20
+ from sympy.core.expr import unchanged
21
+ from sympy.core.function import ArgumentIndexError
22
+ from sympy.testing.pytest import XFAIL, raises, _both_exp_pow
23
+
24
+
25
+ def N_equals(a, b):
26
+ """Check whether two complex numbers are numerically close"""
27
+ return comp(a.n(), b.n(), 1.e-6)
28
+
29
+
30
+ def test_re():
31
+ x, y = symbols('x,y')
32
+ a, b = symbols('a,b', real=True)
33
+
34
+ r = Symbol('r', real=True)
35
+ i = Symbol('i', imaginary=True)
36
+
37
+ assert re(nan) is nan
38
+
39
+ assert re(oo) is oo
40
+ assert re(-oo) is -oo
41
+
42
+ assert re(0) == 0
43
+
44
+ assert re(1) == 1
45
+ assert re(-1) == -1
46
+
47
+ assert re(E) == E
48
+ assert re(-E) == -E
49
+
50
+ assert unchanged(re, x)
51
+ assert re(x*I) == -im(x)
52
+ assert re(r*I) == 0
53
+ assert re(r) == r
54
+ assert re(i*I) == I * i
55
+ assert re(i) == 0
56
+
57
+ assert re(x + y) == re(x) + re(y)
58
+ assert re(x + r) == re(x) + r
59
+
60
+ assert re(re(x)) == re(x)
61
+
62
+ assert re(2 + I) == 2
63
+ assert re(x + I) == re(x)
64
+
65
+ assert re(x + y*I) == re(x) - im(y)
66
+ assert re(x + r*I) == re(x)
67
+
68
+ assert re(log(2*I)) == log(2)
69
+
70
+ assert re((2 + I)**2).expand(complex=True) == 3
71
+
72
+ assert re(conjugate(x)) == re(x)
73
+ assert conjugate(re(x)) == re(x)
74
+
75
+ assert re(x).as_real_imag() == (re(x), 0)
76
+
77
+ assert re(i*r*x).diff(r) == re(i*x)
78
+ assert re(i*r*x).diff(i) == I*r*im(x)
79
+
80
+ assert re(
81
+ sqrt(a + b*I)) == (a**2 + b**2)**Rational(1, 4)*cos(atan2(b, a)/2)
82
+ assert re(a * (2 + b*I)) == 2*a
83
+
84
+ assert re((1 + sqrt(a + b*I))/2) == \
85
+ (a**2 + b**2)**Rational(1, 4)*cos(atan2(b, a)/2)/2 + S.Half
86
+
87
+ assert re(x).rewrite(im) == x - S.ImaginaryUnit*im(x)
88
+ assert (x + re(y)).rewrite(re, im) == x + y - S.ImaginaryUnit*im(y)
89
+
90
+ a = Symbol('a', algebraic=True)
91
+ t = Symbol('t', transcendental=True)
92
+ x = Symbol('x')
93
+ assert re(a).is_algebraic
94
+ assert re(x).is_algebraic is None
95
+ assert re(t).is_algebraic is False
96
+
97
+ assert re(S.ComplexInfinity) is S.NaN
98
+
99
+ n, m, l = symbols('n m l')
100
+ A = MatrixSymbol('A',n,m)
101
+ assert re(A) == (S.Half) * (A + conjugate(A))
102
+
103
+ A = Matrix([[1 + 4*I,2],[0, -3*I]])
104
+ assert re(A) == Matrix([[1, 2],[0, 0]])
105
+
106
+ A = ImmutableMatrix([[1 + 3*I, 3-2*I],[0, 2*I]])
107
+ assert re(A) == ImmutableMatrix([[1, 3],[0, 0]])
108
+
109
+ X = SparseMatrix([[2*j + i*I for i in range(5)] for j in range(5)])
110
+ assert re(X) - Matrix([[0, 0, 0, 0, 0],
111
+ [2, 2, 2, 2, 2],
112
+ [4, 4, 4, 4, 4],
113
+ [6, 6, 6, 6, 6],
114
+ [8, 8, 8, 8, 8]]) == Matrix.zeros(5)
115
+
116
+ assert im(X) - Matrix([[0, 1, 2, 3, 4],
117
+ [0, 1, 2, 3, 4],
118
+ [0, 1, 2, 3, 4],
119
+ [0, 1, 2, 3, 4],
120
+ [0, 1, 2, 3, 4]]) == Matrix.zeros(5)
121
+
122
+ X = FunctionMatrix(3, 3, Lambda((n, m), n + m*I))
123
+ assert re(X) == Matrix([[0, 0, 0], [1, 1, 1], [2, 2, 2]])
124
+
125
+
126
+ def test_im():
127
+ x, y = symbols('x,y')
128
+ a, b = symbols('a,b', real=True)
129
+
130
+ r = Symbol('r', real=True)
131
+ i = Symbol('i', imaginary=True)
132
+
133
+ assert im(nan) is nan
134
+
135
+ assert im(oo*I) is oo
136
+ assert im(-oo*I) is -oo
137
+
138
+ assert im(0) == 0
139
+
140
+ assert im(1) == 0
141
+ assert im(-1) == 0
142
+
143
+ assert im(E*I) == E
144
+ assert im(-E*I) == -E
145
+
146
+ assert unchanged(im, x)
147
+ assert im(x*I) == re(x)
148
+ assert im(r*I) == r
149
+ assert im(r) == 0
150
+ assert im(i*I) == 0
151
+ assert im(i) == -I * i
152
+
153
+ assert im(x + y) == im(x) + im(y)
154
+ assert im(x + r) == im(x)
155
+ assert im(x + r*I) == im(x) + r
156
+
157
+ assert im(im(x)*I) == im(x)
158
+
159
+ assert im(2 + I) == 1
160
+ assert im(x + I) == im(x) + 1
161
+
162
+ assert im(x + y*I) == im(x) + re(y)
163
+ assert im(x + r*I) == im(x) + r
164
+
165
+ assert im(log(2*I)) == pi/2
166
+
167
+ assert im((2 + I)**2).expand(complex=True) == 4
168
+
169
+ assert im(conjugate(x)) == -im(x)
170
+ assert conjugate(im(x)) == im(x)
171
+
172
+ assert im(x).as_real_imag() == (im(x), 0)
173
+
174
+ assert im(i*r*x).diff(r) == im(i*x)
175
+ assert im(i*r*x).diff(i) == -I * re(r*x)
176
+
177
+ assert im(
178
+ sqrt(a + b*I)) == (a**2 + b**2)**Rational(1, 4)*sin(atan2(b, a)/2)
179
+ assert im(a * (2 + b*I)) == a*b
180
+
181
+ assert im((1 + sqrt(a + b*I))/2) == \
182
+ (a**2 + b**2)**Rational(1, 4)*sin(atan2(b, a)/2)/2
183
+
184
+ assert im(x).rewrite(re) == -S.ImaginaryUnit * (x - re(x))
185
+ assert (x + im(y)).rewrite(im, re) == x - S.ImaginaryUnit * (y - re(y))
186
+
187
+ a = Symbol('a', algebraic=True)
188
+ t = Symbol('t', transcendental=True)
189
+ x = Symbol('x')
190
+ assert re(a).is_algebraic
191
+ assert re(x).is_algebraic is None
192
+ assert re(t).is_algebraic is False
193
+
194
+ assert im(S.ComplexInfinity) is S.NaN
195
+
196
+ n, m, l = symbols('n m l')
197
+ A = MatrixSymbol('A',n,m)
198
+
199
+ assert im(A) == (S.One/(2*I)) * (A - conjugate(A))
200
+
201
+ A = Matrix([[1 + 4*I, 2],[0, -3*I]])
202
+ assert im(A) == Matrix([[4, 0],[0, -3]])
203
+
204
+ A = ImmutableMatrix([[1 + 3*I, 3-2*I],[0, 2*I]])
205
+ assert im(A) == ImmutableMatrix([[3, -2],[0, 2]])
206
+
207
+ X = ImmutableSparseMatrix(
208
+ [[i*I + i for i in range(5)] for i in range(5)])
209
+ Y = SparseMatrix([list(range(5)) for i in range(5)])
210
+ assert im(X).as_immutable() == Y
211
+
212
+ X = FunctionMatrix(3, 3, Lambda((n, m), n + m*I))
213
+ assert im(X) == Matrix([[0, 1, 2], [0, 1, 2], [0, 1, 2]])
214
+
215
+ def test_sign():
216
+ assert sign(1.2) == 1
217
+ assert sign(-1.2) == -1
218
+ assert sign(3*I) == I
219
+ assert sign(-3*I) == -I
220
+ assert sign(0) == 0
221
+ assert sign(0, evaluate=False).doit() == 0
222
+ assert sign(oo, evaluate=False).doit() == 1
223
+ assert sign(nan) is nan
224
+ assert sign(2 + 2*I).doit() == sqrt(2)*(2 + 2*I)/4
225
+ assert sign(2 + 3*I).simplify() == sign(2 + 3*I)
226
+ assert sign(2 + 2*I).simplify() == sign(1 + I)
227
+ assert sign(im(sqrt(1 - sqrt(3)))) == 1
228
+ assert sign(sqrt(1 - sqrt(3))) == I
229
+
230
+ x = Symbol('x')
231
+ assert sign(x).is_finite is True
232
+ assert sign(x).is_complex is True
233
+ assert sign(x).is_imaginary is None
234
+ assert sign(x).is_integer is None
235
+ assert sign(x).is_real is None
236
+ assert sign(x).is_zero is None
237
+ assert sign(x).doit() == sign(x)
238
+ assert sign(1.2*x) == sign(x)
239
+ assert sign(2*x) == sign(x)
240
+ assert sign(I*x) == I*sign(x)
241
+ assert sign(-2*I*x) == -I*sign(x)
242
+ assert sign(conjugate(x)) == conjugate(sign(x))
243
+
244
+ p = Symbol('p', positive=True)
245
+ n = Symbol('n', negative=True)
246
+ m = Symbol('m', negative=True)
247
+ assert sign(2*p*x) == sign(x)
248
+ assert sign(n*x) == -sign(x)
249
+ assert sign(n*m*x) == sign(x)
250
+
251
+ x = Symbol('x', imaginary=True)
252
+ assert sign(x).is_imaginary is True
253
+ assert sign(x).is_integer is False
254
+ assert sign(x).is_real is False
255
+ assert sign(x).is_zero is False
256
+ assert sign(x).diff(x) == 2*DiracDelta(-I*x)
257
+ assert sign(x).doit() == x / Abs(x)
258
+ assert conjugate(sign(x)) == -sign(x)
259
+
260
+ x = Symbol('x', real=True)
261
+ assert sign(x).is_imaginary is False
262
+ assert sign(x).is_integer is True
263
+ assert sign(x).is_real is True
264
+ assert sign(x).is_zero is None
265
+ assert sign(x).diff(x) == 2*DiracDelta(x)
266
+ assert sign(x).doit() == sign(x)
267
+ assert conjugate(sign(x)) == sign(x)
268
+
269
+ x = Symbol('x', nonzero=True)
270
+ assert sign(x).is_imaginary is False
271
+ assert sign(x).is_integer is True
272
+ assert sign(x).is_real is True
273
+ assert sign(x).is_zero is False
274
+ assert sign(x).doit() == x / Abs(x)
275
+ assert sign(Abs(x)) == 1
276
+ assert Abs(sign(x)) == 1
277
+
278
+ x = Symbol('x', positive=True)
279
+ assert sign(x).is_imaginary is False
280
+ assert sign(x).is_integer is True
281
+ assert sign(x).is_real is True
282
+ assert sign(x).is_zero is False
283
+ assert sign(x).doit() == x / Abs(x)
284
+ assert sign(Abs(x)) == 1
285
+ assert Abs(sign(x)) == 1
286
+
287
+ x = 0
288
+ assert sign(x).is_imaginary is False
289
+ assert sign(x).is_integer is True
290
+ assert sign(x).is_real is True
291
+ assert sign(x).is_zero is True
292
+ assert sign(x).doit() == 0
293
+ assert sign(Abs(x)) == 0
294
+ assert Abs(sign(x)) == 0
295
+
296
+ nz = Symbol('nz', nonzero=True, integer=True)
297
+ assert sign(nz).is_imaginary is False
298
+ assert sign(nz).is_integer is True
299
+ assert sign(nz).is_real is True
300
+ assert sign(nz).is_zero is False
301
+ assert sign(nz)**2 == 1
302
+ assert (sign(nz)**3).args == (sign(nz), 3)
303
+
304
+ assert sign(Symbol('x', nonnegative=True)).is_nonnegative
305
+ assert sign(Symbol('x', nonnegative=True)).is_nonpositive is None
306
+ assert sign(Symbol('x', nonpositive=True)).is_nonnegative is None
307
+ assert sign(Symbol('x', nonpositive=True)).is_nonpositive
308
+ assert sign(Symbol('x', real=True)).is_nonnegative is None
309
+ assert sign(Symbol('x', real=True)).is_nonpositive is None
310
+ assert sign(Symbol('x', real=True, zero=False)).is_nonpositive is None
311
+
312
+ x, y = Symbol('x', real=True), Symbol('y')
313
+ f = Function('f')
314
+ assert sign(x).rewrite(Piecewise) == \
315
+ Piecewise((1, x > 0), (-1, x < 0), (0, True))
316
+ assert sign(y).rewrite(Piecewise) == sign(y)
317
+ assert sign(x).rewrite(Heaviside) == 2*Heaviside(x, H0=S(1)/2) - 1
318
+ assert sign(y).rewrite(Heaviside) == sign(y)
319
+ assert sign(y).rewrite(Abs) == Piecewise((0, Eq(y, 0)), (y/Abs(y), True))
320
+ assert sign(f(y)).rewrite(Abs) == Piecewise((0, Eq(f(y), 0)), (f(y)/Abs(f(y)), True))
321
+
322
+ # evaluate what can be evaluated
323
+ assert sign(exp_polar(I*pi)*pi) is S.NegativeOne
324
+
325
+ eq = -sqrt(10 + 6*sqrt(3)) + sqrt(1 + sqrt(3)) + sqrt(3 + 3*sqrt(3))
326
+ # if there is a fast way to know when and when you cannot prove an
327
+ # expression like this is zero then the equality to zero is ok
328
+ assert sign(eq).func is sign or sign(eq) == 0
329
+ # but sometimes it's hard to do this so it's better not to load
330
+ # abs down with tests that will be very slow
331
+ q = 1 + sqrt(2) - 2*sqrt(3) + 1331*sqrt(6)
332
+ p = expand(q**3)**Rational(1, 3)
333
+ d = p - q
334
+ assert sign(d).func is sign or sign(d) == 0
335
+
336
+
337
+ def test_as_real_imag():
338
+ n = pi**1000
339
+ # the special code for working out the real
340
+ # and complex parts of a power with Integer exponent
341
+ # should not run if there is no imaginary part, hence
342
+ # this should not hang
343
+ assert n.as_real_imag() == (n, 0)
344
+
345
+ # issue 6261
346
+ x = Symbol('x')
347
+ assert sqrt(x).as_real_imag() == \
348
+ ((re(x)**2 + im(x)**2)**Rational(1, 4)*cos(atan2(im(x), re(x))/2),
349
+ (re(x)**2 + im(x)**2)**Rational(1, 4)*sin(atan2(im(x), re(x))/2))
350
+
351
+ # issue 3853
352
+ a, b = symbols('a,b', real=True)
353
+ assert ((1 + sqrt(a + b*I))/2).as_real_imag() == \
354
+ (
355
+ (a**2 + b**2)**Rational(
356
+ 1, 4)*cos(atan2(b, a)/2)/2 + S.Half,
357
+ (a**2 + b**2)**Rational(1, 4)*sin(atan2(b, a)/2)/2)
358
+
359
+ assert sqrt(a**2).as_real_imag() == (sqrt(a**2), 0)
360
+ i = symbols('i', imaginary=True)
361
+ assert sqrt(i**2).as_real_imag() == (0, abs(i))
362
+
363
+ assert ((1 + I)/(1 - I)).as_real_imag() == (0, 1)
364
+ assert ((1 + I)**3/(1 - I)).as_real_imag() == (-2, 0)
365
+
366
+
367
+ @XFAIL
368
+ def test_sign_issue_3068():
369
+ n = pi**1000
370
+ i = int(n)
371
+ x = Symbol('x')
372
+ assert (n - i).round() == 1 # doesn't hang
373
+ assert sign(n - i) == 1
374
+ # perhaps it's not possible to get the sign right when
375
+ # only 1 digit is being requested for this situation;
376
+ # 2 digits works
377
+ assert (n - x).n(1, subs={x: i}) > 0
378
+ assert (n - x).n(2, subs={x: i}) > 0
379
+
380
+
381
+ def test_Abs():
382
+ raises(TypeError, lambda: Abs(Interval(2, 3))) # issue 8717
383
+
384
+ x, y = symbols('x,y')
385
+ assert sign(sign(x)) == sign(x)
386
+ assert sign(x*y).func is sign
387
+ assert Abs(0) == 0
388
+ assert Abs(1) == 1
389
+ assert Abs(-1) == 1
390
+ assert Abs(I) == 1
391
+ assert Abs(-I) == 1
392
+ assert Abs(nan) is nan
393
+ assert Abs(zoo) is oo
394
+ assert Abs(I * pi) == pi
395
+ assert Abs(-I * pi) == pi
396
+ assert Abs(I * x) == Abs(x)
397
+ assert Abs(-I * x) == Abs(x)
398
+ assert Abs(-2*x) == 2*Abs(x)
399
+ assert Abs(-2.0*x) == 2.0*Abs(x)
400
+ assert Abs(2*pi*x*y) == 2*pi*Abs(x*y)
401
+ assert Abs(conjugate(x)) == Abs(x)
402
+ assert conjugate(Abs(x)) == Abs(x)
403
+ assert Abs(x).expand(complex=True) == sqrt(re(x)**2 + im(x)**2)
404
+
405
+ a = Symbol('a', positive=True)
406
+ assert Abs(2*pi*x*a) == 2*pi*a*Abs(x)
407
+ assert Abs(2*pi*I*x*a) == 2*pi*a*Abs(x)
408
+
409
+ x = Symbol('x', real=True)
410
+ n = Symbol('n', integer=True)
411
+ assert Abs((-1)**n) == 1
412
+ assert x**(2*n) == Abs(x)**(2*n)
413
+ assert Abs(x).diff(x) == sign(x)
414
+ assert abs(x) == Abs(x) # Python built-in
415
+ assert Abs(x)**3 == x**2*Abs(x)
416
+ assert Abs(x)**4 == x**4
417
+ assert (
418
+ Abs(x)**(3*n)).args == (Abs(x), 3*n) # leave symbolic odd unchanged
419
+ assert (1/Abs(x)).args == (Abs(x), -1)
420
+ assert 1/Abs(x)**3 == 1/(x**2*Abs(x))
421
+ assert Abs(x)**-3 == Abs(x)/(x**4)
422
+ assert Abs(x**3) == x**2*Abs(x)
423
+ assert Abs(I**I) == exp(-pi/2)
424
+ assert Abs((4 + 5*I)**(6 + 7*I)) == 68921*exp(-7*atan(Rational(5, 4)))
425
+ y = Symbol('y', real=True)
426
+ assert Abs(I**y) == 1
427
+ y = Symbol('y')
428
+ assert Abs(I**y) == exp(-pi*im(y)/2)
429
+
430
+ x = Symbol('x', imaginary=True)
431
+ assert Abs(x).diff(x) == -sign(x)
432
+
433
+ eq = -sqrt(10 + 6*sqrt(3)) + sqrt(1 + sqrt(3)) + sqrt(3 + 3*sqrt(3))
434
+ # if there is a fast way to know when you can and when you cannot prove an
435
+ # expression like this is zero then the equality to zero is ok
436
+ assert abs(eq).func is Abs or abs(eq) == 0
437
+ # but sometimes it's hard to do this so it's better not to load
438
+ # abs down with tests that will be very slow
439
+ q = 1 + sqrt(2) - 2*sqrt(3) + 1331*sqrt(6)
440
+ p = expand(q**3)**Rational(1, 3)
441
+ d = p - q
442
+ assert abs(d).func is Abs or abs(d) == 0
443
+
444
+ assert Abs(4*exp(pi*I/4)) == 4
445
+ assert Abs(3**(2 + I)) == 9
446
+ assert Abs((-3)**(1 - I)) == 3*exp(pi)
447
+
448
+ assert Abs(oo) is oo
449
+ assert Abs(-oo) is oo
450
+ assert Abs(oo + I) is oo
451
+ assert Abs(oo + I*oo) is oo
452
+
453
+ a = Symbol('a', algebraic=True)
454
+ t = Symbol('t', transcendental=True)
455
+ x = Symbol('x')
456
+ assert re(a).is_algebraic
457
+ assert re(x).is_algebraic is None
458
+ assert re(t).is_algebraic is False
459
+ assert Abs(x).fdiff() == sign(x)
460
+ raises(ArgumentIndexError, lambda: Abs(x).fdiff(2))
461
+
462
+ # doesn't have recursion error
463
+ arg = sqrt(acos(1 - I)*acos(1 + I))
464
+ assert abs(arg) == arg
465
+
466
+ # special handling to put Abs in denom
467
+ assert abs(1/x) == 1/Abs(x)
468
+ e = abs(2/x**2)
469
+ assert e.is_Mul and e == 2/Abs(x**2)
470
+ assert unchanged(Abs, y/x)
471
+ assert unchanged(Abs, x/(x + 1))
472
+ assert unchanged(Abs, x*y)
473
+ p = Symbol('p', positive=True)
474
+ assert abs(x/p) == abs(x)/p
475
+
476
+ # coverage
477
+ assert unchanged(Abs, Symbol('x', real=True)**y)
478
+ # issue 19627
479
+ f = Function('f', positive=True)
480
+ assert sqrt(f(x)**2) == f(x)
481
+ # issue 21625
482
+ assert unchanged(Abs, S("im(acos(-i + acosh(-g + i)))"))
483
+
484
+
485
+ def test_Abs_rewrite():
486
+ x = Symbol('x', real=True)
487
+ a = Abs(x).rewrite(Heaviside).expand()
488
+ assert a == x*Heaviside(x) - x*Heaviside(-x)
489
+ for i in [-2, -1, 0, 1, 2]:
490
+ assert a.subs(x, i) == abs(i)
491
+ y = Symbol('y')
492
+ assert Abs(y).rewrite(Heaviside) == Abs(y)
493
+
494
+ x, y = Symbol('x', real=True), Symbol('y')
495
+ assert Abs(x).rewrite(Piecewise) == Piecewise((x, x >= 0), (-x, True))
496
+ assert Abs(y).rewrite(Piecewise) == Abs(y)
497
+ assert Abs(y).rewrite(sign) == y/sign(y)
498
+
499
+ i = Symbol('i', imaginary=True)
500
+ assert abs(i).rewrite(Piecewise) == Piecewise((I*i, I*i >= 0), (-I*i, True))
501
+
502
+
503
+ assert Abs(y).rewrite(conjugate) == sqrt(y*conjugate(y))
504
+ assert Abs(i).rewrite(conjugate) == sqrt(-i**2) # == -I*i
505
+
506
+ y = Symbol('y', extended_real=True)
507
+ assert (Abs(exp(-I*x)-exp(-I*y))**2).rewrite(conjugate) == \
508
+ -exp(I*x)*exp(-I*y) + 2 - exp(-I*x)*exp(I*y)
509
+
510
+
511
+ def test_Abs_real():
512
+ # test some properties of abs that only apply
513
+ # to real numbers
514
+ x = Symbol('x', complex=True)
515
+ assert sqrt(x**2) != Abs(x)
516
+ assert Abs(x**2) != x**2
517
+
518
+ x = Symbol('x', real=True)
519
+ assert sqrt(x**2) == Abs(x)
520
+ assert Abs(x**2) == x**2
521
+
522
+ # if the symbol is zero, the following will still apply
523
+ nn = Symbol('nn', nonnegative=True, real=True)
524
+ np = Symbol('np', nonpositive=True, real=True)
525
+ assert Abs(nn) == nn
526
+ assert Abs(np) == -np
527
+
528
+
529
+ def test_Abs_properties():
530
+ x = Symbol('x')
531
+ assert Abs(x).is_real is None
532
+ assert Abs(x).is_extended_real is True
533
+ assert Abs(x).is_rational is None
534
+ assert Abs(x).is_positive is None
535
+ assert Abs(x).is_nonnegative is None
536
+ assert Abs(x).is_extended_positive is None
537
+ assert Abs(x).is_extended_nonnegative is True
538
+
539
+ f = Symbol('x', finite=True)
540
+ assert Abs(f).is_real is True
541
+ assert Abs(f).is_extended_real is True
542
+ assert Abs(f).is_rational is None
543
+ assert Abs(f).is_positive is None
544
+ assert Abs(f).is_nonnegative is True
545
+ assert Abs(f).is_extended_positive is None
546
+ assert Abs(f).is_extended_nonnegative is True
547
+
548
+ z = Symbol('z', complex=True, zero=False)
549
+ assert Abs(z).is_real is True # since complex implies finite
550
+ assert Abs(z).is_extended_real is True
551
+ assert Abs(z).is_rational is None
552
+ assert Abs(z).is_positive is True
553
+ assert Abs(z).is_extended_positive is True
554
+ assert Abs(z).is_zero is False
555
+
556
+ p = Symbol('p', positive=True)
557
+ assert Abs(p).is_real is True
558
+ assert Abs(p).is_extended_real is True
559
+ assert Abs(p).is_rational is None
560
+ assert Abs(p).is_positive is True
561
+ assert Abs(p).is_zero is False
562
+
563
+ q = Symbol('q', rational=True)
564
+ assert Abs(q).is_real is True
565
+ assert Abs(q).is_rational is True
566
+ assert Abs(q).is_integer is None
567
+ assert Abs(q).is_positive is None
568
+ assert Abs(q).is_nonnegative is True
569
+
570
+ i = Symbol('i', integer=True)
571
+ assert Abs(i).is_real is True
572
+ assert Abs(i).is_integer is True
573
+ assert Abs(i).is_positive is None
574
+ assert Abs(i).is_nonnegative is True
575
+
576
+ e = Symbol('n', even=True)
577
+ ne = Symbol('ne', real=True, even=False)
578
+ assert Abs(e).is_even is True
579
+ assert Abs(ne).is_even is False
580
+ assert Abs(i).is_even is None
581
+
582
+ o = Symbol('n', odd=True)
583
+ no = Symbol('no', real=True, odd=False)
584
+ assert Abs(o).is_odd is True
585
+ assert Abs(no).is_odd is False
586
+ assert Abs(i).is_odd is None
587
+
588
+
589
+ def test_abs():
590
+ # this tests that abs calls Abs; don't rename to
591
+ # test_Abs since that test is already above
592
+ a = Symbol('a', positive=True)
593
+ assert abs(I*(1 + a)**2) == (1 + a)**2
594
+
595
+
596
+ def test_arg():
597
+ assert arg(0) is nan
598
+ assert arg(1) == 0
599
+ assert arg(-1) == pi
600
+ assert arg(I) == pi/2
601
+ assert arg(-I) == -pi/2
602
+ assert arg(1 + I) == pi/4
603
+ assert arg(-1 + I) == pi*Rational(3, 4)
604
+ assert arg(1 - I) == -pi/4
605
+ assert arg(exp_polar(4*pi*I)) == 4*pi
606
+ assert arg(exp_polar(-7*pi*I)) == -7*pi
607
+ assert arg(exp_polar(5 - 3*pi*I/4)) == pi*Rational(-3, 4)
608
+ f = Function('f')
609
+ assert not arg(f(0) + I*f(1)).atoms(re)
610
+
611
+ # check nesting
612
+ x = Symbol('x')
613
+ assert arg(arg(arg(x))) is not S.NaN
614
+ assert arg(arg(arg(arg(x)))) is S.NaN
615
+ r = Symbol('r', extended_real=True)
616
+ assert arg(arg(r)) is not S.NaN
617
+ assert arg(arg(arg(r))) is S.NaN
618
+
619
+ p = Function('p', extended_positive=True)
620
+ assert arg(p(x)) == 0
621
+ assert arg((3 + I)*p(x)) == arg(3 + I)
622
+
623
+ p = Symbol('p', positive=True)
624
+ assert arg(p) == 0
625
+ assert arg(p*I) == pi/2
626
+
627
+ n = Symbol('n', negative=True)
628
+ assert arg(n) == pi
629
+ assert arg(n*I) == -pi/2
630
+
631
+ x = Symbol('x')
632
+ assert conjugate(arg(x)) == arg(x)
633
+
634
+ e = p + I*p**2
635
+ assert arg(e) == arg(1 + p*I)
636
+ # make sure sign doesn't swap
637
+ e = -2*p + 4*I*p**2
638
+ assert arg(e) == arg(-1 + 2*p*I)
639
+ # make sure sign isn't lost
640
+ x = symbols('x', real=True) # could be zero
641
+ e = x + I*x
642
+ assert arg(e) == arg(x*(1 + I))
643
+ assert arg(e/p) == arg(x*(1 + I))
644
+ e = p*cos(p) + I*log(p)*exp(p)
645
+ assert arg(e).args[0] == e
646
+ # keep it simple -- let the user do more advanced cancellation
647
+ e = (p + 1) + I*(p**2 - 1)
648
+ assert arg(e).args[0] == e
649
+
650
+ f = Function('f')
651
+ e = 2*x*(f(0) - 1) - 2*x*f(0)
652
+ assert arg(e) == arg(-2*x)
653
+ assert arg(f(0)).func == arg and arg(f(0)).args == (f(0),)
654
+
655
+
656
+ def test_arg_rewrite():
657
+ assert arg(1 + I) == atan2(1, 1)
658
+
659
+ x = Symbol('x', real=True)
660
+ y = Symbol('y', real=True)
661
+ assert arg(x + I*y).rewrite(atan2) == atan2(y, x)
662
+
663
+
664
+ def test_adjoint():
665
+ a = Symbol('a', antihermitian=True)
666
+ b = Symbol('b', hermitian=True)
667
+ assert adjoint(a) == -a
668
+ assert adjoint(I*a) == I*a
669
+ assert adjoint(b) == b
670
+ assert adjoint(I*b) == -I*b
671
+ assert adjoint(a*b) == -b*a
672
+ assert adjoint(I*a*b) == I*b*a
673
+
674
+ x, y = symbols('x y')
675
+ assert adjoint(adjoint(x)) == x
676
+ assert adjoint(x + y) == adjoint(x) + adjoint(y)
677
+ assert adjoint(x - y) == adjoint(x) - adjoint(y)
678
+ assert adjoint(x * y) == adjoint(x) * adjoint(y)
679
+ assert adjoint(x / y) == adjoint(x) / adjoint(y)
680
+ assert adjoint(-x) == -adjoint(x)
681
+
682
+ x, y = symbols('x y', commutative=False)
683
+ assert adjoint(adjoint(x)) == x
684
+ assert adjoint(x + y) == adjoint(x) + adjoint(y)
685
+ assert adjoint(x - y) == adjoint(x) - adjoint(y)
686
+ assert adjoint(x * y) == adjoint(y) * adjoint(x)
687
+ assert adjoint(x / y) == 1 / adjoint(y) * adjoint(x)
688
+ assert adjoint(-x) == -adjoint(x)
689
+
690
+
691
+ def test_conjugate():
692
+ a = Symbol('a', real=True)
693
+ b = Symbol('b', imaginary=True)
694
+ assert conjugate(a) == a
695
+ assert conjugate(I*a) == -I*a
696
+ assert conjugate(b) == -b
697
+ assert conjugate(I*b) == I*b
698
+ assert conjugate(a*b) == -a*b
699
+ assert conjugate(I*a*b) == I*a*b
700
+
701
+ x, y = symbols('x y')
702
+ assert conjugate(conjugate(x)) == x
703
+ assert conjugate(x).inverse() == conjugate
704
+ assert conjugate(x + y) == conjugate(x) + conjugate(y)
705
+ assert conjugate(x - y) == conjugate(x) - conjugate(y)
706
+ assert conjugate(x * y) == conjugate(x) * conjugate(y)
707
+ assert conjugate(x / y) == conjugate(x) / conjugate(y)
708
+ assert conjugate(-x) == -conjugate(x)
709
+
710
+ a = Symbol('a', algebraic=True)
711
+ t = Symbol('t', transcendental=True)
712
+ assert re(a).is_algebraic
713
+ assert re(x).is_algebraic is None
714
+ assert re(t).is_algebraic is False
715
+
716
+
717
+ def test_conjugate_transpose():
718
+ x = Symbol('x')
719
+ assert conjugate(transpose(x)) == adjoint(x)
720
+ assert transpose(conjugate(x)) == adjoint(x)
721
+ assert adjoint(transpose(x)) == conjugate(x)
722
+ assert transpose(adjoint(x)) == conjugate(x)
723
+ assert adjoint(conjugate(x)) == transpose(x)
724
+ assert conjugate(adjoint(x)) == transpose(x)
725
+
726
+ class Symmetric(Expr):
727
+ def _eval_adjoint(self):
728
+ return None
729
+
730
+ def _eval_conjugate(self):
731
+ return None
732
+
733
+ def _eval_transpose(self):
734
+ return self
735
+ x = Symmetric()
736
+ assert conjugate(x) == adjoint(x)
737
+ assert transpose(x) == x
738
+
739
+
740
+ def test_transpose():
741
+ a = Symbol('a', complex=True)
742
+ assert transpose(a) == a
743
+ assert transpose(I*a) == I*a
744
+
745
+ x, y = symbols('x y')
746
+ assert transpose(transpose(x)) == x
747
+ assert transpose(x + y) == transpose(x) + transpose(y)
748
+ assert transpose(x - y) == transpose(x) - transpose(y)
749
+ assert transpose(x * y) == transpose(x) * transpose(y)
750
+ assert transpose(x / y) == transpose(x) / transpose(y)
751
+ assert transpose(-x) == -transpose(x)
752
+
753
+ x, y = symbols('x y', commutative=False)
754
+ assert transpose(transpose(x)) == x
755
+ assert transpose(x + y) == transpose(x) + transpose(y)
756
+ assert transpose(x - y) == transpose(x) - transpose(y)
757
+ assert transpose(x * y) == transpose(y) * transpose(x)
758
+ assert transpose(x / y) == 1 / transpose(y) * transpose(x)
759
+ assert transpose(-x) == -transpose(x)
760
+
761
+
762
+ @_both_exp_pow
763
+ def test_polarify():
764
+ from sympy.functions.elementary.complexes import (polar_lift, polarify)
765
+ x = Symbol('x')
766
+ z = Symbol('z', polar=True)
767
+ f = Function('f')
768
+ ES = {}
769
+
770
+ assert polarify(-1) == (polar_lift(-1), ES)
771
+ assert polarify(1 + I) == (polar_lift(1 + I), ES)
772
+
773
+ assert polarify(exp(x), subs=False) == exp(x)
774
+ assert polarify(1 + x, subs=False) == 1 + x
775
+ assert polarify(f(I) + x, subs=False) == f(polar_lift(I)) + x
776
+
777
+ assert polarify(x, lift=True) == polar_lift(x)
778
+ assert polarify(z, lift=True) == z
779
+ assert polarify(f(x), lift=True) == f(polar_lift(x))
780
+ assert polarify(1 + x, lift=True) == polar_lift(1 + x)
781
+ assert polarify(1 + f(x), lift=True) == polar_lift(1 + f(polar_lift(x)))
782
+
783
+ newex, subs = polarify(f(x) + z)
784
+ assert newex.subs(subs) == f(x) + z
785
+
786
+ mu = Symbol("mu")
787
+ sigma = Symbol("sigma", positive=True)
788
+
789
+ # Make sure polarify(lift=True) doesn't try to lift the integration
790
+ # variable
791
+ assert polarify(
792
+ Integral(sqrt(2)*x*exp(-(-mu + x)**2/(2*sigma**2))/(2*sqrt(pi)*sigma),
793
+ (x, -oo, oo)), lift=True) == Integral(sqrt(2)*(sigma*exp_polar(0))**exp_polar(I*pi)*
794
+ exp((sigma*exp_polar(0))**(2*exp_polar(I*pi))*exp_polar(I*pi)*polar_lift(-mu + x)**
795
+ (2*exp_polar(0))/2)*exp_polar(0)*polar_lift(x)/(2*sqrt(pi)), (x, -oo, oo))
796
+
797
+
798
+ def test_unpolarify():
799
+ from sympy.functions.elementary.complexes import (polar_lift, principal_branch, unpolarify)
800
+ from sympy.core.relational import Ne
801
+ from sympy.functions.elementary.hyperbolic import tanh
802
+ from sympy.functions.special.error_functions import erf
803
+ from sympy.functions.special.gamma_functions import (gamma, uppergamma)
804
+ from sympy.abc import x
805
+ p = exp_polar(7*I) + 1
806
+ u = exp(7*I) + 1
807
+
808
+ assert unpolarify(1) == 1
809
+ assert unpolarify(p) == u
810
+ assert unpolarify(p**2) == u**2
811
+ assert unpolarify(p**x) == p**x
812
+ assert unpolarify(p*x) == u*x
813
+ assert unpolarify(p + x) == u + x
814
+ assert unpolarify(sqrt(sin(p))) == sqrt(sin(u))
815
+
816
+ # Test reduction to principal branch 2*pi.
817
+ t = principal_branch(x, 2*pi)
818
+ assert unpolarify(t) == x
819
+ assert unpolarify(sqrt(t)) == sqrt(t)
820
+
821
+ # Test exponents_only.
822
+ assert unpolarify(p**p, exponents_only=True) == p**u
823
+ assert unpolarify(uppergamma(x, p**p)) == uppergamma(x, p**u)
824
+
825
+ # Test functions.
826
+ assert unpolarify(sin(p)) == sin(u)
827
+ assert unpolarify(tanh(p)) == tanh(u)
828
+ assert unpolarify(gamma(p)) == gamma(u)
829
+ assert unpolarify(erf(p)) == erf(u)
830
+ assert unpolarify(uppergamma(x, p)) == uppergamma(x, p)
831
+
832
+ assert unpolarify(uppergamma(sin(p), sin(p + exp_polar(0)))) == \
833
+ uppergamma(sin(u), sin(u + 1))
834
+ assert unpolarify(uppergamma(polar_lift(0), 2*exp_polar(0))) == \
835
+ uppergamma(0, 2)
836
+
837
+ assert unpolarify(Eq(p, 0)) == Eq(u, 0)
838
+ assert unpolarify(Ne(p, 0)) == Ne(u, 0)
839
+ assert unpolarify(polar_lift(x) > 0) == (x > 0)
840
+
841
+ # Test bools
842
+ assert unpolarify(True) is True
843
+
844
+
845
+ def test_issue_4035():
846
+ x = Symbol('x')
847
+ assert Abs(x).expand(trig=True) == Abs(x)
848
+ assert sign(x).expand(trig=True) == sign(x)
849
+ assert arg(x).expand(trig=True) == arg(x)
850
+
851
+
852
+ def test_issue_3206():
853
+ x = Symbol('x')
854
+ assert Abs(Abs(x)) == Abs(x)
855
+
856
+
857
+ def test_issue_4754_derivative_conjugate():
858
+ x = Symbol('x', real=True)
859
+ y = Symbol('y', imaginary=True)
860
+ f = Function('f')
861
+ assert (f(x).conjugate()).diff(x) == (f(x).diff(x)).conjugate()
862
+ assert (f(y).conjugate()).diff(y) == -(f(y).diff(y)).conjugate()
863
+
864
+
865
+ def test_derivatives_issue_4757():
866
+ x = Symbol('x', real=True)
867
+ y = Symbol('y', imaginary=True)
868
+ f = Function('f')
869
+ assert re(f(x)).diff(x) == re(f(x).diff(x))
870
+ assert im(f(x)).diff(x) == im(f(x).diff(x))
871
+ assert re(f(y)).diff(y) == -I*im(f(y).diff(y))
872
+ assert im(f(y)).diff(y) == -I*re(f(y).diff(y))
873
+ assert Abs(f(x)).diff(x).subs(f(x), 1 + I*x).doit() == x/sqrt(1 + x**2)
874
+ assert arg(f(x)).diff(x).subs(f(x), 1 + I*x**2).doit() == 2*x/(1 + x**4)
875
+ assert Abs(f(y)).diff(y).subs(f(y), 1 + y).doit() == -y/sqrt(1 - y**2)
876
+ assert arg(f(y)).diff(y).subs(f(y), I + y**2).doit() == 2*y/(1 + y**4)
877
+
878
+
879
+ def test_issue_11413():
880
+ from sympy.simplify.simplify import simplify
881
+ v0 = Symbol('v0')
882
+ v1 = Symbol('v1')
883
+ v2 = Symbol('v2')
884
+ V = Matrix([[v0],[v1],[v2]])
885
+ U = V.normalized()
886
+ assert U == Matrix([
887
+ [v0/sqrt(Abs(v0)**2 + Abs(v1)**2 + Abs(v2)**2)],
888
+ [v1/sqrt(Abs(v0)**2 + Abs(v1)**2 + Abs(v2)**2)],
889
+ [v2/sqrt(Abs(v0)**2 + Abs(v1)**2 + Abs(v2)**2)]])
890
+ U.norm = sqrt(v0**2/(v0**2 + v1**2 + v2**2) + v1**2/(v0**2 + v1**2 + v2**2) + v2**2/(v0**2 + v1**2 + v2**2))
891
+ assert simplify(U.norm) == 1
892
+
893
+
894
+ def test_periodic_argument():
895
+ from sympy.functions.elementary.complexes import (periodic_argument, polar_lift, principal_branch, unbranched_argument)
896
+ x = Symbol('x')
897
+ p = Symbol('p', positive=True)
898
+
899
+ assert unbranched_argument(2 + I) == periodic_argument(2 + I, oo)
900
+ assert unbranched_argument(1 + x) == periodic_argument(1 + x, oo)
901
+ assert N_equals(unbranched_argument((1 + I)**2), pi/2)
902
+ assert N_equals(unbranched_argument((1 - I)**2), -pi/2)
903
+ assert N_equals(periodic_argument((1 + I)**2, 3*pi), pi/2)
904
+ assert N_equals(periodic_argument((1 - I)**2, 3*pi), -pi/2)
905
+
906
+ assert unbranched_argument(principal_branch(x, pi)) == \
907
+ periodic_argument(x, pi)
908
+
909
+ assert unbranched_argument(polar_lift(2 + I)) == unbranched_argument(2 + I)
910
+ assert periodic_argument(polar_lift(2 + I), 2*pi) == \
911
+ periodic_argument(2 + I, 2*pi)
912
+ assert periodic_argument(polar_lift(2 + I), 3*pi) == \
913
+ periodic_argument(2 + I, 3*pi)
914
+ assert periodic_argument(polar_lift(2 + I), pi) == \
915
+ periodic_argument(polar_lift(2 + I), pi)
916
+
917
+ assert unbranched_argument(polar_lift(1 + I)) == pi/4
918
+ assert periodic_argument(2*p, p) == periodic_argument(p, p)
919
+ assert periodic_argument(pi*p, p) == periodic_argument(p, p)
920
+
921
+ assert Abs(polar_lift(1 + I)) == Abs(1 + I)
922
+
923
+
924
+ @XFAIL
925
+ def test_principal_branch_fail():
926
+ # TODO XXX why does abs(x)._eval_evalf() not fall back to global evalf?
927
+ from sympy.functions.elementary.complexes import principal_branch
928
+ assert N_equals(principal_branch((1 + I)**2, pi/2), 0)
929
+
930
+
931
+ def test_principal_branch():
932
+ from sympy.functions.elementary.complexes import (polar_lift, principal_branch)
933
+ p = Symbol('p', positive=True)
934
+ x = Symbol('x')
935
+ neg = Symbol('x', negative=True)
936
+
937
+ assert principal_branch(polar_lift(x), p) == principal_branch(x, p)
938
+ assert principal_branch(polar_lift(2 + I), p) == principal_branch(2 + I, p)
939
+ assert principal_branch(2*x, p) == 2*principal_branch(x, p)
940
+ assert principal_branch(1, pi) == exp_polar(0)
941
+ assert principal_branch(-1, 2*pi) == exp_polar(I*pi)
942
+ assert principal_branch(-1, pi) == exp_polar(0)
943
+ assert principal_branch(exp_polar(3*pi*I)*x, 2*pi) == \
944
+ principal_branch(exp_polar(I*pi)*x, 2*pi)
945
+ assert principal_branch(neg*exp_polar(pi*I), 2*pi) == neg*exp_polar(-I*pi)
946
+ # related to issue #14692
947
+ assert principal_branch(exp_polar(-I*pi/2)/polar_lift(neg), 2*pi) == \
948
+ exp_polar(-I*pi/2)/neg
949
+
950
+ assert N_equals(principal_branch((1 + I)**2, 2*pi), 2*I)
951
+ assert N_equals(principal_branch((1 + I)**2, 3*pi), 2*I)
952
+ assert N_equals(principal_branch((1 + I)**2, 1*pi), 2*I)
953
+
954
+ # test argument sanitization
955
+ assert principal_branch(x, I).func is principal_branch
956
+ assert principal_branch(x, -4).func is principal_branch
957
+ assert principal_branch(x, -oo).func is principal_branch
958
+ assert principal_branch(x, zoo).func is principal_branch
959
+
960
+
961
+ @XFAIL
962
+ def test_issue_6167_6151():
963
+ n = pi**1000
964
+ i = int(n)
965
+ assert sign(n - i) == 1
966
+ assert abs(n - i) == n - i
967
+ x = Symbol('x')
968
+ eps = pi**-1500
969
+ big = pi**1000
970
+ one = cos(x)**2 + sin(x)**2
971
+ e = big*one - big + eps
972
+ from sympy.simplify.simplify import simplify
973
+ assert sign(simplify(e)) == 1
974
+ for xi in (111, 11, 1, Rational(1, 10)):
975
+ assert sign(e.subs(x, xi)) == 1
976
+
977
+
978
+ def test_issue_14216():
979
+ from sympy.functions.elementary.complexes import unpolarify
980
+ A = MatrixSymbol("A", 2, 2)
981
+ assert unpolarify(A[0, 0]) == A[0, 0]
982
+ assert unpolarify(A[0, 0]*A[1, 0]) == A[0, 0]*A[1, 0]
983
+
984
+
985
+ def test_issue_14238():
986
+ # doesn't cause recursion error
987
+ r = Symbol('r', real=True)
988
+ assert Abs(r + Piecewise((0, r > 0), (1 - r, True)))
989
+
990
+
991
+ def test_issue_22189():
992
+ x = Symbol('x')
993
+ for a in (sqrt(7 - 2*x) - 2, 1 - x):
994
+ assert Abs(a) - Abs(-a) == 0, a
995
+
996
+
997
+ def test_zero_assumptions():
998
+ nr = Symbol('nonreal', real=False, finite=True)
999
+ ni = Symbol('nonimaginary', imaginary=False)
1000
+ # imaginary implies not zero
1001
+ nzni = Symbol('nonzerononimaginary', zero=False, imaginary=False)
1002
+
1003
+ assert re(nr).is_zero is None
1004
+ assert im(nr).is_zero is False
1005
+
1006
+ assert re(ni).is_zero is None
1007
+ assert im(ni).is_zero is None
1008
+
1009
+ assert re(nzni).is_zero is False
1010
+ assert im(nzni).is_zero is None
1011
+
1012
+
1013
+ @_both_exp_pow
1014
+ def test_issue_15893():
1015
+ f = Function('f', real=True)
1016
+ x = Symbol('x', real=True)
1017
+ eq = Derivative(Abs(f(x)), f(x))
1018
+ assert eq.doit() == sign(f(x))
venv/lib/python3.10/site-packages/sympy/functions/elementary/tests/test_exponential.py ADDED
@@ -0,0 +1,806 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ from sympy.assumptions.refine import refine
2
+ from sympy.calculus.accumulationbounds import AccumBounds
3
+ from sympy.concrete.products import Product
4
+ from sympy.concrete.summations import Sum
5
+ from sympy.core.function import expand_log
6
+ from sympy.core.numbers import (E, Float, I, Rational, nan, oo, pi, zoo)
7
+ from sympy.core.power import Pow
8
+ from sympy.core.singleton import S
9
+ from sympy.core.symbol import (Symbol, symbols)
10
+ from sympy.functions.elementary.complexes import (adjoint, conjugate, re, sign, transpose)
11
+ from sympy.functions.elementary.exponential import (LambertW, exp, exp_polar, log)
12
+ from sympy.functions.elementary.hyperbolic import (cosh, sinh, tanh)
13
+ from sympy.functions.elementary.miscellaneous import sqrt
14
+ from sympy.functions.elementary.trigonometric import (cos, sin, tan)
15
+ from sympy.matrices.expressions.matexpr import MatrixSymbol
16
+ from sympy.polys.polytools import gcd
17
+ from sympy.series.order import O
18
+ from sympy.simplify.simplify import simplify
19
+ from sympy.core.parameters import global_parameters
20
+ from sympy.functions.elementary.exponential import match_real_imag
21
+ from sympy.abc import x, y, z
22
+ from sympy.core.expr import unchanged
23
+ from sympy.core.function import ArgumentIndexError
24
+ from sympy.testing.pytest import raises, XFAIL, _both_exp_pow
25
+
26
+
27
+ @_both_exp_pow
28
+ def test_exp_values():
29
+ if global_parameters.exp_is_pow:
30
+ assert type(exp(x)) is Pow
31
+ else:
32
+ assert type(exp(x)) is exp
33
+
34
+ k = Symbol('k', integer=True)
35
+
36
+ assert exp(nan) is nan
37
+
38
+ assert exp(oo) is oo
39
+ assert exp(-oo) == 0
40
+
41
+ assert exp(0) == 1
42
+ assert exp(1) == E
43
+ assert exp(-1 + x).as_base_exp() == (S.Exp1, x - 1)
44
+ assert exp(1 + x).as_base_exp() == (S.Exp1, x + 1)
45
+
46
+ assert exp(pi*I/2) == I
47
+ assert exp(pi*I) == -1
48
+ assert exp(pi*I*Rational(3, 2)) == -I
49
+ assert exp(2*pi*I) == 1
50
+
51
+ assert refine(exp(pi*I*2*k)) == 1
52
+ assert refine(exp(pi*I*2*(k + S.Half))) == -1
53
+ assert refine(exp(pi*I*2*(k + Rational(1, 4)))) == I
54
+ assert refine(exp(pi*I*2*(k + Rational(3, 4)))) == -I
55
+
56
+ assert exp(log(x)) == x
57
+ assert exp(2*log(x)) == x**2
58
+ assert exp(pi*log(x)) == x**pi
59
+
60
+ assert exp(17*log(x) + E*log(y)) == x**17 * y**E
61
+
62
+ assert exp(x*log(x)) != x**x
63
+ assert exp(sin(x)*log(x)) != x
64
+
65
+ assert exp(3*log(x) + oo*x) == exp(oo*x) * x**3
66
+ assert exp(4*log(x)*log(y) + 3*log(x)) == x**3 * exp(4*log(x)*log(y))
67
+
68
+ assert exp(-oo, evaluate=False).is_finite is True
69
+ assert exp(oo, evaluate=False).is_finite is False
70
+
71
+
72
+ @_both_exp_pow
73
+ def test_exp_period():
74
+ assert exp(I*pi*Rational(9, 4)) == exp(I*pi/4)
75
+ assert exp(I*pi*Rational(46, 18)) == exp(I*pi*Rational(5, 9))
76
+ assert exp(I*pi*Rational(25, 7)) == exp(I*pi*Rational(-3, 7))
77
+ assert exp(I*pi*Rational(-19, 3)) == exp(-I*pi/3)
78
+ assert exp(I*pi*Rational(37, 8)) - exp(I*pi*Rational(-11, 8)) == 0
79
+ assert exp(I*pi*Rational(-5, 3)) / exp(I*pi*Rational(11, 5)) * exp(I*pi*Rational(148, 15)) == 1
80
+
81
+ assert exp(2 - I*pi*Rational(17, 5)) == exp(2 + I*pi*Rational(3, 5))
82
+ assert exp(log(3) + I*pi*Rational(29, 9)) == 3 * exp(I*pi*Rational(-7, 9))
83
+
84
+ n = Symbol('n', integer=True)
85
+ e = Symbol('e', even=True)
86
+ assert exp(e*I*pi) == 1
87
+ assert exp((e + 1)*I*pi) == -1
88
+ assert exp((1 + 4*n)*I*pi/2) == I
89
+ assert exp((-1 + 4*n)*I*pi/2) == -I
90
+
91
+
92
+ @_both_exp_pow
93
+ def test_exp_log():
94
+ x = Symbol("x", real=True)
95
+ assert log(exp(x)) == x
96
+ assert exp(log(x)) == x
97
+
98
+ if not global_parameters.exp_is_pow:
99
+ assert log(x).inverse() == exp
100
+ assert exp(x).inverse() == log
101
+
102
+ y = Symbol("y", polar=True)
103
+ assert log(exp_polar(z)) == z
104
+ assert exp(log(y)) == y
105
+
106
+
107
+ @_both_exp_pow
108
+ def test_exp_expand():
109
+ e = exp(log(Rational(2))*(1 + x) - log(Rational(2))*x)
110
+ assert e.expand() == 2
111
+ assert exp(x + y) != exp(x)*exp(y)
112
+ assert exp(x + y).expand() == exp(x)*exp(y)
113
+
114
+
115
+ @_both_exp_pow
116
+ def test_exp__as_base_exp():
117
+ assert exp(x).as_base_exp() == (E, x)
118
+ assert exp(2*x).as_base_exp() == (E, 2*x)
119
+ assert exp(x*y).as_base_exp() == (E, x*y)
120
+ assert exp(-x).as_base_exp() == (E, -x)
121
+
122
+ # Pow( *expr.as_base_exp() ) == expr invariant should hold
123
+ assert E**x == exp(x)
124
+ assert E**(2*x) == exp(2*x)
125
+ assert E**(x*y) == exp(x*y)
126
+
127
+ assert exp(x).base is S.Exp1
128
+ assert exp(x).exp == x
129
+
130
+
131
+ @_both_exp_pow
132
+ def test_exp_infinity():
133
+ assert exp(I*y) != nan
134
+ assert refine(exp(I*oo)) is nan
135
+ assert refine(exp(-I*oo)) is nan
136
+ assert exp(y*I*oo) != nan
137
+ assert exp(zoo) is nan
138
+ x = Symbol('x', extended_real=True, finite=False)
139
+ assert exp(x).is_complex is None
140
+
141
+
142
+ @_both_exp_pow
143
+ def test_exp_subs():
144
+ x = Symbol('x')
145
+ e = (exp(3*log(x), evaluate=False)) # evaluates to x**3
146
+ assert e.subs(x**3, y**3) == e
147
+ assert e.subs(x**2, 5) == e
148
+ assert (x**3).subs(x**2, y) != y**Rational(3, 2)
149
+ assert exp(exp(x) + exp(x**2)).subs(exp(exp(x)), y) == y * exp(exp(x**2))
150
+ assert exp(x).subs(E, y) == y**x
151
+ x = symbols('x', real=True)
152
+ assert exp(5*x).subs(exp(7*x), y) == y**Rational(5, 7)
153
+ assert exp(2*x + 7).subs(exp(3*x), y) == y**Rational(2, 3) * exp(7)
154
+ x = symbols('x', positive=True)
155
+ assert exp(3*log(x)).subs(x**2, y) == y**Rational(3, 2)
156
+ # differentiate between E and exp
157
+ assert exp(exp(x + E)).subs(exp, 3) == 3**(3**(x + E))
158
+ assert exp(exp(x + E)).subs(exp, sin) == sin(sin(x + E))
159
+ assert exp(exp(x + E)).subs(E, 3) == 3**(3**(x + 3))
160
+ assert exp(3).subs(E, sin) == sin(3)
161
+
162
+
163
+ def test_exp_adjoint():
164
+ assert adjoint(exp(x)) == exp(adjoint(x))
165
+
166
+
167
+ def test_exp_conjugate():
168
+ assert conjugate(exp(x)) == exp(conjugate(x))
169
+
170
+
171
+ @_both_exp_pow
172
+ def test_exp_transpose():
173
+ assert transpose(exp(x)) == exp(transpose(x))
174
+
175
+
176
+ @_both_exp_pow
177
+ def test_exp_rewrite():
178
+ assert exp(x).rewrite(sin) == sinh(x) + cosh(x)
179
+ assert exp(x*I).rewrite(cos) == cos(x) + I*sin(x)
180
+ assert exp(1).rewrite(cos) == sinh(1) + cosh(1)
181
+ assert exp(1).rewrite(sin) == sinh(1) + cosh(1)
182
+ assert exp(1).rewrite(sin) == sinh(1) + cosh(1)
183
+ assert exp(x).rewrite(tanh) == (1 + tanh(x/2))/(1 - tanh(x/2))
184
+ assert exp(pi*I/4).rewrite(sqrt) == sqrt(2)/2 + sqrt(2)*I/2
185
+ assert exp(pi*I/3).rewrite(sqrt) == S.Half + sqrt(3)*I/2
186
+ if not global_parameters.exp_is_pow:
187
+ assert exp(x*log(y)).rewrite(Pow) == y**x
188
+ assert exp(log(x)*log(y)).rewrite(Pow) in [x**log(y), y**log(x)]
189
+ assert exp(log(log(x))*y).rewrite(Pow) == log(x)**y
190
+
191
+ n = Symbol('n', integer=True)
192
+
193
+ assert Sum((exp(pi*I/2)/2)**n, (n, 0, oo)).rewrite(sqrt).doit() == Rational(4, 5) + I*2/5
194
+ assert Sum((exp(pi*I/4)/2)**n, (n, 0, oo)).rewrite(sqrt).doit() == 1/(1 - sqrt(2)*(1 + I)/4)
195
+ assert (Sum((exp(pi*I/3)/2)**n, (n, 0, oo)).rewrite(sqrt).doit().cancel()
196
+ == 4*I/(sqrt(3) + 3*I))
197
+
198
+
199
+ @_both_exp_pow
200
+ def test_exp_leading_term():
201
+ assert exp(x).as_leading_term(x) == 1
202
+ assert exp(2 + x).as_leading_term(x) == exp(2)
203
+ assert exp((2*x + 3) / (x+1)).as_leading_term(x) == exp(3)
204
+
205
+ # The following tests are commented, since now SymPy returns the
206
+ # original function when the leading term in the series expansion does
207
+ # not exist.
208
+ # raises(NotImplementedError, lambda: exp(1/x).as_leading_term(x))
209
+ # raises(NotImplementedError, lambda: exp((x + 1) / x**2).as_leading_term(x))
210
+ # raises(NotImplementedError, lambda: exp(x + 1/x).as_leading_term(x))
211
+
212
+
213
+ @_both_exp_pow
214
+ def test_exp_taylor_term():
215
+ x = symbols('x')
216
+ assert exp(x).taylor_term(1, x) == x
217
+ assert exp(x).taylor_term(3, x) == x**3/6
218
+ assert exp(x).taylor_term(4, x) == x**4/24
219
+ assert exp(x).taylor_term(-1, x) is S.Zero
220
+
221
+
222
+ def test_exp_MatrixSymbol():
223
+ A = MatrixSymbol("A", 2, 2)
224
+ assert exp(A).has(exp)
225
+
226
+
227
+ def test_exp_fdiff():
228
+ x = Symbol('x')
229
+ raises(ArgumentIndexError, lambda: exp(x).fdiff(2))
230
+
231
+
232
+ def test_log_values():
233
+ assert log(nan) is nan
234
+
235
+ assert log(oo) is oo
236
+ assert log(-oo) is oo
237
+
238
+ assert log(zoo) is zoo
239
+ assert log(-zoo) is zoo
240
+
241
+ assert log(0) is zoo
242
+
243
+ assert log(1) == 0
244
+ assert log(-1) == I*pi
245
+
246
+ assert log(E) == 1
247
+ assert log(-E).expand() == 1 + I*pi
248
+
249
+ assert unchanged(log, pi)
250
+ assert log(-pi).expand() == log(pi) + I*pi
251
+
252
+ assert unchanged(log, 17)
253
+ assert log(-17) == log(17) + I*pi
254
+
255
+ assert log(I) == I*pi/2
256
+ assert log(-I) == -I*pi/2
257
+
258
+ assert log(17*I) == I*pi/2 + log(17)
259
+ assert log(-17*I).expand() == -I*pi/2 + log(17)
260
+
261
+ assert log(oo*I) is oo
262
+ assert log(-oo*I) is oo
263
+ assert log(0, 2) is zoo
264
+ assert log(0, 5) is zoo
265
+
266
+ assert exp(-log(3))**(-1) == 3
267
+
268
+ assert log(S.Half) == -log(2)
269
+ assert log(2*3).func is log
270
+ assert log(2*3**2).func is log
271
+
272
+
273
+ def test_match_real_imag():
274
+ x, y = symbols('x,y', real=True)
275
+ i = Symbol('i', imaginary=True)
276
+ assert match_real_imag(S.One) == (1, 0)
277
+ assert match_real_imag(I) == (0, 1)
278
+ assert match_real_imag(3 - 5*I) == (3, -5)
279
+ assert match_real_imag(-sqrt(3) + S.Half*I) == (-sqrt(3), S.Half)
280
+ assert match_real_imag(x + y*I) == (x, y)
281
+ assert match_real_imag(x*I + y*I) == (0, x + y)
282
+ assert match_real_imag((x + y)*I) == (0, x + y)
283
+ assert match_real_imag(Rational(-2, 3)*i*I) == (None, None)
284
+ assert match_real_imag(1 - 2*i) == (None, None)
285
+ assert match_real_imag(sqrt(2)*(3 - 5*I)) == (None, None)
286
+
287
+
288
+ def test_log_exact():
289
+ # check for pi/2, pi/3, pi/4, pi/6, pi/8, pi/12; pi/5, pi/10:
290
+ for n in range(-23, 24):
291
+ if gcd(n, 24) != 1:
292
+ assert log(exp(n*I*pi/24).rewrite(sqrt)) == n*I*pi/24
293
+ for n in range(-9, 10):
294
+ assert log(exp(n*I*pi/10).rewrite(sqrt)) == n*I*pi/10
295
+
296
+ assert log(S.Half - I*sqrt(3)/2) == -I*pi/3
297
+ assert log(Rational(-1, 2) + I*sqrt(3)/2) == I*pi*Rational(2, 3)
298
+ assert log(-sqrt(2)/2 - I*sqrt(2)/2) == -I*pi*Rational(3, 4)
299
+ assert log(-sqrt(3)/2 - I*S.Half) == -I*pi*Rational(5, 6)
300
+
301
+ assert log(Rational(-1, 4) + sqrt(5)/4 - I*sqrt(sqrt(5)/8 + Rational(5, 8))) == -I*pi*Rational(2, 5)
302
+ assert log(sqrt(Rational(5, 8) - sqrt(5)/8) + I*(Rational(1, 4) + sqrt(5)/4)) == I*pi*Rational(3, 10)
303
+ assert log(-sqrt(sqrt(2)/4 + S.Half) + I*sqrt(S.Half - sqrt(2)/4)) == I*pi*Rational(7, 8)
304
+ assert log(-sqrt(6)/4 - sqrt(2)/4 + I*(-sqrt(6)/4 + sqrt(2)/4)) == -I*pi*Rational(11, 12)
305
+
306
+ assert log(-1 + I*sqrt(3)) == log(2) + I*pi*Rational(2, 3)
307
+ assert log(5 + 5*I) == log(5*sqrt(2)) + I*pi/4
308
+ assert log(sqrt(-12)) == log(2*sqrt(3)) + I*pi/2
309
+ assert log(-sqrt(6) + sqrt(2) - I*sqrt(6) - I*sqrt(2)) == log(4) - I*pi*Rational(7, 12)
310
+ assert log(-sqrt(6-3*sqrt(2)) - I*sqrt(6+3*sqrt(2))) == log(2*sqrt(3)) - I*pi*Rational(5, 8)
311
+ assert log(1 + I*sqrt(2-sqrt(2))/sqrt(2+sqrt(2))) == log(2/sqrt(sqrt(2) + 2)) + I*pi/8
312
+ assert log(cos(pi*Rational(7, 12)) + I*sin(pi*Rational(7, 12))) == I*pi*Rational(7, 12)
313
+ assert log(cos(pi*Rational(6, 5)) + I*sin(pi*Rational(6, 5))) == I*pi*Rational(-4, 5)
314
+
315
+ assert log(5*(1 + I)/sqrt(2)) == log(5) + I*pi/4
316
+ assert log(sqrt(2)*(-sqrt(3) + 1 - sqrt(3)*I - I)) == log(4) - I*pi*Rational(7, 12)
317
+ assert log(-sqrt(2)*(1 - I*sqrt(3))) == log(2*sqrt(2)) + I*pi*Rational(2, 3)
318
+ assert log(sqrt(3)*I*(-sqrt(6 - 3*sqrt(2)) - I*sqrt(3*sqrt(2) + 6))) == log(6) - I*pi/8
319
+
320
+ zero = (1 + sqrt(2))**2 - 3 - 2*sqrt(2)
321
+ assert log(zero - I*sqrt(3)) == log(sqrt(3)) - I*pi/2
322
+ assert unchanged(log, zero + I*zero) or log(zero + zero*I) is zoo
323
+
324
+ # bail quickly if no obvious simplification is possible:
325
+ assert unchanged(log, (sqrt(2)-1/sqrt(sqrt(3)+I))**1000)
326
+ # beware of non-real coefficients
327
+ assert unchanged(log, sqrt(2-sqrt(5))*(1 + I))
328
+
329
+
330
+ def test_log_base():
331
+ assert log(1, 2) == 0
332
+ assert log(2, 2) == 1
333
+ assert log(3, 2) == log(3)/log(2)
334
+ assert log(6, 2) == 1 + log(3)/log(2)
335
+ assert log(6, 3) == 1 + log(2)/log(3)
336
+ assert log(2**3, 2) == 3
337
+ assert log(3**3, 3) == 3
338
+ assert log(5, 1) is zoo
339
+ assert log(1, 1) is nan
340
+ assert log(Rational(2, 3), 10) == log(Rational(2, 3))/log(10)
341
+ assert log(Rational(2, 3), Rational(1, 3)) == -log(2)/log(3) + 1
342
+ assert log(Rational(2, 3), Rational(2, 5)) == \
343
+ log(Rational(2, 3))/log(Rational(2, 5))
344
+ # issue 17148
345
+ assert log(Rational(8, 3), 2) == -log(3)/log(2) + 3
346
+
347
+
348
+ def test_log_symbolic():
349
+ assert log(x, exp(1)) == log(x)
350
+ assert log(exp(x)) != x
351
+
352
+ assert log(x, exp(1)) == log(x)
353
+ assert log(x*y) != log(x) + log(y)
354
+ assert log(x/y).expand() != log(x) - log(y)
355
+ assert log(x/y).expand(force=True) == log(x) - log(y)
356
+ assert log(x**y).expand() != y*log(x)
357
+ assert log(x**y).expand(force=True) == y*log(x)
358
+
359
+ assert log(x, 2) == log(x)/log(2)
360
+ assert log(E, 2) == 1/log(2)
361
+
362
+ p, q = symbols('p,q', positive=True)
363
+ r = Symbol('r', real=True)
364
+
365
+ assert log(p**2) != 2*log(p)
366
+ assert log(p**2).expand() == 2*log(p)
367
+ assert log(x**2).expand() != 2*log(x)
368
+ assert log(p**q) != q*log(p)
369
+ assert log(exp(p)) == p
370
+ assert log(p*q) != log(p) + log(q)
371
+ assert log(p*q).expand() == log(p) + log(q)
372
+
373
+ assert log(-sqrt(3)) == log(sqrt(3)) + I*pi
374
+ assert log(-exp(p)) != p + I*pi
375
+ assert log(-exp(x)).expand() != x + I*pi
376
+ assert log(-exp(r)).expand() == r + I*pi
377
+
378
+ assert log(x**y) != y*log(x)
379
+
380
+ assert (log(x**-5)**-1).expand() != -1/log(x)/5
381
+ assert (log(p**-5)**-1).expand() == -1/log(p)/5
382
+ assert log(-x).func is log and log(-x).args[0] == -x
383
+ assert log(-p).func is log and log(-p).args[0] == -p
384
+
385
+
386
+ def test_log_exp():
387
+ assert log(exp(4*I*pi)) == 0 # exp evaluates
388
+ assert log(exp(-5*I*pi)) == I*pi # exp evaluates
389
+ assert log(exp(I*pi*Rational(19, 4))) == I*pi*Rational(3, 4)
390
+ assert log(exp(I*pi*Rational(25, 7))) == I*pi*Rational(-3, 7)
391
+ assert log(exp(-5*I)) == -5*I + 2*I*pi
392
+
393
+
394
+ @_both_exp_pow
395
+ def test_exp_assumptions():
396
+ r = Symbol('r', real=True)
397
+ i = Symbol('i', imaginary=True)
398
+ for e in exp, exp_polar:
399
+ assert e(x).is_real is None
400
+ assert e(x).is_imaginary is None
401
+ assert e(i).is_real is None
402
+ assert e(i).is_imaginary is None
403
+ assert e(r).is_real is True
404
+ assert e(r).is_imaginary is False
405
+ assert e(re(x)).is_extended_real is True
406
+ assert e(re(x)).is_imaginary is False
407
+
408
+ assert Pow(E, I*pi, evaluate=False).is_imaginary == False
409
+ assert Pow(E, 2*I*pi, evaluate=False).is_imaginary == False
410
+ assert Pow(E, I*pi/2, evaluate=False).is_imaginary == True
411
+ assert Pow(E, I*pi/3, evaluate=False).is_imaginary is None
412
+
413
+ assert exp(0, evaluate=False).is_algebraic
414
+
415
+ a = Symbol('a', algebraic=True)
416
+ an = Symbol('an', algebraic=True, nonzero=True)
417
+ r = Symbol('r', rational=True)
418
+ rn = Symbol('rn', rational=True, nonzero=True)
419
+ assert exp(a).is_algebraic is None
420
+ assert exp(an).is_algebraic is False
421
+ assert exp(pi*r).is_algebraic is None
422
+ assert exp(pi*rn).is_algebraic is False
423
+
424
+ assert exp(0, evaluate=False).is_algebraic is True
425
+ assert exp(I*pi/3, evaluate=False).is_algebraic is True
426
+ assert exp(I*pi*r, evaluate=False).is_algebraic is True
427
+
428
+
429
+ @_both_exp_pow
430
+ def test_exp_AccumBounds():
431
+ assert exp(AccumBounds(1, 2)) == AccumBounds(E, E**2)
432
+
433
+
434
+ def test_log_assumptions():
435
+ p = symbols('p', positive=True)
436
+ n = symbols('n', negative=True)
437
+ z = symbols('z', zero=True)
438
+ x = symbols('x', infinite=True, extended_positive=True)
439
+
440
+ assert log(z).is_positive is False
441
+ assert log(x).is_extended_positive is True
442
+ assert log(2) > 0
443
+ assert log(1, evaluate=False).is_zero
444
+ assert log(1 + z).is_zero
445
+ assert log(p).is_zero is None
446
+ assert log(n).is_zero is False
447
+ assert log(0.5).is_negative is True
448
+ assert log(exp(p) + 1).is_positive
449
+
450
+ assert log(1, evaluate=False).is_algebraic
451
+ assert log(42, evaluate=False).is_algebraic is False
452
+
453
+ assert log(1 + z).is_rational
454
+
455
+
456
+ def test_log_hashing():
457
+ assert x != log(log(x))
458
+ assert hash(x) != hash(log(log(x)))
459
+ assert log(x) != log(log(log(x)))
460
+
461
+ e = 1/log(log(x) + log(log(x)))
462
+ assert e.base.func is log
463
+ e = 1/log(log(x) + log(log(log(x))))
464
+ assert e.base.func is log
465
+
466
+ e = log(log(x))
467
+ assert e.func is log
468
+ assert x.func is not log
469
+ assert hash(log(log(x))) != hash(x)
470
+ assert e != x
471
+
472
+
473
+ def test_log_sign():
474
+ assert sign(log(2)) == 1
475
+
476
+
477
+ def test_log_expand_complex():
478
+ assert log(1 + I).expand(complex=True) == log(2)/2 + I*pi/4
479
+ assert log(1 - sqrt(2)).expand(complex=True) == log(sqrt(2) - 1) + I*pi
480
+
481
+
482
+ def test_log_apply_evalf():
483
+ value = (log(3)/log(2) - 1).evalf()
484
+ assert value.epsilon_eq(Float("0.58496250072115618145373"))
485
+
486
+
487
+ def test_log_leading_term():
488
+ p = Symbol('p')
489
+
490
+ # Test for STEP 3
491
+ assert log(1 + x + x**2).as_leading_term(x, cdir=1) == x
492
+ # Test for STEP 4
493
+ assert log(2*x).as_leading_term(x, cdir=1) == log(x) + log(2)
494
+ assert log(2*x).as_leading_term(x, cdir=-1) == log(x) + log(2)
495
+ assert log(-2*x).as_leading_term(x, cdir=1, logx=p) == p + log(2) + I*pi
496
+ assert log(-2*x).as_leading_term(x, cdir=-1, logx=p) == p + log(2) - I*pi
497
+ # Test for STEP 5
498
+ assert log(-2*x + (3 - I)*x**2).as_leading_term(x, cdir=1) == log(x) + log(2) - I*pi
499
+ assert log(-2*x + (3 - I)*x**2).as_leading_term(x, cdir=-1) == log(x) + log(2) - I*pi
500
+ assert log(2*x + (3 - I)*x**2).as_leading_term(x, cdir=1) == log(x) + log(2)
501
+ assert log(2*x + (3 - I)*x**2).as_leading_term(x, cdir=-1) == log(x) + log(2) - 2*I*pi
502
+ assert log(-1 + x - I*x**2 + I*x**3).as_leading_term(x, cdir=1) == -I*pi
503
+ assert log(-1 + x - I*x**2 + I*x**3).as_leading_term(x, cdir=-1) == -I*pi
504
+ assert log(-1/(1 - x)).as_leading_term(x, cdir=1) == I*pi
505
+ assert log(-1/(1 - x)).as_leading_term(x, cdir=-1) == I*pi
506
+
507
+
508
+ def test_log_nseries():
509
+ p = Symbol('p')
510
+ assert log(1/x)._eval_nseries(x, 4, logx=-p, cdir=1) == p
511
+ assert log(1/x)._eval_nseries(x, 4, logx=-p, cdir=-1) == p + 2*I*pi
512
+ assert log(x - 1)._eval_nseries(x, 4, None, I) == I*pi - x - x**2/2 - x**3/3 + O(x**4)
513
+ assert log(x - 1)._eval_nseries(x, 4, None, -I) == -I*pi - x - x**2/2 - x**3/3 + O(x**4)
514
+ assert log(I*x + I*x**3 - 1)._eval_nseries(x, 3, None, 1) == I*pi - I*x + x**2/2 + O(x**3)
515
+ assert log(I*x + I*x**3 - 1)._eval_nseries(x, 3, None, -1) == -I*pi - I*x + x**2/2 + O(x**3)
516
+ assert log(I*x**2 + I*x**3 - 1)._eval_nseries(x, 3, None, 1) == I*pi - I*x**2 + O(x**3)
517
+ assert log(I*x**2 + I*x**3 - 1)._eval_nseries(x, 3, None, -1) == I*pi - I*x**2 + O(x**3)
518
+ assert log(2*x + (3 - I)*x**2)._eval_nseries(x, 3, None, 1) == log(2) + log(x) + \
519
+ x*(S(3)/2 - I/2) + x**2*(-1 + 3*I/4) + O(x**3)
520
+ assert log(2*x + (3 - I)*x**2)._eval_nseries(x, 3, None, -1) == -2*I*pi + log(2) + \
521
+ log(x) - x*(-S(3)/2 + I/2) + x**2*(-1 + 3*I/4) + O(x**3)
522
+ assert log(-2*x + (3 - I)*x**2)._eval_nseries(x, 3, None, 1) == -I*pi + log(2) + log(x) + \
523
+ x*(-S(3)/2 + I/2) + x**2*(-1 + 3*I/4) + O(x**3)
524
+ assert log(-2*x + (3 - I)*x**2)._eval_nseries(x, 3, None, -1) == -I*pi + log(2) + log(x) - \
525
+ x*(S(3)/2 - I/2) + x**2*(-1 + 3*I/4) + O(x**3)
526
+ assert log(sqrt(-I*x**2 - 3)*sqrt(-I*x**2 - 1) - 2)._eval_nseries(x, 3, None, 1) == -I*pi + \
527
+ log(sqrt(3) + 2) + I*x**2*(-2 + 4*sqrt(3)/3) + O(x**3)
528
+ assert log(-1/(1 - x))._eval_nseries(x, 3, None, 1) == I*pi + x + x**2/2 + O(x**3)
529
+ assert log(-1/(1 - x))._eval_nseries(x, 3, None, -1) == I*pi + x + x**2/2 + O(x**3)
530
+
531
+
532
+ def test_log_series():
533
+ # Note Series at infinities other than oo/-oo were introduced as a part of
534
+ # pull request 23798. Refer https://github.com/sympy/sympy/pull/23798 for
535
+ # more information.
536
+ expr1 = log(1 + x)
537
+ expr2 = log(x + sqrt(x**2 + 1))
538
+
539
+ assert expr1.series(x, x0=I*oo, n=4) == 1/(3*x**3) - 1/(2*x**2) + 1/x + \
540
+ I*pi/2 - log(I/x) + O(x**(-4), (x, oo*I))
541
+ assert expr1.series(x, x0=-I*oo, n=4) == 1/(3*x**3) - 1/(2*x**2) + 1/x - \
542
+ I*pi/2 - log(-I/x) + O(x**(-4), (x, -oo*I))
543
+ assert expr2.series(x, x0=I*oo, n=4) == 1/(4*x**2) + I*pi/2 + log(2) - \
544
+ log(I/x) + O(x**(-4), (x, oo*I))
545
+ assert expr2.series(x, x0=-I*oo, n=4) == -1/(4*x**2) - I*pi/2 - log(2) + \
546
+ log(-I/x) + O(x**(-4), (x, -oo*I))
547
+
548
+
549
+ def test_log_expand():
550
+ w = Symbol("w", positive=True)
551
+ e = log(w**(log(5)/log(3)))
552
+ assert e.expand() == log(5)/log(3) * log(w)
553
+ x, y, z = symbols('x,y,z', positive=True)
554
+ assert log(x*(y + z)).expand(mul=False) == log(x) + log(y + z)
555
+ assert log(log(x**2)*log(y*z)).expand() in [log(2*log(x)*log(y) +
556
+ 2*log(x)*log(z)), log(log(x)*log(z) + log(y)*log(x)) + log(2),
557
+ log((log(y) + log(z))*log(x)) + log(2)]
558
+ assert log(x**log(x**2)).expand(deep=False) == log(x)*log(x**2)
559
+ assert log(x**log(x**2)).expand() == 2*log(x)**2
560
+ x, y = symbols('x,y')
561
+ assert log(x*y).expand(force=True) == log(x) + log(y)
562
+ assert log(x**y).expand(force=True) == y*log(x)
563
+ assert log(exp(x)).expand(force=True) == x
564
+
565
+ # there's generally no need to expand out logs since this requires
566
+ # factoring and if simplification is sought, it's cheaper to put
567
+ # logs together than it is to take them apart.
568
+ assert log(2*3**2).expand() != 2*log(3) + log(2)
569
+
570
+
571
+ @XFAIL
572
+ def test_log_expand_fail():
573
+ x, y, z = symbols('x,y,z', positive=True)
574
+ assert (log(x*(y + z))*(x + y)).expand(mul=True, log=True) == y*log(
575
+ x) + y*log(y + z) + z*log(x) + z*log(y + z)
576
+
577
+
578
+ def test_log_simplify():
579
+ x = Symbol("x", positive=True)
580
+ assert log(x**2).expand() == 2*log(x)
581
+ assert expand_log(log(x**(2 + log(2)))) == (2 + log(2))*log(x)
582
+
583
+ z = Symbol('z')
584
+ assert log(sqrt(z)).expand() == log(z)/2
585
+ assert expand_log(log(z**(log(2) - 1))) == (log(2) - 1)*log(z)
586
+ assert log(z**(-1)).expand() != -log(z)
587
+ assert log(z**(x/(x+1))).expand() == x*log(z)/(x + 1)
588
+
589
+
590
+ def test_log_AccumBounds():
591
+ assert log(AccumBounds(1, E)) == AccumBounds(0, 1)
592
+ assert log(AccumBounds(0, E)) == AccumBounds(-oo, 1)
593
+ assert log(AccumBounds(-1, E)) == S.NaN
594
+ assert log(AccumBounds(0, oo)) == AccumBounds(-oo, oo)
595
+ assert log(AccumBounds(-oo, 0)) == S.NaN
596
+ assert log(AccumBounds(-oo, oo)) == S.NaN
597
+
598
+
599
+ @_both_exp_pow
600
+ def test_lambertw():
601
+ k = Symbol('k')
602
+
603
+ assert LambertW(x, 0) == LambertW(x)
604
+ assert LambertW(x, 0, evaluate=False) != LambertW(x)
605
+ assert LambertW(0) == 0
606
+ assert LambertW(E) == 1
607
+ assert LambertW(-1/E) == -1
608
+ assert LambertW(-log(2)/2) == -log(2)
609
+ assert LambertW(oo) is oo
610
+ assert LambertW(0, 1) is -oo
611
+ assert LambertW(0, 42) is -oo
612
+ assert LambertW(-pi/2, -1) == -I*pi/2
613
+ assert LambertW(-1/E, -1) == -1
614
+ assert LambertW(-2*exp(-2), -1) == -2
615
+ assert LambertW(2*log(2)) == log(2)
616
+ assert LambertW(-pi/2) == I*pi/2
617
+ assert LambertW(exp(1 + E)) == E
618
+
619
+ assert LambertW(x**2).diff(x) == 2*LambertW(x**2)/x/(1 + LambertW(x**2))
620
+ assert LambertW(x, k).diff(x) == LambertW(x, k)/x/(1 + LambertW(x, k))
621
+
622
+ assert LambertW(sqrt(2)).evalf(30).epsilon_eq(
623
+ Float("0.701338383413663009202120278965", 30), 1e-29)
624
+ assert re(LambertW(2, -1)).evalf().epsilon_eq(Float("-0.834310366631110"))
625
+
626
+ assert LambertW(-1).is_real is False # issue 5215
627
+ assert LambertW(2, evaluate=False).is_real
628
+ p = Symbol('p', positive=True)
629
+ assert LambertW(p, evaluate=False).is_real
630
+ assert LambertW(p - 1, evaluate=False).is_real is None
631
+ assert LambertW(-p - 2/S.Exp1, evaluate=False).is_real is False
632
+ assert LambertW(S.Half, -1, evaluate=False).is_real is False
633
+ assert LambertW(Rational(-1, 10), -1, evaluate=False).is_real
634
+ assert LambertW(-10, -1, evaluate=False).is_real is False
635
+ assert LambertW(-2, 2, evaluate=False).is_real is False
636
+
637
+ assert LambertW(0, evaluate=False).is_algebraic
638
+ na = Symbol('na', nonzero=True, algebraic=True)
639
+ assert LambertW(na).is_algebraic is False
640
+ assert LambertW(p).is_zero is False
641
+ n = Symbol('n', negative=True)
642
+ assert LambertW(n).is_zero is False
643
+
644
+
645
+ def test_issue_5673():
646
+ e = LambertW(-1)
647
+ assert e.is_comparable is False
648
+ assert e.is_positive is not True
649
+ e2 = 1 - 1/(1 - exp(-1000))
650
+ assert e2.is_positive is not True
651
+ e3 = -2 + exp(exp(LambertW(log(2)))*LambertW(log(2)))
652
+ assert e3.is_nonzero is not True
653
+
654
+
655
+ def test_log_fdiff():
656
+ x = Symbol('x')
657
+ raises(ArgumentIndexError, lambda: log(x).fdiff(2))
658
+
659
+
660
+ def test_log_taylor_term():
661
+ x = symbols('x')
662
+ assert log(x).taylor_term(0, x) == x
663
+ assert log(x).taylor_term(1, x) == -x**2/2
664
+ assert log(x).taylor_term(4, x) == x**5/5
665
+ assert log(x).taylor_term(-1, x) is S.Zero
666
+
667
+
668
+ def test_exp_expand_NC():
669
+ A, B, C = symbols('A,B,C', commutative=False)
670
+
671
+ assert exp(A + B).expand() == exp(A + B)
672
+ assert exp(A + B + C).expand() == exp(A + B + C)
673
+ assert exp(x + y).expand() == exp(x)*exp(y)
674
+ assert exp(x + y + z).expand() == exp(x)*exp(y)*exp(z)
675
+
676
+
677
+ @_both_exp_pow
678
+ def test_as_numer_denom():
679
+ n = symbols('n', negative=True)
680
+ assert exp(x).as_numer_denom() == (exp(x), 1)
681
+ assert exp(-x).as_numer_denom() == (1, exp(x))
682
+ assert exp(-2*x).as_numer_denom() == (1, exp(2*x))
683
+ assert exp(-2).as_numer_denom() == (1, exp(2))
684
+ assert exp(n).as_numer_denom() == (1, exp(-n))
685
+ assert exp(-n).as_numer_denom() == (exp(-n), 1)
686
+ assert exp(-I*x).as_numer_denom() == (1, exp(I*x))
687
+ assert exp(-I*n).as_numer_denom() == (1, exp(I*n))
688
+ assert exp(-n).as_numer_denom() == (exp(-n), 1)
689
+
690
+
691
+ @_both_exp_pow
692
+ def test_polar():
693
+ x, y = symbols('x y', polar=True)
694
+
695
+ assert abs(exp_polar(I*4)) == 1
696
+ assert abs(exp_polar(0)) == 1
697
+ assert abs(exp_polar(2 + 3*I)) == exp(2)
698
+ assert exp_polar(I*10).n() == exp_polar(I*10)
699
+
700
+ assert log(exp_polar(z)) == z
701
+ assert log(x*y).expand() == log(x) + log(y)
702
+ assert log(x**z).expand() == z*log(x)
703
+
704
+ assert exp_polar(3).exp == 3
705
+
706
+ # Compare exp(1.0*pi*I).
707
+ assert (exp_polar(1.0*pi*I).n(n=5)).as_real_imag()[1] >= 0
708
+
709
+ assert exp_polar(0).is_rational is True # issue 8008
710
+
711
+
712
+ def test_exp_summation():
713
+ w = symbols("w")
714
+ m, n, i, j = symbols("m n i j")
715
+ expr = exp(Sum(w*i, (i, 0, n), (j, 0, m)))
716
+ assert expr.expand() == Product(exp(w*i), (i, 0, n), (j, 0, m))
717
+
718
+
719
+ def test_log_product():
720
+ from sympy.abc import n, m
721
+
722
+ i, j = symbols('i,j', positive=True, integer=True)
723
+ x, y = symbols('x,y', positive=True)
724
+ z = symbols('z', real=True)
725
+ w = symbols('w')
726
+
727
+ expr = log(Product(x**i, (i, 1, n)))
728
+ assert simplify(expr) == expr
729
+ assert expr.expand() == Sum(i*log(x), (i, 1, n))
730
+ expr = log(Product(x**i*y**j, (i, 1, n), (j, 1, m)))
731
+ assert simplify(expr) == expr
732
+ assert expr.expand() == Sum(i*log(x) + j*log(y), (i, 1, n), (j, 1, m))
733
+
734
+ expr = log(Product(-2, (n, 0, 4)))
735
+ assert simplify(expr) == expr
736
+ assert expr.expand() == expr
737
+ assert expr.expand(force=True) == Sum(log(-2), (n, 0, 4))
738
+
739
+ expr = log(Product(exp(z*i), (i, 0, n)))
740
+ assert expr.expand() == Sum(z*i, (i, 0, n))
741
+
742
+ expr = log(Product(exp(w*i), (i, 0, n)))
743
+ assert expr.expand() == expr
744
+ assert expr.expand(force=True) == Sum(w*i, (i, 0, n))
745
+
746
+ expr = log(Product(i**2*abs(j), (i, 1, n), (j, 1, m)))
747
+ assert expr.expand() == Sum(2*log(i) + log(j), (i, 1, n), (j, 1, m))
748
+
749
+
750
+ @XFAIL
751
+ def test_log_product_simplify_to_sum():
752
+ from sympy.abc import n, m
753
+ i, j = symbols('i,j', positive=True, integer=True)
754
+ x, y = symbols('x,y', positive=True)
755
+ assert simplify(log(Product(x**i, (i, 1, n)))) == Sum(i*log(x), (i, 1, n))
756
+ assert simplify(log(Product(x**i*y**j, (i, 1, n), (j, 1, m)))) == \
757
+ Sum(i*log(x) + j*log(y), (i, 1, n), (j, 1, m))
758
+
759
+
760
+ def test_issue_8866():
761
+ assert simplify(log(x, 10, evaluate=False)) == simplify(log(x, 10))
762
+ assert expand_log(log(x, 10, evaluate=False)) == expand_log(log(x, 10))
763
+
764
+ y = Symbol('y', positive=True)
765
+ l1 = log(exp(y), exp(10))
766
+ b1 = log(exp(y), exp(5))
767
+ l2 = log(exp(y), exp(10), evaluate=False)
768
+ b2 = log(exp(y), exp(5), evaluate=False)
769
+ assert simplify(log(l1, b1)) == simplify(log(l2, b2))
770
+ assert expand_log(log(l1, b1)) == expand_log(log(l2, b2))
771
+
772
+
773
+ def test_log_expand_factor():
774
+ assert (log(18)/log(3) - 2).expand(factor=True) == log(2)/log(3)
775
+ assert (log(12)/log(2)).expand(factor=True) == log(3)/log(2) + 2
776
+ assert (log(15)/log(3)).expand(factor=True) == 1 + log(5)/log(3)
777
+ assert (log(2)/(-log(12) + log(24))).expand(factor=True) == 1
778
+
779
+ assert expand_log(log(12), factor=True) == log(3) + 2*log(2)
780
+ assert expand_log(log(21)/log(7), factor=False) == log(3)/log(7) + 1
781
+ assert expand_log(log(45)/log(5) + log(20), factor=False) == \
782
+ 1 + 2*log(3)/log(5) + log(20)
783
+ assert expand_log(log(45)/log(5) + log(26), factor=True) == \
784
+ log(2) + log(13) + (log(5) + 2*log(3))/log(5)
785
+
786
+
787
+ def test_issue_9116():
788
+ n = Symbol('n', positive=True, integer=True)
789
+ assert log(n).is_nonnegative is True
790
+
791
+
792
+ def test_issue_18473():
793
+ assert exp(x*log(cos(1/x))).as_leading_term(x) == S.NaN
794
+ assert exp(x*log(tan(1/x))).as_leading_term(x) == S.NaN
795
+ assert log(cos(1/x)).as_leading_term(x) == S.NaN
796
+ assert log(tan(1/x)).as_leading_term(x) == S.NaN
797
+ assert log(cos(1/x) + 2).as_leading_term(x) == AccumBounds(0, log(3))
798
+ assert exp(x*log(cos(1/x) + 2)).as_leading_term(x) == 1
799
+ assert log(cos(1/x) - 2).as_leading_term(x) == S.NaN
800
+ assert exp(x*log(cos(1/x) - 2)).as_leading_term(x) == S.NaN
801
+ assert log(cos(1/x) + 1).as_leading_term(x) == AccumBounds(-oo, log(2))
802
+ assert exp(x*log(cos(1/x) + 1)).as_leading_term(x) == AccumBounds(0, 1)
803
+ assert log(sin(1/x)**2).as_leading_term(x) == AccumBounds(-oo, 0)
804
+ assert exp(x*log(sin(1/x)**2)).as_leading_term(x) == AccumBounds(0, 1)
805
+ assert log(tan(1/x)**2).as_leading_term(x) == AccumBounds(-oo, oo)
806
+ assert exp(2*x*(log(tan(1/x)**2))).as_leading_term(x) == AccumBounds(0, oo)
venv/lib/python3.10/site-packages/sympy/functions/elementary/tests/test_interface.py ADDED
@@ -0,0 +1,72 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ # This test file tests the SymPy function interface, that people use to create
2
+ # their own new functions. It should be as easy as possible.
3
+ from sympy.core.function import Function
4
+ from sympy.core.sympify import sympify
5
+ from sympy.functions.elementary.hyperbolic import tanh
6
+ from sympy.functions.elementary.trigonometric import (cos, sin)
7
+ from sympy.series.limits import limit
8
+ from sympy.abc import x
9
+
10
+
11
+ def test_function_series1():
12
+ """Create our new "sin" function."""
13
+
14
+ class my_function(Function):
15
+
16
+ def fdiff(self, argindex=1):
17
+ return cos(self.args[0])
18
+
19
+ @classmethod
20
+ def eval(cls, arg):
21
+ arg = sympify(arg)
22
+ if arg == 0:
23
+ return sympify(0)
24
+
25
+ #Test that the taylor series is correct
26
+ assert my_function(x).series(x, 0, 10) == sin(x).series(x, 0, 10)
27
+ assert limit(my_function(x)/x, x, 0) == 1
28
+
29
+
30
+ def test_function_series2():
31
+ """Create our new "cos" function."""
32
+
33
+ class my_function2(Function):
34
+
35
+ def fdiff(self, argindex=1):
36
+ return -sin(self.args[0])
37
+
38
+ @classmethod
39
+ def eval(cls, arg):
40
+ arg = sympify(arg)
41
+ if arg == 0:
42
+ return sympify(1)
43
+
44
+ #Test that the taylor series is correct
45
+ assert my_function2(x).series(x, 0, 10) == cos(x).series(x, 0, 10)
46
+
47
+
48
+ def test_function_series3():
49
+ """
50
+ Test our easy "tanh" function.
51
+
52
+ This test tests two things:
53
+ * that the Function interface works as expected and it's easy to use
54
+ * that the general algorithm for the series expansion works even when the
55
+ derivative is defined recursively in terms of the original function,
56
+ since tanh(x).diff(x) == 1-tanh(x)**2
57
+ """
58
+
59
+ class mytanh(Function):
60
+
61
+ def fdiff(self, argindex=1):
62
+ return 1 - mytanh(self.args[0])**2
63
+
64
+ @classmethod
65
+ def eval(cls, arg):
66
+ arg = sympify(arg)
67
+ if arg == 0:
68
+ return sympify(0)
69
+
70
+ e = tanh(x)
71
+ f = mytanh(x)
72
+ assert e.series(x, 0, 6) == f.series(x, 0, 6)
venv/lib/python3.10/site-packages/sympy/functions/elementary/tests/test_miscellaneous.py ADDED
@@ -0,0 +1,504 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ import itertools as it
2
+
3
+ from sympy.core.expr import unchanged
4
+ from sympy.core.function import Function
5
+ from sympy.core.numbers import I, oo, Rational
6
+ from sympy.core.power import Pow
7
+ from sympy.core.singleton import S
8
+ from sympy.core.symbol import Symbol
9
+ from sympy.external import import_module
10
+ from sympy.functions.elementary.exponential import log
11
+ from sympy.functions.elementary.integers import floor, ceiling
12
+ from sympy.functions.elementary.miscellaneous import (sqrt, cbrt, root, Min,
13
+ Max, real_root, Rem)
14
+ from sympy.functions.elementary.trigonometric import cos, sin
15
+ from sympy.functions.special.delta_functions import Heaviside
16
+
17
+ from sympy.utilities.lambdify import lambdify
18
+ from sympy.testing.pytest import raises, skip, ignore_warnings
19
+
20
+ def test_Min():
21
+ from sympy.abc import x, y, z
22
+ n = Symbol('n', negative=True)
23
+ n_ = Symbol('n_', negative=True)
24
+ nn = Symbol('nn', nonnegative=True)
25
+ nn_ = Symbol('nn_', nonnegative=True)
26
+ p = Symbol('p', positive=True)
27
+ p_ = Symbol('p_', positive=True)
28
+ np = Symbol('np', nonpositive=True)
29
+ np_ = Symbol('np_', nonpositive=True)
30
+ r = Symbol('r', real=True)
31
+
32
+ assert Min(5, 4) == 4
33
+ assert Min(-oo, -oo) is -oo
34
+ assert Min(-oo, n) is -oo
35
+ assert Min(n, -oo) is -oo
36
+ assert Min(-oo, np) is -oo
37
+ assert Min(np, -oo) is -oo
38
+ assert Min(-oo, 0) is -oo
39
+ assert Min(0, -oo) is -oo
40
+ assert Min(-oo, nn) is -oo
41
+ assert Min(nn, -oo) is -oo
42
+ assert Min(-oo, p) is -oo
43
+ assert Min(p, -oo) is -oo
44
+ assert Min(-oo, oo) is -oo
45
+ assert Min(oo, -oo) is -oo
46
+ assert Min(n, n) == n
47
+ assert unchanged(Min, n, np)
48
+ assert Min(np, n) == Min(n, np)
49
+ assert Min(n, 0) == n
50
+ assert Min(0, n) == n
51
+ assert Min(n, nn) == n
52
+ assert Min(nn, n) == n
53
+ assert Min(n, p) == n
54
+ assert Min(p, n) == n
55
+ assert Min(n, oo) == n
56
+ assert Min(oo, n) == n
57
+ assert Min(np, np) == np
58
+ assert Min(np, 0) == np
59
+ assert Min(0, np) == np
60
+ assert Min(np, nn) == np
61
+ assert Min(nn, np) == np
62
+ assert Min(np, p) == np
63
+ assert Min(p, np) == np
64
+ assert Min(np, oo) == np
65
+ assert Min(oo, np) == np
66
+ assert Min(0, 0) == 0
67
+ assert Min(0, nn) == 0
68
+ assert Min(nn, 0) == 0
69
+ assert Min(0, p) == 0
70
+ assert Min(p, 0) == 0
71
+ assert Min(0, oo) == 0
72
+ assert Min(oo, 0) == 0
73
+ assert Min(nn, nn) == nn
74
+ assert unchanged(Min, nn, p)
75
+ assert Min(p, nn) == Min(nn, p)
76
+ assert Min(nn, oo) == nn
77
+ assert Min(oo, nn) == nn
78
+ assert Min(p, p) == p
79
+ assert Min(p, oo) == p
80
+ assert Min(oo, p) == p
81
+ assert Min(oo, oo) is oo
82
+
83
+ assert Min(n, n_).func is Min
84
+ assert Min(nn, nn_).func is Min
85
+ assert Min(np, np_).func is Min
86
+ assert Min(p, p_).func is Min
87
+
88
+ # lists
89
+ assert Min() is S.Infinity
90
+ assert Min(x) == x
91
+ assert Min(x, y) == Min(y, x)
92
+ assert Min(x, y, z) == Min(z, y, x)
93
+ assert Min(x, Min(y, z)) == Min(z, y, x)
94
+ assert Min(x, Max(y, -oo)) == Min(x, y)
95
+ assert Min(p, oo, n, p, p, p_) == n
96
+ assert Min(p_, n_, p) == n_
97
+ assert Min(n, oo, -7, p, p, 2) == Min(n, -7)
98
+ assert Min(2, x, p, n, oo, n_, p, 2, -2, -2) == Min(-2, x, n, n_)
99
+ assert Min(0, x, 1, y) == Min(0, x, y)
100
+ assert Min(1000, 100, -100, x, p, n) == Min(n, x, -100)
101
+ assert unchanged(Min, sin(x), cos(x))
102
+ assert Min(sin(x), cos(x)) == Min(cos(x), sin(x))
103
+ assert Min(cos(x), sin(x)).subs(x, 1) == cos(1)
104
+ assert Min(cos(x), sin(x)).subs(x, S.Half) == sin(S.Half)
105
+ raises(ValueError, lambda: Min(cos(x), sin(x)).subs(x, I))
106
+ raises(ValueError, lambda: Min(I))
107
+ raises(ValueError, lambda: Min(I, x))
108
+ raises(ValueError, lambda: Min(S.ComplexInfinity, x))
109
+
110
+ assert Min(1, x).diff(x) == Heaviside(1 - x)
111
+ assert Min(x, 1).diff(x) == Heaviside(1 - x)
112
+ assert Min(0, -x, 1 - 2*x).diff(x) == -Heaviside(x + Min(0, -2*x + 1)) \
113
+ - 2*Heaviside(2*x + Min(0, -x) - 1)
114
+
115
+ # issue 7619
116
+ f = Function('f')
117
+ assert Min(1, 2*Min(f(1), 2)) # doesn't fail
118
+
119
+ # issue 7233
120
+ e = Min(0, x)
121
+ assert e.n().args == (0, x)
122
+
123
+ # issue 8643
124
+ m = Min(n, p_, n_, r)
125
+ assert m.is_positive is False
126
+ assert m.is_nonnegative is False
127
+ assert m.is_negative is True
128
+
129
+ m = Min(p, p_)
130
+ assert m.is_positive is True
131
+ assert m.is_nonnegative is True
132
+ assert m.is_negative is False
133
+
134
+ m = Min(p, nn_, p_)
135
+ assert m.is_positive is None
136
+ assert m.is_nonnegative is True
137
+ assert m.is_negative is False
138
+
139
+ m = Min(nn, p, r)
140
+ assert m.is_positive is None
141
+ assert m.is_nonnegative is None
142
+ assert m.is_negative is None
143
+
144
+
145
+ def test_Max():
146
+ from sympy.abc import x, y, z
147
+ n = Symbol('n', negative=True)
148
+ n_ = Symbol('n_', negative=True)
149
+ nn = Symbol('nn', nonnegative=True)
150
+ p = Symbol('p', positive=True)
151
+ p_ = Symbol('p_', positive=True)
152
+ r = Symbol('r', real=True)
153
+
154
+ assert Max(5, 4) == 5
155
+
156
+ # lists
157
+
158
+ assert Max() is S.NegativeInfinity
159
+ assert Max(x) == x
160
+ assert Max(x, y) == Max(y, x)
161
+ assert Max(x, y, z) == Max(z, y, x)
162
+ assert Max(x, Max(y, z)) == Max(z, y, x)
163
+ assert Max(x, Min(y, oo)) == Max(x, y)
164
+ assert Max(n, -oo, n_, p, 2) == Max(p, 2)
165
+ assert Max(n, -oo, n_, p) == p
166
+ assert Max(2, x, p, n, -oo, S.NegativeInfinity, n_, p, 2) == Max(2, x, p)
167
+ assert Max(0, x, 1, y) == Max(1, x, y)
168
+ assert Max(r, r + 1, r - 1) == 1 + r
169
+ assert Max(1000, 100, -100, x, p, n) == Max(p, x, 1000)
170
+ assert Max(cos(x), sin(x)) == Max(sin(x), cos(x))
171
+ assert Max(cos(x), sin(x)).subs(x, 1) == sin(1)
172
+ assert Max(cos(x), sin(x)).subs(x, S.Half) == cos(S.Half)
173
+ raises(ValueError, lambda: Max(cos(x), sin(x)).subs(x, I))
174
+ raises(ValueError, lambda: Max(I))
175
+ raises(ValueError, lambda: Max(I, x))
176
+ raises(ValueError, lambda: Max(S.ComplexInfinity, 1))
177
+ assert Max(n, -oo, n_, p, 2) == Max(p, 2)
178
+ assert Max(n, -oo, n_, p, 1000) == Max(p, 1000)
179
+
180
+ assert Max(1, x).diff(x) == Heaviside(x - 1)
181
+ assert Max(x, 1).diff(x) == Heaviside(x - 1)
182
+ assert Max(x**2, 1 + x, 1).diff(x) == \
183
+ 2*x*Heaviside(x**2 - Max(1, x + 1)) \
184
+ + Heaviside(x - Max(1, x**2) + 1)
185
+
186
+ e = Max(0, x)
187
+ assert e.n().args == (0, x)
188
+
189
+ # issue 8643
190
+ m = Max(p, p_, n, r)
191
+ assert m.is_positive is True
192
+ assert m.is_nonnegative is True
193
+ assert m.is_negative is False
194
+
195
+ m = Max(n, n_)
196
+ assert m.is_positive is False
197
+ assert m.is_nonnegative is False
198
+ assert m.is_negative is True
199
+
200
+ m = Max(n, n_, r)
201
+ assert m.is_positive is None
202
+ assert m.is_nonnegative is None
203
+ assert m.is_negative is None
204
+
205
+ m = Max(n, nn, r)
206
+ assert m.is_positive is None
207
+ assert m.is_nonnegative is True
208
+ assert m.is_negative is False
209
+
210
+
211
+ def test_minmax_assumptions():
212
+ r = Symbol('r', real=True)
213
+ a = Symbol('a', real=True, algebraic=True)
214
+ t = Symbol('t', real=True, transcendental=True)
215
+ q = Symbol('q', rational=True)
216
+ p = Symbol('p', irrational=True)
217
+ n = Symbol('n', rational=True, integer=False)
218
+ i = Symbol('i', integer=True)
219
+ o = Symbol('o', odd=True)
220
+ e = Symbol('e', even=True)
221
+ k = Symbol('k', prime=True)
222
+ reals = [r, a, t, q, p, n, i, o, e, k]
223
+
224
+ for ext in (Max, Min):
225
+ for x, y in it.product(reals, repeat=2):
226
+
227
+ # Must be real
228
+ assert ext(x, y).is_real
229
+
230
+ # Algebraic?
231
+ if x.is_algebraic and y.is_algebraic:
232
+ assert ext(x, y).is_algebraic
233
+ elif x.is_transcendental and y.is_transcendental:
234
+ assert ext(x, y).is_transcendental
235
+ else:
236
+ assert ext(x, y).is_algebraic is None
237
+
238
+ # Rational?
239
+ if x.is_rational and y.is_rational:
240
+ assert ext(x, y).is_rational
241
+ elif x.is_irrational and y.is_irrational:
242
+ assert ext(x, y).is_irrational
243
+ else:
244
+ assert ext(x, y).is_rational is None
245
+
246
+ # Integer?
247
+ if x.is_integer and y.is_integer:
248
+ assert ext(x, y).is_integer
249
+ elif x.is_noninteger and y.is_noninteger:
250
+ assert ext(x, y).is_noninteger
251
+ else:
252
+ assert ext(x, y).is_integer is None
253
+
254
+ # Odd?
255
+ if x.is_odd and y.is_odd:
256
+ assert ext(x, y).is_odd
257
+ elif x.is_odd is False and y.is_odd is False:
258
+ assert ext(x, y).is_odd is False
259
+ else:
260
+ assert ext(x, y).is_odd is None
261
+
262
+ # Even?
263
+ if x.is_even and y.is_even:
264
+ assert ext(x, y).is_even
265
+ elif x.is_even is False and y.is_even is False:
266
+ assert ext(x, y).is_even is False
267
+ else:
268
+ assert ext(x, y).is_even is None
269
+
270
+ # Prime?
271
+ if x.is_prime and y.is_prime:
272
+ assert ext(x, y).is_prime
273
+ elif x.is_prime is False and y.is_prime is False:
274
+ assert ext(x, y).is_prime is False
275
+ else:
276
+ assert ext(x, y).is_prime is None
277
+
278
+
279
+ def test_issue_8413():
280
+ x = Symbol('x', real=True)
281
+ # we can't evaluate in general because non-reals are not
282
+ # comparable: Min(floor(3.2 + I), 3.2 + I) -> ValueError
283
+ assert Min(floor(x), x) == floor(x)
284
+ assert Min(ceiling(x), x) == x
285
+ assert Max(floor(x), x) == x
286
+ assert Max(ceiling(x), x) == ceiling(x)
287
+
288
+
289
+ def test_root():
290
+ from sympy.abc import x
291
+ n = Symbol('n', integer=True)
292
+ k = Symbol('k', integer=True)
293
+
294
+ assert root(2, 2) == sqrt(2)
295
+ assert root(2, 1) == 2
296
+ assert root(2, 3) == 2**Rational(1, 3)
297
+ assert root(2, 3) == cbrt(2)
298
+ assert root(2, -5) == 2**Rational(4, 5)/2
299
+
300
+ assert root(-2, 1) == -2
301
+
302
+ assert root(-2, 2) == sqrt(2)*I
303
+ assert root(-2, 1) == -2
304
+
305
+ assert root(x, 2) == sqrt(x)
306
+ assert root(x, 1) == x
307
+ assert root(x, 3) == x**Rational(1, 3)
308
+ assert root(x, 3) == cbrt(x)
309
+ assert root(x, -5) == x**Rational(-1, 5)
310
+
311
+ assert root(x, n) == x**(1/n)
312
+ assert root(x, -n) == x**(-1/n)
313
+
314
+ assert root(x, n, k) == (-1)**(2*k/n)*x**(1/n)
315
+
316
+
317
+ def test_real_root():
318
+ assert real_root(-8, 3) == -2
319
+ assert real_root(-16, 4) == root(-16, 4)
320
+ r = root(-7, 4)
321
+ assert real_root(r) == r
322
+ r1 = root(-1, 3)
323
+ r2 = r1**2
324
+ r3 = root(-1, 4)
325
+ assert real_root(r1 + r2 + r3) == -1 + r2 + r3
326
+ assert real_root(root(-2, 3)) == -root(2, 3)
327
+ assert real_root(-8., 3) == -2.0
328
+ x = Symbol('x')
329
+ n = Symbol('n')
330
+ g = real_root(x, n)
331
+ assert g.subs({"x": -8, "n": 3}) == -2
332
+ assert g.subs({"x": 8, "n": 3}) == 2
333
+ # give principle root if there is no real root -- if this is not desired
334
+ # then maybe a Root class is needed to raise an error instead
335
+ assert g.subs({"x": I, "n": 3}) == cbrt(I)
336
+ assert g.subs({"x": -8, "n": 2}) == sqrt(-8)
337
+ assert g.subs({"x": I, "n": 2}) == sqrt(I)
338
+
339
+
340
+ def test_issue_11463():
341
+ numpy = import_module('numpy')
342
+ if not numpy:
343
+ skip("numpy not installed.")
344
+ x = Symbol('x')
345
+ f = lambdify(x, real_root((log(x/(x-2))), 3), 'numpy')
346
+ # numpy.select evaluates all options before considering conditions,
347
+ # so it raises a warning about root of negative number which does
348
+ # not affect the outcome. This warning is suppressed here
349
+ with ignore_warnings(RuntimeWarning):
350
+ assert f(numpy.array(-1)) < -1
351
+
352
+
353
+ def test_rewrite_MaxMin_as_Heaviside():
354
+ from sympy.abc import x
355
+ assert Max(0, x).rewrite(Heaviside) == x*Heaviside(x)
356
+ assert Max(3, x).rewrite(Heaviside) == x*Heaviside(x - 3) + \
357
+ 3*Heaviside(-x + 3)
358
+ assert Max(0, x+2, 2*x).rewrite(Heaviside) == \
359
+ 2*x*Heaviside(2*x)*Heaviside(x - 2) + \
360
+ (x + 2)*Heaviside(-x + 2)*Heaviside(x + 2)
361
+
362
+ assert Min(0, x).rewrite(Heaviside) == x*Heaviside(-x)
363
+ assert Min(3, x).rewrite(Heaviside) == x*Heaviside(-x + 3) + \
364
+ 3*Heaviside(x - 3)
365
+ assert Min(x, -x, -2).rewrite(Heaviside) == \
366
+ x*Heaviside(-2*x)*Heaviside(-x - 2) - \
367
+ x*Heaviside(2*x)*Heaviside(x - 2) \
368
+ - 2*Heaviside(-x + 2)*Heaviside(x + 2)
369
+
370
+
371
+ def test_rewrite_MaxMin_as_Piecewise():
372
+ from sympy.core.symbol import symbols
373
+ from sympy.functions.elementary.piecewise import Piecewise
374
+ x, y, z, a, b = symbols('x y z a b', real=True)
375
+ vx, vy, va = symbols('vx vy va')
376
+ assert Max(a, b).rewrite(Piecewise) == Piecewise((a, a >= b), (b, True))
377
+ assert Max(x, y, z).rewrite(Piecewise) == Piecewise((x, (x >= y) & (x >= z)), (y, y >= z), (z, True))
378
+ assert Max(x, y, a, b).rewrite(Piecewise) == Piecewise((a, (a >= b) & (a >= x) & (a >= y)),
379
+ (b, (b >= x) & (b >= y)), (x, x >= y), (y, True))
380
+ assert Min(a, b).rewrite(Piecewise) == Piecewise((a, a <= b), (b, True))
381
+ assert Min(x, y, z).rewrite(Piecewise) == Piecewise((x, (x <= y) & (x <= z)), (y, y <= z), (z, True))
382
+ assert Min(x, y, a, b).rewrite(Piecewise) == Piecewise((a, (a <= b) & (a <= x) & (a <= y)),
383
+ (b, (b <= x) & (b <= y)), (x, x <= y), (y, True))
384
+
385
+ # Piecewise rewriting of Min/Max does also takes place for not explicitly real arguments
386
+ assert Max(vx, vy).rewrite(Piecewise) == Piecewise((vx, vx >= vy), (vy, True))
387
+ assert Min(va, vx, vy).rewrite(Piecewise) == Piecewise((va, (va <= vx) & (va <= vy)), (vx, vx <= vy), (vy, True))
388
+
389
+
390
+ def test_issue_11099():
391
+ from sympy.abc import x, y
392
+ # some fixed value tests
393
+ fixed_test_data = {x: -2, y: 3}
394
+ assert Min(x, y).evalf(subs=fixed_test_data) == \
395
+ Min(x, y).subs(fixed_test_data).evalf()
396
+ assert Max(x, y).evalf(subs=fixed_test_data) == \
397
+ Max(x, y).subs(fixed_test_data).evalf()
398
+ # randomly generate some test data
399
+ from sympy.core.random import randint
400
+ for i in range(20):
401
+ random_test_data = {x: randint(-100, 100), y: randint(-100, 100)}
402
+ assert Min(x, y).evalf(subs=random_test_data) == \
403
+ Min(x, y).subs(random_test_data).evalf()
404
+ assert Max(x, y).evalf(subs=random_test_data) == \
405
+ Max(x, y).subs(random_test_data).evalf()
406
+
407
+
408
+ def test_issue_12638():
409
+ from sympy.abc import a, b, c
410
+ assert Min(a, b, c, Max(a, b)) == Min(a, b, c)
411
+ assert Min(a, b, Max(a, b, c)) == Min(a, b)
412
+ assert Min(a, b, Max(a, c)) == Min(a, b)
413
+
414
+ def test_issue_21399():
415
+ from sympy.abc import a, b, c
416
+ assert Max(Min(a, b), Min(a, b, c)) == Min(a, b)
417
+
418
+
419
+ def test_instantiation_evaluation():
420
+ from sympy.abc import v, w, x, y, z
421
+ assert Min(1, Max(2, x)) == 1
422
+ assert Max(3, Min(2, x)) == 3
423
+ assert Min(Max(x, y), Max(x, z)) == Max(x, Min(y, z))
424
+ assert set(Min(Max(w, x), Max(y, z)).args) == {
425
+ Max(w, x), Max(y, z)}
426
+ assert Min(Max(x, y), Max(x, z), w) == Min(
427
+ w, Max(x, Min(y, z)))
428
+ A, B = Min, Max
429
+ for i in range(2):
430
+ assert A(x, B(x, y)) == x
431
+ assert A(x, B(y, A(x, w, z))) == A(x, B(y, A(w, z)))
432
+ A, B = B, A
433
+ assert Min(w, Max(x, y), Max(v, x, z)) == Min(
434
+ w, Max(x, Min(y, Max(v, z))))
435
+
436
+ def test_rewrite_as_Abs():
437
+ from itertools import permutations
438
+ from sympy.functions.elementary.complexes import Abs
439
+ from sympy.abc import x, y, z, w
440
+ def test(e):
441
+ free = e.free_symbols
442
+ a = e.rewrite(Abs)
443
+ assert not a.has(Min, Max)
444
+ for i in permutations(range(len(free))):
445
+ reps = dict(zip(free, i))
446
+ assert a.xreplace(reps) == e.xreplace(reps)
447
+ test(Min(x, y))
448
+ test(Max(x, y))
449
+ test(Min(x, y, z))
450
+ test(Min(Max(w, x), Max(y, z)))
451
+
452
+ def test_issue_14000():
453
+ assert isinstance(sqrt(4, evaluate=False), Pow) == True
454
+ assert isinstance(cbrt(3.5, evaluate=False), Pow) == True
455
+ assert isinstance(root(16, 4, evaluate=False), Pow) == True
456
+
457
+ assert sqrt(4, evaluate=False) == Pow(4, S.Half, evaluate=False)
458
+ assert cbrt(3.5, evaluate=False) == Pow(3.5, Rational(1, 3), evaluate=False)
459
+ assert root(4, 2, evaluate=False) == Pow(4, S.Half, evaluate=False)
460
+
461
+ assert root(16, 4, 2, evaluate=False).has(Pow) == True
462
+ assert real_root(-8, 3, evaluate=False).has(Pow) == True
463
+
464
+ def test_issue_6899():
465
+ from sympy.core.function import Lambda
466
+ x = Symbol('x')
467
+ eqn = Lambda(x, x)
468
+ assert eqn.func(*eqn.args) == eqn
469
+
470
+ def test_Rem():
471
+ from sympy.abc import x, y
472
+ assert Rem(5, 3) == 2
473
+ assert Rem(-5, 3) == -2
474
+ assert Rem(5, -3) == 2
475
+ assert Rem(-5, -3) == -2
476
+ assert Rem(x**3, y) == Rem(x**3, y)
477
+ assert Rem(Rem(-5, 3) + 3, 3) == 1
478
+
479
+
480
+ def test_minmax_no_evaluate():
481
+ from sympy import evaluate
482
+ p = Symbol('p', positive=True)
483
+
484
+ assert Max(1, 3) == 3
485
+ assert Max(1, 3).args == ()
486
+ assert Max(0, p) == p
487
+ assert Max(0, p).args == ()
488
+ assert Min(0, p) == 0
489
+ assert Min(0, p).args == ()
490
+
491
+ assert Max(1, 3, evaluate=False) != 3
492
+ assert Max(1, 3, evaluate=False).args == (1, 3)
493
+ assert Max(0, p, evaluate=False) != p
494
+ assert Max(0, p, evaluate=False).args == (0, p)
495
+ assert Min(0, p, evaluate=False) != 0
496
+ assert Min(0, p, evaluate=False).args == (0, p)
497
+
498
+ with evaluate(False):
499
+ assert Max(1, 3) != 3
500
+ assert Max(1, 3).args == (1, 3)
501
+ assert Max(0, p) != p
502
+ assert Max(0, p).args == (0, p)
503
+ assert Min(0, p) != 0
504
+ assert Min(0, p).args == (0, p)
venv/lib/python3.10/site-packages/sympy/functions/elementary/tests/test_piecewise.py ADDED
@@ -0,0 +1,1606 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ from sympy.concrete.summations import Sum
2
+ from sympy.core.add import Add
3
+ from sympy.core.basic import Basic
4
+ from sympy.core.containers import Tuple
5
+ from sympy.core.expr import unchanged
6
+ from sympy.core.function import (Function, diff, expand)
7
+ from sympy.core.mul import Mul
8
+ from sympy.core.mod import Mod
9
+ from sympy.core.numbers import (Float, I, Rational, oo, pi, zoo)
10
+ from sympy.core.relational import (Eq, Ge, Gt, Ne)
11
+ from sympy.core.singleton import S
12
+ from sympy.core.symbol import (Symbol, symbols)
13
+ from sympy.functions.combinatorial.factorials import factorial
14
+ from sympy.functions.elementary.complexes import (Abs, adjoint, arg, conjugate, im, re, transpose)
15
+ from sympy.functions.elementary.exponential import (exp, log)
16
+ from sympy.functions.elementary.miscellaneous import (Max, Min, sqrt)
17
+ from sympy.functions.elementary.piecewise import (Piecewise,
18
+ piecewise_fold, piecewise_exclusive, Undefined, ExprCondPair)
19
+ from sympy.functions.elementary.trigonometric import (cos, sin)
20
+ from sympy.functions.special.delta_functions import (DiracDelta, Heaviside)
21
+ from sympy.functions.special.tensor_functions import KroneckerDelta
22
+ from sympy.integrals.integrals import (Integral, integrate)
23
+ from sympy.logic.boolalg import (And, ITE, Not, Or)
24
+ from sympy.matrices.expressions.matexpr import MatrixSymbol
25
+ from sympy.printing import srepr
26
+ from sympy.sets.contains import Contains
27
+ from sympy.sets.sets import Interval
28
+ from sympy.solvers.solvers import solve
29
+ from sympy.testing.pytest import raises, slow
30
+ from sympy.utilities.lambdify import lambdify
31
+
32
+ a, b, c, d, x, y = symbols('a:d, x, y')
33
+ z = symbols('z', nonzero=True)
34
+
35
+
36
+ def test_piecewise1():
37
+
38
+ # Test canonicalization
39
+ assert unchanged(Piecewise, ExprCondPair(x, x < 1), ExprCondPair(0, True))
40
+ assert Piecewise((x, x < 1), (0, True)) == Piecewise(ExprCondPair(x, x < 1),
41
+ ExprCondPair(0, True))
42
+ assert Piecewise((x, x < 1), (0, True), (1, True)) == \
43
+ Piecewise((x, x < 1), (0, True))
44
+ assert Piecewise((x, x < 1), (0, False), (-1, 1 > 2)) == \
45
+ Piecewise((x, x < 1))
46
+ assert Piecewise((x, x < 1), (0, x < 1), (0, True)) == \
47
+ Piecewise((x, x < 1), (0, True))
48
+ assert Piecewise((x, x < 1), (0, x < 2), (0, True)) == \
49
+ Piecewise((x, x < 1), (0, True))
50
+ assert Piecewise((x, x < 1), (x, x < 2), (0, True)) == \
51
+ Piecewise((x, Or(x < 1, x < 2)), (0, True))
52
+ assert Piecewise((x, x < 1), (x, x < 2), (x, True)) == x
53
+ assert Piecewise((x, True)) == x
54
+ # Explicitly constructed empty Piecewise not accepted
55
+ raises(TypeError, lambda: Piecewise())
56
+ # False condition is never retained
57
+ assert Piecewise((2*x, x < 0), (x, False)) == \
58
+ Piecewise((2*x, x < 0), (x, False), evaluate=False) == \
59
+ Piecewise((2*x, x < 0))
60
+ assert Piecewise((x, False)) == Undefined
61
+ raises(TypeError, lambda: Piecewise(x))
62
+ assert Piecewise((x, 1)) == x # 1 and 0 are accepted as True/False
63
+ raises(TypeError, lambda: Piecewise((x, 2)))
64
+ raises(TypeError, lambda: Piecewise((x, x**2)))
65
+ raises(TypeError, lambda: Piecewise(([1], True)))
66
+ assert Piecewise(((1, 2), True)) == Tuple(1, 2)
67
+ cond = (Piecewise((1, x < 0), (2, True)) < y)
68
+ assert Piecewise((1, cond)
69
+ ) == Piecewise((1, ITE(x < 0, y > 1, y > 2)))
70
+
71
+ assert Piecewise((1, x > 0), (2, And(x <= 0, x > -1))
72
+ ) == Piecewise((1, x > 0), (2, x > -1))
73
+ assert Piecewise((1, x <= 0), (2, (x < 0) & (x > -1))
74
+ ) == Piecewise((1, x <= 0))
75
+
76
+ # test for supporting Contains in Piecewise
77
+ pwise = Piecewise(
78
+ (1, And(x <= 6, x > 1, Contains(x, S.Integers))),
79
+ (0, True))
80
+ assert pwise.subs(x, pi) == 0
81
+ assert pwise.subs(x, 2) == 1
82
+ assert pwise.subs(x, 7) == 0
83
+
84
+ # Test subs
85
+ p = Piecewise((-1, x < -1), (x**2, x < 0), (log(x), x >= 0))
86
+ p_x2 = Piecewise((-1, x**2 < -1), (x**4, x**2 < 0), (log(x**2), x**2 >= 0))
87
+ assert p.subs(x, x**2) == p_x2
88
+ assert p.subs(x, -5) == -1
89
+ assert p.subs(x, -1) == 1
90
+ assert p.subs(x, 1) == log(1)
91
+
92
+ # More subs tests
93
+ p2 = Piecewise((1, x < pi), (-1, x < 2*pi), (0, x > 2*pi))
94
+ p3 = Piecewise((1, Eq(x, 0)), (1/x, True))
95
+ p4 = Piecewise((1, Eq(x, 0)), (2, 1/x>2))
96
+ assert p2.subs(x, 2) == 1
97
+ assert p2.subs(x, 4) == -1
98
+ assert p2.subs(x, 10) == 0
99
+ assert p3.subs(x, 0.0) == 1
100
+ assert p4.subs(x, 0.0) == 1
101
+
102
+
103
+ f, g, h = symbols('f,g,h', cls=Function)
104
+ pf = Piecewise((f(x), x < -1), (f(x) + h(x) + 2, x <= 1))
105
+ pg = Piecewise((g(x), x < -1), (g(x) + h(x) + 2, x <= 1))
106
+ assert pg.subs(g, f) == pf
107
+
108
+ assert Piecewise((1, Eq(x, 0)), (0, True)).subs(x, 0) == 1
109
+ assert Piecewise((1, Eq(x, 0)), (0, True)).subs(x, 1) == 0
110
+ assert Piecewise((1, Eq(x, y)), (0, True)).subs(x, y) == 1
111
+ assert Piecewise((1, Eq(x, z)), (0, True)).subs(x, z) == 1
112
+ assert Piecewise((1, Eq(exp(x), cos(z))), (0, True)).subs(x, z) == \
113
+ Piecewise((1, Eq(exp(z), cos(z))), (0, True))
114
+
115
+ p5 = Piecewise( (0, Eq(cos(x) + y, 0)), (1, True))
116
+ assert p5.subs(y, 0) == Piecewise( (0, Eq(cos(x), 0)), (1, True))
117
+
118
+ assert Piecewise((-1, y < 1), (0, x < 0), (1, Eq(x, 0)), (2, True)
119
+ ).subs(x, 1) == Piecewise((-1, y < 1), (2, True))
120
+ assert Piecewise((1, Eq(x**2, -1)), (2, x < 0)).subs(x, I) == 1
121
+
122
+ p6 = Piecewise((x, x > 0))
123
+ n = symbols('n', negative=True)
124
+ assert p6.subs(x, n) == Undefined
125
+
126
+ # Test evalf
127
+ assert p.evalf() == Piecewise((-1.0, x < -1), (x**2, x < 0), (log(x), True))
128
+ assert p.evalf(subs={x: -2}) == -1.0
129
+ assert p.evalf(subs={x: -1}) == 1.0
130
+ assert p.evalf(subs={x: 1}) == log(1)
131
+ assert p6.evalf(subs={x: -5}) == Undefined
132
+
133
+ # Test doit
134
+ f_int = Piecewise((Integral(x, (x, 0, 1)), x < 1))
135
+ assert f_int.doit() == Piecewise( (S.Half, x < 1) )
136
+
137
+ # Test differentiation
138
+ f = x
139
+ fp = x*p
140
+ dp = Piecewise((0, x < -1), (2*x, x < 0), (1/x, x >= 0))
141
+ fp_dx = x*dp + p
142
+ assert diff(p, x) == dp
143
+ assert diff(f*p, x) == fp_dx
144
+
145
+ # Test simple arithmetic
146
+ assert x*p == fp
147
+ assert x*p + p == p + x*p
148
+ assert p + f == f + p
149
+ assert p + dp == dp + p
150
+ assert p - dp == -(dp - p)
151
+
152
+ # Test power
153
+ dp2 = Piecewise((0, x < -1), (4*x**2, x < 0), (1/x**2, x >= 0))
154
+ assert dp**2 == dp2
155
+
156
+ # Test _eval_interval
157
+ f1 = x*y + 2
158
+ f2 = x*y**2 + 3
159
+ peval = Piecewise((f1, x < 0), (f2, x > 0))
160
+ peval_interval = f1.subs(
161
+ x, 0) - f1.subs(x, -1) + f2.subs(x, 1) - f2.subs(x, 0)
162
+ assert peval._eval_interval(x, 0, 0) == 0
163
+ assert peval._eval_interval(x, -1, 1) == peval_interval
164
+ peval2 = Piecewise((f1, x < 0), (f2, True))
165
+ assert peval2._eval_interval(x, 0, 0) == 0
166
+ assert peval2._eval_interval(x, 1, -1) == -peval_interval
167
+ assert peval2._eval_interval(x, -1, -2) == f1.subs(x, -2) - f1.subs(x, -1)
168
+ assert peval2._eval_interval(x, -1, 1) == peval_interval
169
+ assert peval2._eval_interval(x, None, 0) == peval2.subs(x, 0)
170
+ assert peval2._eval_interval(x, -1, None) == -peval2.subs(x, -1)
171
+
172
+ # Test integration
173
+ assert p.integrate() == Piecewise(
174
+ (-x, x < -1),
175
+ (x**3/3 + Rational(4, 3), x < 0),
176
+ (x*log(x) - x + Rational(4, 3), True))
177
+ p = Piecewise((x, x < 1), (x**2, -1 <= x), (x, 3 < x))
178
+ assert integrate(p, (x, -2, 2)) == Rational(5, 6)
179
+ assert integrate(p, (x, 2, -2)) == Rational(-5, 6)
180
+ p = Piecewise((0, x < 0), (1, x < 1), (0, x < 2), (1, x < 3), (0, True))
181
+ assert integrate(p, (x, -oo, oo)) == 2
182
+ p = Piecewise((x, x < -10), (x**2, x <= -1), (x, 1 < x))
183
+ assert integrate(p, (x, -2, 2)) == Undefined
184
+
185
+ # Test commutativity
186
+ assert isinstance(p, Piecewise) and p.is_commutative is True
187
+
188
+
189
+ def test_piecewise_free_symbols():
190
+ f = Piecewise((x, a < 0), (y, True))
191
+ assert f.free_symbols == {x, y, a}
192
+
193
+
194
+ def test_piecewise_integrate1():
195
+ x, y = symbols('x y', real=True)
196
+
197
+ f = Piecewise(((x - 2)**2, x >= 0), (1, True))
198
+ assert integrate(f, (x, -2, 2)) == Rational(14, 3)
199
+
200
+ g = Piecewise(((x - 5)**5, x >= 4), (f, True))
201
+ assert integrate(g, (x, -2, 2)) == Rational(14, 3)
202
+ assert integrate(g, (x, -2, 5)) == Rational(43, 6)
203
+
204
+ assert g == Piecewise(((x - 5)**5, x >= 4), (f, x < 4))
205
+
206
+ g = Piecewise(((x - 5)**5, 2 <= x), (f, x < 2))
207
+ assert integrate(g, (x, -2, 2)) == Rational(14, 3)
208
+ assert integrate(g, (x, -2, 5)) == Rational(-701, 6)
209
+
210
+ assert g == Piecewise(((x - 5)**5, 2 <= x), (f, True))
211
+
212
+ g = Piecewise(((x - 5)**5, 2 <= x), (2*f, True))
213
+ assert integrate(g, (x, -2, 2)) == Rational(28, 3)
214
+ assert integrate(g, (x, -2, 5)) == Rational(-673, 6)
215
+
216
+
217
+ def test_piecewise_integrate1b():
218
+ g = Piecewise((1, x > 0), (0, Eq(x, 0)), (-1, x < 0))
219
+ assert integrate(g, (x, -1, 1)) == 0
220
+
221
+ g = Piecewise((1, x - y < 0), (0, True))
222
+ assert integrate(g, (y, -oo, 0)) == -Min(0, x)
223
+ assert g.subs(x, -3).integrate((y, -oo, 0)) == 3
224
+ assert integrate(g, (y, 0, -oo)) == Min(0, x)
225
+ assert integrate(g, (y, 0, oo)) == -Max(0, x) + oo
226
+ assert integrate(g, (y, -oo, 42)) == -Min(42, x) + 42
227
+ assert integrate(g, (y, -oo, oo)) == -x + oo
228
+
229
+ g = Piecewise((0, x < 0), (x, x <= 1), (1, True))
230
+ gy1 = g.integrate((x, y, 1))
231
+ g1y = g.integrate((x, 1, y))
232
+ for yy in (-1, S.Half, 2):
233
+ assert g.integrate((x, yy, 1)) == gy1.subs(y, yy)
234
+ assert g.integrate((x, 1, yy)) == g1y.subs(y, yy)
235
+ assert gy1 == Piecewise(
236
+ (-Min(1, Max(0, y))**2/2 + S.Half, y < 1),
237
+ (-y + 1, True))
238
+ assert g1y == Piecewise(
239
+ (Min(1, Max(0, y))**2/2 - S.Half, y < 1),
240
+ (y - 1, True))
241
+
242
+
243
+ @slow
244
+ def test_piecewise_integrate1ca():
245
+ y = symbols('y', real=True)
246
+ g = Piecewise(
247
+ (1 - x, Interval(0, 1).contains(x)),
248
+ (1 + x, Interval(-1, 0).contains(x)),
249
+ (0, True)
250
+ )
251
+ gy1 = g.integrate((x, y, 1))
252
+ g1y = g.integrate((x, 1, y))
253
+
254
+ assert g.integrate((x, -2, 1)) == gy1.subs(y, -2)
255
+ assert g.integrate((x, 1, -2)) == g1y.subs(y, -2)
256
+ assert g.integrate((x, 0, 1)) == gy1.subs(y, 0)
257
+ assert g.integrate((x, 1, 0)) == g1y.subs(y, 0)
258
+ assert g.integrate((x, 2, 1)) == gy1.subs(y, 2)
259
+ assert g.integrate((x, 1, 2)) == g1y.subs(y, 2)
260
+ assert piecewise_fold(gy1.rewrite(Piecewise)
261
+ ).simplify() == Piecewise(
262
+ (1, y <= -1),
263
+ (-y**2/2 - y + S.Half, y <= 0),
264
+ (y**2/2 - y + S.Half, y < 1),
265
+ (0, True))
266
+ assert piecewise_fold(g1y.rewrite(Piecewise)
267
+ ).simplify() == Piecewise(
268
+ (-1, y <= -1),
269
+ (y**2/2 + y - S.Half, y <= 0),
270
+ (-y**2/2 + y - S.Half, y < 1),
271
+ (0, True))
272
+ assert gy1 == Piecewise(
273
+ (
274
+ -Min(1, Max(-1, y))**2/2 - Min(1, Max(-1, y)) +
275
+ Min(1, Max(0, y))**2 + S.Half, y < 1),
276
+ (0, True)
277
+ )
278
+ assert g1y == Piecewise(
279
+ (
280
+ Min(1, Max(-1, y))**2/2 + Min(1, Max(-1, y)) -
281
+ Min(1, Max(0, y))**2 - S.Half, y < 1),
282
+ (0, True))
283
+
284
+
285
+ @slow
286
+ def test_piecewise_integrate1cb():
287
+ y = symbols('y', real=True)
288
+ g = Piecewise(
289
+ (0, Or(x <= -1, x >= 1)),
290
+ (1 - x, x > 0),
291
+ (1 + x, True)
292
+ )
293
+ gy1 = g.integrate((x, y, 1))
294
+ g1y = g.integrate((x, 1, y))
295
+
296
+ assert g.integrate((x, -2, 1)) == gy1.subs(y, -2)
297
+ assert g.integrate((x, 1, -2)) == g1y.subs(y, -2)
298
+ assert g.integrate((x, 0, 1)) == gy1.subs(y, 0)
299
+ assert g.integrate((x, 1, 0)) == g1y.subs(y, 0)
300
+ assert g.integrate((x, 2, 1)) == gy1.subs(y, 2)
301
+ assert g.integrate((x, 1, 2)) == g1y.subs(y, 2)
302
+
303
+ assert piecewise_fold(gy1.rewrite(Piecewise)
304
+ ).simplify() == Piecewise(
305
+ (1, y <= -1),
306
+ (-y**2/2 - y + S.Half, y <= 0),
307
+ (y**2/2 - y + S.Half, y < 1),
308
+ (0, True))
309
+ assert piecewise_fold(g1y.rewrite(Piecewise)
310
+ ).simplify() == Piecewise(
311
+ (-1, y <= -1),
312
+ (y**2/2 + y - S.Half, y <= 0),
313
+ (-y**2/2 + y - S.Half, y < 1),
314
+ (0, True))
315
+
316
+ # g1y and gy1 should simplify if the condition that y < 1
317
+ # is applied, e.g. Min(1, Max(-1, y)) --> Max(-1, y)
318
+ assert gy1 == Piecewise(
319
+ (
320
+ -Min(1, Max(-1, y))**2/2 - Min(1, Max(-1, y)) +
321
+ Min(1, Max(0, y))**2 + S.Half, y < 1),
322
+ (0, True)
323
+ )
324
+ assert g1y == Piecewise(
325
+ (
326
+ Min(1, Max(-1, y))**2/2 + Min(1, Max(-1, y)) -
327
+ Min(1, Max(0, y))**2 - S.Half, y < 1),
328
+ (0, True))
329
+
330
+
331
+ def test_piecewise_integrate2():
332
+ from itertools import permutations
333
+ lim = Tuple(x, c, d)
334
+ p = Piecewise((1, x < a), (2, x > b), (3, True))
335
+ q = p.integrate(lim)
336
+ assert q == Piecewise(
337
+ (-c + 2*d - 2*Min(d, Max(a, c)) + Min(d, Max(a, b, c)), c < d),
338
+ (-2*c + d + 2*Min(c, Max(a, d)) - Min(c, Max(a, b, d)), True))
339
+ for v in permutations((1, 2, 3, 4)):
340
+ r = dict(zip((a, b, c, d), v))
341
+ assert p.subs(r).integrate(lim.subs(r)) == q.subs(r)
342
+
343
+
344
+ def test_meijer_bypass():
345
+ # totally bypass meijerg machinery when dealing
346
+ # with Piecewise in integrate
347
+ assert Piecewise((1, x < 4), (0, True)).integrate((x, oo, 1)) == -3
348
+
349
+
350
+ def test_piecewise_integrate3_inequality_conditions():
351
+ from sympy.utilities.iterables import cartes
352
+ lim = (x, 0, 5)
353
+ # set below includes two pts below range, 2 pts in range,
354
+ # 2 pts above range, and the boundaries
355
+ N = (-2, -1, 0, 1, 2, 5, 6, 7)
356
+
357
+ p = Piecewise((1, x > a), (2, x > b), (0, True))
358
+ ans = p.integrate(lim)
359
+ for i, j in cartes(N, repeat=2):
360
+ reps = dict(zip((a, b), (i, j)))
361
+ assert ans.subs(reps) == p.subs(reps).integrate(lim)
362
+ assert ans.subs(a, 4).subs(b, 1) == 0 + 2*3 + 1
363
+
364
+ p = Piecewise((1, x > a), (2, x < b), (0, True))
365
+ ans = p.integrate(lim)
366
+ for i, j in cartes(N, repeat=2):
367
+ reps = dict(zip((a, b), (i, j)))
368
+ assert ans.subs(reps) == p.subs(reps).integrate(lim)
369
+
370
+ # delete old tests that involved c1 and c2 since those
371
+ # reduce to the above except that a value of 0 was used
372
+ # for two expressions whereas the above uses 3 different
373
+ # values
374
+
375
+
376
+ @slow
377
+ def test_piecewise_integrate4_symbolic_conditions():
378
+ a = Symbol('a', real=True)
379
+ b = Symbol('b', real=True)
380
+ x = Symbol('x', real=True)
381
+ y = Symbol('y', real=True)
382
+ p0 = Piecewise((0, Or(x < a, x > b)), (1, True))
383
+ p1 = Piecewise((0, x < a), (0, x > b), (1, True))
384
+ p2 = Piecewise((0, x > b), (0, x < a), (1, True))
385
+ p3 = Piecewise((0, x < a), (1, x < b), (0, True))
386
+ p4 = Piecewise((0, x > b), (1, x > a), (0, True))
387
+ p5 = Piecewise((1, And(a < x, x < b)), (0, True))
388
+
389
+ # check values of a=1, b=3 (and reversed) with values
390
+ # of y of 0, 1, 2, 3, 4
391
+ lim = Tuple(x, -oo, y)
392
+ for p in (p0, p1, p2, p3, p4, p5):
393
+ ans = p.integrate(lim)
394
+ for i in range(5):
395
+ reps = {a:1, b:3, y:i}
396
+ assert ans.subs(reps) == p.subs(reps).integrate(lim.subs(reps))
397
+ reps = {a: 3, b:1, y:i}
398
+ assert ans.subs(reps) == p.subs(reps).integrate(lim.subs(reps))
399
+ lim = Tuple(x, y, oo)
400
+ for p in (p0, p1, p2, p3, p4, p5):
401
+ ans = p.integrate(lim)
402
+ for i in range(5):
403
+ reps = {a:1, b:3, y:i}
404
+ assert ans.subs(reps) == p.subs(reps).integrate(lim.subs(reps))
405
+ reps = {a:3, b:1, y:i}
406
+ assert ans.subs(reps) == p.subs(reps).integrate(lim.subs(reps))
407
+
408
+ ans = Piecewise(
409
+ (0, x <= Min(a, b)),
410
+ (x - Min(a, b), x <= b),
411
+ (b - Min(a, b), True))
412
+ for i in (p0, p1, p2, p4):
413
+ assert i.integrate(x) == ans
414
+ assert p3.integrate(x) == Piecewise(
415
+ (0, x < a),
416
+ (-a + x, x <= Max(a, b)),
417
+ (-a + Max(a, b), True))
418
+ assert p5.integrate(x) == Piecewise(
419
+ (0, x <= a),
420
+ (-a + x, x <= Max(a, b)),
421
+ (-a + Max(a, b), True))
422
+
423
+ p1 = Piecewise((0, x < a), (S.Half, x > b), (1, True))
424
+ p2 = Piecewise((S.Half, x > b), (0, x < a), (1, True))
425
+ p3 = Piecewise((0, x < a), (1, x < b), (S.Half, True))
426
+ p4 = Piecewise((S.Half, x > b), (1, x > a), (0, True))
427
+ p5 = Piecewise((1, And(a < x, x < b)), (S.Half, x > b), (0, True))
428
+
429
+ # check values of a=1, b=3 (and reversed) with values
430
+ # of y of 0, 1, 2, 3, 4
431
+ lim = Tuple(x, -oo, y)
432
+ for p in (p1, p2, p3, p4, p5):
433
+ ans = p.integrate(lim)
434
+ for i in range(5):
435
+ reps = {a:1, b:3, y:i}
436
+ assert ans.subs(reps) == p.subs(reps).integrate(lim.subs(reps))
437
+ reps = {a: 3, b:1, y:i}
438
+ assert ans.subs(reps) == p.subs(reps).integrate(lim.subs(reps))
439
+
440
+
441
+ def test_piecewise_integrate5_independent_conditions():
442
+ p = Piecewise((0, Eq(y, 0)), (x*y, True))
443
+ assert integrate(p, (x, 1, 3)) == Piecewise((0, Eq(y, 0)), (4*y, True))
444
+
445
+
446
+ def test_issue_22917():
447
+ p = (Piecewise((0, ITE((x - y > 1) | (2 * x - 2 * y > 1), False,
448
+ ITE(x - y > 1, 2 * y - 2 < -1, 2 * x - 2 * y > 1))),
449
+ (Piecewise((0, ITE(x - y > 1, True, 2 * x - 2 * y > 1)),
450
+ (2 * Piecewise((0, x - y > 1), (y, True)), True)), True))
451
+ + 2 * Piecewise((1, ITE((x - y > 1) | (2 * x - 2 * y > 1), False,
452
+ ITE(x - y > 1, 2 * y - 2 < -1, 2 * x - 2 * y > 1))),
453
+ (Piecewise((1, ITE(x - y > 1, True, 2 * x - 2 * y > 1)),
454
+ (2 * Piecewise((1, x - y > 1), (x, True)), True)), True)))
455
+ assert piecewise_fold(p) == Piecewise((2, (x - y > S.Half) | (x - y > 1)),
456
+ (2*y + 4, x - y > 1),
457
+ (4*x + 2*y, True))
458
+ assert piecewise_fold(p > 1).rewrite(ITE) == ITE((x - y > S.Half) | (x - y > 1), True,
459
+ ITE(x - y > 1, 2*y + 4 > 1, 4*x + 2*y > 1))
460
+
461
+
462
+ def test_piecewise_simplify():
463
+ p = Piecewise(((x**2 + 1)/x**2, Eq(x*(1 + x) - x**2, 0)),
464
+ ((-1)**x*(-1), True))
465
+ assert p.simplify() == \
466
+ Piecewise((zoo, Eq(x, 0)), ((-1)**(x + 1), True))
467
+ # simplify when there are Eq in conditions
468
+ assert Piecewise(
469
+ (a, And(Eq(a, 0), Eq(a + b, 0))), (1, True)).simplify(
470
+ ) == Piecewise(
471
+ (0, And(Eq(a, 0), Eq(b, 0))), (1, True))
472
+ assert Piecewise((2*x*factorial(a)/(factorial(y)*factorial(-y + a)),
473
+ Eq(y, 0) & Eq(-y + a, 0)), (2*factorial(a)/(factorial(y)*factorial(-y
474
+ + a)), Eq(y, 0) & Eq(-y + a, 1)), (0, True)).simplify(
475
+ ) == Piecewise(
476
+ (2*x, And(Eq(a, 0), Eq(y, 0))),
477
+ (2, And(Eq(a, 1), Eq(y, 0))),
478
+ (0, True))
479
+ args = (2, And(Eq(x, 2), Ge(y, 0))), (x, True)
480
+ assert Piecewise(*args).simplify() == Piecewise(*args)
481
+ args = (1, Eq(x, 0)), (sin(x)/x, True)
482
+ assert Piecewise(*args).simplify() == Piecewise(*args)
483
+ assert Piecewise((2 + y, And(Eq(x, 2), Eq(y, 0))), (x, True)
484
+ ).simplify() == x
485
+ # check that x or f(x) are recognized as being Symbol-like for lhs
486
+ args = Tuple((1, Eq(x, 0)), (sin(x) + 1 + x, True))
487
+ ans = x + sin(x) + 1
488
+ f = Function('f')
489
+ assert Piecewise(*args).simplify() == ans
490
+ assert Piecewise(*args.subs(x, f(x))).simplify() == ans.subs(x, f(x))
491
+
492
+ # issue 18634
493
+ d = Symbol("d", integer=True)
494
+ n = Symbol("n", integer=True)
495
+ t = Symbol("t", positive=True)
496
+ expr = Piecewise((-d + 2*n, Eq(1/t, 1)), (t**(1 - 4*n)*t**(4*n - 1)*(-d + 2*n), True))
497
+ assert expr.simplify() == -d + 2*n
498
+
499
+ # issue 22747
500
+ p = Piecewise((0, (t < -2) & (t < -1) & (t < 0)), ((t/2 + 1)*(t +
501
+ 1)*(t + 2), (t < -1) & (t < 0)), ((S.Half - t/2)*(1 - t)*(t + 1),
502
+ (t < -2) & (t < -1) & (t < 1)), ((t + 1)*(-t*(t/2 + 1) + (S.Half
503
+ - t/2)*(1 - t)), (t < -2) & (t < -1) & (t < 0) & (t < 1)), ((t +
504
+ 1)*((S.Half - t/2)*(1 - t) + (t/2 + 1)*(t + 2)), (t < -1) & (t <
505
+ 1)), ((t + 1)*(-t*(t/2 + 1) + (S.Half - t/2)*(1 - t)), (t < -1) &
506
+ (t < 0) & (t < 1)), (0, (t < -2) & (t < -1)), ((t/2 + 1)*(t +
507
+ 1)*(t + 2), t < -1), ((t + 1)*(-t*(t/2 + 1) + (S.Half - t/2)*(t +
508
+ 1)), (t < 0) & ((t < -2) | (t < 0))), ((S.Half - t/2)*(1 - t)*(t
509
+ + 1), (t < 1) & ((t < -2) | (t < 1))), (0, True)) + Piecewise((0,
510
+ (t < -1) & (t < 0) & (t < 1)), ((1 - t)*(t/2 + S.Half)*(t + 1),
511
+ (t < 0) & (t < 1)), ((1 - t)*(1 - t/2)*(2 - t), (t < -1) & (t <
512
+ 0) & (t < 2)), ((1 - t)*((1 - t)*(t/2 + S.Half) + (1 - t/2)*(2 -
513
+ t)), (t < -1) & (t < 0) & (t < 1) & (t < 2)), ((1 - t)*((1 -
514
+ t/2)*(2 - t) + (t/2 + S.Half)*(t + 1)), (t < 0) & (t < 2)), ((1 -
515
+ t)*((1 - t)*(t/2 + S.Half) + (1 - t/2)*(2 - t)), (t < 0) & (t <
516
+ 1) & (t < 2)), (0, (t < -1) & (t < 0)), ((1 - t)*(t/2 +
517
+ S.Half)*(t + 1), t < 0), ((1 - t)*(t*(1 - t/2) + (1 - t)*(t/2 +
518
+ S.Half)), (t < 1) & ((t < -1) | (t < 1))), ((1 - t)*(1 - t/2)*(2
519
+ - t), (t < 2) & ((t < -1) | (t < 2))), (0, True))
520
+ assert p.simplify() == Piecewise(
521
+ (0, t < -2), ((t + 1)*(t + 2)**2/2, t < -1), (-3*t**3/2
522
+ - 5*t**2/2 + 1, t < 0), (3*t**3/2 - 5*t**2/2 + 1, t < 1), ((1 -
523
+ t)*(t - 2)**2/2, t < 2), (0, True))
524
+
525
+ # coverage
526
+ nan = Undefined
527
+ covered = Piecewise((1, x > 3), (2, x < 2), (3, x > 1))
528
+ assert covered.simplify().args == covered.args
529
+ assert Piecewise((1, x < 2), (2, x < 1), (3, True)).simplify(
530
+ ) == Piecewise((1, x < 2), (3, True))
531
+ assert Piecewise((1, x > 2)).simplify() == Piecewise((1, x > 2),
532
+ (nan, True))
533
+ assert Piecewise((1, (x >= 2) & (x < oo))
534
+ ).simplify() == Piecewise((1, (x >= 2) & (x < oo)), (nan, True))
535
+ assert Piecewise((1, x < 2), (2, (x > 1) & (x < 3)), (3, True)
536
+ ). simplify() == Piecewise((1, x < 2), (2, x < 3), (3, True))
537
+ assert Piecewise((1, x < 2), (2, (x <= 3) & (x > 1)), (3, True)
538
+ ).simplify() == Piecewise((1, x < 2), (2, x <= 3), (3, True))
539
+ assert Piecewise((1, x < 2), (2, (x > 2) & (x < 3)), (3, True)
540
+ ).simplify() == Piecewise((1, x < 2), (2, (x > 2) & (x < 3)),
541
+ (3, True))
542
+ assert Piecewise((1, x < 2), (2, (x >= 1) & (x <= 3)), (3, True)
543
+ ).simplify() == Piecewise((1, x < 2), (2, x <= 3), (3, True))
544
+ assert Piecewise((1, x < 1), (2, (x >= 2) & (x <= 3)), (3, True)
545
+ ).simplify() == Piecewise((1, x < 1), (2, (x >= 2) & (x <= 3)),
546
+ (3, True))
547
+
548
+
549
+ def test_piecewise_solve():
550
+ abs2 = Piecewise((-x, x <= 0), (x, x > 0))
551
+ f = abs2.subs(x, x - 2)
552
+ assert solve(f, x) == [2]
553
+ assert solve(f - 1, x) == [1, 3]
554
+
555
+ f = Piecewise(((x - 2)**2, x >= 0), (1, True))
556
+ assert solve(f, x) == [2]
557
+
558
+ g = Piecewise(((x - 5)**5, x >= 4), (f, True))
559
+ assert solve(g, x) == [2, 5]
560
+
561
+ g = Piecewise(((x - 5)**5, x >= 4), (f, x < 4))
562
+ assert solve(g, x) == [2, 5]
563
+
564
+ g = Piecewise(((x - 5)**5, x >= 2), (f, x < 2))
565
+ assert solve(g, x) == [5]
566
+
567
+ g = Piecewise(((x - 5)**5, x >= 2), (f, True))
568
+ assert solve(g, x) == [5]
569
+
570
+ g = Piecewise(((x - 5)**5, x >= 2), (f, True), (10, False))
571
+ assert solve(g, x) == [5]
572
+
573
+ g = Piecewise(((x - 5)**5, x >= 2),
574
+ (-x + 2, x - 2 <= 0), (x - 2, x - 2 > 0))
575
+ assert solve(g, x) == [5]
576
+
577
+ # if no symbol is given the piecewise detection must still work
578
+ assert solve(Piecewise((x - 2, x > 2), (2 - x, True)) - 3) == [-1, 5]
579
+
580
+ f = Piecewise(((x - 2)**2, x >= 0), (0, True))
581
+ raises(NotImplementedError, lambda: solve(f, x))
582
+
583
+ def nona(ans):
584
+ return list(filter(lambda x: x is not S.NaN, ans))
585
+ p = Piecewise((x**2 - 4, x < y), (x - 2, True))
586
+ ans = solve(p, x)
587
+ assert nona([i.subs(y, -2) for i in ans]) == [2]
588
+ assert nona([i.subs(y, 2) for i in ans]) == [-2, 2]
589
+ assert nona([i.subs(y, 3) for i in ans]) == [-2, 2]
590
+ assert ans == [
591
+ Piecewise((-2, y > -2), (S.NaN, True)),
592
+ Piecewise((2, y <= 2), (S.NaN, True)),
593
+ Piecewise((2, y > 2), (S.NaN, True))]
594
+
595
+ # issue 6060
596
+ absxm3 = Piecewise(
597
+ (x - 3, 0 <= x - 3),
598
+ (3 - x, 0 > x - 3)
599
+ )
600
+ assert solve(absxm3 - y, x) == [
601
+ Piecewise((-y + 3, -y < 0), (S.NaN, True)),
602
+ Piecewise((y + 3, y >= 0), (S.NaN, True))]
603
+ p = Symbol('p', positive=True)
604
+ assert solve(absxm3 - p, x) == [-p + 3, p + 3]
605
+
606
+ # issue 6989
607
+ f = Function('f')
608
+ assert solve(Eq(-f(x), Piecewise((1, x > 0), (0, True))), f(x)) == \
609
+ [Piecewise((-1, x > 0), (0, True))]
610
+
611
+ # issue 8587
612
+ f = Piecewise((2*x**2, And(0 < x, x < 1)), (2, True))
613
+ assert solve(f - 1) == [1/sqrt(2)]
614
+
615
+
616
+ def test_piecewise_fold():
617
+ p = Piecewise((x, x < 1), (1, 1 <= x))
618
+
619
+ assert piecewise_fold(x*p) == Piecewise((x**2, x < 1), (x, 1 <= x))
620
+ assert piecewise_fold(p + p) == Piecewise((2*x, x < 1), (2, 1 <= x))
621
+ assert piecewise_fold(Piecewise((1, x < 0), (2, True))
622
+ + Piecewise((10, x < 0), (-10, True))) == \
623
+ Piecewise((11, x < 0), (-8, True))
624
+
625
+ p1 = Piecewise((0, x < 0), (x, x <= 1), (0, True))
626
+ p2 = Piecewise((0, x < 0), (1 - x, x <= 1), (0, True))
627
+
628
+ p = 4*p1 + 2*p2
629
+ assert integrate(
630
+ piecewise_fold(p), (x, -oo, oo)) == integrate(2*x + 2, (x, 0, 1))
631
+
632
+ assert piecewise_fold(
633
+ Piecewise((1, y <= 0), (-Piecewise((2, y >= 0)), True)
634
+ )) == Piecewise((1, y <= 0), (-2, y >= 0))
635
+
636
+ assert piecewise_fold(Piecewise((x, ITE(x > 0, y < 1, y > 1)))
637
+ ) == Piecewise((x, ((x <= 0) | (y < 1)) & ((x > 0) | (y > 1))))
638
+
639
+ a, b = (Piecewise((2, Eq(x, 0)), (0, True)),
640
+ Piecewise((x, Eq(-x + y, 0)), (1, Eq(-x + y, 1)), (0, True)))
641
+ assert piecewise_fold(Mul(a, b, evaluate=False)
642
+ ) == piecewise_fold(Mul(b, a, evaluate=False))
643
+
644
+
645
+ def test_piecewise_fold_piecewise_in_cond():
646
+ p1 = Piecewise((cos(x), x < 0), (0, True))
647
+ p2 = Piecewise((0, Eq(p1, 0)), (p1 / Abs(p1), True))
648
+ assert p2.subs(x, -pi/2) == 0
649
+ assert p2.subs(x, 1) == 0
650
+ assert p2.subs(x, -pi/4) == 1
651
+ p4 = Piecewise((0, Eq(p1, 0)), (1,True))
652
+ ans = piecewise_fold(p4)
653
+ for i in range(-1, 1):
654
+ assert ans.subs(x, i) == p4.subs(x, i)
655
+
656
+ r1 = 1 < Piecewise((1, x < 1), (3, True))
657
+ ans = piecewise_fold(r1)
658
+ for i in range(2):
659
+ assert ans.subs(x, i) == r1.subs(x, i)
660
+
661
+ p5 = Piecewise((1, x < 0), (3, True))
662
+ p6 = Piecewise((1, x < 1), (3, True))
663
+ p7 = Piecewise((1, p5 < p6), (0, True))
664
+ ans = piecewise_fold(p7)
665
+ for i in range(-1, 2):
666
+ assert ans.subs(x, i) == p7.subs(x, i)
667
+
668
+
669
+ def test_piecewise_fold_piecewise_in_cond_2():
670
+ p1 = Piecewise((cos(x), x < 0), (0, True))
671
+ p2 = Piecewise((0, Eq(p1, 0)), (1 / p1, True))
672
+ p3 = Piecewise(
673
+ (0, (x >= 0) | Eq(cos(x), 0)),
674
+ (1/cos(x), x < 0),
675
+ (zoo, True)) # redundant b/c all x are already covered
676
+ assert(piecewise_fold(p2) == p3)
677
+
678
+
679
+ def test_piecewise_fold_expand():
680
+ p1 = Piecewise((1, Interval(0, 1, False, True).contains(x)), (0, True))
681
+
682
+ p2 = piecewise_fold(expand((1 - x)*p1))
683
+ cond = ((x >= 0) & (x < 1))
684
+ assert piecewise_fold(expand((1 - x)*p1), evaluate=False
685
+ ) == Piecewise((1 - x, cond), (-x, cond), (1, cond), (0, True), evaluate=False)
686
+ assert piecewise_fold(expand((1 - x)*p1), evaluate=None
687
+ ) == Piecewise((1 - x, cond), (0, True))
688
+ assert p2 == Piecewise((1 - x, cond), (0, True))
689
+ assert p2 == expand(piecewise_fold((1 - x)*p1))
690
+
691
+
692
+ def test_piecewise_duplicate():
693
+ p = Piecewise((x, x < -10), (x**2, x <= -1), (x, 1 < x))
694
+ assert p == Piecewise(*p.args)
695
+
696
+
697
+ def test_doit():
698
+ p1 = Piecewise((x, x < 1), (x**2, -1 <= x), (x, 3 < x))
699
+ p2 = Piecewise((x, x < 1), (Integral(2 * x), -1 <= x), (x, 3 < x))
700
+ assert p2.doit() == p1
701
+ assert p2.doit(deep=False) == p2
702
+ # issue 17165
703
+ p1 = Sum(y**x, (x, -1, oo)).doit()
704
+ assert p1.doit() == p1
705
+
706
+
707
+ def test_piecewise_interval():
708
+ p1 = Piecewise((x, Interval(0, 1).contains(x)), (0, True))
709
+ assert p1.subs(x, -0.5) == 0
710
+ assert p1.subs(x, 0.5) == 0.5
711
+ assert p1.diff(x) == Piecewise((1, Interval(0, 1).contains(x)), (0, True))
712
+ assert integrate(p1, x) == Piecewise(
713
+ (0, x <= 0),
714
+ (x**2/2, x <= 1),
715
+ (S.Half, True))
716
+
717
+
718
+ def test_piecewise_exclusive():
719
+ p = Piecewise((0, x < 0), (S.Half, x <= 0), (1, True))
720
+ assert piecewise_exclusive(p) == Piecewise((0, x < 0), (S.Half, Eq(x, 0)),
721
+ (1, x > 0), evaluate=False)
722
+ assert piecewise_exclusive(p + 2) == Piecewise((0, x < 0), (S.Half, Eq(x, 0)),
723
+ (1, x > 0), evaluate=False) + 2
724
+ assert piecewise_exclusive(Piecewise((1, y <= 0),
725
+ (-Piecewise((2, y >= 0)), True))) == \
726
+ Piecewise((1, y <= 0),
727
+ (-Piecewise((2, y >= 0),
728
+ (S.NaN, y < 0), evaluate=False), y > 0), evaluate=False)
729
+ assert piecewise_exclusive(Piecewise((1, x > y))) == Piecewise((1, x > y),
730
+ (S.NaN, x <= y),
731
+ evaluate=False)
732
+ assert piecewise_exclusive(Piecewise((1, x > y)),
733
+ skip_nan=True) == Piecewise((1, x > y))
734
+
735
+ xr, yr = symbols('xr, yr', real=True)
736
+
737
+ p1 = Piecewise((1, xr < 0), (2, True), evaluate=False)
738
+ p1x = Piecewise((1, xr < 0), (2, xr >= 0), evaluate=False)
739
+
740
+ p2 = Piecewise((p1, yr < 0), (3, True), evaluate=False)
741
+ p2x = Piecewise((p1, yr < 0), (3, yr >= 0), evaluate=False)
742
+ p2xx = Piecewise((p1x, yr < 0), (3, yr >= 0), evaluate=False)
743
+
744
+ assert piecewise_exclusive(p2) == p2xx
745
+ assert piecewise_exclusive(p2, deep=False) == p2x
746
+
747
+
748
+ def test_piecewise_collapse():
749
+ assert Piecewise((x, True)) == x
750
+ a = x < 1
751
+ assert Piecewise((x, a), (x + 1, a)) == Piecewise((x, a))
752
+ assert Piecewise((x, a), (x + 1, a.reversed)) == Piecewise((x, a))
753
+ b = x < 5
754
+ def canonical(i):
755
+ if isinstance(i, Piecewise):
756
+ return Piecewise(*i.args)
757
+ return i
758
+ for args in [
759
+ ((1, a), (Piecewise((2, a), (3, b)), b)),
760
+ ((1, a), (Piecewise((2, a), (3, b.reversed)), b)),
761
+ ((1, a), (Piecewise((2, a), (3, b)), b), (4, True)),
762
+ ((1, a), (Piecewise((2, a), (3, b), (4, True)), b)),
763
+ ((1, a), (Piecewise((2, a), (3, b), (4, True)), b), (5, True))]:
764
+ for i in (0, 2, 10):
765
+ assert canonical(
766
+ Piecewise(*args, evaluate=False).subs(x, i)
767
+ ) == canonical(Piecewise(*args).subs(x, i))
768
+ r1, r2, r3, r4 = symbols('r1:5')
769
+ a = x < r1
770
+ b = x < r2
771
+ c = x < r3
772
+ d = x < r4
773
+ assert Piecewise((1, a), (Piecewise(
774
+ (2, a), (3, b), (4, c)), b), (5, c)
775
+ ) == Piecewise((1, a), (3, b), (5, c))
776
+ assert Piecewise((1, a), (Piecewise(
777
+ (2, a), (3, b), (4, c), (6, True)), c), (5, d)
778
+ ) == Piecewise((1, a), (Piecewise(
779
+ (3, b), (4, c)), c), (5, d))
780
+ assert Piecewise((1, Or(a, d)), (Piecewise(
781
+ (2, d), (3, b), (4, c)), b), (5, c)
782
+ ) == Piecewise((1, Or(a, d)), (Piecewise(
783
+ (2, d), (3, b)), b), (5, c))
784
+ assert Piecewise((1, c), (2, ~c), (3, S.true)
785
+ ) == Piecewise((1, c), (2, S.true))
786
+ assert Piecewise((1, c), (2, And(~c, b)), (3,True)
787
+ ) == Piecewise((1, c), (2, b), (3, True))
788
+ assert Piecewise((1, c), (2, Or(~c, b)), (3,True)
789
+ ).subs(dict(zip((r1, r2, r3, r4, x), (1, 2, 3, 4, 3.5)))) == 2
790
+ assert Piecewise((1, c), (2, ~c)) == Piecewise((1, c), (2, True))
791
+
792
+
793
+ def test_piecewise_lambdify():
794
+ p = Piecewise(
795
+ (x**2, x < 0),
796
+ (x, Interval(0, 1, False, True).contains(x)),
797
+ (2 - x, x >= 1),
798
+ (0, True)
799
+ )
800
+
801
+ f = lambdify(x, p)
802
+ assert f(-2.0) == 4.0
803
+ assert f(0.0) == 0.0
804
+ assert f(0.5) == 0.5
805
+ assert f(2.0) == 0.0
806
+
807
+
808
+ def test_piecewise_series():
809
+ from sympy.series.order import O
810
+ p1 = Piecewise((sin(x), x < 0), (cos(x), x > 0))
811
+ p2 = Piecewise((x + O(x**2), x < 0), (1 + O(x**2), x > 0))
812
+ assert p1.nseries(x, n=2) == p2
813
+
814
+
815
+ def test_piecewise_as_leading_term():
816
+ p1 = Piecewise((1/x, x > 1), (0, True))
817
+ p2 = Piecewise((x, x > 1), (0, True))
818
+ p3 = Piecewise((1/x, x > 1), (x, True))
819
+ p4 = Piecewise((x, x > 1), (1/x, True))
820
+ p5 = Piecewise((1/x, x > 1), (x, True))
821
+ p6 = Piecewise((1/x, x < 1), (x, True))
822
+ p7 = Piecewise((x, x < 1), (1/x, True))
823
+ p8 = Piecewise((x, x > 1), (1/x, True))
824
+ assert p1.as_leading_term(x) == 0
825
+ assert p2.as_leading_term(x) == 0
826
+ assert p3.as_leading_term(x) == x
827
+ assert p4.as_leading_term(x) == 1/x
828
+ assert p5.as_leading_term(x) == x
829
+ assert p6.as_leading_term(x) == 1/x
830
+ assert p7.as_leading_term(x) == x
831
+ assert p8.as_leading_term(x) == 1/x
832
+
833
+
834
+ def test_piecewise_complex():
835
+ p1 = Piecewise((2, x < 0), (1, 0 <= x))
836
+ p2 = Piecewise((2*I, x < 0), (I, 0 <= x))
837
+ p3 = Piecewise((I*x, x > 1), (1 + I, True))
838
+ p4 = Piecewise((-I*conjugate(x), x > 1), (1 - I, True))
839
+
840
+ assert conjugate(p1) == p1
841
+ assert conjugate(p2) == piecewise_fold(-p2)
842
+ assert conjugate(p3) == p4
843
+
844
+ assert p1.is_imaginary is False
845
+ assert p1.is_real is True
846
+ assert p2.is_imaginary is True
847
+ assert p2.is_real is False
848
+ assert p3.is_imaginary is None
849
+ assert p3.is_real is None
850
+
851
+ assert p1.as_real_imag() == (p1, 0)
852
+ assert p2.as_real_imag() == (0, -I*p2)
853
+
854
+
855
+ def test_conjugate_transpose():
856
+ A, B = symbols("A B", commutative=False)
857
+ p = Piecewise((A*B**2, x > 0), (A**2*B, True))
858
+ assert p.adjoint() == \
859
+ Piecewise((adjoint(A*B**2), x > 0), (adjoint(A**2*B), True))
860
+ assert p.conjugate() == \
861
+ Piecewise((conjugate(A*B**2), x > 0), (conjugate(A**2*B), True))
862
+ assert p.transpose() == \
863
+ Piecewise((transpose(A*B**2), x > 0), (transpose(A**2*B), True))
864
+
865
+
866
+ def test_piecewise_evaluate():
867
+ assert Piecewise((x, True)) == x
868
+ assert Piecewise((x, True), evaluate=True) == x
869
+ assert Piecewise((1, Eq(1, x))).args == ((1, Eq(x, 1)),)
870
+ assert Piecewise((1, Eq(1, x)), evaluate=False).args == (
871
+ (1, Eq(1, x)),)
872
+ # like the additive and multiplicative identities that
873
+ # cannot be kept in Add/Mul, we also do not keep a single True
874
+ p = Piecewise((x, True), evaluate=False)
875
+ assert p == x
876
+
877
+
878
+ def test_as_expr_set_pairs():
879
+ assert Piecewise((x, x > 0), (-x, x <= 0)).as_expr_set_pairs() == \
880
+ [(x, Interval(0, oo, True, True)), (-x, Interval(-oo, 0))]
881
+
882
+ assert Piecewise(((x - 2)**2, x >= 0), (0, True)).as_expr_set_pairs() == \
883
+ [((x - 2)**2, Interval(0, oo)), (0, Interval(-oo, 0, True, True))]
884
+
885
+
886
+ def test_S_srepr_is_identity():
887
+ p = Piecewise((10, Eq(x, 0)), (12, True))
888
+ q = S(srepr(p))
889
+ assert p == q
890
+
891
+
892
+ def test_issue_12587():
893
+ # sort holes into intervals
894
+ p = Piecewise((1, x > 4), (2, Not((x <= 3) & (x > -1))), (3, True))
895
+ assert p.integrate((x, -5, 5)) == 23
896
+ p = Piecewise((1, x > 1), (2, x < y), (3, True))
897
+ lim = x, -3, 3
898
+ ans = p.integrate(lim)
899
+ for i in range(-1, 3):
900
+ assert ans.subs(y, i) == p.subs(y, i).integrate(lim)
901
+
902
+
903
+ def test_issue_11045():
904
+ assert integrate(1/(x*sqrt(x**2 - 1)), (x, 1, 2)) == pi/3
905
+
906
+ # handle And with Or arguments
907
+ assert Piecewise((1, And(Or(x < 1, x > 3), x < 2)), (0, True)
908
+ ).integrate((x, 0, 3)) == 1
909
+
910
+ # hidden false
911
+ assert Piecewise((1, x > 1), (2, x > x + 1), (3, True)
912
+ ).integrate((x, 0, 3)) == 5
913
+ # targetcond is Eq
914
+ assert Piecewise((1, x > 1), (2, Eq(1, x)), (3, True)
915
+ ).integrate((x, 0, 4)) == 6
916
+ # And has Relational needing to be solved
917
+ assert Piecewise((1, And(2*x > x + 1, x < 2)), (0, True)
918
+ ).integrate((x, 0, 3)) == 1
919
+ # Or has Relational needing to be solved
920
+ assert Piecewise((1, Or(2*x > x + 2, x < 1)), (0, True)
921
+ ).integrate((x, 0, 3)) == 2
922
+ # ignore hidden false (handled in canonicalization)
923
+ assert Piecewise((1, x > 1), (2, x > x + 1), (3, True)
924
+ ).integrate((x, 0, 3)) == 5
925
+ # watch for hidden True Piecewise
926
+ assert Piecewise((2, Eq(1 - x, x*(1/x - 1))), (0, True)
927
+ ).integrate((x, 0, 3)) == 6
928
+
929
+ # overlapping conditions of targetcond are recognized and ignored;
930
+ # the condition x > 3 will be pre-empted by the first condition
931
+ assert Piecewise((1, Or(x < 1, x > 2)), (2, x > 3), (3, True)
932
+ ).integrate((x, 0, 4)) == 6
933
+
934
+ # convert Ne to Or
935
+ assert Piecewise((1, Ne(x, 0)), (2, True)
936
+ ).integrate((x, -1, 1)) == 2
937
+
938
+ # no default but well defined
939
+ assert Piecewise((x, (x > 1) & (x < 3)), (1, (x < 4))
940
+ ).integrate((x, 1, 4)) == 5
941
+
942
+ p = Piecewise((x, (x > 1) & (x < 3)), (1, (x < 4)))
943
+ nan = Undefined
944
+ i = p.integrate((x, 1, y))
945
+ assert i == Piecewise(
946
+ (y - 1, y < 1),
947
+ (Min(3, y)**2/2 - Min(3, y) + Min(4, y) - S.Half,
948
+ y <= Min(4, y)),
949
+ (nan, True))
950
+ assert p.integrate((x, 1, -1)) == i.subs(y, -1)
951
+ assert p.integrate((x, 1, 4)) == 5
952
+ assert p.integrate((x, 1, 5)) is nan
953
+
954
+ # handle Not
955
+ p = Piecewise((1, x > 1), (2, Not(And(x > 1, x< 3))), (3, True))
956
+ assert p.integrate((x, 0, 3)) == 4
957
+
958
+ # handle updating of int_expr when there is overlap
959
+ p = Piecewise(
960
+ (1, And(5 > x, x > 1)),
961
+ (2, Or(x < 3, x > 7)),
962
+ (4, x < 8))
963
+ assert p.integrate((x, 0, 10)) == 20
964
+
965
+ # And with Eq arg handling
966
+ assert Piecewise((1, x < 1), (2, And(Eq(x, 3), x > 1))
967
+ ).integrate((x, 0, 3)) is S.NaN
968
+ assert Piecewise((1, x < 1), (2, And(Eq(x, 3), x > 1)), (3, True)
969
+ ).integrate((x, 0, 3)) == 7
970
+ assert Piecewise((1, x < 0), (2, And(Eq(x, 3), x < 1)), (3, True)
971
+ ).integrate((x, -1, 1)) == 4
972
+ # middle condition doesn't matter: it's a zero width interval
973
+ assert Piecewise((1, x < 1), (2, Eq(x, 3) & (y < x)), (3, True)
974
+ ).integrate((x, 0, 3)) == 7
975
+
976
+
977
+ def test_holes():
978
+ nan = Undefined
979
+ assert Piecewise((1, x < 2)).integrate(x) == Piecewise(
980
+ (x, x < 2), (nan, True))
981
+ assert Piecewise((1, And(x > 1, x < 2))).integrate(x) == Piecewise(
982
+ (nan, x < 1), (x, x < 2), (nan, True))
983
+ assert Piecewise((1, And(x > 1, x < 2))).integrate((x, 0, 3)) is nan
984
+ assert Piecewise((1, And(x > 0, x < 4))).integrate((x, 1, 3)) == 2
985
+
986
+ # this also tests that the integrate method is used on non-Piecwise
987
+ # arguments in _eval_integral
988
+ A, B = symbols("A B")
989
+ a, b = symbols('a b', real=True)
990
+ assert Piecewise((A, And(x < 0, a < 1)), (B, Or(x < 1, a > 2))
991
+ ).integrate(x) == Piecewise(
992
+ (B*x, (a > 2)),
993
+ (Piecewise((A*x, x < 0), (B*x, x < 1), (nan, True)), a < 1),
994
+ (Piecewise((B*x, x < 1), (nan, True)), True))
995
+
996
+
997
+ def test_issue_11922():
998
+ def f(x):
999
+ return Piecewise((0, x < -1), (1 - x**2, x < 1), (0, True))
1000
+ autocorr = lambda k: (
1001
+ f(x) * f(x + k)).integrate((x, -1, 1))
1002
+ assert autocorr(1.9) > 0
1003
+ k = symbols('k')
1004
+ good_autocorr = lambda k: (
1005
+ (1 - x**2) * f(x + k)).integrate((x, -1, 1))
1006
+ a = good_autocorr(k)
1007
+ assert a.subs(k, 3) == 0
1008
+ k = symbols('k', positive=True)
1009
+ a = good_autocorr(k)
1010
+ assert a.subs(k, 3) == 0
1011
+ assert Piecewise((0, x < 1), (10, (x >= 1))
1012
+ ).integrate() == Piecewise((0, x < 1), (10*x - 10, True))
1013
+
1014
+
1015
+ def test_issue_5227():
1016
+ f = 0.0032513612725229*Piecewise((0, x < -80.8461538461539),
1017
+ (-0.0160799238820171*x + 1.33215984776403, x < 2),
1018
+ (Piecewise((0.3, x > 123), (0.7, True)) +
1019
+ Piecewise((0.4, x > 2), (0.6, True)), x <=
1020
+ 123), (-0.00817409766454352*x + 2.10541401273885, x <
1021
+ 380.571428571429), (0, True))
1022
+ i = integrate(f, (x, -oo, oo))
1023
+ assert i == Integral(f, (x, -oo, oo)).doit()
1024
+ assert str(i) == '1.00195081676351'
1025
+ assert Piecewise((1, x - y < 0), (0, True)
1026
+ ).integrate(y) == Piecewise((0, y <= x), (-x + y, True))
1027
+
1028
+
1029
+ def test_issue_10137():
1030
+ a = Symbol('a', real=True)
1031
+ b = Symbol('b', real=True)
1032
+ x = Symbol('x', real=True)
1033
+ y = Symbol('y', real=True)
1034
+ p0 = Piecewise((0, Or(x < a, x > b)), (1, True))
1035
+ p1 = Piecewise((0, Or(a > x, b < x)), (1, True))
1036
+ assert integrate(p0, (x, y, oo)) == integrate(p1, (x, y, oo))
1037
+ p3 = Piecewise((1, And(0 < x, x < a)), (0, True))
1038
+ p4 = Piecewise((1, And(a > x, x > 0)), (0, True))
1039
+ ip3 = integrate(p3, x)
1040
+ assert ip3 == Piecewise(
1041
+ (0, x <= 0),
1042
+ (x, x <= Max(0, a)),
1043
+ (Max(0, a), True))
1044
+ ip4 = integrate(p4, x)
1045
+ assert ip4 == ip3
1046
+ assert p3.integrate((x, 2, 4)) == Min(4, Max(2, a)) - 2
1047
+ assert p4.integrate((x, 2, 4)) == Min(4, Max(2, a)) - 2
1048
+
1049
+
1050
+ def test_stackoverflow_43852159():
1051
+ f = lambda x: Piecewise((1, (x >= -1) & (x <= 1)), (0, True))
1052
+ Conv = lambda x: integrate(f(x - y)*f(y), (y, -oo, +oo))
1053
+ cx = Conv(x)
1054
+ assert cx.subs(x, -1.5) == cx.subs(x, 1.5)
1055
+ assert cx.subs(x, 3) == 0
1056
+ assert piecewise_fold(f(x - y)*f(y)) == Piecewise(
1057
+ (1, (y >= -1) & (y <= 1) & (x - y >= -1) & (x - y <= 1)),
1058
+ (0, True))
1059
+
1060
+
1061
+ def test_issue_12557():
1062
+ '''
1063
+ # 3200 seconds to compute the fourier part of issue
1064
+ import sympy as sym
1065
+ x,y,z,t = sym.symbols('x y z t')
1066
+ k = sym.symbols("k", integer=True)
1067
+ fourier = sym.fourier_series(sym.cos(k*x)*sym.sqrt(x**2),
1068
+ (x, -sym.pi, sym.pi))
1069
+ assert fourier == FourierSeries(
1070
+ sqrt(x**2)*cos(k*x), (x, -pi, pi), (Piecewise((pi**2,
1071
+ Eq(k, 0)), (2*(-1)**k/k**2 - 2/k**2, True))/(2*pi),
1072
+ SeqFormula(Piecewise((pi**2, (Eq(_n, 0) & Eq(k, 0)) | (Eq(_n, 0) &
1073
+ Eq(_n, k) & Eq(k, 0)) | (Eq(_n, 0) & Eq(k, 0) & Eq(_n, -k)) | (Eq(_n,
1074
+ 0) & Eq(_n, k) & Eq(k, 0) & Eq(_n, -k))), (pi**2/2, Eq(_n, k) | Eq(_n,
1075
+ -k) | (Eq(_n, 0) & Eq(_n, k)) | (Eq(_n, k) & Eq(k, 0)) | (Eq(_n, 0) &
1076
+ Eq(_n, -k)) | (Eq(_n, k) & Eq(_n, -k)) | (Eq(k, 0) & Eq(_n, -k)) |
1077
+ (Eq(_n, 0) & Eq(_n, k) & Eq(_n, -k)) | (Eq(_n, k) & Eq(k, 0) & Eq(_n,
1078
+ -k))), ((-1)**k*pi**2*_n**3*sin(pi*_n)/(pi*_n**4 - 2*pi*_n**2*k**2 +
1079
+ pi*k**4) - (-1)**k*pi**2*_n**3*sin(pi*_n)/(-pi*_n**4 + 2*pi*_n**2*k**2
1080
+ - pi*k**4) + (-1)**k*pi*_n**2*cos(pi*_n)/(pi*_n**4 - 2*pi*_n**2*k**2 +
1081
+ pi*k**4) - (-1)**k*pi*_n**2*cos(pi*_n)/(-pi*_n**4 + 2*pi*_n**2*k**2 -
1082
+ pi*k**4) - (-1)**k*pi**2*_n*k**2*sin(pi*_n)/(pi*_n**4 -
1083
+ 2*pi*_n**2*k**2 + pi*k**4) +
1084
+ (-1)**k*pi**2*_n*k**2*sin(pi*_n)/(-pi*_n**4 + 2*pi*_n**2*k**2 -
1085
+ pi*k**4) + (-1)**k*pi*k**2*cos(pi*_n)/(pi*_n**4 - 2*pi*_n**2*k**2 +
1086
+ pi*k**4) - (-1)**k*pi*k**2*cos(pi*_n)/(-pi*_n**4 + 2*pi*_n**2*k**2 -
1087
+ pi*k**4) - (2*_n**2 + 2*k**2)/(_n**4 - 2*_n**2*k**2 + k**4),
1088
+ True))*cos(_n*x)/pi, (_n, 1, oo)), SeqFormula(0, (_k, 1, oo))))
1089
+ '''
1090
+ x = symbols("x", real=True)
1091
+ k = symbols('k', integer=True, finite=True)
1092
+ abs2 = lambda x: Piecewise((-x, x <= 0), (x, x > 0))
1093
+ assert integrate(abs2(x), (x, -pi, pi)) == pi**2
1094
+ func = cos(k*x)*sqrt(x**2)
1095
+ assert integrate(func, (x, -pi, pi)) == Piecewise(
1096
+ (2*(-1)**k/k**2 - 2/k**2, Ne(k, 0)), (pi**2, True))
1097
+
1098
+ def test_issue_6900():
1099
+ from itertools import permutations
1100
+ t0, t1, T, t = symbols('t0, t1 T t')
1101
+ f = Piecewise((0, t < t0), (x, And(t0 <= t, t < t1)), (0, t >= t1))
1102
+ g = f.integrate(t)
1103
+ assert g == Piecewise(
1104
+ (0, t <= t0),
1105
+ (t*x - t0*x, t <= Max(t0, t1)),
1106
+ (-t0*x + x*Max(t0, t1), True))
1107
+ for i in permutations(range(2)):
1108
+ reps = dict(zip((t0,t1), i))
1109
+ for tt in range(-1,3):
1110
+ assert (g.xreplace(reps).subs(t,tt) ==
1111
+ f.xreplace(reps).integrate(t).subs(t,tt))
1112
+ lim = Tuple(t, t0, T)
1113
+ g = f.integrate(lim)
1114
+ ans = Piecewise(
1115
+ (-t0*x + x*Min(T, Max(t0, t1)), T > t0),
1116
+ (0, True))
1117
+ for i in permutations(range(3)):
1118
+ reps = dict(zip((t0,t1,T), i))
1119
+ tru = f.xreplace(reps).integrate(lim.xreplace(reps))
1120
+ assert tru == ans.xreplace(reps)
1121
+ assert g == ans
1122
+
1123
+
1124
+ def test_issue_10122():
1125
+ assert solve(abs(x) + abs(x - 1) - 1 > 0, x
1126
+ ) == Or(And(-oo < x, x < S.Zero), And(S.One < x, x < oo))
1127
+
1128
+
1129
+ def test_issue_4313():
1130
+ u = Piecewise((0, x <= 0), (1, x >= a), (x/a, True))
1131
+ e = (u - u.subs(x, y))**2/(x - y)**2
1132
+ M = Max(0, a)
1133
+ assert integrate(e, x).expand() == Piecewise(
1134
+ (Piecewise(
1135
+ (0, x <= 0),
1136
+ (-y**2/(a**2*x - a**2*y) + x/a**2 - 2*y*log(-y)/a**2 +
1137
+ 2*y*log(x - y)/a**2 - y/a**2, x <= M),
1138
+ (-y**2/(-a**2*y + a**2*M) + 1/(-y + M) -
1139
+ 1/(x - y) - 2*y*log(-y)/a**2 + 2*y*log(-y +
1140
+ M)/a**2 - y/a**2 + M/a**2, True)),
1141
+ ((a <= y) & (y <= 0)) | ((y <= 0) & (y > -oo))),
1142
+ (Piecewise(
1143
+ (-1/(x - y), x <= 0),
1144
+ (-a**2/(a**2*x - a**2*y) + 2*a*y/(a**2*x - a**2*y) -
1145
+ y**2/(a**2*x - a**2*y) + 2*log(-y)/a - 2*log(x - y)/a +
1146
+ 2/a + x/a**2 - 2*y*log(-y)/a**2 + 2*y*log(x - y)/a**2 -
1147
+ y/a**2, x <= M),
1148
+ (-a**2/(-a**2*y + a**2*M) + 2*a*y/(-a**2*y +
1149
+ a**2*M) - y**2/(-a**2*y + a**2*M) +
1150
+ 2*log(-y)/a - 2*log(-y + M)/a + 2/a -
1151
+ 2*y*log(-y)/a**2 + 2*y*log(-y + M)/a**2 -
1152
+ y/a**2 + M/a**2, True)),
1153
+ a <= y),
1154
+ (Piecewise(
1155
+ (-y**2/(a**2*x - a**2*y), x <= 0),
1156
+ (x/a**2 + y/a**2, x <= M),
1157
+ (a**2/(-a**2*y + a**2*M) -
1158
+ a**2/(a**2*x - a**2*y) - 2*a*y/(-a**2*y + a**2*M) +
1159
+ 2*a*y/(a**2*x - a**2*y) + y**2/(-a**2*y + a**2*M) -
1160
+ y**2/(a**2*x - a**2*y) + y/a**2 + M/a**2, True)),
1161
+ True))
1162
+
1163
+
1164
+ def test__intervals():
1165
+ assert Piecewise((x + 2, Eq(x, 3)))._intervals(x) == (True, [])
1166
+ assert Piecewise(
1167
+ (1, x > x + 1),
1168
+ (Piecewise((1, x < x + 1)), 2*x < 2*x + 1),
1169
+ (1, True))._intervals(x) == (True, [(-oo, oo, 1, 1)])
1170
+ assert Piecewise((1, Ne(x, I)), (0, True))._intervals(x) == (True,
1171
+ [(-oo, oo, 1, 0)])
1172
+ assert Piecewise((-cos(x), sin(x) >= 0), (cos(x), True)
1173
+ )._intervals(x) == (True,
1174
+ [(0, pi, -cos(x), 0), (-oo, oo, cos(x), 1)])
1175
+ # the following tests that duplicates are removed and that non-Eq
1176
+ # generated zero-width intervals are removed
1177
+ assert Piecewise((1, Abs(x**(-2)) > 1), (0, True)
1178
+ )._intervals(x) == (True,
1179
+ [(-1, 0, 1, 0), (0, 1, 1, 0), (-oo, oo, 0, 1)])
1180
+
1181
+
1182
+ def test_containment():
1183
+ a, b, c, d, e = [1, 2, 3, 4, 5]
1184
+ p = (Piecewise((d, x > 1), (e, True))*
1185
+ Piecewise((a, Abs(x - 1) < 1), (b, Abs(x - 2) < 2), (c, True)))
1186
+ assert p.integrate(x).diff(x) == Piecewise(
1187
+ (c*e, x <= 0),
1188
+ (a*e, x <= 1),
1189
+ (a*d, x < 2), # this is what we want to get right
1190
+ (b*d, x < 4),
1191
+ (c*d, True))
1192
+
1193
+
1194
+ def test_piecewise_with_DiracDelta():
1195
+ d1 = DiracDelta(x - 1)
1196
+ assert integrate(d1, (x, -oo, oo)) == 1
1197
+ assert integrate(d1, (x, 0, 2)) == 1
1198
+ assert Piecewise((d1, Eq(x, 2)), (0, True)).integrate(x) == 0
1199
+ assert Piecewise((d1, x < 2), (0, True)).integrate(x) == Piecewise(
1200
+ (Heaviside(x - 1), x < 2), (1, True))
1201
+ # TODO raise error if function is discontinuous at limit of
1202
+ # integration, e.g. integrate(d1, (x, -2, 1)) or Piecewise(
1203
+ # (d1, Eq(x, 1)
1204
+
1205
+
1206
+ def test_issue_10258():
1207
+ assert Piecewise((0, x < 1), (1, True)).is_zero is None
1208
+ assert Piecewise((-1, x < 1), (1, True)).is_zero is False
1209
+ a = Symbol('a', zero=True)
1210
+ assert Piecewise((0, x < 1), (a, True)).is_zero
1211
+ assert Piecewise((1, x < 1), (a, x < 3)).is_zero is None
1212
+ a = Symbol('a')
1213
+ assert Piecewise((0, x < 1), (a, True)).is_zero is None
1214
+ assert Piecewise((0, x < 1), (1, True)).is_nonzero is None
1215
+ assert Piecewise((1, x < 1), (2, True)).is_nonzero
1216
+ assert Piecewise((0, x < 1), (oo, True)).is_finite is None
1217
+ assert Piecewise((0, x < 1), (1, True)).is_finite
1218
+ b = Basic()
1219
+ assert Piecewise((b, x < 1)).is_finite is None
1220
+
1221
+ # 10258
1222
+ c = Piecewise((1, x < 0), (2, True)) < 3
1223
+ assert c != True
1224
+ assert piecewise_fold(c) == True
1225
+
1226
+
1227
+ def test_issue_10087():
1228
+ a, b = Piecewise((x, x > 1), (2, True)), Piecewise((x, x > 3), (3, True))
1229
+ m = a*b
1230
+ f = piecewise_fold(m)
1231
+ for i in (0, 2, 4):
1232
+ assert m.subs(x, i) == f.subs(x, i)
1233
+ m = a + b
1234
+ f = piecewise_fold(m)
1235
+ for i in (0, 2, 4):
1236
+ assert m.subs(x, i) == f.subs(x, i)
1237
+
1238
+
1239
+ def test_issue_8919():
1240
+ c = symbols('c:5')
1241
+ x = symbols("x")
1242
+ f1 = Piecewise((c[1], x < 1), (c[2], True))
1243
+ f2 = Piecewise((c[3], x < Rational(1, 3)), (c[4], True))
1244
+ assert integrate(f1*f2, (x, 0, 2)
1245
+ ) == c[1]*c[3]/3 + 2*c[1]*c[4]/3 + c[2]*c[4]
1246
+ f1 = Piecewise((0, x < 1), (2, True))
1247
+ f2 = Piecewise((3, x < 2), (0, True))
1248
+ assert integrate(f1*f2, (x, 0, 3)) == 6
1249
+
1250
+ y = symbols("y", positive=True)
1251
+ a, b, c, x, z = symbols("a,b,c,x,z", real=True)
1252
+ I = Integral(Piecewise(
1253
+ (0, (x >= y) | (x < 0) | (b > c)),
1254
+ (a, True)), (x, 0, z))
1255
+ ans = I.doit()
1256
+ assert ans == Piecewise((0, b > c), (a*Min(y, z) - a*Min(0, z), True))
1257
+ for cond in (True, False):
1258
+ for yy in range(1, 3):
1259
+ for zz in range(-yy, 0, yy):
1260
+ reps = [(b > c, cond), (y, yy), (z, zz)]
1261
+ assert ans.subs(reps) == I.subs(reps).doit()
1262
+
1263
+
1264
+ def test_unevaluated_integrals():
1265
+ f = Function('f')
1266
+ p = Piecewise((1, Eq(f(x) - 1, 0)), (2, x - 10 < 0), (0, True))
1267
+ assert p.integrate(x) == Integral(p, x)
1268
+ assert p.integrate((x, 0, 5)) == Integral(p, (x, 0, 5))
1269
+ # test it by replacing f(x) with x%2 which will not
1270
+ # affect the answer: the integrand is essentially 2 over
1271
+ # the domain of integration
1272
+ assert Integral(p, (x, 0, 5)).subs(f(x), x%2).n() == 10.0
1273
+
1274
+ # this is a test of using _solve_inequality when
1275
+ # solve_univariate_inequality fails
1276
+ assert p.integrate(y) == Piecewise(
1277
+ (y, Eq(f(x), 1) | ((x < 10) & Eq(f(x), 1))),
1278
+ (2*y, (x > -oo) & (x < 10)), (0, True))
1279
+
1280
+
1281
+ def test_conditions_as_alternate_booleans():
1282
+ a, b, c = symbols('a:c')
1283
+ assert Piecewise((x, Piecewise((y < 1, x > 0), (y > 1, True)))
1284
+ ) == Piecewise((x, ITE(x > 0, y < 1, y > 1)))
1285
+
1286
+
1287
+ def test_Piecewise_rewrite_as_ITE():
1288
+ a, b, c, d = symbols('a:d')
1289
+
1290
+ def _ITE(*args):
1291
+ return Piecewise(*args).rewrite(ITE)
1292
+
1293
+ assert _ITE((a, x < 1), (b, x >= 1)) == ITE(x < 1, a, b)
1294
+ assert _ITE((a, x < 1), (b, x < oo)) == ITE(x < 1, a, b)
1295
+ assert _ITE((a, x < 1), (b, Or(y < 1, x < oo)), (c, y > 0)
1296
+ ) == ITE(x < 1, a, b)
1297
+ assert _ITE((a, x < 1), (b, True)) == ITE(x < 1, a, b)
1298
+ assert _ITE((a, x < 1), (b, x < 2), (c, True)
1299
+ ) == ITE(x < 1, a, ITE(x < 2, b, c))
1300
+ assert _ITE((a, x < 1), (b, y < 2), (c, True)
1301
+ ) == ITE(x < 1, a, ITE(y < 2, b, c))
1302
+ assert _ITE((a, x < 1), (b, x < oo), (c, y < 1)
1303
+ ) == ITE(x < 1, a, b)
1304
+ assert _ITE((a, x < 1), (c, y < 1), (b, x < oo), (d, True)
1305
+ ) == ITE(x < 1, a, ITE(y < 1, c, b))
1306
+ assert _ITE((a, x < 0), (b, Or(x < oo, y < 1))
1307
+ ) == ITE(x < 0, a, b)
1308
+ raises(TypeError, lambda: _ITE((x + 1, x < 1), (x, True)))
1309
+ # if `a` in the following were replaced with y then the coverage
1310
+ # is complete but something other than as_set would need to be
1311
+ # used to detect this
1312
+ raises(NotImplementedError, lambda: _ITE((x, x < y), (y, x >= a)))
1313
+ raises(ValueError, lambda: _ITE((a, x < 2), (b, x > 3)))
1314
+
1315
+
1316
+ def test_issue_14052():
1317
+ assert integrate(abs(sin(x)), (x, 0, 2*pi)) == 4
1318
+
1319
+
1320
+ def test_issue_14240():
1321
+ assert piecewise_fold(
1322
+ Piecewise((1, a), (2, b), (4, True)) +
1323
+ Piecewise((8, a), (16, True))
1324
+ ) == Piecewise((9, a), (18, b), (20, True))
1325
+ assert piecewise_fold(
1326
+ Piecewise((2, a), (3, b), (5, True)) *
1327
+ Piecewise((7, a), (11, True))
1328
+ ) == Piecewise((14, a), (33, b), (55, True))
1329
+ # these will hang if naive folding is used
1330
+ assert piecewise_fold(Add(*[
1331
+ Piecewise((i, a), (0, True)) for i in range(40)])
1332
+ ) == Piecewise((780, a), (0, True))
1333
+ assert piecewise_fold(Mul(*[
1334
+ Piecewise((i, a), (0, True)) for i in range(1, 41)])
1335
+ ) == Piecewise((factorial(40), a), (0, True))
1336
+
1337
+
1338
+ def test_issue_14787():
1339
+ x = Symbol('x')
1340
+ f = Piecewise((x, x < 1), ((S(58) / 7), True))
1341
+ assert str(f.evalf()) == "Piecewise((x, x < 1), (8.28571428571429, True))"
1342
+
1343
+ def test_issue_21481():
1344
+ b, e = symbols('b e')
1345
+ C = Piecewise(
1346
+ (2,
1347
+ ((b > 1) & (e > 0)) |
1348
+ ((b > 0) & (b < 1) & (e < 0)) |
1349
+ ((e >= 2) & (b < -1) & Eq(Mod(e, 2), 0)) |
1350
+ ((e <= -2) & (b > -1) & (b < 0) & Eq(Mod(e, 2), 0))),
1351
+ (S.Half,
1352
+ ((b > 1) & (e < 0)) |
1353
+ ((b > 0) & (e > 0) & (b < 1)) |
1354
+ ((e <= -2) & (b < -1) & Eq(Mod(e, 2), 0)) |
1355
+ ((e >= 2) & (b > -1) & (b < 0) & Eq(Mod(e, 2), 0))),
1356
+ (-S.Half,
1357
+ Eq(Mod(e, 2), 1) &
1358
+ (((e <= -1) & (b < -1)) | ((e >= 1) & (b > -1) & (b < 0)))),
1359
+ (-2,
1360
+ ((e >= 1) & (b < -1) & Eq(Mod(e, 2), 1)) |
1361
+ ((e <= -1) & (b > -1) & (b < 0) & Eq(Mod(e, 2), 1)))
1362
+ )
1363
+ A = Piecewise(
1364
+ (1, Eq(b, 1) | Eq(e, 0) | (Eq(b, -1) & Eq(Mod(e, 2), 0))),
1365
+ (0, Eq(b, 0) & (e > 0)),
1366
+ (-1, Eq(b, -1) & Eq(Mod(e, 2), 1)),
1367
+ (C, Eq(im(b), 0) & Eq(im(e), 0))
1368
+ )
1369
+
1370
+ B = piecewise_fold(A)
1371
+ sa = A.simplify()
1372
+ sb = B.simplify()
1373
+ v = (-2, -1, -S.Half, 0, S.Half, 1, 2)
1374
+ for i in v:
1375
+ for j in v:
1376
+ r = {b:i, e:j}
1377
+ ok = [k.xreplace(r) for k in (A, B, sa, sb)]
1378
+ assert len(set(ok)) == 1
1379
+
1380
+
1381
+ def test_issue_8458():
1382
+ x, y = symbols('x y')
1383
+ # Original issue
1384
+ p1 = Piecewise((0, Eq(x, 0)), (sin(x), True))
1385
+ assert p1.simplify() == sin(x)
1386
+ # Slightly larger variant
1387
+ p2 = Piecewise((x, Eq(x, 0)), (4*x + (y-2)**4, Eq(x, 0) & Eq(x+y, 2)), (sin(x), True))
1388
+ assert p2.simplify() == sin(x)
1389
+ # Test for problem highlighted during review
1390
+ p3 = Piecewise((x+1, Eq(x, -1)), (4*x + (y-2)**4, Eq(x, 0) & Eq(x+y, 2)), (sin(x), True))
1391
+ assert p3.simplify() == Piecewise((0, Eq(x, -1)), (sin(x), True))
1392
+
1393
+
1394
+ def test_issue_16417():
1395
+ z = Symbol('z')
1396
+ assert unchanged(Piecewise, (1, Or(Eq(im(z), 0), Gt(re(z), 0))), (2, True))
1397
+
1398
+ x = Symbol('x')
1399
+ assert unchanged(Piecewise, (S.Pi, re(x) < 0),
1400
+ (0, Or(re(x) > 0, Ne(im(x), 0))),
1401
+ (S.NaN, True))
1402
+ r = Symbol('r', real=True)
1403
+ p = Piecewise((S.Pi, re(r) < 0),
1404
+ (0, Or(re(r) > 0, Ne(im(r), 0))),
1405
+ (S.NaN, True))
1406
+ assert p == Piecewise((S.Pi, r < 0),
1407
+ (0, r > 0),
1408
+ (S.NaN, True), evaluate=False)
1409
+ # Does not work since imaginary != 0...
1410
+ #i = Symbol('i', imaginary=True)
1411
+ #p = Piecewise((S.Pi, re(i) < 0),
1412
+ # (0, Or(re(i) > 0, Ne(im(i), 0))),
1413
+ # (S.NaN, True))
1414
+ #assert p == Piecewise((0, Ne(im(i), 0)),
1415
+ # (S.NaN, True), evaluate=False)
1416
+ i = I*r
1417
+ p = Piecewise((S.Pi, re(i) < 0),
1418
+ (0, Or(re(i) > 0, Ne(im(i), 0))),
1419
+ (S.NaN, True))
1420
+ assert p == Piecewise((0, Ne(im(i), 0)),
1421
+ (S.NaN, True), evaluate=False)
1422
+ assert p == Piecewise((0, Ne(r, 0)),
1423
+ (S.NaN, True), evaluate=False)
1424
+
1425
+
1426
+ def test_eval_rewrite_as_KroneckerDelta():
1427
+ x, y, z, n, t, m = symbols('x y z n t m')
1428
+ K = KroneckerDelta
1429
+ f = lambda p: expand(p.rewrite(K))
1430
+
1431
+ p1 = Piecewise((0, Eq(x, y)), (1, True))
1432
+ assert f(p1) == 1 - K(x, y)
1433
+
1434
+ p2 = Piecewise((x, Eq(y,0)), (z, Eq(t,0)), (n, True))
1435
+ assert f(p2) == n*K(0, t)*K(0, y) - n*K(0, t) - n*K(0, y) + n + \
1436
+ x*K(0, y) - z*K(0, t)*K(0, y) + z*K(0, t)
1437
+
1438
+ p3 = Piecewise((1, Ne(x, y)), (0, True))
1439
+ assert f(p3) == 1 - K(x, y)
1440
+
1441
+ p4 = Piecewise((1, Eq(x, 3)), (4, True), (5, True))
1442
+ assert f(p4) == 4 - 3*K(3, x)
1443
+
1444
+ p5 = Piecewise((3, Ne(x, 2)), (4, Eq(y, 2)), (5, True))
1445
+ assert f(p5) == -K(2, x)*K(2, y) + 2*K(2, x) + 3
1446
+
1447
+ p6 = Piecewise((0, Ne(x, 1) & Ne(y, 4)), (1, True))
1448
+ assert f(p6) == -K(1, x)*K(4, y) + K(1, x) + K(4, y)
1449
+
1450
+ p7 = Piecewise((2, Eq(y, 3) & Ne(x, 2)), (1, True))
1451
+ assert f(p7) == -K(2, x)*K(3, y) + K(3, y) + 1
1452
+
1453
+ p8 = Piecewise((4, Eq(x, 3) & Ne(y, 2)), (1, True))
1454
+ assert f(p8) == -3*K(2, y)*K(3, x) + 3*K(3, x) + 1
1455
+
1456
+ p9 = Piecewise((6, Eq(x, 4) & Eq(y, 1)), (1, True))
1457
+ assert f(p9) == 5 * K(1, y) * K(4, x) + 1
1458
+
1459
+ p10 = Piecewise((4, Ne(x, -4) | Ne(y, 1)), (1, True))
1460
+ assert f(p10) == -3 * K(-4, x) * K(1, y) + 4
1461
+
1462
+ p11 = Piecewise((1, Eq(y, 2) | Ne(x, -3)), (2, True))
1463
+ assert f(p11) == -K(-3, x)*K(2, y) + K(-3, x) + 1
1464
+
1465
+ p12 = Piecewise((-1, Eq(x, 1) | Ne(y, 3)), (1, True))
1466
+ assert f(p12) == -2*K(1, x)*K(3, y) + 2*K(3, y) - 1
1467
+
1468
+ p13 = Piecewise((3, Eq(x, 2) | Eq(y, 4)), (1, True))
1469
+ assert f(p13) == -2*K(2, x)*K(4, y) + 2*K(2, x) + 2*K(4, y) + 1
1470
+
1471
+ p14 = Piecewise((1, Ne(x, 0) | Ne(y, 1)), (3, True))
1472
+ assert f(p14) == 2 * K(0, x) * K(1, y) + 1
1473
+
1474
+ p15 = Piecewise((2, Eq(x, 3) | Ne(y, 2)), (3, Eq(x, 4) & Eq(y, 5)), (1, True))
1475
+ assert f(p15) == -2*K(2, y)*K(3, x)*K(4, x)*K(5, y) + K(2, y)*K(3, x) + \
1476
+ 2*K(2, y)*K(4, x)*K(5, y) - K(2, y) + 2
1477
+
1478
+ p16 = Piecewise((0, Ne(m, n)), (1, True))*Piecewise((0, Ne(n, t)), (1, True))\
1479
+ *Piecewise((0, Ne(n, x)), (1, True)) - Piecewise((0, Ne(t, x)), (1, True))
1480
+ assert f(p16) == K(m, n)*K(n, t)*K(n, x) - K(t, x)
1481
+
1482
+ p17 = Piecewise((0, Ne(t, x) & (Ne(m, n) | Ne(n, t) | Ne(n, x))),
1483
+ (1, Ne(t, x)), (-1, Ne(m, n) | Ne(n, t) | Ne(n, x)), (0, True))
1484
+ assert f(p17) == K(m, n)*K(n, t)*K(n, x) - K(t, x)
1485
+
1486
+ p18 = Piecewise((-4, Eq(y, 1) | (Eq(x, -5) & Eq(x, z))), (4, True))
1487
+ assert f(p18) == 8*K(-5, x)*K(1, y)*K(x, z) - 8*K(-5, x)*K(x, z) - 8*K(1, y) + 4
1488
+
1489
+ p19 = Piecewise((0, x > 2), (1, True))
1490
+ assert f(p19) == p19
1491
+
1492
+ p20 = Piecewise((0, And(x < 2, x > -5)), (1, True))
1493
+ assert f(p20) == p20
1494
+
1495
+ p21 = Piecewise((0, Or(x > 1, x < 0)), (1, True))
1496
+ assert f(p21) == p21
1497
+
1498
+ p22 = Piecewise((0, ~((Eq(y, -1) | Ne(x, 0)) & (Ne(x, 1) | Ne(y, -1)))), (1, True))
1499
+ assert f(p22) == K(-1, y)*K(0, x) - K(-1, y)*K(1, x) - K(0, x) + 1
1500
+
1501
+
1502
+ @slow
1503
+ def test_identical_conds_issue():
1504
+ from sympy.stats import Uniform, density
1505
+ u1 = Uniform('u1', 0, 1)
1506
+ u2 = Uniform('u2', 0, 1)
1507
+ # Result is quite big, so not really important here (and should ideally be
1508
+ # simpler). Should not give an exception though.
1509
+ density(u1 + u2)
1510
+
1511
+
1512
+ def test_issue_7370():
1513
+ f = Piecewise((1, x <= 2400))
1514
+ v = integrate(f, (x, 0, Float("252.4", 30)))
1515
+ assert str(v) == '252.400000000000000000000000000'
1516
+
1517
+
1518
+ def test_issue_14933():
1519
+ x = Symbol('x')
1520
+ y = Symbol('y')
1521
+
1522
+ inp = MatrixSymbol('inp', 1, 1)
1523
+ rep_dict = {y: inp[0, 0], x: inp[0, 0]}
1524
+
1525
+ p = Piecewise((1, ITE(y > 0, x < 0, True)))
1526
+ assert p.xreplace(rep_dict) == Piecewise((1, ITE(inp[0, 0] > 0, inp[0, 0] < 0, True)))
1527
+
1528
+
1529
+ def test_issue_16715():
1530
+ raises(NotImplementedError, lambda: Piecewise((x, x<0), (0, y>1)).as_expr_set_pairs())
1531
+
1532
+
1533
+ def test_issue_20360():
1534
+ t, tau = symbols("t tau", real=True)
1535
+ n = symbols("n", integer=True)
1536
+ lam = pi * (n - S.Half)
1537
+ eq = integrate(exp(lam * tau), (tau, 0, t))
1538
+ assert eq.simplify() == (2*exp(pi*t*(2*n - 1)/2) - 2)/(pi*(2*n - 1))
1539
+
1540
+
1541
+ def test_piecewise_eval():
1542
+ # XXX these tests might need modification if this
1543
+ # simplification is moved out of eval and into
1544
+ # boolalg or Piecewise simplification functions
1545
+ f = lambda x: x.args[0].cond
1546
+ # unsimplified
1547
+ assert f(Piecewise((x, (x > -oo) & (x < 3)))
1548
+ ) == ((x > -oo) & (x < 3))
1549
+ assert f(Piecewise((x, (x > -oo) & (x < oo)))
1550
+ ) == ((x > -oo) & (x < oo))
1551
+ assert f(Piecewise((x, (x > -3) & (x < 3)))
1552
+ ) == ((x > -3) & (x < 3))
1553
+ assert f(Piecewise((x, (x > -3) & (x < oo)))
1554
+ ) == ((x > -3) & (x < oo))
1555
+ assert f(Piecewise((x, (x <= 3) & (x > -oo)))
1556
+ ) == ((x <= 3) & (x > -oo))
1557
+ assert f(Piecewise((x, (x <= 3) & (x > -3)))
1558
+ ) == ((x <= 3) & (x > -3))
1559
+ assert f(Piecewise((x, (x >= -3) & (x < 3)))
1560
+ ) == ((x >= -3) & (x < 3))
1561
+ assert f(Piecewise((x, (x >= -3) & (x < oo)))
1562
+ ) == ((x >= -3) & (x < oo))
1563
+ assert f(Piecewise((x, (x >= -3) & (x <= 3)))
1564
+ ) == ((x >= -3) & (x <= 3))
1565
+ # could simplify by keeping only the first
1566
+ # arg of result
1567
+ assert f(Piecewise((x, (x <= oo) & (x > -oo)))
1568
+ ) == (x > -oo) & (x <= oo)
1569
+ assert f(Piecewise((x, (x <= oo) & (x > -3)))
1570
+ ) == (x > -3) & (x <= oo)
1571
+ assert f(Piecewise((x, (x >= -oo) & (x < 3)))
1572
+ ) == (x < 3) & (x >= -oo)
1573
+ assert f(Piecewise((x, (x >= -oo) & (x < oo)))
1574
+ ) == (x < oo) & (x >= -oo)
1575
+ assert f(Piecewise((x, (x >= -oo) & (x <= 3)))
1576
+ ) == (x <= 3) & (x >= -oo)
1577
+ assert f(Piecewise((x, (x >= -oo) & (x <= oo)))
1578
+ ) == (x <= oo) & (x >= -oo) # but cannot be True unless x is real
1579
+ assert f(Piecewise((x, (x >= -3) & (x <= oo)))
1580
+ ) == (x >= -3) & (x <= oo)
1581
+ assert f(Piecewise((x, (Abs(arg(a)) <= 1) | (Abs(arg(a)) < 1)))
1582
+ ) == (Abs(arg(a)) <= 1) | (Abs(arg(a)) < 1)
1583
+
1584
+
1585
+ def test_issue_22533():
1586
+ x = Symbol('x', real=True)
1587
+ f = Piecewise((-1 / x, x <= 0), (1 / x, True))
1588
+ assert integrate(f, x) == Piecewise((-log(x), x <= 0), (log(x), True))
1589
+
1590
+
1591
+ def test_issue_24072():
1592
+ assert Piecewise((1, x > 1), (2, x <= 1), (3, x <= 1)
1593
+ ) == Piecewise((1, x > 1), (2, True))
1594
+
1595
+
1596
+ def test_piecewise__eval_is_meromorphic():
1597
+ """ Issue 24127: Tests eval_is_meromorphic auxiliary method """
1598
+ x = symbols('x', real=True)
1599
+ f = Piecewise((1, x < 0), (sqrt(1 - x), True))
1600
+ assert f.is_meromorphic(x, I) is None
1601
+ assert f.is_meromorphic(x, -1) == True
1602
+ assert f.is_meromorphic(x, 0) == None
1603
+ assert f.is_meromorphic(x, 1) == False
1604
+ assert f.is_meromorphic(x, 2) == True
1605
+ assert f.is_meromorphic(x, Symbol('a')) == None
1606
+ assert f.is_meromorphic(x, Symbol('a', real=True)) == None
venv/lib/python3.10/site-packages/sympy/functions/elementary/tests/test_trigonometric.py ADDED
@@ -0,0 +1,2162 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ from sympy.calculus.accumulationbounds import AccumBounds
2
+ from sympy.core.add import Add
3
+ from sympy.core.function import (Lambda, diff)
4
+ from sympy.core.mod import Mod
5
+ from sympy.core.mul import Mul
6
+ from sympy.core.numbers import (E, Float, I, Rational, nan, oo, pi, zoo)
7
+ from sympy.core.power import Pow
8
+ from sympy.core.singleton import S
9
+ from sympy.core.symbol import (Symbol, symbols)
10
+ from sympy.functions.elementary.complexes import (arg, conjugate, im, re)
11
+ from sympy.functions.elementary.exponential import (exp, log)
12
+ from sympy.functions.elementary.hyperbolic import (acoth, asinh, atanh, cosh, coth, sinh, tanh)
13
+ from sympy.functions.elementary.miscellaneous import sqrt
14
+ from sympy.functions.elementary.trigonometric import (acos, acot, acsc, asec, asin, atan, atan2,
15
+ cos, cot, csc, sec, sin, sinc, tan)
16
+ from sympy.functions.special.bessel import (besselj, jn)
17
+ from sympy.functions.special.delta_functions import Heaviside
18
+ from sympy.matrices.dense import Matrix
19
+ from sympy.polys.polytools import (cancel, gcd)
20
+ from sympy.series.limits import limit
21
+ from sympy.series.order import O
22
+ from sympy.series.series import series
23
+ from sympy.sets.fancysets import ImageSet
24
+ from sympy.sets.sets import (FiniteSet, Interval)
25
+ from sympy.simplify.simplify import simplify
26
+ from sympy.core.expr import unchanged
27
+ from sympy.core.function import ArgumentIndexError
28
+ from sympy.core.relational import Ne, Eq
29
+ from sympy.functions.elementary.piecewise import Piecewise
30
+ from sympy.sets.setexpr import SetExpr
31
+ from sympy.testing.pytest import XFAIL, slow, raises
32
+
33
+
34
+ x, y, z = symbols('x y z')
35
+ r = Symbol('r', real=True)
36
+ k, m = symbols('k m', integer=True)
37
+ p = Symbol('p', positive=True)
38
+ n = Symbol('n', negative=True)
39
+ np = Symbol('p', nonpositive=True)
40
+ nn = Symbol('n', nonnegative=True)
41
+ nz = Symbol('nz', nonzero=True)
42
+ ep = Symbol('ep', extended_positive=True)
43
+ en = Symbol('en', extended_negative=True)
44
+ enp = Symbol('ep', extended_nonpositive=True)
45
+ enn = Symbol('en', extended_nonnegative=True)
46
+ enz = Symbol('enz', extended_nonzero=True)
47
+ a = Symbol('a', algebraic=True)
48
+ na = Symbol('na', nonzero=True, algebraic=True)
49
+
50
+
51
+ def test_sin():
52
+ x, y = symbols('x y')
53
+ z = symbols('z', imaginary=True)
54
+
55
+ assert sin.nargs == FiniteSet(1)
56
+ assert sin(nan) is nan
57
+ assert sin(zoo) is nan
58
+
59
+ assert sin(oo) == AccumBounds(-1, 1)
60
+ assert sin(oo) - sin(oo) == AccumBounds(-2, 2)
61
+ assert sin(oo*I) == oo*I
62
+ assert sin(-oo*I) == -oo*I
63
+ assert 0*sin(oo) is S.Zero
64
+ assert 0/sin(oo) is S.Zero
65
+ assert 0 + sin(oo) == AccumBounds(-1, 1)
66
+ assert 5 + sin(oo) == AccumBounds(4, 6)
67
+
68
+ assert sin(0) == 0
69
+
70
+ assert sin(z*I) == I*sinh(z)
71
+ assert sin(asin(x)) == x
72
+ assert sin(atan(x)) == x / sqrt(1 + x**2)
73
+ assert sin(acos(x)) == sqrt(1 - x**2)
74
+ assert sin(acot(x)) == 1 / (sqrt(1 + 1 / x**2) * x)
75
+ assert sin(acsc(x)) == 1 / x
76
+ assert sin(asec(x)) == sqrt(1 - 1 / x**2)
77
+ assert sin(atan2(y, x)) == y / sqrt(x**2 + y**2)
78
+
79
+ assert sin(pi*I) == sinh(pi)*I
80
+ assert sin(-pi*I) == -sinh(pi)*I
81
+ assert sin(-2*I) == -sinh(2)*I
82
+
83
+ assert sin(pi) == 0
84
+ assert sin(-pi) == 0
85
+ assert sin(2*pi) == 0
86
+ assert sin(-2*pi) == 0
87
+ assert sin(-3*10**73*pi) == 0
88
+ assert sin(7*10**103*pi) == 0
89
+
90
+ assert sin(pi/2) == 1
91
+ assert sin(-pi/2) == -1
92
+ assert sin(pi*Rational(5, 2)) == 1
93
+ assert sin(pi*Rational(7, 2)) == -1
94
+
95
+ ne = symbols('ne', integer=True, even=False)
96
+ e = symbols('e', even=True)
97
+ assert sin(pi*ne/2) == (-1)**(ne/2 - S.Half)
98
+ assert sin(pi*k/2).func == sin
99
+ assert sin(pi*e/2) == 0
100
+ assert sin(pi*k) == 0
101
+ assert sin(pi*k).subs(k, 3) == sin(pi*k/2).subs(k, 6) # issue 8298
102
+
103
+ assert sin(pi/3) == S.Half*sqrt(3)
104
+ assert sin(pi*Rational(-2, 3)) == Rational(-1, 2)*sqrt(3)
105
+
106
+ assert sin(pi/4) == S.Half*sqrt(2)
107
+ assert sin(-pi/4) == Rational(-1, 2)*sqrt(2)
108
+ assert sin(pi*Rational(17, 4)) == S.Half*sqrt(2)
109
+ assert sin(pi*Rational(-3, 4)) == Rational(-1, 2)*sqrt(2)
110
+
111
+ assert sin(pi/6) == S.Half
112
+ assert sin(-pi/6) == Rational(-1, 2)
113
+ assert sin(pi*Rational(7, 6)) == Rational(-1, 2)
114
+ assert sin(pi*Rational(-5, 6)) == Rational(-1, 2)
115
+
116
+ assert sin(pi*Rational(1, 5)) == sqrt((5 - sqrt(5)) / 8)
117
+ assert sin(pi*Rational(2, 5)) == sqrt((5 + sqrt(5)) / 8)
118
+ assert sin(pi*Rational(3, 5)) == sin(pi*Rational(2, 5))
119
+ assert sin(pi*Rational(4, 5)) == sin(pi*Rational(1, 5))
120
+ assert sin(pi*Rational(6, 5)) == -sin(pi*Rational(1, 5))
121
+ assert sin(pi*Rational(8, 5)) == -sin(pi*Rational(2, 5))
122
+
123
+ assert sin(pi*Rational(-1273, 5)) == -sin(pi*Rational(2, 5))
124
+
125
+ assert sin(pi/8) == sqrt((2 - sqrt(2))/4)
126
+
127
+ assert sin(pi/10) == Rational(-1, 4) + sqrt(5)/4
128
+
129
+ assert sin(pi/12) == -sqrt(2)/4 + sqrt(6)/4
130
+ assert sin(pi*Rational(5, 12)) == sqrt(2)/4 + sqrt(6)/4
131
+ assert sin(pi*Rational(-7, 12)) == -sqrt(2)/4 - sqrt(6)/4
132
+ assert sin(pi*Rational(-11, 12)) == sqrt(2)/4 - sqrt(6)/4
133
+
134
+ assert sin(pi*Rational(104, 105)) == sin(pi/105)
135
+ assert sin(pi*Rational(106, 105)) == -sin(pi/105)
136
+
137
+ assert sin(pi*Rational(-104, 105)) == -sin(pi/105)
138
+ assert sin(pi*Rational(-106, 105)) == sin(pi/105)
139
+
140
+ assert sin(x*I) == sinh(x)*I
141
+
142
+ assert sin(k*pi) == 0
143
+ assert sin(17*k*pi) == 0
144
+ assert sin(2*k*pi + 4) == sin(4)
145
+ assert sin(2*k*pi + m*pi + 1) == (-1)**(m + 2*k)*sin(1)
146
+
147
+ assert sin(k*pi*I) == sinh(k*pi)*I
148
+
149
+ assert sin(r).is_real is True
150
+
151
+ assert sin(0, evaluate=False).is_algebraic
152
+ assert sin(a).is_algebraic is None
153
+ assert sin(na).is_algebraic is False
154
+ q = Symbol('q', rational=True)
155
+ assert sin(pi*q).is_algebraic
156
+ qn = Symbol('qn', rational=True, nonzero=True)
157
+ assert sin(qn).is_rational is False
158
+ assert sin(q).is_rational is None # issue 8653
159
+
160
+ assert isinstance(sin( re(x) - im(y)), sin) is True
161
+ assert isinstance(sin(-re(x) + im(y)), sin) is False
162
+
163
+ assert sin(SetExpr(Interval(0, 1))) == SetExpr(ImageSet(Lambda(x, sin(x)),
164
+ Interval(0, 1)))
165
+
166
+ for d in list(range(1, 22)) + [60, 85]:
167
+ for n in range(d*2 + 1):
168
+ x = n*pi/d
169
+ e = abs( float(sin(x)) - sin(float(x)) )
170
+ assert e < 1e-12
171
+
172
+ assert sin(0, evaluate=False).is_zero is True
173
+ assert sin(k*pi, evaluate=False).is_zero is True
174
+
175
+ assert sin(Add(1, -1, evaluate=False), evaluate=False).is_zero is True
176
+
177
+
178
+ def test_sin_cos():
179
+ for d in [1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 24, 30, 40, 60, 120]: # list is not exhaustive...
180
+ for n in range(-2*d, d*2):
181
+ x = n*pi/d
182
+ assert sin(x + pi/2) == cos(x), "fails for %d*pi/%d" % (n, d)
183
+ assert sin(x - pi/2) == -cos(x), "fails for %d*pi/%d" % (n, d)
184
+ assert sin(x) == cos(x - pi/2), "fails for %d*pi/%d" % (n, d)
185
+ assert -sin(x) == cos(x + pi/2), "fails for %d*pi/%d" % (n, d)
186
+
187
+
188
+ def test_sin_series():
189
+ assert sin(x).series(x, 0, 9) == \
190
+ x - x**3/6 + x**5/120 - x**7/5040 + O(x**9)
191
+
192
+
193
+ def test_sin_rewrite():
194
+ assert sin(x).rewrite(exp) == -I*(exp(I*x) - exp(-I*x))/2
195
+ assert sin(x).rewrite(tan) == 2*tan(x/2)/(1 + tan(x/2)**2)
196
+ assert sin(x).rewrite(cot) == \
197
+ Piecewise((0, Eq(im(x), 0) & Eq(Mod(x, pi), 0)),
198
+ (2*cot(x/2)/(cot(x/2)**2 + 1), True))
199
+ assert sin(sinh(x)).rewrite(
200
+ exp).subs(x, 3).n() == sin(x).rewrite(exp).subs(x, sinh(3)).n()
201
+ assert sin(cosh(x)).rewrite(
202
+ exp).subs(x, 3).n() == sin(x).rewrite(exp).subs(x, cosh(3)).n()
203
+ assert sin(tanh(x)).rewrite(
204
+ exp).subs(x, 3).n() == sin(x).rewrite(exp).subs(x, tanh(3)).n()
205
+ assert sin(coth(x)).rewrite(
206
+ exp).subs(x, 3).n() == sin(x).rewrite(exp).subs(x, coth(3)).n()
207
+ assert sin(sin(x)).rewrite(
208
+ exp).subs(x, 3).n() == sin(x).rewrite(exp).subs(x, sin(3)).n()
209
+ assert sin(cos(x)).rewrite(
210
+ exp).subs(x, 3).n() == sin(x).rewrite(exp).subs(x, cos(3)).n()
211
+ assert sin(tan(x)).rewrite(
212
+ exp).subs(x, 3).n() == sin(x).rewrite(exp).subs(x, tan(3)).n()
213
+ assert sin(cot(x)).rewrite(
214
+ exp).subs(x, 3).n() == sin(x).rewrite(exp).subs(x, cot(3)).n()
215
+ assert sin(log(x)).rewrite(Pow) == I*x**-I / 2 - I*x**I /2
216
+ assert sin(x).rewrite(csc) == 1/csc(x)
217
+ assert sin(x).rewrite(cos) == cos(x - pi / 2, evaluate=False)
218
+ assert sin(x).rewrite(sec) == 1 / sec(x - pi / 2, evaluate=False)
219
+ assert sin(cos(x)).rewrite(Pow) == sin(cos(x))
220
+
221
+
222
+ def _test_extrig(f, i, e):
223
+ from sympy.core.function import expand_trig
224
+ assert unchanged(f, i)
225
+ assert expand_trig(f(i)) == f(i)
226
+ # testing directly instead of with .expand(trig=True)
227
+ # because the other expansions undo the unevaluated Mul
228
+ assert expand_trig(f(Mul(i, 1, evaluate=False))) == e
229
+ assert abs(f(i) - e).n() < 1e-10
230
+
231
+
232
+ def test_sin_expansion():
233
+ # Note: these formulas are not unique. The ones here come from the
234
+ # Chebyshev formulas.
235
+ assert sin(x + y).expand(trig=True) == sin(x)*cos(y) + cos(x)*sin(y)
236
+ assert sin(x - y).expand(trig=True) == sin(x)*cos(y) - cos(x)*sin(y)
237
+ assert sin(y - x).expand(trig=True) == cos(x)*sin(y) - sin(x)*cos(y)
238
+ assert sin(2*x).expand(trig=True) == 2*sin(x)*cos(x)
239
+ assert sin(3*x).expand(trig=True) == -4*sin(x)**3 + 3*sin(x)
240
+ assert sin(4*x).expand(trig=True) == -8*sin(x)**3*cos(x) + 4*sin(x)*cos(x)
241
+ _test_extrig(sin, 2, 2*sin(1)*cos(1))
242
+ _test_extrig(sin, 3, -4*sin(1)**3 + 3*sin(1))
243
+
244
+
245
+ def test_sin_AccumBounds():
246
+ assert sin(AccumBounds(-oo, oo)) == AccumBounds(-1, 1)
247
+ assert sin(AccumBounds(0, oo)) == AccumBounds(-1, 1)
248
+ assert sin(AccumBounds(-oo, 0)) == AccumBounds(-1, 1)
249
+ assert sin(AccumBounds(0, 2*S.Pi)) == AccumBounds(-1, 1)
250
+ assert sin(AccumBounds(0, S.Pi*Rational(3, 4))) == AccumBounds(0, 1)
251
+ assert sin(AccumBounds(S.Pi*Rational(3, 4), S.Pi*Rational(7, 4))) == AccumBounds(-1, sin(S.Pi*Rational(3, 4)))
252
+ assert sin(AccumBounds(S.Pi/4, S.Pi/3)) == AccumBounds(sin(S.Pi/4), sin(S.Pi/3))
253
+ assert sin(AccumBounds(S.Pi*Rational(3, 4), S.Pi*Rational(5, 6))) == AccumBounds(sin(S.Pi*Rational(5, 6)), sin(S.Pi*Rational(3, 4)))
254
+
255
+
256
+ def test_sin_fdiff():
257
+ assert sin(x).fdiff() == cos(x)
258
+ raises(ArgumentIndexError, lambda: sin(x).fdiff(2))
259
+
260
+
261
+ def test_trig_symmetry():
262
+ assert sin(-x) == -sin(x)
263
+ assert cos(-x) == cos(x)
264
+ assert tan(-x) == -tan(x)
265
+ assert cot(-x) == -cot(x)
266
+ assert sin(x + pi) == -sin(x)
267
+ assert sin(x + 2*pi) == sin(x)
268
+ assert sin(x + 3*pi) == -sin(x)
269
+ assert sin(x + 4*pi) == sin(x)
270
+ assert sin(x - 5*pi) == -sin(x)
271
+ assert cos(x + pi) == -cos(x)
272
+ assert cos(x + 2*pi) == cos(x)
273
+ assert cos(x + 3*pi) == -cos(x)
274
+ assert cos(x + 4*pi) == cos(x)
275
+ assert cos(x - 5*pi) == -cos(x)
276
+ assert tan(x + pi) == tan(x)
277
+ assert tan(x - 3*pi) == tan(x)
278
+ assert cot(x + pi) == cot(x)
279
+ assert cot(x - 3*pi) == cot(x)
280
+ assert sin(pi/2 - x) == cos(x)
281
+ assert sin(pi*Rational(3, 2) - x) == -cos(x)
282
+ assert sin(pi*Rational(5, 2) - x) == cos(x)
283
+ assert cos(pi/2 - x) == sin(x)
284
+ assert cos(pi*Rational(3, 2) - x) == -sin(x)
285
+ assert cos(pi*Rational(5, 2) - x) == sin(x)
286
+ assert tan(pi/2 - x) == cot(x)
287
+ assert tan(pi*Rational(3, 2) - x) == cot(x)
288
+ assert tan(pi*Rational(5, 2) - x) == cot(x)
289
+ assert cot(pi/2 - x) == tan(x)
290
+ assert cot(pi*Rational(3, 2) - x) == tan(x)
291
+ assert cot(pi*Rational(5, 2) - x) == tan(x)
292
+ assert sin(pi/2 + x) == cos(x)
293
+ assert cos(pi/2 + x) == -sin(x)
294
+ assert tan(pi/2 + x) == -cot(x)
295
+ assert cot(pi/2 + x) == -tan(x)
296
+
297
+
298
+ def test_cos():
299
+ x, y = symbols('x y')
300
+
301
+ assert cos.nargs == FiniteSet(1)
302
+ assert cos(nan) is nan
303
+
304
+ assert cos(oo) == AccumBounds(-1, 1)
305
+ assert cos(oo) - cos(oo) == AccumBounds(-2, 2)
306
+ assert cos(oo*I) is oo
307
+ assert cos(-oo*I) is oo
308
+ assert cos(zoo) is nan
309
+
310
+ assert cos(0) == 1
311
+
312
+ assert cos(acos(x)) == x
313
+ assert cos(atan(x)) == 1 / sqrt(1 + x**2)
314
+ assert cos(asin(x)) == sqrt(1 - x**2)
315
+ assert cos(acot(x)) == 1 / sqrt(1 + 1 / x**2)
316
+ assert cos(acsc(x)) == sqrt(1 - 1 / x**2)
317
+ assert cos(asec(x)) == 1 / x
318
+ assert cos(atan2(y, x)) == x / sqrt(x**2 + y**2)
319
+
320
+ assert cos(pi*I) == cosh(pi)
321
+ assert cos(-pi*I) == cosh(pi)
322
+ assert cos(-2*I) == cosh(2)
323
+
324
+ assert cos(pi/2) == 0
325
+ assert cos(-pi/2) == 0
326
+ assert cos(pi/2) == 0
327
+ assert cos(-pi/2) == 0
328
+ assert cos((-3*10**73 + 1)*pi/2) == 0
329
+ assert cos((7*10**103 + 1)*pi/2) == 0
330
+
331
+ n = symbols('n', integer=True, even=False)
332
+ e = symbols('e', even=True)
333
+ assert cos(pi*n/2) == 0
334
+ assert cos(pi*e/2) == (-1)**(e/2)
335
+
336
+ assert cos(pi) == -1
337
+ assert cos(-pi) == -1
338
+ assert cos(2*pi) == 1
339
+ assert cos(5*pi) == -1
340
+ assert cos(8*pi) == 1
341
+
342
+ assert cos(pi/3) == S.Half
343
+ assert cos(pi*Rational(-2, 3)) == Rational(-1, 2)
344
+
345
+ assert cos(pi/4) == S.Half*sqrt(2)
346
+ assert cos(-pi/4) == S.Half*sqrt(2)
347
+ assert cos(pi*Rational(11, 4)) == Rational(-1, 2)*sqrt(2)
348
+ assert cos(pi*Rational(-3, 4)) == Rational(-1, 2)*sqrt(2)
349
+
350
+ assert cos(pi/6) == S.Half*sqrt(3)
351
+ assert cos(-pi/6) == S.Half*sqrt(3)
352
+ assert cos(pi*Rational(7, 6)) == Rational(-1, 2)*sqrt(3)
353
+ assert cos(pi*Rational(-5, 6)) == Rational(-1, 2)*sqrt(3)
354
+
355
+ assert cos(pi*Rational(1, 5)) == (sqrt(5) + 1)/4
356
+ assert cos(pi*Rational(2, 5)) == (sqrt(5) - 1)/4
357
+ assert cos(pi*Rational(3, 5)) == -cos(pi*Rational(2, 5))
358
+ assert cos(pi*Rational(4, 5)) == -cos(pi*Rational(1, 5))
359
+ assert cos(pi*Rational(6, 5)) == -cos(pi*Rational(1, 5))
360
+ assert cos(pi*Rational(8, 5)) == cos(pi*Rational(2, 5))
361
+
362
+ assert cos(pi*Rational(-1273, 5)) == -cos(pi*Rational(2, 5))
363
+
364
+ assert cos(pi/8) == sqrt((2 + sqrt(2))/4)
365
+
366
+ assert cos(pi/12) == sqrt(2)/4 + sqrt(6)/4
367
+ assert cos(pi*Rational(5, 12)) == -sqrt(2)/4 + sqrt(6)/4
368
+ assert cos(pi*Rational(7, 12)) == sqrt(2)/4 - sqrt(6)/4
369
+ assert cos(pi*Rational(11, 12)) == -sqrt(2)/4 - sqrt(6)/4
370
+
371
+ assert cos(pi*Rational(104, 105)) == -cos(pi/105)
372
+ assert cos(pi*Rational(106, 105)) == -cos(pi/105)
373
+
374
+ assert cos(pi*Rational(-104, 105)) == -cos(pi/105)
375
+ assert cos(pi*Rational(-106, 105)) == -cos(pi/105)
376
+
377
+ assert cos(x*I) == cosh(x)
378
+ assert cos(k*pi*I) == cosh(k*pi)
379
+
380
+ assert cos(r).is_real is True
381
+
382
+ assert cos(0, evaluate=False).is_algebraic
383
+ assert cos(a).is_algebraic is None
384
+ assert cos(na).is_algebraic is False
385
+ q = Symbol('q', rational=True)
386
+ assert cos(pi*q).is_algebraic
387
+ assert cos(pi*Rational(2, 7)).is_algebraic
388
+
389
+ assert cos(k*pi) == (-1)**k
390
+ assert cos(2*k*pi) == 1
391
+ assert cos(0, evaluate=False).is_zero is False
392
+ assert cos(Rational(1, 2)).is_zero is False
393
+ # The following test will return None as the result, but really it should
394
+ # be True even if it is not always possible to resolve an assumptions query.
395
+ assert cos(asin(-1, evaluate=False), evaluate=False).is_zero is None
396
+ for d in list(range(1, 22)) + [60, 85]:
397
+ for n in range(2*d + 1):
398
+ x = n*pi/d
399
+ e = abs( float(cos(x)) - cos(float(x)) )
400
+ assert e < 1e-12
401
+
402
+
403
+ def test_issue_6190():
404
+ c = Float('123456789012345678901234567890.25', '')
405
+ for cls in [sin, cos, tan, cot]:
406
+ assert cls(c*pi) == cls(pi/4)
407
+ assert cls(4.125*pi) == cls(pi/8)
408
+ assert cls(4.7*pi) == cls((4.7 % 2)*pi)
409
+
410
+
411
+ def test_cos_series():
412
+ assert cos(x).series(x, 0, 9) == \
413
+ 1 - x**2/2 + x**4/24 - x**6/720 + x**8/40320 + O(x**9)
414
+
415
+
416
+ def test_cos_rewrite():
417
+ assert cos(x).rewrite(exp) == exp(I*x)/2 + exp(-I*x)/2
418
+ assert cos(x).rewrite(tan) == (1 - tan(x/2)**2)/(1 + tan(x/2)**2)
419
+ assert cos(x).rewrite(cot) == \
420
+ Piecewise((1, Eq(im(x), 0) & Eq(Mod(x, 2*pi), 0)),
421
+ ((cot(x/2)**2 - 1)/(cot(x/2)**2 + 1), True))
422
+ assert cos(sinh(x)).rewrite(
423
+ exp).subs(x, 3).n() == cos(x).rewrite(exp).subs(x, sinh(3)).n()
424
+ assert cos(cosh(x)).rewrite(
425
+ exp).subs(x, 3).n() == cos(x).rewrite(exp).subs(x, cosh(3)).n()
426
+ assert cos(tanh(x)).rewrite(
427
+ exp).subs(x, 3).n() == cos(x).rewrite(exp).subs(x, tanh(3)).n()
428
+ assert cos(coth(x)).rewrite(
429
+ exp).subs(x, 3).n() == cos(x).rewrite(exp).subs(x, coth(3)).n()
430
+ assert cos(sin(x)).rewrite(
431
+ exp).subs(x, 3).n() == cos(x).rewrite(exp).subs(x, sin(3)).n()
432
+ assert cos(cos(x)).rewrite(
433
+ exp).subs(x, 3).n() == cos(x).rewrite(exp).subs(x, cos(3)).n()
434
+ assert cos(tan(x)).rewrite(
435
+ exp).subs(x, 3).n() == cos(x).rewrite(exp).subs(x, tan(3)).n()
436
+ assert cos(cot(x)).rewrite(
437
+ exp).subs(x, 3).n() == cos(x).rewrite(exp).subs(x, cot(3)).n()
438
+ assert cos(log(x)).rewrite(Pow) == x**I/2 + x**-I/2
439
+ assert cos(x).rewrite(sec) == 1/sec(x)
440
+ assert cos(x).rewrite(sin) == sin(x + pi/2, evaluate=False)
441
+ assert cos(x).rewrite(csc) == 1/csc(-x + pi/2, evaluate=False)
442
+ assert cos(sin(x)).rewrite(Pow) == cos(sin(x))
443
+
444
+
445
+ def test_cos_expansion():
446
+ assert cos(x + y).expand(trig=True) == cos(x)*cos(y) - sin(x)*sin(y)
447
+ assert cos(x - y).expand(trig=True) == cos(x)*cos(y) + sin(x)*sin(y)
448
+ assert cos(y - x).expand(trig=True) == cos(x)*cos(y) + sin(x)*sin(y)
449
+ assert cos(2*x).expand(trig=True) == 2*cos(x)**2 - 1
450
+ assert cos(3*x).expand(trig=True) == 4*cos(x)**3 - 3*cos(x)
451
+ assert cos(4*x).expand(trig=True) == 8*cos(x)**4 - 8*cos(x)**2 + 1
452
+ _test_extrig(cos, 2, 2*cos(1)**2 - 1)
453
+ _test_extrig(cos, 3, 4*cos(1)**3 - 3*cos(1))
454
+
455
+
456
+ def test_cos_AccumBounds():
457
+ assert cos(AccumBounds(-oo, oo)) == AccumBounds(-1, 1)
458
+ assert cos(AccumBounds(0, oo)) == AccumBounds(-1, 1)
459
+ assert cos(AccumBounds(-oo, 0)) == AccumBounds(-1, 1)
460
+ assert cos(AccumBounds(0, 2*S.Pi)) == AccumBounds(-1, 1)
461
+ assert cos(AccumBounds(-S.Pi/3, S.Pi/4)) == AccumBounds(cos(-S.Pi/3), 1)
462
+ assert cos(AccumBounds(S.Pi*Rational(3, 4), S.Pi*Rational(5, 4))) == AccumBounds(-1, cos(S.Pi*Rational(3, 4)))
463
+ assert cos(AccumBounds(S.Pi*Rational(5, 4), S.Pi*Rational(4, 3))) == AccumBounds(cos(S.Pi*Rational(5, 4)), cos(S.Pi*Rational(4, 3)))
464
+ assert cos(AccumBounds(S.Pi/4, S.Pi/3)) == AccumBounds(cos(S.Pi/3), cos(S.Pi/4))
465
+
466
+
467
+ def test_cos_fdiff():
468
+ assert cos(x).fdiff() == -sin(x)
469
+ raises(ArgumentIndexError, lambda: cos(x).fdiff(2))
470
+
471
+
472
+ def test_tan():
473
+ assert tan(nan) is nan
474
+
475
+ assert tan(zoo) is nan
476
+ assert tan(oo) == AccumBounds(-oo, oo)
477
+ assert tan(oo) - tan(oo) == AccumBounds(-oo, oo)
478
+ assert tan.nargs == FiniteSet(1)
479
+ assert tan(oo*I) == I
480
+ assert tan(-oo*I) == -I
481
+
482
+ assert tan(0) == 0
483
+
484
+ assert tan(atan(x)) == x
485
+ assert tan(asin(x)) == x / sqrt(1 - x**2)
486
+ assert tan(acos(x)) == sqrt(1 - x**2) / x
487
+ assert tan(acot(x)) == 1 / x
488
+ assert tan(acsc(x)) == 1 / (sqrt(1 - 1 / x**2) * x)
489
+ assert tan(asec(x)) == sqrt(1 - 1 / x**2) * x
490
+ assert tan(atan2(y, x)) == y/x
491
+
492
+ assert tan(pi*I) == tanh(pi)*I
493
+ assert tan(-pi*I) == -tanh(pi)*I
494
+ assert tan(-2*I) == -tanh(2)*I
495
+
496
+ assert tan(pi) == 0
497
+ assert tan(-pi) == 0
498
+ assert tan(2*pi) == 0
499
+ assert tan(-2*pi) == 0
500
+ assert tan(-3*10**73*pi) == 0
501
+
502
+ assert tan(pi/2) is zoo
503
+ assert tan(pi*Rational(3, 2)) is zoo
504
+
505
+ assert tan(pi/3) == sqrt(3)
506
+ assert tan(pi*Rational(-2, 3)) == sqrt(3)
507
+
508
+ assert tan(pi/4) is S.One
509
+ assert tan(-pi/4) is S.NegativeOne
510
+ assert tan(pi*Rational(17, 4)) is S.One
511
+ assert tan(pi*Rational(-3, 4)) is S.One
512
+
513
+ assert tan(pi/5) == sqrt(5 - 2*sqrt(5))
514
+ assert tan(pi*Rational(2, 5)) == sqrt(5 + 2*sqrt(5))
515
+ assert tan(pi*Rational(18, 5)) == -sqrt(5 + 2*sqrt(5))
516
+ assert tan(pi*Rational(-16, 5)) == -sqrt(5 - 2*sqrt(5))
517
+
518
+ assert tan(pi/6) == 1/sqrt(3)
519
+ assert tan(-pi/6) == -1/sqrt(3)
520
+ assert tan(pi*Rational(7, 6)) == 1/sqrt(3)
521
+ assert tan(pi*Rational(-5, 6)) == 1/sqrt(3)
522
+
523
+ assert tan(pi/8) == -1 + sqrt(2)
524
+ assert tan(pi*Rational(3, 8)) == 1 + sqrt(2) # issue 15959
525
+ assert tan(pi*Rational(5, 8)) == -1 - sqrt(2)
526
+ assert tan(pi*Rational(7, 8)) == 1 - sqrt(2)
527
+
528
+ assert tan(pi/10) == sqrt(1 - 2*sqrt(5)/5)
529
+ assert tan(pi*Rational(3, 10)) == sqrt(1 + 2*sqrt(5)/5)
530
+ assert tan(pi*Rational(17, 10)) == -sqrt(1 + 2*sqrt(5)/5)
531
+ assert tan(pi*Rational(-31, 10)) == -sqrt(1 - 2*sqrt(5)/5)
532
+
533
+ assert tan(pi/12) == -sqrt(3) + 2
534
+ assert tan(pi*Rational(5, 12)) == sqrt(3) + 2
535
+ assert tan(pi*Rational(7, 12)) == -sqrt(3) - 2
536
+ assert tan(pi*Rational(11, 12)) == sqrt(3) - 2
537
+
538
+ assert tan(pi/24).radsimp() == -2 - sqrt(3) + sqrt(2) + sqrt(6)
539
+ assert tan(pi*Rational(5, 24)).radsimp() == -2 + sqrt(3) - sqrt(2) + sqrt(6)
540
+ assert tan(pi*Rational(7, 24)).radsimp() == 2 - sqrt(3) - sqrt(2) + sqrt(6)
541
+ assert tan(pi*Rational(11, 24)).radsimp() == 2 + sqrt(3) + sqrt(2) + sqrt(6)
542
+ assert tan(pi*Rational(13, 24)).radsimp() == -2 - sqrt(3) - sqrt(2) - sqrt(6)
543
+ assert tan(pi*Rational(17, 24)).radsimp() == -2 + sqrt(3) + sqrt(2) - sqrt(6)
544
+ assert tan(pi*Rational(19, 24)).radsimp() == 2 - sqrt(3) + sqrt(2) - sqrt(6)
545
+ assert tan(pi*Rational(23, 24)).radsimp() == 2 + sqrt(3) - sqrt(2) - sqrt(6)
546
+
547
+ assert tan(x*I) == tanh(x)*I
548
+
549
+ assert tan(k*pi) == 0
550
+ assert tan(17*k*pi) == 0
551
+
552
+ assert tan(k*pi*I) == tanh(k*pi)*I
553
+
554
+ assert tan(r).is_real is None
555
+ assert tan(r).is_extended_real is True
556
+
557
+ assert tan(0, evaluate=False).is_algebraic
558
+ assert tan(a).is_algebraic is None
559
+ assert tan(na).is_algebraic is False
560
+
561
+ assert tan(pi*Rational(10, 7)) == tan(pi*Rational(3, 7))
562
+ assert tan(pi*Rational(11, 7)) == -tan(pi*Rational(3, 7))
563
+ assert tan(pi*Rational(-11, 7)) == tan(pi*Rational(3, 7))
564
+
565
+ assert tan(pi*Rational(15, 14)) == tan(pi/14)
566
+ assert tan(pi*Rational(-15, 14)) == -tan(pi/14)
567
+
568
+ assert tan(r).is_finite is None
569
+ assert tan(I*r).is_finite is True
570
+
571
+ # https://github.com/sympy/sympy/issues/21177
572
+ f = tan(pi*(x + S(3)/2))/(3*x)
573
+ assert f.as_leading_term(x) == -1/(3*pi*x**2)
574
+
575
+
576
+ def test_tan_series():
577
+ assert tan(x).series(x, 0, 9) == \
578
+ x + x**3/3 + 2*x**5/15 + 17*x**7/315 + O(x**9)
579
+
580
+
581
+ def test_tan_rewrite():
582
+ neg_exp, pos_exp = exp(-x*I), exp(x*I)
583
+ assert tan(x).rewrite(exp) == I*(neg_exp - pos_exp)/(neg_exp + pos_exp)
584
+ assert tan(x).rewrite(sin) == 2*sin(x)**2/sin(2*x)
585
+ assert tan(x).rewrite(cos) == cos(x - S.Pi/2, evaluate=False)/cos(x)
586
+ assert tan(x).rewrite(cot) == 1/cot(x)
587
+ assert tan(sinh(x)).rewrite(exp).subs(x, 3).n() == tan(x).rewrite(exp).subs(x, sinh(3)).n()
588
+ assert tan(cosh(x)).rewrite(exp).subs(x, 3).n() == tan(x).rewrite(exp).subs(x, cosh(3)).n()
589
+ assert tan(tanh(x)).rewrite(exp).subs(x, 3).n() == tan(x).rewrite(exp).subs(x, tanh(3)).n()
590
+ assert tan(coth(x)).rewrite(exp).subs(x, 3).n() == tan(x).rewrite(exp).subs(x, coth(3)).n()
591
+ assert tan(sin(x)).rewrite(exp).subs(x, 3).n() == tan(x).rewrite(exp).subs(x, sin(3)).n()
592
+ assert tan(cos(x)).rewrite(exp).subs(x, 3).n() == tan(x).rewrite(exp).subs(x, cos(3)).n()
593
+ assert tan(tan(x)).rewrite(exp).subs(x, 3).n() == tan(x).rewrite(exp).subs(x, tan(3)).n()
594
+ assert tan(cot(x)).rewrite(exp).subs(x, 3).n() == tan(x).rewrite(exp).subs(x, cot(3)).n()
595
+ assert tan(log(x)).rewrite(Pow) == I*(x**-I - x**I)/(x**-I + x**I)
596
+ assert tan(x).rewrite(sec) == sec(x)/sec(x - pi/2, evaluate=False)
597
+ assert tan(x).rewrite(csc) == csc(-x + pi/2, evaluate=False)/csc(x)
598
+ assert tan(sin(x)).rewrite(Pow) == tan(sin(x))
599
+
600
+
601
+ @slow
602
+ def test_tan_rewrite_slow():
603
+ assert 0 == (cos(pi/34)*tan(pi/34) - sin(pi/34)).rewrite(pow)
604
+ assert 0 == (cos(pi/17)*tan(pi/17) - sin(pi/17)).rewrite(pow)
605
+ assert tan(pi/19).rewrite(pow) == tan(pi/19)
606
+ assert tan(pi*Rational(8, 19)).rewrite(sqrt) == tan(pi*Rational(8, 19))
607
+ assert tan(pi*Rational(2, 5), evaluate=False).rewrite(sqrt) == sqrt(sqrt(5)/8 +
608
+ Rational(5, 8))/(Rational(-1, 4) + sqrt(5)/4)
609
+
610
+
611
+ def test_tan_subs():
612
+ assert tan(x).subs(tan(x), y) == y
613
+ assert tan(x).subs(x, y) == tan(y)
614
+ assert tan(x).subs(x, S.Pi/2) is zoo
615
+ assert tan(x).subs(x, S.Pi*Rational(3, 2)) is zoo
616
+
617
+
618
+ def test_tan_expansion():
619
+ assert tan(x + y).expand(trig=True) == ((tan(x) + tan(y))/(1 - tan(x)*tan(y))).expand()
620
+ assert tan(x - y).expand(trig=True) == ((tan(x) - tan(y))/(1 + tan(x)*tan(y))).expand()
621
+ assert tan(x + y + z).expand(trig=True) == (
622
+ (tan(x) + tan(y) + tan(z) - tan(x)*tan(y)*tan(z))/
623
+ (1 - tan(x)*tan(y) - tan(x)*tan(z) - tan(y)*tan(z))).expand()
624
+ assert 0 == tan(2*x).expand(trig=True).rewrite(tan).subs([(tan(x), Rational(1, 7))])*24 - 7
625
+ assert 0 == tan(3*x).expand(trig=True).rewrite(tan).subs([(tan(x), Rational(1, 5))])*55 - 37
626
+ assert 0 == tan(4*x - pi/4).expand(trig=True).rewrite(tan).subs([(tan(x), Rational(1, 5))])*239 - 1
627
+ _test_extrig(tan, 2, 2*tan(1)/(1 - tan(1)**2))
628
+ _test_extrig(tan, 3, (-tan(1)**3 + 3*tan(1))/(1 - 3*tan(1)**2))
629
+
630
+
631
+ def test_tan_AccumBounds():
632
+ assert tan(AccumBounds(-oo, oo)) == AccumBounds(-oo, oo)
633
+ assert tan(AccumBounds(S.Pi/3, S.Pi*Rational(2, 3))) == AccumBounds(-oo, oo)
634
+ assert tan(AccumBounds(S.Pi/6, S.Pi/3)) == AccumBounds(tan(S.Pi/6), tan(S.Pi/3))
635
+
636
+
637
+ def test_tan_fdiff():
638
+ assert tan(x).fdiff() == tan(x)**2 + 1
639
+ raises(ArgumentIndexError, lambda: tan(x).fdiff(2))
640
+
641
+
642
+ def test_cot():
643
+ assert cot(nan) is nan
644
+
645
+ assert cot.nargs == FiniteSet(1)
646
+ assert cot(oo*I) == -I
647
+ assert cot(-oo*I) == I
648
+ assert cot(zoo) is nan
649
+
650
+ assert cot(0) is zoo
651
+ assert cot(2*pi) is zoo
652
+
653
+ assert cot(acot(x)) == x
654
+ assert cot(atan(x)) == 1 / x
655
+ assert cot(asin(x)) == sqrt(1 - x**2) / x
656
+ assert cot(acos(x)) == x / sqrt(1 - x**2)
657
+ assert cot(acsc(x)) == sqrt(1 - 1 / x**2) * x
658
+ assert cot(asec(x)) == 1 / (sqrt(1 - 1 / x**2) * x)
659
+ assert cot(atan2(y, x)) == x/y
660
+
661
+ assert cot(pi*I) == -coth(pi)*I
662
+ assert cot(-pi*I) == coth(pi)*I
663
+ assert cot(-2*I) == coth(2)*I
664
+
665
+ assert cot(pi) == cot(2*pi) == cot(3*pi)
666
+ assert cot(-pi) == cot(-2*pi) == cot(-3*pi)
667
+
668
+ assert cot(pi/2) == 0
669
+ assert cot(-pi/2) == 0
670
+ assert cot(pi*Rational(5, 2)) == 0
671
+ assert cot(pi*Rational(7, 2)) == 0
672
+
673
+ assert cot(pi/3) == 1/sqrt(3)
674
+ assert cot(pi*Rational(-2, 3)) == 1/sqrt(3)
675
+
676
+ assert cot(pi/4) is S.One
677
+ assert cot(-pi/4) is S.NegativeOne
678
+ assert cot(pi*Rational(17, 4)) is S.One
679
+ assert cot(pi*Rational(-3, 4)) is S.One
680
+
681
+ assert cot(pi/6) == sqrt(3)
682
+ assert cot(-pi/6) == -sqrt(3)
683
+ assert cot(pi*Rational(7, 6)) == sqrt(3)
684
+ assert cot(pi*Rational(-5, 6)) == sqrt(3)
685
+
686
+ assert cot(pi/8) == 1 + sqrt(2)
687
+ assert cot(pi*Rational(3, 8)) == -1 + sqrt(2)
688
+ assert cot(pi*Rational(5, 8)) == 1 - sqrt(2)
689
+ assert cot(pi*Rational(7, 8)) == -1 - sqrt(2)
690
+
691
+ assert cot(pi/12) == sqrt(3) + 2
692
+ assert cot(pi*Rational(5, 12)) == -sqrt(3) + 2
693
+ assert cot(pi*Rational(7, 12)) == sqrt(3) - 2
694
+ assert cot(pi*Rational(11, 12)) == -sqrt(3) - 2
695
+
696
+ assert cot(pi/24).radsimp() == sqrt(2) + sqrt(3) + 2 + sqrt(6)
697
+ assert cot(pi*Rational(5, 24)).radsimp() == -sqrt(2) - sqrt(3) + 2 + sqrt(6)
698
+ assert cot(pi*Rational(7, 24)).radsimp() == -sqrt(2) + sqrt(3) - 2 + sqrt(6)
699
+ assert cot(pi*Rational(11, 24)).radsimp() == sqrt(2) - sqrt(3) - 2 + sqrt(6)
700
+ assert cot(pi*Rational(13, 24)).radsimp() == -sqrt(2) + sqrt(3) + 2 - sqrt(6)
701
+ assert cot(pi*Rational(17, 24)).radsimp() == sqrt(2) - sqrt(3) + 2 - sqrt(6)
702
+ assert cot(pi*Rational(19, 24)).radsimp() == sqrt(2) + sqrt(3) - 2 - sqrt(6)
703
+ assert cot(pi*Rational(23, 24)).radsimp() == -sqrt(2) - sqrt(3) - 2 - sqrt(6)
704
+
705
+ assert cot(x*I) == -coth(x)*I
706
+ assert cot(k*pi*I) == -coth(k*pi)*I
707
+
708
+ assert cot(r).is_real is None
709
+ assert cot(r).is_extended_real is True
710
+
711
+ assert cot(a).is_algebraic is None
712
+ assert cot(na).is_algebraic is False
713
+
714
+ assert cot(pi*Rational(10, 7)) == cot(pi*Rational(3, 7))
715
+ assert cot(pi*Rational(11, 7)) == -cot(pi*Rational(3, 7))
716
+ assert cot(pi*Rational(-11, 7)) == cot(pi*Rational(3, 7))
717
+
718
+ assert cot(pi*Rational(39, 34)) == cot(pi*Rational(5, 34))
719
+ assert cot(pi*Rational(-41, 34)) == -cot(pi*Rational(7, 34))
720
+
721
+ assert cot(x).is_finite is None
722
+ assert cot(r).is_finite is None
723
+ i = Symbol('i', imaginary=True)
724
+ assert cot(i).is_finite is True
725
+
726
+ assert cot(x).subs(x, 3*pi) is zoo
727
+
728
+ # https://github.com/sympy/sympy/issues/21177
729
+ f = cot(pi*(x + 4))/(3*x)
730
+ assert f.as_leading_term(x) == 1/(3*pi*x**2)
731
+
732
+
733
+ def test_tan_cot_sin_cos_evalf():
734
+ assert abs((tan(pi*Rational(8, 15))*cos(pi*Rational(8, 15))/sin(pi*Rational(8, 15)) - 1).evalf()) < 1e-14
735
+ assert abs((cot(pi*Rational(4, 15))*sin(pi*Rational(4, 15))/cos(pi*Rational(4, 15)) - 1).evalf()) < 1e-14
736
+
737
+ @XFAIL
738
+ def test_tan_cot_sin_cos_ratsimp():
739
+ assert 1 == (tan(pi*Rational(8, 15))*cos(pi*Rational(8, 15))/sin(pi*Rational(8, 15))).ratsimp()
740
+ assert 1 == (cot(pi*Rational(4, 15))*sin(pi*Rational(4, 15))/cos(pi*Rational(4, 15))).ratsimp()
741
+
742
+
743
+ def test_cot_series():
744
+ assert cot(x).series(x, 0, 9) == \
745
+ 1/x - x/3 - x**3/45 - 2*x**5/945 - x**7/4725 + O(x**9)
746
+ # issue 6210
747
+ assert cot(x**4 + x**5).series(x, 0, 1) == \
748
+ x**(-4) - 1/x**3 + x**(-2) - 1/x + 1 + O(x)
749
+ assert cot(pi*(1-x)).series(x, 0, 3) == -1/(pi*x) + pi*x/3 + O(x**3)
750
+ assert cot(x).taylor_term(0, x) == 1/x
751
+ assert cot(x).taylor_term(2, x) is S.Zero
752
+ assert cot(x).taylor_term(3, x) == -x**3/45
753
+
754
+
755
+ def test_cot_rewrite():
756
+ neg_exp, pos_exp = exp(-x*I), exp(x*I)
757
+ assert cot(x).rewrite(exp) == I*(pos_exp + neg_exp)/(pos_exp - neg_exp)
758
+ assert cot(x).rewrite(sin) == sin(2*x)/(2*(sin(x)**2))
759
+ assert cot(x).rewrite(cos) == cos(x)/cos(x - pi/2, evaluate=False)
760
+ assert cot(x).rewrite(tan) == 1/tan(x)
761
+ def check(func):
762
+ z = cot(func(x)).rewrite(exp) - cot(x).rewrite(exp).subs(x, func(x))
763
+ assert z.rewrite(exp).expand() == 0
764
+ check(sinh)
765
+ check(cosh)
766
+ check(tanh)
767
+ check(coth)
768
+ check(sin)
769
+ check(cos)
770
+ check(tan)
771
+ assert cot(log(x)).rewrite(Pow) == -I*(x**-I + x**I)/(x**-I - x**I)
772
+ assert cot(x).rewrite(sec) == sec(x - pi / 2, evaluate=False) / sec(x)
773
+ assert cot(x).rewrite(csc) == csc(x) / csc(- x + pi / 2, evaluate=False)
774
+ assert cot(sin(x)).rewrite(Pow) == cot(sin(x))
775
+
776
+
777
+ @slow
778
+ def test_cot_rewrite_slow():
779
+ assert cot(pi*Rational(4, 34)).rewrite(pow).ratsimp() == \
780
+ (cos(pi*Rational(4, 34))/sin(pi*Rational(4, 34))).rewrite(pow).ratsimp()
781
+ assert cot(pi*Rational(4, 17)).rewrite(pow) == \
782
+ (cos(pi*Rational(4, 17))/sin(pi*Rational(4, 17))).rewrite(pow)
783
+ assert cot(pi/19).rewrite(pow) == cot(pi/19)
784
+ assert cot(pi/19).rewrite(sqrt) == cot(pi/19)
785
+ assert cot(pi*Rational(2, 5), evaluate=False).rewrite(sqrt) == \
786
+ (Rational(-1, 4) + sqrt(5)/4) / sqrt(sqrt(5)/8 + Rational(5, 8))
787
+
788
+
789
+ def test_cot_subs():
790
+ assert cot(x).subs(cot(x), y) == y
791
+ assert cot(x).subs(x, y) == cot(y)
792
+ assert cot(x).subs(x, 0) is zoo
793
+ assert cot(x).subs(x, S.Pi) is zoo
794
+
795
+
796
+ def test_cot_expansion():
797
+ assert cot(x + y).expand(trig=True).together() == (
798
+ (cot(x)*cot(y) - 1)/(cot(x) + cot(y)))
799
+ assert cot(x - y).expand(trig=True).together() == (
800
+ cot(x)*cot(-y) - 1)/(cot(x) + cot(-y))
801
+ assert cot(x + y + z).expand(trig=True).together() == (
802
+ (cot(x)*cot(y)*cot(z) - cot(x) - cot(y) - cot(z))/
803
+ (-1 + cot(x)*cot(y) + cot(x)*cot(z) + cot(y)*cot(z)))
804
+ assert cot(3*x).expand(trig=True).together() == (
805
+ (cot(x)**2 - 3)*cot(x)/(3*cot(x)**2 - 1))
806
+ assert cot(2*x).expand(trig=True) == cot(x)/2 - 1/(2*cot(x))
807
+ assert cot(3*x).expand(trig=True).together() == (
808
+ cot(x)**2 - 3)*cot(x)/(3*cot(x)**2 - 1)
809
+ assert cot(4*x - pi/4).expand(trig=True).cancel() == (
810
+ -tan(x)**4 + 4*tan(x)**3 + 6*tan(x)**2 - 4*tan(x) - 1
811
+ )/(tan(x)**4 + 4*tan(x)**3 - 6*tan(x)**2 - 4*tan(x) + 1)
812
+ _test_extrig(cot, 2, (-1 + cot(1)**2)/(2*cot(1)))
813
+ _test_extrig(cot, 3, (-3*cot(1) + cot(1)**3)/(-1 + 3*cot(1)**2))
814
+
815
+
816
+ def test_cot_AccumBounds():
817
+ assert cot(AccumBounds(-oo, oo)) == AccumBounds(-oo, oo)
818
+ assert cot(AccumBounds(-S.Pi/3, S.Pi/3)) == AccumBounds(-oo, oo)
819
+ assert cot(AccumBounds(S.Pi/6, S.Pi/3)) == AccumBounds(cot(S.Pi/3), cot(S.Pi/6))
820
+
821
+
822
+ def test_cot_fdiff():
823
+ assert cot(x).fdiff() == -cot(x)**2 - 1
824
+ raises(ArgumentIndexError, lambda: cot(x).fdiff(2))
825
+
826
+
827
+ def test_sinc():
828
+ assert isinstance(sinc(x), sinc)
829
+
830
+ s = Symbol('s', zero=True)
831
+ assert sinc(s) is S.One
832
+ assert sinc(S.Infinity) is S.Zero
833
+ assert sinc(S.NegativeInfinity) is S.Zero
834
+ assert sinc(S.NaN) is S.NaN
835
+ assert sinc(S.ComplexInfinity) is S.NaN
836
+
837
+ n = Symbol('n', integer=True, nonzero=True)
838
+ assert sinc(n*pi) is S.Zero
839
+ assert sinc(-n*pi) is S.Zero
840
+ assert sinc(pi/2) == 2 / pi
841
+ assert sinc(-pi/2) == 2 / pi
842
+ assert sinc(pi*Rational(5, 2)) == 2 / (5*pi)
843
+ assert sinc(pi*Rational(7, 2)) == -2 / (7*pi)
844
+
845
+ assert sinc(-x) == sinc(x)
846
+
847
+ assert sinc(x).diff(x) == cos(x)/x - sin(x)/x**2
848
+ assert sinc(x).diff(x) == (sin(x)/x).diff(x)
849
+ assert sinc(x).diff(x, x) == (-sin(x) - 2*cos(x)/x + 2*sin(x)/x**2)/x
850
+ assert sinc(x).diff(x, x) == (sin(x)/x).diff(x, x)
851
+ assert limit(sinc(x).diff(x), x, 0) == 0
852
+ assert limit(sinc(x).diff(x, x), x, 0) == -S(1)/3
853
+
854
+ # https://github.com/sympy/sympy/issues/11402
855
+ #
856
+ # assert sinc(x).diff(x) == Piecewise(((x*cos(x) - sin(x)) / x**2, Ne(x, 0)), (0, True))
857
+ #
858
+ # assert sinc(x).diff(x).equals(sinc(x).rewrite(sin).diff(x))
859
+ #
860
+ # assert sinc(x).diff(x).subs(x, 0) is S.Zero
861
+
862
+ assert sinc(x).series() == 1 - x**2/6 + x**4/120 + O(x**6)
863
+
864
+ assert sinc(x).rewrite(jn) == jn(0, x)
865
+ assert sinc(x).rewrite(sin) == Piecewise((sin(x)/x, Ne(x, 0)), (1, True))
866
+ assert sinc(pi, evaluate=False).is_zero is True
867
+ assert sinc(0, evaluate=False).is_zero is False
868
+ assert sinc(n*pi, evaluate=False).is_zero is True
869
+ assert sinc(x).is_zero is None
870
+ xr = Symbol('xr', real=True, nonzero=True)
871
+ assert sinc(x).is_real is None
872
+ assert sinc(xr).is_real is True
873
+ assert sinc(I*xr).is_real is True
874
+ assert sinc(I*100).is_real is True
875
+ assert sinc(x).is_finite is None
876
+ assert sinc(xr).is_finite is True
877
+
878
+
879
+ def test_asin():
880
+ assert asin(nan) is nan
881
+
882
+ assert asin.nargs == FiniteSet(1)
883
+ assert asin(oo) == -I*oo
884
+ assert asin(-oo) == I*oo
885
+ assert asin(zoo) is zoo
886
+
887
+ # Note: asin(-x) = - asin(x)
888
+ assert asin(0) == 0
889
+ assert asin(1) == pi/2
890
+ assert asin(-1) == -pi/2
891
+ assert asin(sqrt(3)/2) == pi/3
892
+ assert asin(-sqrt(3)/2) == -pi/3
893
+ assert asin(sqrt(2)/2) == pi/4
894
+ assert asin(-sqrt(2)/2) == -pi/4
895
+ assert asin(sqrt((5 - sqrt(5))/8)) == pi/5
896
+ assert asin(-sqrt((5 - sqrt(5))/8)) == -pi/5
897
+ assert asin(S.Half) == pi/6
898
+ assert asin(Rational(-1, 2)) == -pi/6
899
+ assert asin((sqrt(2 - sqrt(2)))/2) == pi/8
900
+ assert asin(-(sqrt(2 - sqrt(2)))/2) == -pi/8
901
+ assert asin((sqrt(5) - 1)/4) == pi/10
902
+ assert asin(-(sqrt(5) - 1)/4) == -pi/10
903
+ assert asin((sqrt(3) - 1)/sqrt(2**3)) == pi/12
904
+ assert asin(-(sqrt(3) - 1)/sqrt(2**3)) == -pi/12
905
+
906
+ # check round-trip for exact values:
907
+ for d in [5, 6, 8, 10, 12]:
908
+ for n in range(-(d//2), d//2 + 1):
909
+ if gcd(n, d) == 1:
910
+ assert asin(sin(n*pi/d)) == n*pi/d
911
+
912
+ assert asin(x).diff(x) == 1/sqrt(1 - x**2)
913
+
914
+ assert asin(0.2, evaluate=False).is_real is True
915
+ assert asin(-2).is_real is False
916
+ assert asin(r).is_real is None
917
+
918
+ assert asin(-2*I) == -I*asinh(2)
919
+
920
+ assert asin(Rational(1, 7), evaluate=False).is_positive is True
921
+ assert asin(Rational(-1, 7), evaluate=False).is_positive is False
922
+ assert asin(p).is_positive is None
923
+ assert asin(sin(Rational(7, 2))) == Rational(-7, 2) + pi
924
+ assert asin(sin(Rational(-7, 4))) == Rational(7, 4) - pi
925
+ assert unchanged(asin, cos(x))
926
+
927
+
928
+ def test_asin_series():
929
+ assert asin(x).series(x, 0, 9) == \
930
+ x + x**3/6 + 3*x**5/40 + 5*x**7/112 + O(x**9)
931
+ t5 = asin(x).taylor_term(5, x)
932
+ assert t5 == 3*x**5/40
933
+ assert asin(x).taylor_term(7, x, t5, 0) == 5*x**7/112
934
+
935
+
936
+ def test_asin_leading_term():
937
+ assert asin(x).as_leading_term(x) == x
938
+ # Tests concerning branch points
939
+ assert asin(x + 1).as_leading_term(x) == pi/2
940
+ assert asin(x - 1).as_leading_term(x) == -pi/2
941
+ assert asin(1/x).as_leading_term(x, cdir=1) == I*log(x) + pi/2 - I*log(2)
942
+ assert asin(1/x).as_leading_term(x, cdir=-1) == -I*log(x) - 3*pi/2 + I*log(2)
943
+ # Tests concerning points lying on branch cuts
944
+ assert asin(I*x + 2).as_leading_term(x, cdir=1) == pi - asin(2)
945
+ assert asin(-I*x + 2).as_leading_term(x, cdir=1) == asin(2)
946
+ assert asin(I*x - 2).as_leading_term(x, cdir=1) == -asin(2)
947
+ assert asin(-I*x - 2).as_leading_term(x, cdir=1) == -pi + asin(2)
948
+ # Tests concerning im(ndir) == 0
949
+ assert asin(-I*x**2 + x - 2).as_leading_term(x, cdir=1) == -pi/2 + I*log(2 - sqrt(3))
950
+ assert asin(-I*x**2 + x - 2).as_leading_term(x, cdir=-1) == -pi/2 + I*log(2 - sqrt(3))
951
+
952
+
953
+ def test_asin_rewrite():
954
+ assert asin(x).rewrite(log) == -I*log(I*x + sqrt(1 - x**2))
955
+ assert asin(x).rewrite(atan) == 2*atan(x/(1 + sqrt(1 - x**2)))
956
+ assert asin(x).rewrite(acos) == S.Pi/2 - acos(x)
957
+ assert asin(x).rewrite(acot) == 2*acot((sqrt(-x**2 + 1) + 1)/x)
958
+ assert asin(x).rewrite(asec) == -asec(1/x) + pi/2
959
+ assert asin(x).rewrite(acsc) == acsc(1/x)
960
+
961
+
962
+ def test_asin_fdiff():
963
+ assert asin(x).fdiff() == 1/sqrt(1 - x**2)
964
+ raises(ArgumentIndexError, lambda: asin(x).fdiff(2))
965
+
966
+
967
+ def test_acos():
968
+ assert acos(nan) is nan
969
+ assert acos(zoo) is zoo
970
+
971
+ assert acos.nargs == FiniteSet(1)
972
+ assert acos(oo) == I*oo
973
+ assert acos(-oo) == -I*oo
974
+
975
+ # Note: acos(-x) = pi - acos(x)
976
+ assert acos(0) == pi/2
977
+ assert acos(S.Half) == pi/3
978
+ assert acos(Rational(-1, 2)) == pi*Rational(2, 3)
979
+ assert acos(1) == 0
980
+ assert acos(-1) == pi
981
+ assert acos(sqrt(2)/2) == pi/4
982
+ assert acos(-sqrt(2)/2) == pi*Rational(3, 4)
983
+
984
+ # check round-trip for exact values:
985
+ for d in [5, 6, 8, 10, 12]:
986
+ for num in range(d):
987
+ if gcd(num, d) == 1:
988
+ assert acos(cos(num*pi/d)) == num*pi/d
989
+
990
+ assert acos(2*I) == pi/2 - asin(2*I)
991
+
992
+ assert acos(x).diff(x) == -1/sqrt(1 - x**2)
993
+
994
+ assert acos(0.2).is_real is True
995
+ assert acos(-2).is_real is False
996
+ assert acos(r).is_real is None
997
+
998
+ assert acos(Rational(1, 7), evaluate=False).is_positive is True
999
+ assert acos(Rational(-1, 7), evaluate=False).is_positive is True
1000
+ assert acos(Rational(3, 2), evaluate=False).is_positive is False
1001
+ assert acos(p).is_positive is None
1002
+
1003
+ assert acos(2 + p).conjugate() != acos(10 + p)
1004
+ assert acos(-3 + n).conjugate() != acos(-3 + n)
1005
+ assert acos(Rational(1, 3)).conjugate() == acos(Rational(1, 3))
1006
+ assert acos(Rational(-1, 3)).conjugate() == acos(Rational(-1, 3))
1007
+ assert acos(p + n*I).conjugate() == acos(p - n*I)
1008
+ assert acos(z).conjugate() != acos(conjugate(z))
1009
+
1010
+
1011
+ def test_acos_leading_term():
1012
+ assert acos(x).as_leading_term(x) == pi/2
1013
+ # Tests concerning branch points
1014
+ assert acos(x + 1).as_leading_term(x) == sqrt(2)*sqrt(-x)
1015
+ assert acos(x - 1).as_leading_term(x) == pi
1016
+ assert acos(1/x).as_leading_term(x, cdir=1) == -I*log(x) + I*log(2)
1017
+ assert acos(1/x).as_leading_term(x, cdir=-1) == I*log(x) + 2*pi - I*log(2)
1018
+ # Tests concerning points lying on branch cuts
1019
+ assert acos(I*x + 2).as_leading_term(x, cdir=1) == -acos(2)
1020
+ assert acos(-I*x + 2).as_leading_term(x, cdir=1) == acos(2)
1021
+ assert acos(I*x - 2).as_leading_term(x, cdir=1) == acos(-2)
1022
+ assert acos(-I*x - 2).as_leading_term(x, cdir=1) == 2*pi - acos(-2)
1023
+ # Tests concerning im(ndir) == 0
1024
+ assert acos(-I*x**2 + x - 2).as_leading_term(x, cdir=1) == pi + I*log(sqrt(3) + 2)
1025
+ assert acos(-I*x**2 + x - 2).as_leading_term(x, cdir=-1) == pi + I*log(sqrt(3) + 2)
1026
+
1027
+
1028
+ def test_acos_series():
1029
+ assert acos(x).series(x, 0, 8) == \
1030
+ pi/2 - x - x**3/6 - 3*x**5/40 - 5*x**7/112 + O(x**8)
1031
+ assert acos(x).series(x, 0, 8) == pi/2 - asin(x).series(x, 0, 8)
1032
+ t5 = acos(x).taylor_term(5, x)
1033
+ assert t5 == -3*x**5/40
1034
+ assert acos(x).taylor_term(7, x, t5, 0) == -5*x**7/112
1035
+ assert acos(x).taylor_term(0, x) == pi/2
1036
+ assert acos(x).taylor_term(2, x) is S.Zero
1037
+
1038
+
1039
+ def test_acos_rewrite():
1040
+ assert acos(x).rewrite(log) == pi/2 + I*log(I*x + sqrt(1 - x**2))
1041
+ assert acos(x).rewrite(atan) == pi*(-x*sqrt(x**(-2)) + 1)/2 + atan(sqrt(1 - x**2)/x)
1042
+ assert acos(0).rewrite(atan) == S.Pi/2
1043
+ assert acos(0.5).rewrite(atan) == acos(0.5).rewrite(log)
1044
+ assert acos(x).rewrite(asin) == S.Pi/2 - asin(x)
1045
+ assert acos(x).rewrite(acot) == -2*acot((sqrt(-x**2 + 1) + 1)/x) + pi/2
1046
+ assert acos(x).rewrite(asec) == asec(1/x)
1047
+ assert acos(x).rewrite(acsc) == -acsc(1/x) + pi/2
1048
+
1049
+
1050
+ def test_acos_fdiff():
1051
+ assert acos(x).fdiff() == -1/sqrt(1 - x**2)
1052
+ raises(ArgumentIndexError, lambda: acos(x).fdiff(2))
1053
+
1054
+
1055
+ def test_atan():
1056
+ assert atan(nan) is nan
1057
+
1058
+ assert atan.nargs == FiniteSet(1)
1059
+ assert atan(oo) == pi/2
1060
+ assert atan(-oo) == -pi/2
1061
+ assert atan(zoo) == AccumBounds(-pi/2, pi/2)
1062
+
1063
+ assert atan(0) == 0
1064
+ assert atan(1) == pi/4
1065
+ assert atan(sqrt(3)) == pi/3
1066
+ assert atan(-(1 + sqrt(2))) == pi*Rational(-3, 8)
1067
+ assert atan(sqrt(5 - 2 * sqrt(5))) == pi/5
1068
+ assert atan(-sqrt(1 - 2 * sqrt(5)/ 5)) == -pi/10
1069
+ assert atan(sqrt(1 + 2 * sqrt(5) / 5)) == pi*Rational(3, 10)
1070
+ assert atan(-2 + sqrt(3)) == -pi/12
1071
+ assert atan(2 + sqrt(3)) == pi*Rational(5, 12)
1072
+ assert atan(-2 - sqrt(3)) == pi*Rational(-5, 12)
1073
+
1074
+ # check round-trip for exact values:
1075
+ for d in [5, 6, 8, 10, 12]:
1076
+ for num in range(-(d//2), d//2 + 1):
1077
+ if gcd(num, d) == 1:
1078
+ assert atan(tan(num*pi/d)) == num*pi/d
1079
+
1080
+ assert atan(oo) == pi/2
1081
+ assert atan(x).diff(x) == 1/(1 + x**2)
1082
+
1083
+ assert atan(r).is_real is True
1084
+
1085
+ assert atan(-2*I) == -I*atanh(2)
1086
+ assert unchanged(atan, cot(x))
1087
+ assert atan(cot(Rational(1, 4))) == Rational(-1, 4) + pi/2
1088
+ assert acot(Rational(1, 4)).is_rational is False
1089
+
1090
+ for s in (x, p, n, np, nn, nz, ep, en, enp, enn, enz):
1091
+ if s.is_real or s.is_extended_real is None:
1092
+ assert s.is_nonzero is atan(s).is_nonzero
1093
+ assert s.is_positive is atan(s).is_positive
1094
+ assert s.is_negative is atan(s).is_negative
1095
+ assert s.is_nonpositive is atan(s).is_nonpositive
1096
+ assert s.is_nonnegative is atan(s).is_nonnegative
1097
+ else:
1098
+ assert s.is_extended_nonzero is atan(s).is_nonzero
1099
+ assert s.is_extended_positive is atan(s).is_positive
1100
+ assert s.is_extended_negative is atan(s).is_negative
1101
+ assert s.is_extended_nonpositive is atan(s).is_nonpositive
1102
+ assert s.is_extended_nonnegative is atan(s).is_nonnegative
1103
+ assert s.is_extended_nonzero is atan(s).is_extended_nonzero
1104
+ assert s.is_extended_positive is atan(s).is_extended_positive
1105
+ assert s.is_extended_negative is atan(s).is_extended_negative
1106
+ assert s.is_extended_nonpositive is atan(s).is_extended_nonpositive
1107
+ assert s.is_extended_nonnegative is atan(s).is_extended_nonnegative
1108
+
1109
+
1110
+ def test_atan_rewrite():
1111
+ assert atan(x).rewrite(log) == I*(log(1 - I*x)-log(1 + I*x))/2
1112
+ assert atan(x).rewrite(asin) == (-asin(1/sqrt(x**2 + 1)) + pi/2)*sqrt(x**2)/x
1113
+ assert atan(x).rewrite(acos) == sqrt(x**2)*acos(1/sqrt(x**2 + 1))/x
1114
+ assert atan(x).rewrite(acot) == acot(1/x)
1115
+ assert atan(x).rewrite(asec) == sqrt(x**2)*asec(sqrt(x**2 + 1))/x
1116
+ assert atan(x).rewrite(acsc) == (-acsc(sqrt(x**2 + 1)) + pi/2)*sqrt(x**2)/x
1117
+
1118
+ assert atan(-5*I).evalf() == atan(x).rewrite(log).evalf(subs={x:-5*I})
1119
+ assert atan(5*I).evalf() == atan(x).rewrite(log).evalf(subs={x:5*I})
1120
+
1121
+
1122
+ def test_atan_fdiff():
1123
+ assert atan(x).fdiff() == 1/(x**2 + 1)
1124
+ raises(ArgumentIndexError, lambda: atan(x).fdiff(2))
1125
+
1126
+
1127
+ def test_atan_leading_term():
1128
+ assert atan(x).as_leading_term(x) == x
1129
+ assert atan(1/x).as_leading_term(x, cdir=1) == pi/2
1130
+ assert atan(1/x).as_leading_term(x, cdir=-1) == -pi/2
1131
+ # Tests concerning branch points
1132
+ assert atan(x + I).as_leading_term(x, cdir=1) == -I*log(x)/2 + pi/4 + I*log(2)/2
1133
+ assert atan(x + I).as_leading_term(x, cdir=-1) == -I*log(x)/2 - 3*pi/4 + I*log(2)/2
1134
+ assert atan(x - I).as_leading_term(x, cdir=1) == I*log(x)/2 + pi/4 - I*log(2)/2
1135
+ assert atan(x - I).as_leading_term(x, cdir=-1) == I*log(x)/2 + pi/4 - I*log(2)/2
1136
+ # Tests concerning points lying on branch cuts
1137
+ assert atan(x + 2*I).as_leading_term(x, cdir=1) == I*atanh(2)
1138
+ assert atan(x + 2*I).as_leading_term(x, cdir=-1) == -pi + I*atanh(2)
1139
+ assert atan(x - 2*I).as_leading_term(x, cdir=1) == pi - I*atanh(2)
1140
+ assert atan(x - 2*I).as_leading_term(x, cdir=-1) == -I*atanh(2)
1141
+ # Tests concerning re(ndir) == 0
1142
+ assert atan(2*I - I*x - x**2).as_leading_term(x, cdir=1) == -pi/2 + I*log(3)/2
1143
+ assert atan(2*I - I*x - x**2).as_leading_term(x, cdir=-1) == -pi/2 + I*log(3)/2
1144
+
1145
+
1146
+ def test_atan2():
1147
+ assert atan2.nargs == FiniteSet(2)
1148
+ assert atan2(0, 0) is S.NaN
1149
+ assert atan2(0, 1) == 0
1150
+ assert atan2(1, 1) == pi/4
1151
+ assert atan2(1, 0) == pi/2
1152
+ assert atan2(1, -1) == pi*Rational(3, 4)
1153
+ assert atan2(0, -1) == pi
1154
+ assert atan2(-1, -1) == pi*Rational(-3, 4)
1155
+ assert atan2(-1, 0) == -pi/2
1156
+ assert atan2(-1, 1) == -pi/4
1157
+ i = symbols('i', imaginary=True)
1158
+ r = symbols('r', real=True)
1159
+ eq = atan2(r, i)
1160
+ ans = -I*log((i + I*r)/sqrt(i**2 + r**2))
1161
+ reps = ((r, 2), (i, I))
1162
+ assert eq.subs(reps) == ans.subs(reps)
1163
+
1164
+ x = Symbol('x', negative=True)
1165
+ y = Symbol('y', negative=True)
1166
+ assert atan2(y, x) == atan(y/x) - pi
1167
+ y = Symbol('y', nonnegative=True)
1168
+ assert atan2(y, x) == atan(y/x) + pi
1169
+ y = Symbol('y')
1170
+ assert atan2(y, x) == atan2(y, x, evaluate=False)
1171
+
1172
+ u = Symbol("u", positive=True)
1173
+ assert atan2(0, u) == 0
1174
+ u = Symbol("u", negative=True)
1175
+ assert atan2(0, u) == pi
1176
+
1177
+ assert atan2(y, oo) == 0
1178
+ assert atan2(y, -oo)== 2*pi*Heaviside(re(y), S.Half) - pi
1179
+
1180
+ assert atan2(y, x).rewrite(log) == -I*log((x + I*y)/sqrt(x**2 + y**2))
1181
+ assert atan2(0, 0) is S.NaN
1182
+
1183
+ ex = atan2(y, x) - arg(x + I*y)
1184
+ assert ex.subs({x:2, y:3}).rewrite(arg) == 0
1185
+ assert ex.subs({x:2, y:3*I}).rewrite(arg) == -pi - I*log(sqrt(5)*I/5)
1186
+ assert ex.subs({x:2*I, y:3}).rewrite(arg) == -pi/2 - I*log(sqrt(5)*I)
1187
+ assert ex.subs({x:2*I, y:3*I}).rewrite(arg) == -pi + atan(Rational(2, 3)) + atan(Rational(3, 2))
1188
+ i = symbols('i', imaginary=True)
1189
+ r = symbols('r', real=True)
1190
+ e = atan2(i, r)
1191
+ rewrite = e.rewrite(arg)
1192
+ reps = {i: I, r: -2}
1193
+ assert rewrite == -I*log(abs(I*i + r)/sqrt(abs(i**2 + r**2))) + arg((I*i + r)/sqrt(i**2 + r**2))
1194
+ assert (e - rewrite).subs(reps).equals(0)
1195
+
1196
+ assert atan2(0, x).rewrite(atan) == Piecewise((pi, re(x) < 0),
1197
+ (0, Ne(x, 0)),
1198
+ (nan, True))
1199
+ assert atan2(0, r).rewrite(atan) == Piecewise((pi, r < 0), (0, Ne(r, 0)), (S.NaN, True))
1200
+ assert atan2(0, i),rewrite(atan) == 0
1201
+ assert atan2(0, r + i).rewrite(atan) == Piecewise((pi, r < 0), (0, True))
1202
+
1203
+ assert atan2(y, x).rewrite(atan) == Piecewise(
1204
+ (2*atan(y/(x + sqrt(x**2 + y**2))), Ne(y, 0)),
1205
+ (pi, re(x) < 0),
1206
+ (0, (re(x) > 0) | Ne(im(x), 0)),
1207
+ (nan, True))
1208
+ assert conjugate(atan2(x, y)) == atan2(conjugate(x), conjugate(y))
1209
+
1210
+ assert diff(atan2(y, x), x) == -y/(x**2 + y**2)
1211
+ assert diff(atan2(y, x), y) == x/(x**2 + y**2)
1212
+
1213
+ assert simplify(diff(atan2(y, x).rewrite(log), x)) == -y/(x**2 + y**2)
1214
+ assert simplify(diff(atan2(y, x).rewrite(log), y)) == x/(x**2 + y**2)
1215
+
1216
+ assert str(atan2(1, 2).evalf(5)) == '0.46365'
1217
+ raises(ArgumentIndexError, lambda: atan2(x, y).fdiff(3))
1218
+
1219
+ def test_issue_17461():
1220
+ class A(Symbol):
1221
+ is_extended_real = True
1222
+
1223
+ def _eval_evalf(self, prec):
1224
+ return Float(5.0)
1225
+
1226
+ x = A('X')
1227
+ y = A('Y')
1228
+ assert abs(atan2(x, y).evalf() - 0.785398163397448) <= 1e-10
1229
+
1230
+ def test_acot():
1231
+ assert acot(nan) is nan
1232
+
1233
+ assert acot.nargs == FiniteSet(1)
1234
+ assert acot(-oo) == 0
1235
+ assert acot(oo) == 0
1236
+ assert acot(zoo) == 0
1237
+ assert acot(1) == pi/4
1238
+ assert acot(0) == pi/2
1239
+ assert acot(sqrt(3)/3) == pi/3
1240
+ assert acot(1/sqrt(3)) == pi/3
1241
+ assert acot(-1/sqrt(3)) == -pi/3
1242
+ assert acot(x).diff(x) == -1/(1 + x**2)
1243
+
1244
+ assert acot(r).is_extended_real is True
1245
+
1246
+ assert acot(I*pi) == -I*acoth(pi)
1247
+ assert acot(-2*I) == I*acoth(2)
1248
+ assert acot(x).is_positive is None
1249
+ assert acot(n).is_positive is False
1250
+ assert acot(p).is_positive is True
1251
+ assert acot(I).is_positive is False
1252
+ assert acot(Rational(1, 4)).is_rational is False
1253
+ assert unchanged(acot, cot(x))
1254
+ assert unchanged(acot, tan(x))
1255
+ assert acot(cot(Rational(1, 4))) == Rational(1, 4)
1256
+ assert acot(tan(Rational(-1, 4))) == Rational(1, 4) - pi/2
1257
+
1258
+
1259
+ def test_acot_rewrite():
1260
+ assert acot(x).rewrite(log) == I*(log(1 - I/x)-log(1 + I/x))/2
1261
+ assert acot(x).rewrite(asin) == x*(-asin(sqrt(-x**2)/sqrt(-x**2 - 1)) + pi/2)*sqrt(x**(-2))
1262
+ assert acot(x).rewrite(acos) == x*sqrt(x**(-2))*acos(sqrt(-x**2)/sqrt(-x**2 - 1))
1263
+ assert acot(x).rewrite(atan) == atan(1/x)
1264
+ assert acot(x).rewrite(asec) == x*sqrt(x**(-2))*asec(sqrt((x**2 + 1)/x**2))
1265
+ assert acot(x).rewrite(acsc) == x*(-acsc(sqrt((x**2 + 1)/x**2)) + pi/2)*sqrt(x**(-2))
1266
+
1267
+ assert acot(-I/5).evalf() == acot(x).rewrite(log).evalf(subs={x:-I/5})
1268
+ assert acot(I/5).evalf() == acot(x).rewrite(log).evalf(subs={x:I/5})
1269
+
1270
+
1271
+ def test_acot_fdiff():
1272
+ assert acot(x).fdiff() == -1/(x**2 + 1)
1273
+ raises(ArgumentIndexError, lambda: acot(x).fdiff(2))
1274
+
1275
+ def test_acot_leading_term():
1276
+ assert acot(1/x).as_leading_term(x) == x
1277
+ # Tests concerning branch points
1278
+ assert acot(x + I).as_leading_term(x, cdir=1) == I*log(x)/2 + pi/4 - I*log(2)/2
1279
+ assert acot(x + I).as_leading_term(x, cdir=-1) == I*log(x)/2 + pi/4 - I*log(2)/2
1280
+ assert acot(x - I).as_leading_term(x, cdir=1) == -I*log(x)/2 + pi/4 + I*log(2)/2
1281
+ assert acot(x - I).as_leading_term(x, cdir=-1) == -I*log(x)/2 - 3*pi/4 + I*log(2)/2
1282
+ # Tests concerning points lying on branch cuts
1283
+ assert acot(x).as_leading_term(x, cdir=1) == pi/2
1284
+ assert acot(x).as_leading_term(x, cdir=-1) == -pi/2
1285
+ assert acot(x + I/2).as_leading_term(x, cdir=1) == pi - I*acoth(S(1)/2)
1286
+ assert acot(x + I/2).as_leading_term(x, cdir=-1) == -I*acoth(S(1)/2)
1287
+ assert acot(x - I/2).as_leading_term(x, cdir=1) == I*acoth(S(1)/2)
1288
+ assert acot(x - I/2).as_leading_term(x, cdir=-1) == -pi + I*acoth(S(1)/2)
1289
+ # Tests concerning re(ndir) == 0
1290
+ assert acot(I/2 - I*x - x**2).as_leading_term(x, cdir=1) == -pi/2 - I*log(3)/2
1291
+ assert acot(I/2 - I*x - x**2).as_leading_term(x, cdir=-1) == -pi/2 - I*log(3)/2
1292
+
1293
+
1294
+ def test_attributes():
1295
+ assert sin(x).args == (x,)
1296
+
1297
+
1298
+ def test_sincos_rewrite():
1299
+ assert sin(pi/2 - x) == cos(x)
1300
+ assert sin(pi - x) == sin(x)
1301
+ assert cos(pi/2 - x) == sin(x)
1302
+ assert cos(pi - x) == -cos(x)
1303
+
1304
+
1305
+ def _check_even_rewrite(func, arg):
1306
+ """Checks that the expr has been rewritten using f(-x) -> f(x)
1307
+ arg : -x
1308
+ """
1309
+ return func(arg).args[0] == -arg
1310
+
1311
+
1312
+ def _check_odd_rewrite(func, arg):
1313
+ """Checks that the expr has been rewritten using f(-x) -> -f(x)
1314
+ arg : -x
1315
+ """
1316
+ return func(arg).func.is_Mul
1317
+
1318
+
1319
+ def _check_no_rewrite(func, arg):
1320
+ """Checks that the expr is not rewritten"""
1321
+ return func(arg).args[0] == arg
1322
+
1323
+
1324
+ def test_evenodd_rewrite():
1325
+ a = cos(2) # negative
1326
+ b = sin(1) # positive
1327
+ even = [cos]
1328
+ odd = [sin, tan, cot, asin, atan, acot]
1329
+ with_minus = [-1, -2**1024 * E, -pi/105, -x*y, -x - y]
1330
+ for func in even:
1331
+ for expr in with_minus:
1332
+ assert _check_even_rewrite(func, expr)
1333
+ assert _check_no_rewrite(func, a*b)
1334
+ assert func(
1335
+ x - y) == func(y - x) # it doesn't matter which form is canonical
1336
+ for func in odd:
1337
+ for expr in with_minus:
1338
+ assert _check_odd_rewrite(func, expr)
1339
+ assert _check_no_rewrite(func, a*b)
1340
+ assert func(
1341
+ x - y) == -func(y - x) # it doesn't matter which form is canonical
1342
+
1343
+
1344
+ def test_as_leading_term_issue_5272():
1345
+ assert sin(x).as_leading_term(x) == x
1346
+ assert cos(x).as_leading_term(x) == 1
1347
+ assert tan(x).as_leading_term(x) == x
1348
+ assert cot(x).as_leading_term(x) == 1/x
1349
+
1350
+
1351
+ def test_leading_terms():
1352
+ assert sin(1/x).as_leading_term(x) == AccumBounds(-1, 1)
1353
+ assert sin(S.Half).as_leading_term(x) == sin(S.Half)
1354
+ assert cos(1/x).as_leading_term(x) == AccumBounds(-1, 1)
1355
+ assert cos(S.Half).as_leading_term(x) == cos(S.Half)
1356
+ assert sec(1/x).as_leading_term(x) == AccumBounds(S.NegativeInfinity, S.Infinity)
1357
+ assert csc(1/x).as_leading_term(x) == AccumBounds(S.NegativeInfinity, S.Infinity)
1358
+ assert tan(1/x).as_leading_term(x) == AccumBounds(S.NegativeInfinity, S.Infinity)
1359
+ assert cot(1/x).as_leading_term(x) == AccumBounds(S.NegativeInfinity, S.Infinity)
1360
+
1361
+ # https://github.com/sympy/sympy/issues/21038
1362
+ f = sin(pi*(x + 4))/(3*x)
1363
+ assert f.as_leading_term(x) == pi/3
1364
+
1365
+
1366
+ def test_atan2_expansion():
1367
+ assert cancel(atan2(x**2, x + 1).diff(x) - atan(x**2/(x + 1)).diff(x)) == 0
1368
+ assert cancel(atan(y/x).series(y, 0, 5) - atan2(y, x).series(y, 0, 5)
1369
+ + atan2(0, x) - atan(0)) == O(y**5)
1370
+ assert cancel(atan(y/x).series(x, 1, 4) - atan2(y, x).series(x, 1, 4)
1371
+ + atan2(y, 1) - atan(y)) == O((x - 1)**4, (x, 1))
1372
+ assert cancel(atan((y + x)/x).series(x, 1, 3) - atan2(y + x, x).series(x, 1, 3)
1373
+ + atan2(1 + y, 1) - atan(1 + y)) == O((x - 1)**3, (x, 1))
1374
+ assert Matrix([atan2(y, x)]).jacobian([y, x]) == \
1375
+ Matrix([[x/(y**2 + x**2), -y/(y**2 + x**2)]])
1376
+
1377
+
1378
+ def test_aseries():
1379
+ def t(n, v, d, e):
1380
+ assert abs(
1381
+ n(1/v).evalf() - n(1/x).series(x, dir=d).removeO().subs(x, v)) < e
1382
+ t(atan, 0.1, '+', 1e-5)
1383
+ t(atan, -0.1, '-', 1e-5)
1384
+ t(acot, 0.1, '+', 1e-5)
1385
+ t(acot, -0.1, '-', 1e-5)
1386
+
1387
+
1388
+ def test_issue_4420():
1389
+ i = Symbol('i', integer=True)
1390
+ e = Symbol('e', even=True)
1391
+ o = Symbol('o', odd=True)
1392
+
1393
+ # unknown parity for variable
1394
+ assert cos(4*i*pi) == 1
1395
+ assert sin(4*i*pi) == 0
1396
+ assert tan(4*i*pi) == 0
1397
+ assert cot(4*i*pi) is zoo
1398
+
1399
+ assert cos(3*i*pi) == cos(pi*i) # +/-1
1400
+ assert sin(3*i*pi) == 0
1401
+ assert tan(3*i*pi) == 0
1402
+ assert cot(3*i*pi) is zoo
1403
+
1404
+ assert cos(4.0*i*pi) == 1
1405
+ assert sin(4.0*i*pi) == 0
1406
+ assert tan(4.0*i*pi) == 0
1407
+ assert cot(4.0*i*pi) is zoo
1408
+
1409
+ assert cos(3.0*i*pi) == cos(pi*i) # +/-1
1410
+ assert sin(3.0*i*pi) == 0
1411
+ assert tan(3.0*i*pi) == 0
1412
+ assert cot(3.0*i*pi) is zoo
1413
+
1414
+ assert cos(4.5*i*pi) == cos(0.5*pi*i)
1415
+ assert sin(4.5*i*pi) == sin(0.5*pi*i)
1416
+ assert tan(4.5*i*pi) == tan(0.5*pi*i)
1417
+ assert cot(4.5*i*pi) == cot(0.5*pi*i)
1418
+
1419
+ # parity of variable is known
1420
+ assert cos(4*e*pi) == 1
1421
+ assert sin(4*e*pi) == 0
1422
+ assert tan(4*e*pi) == 0
1423
+ assert cot(4*e*pi) is zoo
1424
+
1425
+ assert cos(3*e*pi) == 1
1426
+ assert sin(3*e*pi) == 0
1427
+ assert tan(3*e*pi) == 0
1428
+ assert cot(3*e*pi) is zoo
1429
+
1430
+ assert cos(4.0*e*pi) == 1
1431
+ assert sin(4.0*e*pi) == 0
1432
+ assert tan(4.0*e*pi) == 0
1433
+ assert cot(4.0*e*pi) is zoo
1434
+
1435
+ assert cos(3.0*e*pi) == 1
1436
+ assert sin(3.0*e*pi) == 0
1437
+ assert tan(3.0*e*pi) == 0
1438
+ assert cot(3.0*e*pi) is zoo
1439
+
1440
+ assert cos(4.5*e*pi) == cos(0.5*pi*e)
1441
+ assert sin(4.5*e*pi) == sin(0.5*pi*e)
1442
+ assert tan(4.5*e*pi) == tan(0.5*pi*e)
1443
+ assert cot(4.5*e*pi) == cot(0.5*pi*e)
1444
+
1445
+ assert cos(4*o*pi) == 1
1446
+ assert sin(4*o*pi) == 0
1447
+ assert tan(4*o*pi) == 0
1448
+ assert cot(4*o*pi) is zoo
1449
+
1450
+ assert cos(3*o*pi) == -1
1451
+ assert sin(3*o*pi) == 0
1452
+ assert tan(3*o*pi) == 0
1453
+ assert cot(3*o*pi) is zoo
1454
+
1455
+ assert cos(4.0*o*pi) == 1
1456
+ assert sin(4.0*o*pi) == 0
1457
+ assert tan(4.0*o*pi) == 0
1458
+ assert cot(4.0*o*pi) is zoo
1459
+
1460
+ assert cos(3.0*o*pi) == -1
1461
+ assert sin(3.0*o*pi) == 0
1462
+ assert tan(3.0*o*pi) == 0
1463
+ assert cot(3.0*o*pi) is zoo
1464
+
1465
+ assert cos(4.5*o*pi) == cos(0.5*pi*o)
1466
+ assert sin(4.5*o*pi) == sin(0.5*pi*o)
1467
+ assert tan(4.5*o*pi) == tan(0.5*pi*o)
1468
+ assert cot(4.5*o*pi) == cot(0.5*pi*o)
1469
+
1470
+ # x could be imaginary
1471
+ assert cos(4*x*pi) == cos(4*pi*x)
1472
+ assert sin(4*x*pi) == sin(4*pi*x)
1473
+ assert tan(4*x*pi) == tan(4*pi*x)
1474
+ assert cot(4*x*pi) == cot(4*pi*x)
1475
+
1476
+ assert cos(3*x*pi) == cos(3*pi*x)
1477
+ assert sin(3*x*pi) == sin(3*pi*x)
1478
+ assert tan(3*x*pi) == tan(3*pi*x)
1479
+ assert cot(3*x*pi) == cot(3*pi*x)
1480
+
1481
+ assert cos(4.0*x*pi) == cos(4.0*pi*x)
1482
+ assert sin(4.0*x*pi) == sin(4.0*pi*x)
1483
+ assert tan(4.0*x*pi) == tan(4.0*pi*x)
1484
+ assert cot(4.0*x*pi) == cot(4.0*pi*x)
1485
+
1486
+ assert cos(3.0*x*pi) == cos(3.0*pi*x)
1487
+ assert sin(3.0*x*pi) == sin(3.0*pi*x)
1488
+ assert tan(3.0*x*pi) == tan(3.0*pi*x)
1489
+ assert cot(3.0*x*pi) == cot(3.0*pi*x)
1490
+
1491
+ assert cos(4.5*x*pi) == cos(4.5*pi*x)
1492
+ assert sin(4.5*x*pi) == sin(4.5*pi*x)
1493
+ assert tan(4.5*x*pi) == tan(4.5*pi*x)
1494
+ assert cot(4.5*x*pi) == cot(4.5*pi*x)
1495
+
1496
+
1497
+ def test_inverses():
1498
+ raises(AttributeError, lambda: sin(x).inverse())
1499
+ raises(AttributeError, lambda: cos(x).inverse())
1500
+ assert tan(x).inverse() == atan
1501
+ assert cot(x).inverse() == acot
1502
+ raises(AttributeError, lambda: csc(x).inverse())
1503
+ raises(AttributeError, lambda: sec(x).inverse())
1504
+ assert asin(x).inverse() == sin
1505
+ assert acos(x).inverse() == cos
1506
+ assert atan(x).inverse() == tan
1507
+ assert acot(x).inverse() == cot
1508
+
1509
+
1510
+ def test_real_imag():
1511
+ a, b = symbols('a b', real=True)
1512
+ z = a + b*I
1513
+ for deep in [True, False]:
1514
+ assert sin(
1515
+ z).as_real_imag(deep=deep) == (sin(a)*cosh(b), cos(a)*sinh(b))
1516
+ assert cos(
1517
+ z).as_real_imag(deep=deep) == (cos(a)*cosh(b), -sin(a)*sinh(b))
1518
+ assert tan(z).as_real_imag(deep=deep) == (sin(2*a)/(cos(2*a) +
1519
+ cosh(2*b)), sinh(2*b)/(cos(2*a) + cosh(2*b)))
1520
+ assert cot(z).as_real_imag(deep=deep) == (-sin(2*a)/(cos(2*a) -
1521
+ cosh(2*b)), sinh(2*b)/(cos(2*a) - cosh(2*b)))
1522
+ assert sin(a).as_real_imag(deep=deep) == (sin(a), 0)
1523
+ assert cos(a).as_real_imag(deep=deep) == (cos(a), 0)
1524
+ assert tan(a).as_real_imag(deep=deep) == (tan(a), 0)
1525
+ assert cot(a).as_real_imag(deep=deep) == (cot(a), 0)
1526
+
1527
+
1528
+ @XFAIL
1529
+ def test_sin_cos_with_infinity():
1530
+ # Test for issue 5196
1531
+ # https://github.com/sympy/sympy/issues/5196
1532
+ assert sin(oo) is S.NaN
1533
+ assert cos(oo) is S.NaN
1534
+
1535
+
1536
+ @slow
1537
+ def test_sincos_rewrite_sqrt():
1538
+ # equivalent to testing rewrite(pow)
1539
+ for p in [1, 3, 5, 17]:
1540
+ for t in [1, 8]:
1541
+ n = t*p
1542
+ # The vertices `exp(i*pi/n)` of a regular `n`-gon can
1543
+ # be expressed by means of nested square roots if and
1544
+ # only if `n` is a product of Fermat primes, `p`, and
1545
+ # powers of 2, `t'. The code aims to check all vertices
1546
+ # not belonging to an `m`-gon for `m < n`(`gcd(i, n) == 1`).
1547
+ # For large `n` this makes the test too slow, therefore
1548
+ # the vertices are limited to those of index `i < 10`.
1549
+ for i in range(1, min((n + 1)//2 + 1, 10)):
1550
+ if 1 == gcd(i, n):
1551
+ x = i*pi/n
1552
+ s1 = sin(x).rewrite(sqrt)
1553
+ c1 = cos(x).rewrite(sqrt)
1554
+ assert not s1.has(cos, sin), "fails for %d*pi/%d" % (i, n)
1555
+ assert not c1.has(cos, sin), "fails for %d*pi/%d" % (i, n)
1556
+ assert 1e-3 > abs(sin(x.evalf(5)) - s1.evalf(2)), "fails for %d*pi/%d" % (i, n)
1557
+ assert 1e-3 > abs(cos(x.evalf(5)) - c1.evalf(2)), "fails for %d*pi/%d" % (i, n)
1558
+ assert cos(pi/14).rewrite(sqrt) == sqrt(cos(pi/7)/2 + S.Half)
1559
+ assert cos(pi*Rational(-15, 2)/11, evaluate=False).rewrite(
1560
+ sqrt) == -sqrt(-cos(pi*Rational(4, 11))/2 + S.Half)
1561
+ assert cos(Mul(2, pi, S.Half, evaluate=False), evaluate=False).rewrite(
1562
+ sqrt) == -1
1563
+ e = cos(pi/3/17) # don't use pi/15 since that is caught at instantiation
1564
+ a = (
1565
+ -3*sqrt(-sqrt(17) + 17)*sqrt(sqrt(17) + 17)/64 -
1566
+ 3*sqrt(34)*sqrt(sqrt(17) + 17)/128 - sqrt(sqrt(17) +
1567
+ 17)*sqrt(-8*sqrt(2)*sqrt(sqrt(17) + 17) - sqrt(2)*sqrt(-sqrt(17) + 17)
1568
+ + sqrt(34)*sqrt(-sqrt(17) + 17) + 6*sqrt(17) + 34)/64 - sqrt(-sqrt(17)
1569
+ + 17)*sqrt(-8*sqrt(2)*sqrt(sqrt(17) + 17) - sqrt(2)*sqrt(-sqrt(17) +
1570
+ 17) + sqrt(34)*sqrt(-sqrt(17) + 17) + 6*sqrt(17) + 34)/128 - Rational(1, 32) +
1571
+ sqrt(2)*sqrt(-8*sqrt(2)*sqrt(sqrt(17) + 17) - sqrt(2)*sqrt(-sqrt(17) +
1572
+ 17) + sqrt(34)*sqrt(-sqrt(17) + 17) + 6*sqrt(17) + 34)/64 +
1573
+ 3*sqrt(2)*sqrt(sqrt(17) + 17)/128 + sqrt(34)*sqrt(-sqrt(17) + 17)/128
1574
+ + 13*sqrt(2)*sqrt(-sqrt(17) + 17)/128 + sqrt(17)*sqrt(-sqrt(17) +
1575
+ 17)*sqrt(-8*sqrt(2)*sqrt(sqrt(17) + 17) - sqrt(2)*sqrt(-sqrt(17) + 17)
1576
+ + sqrt(34)*sqrt(-sqrt(17) + 17) + 6*sqrt(17) + 34)/128 + 5*sqrt(17)/32
1577
+ + sqrt(3)*sqrt(-sqrt(2)*sqrt(sqrt(17) + 17)*sqrt(sqrt(17)/32 +
1578
+ sqrt(2)*sqrt(-sqrt(17) + 17)/32 +
1579
+ sqrt(2)*sqrt(-8*sqrt(2)*sqrt(sqrt(17) + 17) - sqrt(2)*sqrt(-sqrt(17) +
1580
+ 17) + sqrt(34)*sqrt(-sqrt(17) + 17) + 6*sqrt(17) + 34)/32 + Rational(15, 32))/8 -
1581
+ 5*sqrt(2)*sqrt(sqrt(17)/32 + sqrt(2)*sqrt(-sqrt(17) + 17)/32 +
1582
+ sqrt(2)*sqrt(-8*sqrt(2)*sqrt(sqrt(17) + 17) - sqrt(2)*sqrt(-sqrt(17) +
1583
+ 17) + sqrt(34)*sqrt(-sqrt(17) + 17) + 6*sqrt(17) + 34)/32 +
1584
+ Rational(15, 32))*sqrt(-8*sqrt(2)*sqrt(sqrt(17) + 17) - sqrt(2)*sqrt(-sqrt(17) +
1585
+ 17) + sqrt(34)*sqrt(-sqrt(17) + 17) + 6*sqrt(17) + 34)/64 -
1586
+ 3*sqrt(2)*sqrt(-sqrt(17) + 17)*sqrt(sqrt(17)/32 +
1587
+ sqrt(2)*sqrt(-sqrt(17) + 17)/32 +
1588
+ sqrt(2)*sqrt(-8*sqrt(2)*sqrt(sqrt(17) + 17) - sqrt(2)*sqrt(-sqrt(17) +
1589
+ 17) + sqrt(34)*sqrt(-sqrt(17) + 17) + 6*sqrt(17) + 34)/32 + Rational(15, 32))/32
1590
+ + sqrt(34)*sqrt(sqrt(17)/32 + sqrt(2)*sqrt(-sqrt(17) + 17)/32 +
1591
+ sqrt(2)*sqrt(-8*sqrt(2)*sqrt(sqrt(17) + 17) - sqrt(2)*sqrt(-sqrt(17) +
1592
+ 17) + sqrt(34)*sqrt(-sqrt(17) + 17) + 6*sqrt(17) + 34)/32 +
1593
+ Rational(15, 32))*sqrt(-8*sqrt(2)*sqrt(sqrt(17) + 17) - sqrt(2)*sqrt(-sqrt(17) +
1594
+ 17) + sqrt(34)*sqrt(-sqrt(17) + 17) + 6*sqrt(17) + 34)/64 +
1595
+ sqrt(sqrt(17)/32 + sqrt(2)*sqrt(-sqrt(17) + 17)/32 +
1596
+ sqrt(2)*sqrt(-8*sqrt(2)*sqrt(sqrt(17) + 17) - sqrt(2)*sqrt(-sqrt(17) +
1597
+ 17) + sqrt(34)*sqrt(-sqrt(17) + 17) + 6*sqrt(17) + 34)/32 + Rational(15, 32))/2 +
1598
+ S.Half + sqrt(-sqrt(17) + 17)*sqrt(sqrt(17)/32 + sqrt(2)*sqrt(-sqrt(17) +
1599
+ 17)/32 + sqrt(2)*sqrt(-8*sqrt(2)*sqrt(sqrt(17) + 17) -
1600
+ sqrt(2)*sqrt(-sqrt(17) + 17) + sqrt(34)*sqrt(-sqrt(17) + 17) +
1601
+ 6*sqrt(17) + 34)/32 + Rational(15, 32))*sqrt(-8*sqrt(2)*sqrt(sqrt(17) + 17) -
1602
+ sqrt(2)*sqrt(-sqrt(17) + 17) + sqrt(34)*sqrt(-sqrt(17) + 17) +
1603
+ 6*sqrt(17) + 34)/32 + sqrt(34)*sqrt(-sqrt(17) + 17)*sqrt(sqrt(17)/32 +
1604
+ sqrt(2)*sqrt(-sqrt(17) + 17)/32 +
1605
+ sqrt(2)*sqrt(-8*sqrt(2)*sqrt(sqrt(17) + 17) - sqrt(2)*sqrt(-sqrt(17) +
1606
+ 17) + sqrt(34)*sqrt(-sqrt(17) + 17) + 6*sqrt(17) + 34)/32 +
1607
+ Rational(15, 32))/32)/2)
1608
+ assert e.rewrite(sqrt) == a
1609
+ assert e.n() == a.n()
1610
+ # coverage of fermatCoords: multiplicity > 1; the following could be
1611
+ # different but that portion of the code should be tested in some way
1612
+ assert cos(pi/9/17).rewrite(sqrt) == \
1613
+ sin(pi/9)*sin(pi*Rational(2, 17)) + cos(pi/9)*cos(pi*Rational(2, 17))
1614
+
1615
+
1616
+ @slow
1617
+ def test_sincos_rewrite_sqrt_257():
1618
+ assert cos(pi/257).rewrite(sqrt).evalf(64) == cos(pi/257).evalf(64)
1619
+
1620
+
1621
+ @slow
1622
+ def test_tancot_rewrite_sqrt():
1623
+ # equivalent to testing rewrite(pow)
1624
+ for p in [1, 3, 5, 17]:
1625
+ for t in [1, 8]:
1626
+ n = t*p
1627
+ for i in range(1, min((n + 1)//2 + 1, 10)):
1628
+ if 1 == gcd(i, n):
1629
+ x = i*pi/n
1630
+ if 2*i != n and 3*i != 2*n:
1631
+ t1 = tan(x).rewrite(sqrt)
1632
+ assert not t1.has(cot, tan), "fails for %d*pi/%d" % (i, n)
1633
+ assert 1e-3 > abs( tan(x.evalf(7)) - t1.evalf(4) ), "fails for %d*pi/%d" % (i, n)
1634
+ if i != 0 and i != n:
1635
+ c1 = cot(x).rewrite(sqrt)
1636
+ assert not c1.has(cot, tan), "fails for %d*pi/%d" % (i, n)
1637
+ assert 1e-3 > abs( cot(x.evalf(7)) - c1.evalf(4) ), "fails for %d*pi/%d" % (i, n)
1638
+
1639
+
1640
+ def test_sec():
1641
+ x = symbols('x', real=True)
1642
+ z = symbols('z')
1643
+
1644
+ assert sec.nargs == FiniteSet(1)
1645
+
1646
+ assert sec(zoo) is nan
1647
+ assert sec(0) == 1
1648
+ assert sec(pi) == -1
1649
+ assert sec(pi/2) is zoo
1650
+ assert sec(-pi/2) is zoo
1651
+ assert sec(pi/6) == 2*sqrt(3)/3
1652
+ assert sec(pi/3) == 2
1653
+ assert sec(pi*Rational(5, 2)) is zoo
1654
+ assert sec(pi*Rational(9, 7)) == -sec(pi*Rational(2, 7))
1655
+ assert sec(pi*Rational(3, 4)) == -sqrt(2) # issue 8421
1656
+ assert sec(I) == 1/cosh(1)
1657
+ assert sec(x*I) == 1/cosh(x)
1658
+ assert sec(-x) == sec(x)
1659
+
1660
+ assert sec(asec(x)) == x
1661
+
1662
+ assert sec(z).conjugate() == sec(conjugate(z))
1663
+
1664
+ assert (sec(z).as_real_imag() ==
1665
+ (cos(re(z))*cosh(im(z))/(sin(re(z))**2*sinh(im(z))**2 +
1666
+ cos(re(z))**2*cosh(im(z))**2),
1667
+ sin(re(z))*sinh(im(z))/(sin(re(z))**2*sinh(im(z))**2 +
1668
+ cos(re(z))**2*cosh(im(z))**2)))
1669
+
1670
+ assert sec(x).expand(trig=True) == 1/cos(x)
1671
+ assert sec(2*x).expand(trig=True) == 1/(2*cos(x)**2 - 1)
1672
+
1673
+ assert sec(x).is_extended_real == True
1674
+ assert sec(z).is_real == None
1675
+
1676
+ assert sec(a).is_algebraic is None
1677
+ assert sec(na).is_algebraic is False
1678
+
1679
+ assert sec(x).as_leading_term() == sec(x)
1680
+
1681
+ assert sec(0, evaluate=False).is_finite == True
1682
+ assert sec(x).is_finite == None
1683
+ assert sec(pi/2, evaluate=False).is_finite == False
1684
+
1685
+ assert series(sec(x), x, x0=0, n=6) == 1 + x**2/2 + 5*x**4/24 + O(x**6)
1686
+
1687
+ # https://github.com/sympy/sympy/issues/7166
1688
+ assert series(sqrt(sec(x))) == 1 + x**2/4 + 7*x**4/96 + O(x**6)
1689
+
1690
+ # https://github.com/sympy/sympy/issues/7167
1691
+ assert (series(sqrt(sec(x)), x, x0=pi*3/2, n=4) ==
1692
+ 1/sqrt(x - pi*Rational(3, 2)) + (x - pi*Rational(3, 2))**Rational(3, 2)/12 +
1693
+ (x - pi*Rational(3, 2))**Rational(7, 2)/160 + O((x - pi*Rational(3, 2))**4, (x, pi*Rational(3, 2))))
1694
+
1695
+ assert sec(x).diff(x) == tan(x)*sec(x)
1696
+
1697
+ # Taylor Term checks
1698
+ assert sec(z).taylor_term(4, z) == 5*z**4/24
1699
+ assert sec(z).taylor_term(6, z) == 61*z**6/720
1700
+ assert sec(z).taylor_term(5, z) == 0
1701
+
1702
+
1703
+ def test_sec_rewrite():
1704
+ assert sec(x).rewrite(exp) == 1/(exp(I*x)/2 + exp(-I*x)/2)
1705
+ assert sec(x).rewrite(cos) == 1/cos(x)
1706
+ assert sec(x).rewrite(tan) == (tan(x/2)**2 + 1)/(-tan(x/2)**2 + 1)
1707
+ assert sec(x).rewrite(pow) == sec(x)
1708
+ assert sec(x).rewrite(sqrt) == sec(x)
1709
+ assert sec(z).rewrite(cot) == (cot(z/2)**2 + 1)/(cot(z/2)**2 - 1)
1710
+ assert sec(x).rewrite(sin) == 1 / sin(x + pi / 2, evaluate=False)
1711
+ assert sec(x).rewrite(tan) == (tan(x / 2)**2 + 1) / (-tan(x / 2)**2 + 1)
1712
+ assert sec(x).rewrite(csc) == csc(-x + pi/2, evaluate=False)
1713
+
1714
+
1715
+ def test_sec_fdiff():
1716
+ assert sec(x).fdiff() == tan(x)*sec(x)
1717
+ raises(ArgumentIndexError, lambda: sec(x).fdiff(2))
1718
+
1719
+
1720
+ def test_csc():
1721
+ x = symbols('x', real=True)
1722
+ z = symbols('z')
1723
+
1724
+ # https://github.com/sympy/sympy/issues/6707
1725
+ cosecant = csc('x')
1726
+ alternate = 1/sin('x')
1727
+ assert cosecant.equals(alternate) == True
1728
+ assert alternate.equals(cosecant) == True
1729
+
1730
+ assert csc.nargs == FiniteSet(1)
1731
+
1732
+ assert csc(0) is zoo
1733
+ assert csc(pi) is zoo
1734
+ assert csc(zoo) is nan
1735
+
1736
+ assert csc(pi/2) == 1
1737
+ assert csc(-pi/2) == -1
1738
+ assert csc(pi/6) == 2
1739
+ assert csc(pi/3) == 2*sqrt(3)/3
1740
+ assert csc(pi*Rational(5, 2)) == 1
1741
+ assert csc(pi*Rational(9, 7)) == -csc(pi*Rational(2, 7))
1742
+ assert csc(pi*Rational(3, 4)) == sqrt(2) # issue 8421
1743
+ assert csc(I) == -I/sinh(1)
1744
+ assert csc(x*I) == -I/sinh(x)
1745
+ assert csc(-x) == -csc(x)
1746
+
1747
+ assert csc(acsc(x)) == x
1748
+
1749
+ assert csc(z).conjugate() == csc(conjugate(z))
1750
+
1751
+ assert (csc(z).as_real_imag() ==
1752
+ (sin(re(z))*cosh(im(z))/(sin(re(z))**2*cosh(im(z))**2 +
1753
+ cos(re(z))**2*sinh(im(z))**2),
1754
+ -cos(re(z))*sinh(im(z))/(sin(re(z))**2*cosh(im(z))**2 +
1755
+ cos(re(z))**2*sinh(im(z))**2)))
1756
+
1757
+ assert csc(x).expand(trig=True) == 1/sin(x)
1758
+ assert csc(2*x).expand(trig=True) == 1/(2*sin(x)*cos(x))
1759
+
1760
+ assert csc(x).is_extended_real == True
1761
+ assert csc(z).is_real == None
1762
+
1763
+ assert csc(a).is_algebraic is None
1764
+ assert csc(na).is_algebraic is False
1765
+
1766
+ assert csc(x).as_leading_term() == csc(x)
1767
+
1768
+ assert csc(0, evaluate=False).is_finite == False
1769
+ assert csc(x).is_finite == None
1770
+ assert csc(pi/2, evaluate=False).is_finite == True
1771
+
1772
+ assert series(csc(x), x, x0=pi/2, n=6) == \
1773
+ 1 + (x - pi/2)**2/2 + 5*(x - pi/2)**4/24 + O((x - pi/2)**6, (x, pi/2))
1774
+ assert series(csc(x), x, x0=0, n=6) == \
1775
+ 1/x + x/6 + 7*x**3/360 + 31*x**5/15120 + O(x**6)
1776
+
1777
+ assert csc(x).diff(x) == -cot(x)*csc(x)
1778
+
1779
+ assert csc(x).taylor_term(2, x) == 0
1780
+ assert csc(x).taylor_term(3, x) == 7*x**3/360
1781
+ assert csc(x).taylor_term(5, x) == 31*x**5/15120
1782
+ raises(ArgumentIndexError, lambda: csc(x).fdiff(2))
1783
+
1784
+
1785
+ def test_asec():
1786
+ z = Symbol('z', zero=True)
1787
+ assert asec(z) is zoo
1788
+ assert asec(nan) is nan
1789
+ assert asec(1) == 0
1790
+ assert asec(-1) == pi
1791
+ assert asec(oo) == pi/2
1792
+ assert asec(-oo) == pi/2
1793
+ assert asec(zoo) == pi/2
1794
+
1795
+ assert asec(sec(pi*Rational(13, 4))) == pi*Rational(3, 4)
1796
+ assert asec(1 + sqrt(5)) == pi*Rational(2, 5)
1797
+ assert asec(2/sqrt(3)) == pi/6
1798
+ assert asec(sqrt(4 - 2*sqrt(2))) == pi/8
1799
+ assert asec(-sqrt(4 + 2*sqrt(2))) == pi*Rational(5, 8)
1800
+ assert asec(sqrt(2 + 2*sqrt(5)/5)) == pi*Rational(3, 10)
1801
+ assert asec(-sqrt(2 + 2*sqrt(5)/5)) == pi*Rational(7, 10)
1802
+ assert asec(sqrt(2) - sqrt(6)) == pi*Rational(11, 12)
1803
+
1804
+ assert asec(x).diff(x) == 1/(x**2*sqrt(1 - 1/x**2))
1805
+
1806
+ assert asec(x).rewrite(log) == I*log(sqrt(1 - 1/x**2) + I/x) + pi/2
1807
+ assert asec(x).rewrite(asin) == -asin(1/x) + pi/2
1808
+ assert asec(x).rewrite(acos) == acos(1/x)
1809
+ assert asec(x).rewrite(atan) == \
1810
+ pi*(1 - sqrt(x**2)/x)/2 + sqrt(x**2)*atan(sqrt(x**2 - 1))/x
1811
+ assert asec(x).rewrite(acot) == \
1812
+ pi*(1 - sqrt(x**2)/x)/2 + sqrt(x**2)*acot(1/sqrt(x**2 - 1))/x
1813
+ assert asec(x).rewrite(acsc) == -acsc(x) + pi/2
1814
+ raises(ArgumentIndexError, lambda: asec(x).fdiff(2))
1815
+
1816
+
1817
+ def test_asec_is_real():
1818
+ assert asec(S.Half).is_real is False
1819
+ n = Symbol('n', positive=True, integer=True)
1820
+ assert asec(n).is_extended_real is True
1821
+ assert asec(x).is_real is None
1822
+ assert asec(r).is_real is None
1823
+ t = Symbol('t', real=False, finite=True)
1824
+ assert asec(t).is_real is False
1825
+
1826
+
1827
+ def test_asec_leading_term():
1828
+ assert asec(1/x).as_leading_term(x) == pi/2
1829
+ # Tests concerning branch points
1830
+ assert asec(x + 1).as_leading_term(x) == sqrt(2)*sqrt(x)
1831
+ assert asec(x - 1).as_leading_term(x) == pi
1832
+ # Tests concerning points lying on branch cuts
1833
+ assert asec(x).as_leading_term(x, cdir=1) == -I*log(x) + I*log(2)
1834
+ assert asec(x).as_leading_term(x, cdir=-1) == I*log(x) + 2*pi - I*log(2)
1835
+ assert asec(I*x + 1/2).as_leading_term(x, cdir=1) == asec(1/2)
1836
+ assert asec(-I*x + 1/2).as_leading_term(x, cdir=1) == -asec(1/2)
1837
+ assert asec(I*x - 1/2).as_leading_term(x, cdir=1) == 2*pi - asec(-1/2)
1838
+ assert asec(-I*x - 1/2).as_leading_term(x, cdir=1) == asec(-1/2)
1839
+ # Tests concerning im(ndir) == 0
1840
+ assert asec(-I*x**2 + x - S(1)/2).as_leading_term(x, cdir=1) == pi + I*log(2 - sqrt(3))
1841
+ assert asec(-I*x**2 + x - S(1)/2).as_leading_term(x, cdir=-1) == pi + I*log(2 - sqrt(3))
1842
+
1843
+
1844
+ def test_asec_series():
1845
+ assert asec(x).series(x, 0, 9) == \
1846
+ I*log(2) - I*log(x) - I*x**2/4 - 3*I*x**4/32 \
1847
+ - 5*I*x**6/96 - 35*I*x**8/1024 + O(x**9)
1848
+ t4 = asec(x).taylor_term(4, x)
1849
+ assert t4 == -3*I*x**4/32
1850
+ assert asec(x).taylor_term(6, x, t4, 0) == -5*I*x**6/96
1851
+
1852
+
1853
+ def test_acsc():
1854
+ assert acsc(nan) is nan
1855
+ assert acsc(1) == pi/2
1856
+ assert acsc(-1) == -pi/2
1857
+ assert acsc(oo) == 0
1858
+ assert acsc(-oo) == 0
1859
+ assert acsc(zoo) == 0
1860
+ assert acsc(0) is zoo
1861
+
1862
+ assert acsc(csc(3)) == -3 + pi
1863
+ assert acsc(csc(4)) == -4 + pi
1864
+ assert acsc(csc(6)) == 6 - 2*pi
1865
+ assert unchanged(acsc, csc(x))
1866
+ assert unchanged(acsc, sec(x))
1867
+
1868
+ assert acsc(2/sqrt(3)) == pi/3
1869
+ assert acsc(csc(pi*Rational(13, 4))) == -pi/4
1870
+ assert acsc(sqrt(2 + 2*sqrt(5)/5)) == pi/5
1871
+ assert acsc(-sqrt(2 + 2*sqrt(5)/5)) == -pi/5
1872
+ assert acsc(-2) == -pi/6
1873
+ assert acsc(-sqrt(4 + 2*sqrt(2))) == -pi/8
1874
+ assert acsc(sqrt(4 - 2*sqrt(2))) == pi*Rational(3, 8)
1875
+ assert acsc(1 + sqrt(5)) == pi/10
1876
+ assert acsc(sqrt(2) - sqrt(6)) == pi*Rational(-5, 12)
1877
+
1878
+ assert acsc(x).diff(x) == -1/(x**2*sqrt(1 - 1/x**2))
1879
+
1880
+ assert acsc(x).rewrite(log) == -I*log(sqrt(1 - 1/x**2) + I/x)
1881
+ assert acsc(x).rewrite(asin) == asin(1/x)
1882
+ assert acsc(x).rewrite(acos) == -acos(1/x) + pi/2
1883
+ assert acsc(x).rewrite(atan) == \
1884
+ (-atan(sqrt(x**2 - 1)) + pi/2)*sqrt(x**2)/x
1885
+ assert acsc(x).rewrite(acot) == (-acot(1/sqrt(x**2 - 1)) + pi/2)*sqrt(x**2)/x
1886
+ assert acsc(x).rewrite(asec) == -asec(x) + pi/2
1887
+ raises(ArgumentIndexError, lambda: acsc(x).fdiff(2))
1888
+
1889
+
1890
+ def test_csc_rewrite():
1891
+ assert csc(x).rewrite(pow) == csc(x)
1892
+ assert csc(x).rewrite(sqrt) == csc(x)
1893
+
1894
+ assert csc(x).rewrite(exp) == 2*I/(exp(I*x) - exp(-I*x))
1895
+ assert csc(x).rewrite(sin) == 1/sin(x)
1896
+ assert csc(x).rewrite(tan) == (tan(x/2)**2 + 1)/(2*tan(x/2))
1897
+ assert csc(x).rewrite(cot) == (cot(x/2)**2 + 1)/(2*cot(x/2))
1898
+ assert csc(x).rewrite(cos) == 1/cos(x - pi/2, evaluate=False)
1899
+ assert csc(x).rewrite(sec) == sec(-x + pi/2, evaluate=False)
1900
+
1901
+ # issue 17349
1902
+ assert csc(1 - exp(-besselj(I, I))).rewrite(cos) == \
1903
+ -1/cos(-pi/2 - 1 + cos(I*besselj(I, I)) +
1904
+ I*cos(-pi/2 + I*besselj(I, I), evaluate=False), evaluate=False)
1905
+
1906
+
1907
+ def test_acsc_leading_term():
1908
+ assert acsc(1/x).as_leading_term(x) == x
1909
+ # Tests concerning branch points
1910
+ assert acsc(x + 1).as_leading_term(x) == pi/2
1911
+ assert acsc(x - 1).as_leading_term(x) == -pi/2
1912
+ # Tests concerning points lying on branch cuts
1913
+ assert acsc(x).as_leading_term(x, cdir=1) == I*log(x) + pi/2 - I*log(2)
1914
+ assert acsc(x).as_leading_term(x, cdir=-1) == -I*log(x) - 3*pi/2 + I*log(2)
1915
+ assert acsc(I*x + 1/2).as_leading_term(x, cdir=1) == acsc(1/2)
1916
+ assert acsc(-I*x + 1/2).as_leading_term(x, cdir=1) == pi - acsc(1/2)
1917
+ assert acsc(I*x - 1/2).as_leading_term(x, cdir=1) == -pi - acsc(-1/2)
1918
+ assert acsc(-I*x - 1/2).as_leading_term(x, cdir=1) == -acsc(1/2)
1919
+ # Tests concerning im(ndir) == 0
1920
+ assert acsc(-I*x**2 + x - S(1)/2).as_leading_term(x, cdir=1) == -pi/2 + I*log(sqrt(3) + 2)
1921
+ assert acsc(-I*x**2 + x - S(1)/2).as_leading_term(x, cdir=-1) == -pi/2 + I*log(sqrt(3) + 2)
1922
+
1923
+
1924
+ def test_acsc_series():
1925
+ assert acsc(x).series(x, 0, 9) == \
1926
+ -I*log(2) + pi/2 + I*log(x) + I*x**2/4 \
1927
+ + 3*I*x**4/32 + 5*I*x**6/96 + 35*I*x**8/1024 + O(x**9)
1928
+ t6 = acsc(x).taylor_term(6, x)
1929
+ assert t6 == 5*I*x**6/96
1930
+ assert acsc(x).taylor_term(8, x, t6, 0) == 35*I*x**8/1024
1931
+
1932
+
1933
+ def test_asin_nseries():
1934
+ assert asin(x + 2)._eval_nseries(x, 4, None, I) == -asin(2) + pi + \
1935
+ sqrt(3)*I*x/3 - sqrt(3)*I*x**2/9 + sqrt(3)*I*x**3/18 + O(x**4)
1936
+ assert asin(x + 2)._eval_nseries(x, 4, None, -I) == asin(2) - \
1937
+ sqrt(3)*I*x/3 + sqrt(3)*I*x**2/9 - sqrt(3)*I*x**3/18 + O(x**4)
1938
+ assert asin(x - 2)._eval_nseries(x, 4, None, I) == -asin(2) - \
1939
+ sqrt(3)*I*x/3 - sqrt(3)*I*x**2/9 - sqrt(3)*I*x**3/18 + O(x**4)
1940
+ assert asin(x - 2)._eval_nseries(x, 4, None, -I) == asin(2) - pi + \
1941
+ sqrt(3)*I*x/3 + sqrt(3)*I*x**2/9 + sqrt(3)*I*x**3/18 + O(x**4)
1942
+ # testing nseries for asin at branch points
1943
+ assert asin(1 + x)._eval_nseries(x, 3, None) == pi/2 - sqrt(2)*sqrt(-x) - \
1944
+ sqrt(2)*(-x)**(S(3)/2)/12 - 3*sqrt(2)*(-x)**(S(5)/2)/160 + O(x**3)
1945
+ assert asin(-1 + x)._eval_nseries(x, 3, None) == -pi/2 + sqrt(2)*sqrt(x) + \
1946
+ sqrt(2)*x**(S(3)/2)/12 + 3*sqrt(2)*x**(S(5)/2)/160 + O(x**3)
1947
+ assert asin(exp(x))._eval_nseries(x, 3, None) == pi/2 - sqrt(2)*sqrt(-x) + \
1948
+ sqrt(2)*(-x)**(S(3)/2)/6 - sqrt(2)*(-x)**(S(5)/2)/120 + O(x**3)
1949
+ assert asin(-exp(x))._eval_nseries(x, 3, None) == -pi/2 + sqrt(2)*sqrt(-x) - \
1950
+ sqrt(2)*(-x)**(S(3)/2)/6 + sqrt(2)*(-x)**(S(5)/2)/120 + O(x**3)
1951
+
1952
+
1953
+ def test_acos_nseries():
1954
+ assert acos(x + 2)._eval_nseries(x, 4, None, I) == -acos(2) - sqrt(3)*I*x/3 + \
1955
+ sqrt(3)*I*x**2/9 - sqrt(3)*I*x**3/18 + O(x**4)
1956
+ assert acos(x + 2)._eval_nseries(x, 4, None, -I) == acos(2) + sqrt(3)*I*x/3 - \
1957
+ sqrt(3)*I*x**2/9 + sqrt(3)*I*x**3/18 + O(x**4)
1958
+ assert acos(x - 2)._eval_nseries(x, 4, None, I) == acos(-2) + sqrt(3)*I*x/3 + \
1959
+ sqrt(3)*I*x**2/9 + sqrt(3)*I*x**3/18 + O(x**4)
1960
+ assert acos(x - 2)._eval_nseries(x, 4, None, -I) == -acos(-2) + 2*pi - \
1961
+ sqrt(3)*I*x/3 - sqrt(3)*I*x**2/9 - sqrt(3)*I*x**3/18 + O(x**4)
1962
+ # testing nseries for acos at branch points
1963
+ assert acos(1 + x)._eval_nseries(x, 3, None) == sqrt(2)*sqrt(-x) + \
1964
+ sqrt(2)*(-x)**(S(3)/2)/12 + 3*sqrt(2)*(-x)**(S(5)/2)/160 + O(x**3)
1965
+ assert acos(-1 + x)._eval_nseries(x, 3, None) == pi - sqrt(2)*sqrt(x) - \
1966
+ sqrt(2)*x**(S(3)/2)/12 - 3*sqrt(2)*x**(S(5)/2)/160 + O(x**3)
1967
+ assert acos(exp(x))._eval_nseries(x, 3, None) == sqrt(2)*sqrt(-x) - \
1968
+ sqrt(2)*(-x)**(S(3)/2)/6 + sqrt(2)*(-x)**(S(5)/2)/120 + O(x**3)
1969
+ assert acos(-exp(x))._eval_nseries(x, 3, None) == pi - sqrt(2)*sqrt(-x) + \
1970
+ sqrt(2)*(-x)**(S(3)/2)/6 - sqrt(2)*(-x)**(S(5)/2)/120 + O(x**3)
1971
+
1972
+
1973
+ def test_atan_nseries():
1974
+ assert atan(x + 2*I)._eval_nseries(x, 4, None, 1) == I*atanh(2) - x/3 - \
1975
+ 2*I*x**2/9 + 13*x**3/81 + O(x**4)
1976
+ assert atan(x + 2*I)._eval_nseries(x, 4, None, -1) == I*atanh(2) - pi - \
1977
+ x/3 - 2*I*x**2/9 + 13*x**3/81 + O(x**4)
1978
+ assert atan(x - 2*I)._eval_nseries(x, 4, None, 1) == -I*atanh(2) + pi - \
1979
+ x/3 + 2*I*x**2/9 + 13*x**3/81 + O(x**4)
1980
+ assert atan(x - 2*I)._eval_nseries(x, 4, None, -1) == -I*atanh(2) - x/3 + \
1981
+ 2*I*x**2/9 + 13*x**3/81 + O(x**4)
1982
+ assert atan(1/x)._eval_nseries(x, 2, None, 1) == pi/2 - x + O(x**2)
1983
+ assert atan(1/x)._eval_nseries(x, 2, None, -1) == -pi/2 - x + O(x**2)
1984
+ # testing nseries for atan at branch points
1985
+ assert atan(x + I)._eval_nseries(x, 4, None) == I*log(2)/2 + pi/4 - \
1986
+ I*log(x)/2 + x/4 + I*x**2/16 - x**3/48 + O(x**4)
1987
+ assert atan(x - I)._eval_nseries(x, 4, None) == -I*log(2)/2 + pi/4 + \
1988
+ I*log(x)/2 + x/4 - I*x**2/16 - x**3/48 + O(x**4)
1989
+
1990
+
1991
+ def test_acot_nseries():
1992
+ assert acot(x + S(1)/2*I)._eval_nseries(x, 4, None, 1) == -I*acoth(S(1)/2) + \
1993
+ pi - 4*x/3 + 8*I*x**2/9 + 112*x**3/81 + O(x**4)
1994
+ assert acot(x + S(1)/2*I)._eval_nseries(x, 4, None, -1) == -I*acoth(S(1)/2) - \
1995
+ 4*x/3 + 8*I*x**2/9 + 112*x**3/81 + O(x**4)
1996
+ assert acot(x - S(1)/2*I)._eval_nseries(x, 4, None, 1) == I*acoth(S(1)/2) - \
1997
+ 4*x/3 - 8*I*x**2/9 + 112*x**3/81 + O(x**4)
1998
+ assert acot(x - S(1)/2*I)._eval_nseries(x, 4, None, -1) == I*acoth(S(1)/2) - \
1999
+ pi - 4*x/3 - 8*I*x**2/9 + 112*x**3/81 + O(x**4)
2000
+ assert acot(x)._eval_nseries(x, 2, None, 1) == pi/2 - x + O(x**2)
2001
+ assert acot(x)._eval_nseries(x, 2, None, -1) == -pi/2 - x + O(x**2)
2002
+ # testing nseries for acot at branch points
2003
+ assert acot(x + I)._eval_nseries(x, 4, None) == -I*log(2)/2 + pi/4 + \
2004
+ I*log(x)/2 - x/4 - I*x**2/16 + x**3/48 + O(x**4)
2005
+ assert acot(x - I)._eval_nseries(x, 4, None) == I*log(2)/2 + pi/4 - \
2006
+ I*log(x)/2 - x/4 + I*x**2/16 + x**3/48 + O(x**4)
2007
+
2008
+
2009
+ def test_asec_nseries():
2010
+ assert asec(x + S(1)/2)._eval_nseries(x, 4, None, I) == asec(S(1)/2) - \
2011
+ 4*sqrt(3)*I*x/3 + 8*sqrt(3)*I*x**2/9 - 16*sqrt(3)*I*x**3/9 + O(x**4)
2012
+ assert asec(x + S(1)/2)._eval_nseries(x, 4, None, -I) == -asec(S(1)/2) + \
2013
+ 4*sqrt(3)*I*x/3 - 8*sqrt(3)*I*x**2/9 + 16*sqrt(3)*I*x**3/9 + O(x**4)
2014
+ assert asec(x - S(1)/2)._eval_nseries(x, 4, None, I) == -asec(-S(1)/2) + \
2015
+ 2*pi + 4*sqrt(3)*I*x/3 + 8*sqrt(3)*I*x**2/9 + 16*sqrt(3)*I*x**3/9 + O(x**4)
2016
+ assert asec(x - S(1)/2)._eval_nseries(x, 4, None, -I) == asec(-S(1)/2) - \
2017
+ 4*sqrt(3)*I*x/3 - 8*sqrt(3)*I*x**2/9 - 16*sqrt(3)*I*x**3/9 + O(x**4)
2018
+ # testing nseries for asec at branch points
2019
+ assert asec(1 + x)._eval_nseries(x, 3, None) == sqrt(2)*sqrt(x) - \
2020
+ 5*sqrt(2)*x**(S(3)/2)/12 + 43*sqrt(2)*x**(S(5)/2)/160 + O(x**3)
2021
+ assert asec(-1 + x)._eval_nseries(x, 3, None) == pi - sqrt(2)*sqrt(-x) + \
2022
+ 5*sqrt(2)*(-x)**(S(3)/2)/12 - 43*sqrt(2)*(-x)**(S(5)/2)/160 + O(x**3)
2023
+ assert asec(exp(x))._eval_nseries(x, 3, None) == sqrt(2)*sqrt(x) - \
2024
+ sqrt(2)*x**(S(3)/2)/6 + sqrt(2)*x**(S(5)/2)/120 + O(x**3)
2025
+ assert asec(-exp(x))._eval_nseries(x, 3, None) == pi - sqrt(2)*sqrt(x) + \
2026
+ sqrt(2)*x**(S(3)/2)/6 - sqrt(2)*x**(S(5)/2)/120 + O(x**3)
2027
+
2028
+
2029
+ def test_acsc_nseries():
2030
+ assert acsc(x + S(1)/2)._eval_nseries(x, 4, None, I) == acsc(S(1)/2) + \
2031
+ 4*sqrt(3)*I*x/3 - 8*sqrt(3)*I*x**2/9 + 16*sqrt(3)*I*x**3/9 + O(x**4)
2032
+ assert acsc(x + S(1)/2)._eval_nseries(x, 4, None, -I) == -acsc(S(1)/2) + \
2033
+ pi - 4*sqrt(3)*I*x/3 + 8*sqrt(3)*I*x**2/9 - 16*sqrt(3)*I*x**3/9 + O(x**4)
2034
+ assert acsc(x - S(1)/2)._eval_nseries(x, 4, None, I) == acsc(S(1)/2) - pi -\
2035
+ 4*sqrt(3)*I*x/3 - 8*sqrt(3)*I*x**2/9 - 16*sqrt(3)*I*x**3/9 + O(x**4)
2036
+ assert acsc(x - S(1)/2)._eval_nseries(x, 4, None, -I) == -acsc(S(1)/2) + \
2037
+ 4*sqrt(3)*I*x/3 + 8*sqrt(3)*I*x**2/9 + 16*sqrt(3)*I*x**3/9 + O(x**4)
2038
+ # testing nseries for acsc at branch points
2039
+ assert acsc(1 + x)._eval_nseries(x, 3, None) == pi/2 - sqrt(2)*sqrt(x) + \
2040
+ 5*sqrt(2)*x**(S(3)/2)/12 - 43*sqrt(2)*x**(S(5)/2)/160 + O(x**3)
2041
+ assert acsc(-1 + x)._eval_nseries(x, 3, None) == -pi/2 + sqrt(2)*sqrt(-x) - \
2042
+ 5*sqrt(2)*(-x)**(S(3)/2)/12 + 43*sqrt(2)*(-x)**(S(5)/2)/160 + O(x**3)
2043
+ assert acsc(exp(x))._eval_nseries(x, 3, None) == pi/2 - sqrt(2)*sqrt(x) + \
2044
+ sqrt(2)*x**(S(3)/2)/6 - sqrt(2)*x**(S(5)/2)/120 + O(x**3)
2045
+ assert acsc(-exp(x))._eval_nseries(x, 3, None) == -pi/2 + sqrt(2)*sqrt(x) - \
2046
+ sqrt(2)*x**(S(3)/2)/6 + sqrt(2)*x**(S(5)/2)/120 + O(x**3)
2047
+
2048
+
2049
+ def test_issue_8653():
2050
+ n = Symbol('n', integer=True)
2051
+ assert sin(n).is_irrational is None
2052
+ assert cos(n).is_irrational is None
2053
+ assert tan(n).is_irrational is None
2054
+
2055
+
2056
+ def test_issue_9157():
2057
+ n = Symbol('n', integer=True, positive=True)
2058
+ assert atan(n - 1).is_nonnegative is True
2059
+
2060
+
2061
+ def test_trig_period():
2062
+ x, y = symbols('x, y')
2063
+
2064
+ assert sin(x).period() == 2*pi
2065
+ assert cos(x).period() == 2*pi
2066
+ assert tan(x).period() == pi
2067
+ assert cot(x).period() == pi
2068
+ assert sec(x).period() == 2*pi
2069
+ assert csc(x).period() == 2*pi
2070
+ assert sin(2*x).period() == pi
2071
+ assert cot(4*x - 6).period() == pi/4
2072
+ assert cos((-3)*x).period() == pi*Rational(2, 3)
2073
+ assert cos(x*y).period(x) == 2*pi/abs(y)
2074
+ assert sin(3*x*y + 2*pi).period(y) == 2*pi/abs(3*x)
2075
+ assert tan(3*x).period(y) is S.Zero
2076
+ raises(NotImplementedError, lambda: sin(x**2).period(x))
2077
+
2078
+
2079
+ def test_issue_7171():
2080
+ assert sin(x).rewrite(sqrt) == sin(x)
2081
+ assert sin(x).rewrite(pow) == sin(x)
2082
+
2083
+
2084
+ def test_issue_11864():
2085
+ w, k = symbols('w, k', real=True)
2086
+ F = Piecewise((1, Eq(2*pi*k, 0)), (sin(pi*k)/(pi*k), True))
2087
+ soln = Piecewise((1, Eq(2*pi*k, 0)), (sinc(pi*k), True))
2088
+ assert F.rewrite(sinc) == soln
2089
+
2090
+ def test_real_assumptions():
2091
+ z = Symbol('z', real=False, finite=True)
2092
+ assert sin(z).is_real is None
2093
+ assert cos(z).is_real is None
2094
+ assert tan(z).is_real is False
2095
+ assert sec(z).is_real is None
2096
+ assert csc(z).is_real is None
2097
+ assert cot(z).is_real is False
2098
+ assert asin(p).is_real is None
2099
+ assert asin(n).is_real is None
2100
+ assert asec(p).is_real is None
2101
+ assert asec(n).is_real is None
2102
+ assert acos(p).is_real is None
2103
+ assert acos(n).is_real is None
2104
+ assert acsc(p).is_real is None
2105
+ assert acsc(n).is_real is None
2106
+ assert atan(p).is_positive is True
2107
+ assert atan(n).is_negative is True
2108
+ assert acot(p).is_positive is True
2109
+ assert acot(n).is_negative is True
2110
+
2111
+ def test_issue_14320():
2112
+ assert asin(sin(2)) == -2 + pi and (-pi/2 <= -2 + pi <= pi/2) and sin(2) == sin(-2 + pi)
2113
+ assert asin(cos(2)) == -2 + pi/2 and (-pi/2 <= -2 + pi/2 <= pi/2) and cos(2) == sin(-2 + pi/2)
2114
+ assert acos(sin(2)) == -pi/2 + 2 and (0 <= -pi/2 + 2 <= pi) and sin(2) == cos(-pi/2 + 2)
2115
+ assert acos(cos(20)) == -6*pi + 20 and (0 <= -6*pi + 20 <= pi) and cos(20) == cos(-6*pi + 20)
2116
+ assert acos(cos(30)) == -30 + 10*pi and (0 <= -30 + 10*pi <= pi) and cos(30) == cos(-30 + 10*pi)
2117
+
2118
+ assert atan(tan(17)) == -5*pi + 17 and (-pi/2 < -5*pi + 17 < pi/2) and tan(17) == tan(-5*pi + 17)
2119
+ assert atan(tan(15)) == -5*pi + 15 and (-pi/2 < -5*pi + 15 < pi/2) and tan(15) == tan(-5*pi + 15)
2120
+ assert atan(cot(12)) == -12 + pi*Rational(7, 2) and (-pi/2 < -12 + pi*Rational(7, 2) < pi/2) and cot(12) == tan(-12 + pi*Rational(7, 2))
2121
+ assert acot(cot(15)) == -5*pi + 15 and (-pi/2 < -5*pi + 15 <= pi/2) and cot(15) == cot(-5*pi + 15)
2122
+ assert acot(tan(19)) == -19 + pi*Rational(13, 2) and (-pi/2 < -19 + pi*Rational(13, 2) <= pi/2) and tan(19) == cot(-19 + pi*Rational(13, 2))
2123
+
2124
+ assert asec(sec(11)) == -11 + 4*pi and (0 <= -11 + 4*pi <= pi) and cos(11) == cos(-11 + 4*pi)
2125
+ assert asec(csc(13)) == -13 + pi*Rational(9, 2) and (0 <= -13 + pi*Rational(9, 2) <= pi) and sin(13) == cos(-13 + pi*Rational(9, 2))
2126
+ assert acsc(csc(14)) == -4*pi + 14 and (-pi/2 <= -4*pi + 14 <= pi/2) and sin(14) == sin(-4*pi + 14)
2127
+ assert acsc(sec(10)) == pi*Rational(-7, 2) + 10 and (-pi/2 <= pi*Rational(-7, 2) + 10 <= pi/2) and cos(10) == sin(pi*Rational(-7, 2) + 10)
2128
+
2129
+ def test_issue_14543():
2130
+ assert sec(2*pi + 11) == sec(11)
2131
+ assert sec(2*pi - 11) == sec(11)
2132
+ assert sec(pi + 11) == -sec(11)
2133
+ assert sec(pi - 11) == -sec(11)
2134
+
2135
+ assert csc(2*pi + 17) == csc(17)
2136
+ assert csc(2*pi - 17) == -csc(17)
2137
+ assert csc(pi + 17) == -csc(17)
2138
+ assert csc(pi - 17) == csc(17)
2139
+
2140
+ x = Symbol('x')
2141
+ assert csc(pi/2 + x) == sec(x)
2142
+ assert csc(pi/2 - x) == sec(x)
2143
+ assert csc(pi*Rational(3, 2) + x) == -sec(x)
2144
+ assert csc(pi*Rational(3, 2) - x) == -sec(x)
2145
+
2146
+ assert sec(pi/2 - x) == csc(x)
2147
+ assert sec(pi/2 + x) == -csc(x)
2148
+ assert sec(pi*Rational(3, 2) + x) == csc(x)
2149
+ assert sec(pi*Rational(3, 2) - x) == -csc(x)
2150
+
2151
+
2152
+ def test_as_real_imag():
2153
+ # This is for https://github.com/sympy/sympy/issues/17142
2154
+ # If it start failing again in irrelevant builds or in the master
2155
+ # please open up the issue again.
2156
+ expr = atan(I/(I + I*tan(1)))
2157
+ assert expr.as_real_imag() == (expr, 0)
2158
+
2159
+
2160
+ def test_issue_18746():
2161
+ e3 = cos(S.Pi*(x/4 + 1/4))
2162
+ assert e3.period() == 8
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