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env-llmeval/lib/python3.10/site-packages/sympy/functions/special/benchmarks/bench_special.py ADDED
@@ -0,0 +1,8 @@
 
 
 
 
 
 
 
 
 
1
+ from sympy.core.symbol import symbols
2
+ from sympy.functions.special.spherical_harmonics import Ynm
3
+
4
+ x, y = symbols('x,y')
5
+
6
+
7
+ def timeit_Ynm_xy():
8
+ Ynm(1, 1, x, y)
env-llmeval/lib/python3.10/site-packages/sympy/functions/special/bessel.py ADDED
@@ -0,0 +1,2089 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ from functools import wraps
2
+
3
+ from sympy.core import S
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, _mexpand
8
+ from sympy.core.logic import fuzzy_or, fuzzy_not
9
+ from sympy.core.numbers import Rational, pi, I
10
+ from sympy.core.power import Pow
11
+ from sympy.core.symbol import Dummy, Wild
12
+ from sympy.core.sympify import sympify
13
+ from sympy.functions.combinatorial.factorials import factorial
14
+ from sympy.functions.elementary.trigonometric import sin, cos, csc, cot
15
+ from sympy.functions.elementary.integers import ceiling
16
+ from sympy.functions.elementary.exponential import exp, log
17
+ from sympy.functions.elementary.miscellaneous import cbrt, sqrt, root
18
+ from sympy.functions.elementary.complexes import (Abs, re, im, polar_lift, unpolarify)
19
+ from sympy.functions.special.gamma_functions import gamma, digamma, uppergamma
20
+ from sympy.functions.special.hyper import hyper
21
+ from sympy.polys.orthopolys import spherical_bessel_fn
22
+
23
+ from mpmath import mp, workprec
24
+
25
+ # TODO
26
+ # o Scorer functions G1 and G2
27
+ # o Asymptotic expansions
28
+ # These are possible, e.g. for fixed order, but since the bessel type
29
+ # functions are oscillatory they are not actually tractable at
30
+ # infinity, so this is not particularly useful right now.
31
+ # o Nicer series expansions.
32
+ # o More rewriting.
33
+ # o Add solvers to ode.py (or rather add solvers for the hypergeometric equation).
34
+
35
+
36
+ class BesselBase(Function):
37
+ """
38
+ Abstract base class for Bessel-type functions.
39
+
40
+ This class is meant to reduce code duplication.
41
+ All Bessel-type functions can 1) be differentiated, with the derivatives
42
+ expressed in terms of similar functions, and 2) be rewritten in terms
43
+ of other Bessel-type functions.
44
+
45
+ Here, Bessel-type functions are assumed to have one complex parameter.
46
+
47
+ To use this base class, define class attributes ``_a`` and ``_b`` such that
48
+ ``2*F_n' = -_a*F_{n+1} + b*F_{n-1}``.
49
+
50
+ """
51
+
52
+ @property
53
+ def order(self):
54
+ """ The order of the Bessel-type function. """
55
+ return self.args[0]
56
+
57
+ @property
58
+ def argument(self):
59
+ """ The argument of the Bessel-type function. """
60
+ return self.args[1]
61
+
62
+ @classmethod
63
+ def eval(cls, nu, z):
64
+ return
65
+
66
+ def fdiff(self, argindex=2):
67
+ if argindex != 2:
68
+ raise ArgumentIndexError(self, argindex)
69
+ return (self._b/2 * self.__class__(self.order - 1, self.argument) -
70
+ self._a/2 * self.__class__(self.order + 1, self.argument))
71
+
72
+ def _eval_conjugate(self):
73
+ z = self.argument
74
+ if z.is_extended_negative is False:
75
+ return self.__class__(self.order.conjugate(), z.conjugate())
76
+
77
+ def _eval_is_meromorphic(self, x, a):
78
+ nu, z = self.order, self.argument
79
+
80
+ if nu.has(x):
81
+ return False
82
+ if not z._eval_is_meromorphic(x, a):
83
+ return None
84
+ z0 = z.subs(x, a)
85
+ if nu.is_integer:
86
+ if isinstance(self, (besselj, besseli, hn1, hn2, jn, yn)) or not nu.is_zero:
87
+ return fuzzy_not(z0.is_infinite)
88
+ return fuzzy_not(fuzzy_or([z0.is_zero, z0.is_infinite]))
89
+
90
+ def _eval_expand_func(self, **hints):
91
+ nu, z, f = self.order, self.argument, self.__class__
92
+ if nu.is_real:
93
+ if (nu - 1).is_positive:
94
+ return (-self._a*self._b*f(nu - 2, z)._eval_expand_func() +
95
+ 2*self._a*(nu - 1)*f(nu - 1, z)._eval_expand_func()/z)
96
+ elif (nu + 1).is_negative:
97
+ return (2*self._b*(nu + 1)*f(nu + 1, z)._eval_expand_func()/z -
98
+ self._a*self._b*f(nu + 2, z)._eval_expand_func())
99
+ return self
100
+
101
+ def _eval_simplify(self, **kwargs):
102
+ from sympy.simplify.simplify import besselsimp
103
+ return besselsimp(self)
104
+
105
+
106
+ class besselj(BesselBase):
107
+ r"""
108
+ Bessel function of the first kind.
109
+
110
+ Explanation
111
+ ===========
112
+
113
+ The Bessel $J$ function of order $\nu$ is defined to be the function
114
+ satisfying Bessel's differential equation
115
+
116
+ .. math ::
117
+ z^2 \frac{\mathrm{d}^2 w}{\mathrm{d}z^2}
118
+ + z \frac{\mathrm{d}w}{\mathrm{d}z} + (z^2 - \nu^2) w = 0,
119
+
120
+ with Laurent expansion
121
+
122
+ .. math ::
123
+ J_\nu(z) = z^\nu \left(\frac{1}{\Gamma(\nu + 1) 2^\nu} + O(z^2) \right),
124
+
125
+ if $\nu$ is not a negative integer. If $\nu=-n \in \mathbb{Z}_{<0}$
126
+ *is* a negative integer, then the definition is
127
+
128
+ .. math ::
129
+ J_{-n}(z) = (-1)^n J_n(z).
130
+
131
+ Examples
132
+ ========
133
+
134
+ Create a Bessel function object:
135
+
136
+ >>> from sympy import besselj, jn
137
+ >>> from sympy.abc import z, n
138
+ >>> b = besselj(n, z)
139
+
140
+ Differentiate it:
141
+
142
+ >>> b.diff(z)
143
+ besselj(n - 1, z)/2 - besselj(n + 1, z)/2
144
+
145
+ Rewrite in terms of spherical Bessel functions:
146
+
147
+ >>> b.rewrite(jn)
148
+ sqrt(2)*sqrt(z)*jn(n - 1/2, z)/sqrt(pi)
149
+
150
+ Access the parameter and argument:
151
+
152
+ >>> b.order
153
+ n
154
+ >>> b.argument
155
+ z
156
+
157
+ See Also
158
+ ========
159
+
160
+ bessely, besseli, besselk
161
+
162
+ References
163
+ ==========
164
+
165
+ .. [1] Abramowitz, Milton; Stegun, Irene A., eds. (1965), "Chapter 9",
166
+ Handbook of Mathematical Functions with Formulas, Graphs, and
167
+ Mathematical Tables
168
+ .. [2] Luke, Y. L. (1969), The Special Functions and Their
169
+ Approximations, Volume 1
170
+ .. [3] https://en.wikipedia.org/wiki/Bessel_function
171
+ .. [4] https://functions.wolfram.com/Bessel-TypeFunctions/BesselJ/
172
+
173
+ """
174
+
175
+ _a = S.One
176
+ _b = S.One
177
+
178
+ @classmethod
179
+ def eval(cls, nu, z):
180
+ if z.is_zero:
181
+ if nu.is_zero:
182
+ return S.One
183
+ elif (nu.is_integer and nu.is_zero is False) or re(nu).is_positive:
184
+ return S.Zero
185
+ elif re(nu).is_negative and not (nu.is_integer is True):
186
+ return S.ComplexInfinity
187
+ elif nu.is_imaginary:
188
+ return S.NaN
189
+ if z in (S.Infinity, S.NegativeInfinity):
190
+ return S.Zero
191
+
192
+ if z.could_extract_minus_sign():
193
+ return (z)**nu*(-z)**(-nu)*besselj(nu, -z)
194
+ if nu.is_integer:
195
+ if nu.could_extract_minus_sign():
196
+ return S.NegativeOne**(-nu)*besselj(-nu, z)
197
+ newz = z.extract_multiplicatively(I)
198
+ if newz: # NOTE we don't want to change the function if z==0
199
+ return I**(nu)*besseli(nu, newz)
200
+
201
+ # branch handling:
202
+ if nu.is_integer:
203
+ newz = unpolarify(z)
204
+ if newz != z:
205
+ return besselj(nu, newz)
206
+ else:
207
+ newz, n = z.extract_branch_factor()
208
+ if n != 0:
209
+ return exp(2*n*pi*nu*I)*besselj(nu, newz)
210
+ nnu = unpolarify(nu)
211
+ if nu != nnu:
212
+ return besselj(nnu, z)
213
+
214
+ def _eval_rewrite_as_besseli(self, nu, z, **kwargs):
215
+ return exp(I*pi*nu/2)*besseli(nu, polar_lift(-I)*z)
216
+
217
+ def _eval_rewrite_as_bessely(self, nu, z, **kwargs):
218
+ if nu.is_integer is False:
219
+ return csc(pi*nu)*bessely(-nu, z) - cot(pi*nu)*bessely(nu, z)
220
+
221
+ def _eval_rewrite_as_jn(self, nu, z, **kwargs):
222
+ return sqrt(2*z/pi)*jn(nu - S.Half, self.argument)
223
+
224
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
225
+ nu, z = self.args
226
+ try:
227
+ arg = z.as_leading_term(x)
228
+ except NotImplementedError:
229
+ return self
230
+ c, e = arg.as_coeff_exponent(x)
231
+
232
+ if e.is_positive:
233
+ return arg**nu/(2**nu*gamma(nu + 1))
234
+ elif e.is_negative:
235
+ cdir = 1 if cdir == 0 else cdir
236
+ sign = c*cdir**e
237
+ if not sign.is_negative:
238
+ # Refer Abramowitz and Stegun 1965, p. 364 for more information on
239
+ # asymptotic approximation of besselj function.
240
+ return sqrt(2)*cos(z - pi*(2*nu + 1)/4)/sqrt(pi*z)
241
+ return self
242
+
243
+ return super(besselj, self)._eval_as_leading_term(x, logx, cdir)
244
+
245
+ def _eval_is_extended_real(self):
246
+ nu, z = self.args
247
+ if nu.is_integer and z.is_extended_real:
248
+ return True
249
+
250
+ def _eval_nseries(self, x, n, logx, cdir=0):
251
+ # Refer https://functions.wolfram.com/Bessel-TypeFunctions/BesselJ/06/01/04/01/01/0003/
252
+ # for more information on nseries expansion of besselj function.
253
+ from sympy.series.order import Order
254
+ nu, z = self.args
255
+
256
+ # In case of powers less than 1, number of terms need to be computed
257
+ # separately to avoid repeated callings of _eval_nseries with wrong n
258
+ try:
259
+ _, exp = z.leadterm(x)
260
+ except (ValueError, NotImplementedError):
261
+ return self
262
+
263
+ if exp.is_positive:
264
+ newn = ceiling(n/exp)
265
+ o = Order(x**n, x)
266
+ r = (z/2)._eval_nseries(x, n, logx, cdir).removeO()
267
+ if r is S.Zero:
268
+ return o
269
+ t = (_mexpand(r**2) + o).removeO()
270
+
271
+ term = r**nu/gamma(nu + 1)
272
+ s = [term]
273
+ for k in range(1, (newn + 1)//2):
274
+ term *= -t/(k*(nu + k))
275
+ term = (_mexpand(term) + o).removeO()
276
+ s.append(term)
277
+ return Add(*s) + o
278
+
279
+ return super(besselj, self)._eval_nseries(x, n, logx, cdir)
280
+
281
+
282
+ class bessely(BesselBase):
283
+ r"""
284
+ Bessel function of the second kind.
285
+
286
+ Explanation
287
+ ===========
288
+
289
+ The Bessel $Y$ function of order $\nu$ is defined as
290
+
291
+ .. math ::
292
+ Y_\nu(z) = \lim_{\mu \to \nu} \frac{J_\mu(z) \cos(\pi \mu)
293
+ - J_{-\mu}(z)}{\sin(\pi \mu)},
294
+
295
+ where $J_\mu(z)$ is the Bessel function of the first kind.
296
+
297
+ It is a solution to Bessel's equation, and linearly independent from
298
+ $J_\nu$.
299
+
300
+ Examples
301
+ ========
302
+
303
+ >>> from sympy import bessely, yn
304
+ >>> from sympy.abc import z, n
305
+ >>> b = bessely(n, z)
306
+ >>> b.diff(z)
307
+ bessely(n - 1, z)/2 - bessely(n + 1, z)/2
308
+ >>> b.rewrite(yn)
309
+ sqrt(2)*sqrt(z)*yn(n - 1/2, z)/sqrt(pi)
310
+
311
+ See Also
312
+ ========
313
+
314
+ besselj, besseli, besselk
315
+
316
+ References
317
+ ==========
318
+
319
+ .. [1] https://functions.wolfram.com/Bessel-TypeFunctions/BesselY/
320
+
321
+ """
322
+
323
+ _a = S.One
324
+ _b = S.One
325
+
326
+ @classmethod
327
+ def eval(cls, nu, z):
328
+ if z.is_zero:
329
+ if nu.is_zero:
330
+ return S.NegativeInfinity
331
+ elif re(nu).is_zero is False:
332
+ return S.ComplexInfinity
333
+ elif re(nu).is_zero:
334
+ return S.NaN
335
+ if z in (S.Infinity, S.NegativeInfinity):
336
+ return S.Zero
337
+ if z == I*S.Infinity:
338
+ return exp(I*pi*(nu + 1)/2) * S.Infinity
339
+ if z == I*S.NegativeInfinity:
340
+ return exp(-I*pi*(nu + 1)/2) * S.Infinity
341
+
342
+ if nu.is_integer:
343
+ if nu.could_extract_minus_sign():
344
+ return S.NegativeOne**(-nu)*bessely(-nu, z)
345
+
346
+ def _eval_rewrite_as_besselj(self, nu, z, **kwargs):
347
+ if nu.is_integer is False:
348
+ return csc(pi*nu)*(cos(pi*nu)*besselj(nu, z) - besselj(-nu, z))
349
+
350
+ def _eval_rewrite_as_besseli(self, nu, z, **kwargs):
351
+ aj = self._eval_rewrite_as_besselj(*self.args)
352
+ if aj:
353
+ return aj.rewrite(besseli)
354
+
355
+ def _eval_rewrite_as_yn(self, nu, z, **kwargs):
356
+ return sqrt(2*z/pi) * yn(nu - S.Half, self.argument)
357
+
358
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
359
+ nu, z = self.args
360
+ try:
361
+ arg = z.as_leading_term(x)
362
+ except NotImplementedError:
363
+ return self
364
+ c, e = arg.as_coeff_exponent(x)
365
+
366
+ if e.is_positive:
367
+ term_one = ((2/pi)*log(z/2)*besselj(nu, z))
368
+ term_two = -(z/2)**(-nu)*factorial(nu - 1)/pi if (nu).is_positive else S.Zero
369
+ term_three = -(z/2)**nu/(pi*factorial(nu))*(digamma(nu + 1) - S.EulerGamma)
370
+ arg = Add(*[term_one, term_two, term_three]).as_leading_term(x, logx=logx)
371
+ return arg
372
+ elif e.is_negative:
373
+ cdir = 1 if cdir == 0 else cdir
374
+ sign = c*cdir**e
375
+ if not sign.is_negative:
376
+ # Refer Abramowitz and Stegun 1965, p. 364 for more information on
377
+ # asymptotic approximation of bessely function.
378
+ return sqrt(2)*(-sin(pi*nu/2 - z + pi/4) + 3*cos(pi*nu/2 - z + pi/4)/(8*z))*sqrt(1/z)/sqrt(pi)
379
+ return self
380
+
381
+ return super(bessely, self)._eval_as_leading_term(x, logx, cdir)
382
+
383
+ def _eval_is_extended_real(self):
384
+ nu, z = self.args
385
+ if nu.is_integer and z.is_positive:
386
+ return True
387
+
388
+ def _eval_nseries(self, x, n, logx, cdir=0):
389
+ # Refer https://functions.wolfram.com/Bessel-TypeFunctions/BesselY/06/01/04/01/02/0008/
390
+ # for more information on nseries expansion of bessely function.
391
+ from sympy.series.order import Order
392
+ nu, z = self.args
393
+
394
+ # In case of powers less than 1, number of terms need to be computed
395
+ # separately to avoid repeated callings of _eval_nseries with wrong n
396
+ try:
397
+ _, exp = z.leadterm(x)
398
+ except (ValueError, NotImplementedError):
399
+ return self
400
+
401
+ if exp.is_positive and nu.is_integer:
402
+ newn = ceiling(n/exp)
403
+ bn = besselj(nu, z)
404
+ a = ((2/pi)*log(z/2)*bn)._eval_nseries(x, n, logx, cdir)
405
+
406
+ b, c = [], []
407
+ o = Order(x**n, x)
408
+ r = (z/2)._eval_nseries(x, n, logx, cdir).removeO()
409
+ if r is S.Zero:
410
+ return o
411
+ t = (_mexpand(r**2) + o).removeO()
412
+
413
+ if nu > S.Zero:
414
+ term = r**(-nu)*factorial(nu - 1)/pi
415
+ b.append(term)
416
+ for k in range(1, nu):
417
+ denom = (nu - k)*k
418
+ if denom == S.Zero:
419
+ term *= t/k
420
+ else:
421
+ term *= t/denom
422
+ term = (_mexpand(term) + o).removeO()
423
+ b.append(term)
424
+
425
+ p = r**nu/(pi*factorial(nu))
426
+ term = p*(digamma(nu + 1) - S.EulerGamma)
427
+ c.append(term)
428
+ for k in range(1, (newn + 1)//2):
429
+ p *= -t/(k*(k + nu))
430
+ p = (_mexpand(p) + o).removeO()
431
+ term = p*(digamma(k + nu + 1) + digamma(k + 1))
432
+ c.append(term)
433
+ return a - Add(*b) - Add(*c) # Order term comes from a
434
+
435
+ return super(bessely, self)._eval_nseries(x, n, logx, cdir)
436
+
437
+
438
+ class besseli(BesselBase):
439
+ r"""
440
+ Modified Bessel function of the first kind.
441
+
442
+ Explanation
443
+ ===========
444
+
445
+ The Bessel $I$ function is a solution to the modified Bessel equation
446
+
447
+ .. math ::
448
+ z^2 \frac{\mathrm{d}^2 w}{\mathrm{d}z^2}
449
+ + z \frac{\mathrm{d}w}{\mathrm{d}z} + (z^2 + \nu^2)^2 w = 0.
450
+
451
+ It can be defined as
452
+
453
+ .. math ::
454
+ I_\nu(z) = i^{-\nu} J_\nu(iz),
455
+
456
+ where $J_\nu(z)$ is the Bessel function of the first kind.
457
+
458
+ Examples
459
+ ========
460
+
461
+ >>> from sympy import besseli
462
+ >>> from sympy.abc import z, n
463
+ >>> besseli(n, z).diff(z)
464
+ besseli(n - 1, z)/2 + besseli(n + 1, z)/2
465
+
466
+ See Also
467
+ ========
468
+
469
+ besselj, bessely, besselk
470
+
471
+ References
472
+ ==========
473
+
474
+ .. [1] https://functions.wolfram.com/Bessel-TypeFunctions/BesselI/
475
+
476
+ """
477
+
478
+ _a = -S.One
479
+ _b = S.One
480
+
481
+ @classmethod
482
+ def eval(cls, nu, z):
483
+ if z.is_zero:
484
+ if nu.is_zero:
485
+ return S.One
486
+ elif (nu.is_integer and nu.is_zero is False) or re(nu).is_positive:
487
+ return S.Zero
488
+ elif re(nu).is_negative and not (nu.is_integer is True):
489
+ return S.ComplexInfinity
490
+ elif nu.is_imaginary:
491
+ return S.NaN
492
+ if im(z) in (S.Infinity, S.NegativeInfinity):
493
+ return S.Zero
494
+ if z is S.Infinity:
495
+ return S.Infinity
496
+ if z is S.NegativeInfinity:
497
+ return (-1)**nu*S.Infinity
498
+
499
+ if z.could_extract_minus_sign():
500
+ return (z)**nu*(-z)**(-nu)*besseli(nu, -z)
501
+ if nu.is_integer:
502
+ if nu.could_extract_minus_sign():
503
+ return besseli(-nu, z)
504
+ newz = z.extract_multiplicatively(I)
505
+ if newz: # NOTE we don't want to change the function if z==0
506
+ return I**(-nu)*besselj(nu, -newz)
507
+
508
+ # branch handling:
509
+ if nu.is_integer:
510
+ newz = unpolarify(z)
511
+ if newz != z:
512
+ return besseli(nu, newz)
513
+ else:
514
+ newz, n = z.extract_branch_factor()
515
+ if n != 0:
516
+ return exp(2*n*pi*nu*I)*besseli(nu, newz)
517
+ nnu = unpolarify(nu)
518
+ if nu != nnu:
519
+ return besseli(nnu, z)
520
+
521
+ def _eval_rewrite_as_besselj(self, nu, z, **kwargs):
522
+ return exp(-I*pi*nu/2)*besselj(nu, polar_lift(I)*z)
523
+
524
+ def _eval_rewrite_as_bessely(self, nu, z, **kwargs):
525
+ aj = self._eval_rewrite_as_besselj(*self.args)
526
+ if aj:
527
+ return aj.rewrite(bessely)
528
+
529
+ def _eval_rewrite_as_jn(self, nu, z, **kwargs):
530
+ return self._eval_rewrite_as_besselj(*self.args).rewrite(jn)
531
+
532
+ def _eval_is_extended_real(self):
533
+ nu, z = self.args
534
+ if nu.is_integer and z.is_extended_real:
535
+ return True
536
+
537
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
538
+ nu, z = self.args
539
+ try:
540
+ arg = z.as_leading_term(x)
541
+ except NotImplementedError:
542
+ return self
543
+ c, e = arg.as_coeff_exponent(x)
544
+
545
+ if e.is_positive:
546
+ return arg**nu/(2**nu*gamma(nu + 1))
547
+ elif e.is_negative:
548
+ cdir = 1 if cdir == 0 else cdir
549
+ sign = c*cdir**e
550
+ if not sign.is_negative:
551
+ # Refer Abramowitz and Stegun 1965, p. 377 for more information on
552
+ # asymptotic approximation of besseli function.
553
+ return exp(z)/sqrt(2*pi*z)
554
+ return self
555
+
556
+ return super(besseli, self)._eval_as_leading_term(x, logx, cdir)
557
+
558
+ def _eval_nseries(self, x, n, logx, cdir=0):
559
+ # Refer https://functions.wolfram.com/Bessel-TypeFunctions/BesselI/06/01/04/01/01/0003/
560
+ # for more information on nseries expansion of besseli function.
561
+ from sympy.series.order import Order
562
+ nu, z = self.args
563
+
564
+ # In case of powers less than 1, number of terms need to be computed
565
+ # separately to avoid repeated callings of _eval_nseries with wrong n
566
+ try:
567
+ _, exp = z.leadterm(x)
568
+ except (ValueError, NotImplementedError):
569
+ return self
570
+
571
+ if exp.is_positive:
572
+ newn = ceiling(n/exp)
573
+ o = Order(x**n, x)
574
+ r = (z/2)._eval_nseries(x, n, logx, cdir).removeO()
575
+ if r is S.Zero:
576
+ return o
577
+ t = (_mexpand(r**2) + o).removeO()
578
+
579
+ term = r**nu/gamma(nu + 1)
580
+ s = [term]
581
+ for k in range(1, (newn + 1)//2):
582
+ term *= t/(k*(nu + k))
583
+ term = (_mexpand(term) + o).removeO()
584
+ s.append(term)
585
+ return Add(*s) + o
586
+
587
+ return super(besseli, self)._eval_nseries(x, n, logx, cdir)
588
+
589
+
590
+ class besselk(BesselBase):
591
+ r"""
592
+ Modified Bessel function of the second kind.
593
+
594
+ Explanation
595
+ ===========
596
+
597
+ The Bessel $K$ function of order $\nu$ is defined as
598
+
599
+ .. math ::
600
+ K_\nu(z) = \lim_{\mu \to \nu} \frac{\pi}{2}
601
+ \frac{I_{-\mu}(z) -I_\mu(z)}{\sin(\pi \mu)},
602
+
603
+ where $I_\mu(z)$ is the modified Bessel function of the first kind.
604
+
605
+ It is a solution of the modified Bessel equation, and linearly independent
606
+ from $Y_\nu$.
607
+
608
+ Examples
609
+ ========
610
+
611
+ >>> from sympy import besselk
612
+ >>> from sympy.abc import z, n
613
+ >>> besselk(n, z).diff(z)
614
+ -besselk(n - 1, z)/2 - besselk(n + 1, z)/2
615
+
616
+ See Also
617
+ ========
618
+
619
+ besselj, besseli, bessely
620
+
621
+ References
622
+ ==========
623
+
624
+ .. [1] https://functions.wolfram.com/Bessel-TypeFunctions/BesselK/
625
+
626
+ """
627
+
628
+ _a = S.One
629
+ _b = -S.One
630
+
631
+ @classmethod
632
+ def eval(cls, nu, z):
633
+ if z.is_zero:
634
+ if nu.is_zero:
635
+ return S.Infinity
636
+ elif re(nu).is_zero is False:
637
+ return S.ComplexInfinity
638
+ elif re(nu).is_zero:
639
+ return S.NaN
640
+ if z in (S.Infinity, I*S.Infinity, I*S.NegativeInfinity):
641
+ return S.Zero
642
+
643
+ if nu.is_integer:
644
+ if nu.could_extract_minus_sign():
645
+ return besselk(-nu, z)
646
+
647
+ def _eval_rewrite_as_besseli(self, nu, z, **kwargs):
648
+ if nu.is_integer is False:
649
+ return pi*csc(pi*nu)*(besseli(-nu, z) - besseli(nu, z))/2
650
+
651
+ def _eval_rewrite_as_besselj(self, nu, z, **kwargs):
652
+ ai = self._eval_rewrite_as_besseli(*self.args)
653
+ if ai:
654
+ return ai.rewrite(besselj)
655
+
656
+ def _eval_rewrite_as_bessely(self, nu, z, **kwargs):
657
+ aj = self._eval_rewrite_as_besselj(*self.args)
658
+ if aj:
659
+ return aj.rewrite(bessely)
660
+
661
+ def _eval_rewrite_as_yn(self, nu, z, **kwargs):
662
+ ay = self._eval_rewrite_as_bessely(*self.args)
663
+ if ay:
664
+ return ay.rewrite(yn)
665
+
666
+ def _eval_is_extended_real(self):
667
+ nu, z = self.args
668
+ if nu.is_integer and z.is_positive:
669
+ return True
670
+
671
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
672
+ nu, z = self.args
673
+ try:
674
+ arg = z.as_leading_term(x)
675
+ except NotImplementedError:
676
+ return self
677
+ _, e = arg.as_coeff_exponent(x)
678
+
679
+ if e.is_positive:
680
+ term_one = ((-1)**(nu -1)*log(z/2)*besseli(nu, z))
681
+ term_two = (z/2)**(-nu)*factorial(nu - 1)/2 if (nu).is_positive else S.Zero
682
+ term_three = (-1)**nu*(z/2)**nu/(2*factorial(nu))*(digamma(nu + 1) - S.EulerGamma)
683
+ arg = Add(*[term_one, term_two, term_three]).as_leading_term(x, logx=logx)
684
+ return arg
685
+ elif e.is_negative:
686
+ # Refer Abramowitz and Stegun 1965, p. 378 for more information on
687
+ # asymptotic approximation of besselk function.
688
+ return sqrt(pi)*exp(-z)/sqrt(2*z)
689
+
690
+ return super(besselk, self)._eval_as_leading_term(x, logx, cdir)
691
+
692
+ def _eval_nseries(self, x, n, logx, cdir=0):
693
+ # Refer https://functions.wolfram.com/Bessel-TypeFunctions/BesselK/06/01/04/01/02/0008/
694
+ # for more information on nseries expansion of besselk function.
695
+ from sympy.series.order import Order
696
+ nu, z = self.args
697
+
698
+ # In case of powers less than 1, number of terms need to be computed
699
+ # separately to avoid repeated callings of _eval_nseries with wrong n
700
+ try:
701
+ _, exp = z.leadterm(x)
702
+ except (ValueError, NotImplementedError):
703
+ return self
704
+
705
+ if exp.is_positive and nu.is_integer:
706
+ newn = ceiling(n/exp)
707
+ bn = besseli(nu, z)
708
+ a = ((-1)**(nu - 1)*log(z/2)*bn)._eval_nseries(x, n, logx, cdir)
709
+
710
+ b, c = [], []
711
+ o = Order(x**n, x)
712
+ r = (z/2)._eval_nseries(x, n, logx, cdir).removeO()
713
+ if r is S.Zero:
714
+ return o
715
+ t = (_mexpand(r**2) + o).removeO()
716
+
717
+ if nu > S.Zero:
718
+ term = r**(-nu)*factorial(nu - 1)/2
719
+ b.append(term)
720
+ for k in range(1, nu):
721
+ denom = (k - nu)*k
722
+ if denom == S.Zero:
723
+ term *= t/k
724
+ else:
725
+ term *= t/denom
726
+ term = (_mexpand(term) + o).removeO()
727
+ b.append(term)
728
+
729
+ p = r**nu*(-1)**nu/(2*factorial(nu))
730
+ term = p*(digamma(nu + 1) - S.EulerGamma)
731
+ c.append(term)
732
+ for k in range(1, (newn + 1)//2):
733
+ p *= t/(k*(k + nu))
734
+ p = (_mexpand(p) + o).removeO()
735
+ term = p*(digamma(k + nu + 1) + digamma(k + 1))
736
+ c.append(term)
737
+ return a + Add(*b) + Add(*c) # Order term comes from a
738
+
739
+ return super(besselk, self)._eval_nseries(x, n, logx, cdir)
740
+
741
+
742
+ class hankel1(BesselBase):
743
+ r"""
744
+ Hankel function of the first kind.
745
+
746
+ Explanation
747
+ ===========
748
+
749
+ This function is defined as
750
+
751
+ .. math ::
752
+ H_\nu^{(1)} = J_\nu(z) + iY_\nu(z),
753
+
754
+ where $J_\nu(z)$ is the Bessel function of the first kind, and
755
+ $Y_\nu(z)$ is the Bessel function of the second kind.
756
+
757
+ It is a solution to Bessel's equation.
758
+
759
+ Examples
760
+ ========
761
+
762
+ >>> from sympy import hankel1
763
+ >>> from sympy.abc import z, n
764
+ >>> hankel1(n, z).diff(z)
765
+ hankel1(n - 1, z)/2 - hankel1(n + 1, z)/2
766
+
767
+ See Also
768
+ ========
769
+
770
+ hankel2, besselj, bessely
771
+
772
+ References
773
+ ==========
774
+
775
+ .. [1] https://functions.wolfram.com/Bessel-TypeFunctions/HankelH1/
776
+
777
+ """
778
+
779
+ _a = S.One
780
+ _b = S.One
781
+
782
+ def _eval_conjugate(self):
783
+ z = self.argument
784
+ if z.is_extended_negative is False:
785
+ return hankel2(self.order.conjugate(), z.conjugate())
786
+
787
+
788
+ class hankel2(BesselBase):
789
+ r"""
790
+ Hankel function of the second kind.
791
+
792
+ Explanation
793
+ ===========
794
+
795
+ This function is defined as
796
+
797
+ .. math ::
798
+ H_\nu^{(2)} = J_\nu(z) - iY_\nu(z),
799
+
800
+ where $J_\nu(z)$ is the Bessel function of the first kind, and
801
+ $Y_\nu(z)$ is the Bessel function of the second kind.
802
+
803
+ It is a solution to Bessel's equation, and linearly independent from
804
+ $H_\nu^{(1)}$.
805
+
806
+ Examples
807
+ ========
808
+
809
+ >>> from sympy import hankel2
810
+ >>> from sympy.abc import z, n
811
+ >>> hankel2(n, z).diff(z)
812
+ hankel2(n - 1, z)/2 - hankel2(n + 1, z)/2
813
+
814
+ See Also
815
+ ========
816
+
817
+ hankel1, besselj, bessely
818
+
819
+ References
820
+ ==========
821
+
822
+ .. [1] https://functions.wolfram.com/Bessel-TypeFunctions/HankelH2/
823
+
824
+ """
825
+
826
+ _a = S.One
827
+ _b = S.One
828
+
829
+ def _eval_conjugate(self):
830
+ z = self.argument
831
+ if z.is_extended_negative is False:
832
+ return hankel1(self.order.conjugate(), z.conjugate())
833
+
834
+
835
+ def assume_integer_order(fn):
836
+ @wraps(fn)
837
+ def g(self, nu, z):
838
+ if nu.is_integer:
839
+ return fn(self, nu, z)
840
+ return g
841
+
842
+
843
+ class SphericalBesselBase(BesselBase):
844
+ """
845
+ Base class for spherical Bessel functions.
846
+
847
+ These are thin wrappers around ordinary Bessel functions,
848
+ since spherical Bessel functions differ from the ordinary
849
+ ones just by a slight change in order.
850
+
851
+ To use this class, define the ``_eval_evalf()`` and ``_expand()`` methods.
852
+
853
+ """
854
+
855
+ def _expand(self, **hints):
856
+ """ Expand self into a polynomial. Nu is guaranteed to be Integer. """
857
+ raise NotImplementedError('expansion')
858
+
859
+ def _eval_expand_func(self, **hints):
860
+ if self.order.is_Integer:
861
+ return self._expand(**hints)
862
+ return self
863
+
864
+ def fdiff(self, argindex=2):
865
+ if argindex != 2:
866
+ raise ArgumentIndexError(self, argindex)
867
+ return self.__class__(self.order - 1, self.argument) - \
868
+ self * (self.order + 1)/self.argument
869
+
870
+
871
+ def _jn(n, z):
872
+ return (spherical_bessel_fn(n, z)*sin(z) +
873
+ S.NegativeOne**(n + 1)*spherical_bessel_fn(-n - 1, z)*cos(z))
874
+
875
+
876
+ def _yn(n, z):
877
+ # (-1)**(n + 1) * _jn(-n - 1, z)
878
+ return (S.NegativeOne**(n + 1) * spherical_bessel_fn(-n - 1, z)*sin(z) -
879
+ spherical_bessel_fn(n, z)*cos(z))
880
+
881
+
882
+ class jn(SphericalBesselBase):
883
+ r"""
884
+ Spherical Bessel function of the first kind.
885
+
886
+ Explanation
887
+ ===========
888
+
889
+ This function is a solution to the spherical Bessel equation
890
+
891
+ .. math ::
892
+ z^2 \frac{\mathrm{d}^2 w}{\mathrm{d}z^2}
893
+ + 2z \frac{\mathrm{d}w}{\mathrm{d}z} + (z^2 - \nu(\nu + 1)) w = 0.
894
+
895
+ It can be defined as
896
+
897
+ .. math ::
898
+ j_\nu(z) = \sqrt{\frac{\pi}{2z}} J_{\nu + \frac{1}{2}}(z),
899
+
900
+ where $J_\nu(z)$ is the Bessel function of the first kind.
901
+
902
+ The spherical Bessel functions of integral order are
903
+ calculated using the formula:
904
+
905
+ .. math:: j_n(z) = f_n(z) \sin{z} + (-1)^{n+1} f_{-n-1}(z) \cos{z},
906
+
907
+ where the coefficients $f_n(z)$ are available as
908
+ :func:`sympy.polys.orthopolys.spherical_bessel_fn`.
909
+
910
+ Examples
911
+ ========
912
+
913
+ >>> from sympy import Symbol, jn, sin, cos, expand_func, besselj, bessely
914
+ >>> z = Symbol("z")
915
+ >>> nu = Symbol("nu", integer=True)
916
+ >>> print(expand_func(jn(0, z)))
917
+ sin(z)/z
918
+ >>> expand_func(jn(1, z)) == sin(z)/z**2 - cos(z)/z
919
+ True
920
+ >>> expand_func(jn(3, z))
921
+ (-6/z**2 + 15/z**4)*sin(z) + (1/z - 15/z**3)*cos(z)
922
+ >>> jn(nu, z).rewrite(besselj)
923
+ sqrt(2)*sqrt(pi)*sqrt(1/z)*besselj(nu + 1/2, z)/2
924
+ >>> jn(nu, z).rewrite(bessely)
925
+ (-1)**nu*sqrt(2)*sqrt(pi)*sqrt(1/z)*bessely(-nu - 1/2, z)/2
926
+ >>> jn(2, 5.2+0.3j).evalf(20)
927
+ 0.099419756723640344491 - 0.054525080242173562897*I
928
+
929
+ See Also
930
+ ========
931
+
932
+ besselj, bessely, besselk, yn
933
+
934
+ References
935
+ ==========
936
+
937
+ .. [1] https://dlmf.nist.gov/10.47
938
+
939
+ """
940
+ @classmethod
941
+ def eval(cls, nu, z):
942
+ if z.is_zero:
943
+ if nu.is_zero:
944
+ return S.One
945
+ elif nu.is_integer:
946
+ if nu.is_positive:
947
+ return S.Zero
948
+ else:
949
+ return S.ComplexInfinity
950
+ if z in (S.NegativeInfinity, S.Infinity):
951
+ return S.Zero
952
+
953
+ def _eval_rewrite_as_besselj(self, nu, z, **kwargs):
954
+ return sqrt(pi/(2*z)) * besselj(nu + S.Half, z)
955
+
956
+ def _eval_rewrite_as_bessely(self, nu, z, **kwargs):
957
+ return S.NegativeOne**nu * sqrt(pi/(2*z)) * bessely(-nu - S.Half, z)
958
+
959
+ def _eval_rewrite_as_yn(self, nu, z, **kwargs):
960
+ return S.NegativeOne**(nu) * yn(-nu - 1, z)
961
+
962
+ def _expand(self, **hints):
963
+ return _jn(self.order, self.argument)
964
+
965
+ def _eval_evalf(self, prec):
966
+ if self.order.is_Integer:
967
+ return self.rewrite(besselj)._eval_evalf(prec)
968
+
969
+
970
+ class yn(SphericalBesselBase):
971
+ r"""
972
+ Spherical Bessel function of the second kind.
973
+
974
+ Explanation
975
+ ===========
976
+
977
+ This function is another solution to the spherical Bessel equation, and
978
+ linearly independent from $j_n$. It can be defined as
979
+
980
+ .. math ::
981
+ y_\nu(z) = \sqrt{\frac{\pi}{2z}} Y_{\nu + \frac{1}{2}}(z),
982
+
983
+ where $Y_\nu(z)$ is the Bessel function of the second kind.
984
+
985
+ For integral orders $n$, $y_n$ is calculated using the formula:
986
+
987
+ .. math:: y_n(z) = (-1)^{n+1} j_{-n-1}(z)
988
+
989
+ Examples
990
+ ========
991
+
992
+ >>> from sympy import Symbol, yn, sin, cos, expand_func, besselj, bessely
993
+ >>> z = Symbol("z")
994
+ >>> nu = Symbol("nu", integer=True)
995
+ >>> print(expand_func(yn(0, z)))
996
+ -cos(z)/z
997
+ >>> expand_func(yn(1, z)) == -cos(z)/z**2-sin(z)/z
998
+ True
999
+ >>> yn(nu, z).rewrite(besselj)
1000
+ (-1)**(nu + 1)*sqrt(2)*sqrt(pi)*sqrt(1/z)*besselj(-nu - 1/2, z)/2
1001
+ >>> yn(nu, z).rewrite(bessely)
1002
+ sqrt(2)*sqrt(pi)*sqrt(1/z)*bessely(nu + 1/2, z)/2
1003
+ >>> yn(2, 5.2+0.3j).evalf(20)
1004
+ 0.18525034196069722536 + 0.014895573969924817587*I
1005
+
1006
+ See Also
1007
+ ========
1008
+
1009
+ besselj, bessely, besselk, jn
1010
+
1011
+ References
1012
+ ==========
1013
+
1014
+ .. [1] https://dlmf.nist.gov/10.47
1015
+
1016
+ """
1017
+ @assume_integer_order
1018
+ def _eval_rewrite_as_besselj(self, nu, z, **kwargs):
1019
+ return S.NegativeOne**(nu+1) * sqrt(pi/(2*z)) * besselj(-nu - S.Half, z)
1020
+
1021
+ @assume_integer_order
1022
+ def _eval_rewrite_as_bessely(self, nu, z, **kwargs):
1023
+ return sqrt(pi/(2*z)) * bessely(nu + S.Half, z)
1024
+
1025
+ def _eval_rewrite_as_jn(self, nu, z, **kwargs):
1026
+ return S.NegativeOne**(nu + 1) * jn(-nu - 1, z)
1027
+
1028
+ def _expand(self, **hints):
1029
+ return _yn(self.order, self.argument)
1030
+
1031
+ def _eval_evalf(self, prec):
1032
+ if self.order.is_Integer:
1033
+ return self.rewrite(bessely)._eval_evalf(prec)
1034
+
1035
+
1036
+ class SphericalHankelBase(SphericalBesselBase):
1037
+
1038
+ @assume_integer_order
1039
+ def _eval_rewrite_as_besselj(self, nu, z, **kwargs):
1040
+ # jn +- I*yn
1041
+ # jn as beeselj: sqrt(pi/(2*z)) * besselj(nu + S.Half, z)
1042
+ # yn as besselj: (-1)**(nu+1) * sqrt(pi/(2*z)) * besselj(-nu - S.Half, z)
1043
+ hks = self._hankel_kind_sign
1044
+ return sqrt(pi/(2*z))*(besselj(nu + S.Half, z) +
1045
+ hks*I*S.NegativeOne**(nu+1)*besselj(-nu - S.Half, z))
1046
+
1047
+ @assume_integer_order
1048
+ def _eval_rewrite_as_bessely(self, nu, z, **kwargs):
1049
+ # jn +- I*yn
1050
+ # jn as bessely: (-1)**nu * sqrt(pi/(2*z)) * bessely(-nu - S.Half, z)
1051
+ # yn as bessely: sqrt(pi/(2*z)) * bessely(nu + S.Half, z)
1052
+ hks = self._hankel_kind_sign
1053
+ return sqrt(pi/(2*z))*(S.NegativeOne**nu*bessely(-nu - S.Half, z) +
1054
+ hks*I*bessely(nu + S.Half, z))
1055
+
1056
+ def _eval_rewrite_as_yn(self, nu, z, **kwargs):
1057
+ hks = self._hankel_kind_sign
1058
+ return jn(nu, z).rewrite(yn) + hks*I*yn(nu, z)
1059
+
1060
+ def _eval_rewrite_as_jn(self, nu, z, **kwargs):
1061
+ hks = self._hankel_kind_sign
1062
+ return jn(nu, z) + hks*I*yn(nu, z).rewrite(jn)
1063
+
1064
+ def _eval_expand_func(self, **hints):
1065
+ if self.order.is_Integer:
1066
+ return self._expand(**hints)
1067
+ else:
1068
+ nu = self.order
1069
+ z = self.argument
1070
+ hks = self._hankel_kind_sign
1071
+ return jn(nu, z) + hks*I*yn(nu, z)
1072
+
1073
+ def _expand(self, **hints):
1074
+ n = self.order
1075
+ z = self.argument
1076
+ hks = self._hankel_kind_sign
1077
+
1078
+ # fully expanded version
1079
+ # return ((fn(n, z) * sin(z) +
1080
+ # (-1)**(n + 1) * fn(-n - 1, z) * cos(z)) + # jn
1081
+ # (hks * I * (-1)**(n + 1) *
1082
+ # (fn(-n - 1, z) * hk * I * sin(z) +
1083
+ # (-1)**(-n) * fn(n, z) * I * cos(z))) # +-I*yn
1084
+ # )
1085
+
1086
+ return (_jn(n, z) + hks*I*_yn(n, z)).expand()
1087
+
1088
+ def _eval_evalf(self, prec):
1089
+ if self.order.is_Integer:
1090
+ return self.rewrite(besselj)._eval_evalf(prec)
1091
+
1092
+
1093
+ class hn1(SphericalHankelBase):
1094
+ r"""
1095
+ Spherical Hankel function of the first kind.
1096
+
1097
+ Explanation
1098
+ ===========
1099
+
1100
+ This function is defined as
1101
+
1102
+ .. math:: h_\nu^(1)(z) = j_\nu(z) + i y_\nu(z),
1103
+
1104
+ where $j_\nu(z)$ and $y_\nu(z)$ are the spherical
1105
+ Bessel function of the first and second kinds.
1106
+
1107
+ For integral orders $n$, $h_n^(1)$ is calculated using the formula:
1108
+
1109
+ .. math:: h_n^(1)(z) = j_{n}(z) + i (-1)^{n+1} j_{-n-1}(z)
1110
+
1111
+ Examples
1112
+ ========
1113
+
1114
+ >>> from sympy import Symbol, hn1, hankel1, expand_func, yn, jn
1115
+ >>> z = Symbol("z")
1116
+ >>> nu = Symbol("nu", integer=True)
1117
+ >>> print(expand_func(hn1(nu, z)))
1118
+ jn(nu, z) + I*yn(nu, z)
1119
+ >>> print(expand_func(hn1(0, z)))
1120
+ sin(z)/z - I*cos(z)/z
1121
+ >>> print(expand_func(hn1(1, z)))
1122
+ -I*sin(z)/z - cos(z)/z + sin(z)/z**2 - I*cos(z)/z**2
1123
+ >>> hn1(nu, z).rewrite(jn)
1124
+ (-1)**(nu + 1)*I*jn(-nu - 1, z) + jn(nu, z)
1125
+ >>> hn1(nu, z).rewrite(yn)
1126
+ (-1)**nu*yn(-nu - 1, z) + I*yn(nu, z)
1127
+ >>> hn1(nu, z).rewrite(hankel1)
1128
+ sqrt(2)*sqrt(pi)*sqrt(1/z)*hankel1(nu, z)/2
1129
+
1130
+ See Also
1131
+ ========
1132
+
1133
+ hn2, jn, yn, hankel1, hankel2
1134
+
1135
+ References
1136
+ ==========
1137
+
1138
+ .. [1] https://dlmf.nist.gov/10.47
1139
+
1140
+ """
1141
+
1142
+ _hankel_kind_sign = S.One
1143
+
1144
+ @assume_integer_order
1145
+ def _eval_rewrite_as_hankel1(self, nu, z, **kwargs):
1146
+ return sqrt(pi/(2*z))*hankel1(nu, z)
1147
+
1148
+
1149
+ class hn2(SphericalHankelBase):
1150
+ r"""
1151
+ Spherical Hankel function of the second kind.
1152
+
1153
+ Explanation
1154
+ ===========
1155
+
1156
+ This function is defined as
1157
+
1158
+ .. math:: h_\nu^(2)(z) = j_\nu(z) - i y_\nu(z),
1159
+
1160
+ where $j_\nu(z)$ and $y_\nu(z)$ are the spherical
1161
+ Bessel function of the first and second kinds.
1162
+
1163
+ For integral orders $n$, $h_n^(2)$ is calculated using the formula:
1164
+
1165
+ .. math:: h_n^(2)(z) = j_{n} - i (-1)^{n+1} j_{-n-1}(z)
1166
+
1167
+ Examples
1168
+ ========
1169
+
1170
+ >>> from sympy import Symbol, hn2, hankel2, expand_func, jn, yn
1171
+ >>> z = Symbol("z")
1172
+ >>> nu = Symbol("nu", integer=True)
1173
+ >>> print(expand_func(hn2(nu, z)))
1174
+ jn(nu, z) - I*yn(nu, z)
1175
+ >>> print(expand_func(hn2(0, z)))
1176
+ sin(z)/z + I*cos(z)/z
1177
+ >>> print(expand_func(hn2(1, z)))
1178
+ I*sin(z)/z - cos(z)/z + sin(z)/z**2 + I*cos(z)/z**2
1179
+ >>> hn2(nu, z).rewrite(hankel2)
1180
+ sqrt(2)*sqrt(pi)*sqrt(1/z)*hankel2(nu, z)/2
1181
+ >>> hn2(nu, z).rewrite(jn)
1182
+ -(-1)**(nu + 1)*I*jn(-nu - 1, z) + jn(nu, z)
1183
+ >>> hn2(nu, z).rewrite(yn)
1184
+ (-1)**nu*yn(-nu - 1, z) - I*yn(nu, z)
1185
+
1186
+ See Also
1187
+ ========
1188
+
1189
+ hn1, jn, yn, hankel1, hankel2
1190
+
1191
+ References
1192
+ ==========
1193
+
1194
+ .. [1] https://dlmf.nist.gov/10.47
1195
+
1196
+ """
1197
+
1198
+ _hankel_kind_sign = -S.One
1199
+
1200
+ @assume_integer_order
1201
+ def _eval_rewrite_as_hankel2(self, nu, z, **kwargs):
1202
+ return sqrt(pi/(2*z))*hankel2(nu, z)
1203
+
1204
+
1205
+ def jn_zeros(n, k, method="sympy", dps=15):
1206
+ """
1207
+ Zeros of the spherical Bessel function of the first kind.
1208
+
1209
+ Explanation
1210
+ ===========
1211
+
1212
+ This returns an array of zeros of $jn$ up to the $k$-th zero.
1213
+
1214
+ * method = "sympy": uses `mpmath.besseljzero
1215
+ <https://mpmath.org/doc/current/functions/bessel.html#mpmath.besseljzero>`_
1216
+ * method = "scipy": uses the
1217
+ `SciPy's sph_jn <https://docs.scipy.org/doc/scipy/reference/generated/scipy.special.jn_zeros.html>`_
1218
+ and
1219
+ `newton <https://docs.scipy.org/doc/scipy/reference/generated/scipy.optimize.newton.html>`_
1220
+ to find all
1221
+ roots, which is faster than computing the zeros using a general
1222
+ numerical solver, but it requires SciPy and only works with low
1223
+ precision floating point numbers. (The function used with
1224
+ method="sympy" is a recent addition to mpmath; before that a general
1225
+ solver was used.)
1226
+
1227
+ Examples
1228
+ ========
1229
+
1230
+ >>> from sympy import jn_zeros
1231
+ >>> jn_zeros(2, 4, dps=5)
1232
+ [5.7635, 9.095, 12.323, 15.515]
1233
+
1234
+ See Also
1235
+ ========
1236
+
1237
+ jn, yn, besselj, besselk, bessely
1238
+
1239
+ Parameters
1240
+ ==========
1241
+
1242
+ n : integer
1243
+ order of Bessel function
1244
+
1245
+ k : integer
1246
+ number of zeros to return
1247
+
1248
+
1249
+ """
1250
+ from math import pi as math_pi
1251
+
1252
+ if method == "sympy":
1253
+ from mpmath import besseljzero
1254
+ from mpmath.libmp.libmpf import dps_to_prec
1255
+ prec = dps_to_prec(dps)
1256
+ return [Expr._from_mpmath(besseljzero(S(n + 0.5)._to_mpmath(prec),
1257
+ int(l)), prec)
1258
+ for l in range(1, k + 1)]
1259
+ elif method == "scipy":
1260
+ from scipy.optimize import newton
1261
+ try:
1262
+ from scipy.special import spherical_jn
1263
+ f = lambda x: spherical_jn(n, x)
1264
+ except ImportError:
1265
+ from scipy.special import sph_jn
1266
+ f = lambda x: sph_jn(n, x)[0][-1]
1267
+ else:
1268
+ raise NotImplementedError("Unknown method.")
1269
+
1270
+ def solver(f, x):
1271
+ if method == "scipy":
1272
+ root = newton(f, x)
1273
+ else:
1274
+ raise NotImplementedError("Unknown method.")
1275
+ return root
1276
+
1277
+ # we need to approximate the position of the first root:
1278
+ root = n + math_pi
1279
+ # determine the first root exactly:
1280
+ root = solver(f, root)
1281
+ roots = [root]
1282
+ for i in range(k - 1):
1283
+ # estimate the position of the next root using the last root + pi:
1284
+ root = solver(f, root + math_pi)
1285
+ roots.append(root)
1286
+ return roots
1287
+
1288
+
1289
+ class AiryBase(Function):
1290
+ """
1291
+ Abstract base class for Airy functions.
1292
+
1293
+ This class is meant to reduce code duplication.
1294
+
1295
+ """
1296
+
1297
+ def _eval_conjugate(self):
1298
+ return self.func(self.args[0].conjugate())
1299
+
1300
+ def _eval_is_extended_real(self):
1301
+ return self.args[0].is_extended_real
1302
+
1303
+ def as_real_imag(self, deep=True, **hints):
1304
+ z = self.args[0]
1305
+ zc = z.conjugate()
1306
+ f = self.func
1307
+ u = (f(z)+f(zc))/2
1308
+ v = I*(f(zc)-f(z))/2
1309
+ return u, v
1310
+
1311
+ def _eval_expand_complex(self, deep=True, **hints):
1312
+ re_part, im_part = self.as_real_imag(deep=deep, **hints)
1313
+ return re_part + im_part*I
1314
+
1315
+
1316
+ class airyai(AiryBase):
1317
+ r"""
1318
+ The Airy function $\operatorname{Ai}$ of the first kind.
1319
+
1320
+ Explanation
1321
+ ===========
1322
+
1323
+ The Airy function $\operatorname{Ai}(z)$ is defined to be the function
1324
+ satisfying Airy's differential equation
1325
+
1326
+ .. math::
1327
+ \frac{\mathrm{d}^2 w(z)}{\mathrm{d}z^2} - z w(z) = 0.
1328
+
1329
+ Equivalently, for real $z$
1330
+
1331
+ .. math::
1332
+ \operatorname{Ai}(z) := \frac{1}{\pi}
1333
+ \int_0^\infty \cos\left(\frac{t^3}{3} + z t\right) \mathrm{d}t.
1334
+
1335
+ Examples
1336
+ ========
1337
+
1338
+ Create an Airy function object:
1339
+
1340
+ >>> from sympy import airyai
1341
+ >>> from sympy.abc import z
1342
+
1343
+ >>> airyai(z)
1344
+ airyai(z)
1345
+
1346
+ Several special values are known:
1347
+
1348
+ >>> airyai(0)
1349
+ 3**(1/3)/(3*gamma(2/3))
1350
+ >>> from sympy import oo
1351
+ >>> airyai(oo)
1352
+ 0
1353
+ >>> airyai(-oo)
1354
+ 0
1355
+
1356
+ The Airy function obeys the mirror symmetry:
1357
+
1358
+ >>> from sympy import conjugate
1359
+ >>> conjugate(airyai(z))
1360
+ airyai(conjugate(z))
1361
+
1362
+ Differentiation with respect to $z$ is supported:
1363
+
1364
+ >>> from sympy import diff
1365
+ >>> diff(airyai(z), z)
1366
+ airyaiprime(z)
1367
+ >>> diff(airyai(z), z, 2)
1368
+ z*airyai(z)
1369
+
1370
+ Series expansion is also supported:
1371
+
1372
+ >>> from sympy import series
1373
+ >>> series(airyai(z), z, 0, 3)
1374
+ 3**(5/6)*gamma(1/3)/(6*pi) - 3**(1/6)*z*gamma(2/3)/(2*pi) + O(z**3)
1375
+
1376
+ We can numerically evaluate the Airy function to arbitrary precision
1377
+ on the whole complex plane:
1378
+
1379
+ >>> airyai(-2).evalf(50)
1380
+ 0.22740742820168557599192443603787379946077222541710
1381
+
1382
+ Rewrite $\operatorname{Ai}(z)$ in terms of hypergeometric functions:
1383
+
1384
+ >>> from sympy import hyper
1385
+ >>> airyai(z).rewrite(hyper)
1386
+ -3**(2/3)*z*hyper((), (4/3,), z**3/9)/(3*gamma(1/3)) + 3**(1/3)*hyper((), (2/3,), z**3/9)/(3*gamma(2/3))
1387
+
1388
+ See Also
1389
+ ========
1390
+
1391
+ airybi: Airy function of the second kind.
1392
+ airyaiprime: Derivative of the Airy function of the first kind.
1393
+ airybiprime: Derivative of the Airy function of the second kind.
1394
+
1395
+ References
1396
+ ==========
1397
+
1398
+ .. [1] https://en.wikipedia.org/wiki/Airy_function
1399
+ .. [2] https://dlmf.nist.gov/9
1400
+ .. [3] https://encyclopediaofmath.org/wiki/Airy_functions
1401
+ .. [4] https://mathworld.wolfram.com/AiryFunctions.html
1402
+
1403
+ """
1404
+
1405
+ nargs = 1
1406
+ unbranched = True
1407
+
1408
+ @classmethod
1409
+ def eval(cls, arg):
1410
+ if arg.is_Number:
1411
+ if arg is S.NaN:
1412
+ return S.NaN
1413
+ elif arg is S.Infinity:
1414
+ return S.Zero
1415
+ elif arg is S.NegativeInfinity:
1416
+ return S.Zero
1417
+ elif arg.is_zero:
1418
+ return S.One / (3**Rational(2, 3) * gamma(Rational(2, 3)))
1419
+ if arg.is_zero:
1420
+ return S.One / (3**Rational(2, 3) * gamma(Rational(2, 3)))
1421
+
1422
+ def fdiff(self, argindex=1):
1423
+ if argindex == 1:
1424
+ return airyaiprime(self.args[0])
1425
+ else:
1426
+ raise ArgumentIndexError(self, argindex)
1427
+
1428
+ @staticmethod
1429
+ @cacheit
1430
+ def taylor_term(n, x, *previous_terms):
1431
+ if n < 0:
1432
+ return S.Zero
1433
+ else:
1434
+ x = sympify(x)
1435
+ if len(previous_terms) > 1:
1436
+ p = previous_terms[-1]
1437
+ return ((cbrt(3)*x)**(-n)*(cbrt(3)*x)**(n + 1)*sin(pi*(n*Rational(2, 3) + Rational(4, 3)))*factorial(n) *
1438
+ gamma(n/3 + Rational(2, 3))/(sin(pi*(n*Rational(2, 3) + Rational(2, 3)))*factorial(n + 1)*gamma(n/3 + Rational(1, 3))) * p)
1439
+ else:
1440
+ return (S.One/(3**Rational(2, 3)*pi) * gamma((n+S.One)/S(3)) * sin(Rational(2, 3)*pi*(n+S.One)) /
1441
+ factorial(n) * (cbrt(3)*x)**n)
1442
+
1443
+ def _eval_rewrite_as_besselj(self, z, **kwargs):
1444
+ ot = Rational(1, 3)
1445
+ tt = Rational(2, 3)
1446
+ a = Pow(-z, Rational(3, 2))
1447
+ if re(z).is_negative:
1448
+ return ot*sqrt(-z) * (besselj(-ot, tt*a) + besselj(ot, tt*a))
1449
+
1450
+ def _eval_rewrite_as_besseli(self, z, **kwargs):
1451
+ ot = Rational(1, 3)
1452
+ tt = Rational(2, 3)
1453
+ a = Pow(z, Rational(3, 2))
1454
+ if re(z).is_positive:
1455
+ return ot*sqrt(z) * (besseli(-ot, tt*a) - besseli(ot, tt*a))
1456
+ else:
1457
+ return ot*(Pow(a, ot)*besseli(-ot, tt*a) - z*Pow(a, -ot)*besseli(ot, tt*a))
1458
+
1459
+ def _eval_rewrite_as_hyper(self, z, **kwargs):
1460
+ pf1 = S.One / (3**Rational(2, 3)*gamma(Rational(2, 3)))
1461
+ pf2 = z / (root(3, 3)*gamma(Rational(1, 3)))
1462
+ return pf1 * hyper([], [Rational(2, 3)], z**3/9) - pf2 * hyper([], [Rational(4, 3)], z**3/9)
1463
+
1464
+ def _eval_expand_func(self, **hints):
1465
+ arg = self.args[0]
1466
+ symbs = arg.free_symbols
1467
+
1468
+ if len(symbs) == 1:
1469
+ z = symbs.pop()
1470
+ c = Wild("c", exclude=[z])
1471
+ d = Wild("d", exclude=[z])
1472
+ m = Wild("m", exclude=[z])
1473
+ n = Wild("n", exclude=[z])
1474
+ M = arg.match(c*(d*z**n)**m)
1475
+ if M is not None:
1476
+ m = M[m]
1477
+ # The transformation is given by 03.05.16.0001.01
1478
+ # https://functions.wolfram.com/Bessel-TypeFunctions/AiryAi/16/01/01/0001/
1479
+ if (3*m).is_integer:
1480
+ c = M[c]
1481
+ d = M[d]
1482
+ n = M[n]
1483
+ pf = (d * z**n)**m / (d**m * z**(m*n))
1484
+ newarg = c * d**m * z**(m*n)
1485
+ return S.Half * ((pf + S.One)*airyai(newarg) - (pf - S.One)/sqrt(3)*airybi(newarg))
1486
+
1487
+
1488
+ class airybi(AiryBase):
1489
+ r"""
1490
+ The Airy function $\operatorname{Bi}$ of the second kind.
1491
+
1492
+ Explanation
1493
+ ===========
1494
+
1495
+ The Airy function $\operatorname{Bi}(z)$ is defined to be the function
1496
+ satisfying Airy's differential equation
1497
+
1498
+ .. math::
1499
+ \frac{\mathrm{d}^2 w(z)}{\mathrm{d}z^2} - z w(z) = 0.
1500
+
1501
+ Equivalently, for real $z$
1502
+
1503
+ .. math::
1504
+ \operatorname{Bi}(z) := \frac{1}{\pi}
1505
+ \int_0^\infty
1506
+ \exp\left(-\frac{t^3}{3} + z t\right)
1507
+ + \sin\left(\frac{t^3}{3} + z t\right) \mathrm{d}t.
1508
+
1509
+ Examples
1510
+ ========
1511
+
1512
+ Create an Airy function object:
1513
+
1514
+ >>> from sympy import airybi
1515
+ >>> from sympy.abc import z
1516
+
1517
+ >>> airybi(z)
1518
+ airybi(z)
1519
+
1520
+ Several special values are known:
1521
+
1522
+ >>> airybi(0)
1523
+ 3**(5/6)/(3*gamma(2/3))
1524
+ >>> from sympy import oo
1525
+ >>> airybi(oo)
1526
+ oo
1527
+ >>> airybi(-oo)
1528
+ 0
1529
+
1530
+ The Airy function obeys the mirror symmetry:
1531
+
1532
+ >>> from sympy import conjugate
1533
+ >>> conjugate(airybi(z))
1534
+ airybi(conjugate(z))
1535
+
1536
+ Differentiation with respect to $z$ is supported:
1537
+
1538
+ >>> from sympy import diff
1539
+ >>> diff(airybi(z), z)
1540
+ airybiprime(z)
1541
+ >>> diff(airybi(z), z, 2)
1542
+ z*airybi(z)
1543
+
1544
+ Series expansion is also supported:
1545
+
1546
+ >>> from sympy import series
1547
+ >>> series(airybi(z), z, 0, 3)
1548
+ 3**(1/3)*gamma(1/3)/(2*pi) + 3**(2/3)*z*gamma(2/3)/(2*pi) + O(z**3)
1549
+
1550
+ We can numerically evaluate the Airy function to arbitrary precision
1551
+ on the whole complex plane:
1552
+
1553
+ >>> airybi(-2).evalf(50)
1554
+ -0.41230258795639848808323405461146104203453483447240
1555
+
1556
+ Rewrite $\operatorname{Bi}(z)$ in terms of hypergeometric functions:
1557
+
1558
+ >>> from sympy import hyper
1559
+ >>> airybi(z).rewrite(hyper)
1560
+ 3**(1/6)*z*hyper((), (4/3,), z**3/9)/gamma(1/3) + 3**(5/6)*hyper((), (2/3,), z**3/9)/(3*gamma(2/3))
1561
+
1562
+ See Also
1563
+ ========
1564
+
1565
+ airyai: Airy function of the first kind.
1566
+ airyaiprime: Derivative of the Airy function of the first kind.
1567
+ airybiprime: Derivative of the Airy function of the second kind.
1568
+
1569
+ References
1570
+ ==========
1571
+
1572
+ .. [1] https://en.wikipedia.org/wiki/Airy_function
1573
+ .. [2] https://dlmf.nist.gov/9
1574
+ .. [3] https://encyclopediaofmath.org/wiki/Airy_functions
1575
+ .. [4] https://mathworld.wolfram.com/AiryFunctions.html
1576
+
1577
+ """
1578
+
1579
+ nargs = 1
1580
+ unbranched = True
1581
+
1582
+ @classmethod
1583
+ def eval(cls, arg):
1584
+ if arg.is_Number:
1585
+ if arg is S.NaN:
1586
+ return S.NaN
1587
+ elif arg is S.Infinity:
1588
+ return S.Infinity
1589
+ elif arg is S.NegativeInfinity:
1590
+ return S.Zero
1591
+ elif arg.is_zero:
1592
+ return S.One / (3**Rational(1, 6) * gamma(Rational(2, 3)))
1593
+
1594
+ if arg.is_zero:
1595
+ return S.One / (3**Rational(1, 6) * gamma(Rational(2, 3)))
1596
+
1597
+ def fdiff(self, argindex=1):
1598
+ if argindex == 1:
1599
+ return airybiprime(self.args[0])
1600
+ else:
1601
+ raise ArgumentIndexError(self, argindex)
1602
+
1603
+ @staticmethod
1604
+ @cacheit
1605
+ def taylor_term(n, x, *previous_terms):
1606
+ if n < 0:
1607
+ return S.Zero
1608
+ else:
1609
+ x = sympify(x)
1610
+ if len(previous_terms) > 1:
1611
+ p = previous_terms[-1]
1612
+ return (cbrt(3)*x * Abs(sin(Rational(2, 3)*pi*(n + S.One))) * factorial((n - S.One)/S(3)) /
1613
+ ((n + S.One) * Abs(cos(Rational(2, 3)*pi*(n + S.Half))) * factorial((n - 2)/S(3))) * p)
1614
+ else:
1615
+ return (S.One/(root(3, 6)*pi) * gamma((n + S.One)/S(3)) * Abs(sin(Rational(2, 3)*pi*(n + S.One))) /
1616
+ factorial(n) * (cbrt(3)*x)**n)
1617
+
1618
+ def _eval_rewrite_as_besselj(self, z, **kwargs):
1619
+ ot = Rational(1, 3)
1620
+ tt = Rational(2, 3)
1621
+ a = Pow(-z, Rational(3, 2))
1622
+ if re(z).is_negative:
1623
+ return sqrt(-z/3) * (besselj(-ot, tt*a) - besselj(ot, tt*a))
1624
+
1625
+ def _eval_rewrite_as_besseli(self, z, **kwargs):
1626
+ ot = Rational(1, 3)
1627
+ tt = Rational(2, 3)
1628
+ a = Pow(z, Rational(3, 2))
1629
+ if re(z).is_positive:
1630
+ return sqrt(z)/sqrt(3) * (besseli(-ot, tt*a) + besseli(ot, tt*a))
1631
+ else:
1632
+ b = Pow(a, ot)
1633
+ c = Pow(a, -ot)
1634
+ return sqrt(ot)*(b*besseli(-ot, tt*a) + z*c*besseli(ot, tt*a))
1635
+
1636
+ def _eval_rewrite_as_hyper(self, z, **kwargs):
1637
+ pf1 = S.One / (root(3, 6)*gamma(Rational(2, 3)))
1638
+ pf2 = z*root(3, 6) / gamma(Rational(1, 3))
1639
+ return pf1 * hyper([], [Rational(2, 3)], z**3/9) + pf2 * hyper([], [Rational(4, 3)], z**3/9)
1640
+
1641
+ def _eval_expand_func(self, **hints):
1642
+ arg = self.args[0]
1643
+ symbs = arg.free_symbols
1644
+
1645
+ if len(symbs) == 1:
1646
+ z = symbs.pop()
1647
+ c = Wild("c", exclude=[z])
1648
+ d = Wild("d", exclude=[z])
1649
+ m = Wild("m", exclude=[z])
1650
+ n = Wild("n", exclude=[z])
1651
+ M = arg.match(c*(d*z**n)**m)
1652
+ if M is not None:
1653
+ m = M[m]
1654
+ # The transformation is given by 03.06.16.0001.01
1655
+ # https://functions.wolfram.com/Bessel-TypeFunctions/AiryBi/16/01/01/0001/
1656
+ if (3*m).is_integer:
1657
+ c = M[c]
1658
+ d = M[d]
1659
+ n = M[n]
1660
+ pf = (d * z**n)**m / (d**m * z**(m*n))
1661
+ newarg = c * d**m * z**(m*n)
1662
+ return S.Half * (sqrt(3)*(S.One - pf)*airyai(newarg) + (S.One + pf)*airybi(newarg))
1663
+
1664
+
1665
+ class airyaiprime(AiryBase):
1666
+ r"""
1667
+ The derivative $\operatorname{Ai}^\prime$ of the Airy function of the first
1668
+ kind.
1669
+
1670
+ Explanation
1671
+ ===========
1672
+
1673
+ The Airy function $\operatorname{Ai}^\prime(z)$ is defined to be the
1674
+ function
1675
+
1676
+ .. math::
1677
+ \operatorname{Ai}^\prime(z) := \frac{\mathrm{d} \operatorname{Ai}(z)}{\mathrm{d} z}.
1678
+
1679
+ Examples
1680
+ ========
1681
+
1682
+ Create an Airy function object:
1683
+
1684
+ >>> from sympy import airyaiprime
1685
+ >>> from sympy.abc import z
1686
+
1687
+ >>> airyaiprime(z)
1688
+ airyaiprime(z)
1689
+
1690
+ Several special values are known:
1691
+
1692
+ >>> airyaiprime(0)
1693
+ -3**(2/3)/(3*gamma(1/3))
1694
+ >>> from sympy import oo
1695
+ >>> airyaiprime(oo)
1696
+ 0
1697
+
1698
+ The Airy function obeys the mirror symmetry:
1699
+
1700
+ >>> from sympy import conjugate
1701
+ >>> conjugate(airyaiprime(z))
1702
+ airyaiprime(conjugate(z))
1703
+
1704
+ Differentiation with respect to $z$ is supported:
1705
+
1706
+ >>> from sympy import diff
1707
+ >>> diff(airyaiprime(z), z)
1708
+ z*airyai(z)
1709
+ >>> diff(airyaiprime(z), z, 2)
1710
+ z*airyaiprime(z) + airyai(z)
1711
+
1712
+ Series expansion is also supported:
1713
+
1714
+ >>> from sympy import series
1715
+ >>> series(airyaiprime(z), z, 0, 3)
1716
+ -3**(2/3)/(3*gamma(1/3)) + 3**(1/3)*z**2/(6*gamma(2/3)) + O(z**3)
1717
+
1718
+ We can numerically evaluate the Airy function to arbitrary precision
1719
+ on the whole complex plane:
1720
+
1721
+ >>> airyaiprime(-2).evalf(50)
1722
+ 0.61825902074169104140626429133247528291577794512415
1723
+
1724
+ Rewrite $\operatorname{Ai}^\prime(z)$ in terms of hypergeometric functions:
1725
+
1726
+ >>> from sympy import hyper
1727
+ >>> airyaiprime(z).rewrite(hyper)
1728
+ 3**(1/3)*z**2*hyper((), (5/3,), z**3/9)/(6*gamma(2/3)) - 3**(2/3)*hyper((), (1/3,), z**3/9)/(3*gamma(1/3))
1729
+
1730
+ See Also
1731
+ ========
1732
+
1733
+ airyai: Airy function of the first kind.
1734
+ airybi: Airy function of the second kind.
1735
+ airybiprime: Derivative of the Airy function of the second kind.
1736
+
1737
+ References
1738
+ ==========
1739
+
1740
+ .. [1] https://en.wikipedia.org/wiki/Airy_function
1741
+ .. [2] https://dlmf.nist.gov/9
1742
+ .. [3] https://encyclopediaofmath.org/wiki/Airy_functions
1743
+ .. [4] https://mathworld.wolfram.com/AiryFunctions.html
1744
+
1745
+ """
1746
+
1747
+ nargs = 1
1748
+ unbranched = True
1749
+
1750
+ @classmethod
1751
+ def eval(cls, arg):
1752
+ if arg.is_Number:
1753
+ if arg is S.NaN:
1754
+ return S.NaN
1755
+ elif arg is S.Infinity:
1756
+ return S.Zero
1757
+
1758
+ if arg.is_zero:
1759
+ return S.NegativeOne / (3**Rational(1, 3) * gamma(Rational(1, 3)))
1760
+
1761
+ def fdiff(self, argindex=1):
1762
+ if argindex == 1:
1763
+ return self.args[0]*airyai(self.args[0])
1764
+ else:
1765
+ raise ArgumentIndexError(self, argindex)
1766
+
1767
+ def _eval_evalf(self, prec):
1768
+ z = self.args[0]._to_mpmath(prec)
1769
+ with workprec(prec):
1770
+ res = mp.airyai(z, derivative=1)
1771
+ return Expr._from_mpmath(res, prec)
1772
+
1773
+ def _eval_rewrite_as_besselj(self, z, **kwargs):
1774
+ tt = Rational(2, 3)
1775
+ a = Pow(-z, Rational(3, 2))
1776
+ if re(z).is_negative:
1777
+ return z/3 * (besselj(-tt, tt*a) - besselj(tt, tt*a))
1778
+
1779
+ def _eval_rewrite_as_besseli(self, z, **kwargs):
1780
+ ot = Rational(1, 3)
1781
+ tt = Rational(2, 3)
1782
+ a = tt * Pow(z, Rational(3, 2))
1783
+ if re(z).is_positive:
1784
+ return z/3 * (besseli(tt, a) - besseli(-tt, a))
1785
+ else:
1786
+ a = Pow(z, Rational(3, 2))
1787
+ b = Pow(a, tt)
1788
+ c = Pow(a, -tt)
1789
+ return ot * (z**2*c*besseli(tt, tt*a) - b*besseli(-ot, tt*a))
1790
+
1791
+ def _eval_rewrite_as_hyper(self, z, **kwargs):
1792
+ pf1 = z**2 / (2*3**Rational(2, 3)*gamma(Rational(2, 3)))
1793
+ pf2 = 1 / (root(3, 3)*gamma(Rational(1, 3)))
1794
+ return pf1 * hyper([], [Rational(5, 3)], z**3/9) - pf2 * hyper([], [Rational(1, 3)], z**3/9)
1795
+
1796
+ def _eval_expand_func(self, **hints):
1797
+ arg = self.args[0]
1798
+ symbs = arg.free_symbols
1799
+
1800
+ if len(symbs) == 1:
1801
+ z = symbs.pop()
1802
+ c = Wild("c", exclude=[z])
1803
+ d = Wild("d", exclude=[z])
1804
+ m = Wild("m", exclude=[z])
1805
+ n = Wild("n", exclude=[z])
1806
+ M = arg.match(c*(d*z**n)**m)
1807
+ if M is not None:
1808
+ m = M[m]
1809
+ # The transformation is in principle
1810
+ # given by 03.07.16.0001.01 but note
1811
+ # that there is an error in this formula.
1812
+ # https://functions.wolfram.com/Bessel-TypeFunctions/AiryAiPrime/16/01/01/0001/
1813
+ if (3*m).is_integer:
1814
+ c = M[c]
1815
+ d = M[d]
1816
+ n = M[n]
1817
+ pf = (d**m * z**(n*m)) / (d * z**n)**m
1818
+ newarg = c * d**m * z**(n*m)
1819
+ return S.Half * ((pf + S.One)*airyaiprime(newarg) + (pf - S.One)/sqrt(3)*airybiprime(newarg))
1820
+
1821
+
1822
+ class airybiprime(AiryBase):
1823
+ r"""
1824
+ The derivative $\operatorname{Bi}^\prime$ of the Airy function of the first
1825
+ kind.
1826
+
1827
+ Explanation
1828
+ ===========
1829
+
1830
+ The Airy function $\operatorname{Bi}^\prime(z)$ is defined to be the
1831
+ function
1832
+
1833
+ .. math::
1834
+ \operatorname{Bi}^\prime(z) := \frac{\mathrm{d} \operatorname{Bi}(z)}{\mathrm{d} z}.
1835
+
1836
+ Examples
1837
+ ========
1838
+
1839
+ Create an Airy function object:
1840
+
1841
+ >>> from sympy import airybiprime
1842
+ >>> from sympy.abc import z
1843
+
1844
+ >>> airybiprime(z)
1845
+ airybiprime(z)
1846
+
1847
+ Several special values are known:
1848
+
1849
+ >>> airybiprime(0)
1850
+ 3**(1/6)/gamma(1/3)
1851
+ >>> from sympy import oo
1852
+ >>> airybiprime(oo)
1853
+ oo
1854
+ >>> airybiprime(-oo)
1855
+ 0
1856
+
1857
+ The Airy function obeys the mirror symmetry:
1858
+
1859
+ >>> from sympy import conjugate
1860
+ >>> conjugate(airybiprime(z))
1861
+ airybiprime(conjugate(z))
1862
+
1863
+ Differentiation with respect to $z$ is supported:
1864
+
1865
+ >>> from sympy import diff
1866
+ >>> diff(airybiprime(z), z)
1867
+ z*airybi(z)
1868
+ >>> diff(airybiprime(z), z, 2)
1869
+ z*airybiprime(z) + airybi(z)
1870
+
1871
+ Series expansion is also supported:
1872
+
1873
+ >>> from sympy import series
1874
+ >>> series(airybiprime(z), z, 0, 3)
1875
+ 3**(1/6)/gamma(1/3) + 3**(5/6)*z**2/(6*gamma(2/3)) + O(z**3)
1876
+
1877
+ We can numerically evaluate the Airy function to arbitrary precision
1878
+ on the whole complex plane:
1879
+
1880
+ >>> airybiprime(-2).evalf(50)
1881
+ 0.27879516692116952268509756941098324140300059345163
1882
+
1883
+ Rewrite $\operatorname{Bi}^\prime(z)$ in terms of hypergeometric functions:
1884
+
1885
+ >>> from sympy import hyper
1886
+ >>> airybiprime(z).rewrite(hyper)
1887
+ 3**(5/6)*z**2*hyper((), (5/3,), z**3/9)/(6*gamma(2/3)) + 3**(1/6)*hyper((), (1/3,), z**3/9)/gamma(1/3)
1888
+
1889
+ See Also
1890
+ ========
1891
+
1892
+ airyai: Airy function of the first kind.
1893
+ airybi: Airy function of the second kind.
1894
+ airyaiprime: Derivative of the Airy function of the first kind.
1895
+
1896
+ References
1897
+ ==========
1898
+
1899
+ .. [1] https://en.wikipedia.org/wiki/Airy_function
1900
+ .. [2] https://dlmf.nist.gov/9
1901
+ .. [3] https://encyclopediaofmath.org/wiki/Airy_functions
1902
+ .. [4] https://mathworld.wolfram.com/AiryFunctions.html
1903
+
1904
+ """
1905
+
1906
+ nargs = 1
1907
+ unbranched = True
1908
+
1909
+ @classmethod
1910
+ def eval(cls, arg):
1911
+ if arg.is_Number:
1912
+ if arg is S.NaN:
1913
+ return S.NaN
1914
+ elif arg is S.Infinity:
1915
+ return S.Infinity
1916
+ elif arg is S.NegativeInfinity:
1917
+ return S.Zero
1918
+ elif arg.is_zero:
1919
+ return 3**Rational(1, 6) / gamma(Rational(1, 3))
1920
+
1921
+ if arg.is_zero:
1922
+ return 3**Rational(1, 6) / gamma(Rational(1, 3))
1923
+
1924
+
1925
+ def fdiff(self, argindex=1):
1926
+ if argindex == 1:
1927
+ return self.args[0]*airybi(self.args[0])
1928
+ else:
1929
+ raise ArgumentIndexError(self, argindex)
1930
+
1931
+ def _eval_evalf(self, prec):
1932
+ z = self.args[0]._to_mpmath(prec)
1933
+ with workprec(prec):
1934
+ res = mp.airybi(z, derivative=1)
1935
+ return Expr._from_mpmath(res, prec)
1936
+
1937
+ def _eval_rewrite_as_besselj(self, z, **kwargs):
1938
+ tt = Rational(2, 3)
1939
+ a = tt * Pow(-z, Rational(3, 2))
1940
+ if re(z).is_negative:
1941
+ return -z/sqrt(3) * (besselj(-tt, a) + besselj(tt, a))
1942
+
1943
+ def _eval_rewrite_as_besseli(self, z, **kwargs):
1944
+ ot = Rational(1, 3)
1945
+ tt = Rational(2, 3)
1946
+ a = tt * Pow(z, Rational(3, 2))
1947
+ if re(z).is_positive:
1948
+ return z/sqrt(3) * (besseli(-tt, a) + besseli(tt, a))
1949
+ else:
1950
+ a = Pow(z, Rational(3, 2))
1951
+ b = Pow(a, tt)
1952
+ c = Pow(a, -tt)
1953
+ return sqrt(ot) * (b*besseli(-tt, tt*a) + z**2*c*besseli(tt, tt*a))
1954
+
1955
+ def _eval_rewrite_as_hyper(self, z, **kwargs):
1956
+ pf1 = z**2 / (2*root(3, 6)*gamma(Rational(2, 3)))
1957
+ pf2 = root(3, 6) / gamma(Rational(1, 3))
1958
+ return pf1 * hyper([], [Rational(5, 3)], z**3/9) + pf2 * hyper([], [Rational(1, 3)], z**3/9)
1959
+
1960
+ def _eval_expand_func(self, **hints):
1961
+ arg = self.args[0]
1962
+ symbs = arg.free_symbols
1963
+
1964
+ if len(symbs) == 1:
1965
+ z = symbs.pop()
1966
+ c = Wild("c", exclude=[z])
1967
+ d = Wild("d", exclude=[z])
1968
+ m = Wild("m", exclude=[z])
1969
+ n = Wild("n", exclude=[z])
1970
+ M = arg.match(c*(d*z**n)**m)
1971
+ if M is not None:
1972
+ m = M[m]
1973
+ # The transformation is in principle
1974
+ # given by 03.08.16.0001.01 but note
1975
+ # that there is an error in this formula.
1976
+ # https://functions.wolfram.com/Bessel-TypeFunctions/AiryBiPrime/16/01/01/0001/
1977
+ if (3*m).is_integer:
1978
+ c = M[c]
1979
+ d = M[d]
1980
+ n = M[n]
1981
+ pf = (d**m * z**(n*m)) / (d * z**n)**m
1982
+ newarg = c * d**m * z**(n*m)
1983
+ return S.Half * (sqrt(3)*(pf - S.One)*airyaiprime(newarg) + (pf + S.One)*airybiprime(newarg))
1984
+
1985
+
1986
+ class marcumq(Function):
1987
+ r"""
1988
+ The Marcum Q-function.
1989
+
1990
+ Explanation
1991
+ ===========
1992
+
1993
+ The Marcum Q-function is defined by the meromorphic continuation of
1994
+
1995
+ .. math::
1996
+ Q_m(a, b) = a^{- m + 1} \int_{b}^{\infty} x^{m} e^{- \frac{a^{2}}{2} - \frac{x^{2}}{2}} I_{m - 1}\left(a x\right)\, dx
1997
+
1998
+ Examples
1999
+ ========
2000
+
2001
+ >>> from sympy import marcumq
2002
+ >>> from sympy.abc import m, a, b
2003
+ >>> marcumq(m, a, b)
2004
+ marcumq(m, a, b)
2005
+
2006
+ Special values:
2007
+
2008
+ >>> marcumq(m, 0, b)
2009
+ uppergamma(m, b**2/2)/gamma(m)
2010
+ >>> marcumq(0, 0, 0)
2011
+ 0
2012
+ >>> marcumq(0, a, 0)
2013
+ 1 - exp(-a**2/2)
2014
+ >>> marcumq(1, a, a)
2015
+ 1/2 + exp(-a**2)*besseli(0, a**2)/2
2016
+ >>> marcumq(2, a, a)
2017
+ 1/2 + exp(-a**2)*besseli(0, a**2)/2 + exp(-a**2)*besseli(1, a**2)
2018
+
2019
+ Differentiation with respect to $a$ and $b$ is supported:
2020
+
2021
+ >>> from sympy import diff
2022
+ >>> diff(marcumq(m, a, b), a)
2023
+ a*(-marcumq(m, a, b) + marcumq(m + 1, a, b))
2024
+ >>> diff(marcumq(m, a, b), b)
2025
+ -a**(1 - m)*b**m*exp(-a**2/2 - b**2/2)*besseli(m - 1, a*b)
2026
+
2027
+ References
2028
+ ==========
2029
+
2030
+ .. [1] https://en.wikipedia.org/wiki/Marcum_Q-function
2031
+ .. [2] https://mathworld.wolfram.com/MarcumQ-Function.html
2032
+
2033
+ """
2034
+
2035
+ @classmethod
2036
+ def eval(cls, m, a, b):
2037
+ if a is S.Zero:
2038
+ if m is S.Zero and b is S.Zero:
2039
+ return S.Zero
2040
+ return uppergamma(m, b**2 * S.Half) / gamma(m)
2041
+
2042
+ if m is S.Zero and b is S.Zero:
2043
+ return 1 - 1 / exp(a**2 * S.Half)
2044
+
2045
+ if a == b:
2046
+ if m is S.One:
2047
+ return (1 + exp(-a**2) * besseli(0, a**2))*S.Half
2048
+ if m == 2:
2049
+ return S.Half + S.Half * exp(-a**2) * besseli(0, a**2) + exp(-a**2) * besseli(1, a**2)
2050
+
2051
+ if a.is_zero:
2052
+ if m.is_zero and b.is_zero:
2053
+ return S.Zero
2054
+ return uppergamma(m, b**2*S.Half) / gamma(m)
2055
+
2056
+ if m.is_zero and b.is_zero:
2057
+ return 1 - 1 / exp(a**2*S.Half)
2058
+
2059
+ def fdiff(self, argindex=2):
2060
+ m, a, b = self.args
2061
+ if argindex == 2:
2062
+ return a * (-marcumq(m, a, b) + marcumq(1+m, a, b))
2063
+ elif argindex == 3:
2064
+ return (-b**m / a**(m-1)) * exp(-(a**2 + b**2)/2) * besseli(m-1, a*b)
2065
+ else:
2066
+ raise ArgumentIndexError(self, argindex)
2067
+
2068
+ def _eval_rewrite_as_Integral(self, m, a, b, **kwargs):
2069
+ from sympy.integrals.integrals import Integral
2070
+ x = kwargs.get('x', Dummy('x'))
2071
+ return a ** (1 - m) * \
2072
+ Integral(x**m * exp(-(x**2 + a**2)/2) * besseli(m-1, a*x), [x, b, S.Infinity])
2073
+
2074
+ def _eval_rewrite_as_Sum(self, m, a, b, **kwargs):
2075
+ from sympy.concrete.summations import Sum
2076
+ k = kwargs.get('k', Dummy('k'))
2077
+ return exp(-(a**2 + b**2) / 2) * Sum((a/b)**k * besseli(k, a*b), [k, 1-m, S.Infinity])
2078
+
2079
+ def _eval_rewrite_as_besseli(self, m, a, b, **kwargs):
2080
+ if a == b:
2081
+ if m == 1:
2082
+ return (1 + exp(-a**2) * besseli(0, a**2)) / 2
2083
+ if m.is_Integer and m >= 2:
2084
+ s = sum([besseli(i, a**2) for i in range(1, m)])
2085
+ return S.Half + exp(-a**2) * besseli(0, a**2) / 2 + exp(-a**2) * s
2086
+
2087
+ def _eval_is_zero(self):
2088
+ if all(arg.is_zero for arg in self.args):
2089
+ return True
env-llmeval/lib/python3.10/site-packages/sympy/functions/special/beta_functions.py ADDED
@@ -0,0 +1,389 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ from sympy.core import S
2
+ from sympy.core.function import Function, ArgumentIndexError
3
+ from sympy.core.symbol import Dummy
4
+ from sympy.functions.special.gamma_functions import gamma, digamma
5
+ from sympy.functions.combinatorial.numbers import catalan
6
+ from sympy.functions.elementary.complexes import conjugate
7
+
8
+ # See mpmath #569 and SymPy #20569
9
+ def betainc_mpmath_fix(a, b, x1, x2, reg=0):
10
+ from mpmath import betainc, mpf
11
+ if x1 == x2:
12
+ return mpf(0)
13
+ else:
14
+ return betainc(a, b, x1, x2, reg)
15
+
16
+ ###############################################################################
17
+ ############################ COMPLETE BETA FUNCTION ##########################
18
+ ###############################################################################
19
+
20
+ class beta(Function):
21
+ r"""
22
+ The beta integral is called the Eulerian integral of the first kind by
23
+ Legendre:
24
+
25
+ .. math::
26
+ \mathrm{B}(x,y) \int^{1}_{0} t^{x-1} (1-t)^{y-1} \mathrm{d}t.
27
+
28
+ Explanation
29
+ ===========
30
+
31
+ The Beta function or Euler's first integral is closely associated
32
+ with the gamma function. The Beta function is often used in probability
33
+ theory and mathematical statistics. It satisfies properties like:
34
+
35
+ .. math::
36
+ \mathrm{B}(a,1) = \frac{1}{a} \\
37
+ \mathrm{B}(a,b) = \mathrm{B}(b,a) \\
38
+ \mathrm{B}(a,b) = \frac{\Gamma(a) \Gamma(b)}{\Gamma(a+b)}
39
+
40
+ Therefore for integral values of $a$ and $b$:
41
+
42
+ .. math::
43
+ \mathrm{B} = \frac{(a-1)! (b-1)!}{(a+b-1)!}
44
+
45
+ A special case of the Beta function when `x = y` is the
46
+ Central Beta function. It satisfies properties like:
47
+
48
+ .. math::
49
+ \mathrm{B}(x) = 2^{1 - 2x}\mathrm{B}(x, \frac{1}{2})
50
+ \mathrm{B}(x) = 2^{1 - 2x} cos(\pi x) \mathrm{B}(\frac{1}{2} - x, x)
51
+ \mathrm{B}(x) = \int_{0}^{1} \frac{t^x}{(1 + t)^{2x}} dt
52
+ \mathrm{B}(x) = \frac{2}{x} \prod_{n = 1}^{\infty} \frac{n(n + 2x)}{(n + x)^2}
53
+
54
+ Examples
55
+ ========
56
+
57
+ >>> from sympy import I, pi
58
+ >>> from sympy.abc import x, y
59
+
60
+ The Beta function obeys the mirror symmetry:
61
+
62
+ >>> from sympy import beta, conjugate
63
+ >>> conjugate(beta(x, y))
64
+ beta(conjugate(x), conjugate(y))
65
+
66
+ Differentiation with respect to both $x$ and $y$ is supported:
67
+
68
+ >>> from sympy import beta, diff
69
+ >>> diff(beta(x, y), x)
70
+ (polygamma(0, x) - polygamma(0, x + y))*beta(x, y)
71
+
72
+ >>> diff(beta(x, y), y)
73
+ (polygamma(0, y) - polygamma(0, x + y))*beta(x, y)
74
+
75
+ >>> diff(beta(x), x)
76
+ 2*(polygamma(0, x) - polygamma(0, 2*x))*beta(x, x)
77
+
78
+ We can numerically evaluate the Beta function to
79
+ arbitrary precision for any complex numbers x and y:
80
+
81
+ >>> from sympy import beta
82
+ >>> beta(pi).evalf(40)
83
+ 0.02671848900111377452242355235388489324562
84
+
85
+ >>> beta(1 + I).evalf(20)
86
+ -0.2112723729365330143 - 0.7655283165378005676*I
87
+
88
+ See Also
89
+ ========
90
+
91
+ gamma: Gamma function.
92
+ uppergamma: Upper incomplete gamma function.
93
+ lowergamma: Lower incomplete gamma function.
94
+ polygamma: Polygamma function.
95
+ loggamma: Log Gamma function.
96
+ digamma: Digamma function.
97
+ trigamma: Trigamma function.
98
+
99
+ References
100
+ ==========
101
+
102
+ .. [1] https://en.wikipedia.org/wiki/Beta_function
103
+ .. [2] https://mathworld.wolfram.com/BetaFunction.html
104
+ .. [3] https://dlmf.nist.gov/5.12
105
+
106
+ """
107
+ unbranched = True
108
+
109
+ def fdiff(self, argindex):
110
+ x, y = self.args
111
+ if argindex == 1:
112
+ # Diff wrt x
113
+ return beta(x, y)*(digamma(x) - digamma(x + y))
114
+ elif argindex == 2:
115
+ # Diff wrt y
116
+ return beta(x, y)*(digamma(y) - digamma(x + y))
117
+ else:
118
+ raise ArgumentIndexError(self, argindex)
119
+
120
+ @classmethod
121
+ def eval(cls, x, y=None):
122
+ if y is None:
123
+ return beta(x, x)
124
+ if x.is_Number and y.is_Number:
125
+ return beta(x, y, evaluate=False).doit()
126
+
127
+ def doit(self, **hints):
128
+ x = xold = self.args[0]
129
+ # Deal with unevaluated single argument beta
130
+ single_argument = len(self.args) == 1
131
+ y = yold = self.args[0] if single_argument else self.args[1]
132
+ if hints.get('deep', True):
133
+ x = x.doit(**hints)
134
+ y = y.doit(**hints)
135
+ if y.is_zero or x.is_zero:
136
+ return S.ComplexInfinity
137
+ if y is S.One:
138
+ return 1/x
139
+ if x is S.One:
140
+ return 1/y
141
+ if y == x + 1:
142
+ return 1/(x*y*catalan(x))
143
+ s = x + y
144
+ if (s.is_integer and s.is_negative and x.is_integer is False and
145
+ y.is_integer is False):
146
+ return S.Zero
147
+ if x == xold and y == yold and not single_argument:
148
+ return self
149
+ return beta(x, y)
150
+
151
+ def _eval_expand_func(self, **hints):
152
+ x, y = self.args
153
+ return gamma(x)*gamma(y) / gamma(x + y)
154
+
155
+ def _eval_is_real(self):
156
+ return self.args[0].is_real and self.args[1].is_real
157
+
158
+ def _eval_conjugate(self):
159
+ return self.func(self.args[0].conjugate(), self.args[1].conjugate())
160
+
161
+ def _eval_rewrite_as_gamma(self, x, y, piecewise=True, **kwargs):
162
+ return self._eval_expand_func(**kwargs)
163
+
164
+ def _eval_rewrite_as_Integral(self, x, y, **kwargs):
165
+ from sympy.integrals.integrals import Integral
166
+ t = Dummy('t')
167
+ return Integral(t**(x - 1)*(1 - t)**(y - 1), (t, 0, 1))
168
+
169
+ ###############################################################################
170
+ ########################## INCOMPLETE BETA FUNCTION ###########################
171
+ ###############################################################################
172
+
173
+ class betainc(Function):
174
+ r"""
175
+ The Generalized Incomplete Beta function is defined as
176
+
177
+ .. math::
178
+ \mathrm{B}_{(x_1, x_2)}(a, b) = \int_{x_1}^{x_2} t^{a - 1} (1 - t)^{b - 1} dt
179
+
180
+ The Incomplete Beta function is a special case
181
+ of the Generalized Incomplete Beta function :
182
+
183
+ .. math:: \mathrm{B}_z (a, b) = \mathrm{B}_{(0, z)}(a, b)
184
+
185
+ The Incomplete Beta function satisfies :
186
+
187
+ .. math:: \mathrm{B}_z (a, b) = (-1)^a \mathrm{B}_{\frac{z}{z - 1}} (a, 1 - a - b)
188
+
189
+ The Beta function is a special case of the Incomplete Beta function :
190
+
191
+ .. math:: \mathrm{B}(a, b) = \mathrm{B}_{1}(a, b)
192
+
193
+ Examples
194
+ ========
195
+
196
+ >>> from sympy import betainc, symbols, conjugate
197
+ >>> a, b, x, x1, x2 = symbols('a b x x1 x2')
198
+
199
+ The Generalized Incomplete Beta function is given by:
200
+
201
+ >>> betainc(a, b, x1, x2)
202
+ betainc(a, b, x1, x2)
203
+
204
+ The Incomplete Beta function can be obtained as follows:
205
+
206
+ >>> betainc(a, b, 0, x)
207
+ betainc(a, b, 0, x)
208
+
209
+ The Incomplete Beta function obeys the mirror symmetry:
210
+
211
+ >>> conjugate(betainc(a, b, x1, x2))
212
+ betainc(conjugate(a), conjugate(b), conjugate(x1), conjugate(x2))
213
+
214
+ We can numerically evaluate the Incomplete Beta function to
215
+ arbitrary precision for any complex numbers a, b, x1 and x2:
216
+
217
+ >>> from sympy import betainc, I
218
+ >>> betainc(2, 3, 4, 5).evalf(10)
219
+ 56.08333333
220
+ >>> betainc(0.75, 1 - 4*I, 0, 2 + 3*I).evalf(25)
221
+ 0.2241657956955709603655887 + 0.3619619242700451992411724*I
222
+
223
+ The Generalized Incomplete Beta function can be expressed
224
+ in terms of the Generalized Hypergeometric function.
225
+
226
+ >>> from sympy import hyper
227
+ >>> betainc(a, b, x1, x2).rewrite(hyper)
228
+ (-x1**a*hyper((a, 1 - b), (a + 1,), x1) + x2**a*hyper((a, 1 - b), (a + 1,), x2))/a
229
+
230
+ See Also
231
+ ========
232
+
233
+ beta: Beta function
234
+ hyper: Generalized Hypergeometric function
235
+
236
+ References
237
+ ==========
238
+
239
+ .. [1] https://en.wikipedia.org/wiki/Beta_function#Incomplete_beta_function
240
+ .. [2] https://dlmf.nist.gov/8.17
241
+ .. [3] https://functions.wolfram.com/GammaBetaErf/Beta4/
242
+ .. [4] https://functions.wolfram.com/GammaBetaErf/BetaRegularized4/02/
243
+
244
+ """
245
+ nargs = 4
246
+ unbranched = True
247
+
248
+ def fdiff(self, argindex):
249
+ a, b, x1, x2 = self.args
250
+ if argindex == 3:
251
+ # Diff wrt x1
252
+ return -(1 - x1)**(b - 1)*x1**(a - 1)
253
+ elif argindex == 4:
254
+ # Diff wrt x2
255
+ return (1 - x2)**(b - 1)*x2**(a - 1)
256
+ else:
257
+ raise ArgumentIndexError(self, argindex)
258
+
259
+ def _eval_mpmath(self):
260
+ return betainc_mpmath_fix, self.args
261
+
262
+ def _eval_is_real(self):
263
+ if all(arg.is_real for arg in self.args):
264
+ return True
265
+
266
+ def _eval_conjugate(self):
267
+ return self.func(*map(conjugate, self.args))
268
+
269
+ def _eval_rewrite_as_Integral(self, a, b, x1, x2, **kwargs):
270
+ from sympy.integrals.integrals import Integral
271
+ t = Dummy('t')
272
+ return Integral(t**(a - 1)*(1 - t)**(b - 1), (t, x1, x2))
273
+
274
+ def _eval_rewrite_as_hyper(self, a, b, x1, x2, **kwargs):
275
+ from sympy.functions.special.hyper import hyper
276
+ return (x2**a * hyper((a, 1 - b), (a + 1,), x2) - x1**a * hyper((a, 1 - b), (a + 1,), x1)) / a
277
+
278
+ ###############################################################################
279
+ #################### REGULARIZED INCOMPLETE BETA FUNCTION #####################
280
+ ###############################################################################
281
+
282
+ class betainc_regularized(Function):
283
+ r"""
284
+ The Generalized Regularized Incomplete Beta function is given by
285
+
286
+ .. math::
287
+ \mathrm{I}_{(x_1, x_2)}(a, b) = \frac{\mathrm{B}_{(x_1, x_2)}(a, b)}{\mathrm{B}(a, b)}
288
+
289
+ The Regularized Incomplete Beta function is a special case
290
+ of the Generalized Regularized Incomplete Beta function :
291
+
292
+ .. math:: \mathrm{I}_z (a, b) = \mathrm{I}_{(0, z)}(a, b)
293
+
294
+ The Regularized Incomplete Beta function is the cumulative distribution
295
+ function of the beta distribution.
296
+
297
+ Examples
298
+ ========
299
+
300
+ >>> from sympy import betainc_regularized, symbols, conjugate
301
+ >>> a, b, x, x1, x2 = symbols('a b x x1 x2')
302
+
303
+ The Generalized Regularized Incomplete Beta
304
+ function is given by:
305
+
306
+ >>> betainc_regularized(a, b, x1, x2)
307
+ betainc_regularized(a, b, x1, x2)
308
+
309
+ The Regularized Incomplete Beta function
310
+ can be obtained as follows:
311
+
312
+ >>> betainc_regularized(a, b, 0, x)
313
+ betainc_regularized(a, b, 0, x)
314
+
315
+ The Regularized Incomplete Beta function
316
+ obeys the mirror symmetry:
317
+
318
+ >>> conjugate(betainc_regularized(a, b, x1, x2))
319
+ betainc_regularized(conjugate(a), conjugate(b), conjugate(x1), conjugate(x2))
320
+
321
+ We can numerically evaluate the Regularized Incomplete Beta function
322
+ to arbitrary precision for any complex numbers a, b, x1 and x2:
323
+
324
+ >>> from sympy import betainc_regularized, pi, E
325
+ >>> betainc_regularized(1, 2, 0, 0.25).evalf(10)
326
+ 0.4375000000
327
+ >>> betainc_regularized(pi, E, 0, 1).evalf(5)
328
+ 1.00000
329
+
330
+ The Generalized Regularized Incomplete Beta function can be
331
+ expressed in terms of the Generalized Hypergeometric function.
332
+
333
+ >>> from sympy import hyper
334
+ >>> betainc_regularized(a, b, x1, x2).rewrite(hyper)
335
+ (-x1**a*hyper((a, 1 - b), (a + 1,), x1) + x2**a*hyper((a, 1 - b), (a + 1,), x2))/(a*beta(a, b))
336
+
337
+ See Also
338
+ ========
339
+
340
+ beta: Beta function
341
+ hyper: Generalized Hypergeometric function
342
+
343
+ References
344
+ ==========
345
+
346
+ .. [1] https://en.wikipedia.org/wiki/Beta_function#Incomplete_beta_function
347
+ .. [2] https://dlmf.nist.gov/8.17
348
+ .. [3] https://functions.wolfram.com/GammaBetaErf/Beta4/
349
+ .. [4] https://functions.wolfram.com/GammaBetaErf/BetaRegularized4/02/
350
+
351
+ """
352
+ nargs = 4
353
+ unbranched = True
354
+
355
+ def __new__(cls, a, b, x1, x2):
356
+ return Function.__new__(cls, a, b, x1, x2)
357
+
358
+ def _eval_mpmath(self):
359
+ return betainc_mpmath_fix, (*self.args, S(1))
360
+
361
+ def fdiff(self, argindex):
362
+ a, b, x1, x2 = self.args
363
+ if argindex == 3:
364
+ # Diff wrt x1
365
+ return -(1 - x1)**(b - 1)*x1**(a - 1) / beta(a, b)
366
+ elif argindex == 4:
367
+ # Diff wrt x2
368
+ return (1 - x2)**(b - 1)*x2**(a - 1) / beta(a, b)
369
+ else:
370
+ raise ArgumentIndexError(self, argindex)
371
+
372
+ def _eval_is_real(self):
373
+ if all(arg.is_real for arg in self.args):
374
+ return True
375
+
376
+ def _eval_conjugate(self):
377
+ return self.func(*map(conjugate, self.args))
378
+
379
+ def _eval_rewrite_as_Integral(self, a, b, x1, x2, **kwargs):
380
+ from sympy.integrals.integrals import Integral
381
+ t = Dummy('t')
382
+ integrand = t**(a - 1)*(1 - t)**(b - 1)
383
+ expr = Integral(integrand, (t, x1, x2))
384
+ return expr / Integral(integrand, (t, 0, 1))
385
+
386
+ def _eval_rewrite_as_hyper(self, a, b, x1, x2, **kwargs):
387
+ from sympy.functions.special.hyper import hyper
388
+ expr = (x2**a * hyper((a, 1 - b), (a + 1,), x2) - x1**a * hyper((a, 1 - b), (a + 1,), x1)) / a
389
+ return expr / beta(a, b)
env-llmeval/lib/python3.10/site-packages/sympy/functions/special/bsplines.py ADDED
@@ -0,0 +1,351 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ from sympy.core import S, sympify
2
+ from sympy.core.symbol import (Dummy, symbols)
3
+ from sympy.functions import Piecewise, piecewise_fold
4
+ from sympy.logic.boolalg import And
5
+ from sympy.sets.sets import Interval
6
+
7
+ from functools import lru_cache
8
+
9
+
10
+ def _ivl(cond, x):
11
+ """return the interval corresponding to the condition
12
+
13
+ Conditions in spline's Piecewise give the range over
14
+ which an expression is valid like (lo <= x) & (x <= hi).
15
+ This function returns (lo, hi).
16
+ """
17
+ if isinstance(cond, And) and len(cond.args) == 2:
18
+ a, b = cond.args
19
+ if a.lts == x:
20
+ a, b = b, a
21
+ return a.lts, b.gts
22
+ raise TypeError('unexpected cond type: %s' % cond)
23
+
24
+
25
+ def _add_splines(c, b1, d, b2, x):
26
+ """Construct c*b1 + d*b2."""
27
+
28
+ if S.Zero in (b1, c):
29
+ rv = piecewise_fold(d * b2)
30
+ elif S.Zero in (b2, d):
31
+ rv = piecewise_fold(c * b1)
32
+ else:
33
+ new_args = []
34
+ # Just combining the Piecewise without any fancy optimization
35
+ p1 = piecewise_fold(c * b1)
36
+ p2 = piecewise_fold(d * b2)
37
+
38
+ # Search all Piecewise arguments except (0, True)
39
+ p2args = list(p2.args[:-1])
40
+
41
+ # This merging algorithm assumes the conditions in
42
+ # p1 and p2 are sorted
43
+ for arg in p1.args[:-1]:
44
+ expr = arg.expr
45
+ cond = arg.cond
46
+
47
+ lower = _ivl(cond, x)[0]
48
+
49
+ # Check p2 for matching conditions that can be merged
50
+ for i, arg2 in enumerate(p2args):
51
+ expr2 = arg2.expr
52
+ cond2 = arg2.cond
53
+
54
+ lower_2, upper_2 = _ivl(cond2, x)
55
+ if cond2 == cond:
56
+ # Conditions match, join expressions
57
+ expr += expr2
58
+ # Remove matching element
59
+ del p2args[i]
60
+ # No need to check the rest
61
+ break
62
+ elif lower_2 < lower and upper_2 <= lower:
63
+ # Check if arg2 condition smaller than arg1,
64
+ # add to new_args by itself (no match expected
65
+ # in p1)
66
+ new_args.append(arg2)
67
+ del p2args[i]
68
+ break
69
+
70
+ # Checked all, add expr and cond
71
+ new_args.append((expr, cond))
72
+
73
+ # Add remaining items from p2args
74
+ new_args.extend(p2args)
75
+
76
+ # Add final (0, True)
77
+ new_args.append((0, True))
78
+
79
+ rv = Piecewise(*new_args, evaluate=False)
80
+
81
+ return rv.expand()
82
+
83
+
84
+ @lru_cache(maxsize=128)
85
+ def bspline_basis(d, knots, n, x):
86
+ """
87
+ The $n$-th B-spline at $x$ of degree $d$ with knots.
88
+
89
+ Explanation
90
+ ===========
91
+
92
+ B-Splines are piecewise polynomials of degree $d$. They are defined on a
93
+ set of knots, which is a sequence of integers or floats.
94
+
95
+ Examples
96
+ ========
97
+
98
+ The 0th degree splines have a value of 1 on a single interval:
99
+
100
+ >>> from sympy import bspline_basis
101
+ >>> from sympy.abc import x
102
+ >>> d = 0
103
+ >>> knots = tuple(range(5))
104
+ >>> bspline_basis(d, knots, 0, x)
105
+ Piecewise((1, (x >= 0) & (x <= 1)), (0, True))
106
+
107
+ For a given ``(d, knots)`` there are ``len(knots)-d-1`` B-splines
108
+ defined, that are indexed by ``n`` (starting at 0).
109
+
110
+ Here is an example of a cubic B-spline:
111
+
112
+ >>> bspline_basis(3, tuple(range(5)), 0, x)
113
+ Piecewise((x**3/6, (x >= 0) & (x <= 1)),
114
+ (-x**3/2 + 2*x**2 - 2*x + 2/3,
115
+ (x >= 1) & (x <= 2)),
116
+ (x**3/2 - 4*x**2 + 10*x - 22/3,
117
+ (x >= 2) & (x <= 3)),
118
+ (-x**3/6 + 2*x**2 - 8*x + 32/3,
119
+ (x >= 3) & (x <= 4)),
120
+ (0, True))
121
+
122
+ By repeating knot points, you can introduce discontinuities in the
123
+ B-splines and their derivatives:
124
+
125
+ >>> d = 1
126
+ >>> knots = (0, 0, 2, 3, 4)
127
+ >>> bspline_basis(d, knots, 0, x)
128
+ Piecewise((1 - x/2, (x >= 0) & (x <= 2)), (0, True))
129
+
130
+ It is quite time consuming to construct and evaluate B-splines. If
131
+ you need to evaluate a B-spline many times, it is best to lambdify them
132
+ first:
133
+
134
+ >>> from sympy import lambdify
135
+ >>> d = 3
136
+ >>> knots = tuple(range(10))
137
+ >>> b0 = bspline_basis(d, knots, 0, x)
138
+ >>> f = lambdify(x, b0)
139
+ >>> y = f(0.5)
140
+
141
+ Parameters
142
+ ==========
143
+
144
+ d : integer
145
+ degree of bspline
146
+
147
+ knots : list of integer values
148
+ list of knots points of bspline
149
+
150
+ n : integer
151
+ $n$-th B-spline
152
+
153
+ x : symbol
154
+
155
+ See Also
156
+ ========
157
+
158
+ bspline_basis_set
159
+
160
+ References
161
+ ==========
162
+
163
+ .. [1] https://en.wikipedia.org/wiki/B-spline
164
+
165
+ """
166
+ # make sure x has no assumptions so conditions don't evaluate
167
+ xvar = x
168
+ x = Dummy()
169
+
170
+ knots = tuple(sympify(k) for k in knots)
171
+ d = int(d)
172
+ n = int(n)
173
+ n_knots = len(knots)
174
+ n_intervals = n_knots - 1
175
+ if n + d + 1 > n_intervals:
176
+ raise ValueError("n + d + 1 must not exceed len(knots) - 1")
177
+ if d == 0:
178
+ result = Piecewise(
179
+ (S.One, Interval(knots[n], knots[n + 1]).contains(x)), (0, True)
180
+ )
181
+ elif d > 0:
182
+ denom = knots[n + d + 1] - knots[n + 1]
183
+ if denom != S.Zero:
184
+ B = (knots[n + d + 1] - x) / denom
185
+ b2 = bspline_basis(d - 1, knots, n + 1, x)
186
+ else:
187
+ b2 = B = S.Zero
188
+
189
+ denom = knots[n + d] - knots[n]
190
+ if denom != S.Zero:
191
+ A = (x - knots[n]) / denom
192
+ b1 = bspline_basis(d - 1, knots, n, x)
193
+ else:
194
+ b1 = A = S.Zero
195
+
196
+ result = _add_splines(A, b1, B, b2, x)
197
+ else:
198
+ raise ValueError("degree must be non-negative: %r" % n)
199
+
200
+ # return result with user-given x
201
+ return result.xreplace({x: xvar})
202
+
203
+
204
+ def bspline_basis_set(d, knots, x):
205
+ """
206
+ Return the ``len(knots)-d-1`` B-splines at *x* of degree *d*
207
+ with *knots*.
208
+
209
+ Explanation
210
+ ===========
211
+
212
+ This function returns a list of piecewise polynomials that are the
213
+ ``len(knots)-d-1`` B-splines of degree *d* for the given knots.
214
+ This function calls ``bspline_basis(d, knots, n, x)`` for different
215
+ values of *n*.
216
+
217
+ Examples
218
+ ========
219
+
220
+ >>> from sympy import bspline_basis_set
221
+ >>> from sympy.abc import x
222
+ >>> d = 2
223
+ >>> knots = range(5)
224
+ >>> splines = bspline_basis_set(d, knots, x)
225
+ >>> splines
226
+ [Piecewise((x**2/2, (x >= 0) & (x <= 1)),
227
+ (-x**2 + 3*x - 3/2, (x >= 1) & (x <= 2)),
228
+ (x**2/2 - 3*x + 9/2, (x >= 2) & (x <= 3)),
229
+ (0, True)),
230
+ Piecewise((x**2/2 - x + 1/2, (x >= 1) & (x <= 2)),
231
+ (-x**2 + 5*x - 11/2, (x >= 2) & (x <= 3)),
232
+ (x**2/2 - 4*x + 8, (x >= 3) & (x <= 4)),
233
+ (0, True))]
234
+
235
+ Parameters
236
+ ==========
237
+
238
+ d : integer
239
+ degree of bspline
240
+
241
+ knots : list of integers
242
+ list of knots points of bspline
243
+
244
+ x : symbol
245
+
246
+ See Also
247
+ ========
248
+
249
+ bspline_basis
250
+
251
+ """
252
+ n_splines = len(knots) - d - 1
253
+ return [bspline_basis(d, tuple(knots), i, x) for i in range(n_splines)]
254
+
255
+
256
+ def interpolating_spline(d, x, X, Y):
257
+ """
258
+ Return spline of degree *d*, passing through the given *X*
259
+ and *Y* values.
260
+
261
+ Explanation
262
+ ===========
263
+
264
+ This function returns a piecewise function such that each part is
265
+ a polynomial of degree not greater than *d*. The value of *d*
266
+ must be 1 or greater and the values of *X* must be strictly
267
+ increasing.
268
+
269
+ Examples
270
+ ========
271
+
272
+ >>> from sympy import interpolating_spline
273
+ >>> from sympy.abc import x
274
+ >>> interpolating_spline(1, x, [1, 2, 4, 7], [3, 6, 5, 7])
275
+ Piecewise((3*x, (x >= 1) & (x <= 2)),
276
+ (7 - x/2, (x >= 2) & (x <= 4)),
277
+ (2*x/3 + 7/3, (x >= 4) & (x <= 7)))
278
+ >>> interpolating_spline(3, x, [-2, 0, 1, 3, 4], [4, 2, 1, 1, 3])
279
+ Piecewise((7*x**3/117 + 7*x**2/117 - 131*x/117 + 2, (x >= -2) & (x <= 1)),
280
+ (10*x**3/117 - 2*x**2/117 - 122*x/117 + 77/39, (x >= 1) & (x <= 4)))
281
+
282
+ Parameters
283
+ ==========
284
+
285
+ d : integer
286
+ Degree of Bspline strictly greater than equal to one
287
+
288
+ x : symbol
289
+
290
+ X : list of strictly increasing real values
291
+ list of X coordinates through which the spline passes
292
+
293
+ Y : list of real values
294
+ list of corresponding Y coordinates through which the spline passes
295
+
296
+ See Also
297
+ ========
298
+
299
+ bspline_basis_set, interpolating_poly
300
+
301
+ """
302
+ from sympy.solvers.solveset import linsolve
303
+ from sympy.matrices.dense import Matrix
304
+
305
+ # Input sanitization
306
+ d = sympify(d)
307
+ if not (d.is_Integer and d.is_positive):
308
+ raise ValueError("Spline degree must be a positive integer, not %s." % d)
309
+ if len(X) != len(Y):
310
+ raise ValueError("Number of X and Y coordinates must be the same.")
311
+ if len(X) < d + 1:
312
+ raise ValueError("Degree must be less than the number of control points.")
313
+ if not all(a < b for a, b in zip(X, X[1:])):
314
+ raise ValueError("The x-coordinates must be strictly increasing.")
315
+ X = [sympify(i) for i in X]
316
+
317
+ # Evaluating knots value
318
+ if d.is_odd:
319
+ j = (d + 1) // 2
320
+ interior_knots = X[j:-j]
321
+ else:
322
+ j = d // 2
323
+ interior_knots = [
324
+ (a + b)/2 for a, b in zip(X[j : -j - 1], X[j + 1 : -j])
325
+ ]
326
+
327
+ knots = [X[0]] * (d + 1) + list(interior_knots) + [X[-1]] * (d + 1)
328
+
329
+ basis = bspline_basis_set(d, knots, x)
330
+
331
+ A = [[b.subs(x, v) for b in basis] for v in X]
332
+
333
+ coeff = linsolve((Matrix(A), Matrix(Y)), symbols("c0:{}".format(len(X)), cls=Dummy))
334
+ coeff = list(coeff)[0]
335
+ intervals = {c for b in basis for (e, c) in b.args if c != True}
336
+
337
+ # Sorting the intervals
338
+ # ival contains the end-points of each interval
339
+ ival = [_ivl(c, x) for c in intervals]
340
+ com = zip(ival, intervals)
341
+ com = sorted(com, key=lambda x: x[0])
342
+ intervals = [y for x, y in com]
343
+
344
+ basis_dicts = [{c: e for (e, c) in b.args} for b in basis]
345
+ spline = []
346
+ for i in intervals:
347
+ piece = sum(
348
+ [c * d.get(i, S.Zero) for (c, d) in zip(coeff, basis_dicts)], S.Zero
349
+ )
350
+ spline.append((piece, i))
351
+ return Piecewise(*spline)
env-llmeval/lib/python3.10/site-packages/sympy/functions/special/delta_functions.py ADDED
@@ -0,0 +1,664 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ from sympy.core import S, diff
2
+ from sympy.core.function import Function, ArgumentIndexError
3
+ from sympy.core.logic import fuzzy_not
4
+ from sympy.core.relational import Eq, Ne
5
+ from sympy.functions.elementary.complexes import im, sign
6
+ from sympy.functions.elementary.piecewise import Piecewise
7
+ from sympy.polys.polyerrors import PolynomialError
8
+ from sympy.polys.polyroots import roots
9
+ from sympy.utilities.misc import filldedent
10
+
11
+
12
+ ###############################################################################
13
+ ################################ DELTA FUNCTION ###############################
14
+ ###############################################################################
15
+
16
+
17
+ class DiracDelta(Function):
18
+ r"""
19
+ The DiracDelta function and its derivatives.
20
+
21
+ Explanation
22
+ ===========
23
+
24
+ DiracDelta is not an ordinary function. It can be rigorously defined either
25
+ as a distribution or as a measure.
26
+
27
+ DiracDelta only makes sense in definite integrals, and in particular,
28
+ integrals of the form ``Integral(f(x)*DiracDelta(x - x0), (x, a, b))``,
29
+ where it equals ``f(x0)`` if ``a <= x0 <= b`` and ``0`` otherwise. Formally,
30
+ DiracDelta acts in some ways like a function that is ``0`` everywhere except
31
+ at ``0``, but in many ways it also does not. It can often be useful to treat
32
+ DiracDelta in formal ways, building up and manipulating expressions with
33
+ delta functions (which may eventually be integrated), but care must be taken
34
+ to not treat it as a real function. SymPy's ``oo`` is similar. It only
35
+ truly makes sense formally in certain contexts (such as integration limits),
36
+ but SymPy allows its use everywhere, and it tries to be consistent with
37
+ operations on it (like ``1/oo``), but it is easy to get into trouble and get
38
+ wrong results if ``oo`` is treated too much like a number. Similarly, if
39
+ DiracDelta is treated too much like a function, it is easy to get wrong or
40
+ nonsensical results.
41
+
42
+ DiracDelta function has the following properties:
43
+
44
+ 1) $\frac{d}{d x} \theta(x) = \delta(x)$
45
+ 2) $\int_{-\infty}^\infty \delta(x - a)f(x)\, dx = f(a)$ and $\int_{a-
46
+ \epsilon}^{a+\epsilon} \delta(x - a)f(x)\, dx = f(a)$
47
+ 3) $\delta(x) = 0$ for all $x \neq 0$
48
+ 4) $\delta(g(x)) = \sum_i \frac{\delta(x - x_i)}{\|g'(x_i)\|}$ where $x_i$
49
+ are the roots of $g$
50
+ 5) $\delta(-x) = \delta(x)$
51
+
52
+ Derivatives of ``k``-th order of DiracDelta have the following properties:
53
+
54
+ 6) $\delta(x, k) = 0$ for all $x \neq 0$
55
+ 7) $\delta(-x, k) = -\delta(x, k)$ for odd $k$
56
+ 8) $\delta(-x, k) = \delta(x, k)$ for even $k$
57
+
58
+ Examples
59
+ ========
60
+
61
+ >>> from sympy import DiracDelta, diff, pi
62
+ >>> from sympy.abc import x, y
63
+
64
+ >>> DiracDelta(x)
65
+ DiracDelta(x)
66
+ >>> DiracDelta(1)
67
+ 0
68
+ >>> DiracDelta(-1)
69
+ 0
70
+ >>> DiracDelta(pi)
71
+ 0
72
+ >>> DiracDelta(x - 4).subs(x, 4)
73
+ DiracDelta(0)
74
+ >>> diff(DiracDelta(x))
75
+ DiracDelta(x, 1)
76
+ >>> diff(DiracDelta(x - 1), x, 2)
77
+ DiracDelta(x - 1, 2)
78
+ >>> diff(DiracDelta(x**2 - 1), x, 2)
79
+ 2*(2*x**2*DiracDelta(x**2 - 1, 2) + DiracDelta(x**2 - 1, 1))
80
+ >>> DiracDelta(3*x).is_simple(x)
81
+ True
82
+ >>> DiracDelta(x**2).is_simple(x)
83
+ False
84
+ >>> DiracDelta((x**2 - 1)*y).expand(diracdelta=True, wrt=x)
85
+ DiracDelta(x - 1)/(2*Abs(y)) + DiracDelta(x + 1)/(2*Abs(y))
86
+
87
+ See Also
88
+ ========
89
+
90
+ Heaviside
91
+ sympy.simplify.simplify.simplify, is_simple
92
+ sympy.functions.special.tensor_functions.KroneckerDelta
93
+
94
+ References
95
+ ==========
96
+
97
+ .. [1] https://mathworld.wolfram.com/DeltaFunction.html
98
+
99
+ """
100
+
101
+ is_real = True
102
+
103
+ def fdiff(self, argindex=1):
104
+ """
105
+ Returns the first derivative of a DiracDelta Function.
106
+
107
+ Explanation
108
+ ===========
109
+
110
+ The difference between ``diff()`` and ``fdiff()`` is: ``diff()`` is the
111
+ user-level function and ``fdiff()`` is an object method. ``fdiff()`` is
112
+ a convenience method available in the ``Function`` class. It returns
113
+ the derivative of the function without considering the chain rule.
114
+ ``diff(function, x)`` calls ``Function._eval_derivative`` which in turn
115
+ calls ``fdiff()`` internally to compute the derivative of the function.
116
+
117
+ Examples
118
+ ========
119
+
120
+ >>> from sympy import DiracDelta, diff
121
+ >>> from sympy.abc import x
122
+
123
+ >>> DiracDelta(x).fdiff()
124
+ DiracDelta(x, 1)
125
+
126
+ >>> DiracDelta(x, 1).fdiff()
127
+ DiracDelta(x, 2)
128
+
129
+ >>> DiracDelta(x**2 - 1).fdiff()
130
+ DiracDelta(x**2 - 1, 1)
131
+
132
+ >>> diff(DiracDelta(x, 1)).fdiff()
133
+ DiracDelta(x, 3)
134
+
135
+ Parameters
136
+ ==========
137
+
138
+ argindex : integer
139
+ degree of derivative
140
+
141
+ """
142
+ if argindex == 1:
143
+ #I didn't know if there is a better way to handle default arguments
144
+ k = 0
145
+ if len(self.args) > 1:
146
+ k = self.args[1]
147
+ return self.func(self.args[0], k + 1)
148
+ else:
149
+ raise ArgumentIndexError(self, argindex)
150
+
151
+ @classmethod
152
+ def eval(cls, arg, k=S.Zero):
153
+ """
154
+ Returns a simplified form or a value of DiracDelta depending on the
155
+ argument passed by the DiracDelta object.
156
+
157
+ Explanation
158
+ ===========
159
+
160
+ The ``eval()`` method is automatically called when the ``DiracDelta``
161
+ class is about to be instantiated and it returns either some simplified
162
+ instance or the unevaluated instance depending on the argument passed.
163
+ In other words, ``eval()`` method is not needed to be called explicitly,
164
+ it is being called and evaluated once the object is called.
165
+
166
+ Examples
167
+ ========
168
+
169
+ >>> from sympy import DiracDelta, S
170
+ >>> from sympy.abc import x
171
+
172
+ >>> DiracDelta(x)
173
+ DiracDelta(x)
174
+
175
+ >>> DiracDelta(-x, 1)
176
+ -DiracDelta(x, 1)
177
+
178
+ >>> DiracDelta(1)
179
+ 0
180
+
181
+ >>> DiracDelta(5, 1)
182
+ 0
183
+
184
+ >>> DiracDelta(0)
185
+ DiracDelta(0)
186
+
187
+ >>> DiracDelta(-1)
188
+ 0
189
+
190
+ >>> DiracDelta(S.NaN)
191
+ nan
192
+
193
+ >>> DiracDelta(x - 100).subs(x, 5)
194
+ 0
195
+
196
+ >>> DiracDelta(x - 100).subs(x, 100)
197
+ DiracDelta(0)
198
+
199
+ Parameters
200
+ ==========
201
+
202
+ k : integer
203
+ order of derivative
204
+
205
+ arg : argument passed to DiracDelta
206
+
207
+ """
208
+ if not k.is_Integer or k.is_negative:
209
+ raise ValueError("Error: the second argument of DiracDelta must be \
210
+ a non-negative integer, %s given instead." % (k,))
211
+ if arg is S.NaN:
212
+ return S.NaN
213
+ if arg.is_nonzero:
214
+ return S.Zero
215
+ if fuzzy_not(im(arg).is_zero):
216
+ raise ValueError(filldedent('''
217
+ Function defined only for Real Values.
218
+ Complex part: %s found in %s .''' % (
219
+ repr(im(arg)), repr(arg))))
220
+ c, nc = arg.args_cnc()
221
+ if c and c[0] is S.NegativeOne:
222
+ # keep this fast and simple instead of using
223
+ # could_extract_minus_sign
224
+ if k.is_odd:
225
+ return -cls(-arg, k)
226
+ elif k.is_even:
227
+ return cls(-arg, k) if k else cls(-arg)
228
+ elif k.is_zero:
229
+ return cls(arg, evaluate=False)
230
+
231
+ def _eval_expand_diracdelta(self, **hints):
232
+ """
233
+ Compute a simplified representation of the function using
234
+ property number 4. Pass ``wrt`` as a hint to expand the expression
235
+ with respect to a particular variable.
236
+
237
+ Explanation
238
+ ===========
239
+
240
+ ``wrt`` is:
241
+
242
+ - a variable with respect to which a DiracDelta expression will
243
+ get expanded.
244
+
245
+ Examples
246
+ ========
247
+
248
+ >>> from sympy import DiracDelta
249
+ >>> from sympy.abc import x, y
250
+
251
+ >>> DiracDelta(x*y).expand(diracdelta=True, wrt=x)
252
+ DiracDelta(x)/Abs(y)
253
+ >>> DiracDelta(x*y).expand(diracdelta=True, wrt=y)
254
+ DiracDelta(y)/Abs(x)
255
+
256
+ >>> DiracDelta(x**2 + x - 2).expand(diracdelta=True, wrt=x)
257
+ DiracDelta(x - 1)/3 + DiracDelta(x + 2)/3
258
+
259
+ See Also
260
+ ========
261
+
262
+ is_simple, Diracdelta
263
+
264
+ """
265
+ wrt = hints.get('wrt', None)
266
+ if wrt is None:
267
+ free = self.free_symbols
268
+ if len(free) == 1:
269
+ wrt = free.pop()
270
+ else:
271
+ raise TypeError(filldedent('''
272
+ When there is more than 1 free symbol or variable in the expression,
273
+ the 'wrt' keyword is required as a hint to expand when using the
274
+ DiracDelta hint.'''))
275
+
276
+ if not self.args[0].has(wrt) or (len(self.args) > 1 and self.args[1] != 0 ):
277
+ return self
278
+ try:
279
+ argroots = roots(self.args[0], wrt)
280
+ result = 0
281
+ valid = True
282
+ darg = abs(diff(self.args[0], wrt))
283
+ for r, m in argroots.items():
284
+ if r.is_real is not False and m == 1:
285
+ result += self.func(wrt - r)/darg.subs(wrt, r)
286
+ else:
287
+ # don't handle non-real and if m != 1 then
288
+ # a polynomial will have a zero in the derivative (darg)
289
+ # at r
290
+ valid = False
291
+ break
292
+ if valid:
293
+ return result
294
+ except PolynomialError:
295
+ pass
296
+ return self
297
+
298
+ def is_simple(self, x):
299
+ """
300
+ Tells whether the argument(args[0]) of DiracDelta is a linear
301
+ expression in *x*.
302
+
303
+ Examples
304
+ ========
305
+
306
+ >>> from sympy import DiracDelta, cos
307
+ >>> from sympy.abc import x, y
308
+
309
+ >>> DiracDelta(x*y).is_simple(x)
310
+ True
311
+ >>> DiracDelta(x*y).is_simple(y)
312
+ True
313
+
314
+ >>> DiracDelta(x**2 + x - 2).is_simple(x)
315
+ False
316
+
317
+ >>> DiracDelta(cos(x)).is_simple(x)
318
+ False
319
+
320
+ Parameters
321
+ ==========
322
+
323
+ x : can be a symbol
324
+
325
+ See Also
326
+ ========
327
+
328
+ sympy.simplify.simplify.simplify, DiracDelta
329
+
330
+ """
331
+ p = self.args[0].as_poly(x)
332
+ if p:
333
+ return p.degree() == 1
334
+ return False
335
+
336
+ def _eval_rewrite_as_Piecewise(self, *args, **kwargs):
337
+ """
338
+ Represents DiracDelta in a piecewise form.
339
+
340
+ Examples
341
+ ========
342
+
343
+ >>> from sympy import DiracDelta, Piecewise, Symbol
344
+ >>> x = Symbol('x')
345
+
346
+ >>> DiracDelta(x).rewrite(Piecewise)
347
+ Piecewise((DiracDelta(0), Eq(x, 0)), (0, True))
348
+
349
+ >>> DiracDelta(x - 5).rewrite(Piecewise)
350
+ Piecewise((DiracDelta(0), Eq(x, 5)), (0, True))
351
+
352
+ >>> DiracDelta(x**2 - 5).rewrite(Piecewise)
353
+ Piecewise((DiracDelta(0), Eq(x**2, 5)), (0, True))
354
+
355
+ >>> DiracDelta(x - 5, 4).rewrite(Piecewise)
356
+ DiracDelta(x - 5, 4)
357
+
358
+ """
359
+ if len(args) == 1:
360
+ return Piecewise((DiracDelta(0), Eq(args[0], 0)), (0, True))
361
+
362
+ def _eval_rewrite_as_SingularityFunction(self, *args, **kwargs):
363
+ """
364
+ Returns the DiracDelta expression written in the form of Singularity
365
+ Functions.
366
+
367
+ """
368
+ from sympy.solvers import solve
369
+ from sympy.functions.special.singularity_functions import SingularityFunction
370
+ if self == DiracDelta(0):
371
+ return SingularityFunction(0, 0, -1)
372
+ if self == DiracDelta(0, 1):
373
+ return SingularityFunction(0, 0, -2)
374
+ free = self.free_symbols
375
+ if len(free) == 1:
376
+ x = (free.pop())
377
+ if len(args) == 1:
378
+ return SingularityFunction(x, solve(args[0], x)[0], -1)
379
+ return SingularityFunction(x, solve(args[0], x)[0], -args[1] - 1)
380
+ else:
381
+ # I don't know how to handle the case for DiracDelta expressions
382
+ # having arguments with more than one variable.
383
+ raise TypeError(filldedent('''
384
+ rewrite(SingularityFunction) does not support
385
+ arguments with more that one variable.'''))
386
+
387
+
388
+ ###############################################################################
389
+ ############################## HEAVISIDE FUNCTION #############################
390
+ ###############################################################################
391
+
392
+
393
+ class Heaviside(Function):
394
+ r"""
395
+ Heaviside step function.
396
+
397
+ Explanation
398
+ ===========
399
+
400
+ The Heaviside step function has the following properties:
401
+
402
+ 1) $\frac{d}{d x} \theta(x) = \delta(x)$
403
+ 2) $\theta(x) = \begin{cases} 0 & \text{for}\: x < 0 \\ \frac{1}{2} &
404
+ \text{for}\: x = 0 \\1 & \text{for}\: x > 0 \end{cases}$
405
+ 3) $\frac{d}{d x} \max(x, 0) = \theta(x)$
406
+
407
+ Heaviside(x) is printed as $\theta(x)$ with the SymPy LaTeX printer.
408
+
409
+ The value at 0 is set differently in different fields. SymPy uses 1/2,
410
+ which is a convention from electronics and signal processing, and is
411
+ consistent with solving improper integrals by Fourier transform and
412
+ convolution.
413
+
414
+ To specify a different value of Heaviside at ``x=0``, a second argument
415
+ can be given. Using ``Heaviside(x, nan)`` gives an expression that will
416
+ evaluate to nan for x=0.
417
+
418
+ .. versionchanged:: 1.9 ``Heaviside(0)`` now returns 1/2 (before: undefined)
419
+
420
+ Examples
421
+ ========
422
+
423
+ >>> from sympy import Heaviside, nan
424
+ >>> from sympy.abc import x
425
+ >>> Heaviside(9)
426
+ 1
427
+ >>> Heaviside(-9)
428
+ 0
429
+ >>> Heaviside(0)
430
+ 1/2
431
+ >>> Heaviside(0, nan)
432
+ nan
433
+ >>> (Heaviside(x) + 1).replace(Heaviside(x), Heaviside(x, 1))
434
+ Heaviside(x, 1) + 1
435
+
436
+ See Also
437
+ ========
438
+
439
+ DiracDelta
440
+
441
+ References
442
+ ==========
443
+
444
+ .. [1] https://mathworld.wolfram.com/HeavisideStepFunction.html
445
+ .. [2] https://dlmf.nist.gov/1.16#iv
446
+
447
+ """
448
+
449
+ is_real = True
450
+
451
+ def fdiff(self, argindex=1):
452
+ """
453
+ Returns the first derivative of a Heaviside Function.
454
+
455
+ Examples
456
+ ========
457
+
458
+ >>> from sympy import Heaviside, diff
459
+ >>> from sympy.abc import x
460
+
461
+ >>> Heaviside(x).fdiff()
462
+ DiracDelta(x)
463
+
464
+ >>> Heaviside(x**2 - 1).fdiff()
465
+ DiracDelta(x**2 - 1)
466
+
467
+ >>> diff(Heaviside(x)).fdiff()
468
+ DiracDelta(x, 1)
469
+
470
+ Parameters
471
+ ==========
472
+
473
+ argindex : integer
474
+ order of derivative
475
+
476
+ """
477
+ if argindex == 1:
478
+ return DiracDelta(self.args[0])
479
+ else:
480
+ raise ArgumentIndexError(self, argindex)
481
+
482
+ def __new__(cls, arg, H0=S.Half, **options):
483
+ if isinstance(H0, Heaviside) and len(H0.args) == 1:
484
+ H0 = S.Half
485
+ return super(cls, cls).__new__(cls, arg, H0, **options)
486
+
487
+ @property
488
+ def pargs(self):
489
+ """Args without default S.Half"""
490
+ args = self.args
491
+ if args[1] is S.Half:
492
+ args = args[:1]
493
+ return args
494
+
495
+ @classmethod
496
+ def eval(cls, arg, H0=S.Half):
497
+ """
498
+ Returns a simplified form or a value of Heaviside depending on the
499
+ argument passed by the Heaviside object.
500
+
501
+ Explanation
502
+ ===========
503
+
504
+ The ``eval()`` method is automatically called when the ``Heaviside``
505
+ class is about to be instantiated and it returns either some simplified
506
+ instance or the unevaluated instance depending on the argument passed.
507
+ In other words, ``eval()`` method is not needed to be called explicitly,
508
+ it is being called and evaluated once the object is called.
509
+
510
+ Examples
511
+ ========
512
+
513
+ >>> from sympy import Heaviside, S
514
+ >>> from sympy.abc import x
515
+
516
+ >>> Heaviside(x)
517
+ Heaviside(x)
518
+
519
+ >>> Heaviside(19)
520
+ 1
521
+
522
+ >>> Heaviside(0)
523
+ 1/2
524
+
525
+ >>> Heaviside(0, 1)
526
+ 1
527
+
528
+ >>> Heaviside(-5)
529
+ 0
530
+
531
+ >>> Heaviside(S.NaN)
532
+ nan
533
+
534
+ >>> Heaviside(x - 100).subs(x, 5)
535
+ 0
536
+
537
+ >>> Heaviside(x - 100).subs(x, 105)
538
+ 1
539
+
540
+ Parameters
541
+ ==========
542
+
543
+ arg : argument passed by Heaviside object
544
+
545
+ H0 : value of Heaviside(0)
546
+
547
+ """
548
+ if arg.is_extended_negative:
549
+ return S.Zero
550
+ elif arg.is_extended_positive:
551
+ return S.One
552
+ elif arg.is_zero:
553
+ return H0
554
+ elif arg is S.NaN:
555
+ return S.NaN
556
+ elif fuzzy_not(im(arg).is_zero):
557
+ raise ValueError("Function defined only for Real Values. Complex part: %s found in %s ." % (repr(im(arg)), repr(arg)) )
558
+
559
+ def _eval_rewrite_as_Piecewise(self, arg, H0=None, **kwargs):
560
+ """
561
+ Represents Heaviside in a Piecewise form.
562
+
563
+ Examples
564
+ ========
565
+
566
+ >>> from sympy import Heaviside, Piecewise, Symbol, nan
567
+ >>> x = Symbol('x')
568
+
569
+ >>> Heaviside(x).rewrite(Piecewise)
570
+ Piecewise((0, x < 0), (1/2, Eq(x, 0)), (1, True))
571
+
572
+ >>> Heaviside(x,nan).rewrite(Piecewise)
573
+ Piecewise((0, x < 0), (nan, Eq(x, 0)), (1, True))
574
+
575
+ >>> Heaviside(x - 5).rewrite(Piecewise)
576
+ Piecewise((0, x < 5), (1/2, Eq(x, 5)), (1, True))
577
+
578
+ >>> Heaviside(x**2 - 1).rewrite(Piecewise)
579
+ Piecewise((0, x**2 < 1), (1/2, Eq(x**2, 1)), (1, True))
580
+
581
+ """
582
+ if H0 == 0:
583
+ return Piecewise((0, arg <= 0), (1, True))
584
+ if H0 == 1:
585
+ return Piecewise((0, arg < 0), (1, True))
586
+ return Piecewise((0, arg < 0), (H0, Eq(arg, 0)), (1, True))
587
+
588
+ def _eval_rewrite_as_sign(self, arg, H0=S.Half, **kwargs):
589
+ """
590
+ Represents the Heaviside function in the form of sign function.
591
+
592
+ Explanation
593
+ ===========
594
+
595
+ The value of Heaviside(0) must be 1/2 for rewriting as sign to be
596
+ strictly equivalent. For easier usage, we also allow this rewriting
597
+ when Heaviside(0) is undefined.
598
+
599
+ Examples
600
+ ========
601
+
602
+ >>> from sympy import Heaviside, Symbol, sign, nan
603
+ >>> x = Symbol('x', real=True)
604
+ >>> y = Symbol('y')
605
+
606
+ >>> Heaviside(x).rewrite(sign)
607
+ sign(x)/2 + 1/2
608
+
609
+ >>> Heaviside(x, 0).rewrite(sign)
610
+ Piecewise((sign(x)/2 + 1/2, Ne(x, 0)), (0, True))
611
+
612
+ >>> Heaviside(x, nan).rewrite(sign)
613
+ Piecewise((sign(x)/2 + 1/2, Ne(x, 0)), (nan, True))
614
+
615
+ >>> Heaviside(x - 2).rewrite(sign)
616
+ sign(x - 2)/2 + 1/2
617
+
618
+ >>> Heaviside(x**2 - 2*x + 1).rewrite(sign)
619
+ sign(x**2 - 2*x + 1)/2 + 1/2
620
+
621
+ >>> Heaviside(y).rewrite(sign)
622
+ Heaviside(y)
623
+
624
+ >>> Heaviside(y**2 - 2*y + 1).rewrite(sign)
625
+ Heaviside(y**2 - 2*y + 1)
626
+
627
+ See Also
628
+ ========
629
+
630
+ sign
631
+
632
+ """
633
+ if arg.is_extended_real:
634
+ pw1 = Piecewise(
635
+ ((sign(arg) + 1)/2, Ne(arg, 0)),
636
+ (Heaviside(0, H0=H0), True))
637
+ pw2 = Piecewise(
638
+ ((sign(arg) + 1)/2, Eq(Heaviside(0, H0=H0), S.Half)),
639
+ (pw1, True))
640
+ return pw2
641
+
642
+ def _eval_rewrite_as_SingularityFunction(self, args, H0=S.Half, **kwargs):
643
+ """
644
+ Returns the Heaviside expression written in the form of Singularity
645
+ Functions.
646
+
647
+ """
648
+ from sympy.solvers import solve
649
+ from sympy.functions.special.singularity_functions import SingularityFunction
650
+ if self == Heaviside(0):
651
+ return SingularityFunction(0, 0, 0)
652
+ free = self.free_symbols
653
+ if len(free) == 1:
654
+ x = (free.pop())
655
+ return SingularityFunction(x, solve(args, x)[0], 0)
656
+ # TODO
657
+ # ((x - 5)**3*Heaviside(x - 5)).rewrite(SingularityFunction) should output
658
+ # SingularityFunction(x, 5, 0) instead of (x - 5)**3*SingularityFunction(x, 5, 0)
659
+ else:
660
+ # I don't know how to handle the case for Heaviside expressions
661
+ # having arguments with more than one variable.
662
+ raise TypeError(filldedent('''
663
+ rewrite(SingularityFunction) does not
664
+ support arguments with more that one variable.'''))
env-llmeval/lib/python3.10/site-packages/sympy/functions/special/elliptic_integrals.py ADDED
@@ -0,0 +1,445 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ """ Elliptic Integrals. """
2
+
3
+ from sympy.core import S, pi, I, Rational
4
+ from sympy.core.function import Function, ArgumentIndexError
5
+ from sympy.core.symbol import Dummy
6
+ from sympy.functions.elementary.complexes import sign
7
+ from sympy.functions.elementary.hyperbolic import atanh
8
+ from sympy.functions.elementary.miscellaneous import sqrt
9
+ from sympy.functions.elementary.trigonometric import sin, tan
10
+ from sympy.functions.special.gamma_functions import gamma
11
+ from sympy.functions.special.hyper import hyper, meijerg
12
+
13
+ class elliptic_k(Function):
14
+ r"""
15
+ The complete elliptic integral of the first kind, defined by
16
+
17
+ .. math:: K(m) = F\left(\tfrac{\pi}{2}\middle| m\right)
18
+
19
+ where $F\left(z\middle| m\right)$ is the Legendre incomplete
20
+ elliptic integral of the first kind.
21
+
22
+ Explanation
23
+ ===========
24
+
25
+ The function $K(m)$ is a single-valued function on the complex
26
+ plane with branch cut along the interval $(1, \infty)$.
27
+
28
+ Note that our notation defines the incomplete elliptic integral
29
+ in terms of the parameter $m$ instead of the elliptic modulus
30
+ (eccentricity) $k$.
31
+ In this case, the parameter $m$ is defined as $m=k^2$.
32
+
33
+ Examples
34
+ ========
35
+
36
+ >>> from sympy import elliptic_k, I
37
+ >>> from sympy.abc import m
38
+ >>> elliptic_k(0)
39
+ pi/2
40
+ >>> elliptic_k(1.0 + I)
41
+ 1.50923695405127 + 0.625146415202697*I
42
+ >>> elliptic_k(m).series(n=3)
43
+ pi/2 + pi*m/8 + 9*pi*m**2/128 + O(m**3)
44
+
45
+ See Also
46
+ ========
47
+
48
+ elliptic_f
49
+
50
+ References
51
+ ==========
52
+
53
+ .. [1] https://en.wikipedia.org/wiki/Elliptic_integrals
54
+ .. [2] https://functions.wolfram.com/EllipticIntegrals/EllipticK
55
+
56
+ """
57
+
58
+ @classmethod
59
+ def eval(cls, m):
60
+ if m.is_zero:
61
+ return pi*S.Half
62
+ elif m is S.Half:
63
+ return 8*pi**Rational(3, 2)/gamma(Rational(-1, 4))**2
64
+ elif m is S.One:
65
+ return S.ComplexInfinity
66
+ elif m is S.NegativeOne:
67
+ return gamma(Rational(1, 4))**2/(4*sqrt(2*pi))
68
+ elif m in (S.Infinity, S.NegativeInfinity, I*S.Infinity,
69
+ I*S.NegativeInfinity, S.ComplexInfinity):
70
+ return S.Zero
71
+
72
+ def fdiff(self, argindex=1):
73
+ m = self.args[0]
74
+ return (elliptic_e(m) - (1 - m)*elliptic_k(m))/(2*m*(1 - m))
75
+
76
+ def _eval_conjugate(self):
77
+ m = self.args[0]
78
+ if (m.is_real and (m - 1).is_positive) is False:
79
+ return self.func(m.conjugate())
80
+
81
+ def _eval_nseries(self, x, n, logx, cdir=0):
82
+ from sympy.simplify import hyperexpand
83
+ return hyperexpand(self.rewrite(hyper)._eval_nseries(x, n=n, logx=logx))
84
+
85
+ def _eval_rewrite_as_hyper(self, m, **kwargs):
86
+ return pi*S.Half*hyper((S.Half, S.Half), (S.One,), m)
87
+
88
+ def _eval_rewrite_as_meijerg(self, m, **kwargs):
89
+ return meijerg(((S.Half, S.Half), []), ((S.Zero,), (S.Zero,)), -m)/2
90
+
91
+ def _eval_is_zero(self):
92
+ m = self.args[0]
93
+ if m.is_infinite:
94
+ return True
95
+
96
+ def _eval_rewrite_as_Integral(self, *args):
97
+ from sympy.integrals.integrals import Integral
98
+ t = Dummy('t')
99
+ m = self.args[0]
100
+ return Integral(1/sqrt(1 - m*sin(t)**2), (t, 0, pi/2))
101
+
102
+
103
+ class elliptic_f(Function):
104
+ r"""
105
+ The Legendre incomplete elliptic integral of the first
106
+ kind, defined by
107
+
108
+ .. math:: F\left(z\middle| m\right) =
109
+ \int_0^z \frac{dt}{\sqrt{1 - m \sin^2 t}}
110
+
111
+ Explanation
112
+ ===========
113
+
114
+ This function reduces to a complete elliptic integral of
115
+ the first kind, $K(m)$, when $z = \pi/2$.
116
+
117
+ Note that our notation defines the incomplete elliptic integral
118
+ in terms of the parameter $m$ instead of the elliptic modulus
119
+ (eccentricity) $k$.
120
+ In this case, the parameter $m$ is defined as $m=k^2$.
121
+
122
+ Examples
123
+ ========
124
+
125
+ >>> from sympy import elliptic_f, I
126
+ >>> from sympy.abc import z, m
127
+ >>> elliptic_f(z, m).series(z)
128
+ z + z**5*(3*m**2/40 - m/30) + m*z**3/6 + O(z**6)
129
+ >>> elliptic_f(3.0 + I/2, 1.0 + I)
130
+ 2.909449841483 + 1.74720545502474*I
131
+
132
+ See Also
133
+ ========
134
+
135
+ elliptic_k
136
+
137
+ References
138
+ ==========
139
+
140
+ .. [1] https://en.wikipedia.org/wiki/Elliptic_integrals
141
+ .. [2] https://functions.wolfram.com/EllipticIntegrals/EllipticF
142
+
143
+ """
144
+
145
+ @classmethod
146
+ def eval(cls, z, m):
147
+ if z.is_zero:
148
+ return S.Zero
149
+ if m.is_zero:
150
+ return z
151
+ k = 2*z/pi
152
+ if k.is_integer:
153
+ return k*elliptic_k(m)
154
+ elif m in (S.Infinity, S.NegativeInfinity):
155
+ return S.Zero
156
+ elif z.could_extract_minus_sign():
157
+ return -elliptic_f(-z, m)
158
+
159
+ def fdiff(self, argindex=1):
160
+ z, m = self.args
161
+ fm = sqrt(1 - m*sin(z)**2)
162
+ if argindex == 1:
163
+ return 1/fm
164
+ elif argindex == 2:
165
+ return (elliptic_e(z, m)/(2*m*(1 - m)) - elliptic_f(z, m)/(2*m) -
166
+ sin(2*z)/(4*(1 - m)*fm))
167
+ raise ArgumentIndexError(self, argindex)
168
+
169
+ def _eval_conjugate(self):
170
+ z, m = self.args
171
+ if (m.is_real and (m - 1).is_positive) is False:
172
+ return self.func(z.conjugate(), m.conjugate())
173
+
174
+ def _eval_rewrite_as_Integral(self, *args):
175
+ from sympy.integrals.integrals import Integral
176
+ t = Dummy('t')
177
+ z, m = self.args[0], self.args[1]
178
+ return Integral(1/(sqrt(1 - m*sin(t)**2)), (t, 0, z))
179
+
180
+ def _eval_is_zero(self):
181
+ z, m = self.args
182
+ if z.is_zero:
183
+ return True
184
+ if m.is_extended_real and m.is_infinite:
185
+ return True
186
+
187
+
188
+ class elliptic_e(Function):
189
+ r"""
190
+ Called with two arguments $z$ and $m$, evaluates the
191
+ incomplete elliptic integral of the second kind, defined by
192
+
193
+ .. math:: E\left(z\middle| m\right) = \int_0^z \sqrt{1 - m \sin^2 t} dt
194
+
195
+ Called with a single argument $m$, evaluates the Legendre complete
196
+ elliptic integral of the second kind
197
+
198
+ .. math:: E(m) = E\left(\tfrac{\pi}{2}\middle| m\right)
199
+
200
+ Explanation
201
+ ===========
202
+
203
+ The function $E(m)$ is a single-valued function on the complex
204
+ plane with branch cut along the interval $(1, \infty)$.
205
+
206
+ Note that our notation defines the incomplete elliptic integral
207
+ in terms of the parameter $m$ instead of the elliptic modulus
208
+ (eccentricity) $k$.
209
+ In this case, the parameter $m$ is defined as $m=k^2$.
210
+
211
+ Examples
212
+ ========
213
+
214
+ >>> from sympy import elliptic_e, I
215
+ >>> from sympy.abc import z, m
216
+ >>> elliptic_e(z, m).series(z)
217
+ z + z**5*(-m**2/40 + m/30) - m*z**3/6 + O(z**6)
218
+ >>> elliptic_e(m).series(n=4)
219
+ pi/2 - pi*m/8 - 3*pi*m**2/128 - 5*pi*m**3/512 + O(m**4)
220
+ >>> elliptic_e(1 + I, 2 - I/2).n()
221
+ 1.55203744279187 + 0.290764986058437*I
222
+ >>> elliptic_e(0)
223
+ pi/2
224
+ >>> elliptic_e(2.0 - I)
225
+ 0.991052601328069 + 0.81879421395609*I
226
+
227
+ References
228
+ ==========
229
+
230
+ .. [1] https://en.wikipedia.org/wiki/Elliptic_integrals
231
+ .. [2] https://functions.wolfram.com/EllipticIntegrals/EllipticE2
232
+ .. [3] https://functions.wolfram.com/EllipticIntegrals/EllipticE
233
+
234
+ """
235
+
236
+ @classmethod
237
+ def eval(cls, m, z=None):
238
+ if z is not None:
239
+ z, m = m, z
240
+ k = 2*z/pi
241
+ if m.is_zero:
242
+ return z
243
+ if z.is_zero:
244
+ return S.Zero
245
+ elif k.is_integer:
246
+ return k*elliptic_e(m)
247
+ elif m in (S.Infinity, S.NegativeInfinity):
248
+ return S.ComplexInfinity
249
+ elif z.could_extract_minus_sign():
250
+ return -elliptic_e(-z, m)
251
+ else:
252
+ if m.is_zero:
253
+ return pi/2
254
+ elif m is S.One:
255
+ return S.One
256
+ elif m is S.Infinity:
257
+ return I*S.Infinity
258
+ elif m is S.NegativeInfinity:
259
+ return S.Infinity
260
+ elif m is S.ComplexInfinity:
261
+ return S.ComplexInfinity
262
+
263
+ def fdiff(self, argindex=1):
264
+ if len(self.args) == 2:
265
+ z, m = self.args
266
+ if argindex == 1:
267
+ return sqrt(1 - m*sin(z)**2)
268
+ elif argindex == 2:
269
+ return (elliptic_e(z, m) - elliptic_f(z, m))/(2*m)
270
+ else:
271
+ m = self.args[0]
272
+ if argindex == 1:
273
+ return (elliptic_e(m) - elliptic_k(m))/(2*m)
274
+ raise ArgumentIndexError(self, argindex)
275
+
276
+ def _eval_conjugate(self):
277
+ if len(self.args) == 2:
278
+ z, m = self.args
279
+ if (m.is_real and (m - 1).is_positive) is False:
280
+ return self.func(z.conjugate(), m.conjugate())
281
+ else:
282
+ m = self.args[0]
283
+ if (m.is_real and (m - 1).is_positive) is False:
284
+ return self.func(m.conjugate())
285
+
286
+ def _eval_nseries(self, x, n, logx, cdir=0):
287
+ from sympy.simplify import hyperexpand
288
+ if len(self.args) == 1:
289
+ return hyperexpand(self.rewrite(hyper)._eval_nseries(x, n=n, logx=logx))
290
+ return super()._eval_nseries(x, n=n, logx=logx)
291
+
292
+ def _eval_rewrite_as_hyper(self, *args, **kwargs):
293
+ if len(args) == 1:
294
+ m = args[0]
295
+ return (pi/2)*hyper((Rational(-1, 2), S.Half), (S.One,), m)
296
+
297
+ def _eval_rewrite_as_meijerg(self, *args, **kwargs):
298
+ if len(args) == 1:
299
+ m = args[0]
300
+ return -meijerg(((S.Half, Rational(3, 2)), []), \
301
+ ((S.Zero,), (S.Zero,)), -m)/4
302
+
303
+ def _eval_rewrite_as_Integral(self, *args):
304
+ from sympy.integrals.integrals import Integral
305
+ z, m = (pi/2, self.args[0]) if len(self.args) == 1 else self.args
306
+ t = Dummy('t')
307
+ return Integral(sqrt(1 - m*sin(t)**2), (t, 0, z))
308
+
309
+
310
+ class elliptic_pi(Function):
311
+ r"""
312
+ Called with three arguments $n$, $z$ and $m$, evaluates the
313
+ Legendre incomplete elliptic integral of the third kind, defined by
314
+
315
+ .. math:: \Pi\left(n; z\middle| m\right) = \int_0^z \frac{dt}
316
+ {\left(1 - n \sin^2 t\right) \sqrt{1 - m \sin^2 t}}
317
+
318
+ Called with two arguments $n$ and $m$, evaluates the complete
319
+ elliptic integral of the third kind:
320
+
321
+ .. math:: \Pi\left(n\middle| m\right) =
322
+ \Pi\left(n; \tfrac{\pi}{2}\middle| m\right)
323
+
324
+ Explanation
325
+ ===========
326
+
327
+ Note that our notation defines the incomplete elliptic integral
328
+ in terms of the parameter $m$ instead of the elliptic modulus
329
+ (eccentricity) $k$.
330
+ In this case, the parameter $m$ is defined as $m=k^2$.
331
+
332
+ Examples
333
+ ========
334
+
335
+ >>> from sympy import elliptic_pi, I
336
+ >>> from sympy.abc import z, n, m
337
+ >>> elliptic_pi(n, z, m).series(z, n=4)
338
+ z + z**3*(m/6 + n/3) + O(z**4)
339
+ >>> elliptic_pi(0.5 + I, 1.0 - I, 1.2)
340
+ 2.50232379629182 - 0.760939574180767*I
341
+ >>> elliptic_pi(0, 0)
342
+ pi/2
343
+ >>> elliptic_pi(1.0 - I/3, 2.0 + I)
344
+ 3.29136443417283 + 0.32555634906645*I
345
+
346
+ References
347
+ ==========
348
+
349
+ .. [1] https://en.wikipedia.org/wiki/Elliptic_integrals
350
+ .. [2] https://functions.wolfram.com/EllipticIntegrals/EllipticPi3
351
+ .. [3] https://functions.wolfram.com/EllipticIntegrals/EllipticPi
352
+
353
+ """
354
+
355
+ @classmethod
356
+ def eval(cls, n, m, z=None):
357
+ if z is not None:
358
+ n, z, m = n, m, z
359
+ if n.is_zero:
360
+ return elliptic_f(z, m)
361
+ elif n is S.One:
362
+ return (elliptic_f(z, m) +
363
+ (sqrt(1 - m*sin(z)**2)*tan(z) -
364
+ elliptic_e(z, m))/(1 - m))
365
+ k = 2*z/pi
366
+ if k.is_integer:
367
+ return k*elliptic_pi(n, m)
368
+ elif m.is_zero:
369
+ return atanh(sqrt(n - 1)*tan(z))/sqrt(n - 1)
370
+ elif n == m:
371
+ return (elliptic_f(z, n) - elliptic_pi(1, z, n) +
372
+ tan(z)/sqrt(1 - n*sin(z)**2))
373
+ elif n in (S.Infinity, S.NegativeInfinity):
374
+ return S.Zero
375
+ elif m in (S.Infinity, S.NegativeInfinity):
376
+ return S.Zero
377
+ elif z.could_extract_minus_sign():
378
+ return -elliptic_pi(n, -z, m)
379
+ if n.is_zero:
380
+ return elliptic_f(z, m)
381
+ if m.is_extended_real and m.is_infinite or \
382
+ n.is_extended_real and n.is_infinite:
383
+ return S.Zero
384
+ else:
385
+ if n.is_zero:
386
+ return elliptic_k(m)
387
+ elif n is S.One:
388
+ return S.ComplexInfinity
389
+ elif m.is_zero:
390
+ return pi/(2*sqrt(1 - n))
391
+ elif m == S.One:
392
+ return S.NegativeInfinity/sign(n - 1)
393
+ elif n == m:
394
+ return elliptic_e(n)/(1 - n)
395
+ elif n in (S.Infinity, S.NegativeInfinity):
396
+ return S.Zero
397
+ elif m in (S.Infinity, S.NegativeInfinity):
398
+ return S.Zero
399
+ if n.is_zero:
400
+ return elliptic_k(m)
401
+ if m.is_extended_real and m.is_infinite or \
402
+ n.is_extended_real and n.is_infinite:
403
+ return S.Zero
404
+
405
+ def _eval_conjugate(self):
406
+ if len(self.args) == 3:
407
+ n, z, m = self.args
408
+ if (n.is_real and (n - 1).is_positive) is False and \
409
+ (m.is_real and (m - 1).is_positive) is False:
410
+ return self.func(n.conjugate(), z.conjugate(), m.conjugate())
411
+ else:
412
+ n, m = self.args
413
+ return self.func(n.conjugate(), m.conjugate())
414
+
415
+ def fdiff(self, argindex=1):
416
+ if len(self.args) == 3:
417
+ n, z, m = self.args
418
+ fm, fn = sqrt(1 - m*sin(z)**2), 1 - n*sin(z)**2
419
+ if argindex == 1:
420
+ return (elliptic_e(z, m) + (m - n)*elliptic_f(z, m)/n +
421
+ (n**2 - m)*elliptic_pi(n, z, m)/n -
422
+ n*fm*sin(2*z)/(2*fn))/(2*(m - n)*(n - 1))
423
+ elif argindex == 2:
424
+ return 1/(fm*fn)
425
+ elif argindex == 3:
426
+ return (elliptic_e(z, m)/(m - 1) +
427
+ elliptic_pi(n, z, m) -
428
+ m*sin(2*z)/(2*(m - 1)*fm))/(2*(n - m))
429
+ else:
430
+ n, m = self.args
431
+ if argindex == 1:
432
+ return (elliptic_e(m) + (m - n)*elliptic_k(m)/n +
433
+ (n**2 - m)*elliptic_pi(n, m)/n)/(2*(m - n)*(n - 1))
434
+ elif argindex == 2:
435
+ return (elliptic_e(m)/(m - 1) + elliptic_pi(n, m))/(2*(n - m))
436
+ raise ArgumentIndexError(self, argindex)
437
+
438
+ def _eval_rewrite_as_Integral(self, *args):
439
+ from sympy.integrals.integrals import Integral
440
+ if len(self.args) == 2:
441
+ n, m, z = self.args[0], self.args[1], pi/2
442
+ else:
443
+ n, z, m = self.args
444
+ t = Dummy('t')
445
+ return Integral(1/((1 - n*sin(t)**2)*sqrt(1 - m*sin(t)**2)), (t, 0, z))
env-llmeval/lib/python3.10/site-packages/sympy/functions/special/error_functions.py ADDED
@@ -0,0 +1,2741 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ """ This module contains various functions that are special cases
2
+ of incomplete gamma functions. It should probably be renamed. """
3
+
4
+ from sympy.core import EulerGamma # Must be imported from core, not core.numbers
5
+ from sympy.core.add import Add
6
+ from sympy.core.cache import cacheit
7
+ from sympy.core.function import Function, ArgumentIndexError, expand_mul
8
+ from sympy.core.numbers import I, pi, Rational
9
+ from sympy.core.relational import is_eq
10
+ from sympy.core.power import Pow
11
+ from sympy.core.singleton import S
12
+ from sympy.core.symbol import Symbol
13
+ from sympy.core.sympify import sympify
14
+ from sympy.functions.combinatorial.factorials import factorial, factorial2, RisingFactorial
15
+ from sympy.functions.elementary.complexes import polar_lift, re, unpolarify
16
+ from sympy.functions.elementary.integers import ceiling, floor
17
+ from sympy.functions.elementary.miscellaneous import sqrt, root
18
+ from sympy.functions.elementary.exponential import exp, log, exp_polar
19
+ from sympy.functions.elementary.hyperbolic import cosh, sinh
20
+ from sympy.functions.elementary.trigonometric import cos, sin, sinc
21
+ from sympy.functions.special.hyper import hyper, meijerg
22
+
23
+ # TODO series expansions
24
+ # TODO see the "Note:" in Ei
25
+
26
+ # Helper function
27
+ def real_to_real_as_real_imag(self, deep=True, **hints):
28
+ if self.args[0].is_extended_real:
29
+ if deep:
30
+ hints['complex'] = False
31
+ return (self.expand(deep, **hints), S.Zero)
32
+ else:
33
+ return (self, S.Zero)
34
+ if deep:
35
+ x, y = self.args[0].expand(deep, **hints).as_real_imag()
36
+ else:
37
+ x, y = self.args[0].as_real_imag()
38
+ re = (self.func(x + I*y) + self.func(x - I*y))/2
39
+ im = (self.func(x + I*y) - self.func(x - I*y))/(2*I)
40
+ return (re, im)
41
+
42
+
43
+ ###############################################################################
44
+ ################################ ERROR FUNCTION ###############################
45
+ ###############################################################################
46
+
47
+
48
+ class erf(Function):
49
+ r"""
50
+ The Gauss error function.
51
+
52
+ Explanation
53
+ ===========
54
+
55
+ This function is defined as:
56
+
57
+ .. math ::
58
+ \mathrm{erf}(x) = \frac{2}{\sqrt{\pi}} \int_0^x e^{-t^2} \mathrm{d}t.
59
+
60
+ Examples
61
+ ========
62
+
63
+ >>> from sympy import I, oo, erf
64
+ >>> from sympy.abc import z
65
+
66
+ Several special values are known:
67
+
68
+ >>> erf(0)
69
+ 0
70
+ >>> erf(oo)
71
+ 1
72
+ >>> erf(-oo)
73
+ -1
74
+ >>> erf(I*oo)
75
+ oo*I
76
+ >>> erf(-I*oo)
77
+ -oo*I
78
+
79
+ In general one can pull out factors of -1 and $I$ from the argument:
80
+
81
+ >>> erf(-z)
82
+ -erf(z)
83
+
84
+ The error function obeys the mirror symmetry:
85
+
86
+ >>> from sympy import conjugate
87
+ >>> conjugate(erf(z))
88
+ erf(conjugate(z))
89
+
90
+ Differentiation with respect to $z$ is supported:
91
+
92
+ >>> from sympy import diff
93
+ >>> diff(erf(z), z)
94
+ 2*exp(-z**2)/sqrt(pi)
95
+
96
+ We can numerically evaluate the error function to arbitrary precision
97
+ on the whole complex plane:
98
+
99
+ >>> erf(4).evalf(30)
100
+ 0.999999984582742099719981147840
101
+
102
+ >>> erf(-4*I).evalf(30)
103
+ -1296959.73071763923152794095062*I
104
+
105
+ See Also
106
+ ========
107
+
108
+ erfc: Complementary error function.
109
+ erfi: Imaginary error function.
110
+ erf2: Two-argument error function.
111
+ erfinv: Inverse error function.
112
+ erfcinv: Inverse Complementary error function.
113
+ erf2inv: Inverse two-argument error function.
114
+
115
+ References
116
+ ==========
117
+
118
+ .. [1] https://en.wikipedia.org/wiki/Error_function
119
+ .. [2] https://dlmf.nist.gov/7
120
+ .. [3] https://mathworld.wolfram.com/Erf.html
121
+ .. [4] https://functions.wolfram.com/GammaBetaErf/Erf
122
+
123
+ """
124
+
125
+ unbranched = True
126
+
127
+ def fdiff(self, argindex=1):
128
+ if argindex == 1:
129
+ return 2*exp(-self.args[0]**2)/sqrt(pi)
130
+ else:
131
+ raise ArgumentIndexError(self, argindex)
132
+
133
+
134
+ def inverse(self, argindex=1):
135
+ """
136
+ Returns the inverse of this function.
137
+
138
+ """
139
+ return erfinv
140
+
141
+ @classmethod
142
+ def eval(cls, arg):
143
+ if arg.is_Number:
144
+ if arg is S.NaN:
145
+ return S.NaN
146
+ elif arg is S.Infinity:
147
+ return S.One
148
+ elif arg is S.NegativeInfinity:
149
+ return S.NegativeOne
150
+ elif arg.is_zero:
151
+ return S.Zero
152
+
153
+ if isinstance(arg, erfinv):
154
+ return arg.args[0]
155
+
156
+ if isinstance(arg, erfcinv):
157
+ return S.One - arg.args[0]
158
+
159
+ if arg.is_zero:
160
+ return S.Zero
161
+
162
+ # Only happens with unevaluated erf2inv
163
+ if isinstance(arg, erf2inv) and arg.args[0].is_zero:
164
+ return arg.args[1]
165
+
166
+ # Try to pull out factors of I
167
+ t = arg.extract_multiplicatively(I)
168
+ if t in (S.Infinity, S.NegativeInfinity):
169
+ return arg
170
+
171
+ # Try to pull out factors of -1
172
+ if arg.could_extract_minus_sign():
173
+ return -cls(-arg)
174
+
175
+ @staticmethod
176
+ @cacheit
177
+ def taylor_term(n, x, *previous_terms):
178
+ if n < 0 or n % 2 == 0:
179
+ return S.Zero
180
+ else:
181
+ x = sympify(x)
182
+ k = floor((n - 1)/S(2))
183
+ if len(previous_terms) > 2:
184
+ return -previous_terms[-2] * x**2 * (n - 2)/(n*k)
185
+ else:
186
+ return 2*S.NegativeOne**k * x**n/(n*factorial(k)*sqrt(pi))
187
+
188
+ def _eval_conjugate(self):
189
+ return self.func(self.args[0].conjugate())
190
+
191
+ def _eval_is_real(self):
192
+ return self.args[0].is_extended_real
193
+
194
+ def _eval_is_finite(self):
195
+ if self.args[0].is_finite:
196
+ return True
197
+ else:
198
+ return self.args[0].is_extended_real
199
+
200
+ def _eval_is_zero(self):
201
+ return self.args[0].is_zero
202
+
203
+ def _eval_rewrite_as_uppergamma(self, z, **kwargs):
204
+ from sympy.functions.special.gamma_functions import uppergamma
205
+ return sqrt(z**2)/z*(S.One - uppergamma(S.Half, z**2)/sqrt(pi))
206
+
207
+ def _eval_rewrite_as_fresnels(self, z, **kwargs):
208
+ arg = (S.One - I)*z/sqrt(pi)
209
+ return (S.One + I)*(fresnelc(arg) - I*fresnels(arg))
210
+
211
+ def _eval_rewrite_as_fresnelc(self, z, **kwargs):
212
+ arg = (S.One - I)*z/sqrt(pi)
213
+ return (S.One + I)*(fresnelc(arg) - I*fresnels(arg))
214
+
215
+ def _eval_rewrite_as_meijerg(self, z, **kwargs):
216
+ return z/sqrt(pi)*meijerg([S.Half], [], [0], [Rational(-1, 2)], z**2)
217
+
218
+ def _eval_rewrite_as_hyper(self, z, **kwargs):
219
+ return 2*z/sqrt(pi)*hyper([S.Half], [3*S.Half], -z**2)
220
+
221
+ def _eval_rewrite_as_expint(self, z, **kwargs):
222
+ return sqrt(z**2)/z - z*expint(S.Half, z**2)/sqrt(pi)
223
+
224
+ def _eval_rewrite_as_tractable(self, z, limitvar=None, **kwargs):
225
+ from sympy.series.limits import limit
226
+ if limitvar:
227
+ lim = limit(z, limitvar, S.Infinity)
228
+ if lim is S.NegativeInfinity:
229
+ return S.NegativeOne + _erfs(-z)*exp(-z**2)
230
+ return S.One - _erfs(z)*exp(-z**2)
231
+
232
+ def _eval_rewrite_as_erfc(self, z, **kwargs):
233
+ return S.One - erfc(z)
234
+
235
+ def _eval_rewrite_as_erfi(self, z, **kwargs):
236
+ return -I*erfi(I*z)
237
+
238
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
239
+ arg = self.args[0].as_leading_term(x, logx=logx, cdir=cdir)
240
+ arg0 = arg.subs(x, 0)
241
+
242
+ if arg0 is S.ComplexInfinity:
243
+ arg0 = arg.limit(x, 0, dir='-' if cdir == -1 else '+')
244
+ if x in arg.free_symbols and arg0.is_zero:
245
+ return 2*arg/sqrt(pi)
246
+ else:
247
+ return self.func(arg0)
248
+
249
+ def _eval_aseries(self, n, args0, x, logx):
250
+ from sympy.series.order import Order
251
+ point = args0[0]
252
+
253
+ if point in [S.Infinity, S.NegativeInfinity]:
254
+ z = self.args[0]
255
+
256
+ try:
257
+ _, ex = z.leadterm(x)
258
+ except (ValueError, NotImplementedError):
259
+ return self
260
+
261
+ ex = -ex # as x->1/x for aseries
262
+ if ex.is_positive:
263
+ newn = ceiling(n/ex)
264
+ s = [S.NegativeOne**k * factorial2(2*k - 1) / (z**(2*k + 1) * 2**k)
265
+ for k in range(newn)] + [Order(1/z**newn, x)]
266
+ return S.One - (exp(-z**2)/sqrt(pi)) * Add(*s)
267
+
268
+ return super(erf, self)._eval_aseries(n, args0, x, logx)
269
+
270
+ as_real_imag = real_to_real_as_real_imag
271
+
272
+
273
+ class erfc(Function):
274
+ r"""
275
+ Complementary Error Function.
276
+
277
+ Explanation
278
+ ===========
279
+
280
+ The function is defined as:
281
+
282
+ .. math ::
283
+ \mathrm{erfc}(x) = \frac{2}{\sqrt{\pi}} \int_x^\infty e^{-t^2} \mathrm{d}t
284
+
285
+ Examples
286
+ ========
287
+
288
+ >>> from sympy import I, oo, erfc
289
+ >>> from sympy.abc import z
290
+
291
+ Several special values are known:
292
+
293
+ >>> erfc(0)
294
+ 1
295
+ >>> erfc(oo)
296
+ 0
297
+ >>> erfc(-oo)
298
+ 2
299
+ >>> erfc(I*oo)
300
+ -oo*I
301
+ >>> erfc(-I*oo)
302
+ oo*I
303
+
304
+ The error function obeys the mirror symmetry:
305
+
306
+ >>> from sympy import conjugate
307
+ >>> conjugate(erfc(z))
308
+ erfc(conjugate(z))
309
+
310
+ Differentiation with respect to $z$ is supported:
311
+
312
+ >>> from sympy import diff
313
+ >>> diff(erfc(z), z)
314
+ -2*exp(-z**2)/sqrt(pi)
315
+
316
+ It also follows
317
+
318
+ >>> erfc(-z)
319
+ 2 - erfc(z)
320
+
321
+ We can numerically evaluate the complementary error function to arbitrary
322
+ precision on the whole complex plane:
323
+
324
+ >>> erfc(4).evalf(30)
325
+ 0.0000000154172579002800188521596734869
326
+
327
+ >>> erfc(4*I).evalf(30)
328
+ 1.0 - 1296959.73071763923152794095062*I
329
+
330
+ See Also
331
+ ========
332
+
333
+ erf: Gaussian error function.
334
+ erfi: Imaginary error function.
335
+ erf2: Two-argument error function.
336
+ erfinv: Inverse error function.
337
+ erfcinv: Inverse Complementary error function.
338
+ erf2inv: Inverse two-argument error function.
339
+
340
+ References
341
+ ==========
342
+
343
+ .. [1] https://en.wikipedia.org/wiki/Error_function
344
+ .. [2] https://dlmf.nist.gov/7
345
+ .. [3] https://mathworld.wolfram.com/Erfc.html
346
+ .. [4] https://functions.wolfram.com/GammaBetaErf/Erfc
347
+
348
+ """
349
+
350
+ unbranched = True
351
+
352
+ def fdiff(self, argindex=1):
353
+ if argindex == 1:
354
+ return -2*exp(-self.args[0]**2)/sqrt(pi)
355
+ else:
356
+ raise ArgumentIndexError(self, argindex)
357
+
358
+ def inverse(self, argindex=1):
359
+ """
360
+ Returns the inverse of this function.
361
+
362
+ """
363
+ return erfcinv
364
+
365
+ @classmethod
366
+ def eval(cls, arg):
367
+ if arg.is_Number:
368
+ if arg is S.NaN:
369
+ return S.NaN
370
+ elif arg is S.Infinity:
371
+ return S.Zero
372
+ elif arg.is_zero:
373
+ return S.One
374
+
375
+ if isinstance(arg, erfinv):
376
+ return S.One - arg.args[0]
377
+
378
+ if isinstance(arg, erfcinv):
379
+ return arg.args[0]
380
+
381
+ if arg.is_zero:
382
+ return S.One
383
+
384
+ # Try to pull out factors of I
385
+ t = arg.extract_multiplicatively(I)
386
+ if t in (S.Infinity, S.NegativeInfinity):
387
+ return -arg
388
+
389
+ # Try to pull out factors of -1
390
+ if arg.could_extract_minus_sign():
391
+ return 2 - cls(-arg)
392
+
393
+ @staticmethod
394
+ @cacheit
395
+ def taylor_term(n, x, *previous_terms):
396
+ if n == 0:
397
+ return S.One
398
+ elif n < 0 or n % 2 == 0:
399
+ return S.Zero
400
+ else:
401
+ x = sympify(x)
402
+ k = floor((n - 1)/S(2))
403
+ if len(previous_terms) > 2:
404
+ return -previous_terms[-2] * x**2 * (n - 2)/(n*k)
405
+ else:
406
+ return -2*S.NegativeOne**k * x**n/(n*factorial(k)*sqrt(pi))
407
+
408
+ def _eval_conjugate(self):
409
+ return self.func(self.args[0].conjugate())
410
+
411
+ def _eval_is_real(self):
412
+ return self.args[0].is_extended_real
413
+
414
+ def _eval_rewrite_as_tractable(self, z, limitvar=None, **kwargs):
415
+ return self.rewrite(erf).rewrite("tractable", deep=True, limitvar=limitvar)
416
+
417
+ def _eval_rewrite_as_erf(self, z, **kwargs):
418
+ return S.One - erf(z)
419
+
420
+ def _eval_rewrite_as_erfi(self, z, **kwargs):
421
+ return S.One + I*erfi(I*z)
422
+
423
+ def _eval_rewrite_as_fresnels(self, z, **kwargs):
424
+ arg = (S.One - I)*z/sqrt(pi)
425
+ return S.One - (S.One + I)*(fresnelc(arg) - I*fresnels(arg))
426
+
427
+ def _eval_rewrite_as_fresnelc(self, z, **kwargs):
428
+ arg = (S.One-I)*z/sqrt(pi)
429
+ return S.One - (S.One + I)*(fresnelc(arg) - I*fresnels(arg))
430
+
431
+ def _eval_rewrite_as_meijerg(self, z, **kwargs):
432
+ return S.One - z/sqrt(pi)*meijerg([S.Half], [], [0], [Rational(-1, 2)], z**2)
433
+
434
+ def _eval_rewrite_as_hyper(self, z, **kwargs):
435
+ return S.One - 2*z/sqrt(pi)*hyper([S.Half], [3*S.Half], -z**2)
436
+
437
+ def _eval_rewrite_as_uppergamma(self, z, **kwargs):
438
+ from sympy.functions.special.gamma_functions import uppergamma
439
+ return S.One - sqrt(z**2)/z*(S.One - uppergamma(S.Half, z**2)/sqrt(pi))
440
+
441
+ def _eval_rewrite_as_expint(self, z, **kwargs):
442
+ return S.One - sqrt(z**2)/z + z*expint(S.Half, z**2)/sqrt(pi)
443
+
444
+ def _eval_expand_func(self, **hints):
445
+ return self.rewrite(erf)
446
+
447
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
448
+ arg = self.args[0].as_leading_term(x, logx=logx, cdir=cdir)
449
+ arg0 = arg.subs(x, 0)
450
+
451
+ if arg0 is S.ComplexInfinity:
452
+ arg0 = arg.limit(x, 0, dir='-' if cdir == -1 else '+')
453
+ if arg0.is_zero:
454
+ return S.One
455
+ else:
456
+ return self.func(arg0)
457
+
458
+ as_real_imag = real_to_real_as_real_imag
459
+
460
+ def _eval_aseries(self, n, args0, x, logx):
461
+ return S.One - erf(*self.args)._eval_aseries(n, args0, x, logx)
462
+
463
+
464
+ class erfi(Function):
465
+ r"""
466
+ Imaginary error function.
467
+
468
+ Explanation
469
+ ===========
470
+
471
+ The function erfi is defined as:
472
+
473
+ .. math ::
474
+ \mathrm{erfi}(x) = \frac{2}{\sqrt{\pi}} \int_0^x e^{t^2} \mathrm{d}t
475
+
476
+ Examples
477
+ ========
478
+
479
+ >>> from sympy import I, oo, erfi
480
+ >>> from sympy.abc import z
481
+
482
+ Several special values are known:
483
+
484
+ >>> erfi(0)
485
+ 0
486
+ >>> erfi(oo)
487
+ oo
488
+ >>> erfi(-oo)
489
+ -oo
490
+ >>> erfi(I*oo)
491
+ I
492
+ >>> erfi(-I*oo)
493
+ -I
494
+
495
+ In general one can pull out factors of -1 and $I$ from the argument:
496
+
497
+ >>> erfi(-z)
498
+ -erfi(z)
499
+
500
+ >>> from sympy import conjugate
501
+ >>> conjugate(erfi(z))
502
+ erfi(conjugate(z))
503
+
504
+ Differentiation with respect to $z$ is supported:
505
+
506
+ >>> from sympy import diff
507
+ >>> diff(erfi(z), z)
508
+ 2*exp(z**2)/sqrt(pi)
509
+
510
+ We can numerically evaluate the imaginary error function to arbitrary
511
+ precision on the whole complex plane:
512
+
513
+ >>> erfi(2).evalf(30)
514
+ 18.5648024145755525987042919132
515
+
516
+ >>> erfi(-2*I).evalf(30)
517
+ -0.995322265018952734162069256367*I
518
+
519
+ See Also
520
+ ========
521
+
522
+ erf: Gaussian error function.
523
+ erfc: Complementary error function.
524
+ erf2: Two-argument error function.
525
+ erfinv: Inverse error function.
526
+ erfcinv: Inverse Complementary error function.
527
+ erf2inv: Inverse two-argument error function.
528
+
529
+ References
530
+ ==========
531
+
532
+ .. [1] https://en.wikipedia.org/wiki/Error_function
533
+ .. [2] https://mathworld.wolfram.com/Erfi.html
534
+ .. [3] https://functions.wolfram.com/GammaBetaErf/Erfi
535
+
536
+ """
537
+
538
+ unbranched = True
539
+
540
+ def fdiff(self, argindex=1):
541
+ if argindex == 1:
542
+ return 2*exp(self.args[0]**2)/sqrt(pi)
543
+ else:
544
+ raise ArgumentIndexError(self, argindex)
545
+
546
+ @classmethod
547
+ def eval(cls, z):
548
+ if z.is_Number:
549
+ if z is S.NaN:
550
+ return S.NaN
551
+ elif z.is_zero:
552
+ return S.Zero
553
+ elif z is S.Infinity:
554
+ return S.Infinity
555
+
556
+ if z.is_zero:
557
+ return S.Zero
558
+
559
+ # Try to pull out factors of -1
560
+ if z.could_extract_minus_sign():
561
+ return -cls(-z)
562
+
563
+ # Try to pull out factors of I
564
+ nz = z.extract_multiplicatively(I)
565
+ if nz is not None:
566
+ if nz is S.Infinity:
567
+ return I
568
+ if isinstance(nz, erfinv):
569
+ return I*nz.args[0]
570
+ if isinstance(nz, erfcinv):
571
+ return I*(S.One - nz.args[0])
572
+ # Only happens with unevaluated erf2inv
573
+ if isinstance(nz, erf2inv) and nz.args[0].is_zero:
574
+ return I*nz.args[1]
575
+
576
+ @staticmethod
577
+ @cacheit
578
+ def taylor_term(n, x, *previous_terms):
579
+ if n < 0 or n % 2 == 0:
580
+ return S.Zero
581
+ else:
582
+ x = sympify(x)
583
+ k = floor((n - 1)/S(2))
584
+ if len(previous_terms) > 2:
585
+ return previous_terms[-2] * x**2 * (n - 2)/(n*k)
586
+ else:
587
+ return 2 * x**n/(n*factorial(k)*sqrt(pi))
588
+
589
+ def _eval_conjugate(self):
590
+ return self.func(self.args[0].conjugate())
591
+
592
+ def _eval_is_extended_real(self):
593
+ return self.args[0].is_extended_real
594
+
595
+ def _eval_is_zero(self):
596
+ return self.args[0].is_zero
597
+
598
+ def _eval_rewrite_as_tractable(self, z, limitvar=None, **kwargs):
599
+ return self.rewrite(erf).rewrite("tractable", deep=True, limitvar=limitvar)
600
+
601
+ def _eval_rewrite_as_erf(self, z, **kwargs):
602
+ return -I*erf(I*z)
603
+
604
+ def _eval_rewrite_as_erfc(self, z, **kwargs):
605
+ return I*erfc(I*z) - I
606
+
607
+ def _eval_rewrite_as_fresnels(self, z, **kwargs):
608
+ arg = (S.One + I)*z/sqrt(pi)
609
+ return (S.One - I)*(fresnelc(arg) - I*fresnels(arg))
610
+
611
+ def _eval_rewrite_as_fresnelc(self, z, **kwargs):
612
+ arg = (S.One + I)*z/sqrt(pi)
613
+ return (S.One - I)*(fresnelc(arg) - I*fresnels(arg))
614
+
615
+ def _eval_rewrite_as_meijerg(self, z, **kwargs):
616
+ return z/sqrt(pi)*meijerg([S.Half], [], [0], [Rational(-1, 2)], -z**2)
617
+
618
+ def _eval_rewrite_as_hyper(self, z, **kwargs):
619
+ return 2*z/sqrt(pi)*hyper([S.Half], [3*S.Half], z**2)
620
+
621
+ def _eval_rewrite_as_uppergamma(self, z, **kwargs):
622
+ from sympy.functions.special.gamma_functions import uppergamma
623
+ return sqrt(-z**2)/z*(uppergamma(S.Half, -z**2)/sqrt(pi) - S.One)
624
+
625
+ def _eval_rewrite_as_expint(self, z, **kwargs):
626
+ return sqrt(-z**2)/z - z*expint(S.Half, -z**2)/sqrt(pi)
627
+
628
+ def _eval_expand_func(self, **hints):
629
+ return self.rewrite(erf)
630
+
631
+ as_real_imag = real_to_real_as_real_imag
632
+
633
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
634
+ arg = self.args[0].as_leading_term(x, logx=logx, cdir=cdir)
635
+ arg0 = arg.subs(x, 0)
636
+
637
+ if x in arg.free_symbols and arg0.is_zero:
638
+ return 2*arg/sqrt(pi)
639
+ elif arg0.is_finite:
640
+ return self.func(arg0)
641
+ return self.func(arg)
642
+
643
+ def _eval_aseries(self, n, args0, x, logx):
644
+ from sympy.series.order import Order
645
+ point = args0[0]
646
+
647
+ if point is S.Infinity:
648
+ z = self.args[0]
649
+ s = [factorial2(2*k - 1) / (2**k * z**(2*k + 1))
650
+ for k in range(n)] + [Order(1/z**n, x)]
651
+ return -I + (exp(z**2)/sqrt(pi)) * Add(*s)
652
+
653
+ return super(erfi, self)._eval_aseries(n, args0, x, logx)
654
+
655
+
656
+ class erf2(Function):
657
+ r"""
658
+ Two-argument error function.
659
+
660
+ Explanation
661
+ ===========
662
+
663
+ This function is defined as:
664
+
665
+ .. math ::
666
+ \mathrm{erf2}(x, y) = \frac{2}{\sqrt{\pi}} \int_x^y e^{-t^2} \mathrm{d}t
667
+
668
+ Examples
669
+ ========
670
+
671
+ >>> from sympy import oo, erf2
672
+ >>> from sympy.abc import x, y
673
+
674
+ Several special values are known:
675
+
676
+ >>> erf2(0, 0)
677
+ 0
678
+ >>> erf2(x, x)
679
+ 0
680
+ >>> erf2(x, oo)
681
+ 1 - erf(x)
682
+ >>> erf2(x, -oo)
683
+ -erf(x) - 1
684
+ >>> erf2(oo, y)
685
+ erf(y) - 1
686
+ >>> erf2(-oo, y)
687
+ erf(y) + 1
688
+
689
+ In general one can pull out factors of -1:
690
+
691
+ >>> erf2(-x, -y)
692
+ -erf2(x, y)
693
+
694
+ The error function obeys the mirror symmetry:
695
+
696
+ >>> from sympy import conjugate
697
+ >>> conjugate(erf2(x, y))
698
+ erf2(conjugate(x), conjugate(y))
699
+
700
+ Differentiation with respect to $x$, $y$ is supported:
701
+
702
+ >>> from sympy import diff
703
+ >>> diff(erf2(x, y), x)
704
+ -2*exp(-x**2)/sqrt(pi)
705
+ >>> diff(erf2(x, y), y)
706
+ 2*exp(-y**2)/sqrt(pi)
707
+
708
+ See Also
709
+ ========
710
+
711
+ erf: Gaussian error function.
712
+ erfc: Complementary error function.
713
+ erfi: Imaginary error function.
714
+ erfinv: Inverse error function.
715
+ erfcinv: Inverse Complementary error function.
716
+ erf2inv: Inverse two-argument error function.
717
+
718
+ References
719
+ ==========
720
+
721
+ .. [1] https://functions.wolfram.com/GammaBetaErf/Erf2/
722
+
723
+ """
724
+
725
+
726
+ def fdiff(self, argindex):
727
+ x, y = self.args
728
+ if argindex == 1:
729
+ return -2*exp(-x**2)/sqrt(pi)
730
+ elif argindex == 2:
731
+ return 2*exp(-y**2)/sqrt(pi)
732
+ else:
733
+ raise ArgumentIndexError(self, argindex)
734
+
735
+ @classmethod
736
+ def eval(cls, x, y):
737
+ chk = (S.Infinity, S.NegativeInfinity, S.Zero)
738
+ if x is S.NaN or y is S.NaN:
739
+ return S.NaN
740
+ elif x == y:
741
+ return S.Zero
742
+ elif x in chk or y in chk:
743
+ return erf(y) - erf(x)
744
+
745
+ if isinstance(y, erf2inv) and y.args[0] == x:
746
+ return y.args[1]
747
+
748
+ if x.is_zero or y.is_zero or x.is_extended_real and x.is_infinite or \
749
+ y.is_extended_real and y.is_infinite:
750
+ return erf(y) - erf(x)
751
+
752
+ #Try to pull out -1 factor
753
+ sign_x = x.could_extract_minus_sign()
754
+ sign_y = y.could_extract_minus_sign()
755
+ if (sign_x and sign_y):
756
+ return -cls(-x, -y)
757
+ elif (sign_x or sign_y):
758
+ return erf(y)-erf(x)
759
+
760
+ def _eval_conjugate(self):
761
+ return self.func(self.args[0].conjugate(), self.args[1].conjugate())
762
+
763
+ def _eval_is_extended_real(self):
764
+ return self.args[0].is_extended_real and self.args[1].is_extended_real
765
+
766
+ def _eval_rewrite_as_erf(self, x, y, **kwargs):
767
+ return erf(y) - erf(x)
768
+
769
+ def _eval_rewrite_as_erfc(self, x, y, **kwargs):
770
+ return erfc(x) - erfc(y)
771
+
772
+ def _eval_rewrite_as_erfi(self, x, y, **kwargs):
773
+ return I*(erfi(I*x)-erfi(I*y))
774
+
775
+ def _eval_rewrite_as_fresnels(self, x, y, **kwargs):
776
+ return erf(y).rewrite(fresnels) - erf(x).rewrite(fresnels)
777
+
778
+ def _eval_rewrite_as_fresnelc(self, x, y, **kwargs):
779
+ return erf(y).rewrite(fresnelc) - erf(x).rewrite(fresnelc)
780
+
781
+ def _eval_rewrite_as_meijerg(self, x, y, **kwargs):
782
+ return erf(y).rewrite(meijerg) - erf(x).rewrite(meijerg)
783
+
784
+ def _eval_rewrite_as_hyper(self, x, y, **kwargs):
785
+ return erf(y).rewrite(hyper) - erf(x).rewrite(hyper)
786
+
787
+ def _eval_rewrite_as_uppergamma(self, x, y, **kwargs):
788
+ from sympy.functions.special.gamma_functions import uppergamma
789
+ return (sqrt(y**2)/y*(S.One - uppergamma(S.Half, y**2)/sqrt(pi)) -
790
+ sqrt(x**2)/x*(S.One - uppergamma(S.Half, x**2)/sqrt(pi)))
791
+
792
+ def _eval_rewrite_as_expint(self, x, y, **kwargs):
793
+ return erf(y).rewrite(expint) - erf(x).rewrite(expint)
794
+
795
+ def _eval_expand_func(self, **hints):
796
+ return self.rewrite(erf)
797
+
798
+ def _eval_is_zero(self):
799
+ return is_eq(*self.args)
800
+
801
+ class erfinv(Function):
802
+ r"""
803
+ Inverse Error Function. The erfinv function is defined as:
804
+
805
+ .. math ::
806
+ \mathrm{erf}(x) = y \quad \Rightarrow \quad \mathrm{erfinv}(y) = x
807
+
808
+ Examples
809
+ ========
810
+
811
+ >>> from sympy import erfinv
812
+ >>> from sympy.abc import x
813
+
814
+ Several special values are known:
815
+
816
+ >>> erfinv(0)
817
+ 0
818
+ >>> erfinv(1)
819
+ oo
820
+
821
+ Differentiation with respect to $x$ is supported:
822
+
823
+ >>> from sympy import diff
824
+ >>> diff(erfinv(x), x)
825
+ sqrt(pi)*exp(erfinv(x)**2)/2
826
+
827
+ We can numerically evaluate the inverse error function to arbitrary
828
+ precision on [-1, 1]:
829
+
830
+ >>> erfinv(0.2).evalf(30)
831
+ 0.179143454621291692285822705344
832
+
833
+ See Also
834
+ ========
835
+
836
+ erf: Gaussian error function.
837
+ erfc: Complementary error function.
838
+ erfi: Imaginary error function.
839
+ erf2: Two-argument error function.
840
+ erfcinv: Inverse Complementary error function.
841
+ erf2inv: Inverse two-argument error function.
842
+
843
+ References
844
+ ==========
845
+
846
+ .. [1] https://en.wikipedia.org/wiki/Error_function#Inverse_functions
847
+ .. [2] https://functions.wolfram.com/GammaBetaErf/InverseErf/
848
+
849
+ """
850
+
851
+
852
+ def fdiff(self, argindex =1):
853
+ if argindex == 1:
854
+ return sqrt(pi)*exp(self.func(self.args[0])**2)*S.Half
855
+ else :
856
+ raise ArgumentIndexError(self, argindex)
857
+
858
+ def inverse(self, argindex=1):
859
+ """
860
+ Returns the inverse of this function.
861
+
862
+ """
863
+ return erf
864
+
865
+ @classmethod
866
+ def eval(cls, z):
867
+ if z is S.NaN:
868
+ return S.NaN
869
+ elif z is S.NegativeOne:
870
+ return S.NegativeInfinity
871
+ elif z.is_zero:
872
+ return S.Zero
873
+ elif z is S.One:
874
+ return S.Infinity
875
+
876
+ if isinstance(z, erf) and z.args[0].is_extended_real:
877
+ return z.args[0]
878
+
879
+ if z.is_zero:
880
+ return S.Zero
881
+
882
+ # Try to pull out factors of -1
883
+ nz = z.extract_multiplicatively(-1)
884
+ if nz is not None and (isinstance(nz, erf) and (nz.args[0]).is_extended_real):
885
+ return -nz.args[0]
886
+
887
+ def _eval_rewrite_as_erfcinv(self, z, **kwargs):
888
+ return erfcinv(1-z)
889
+
890
+ def _eval_is_zero(self):
891
+ return self.args[0].is_zero
892
+
893
+
894
+ class erfcinv (Function):
895
+ r"""
896
+ Inverse Complementary Error Function. The erfcinv function is defined as:
897
+
898
+ .. math ::
899
+ \mathrm{erfc}(x) = y \quad \Rightarrow \quad \mathrm{erfcinv}(y) = x
900
+
901
+ Examples
902
+ ========
903
+
904
+ >>> from sympy import erfcinv
905
+ >>> from sympy.abc import x
906
+
907
+ Several special values are known:
908
+
909
+ >>> erfcinv(1)
910
+ 0
911
+ >>> erfcinv(0)
912
+ oo
913
+
914
+ Differentiation with respect to $x$ is supported:
915
+
916
+ >>> from sympy import diff
917
+ >>> diff(erfcinv(x), x)
918
+ -sqrt(pi)*exp(erfcinv(x)**2)/2
919
+
920
+ See Also
921
+ ========
922
+
923
+ erf: Gaussian error function.
924
+ erfc: Complementary error function.
925
+ erfi: Imaginary error function.
926
+ erf2: Two-argument error function.
927
+ erfinv: Inverse error function.
928
+ erf2inv: Inverse two-argument error function.
929
+
930
+ References
931
+ ==========
932
+
933
+ .. [1] https://en.wikipedia.org/wiki/Error_function#Inverse_functions
934
+ .. [2] https://functions.wolfram.com/GammaBetaErf/InverseErfc/
935
+
936
+ """
937
+
938
+
939
+ def fdiff(self, argindex =1):
940
+ if argindex == 1:
941
+ return -sqrt(pi)*exp(self.func(self.args[0])**2)*S.Half
942
+ else:
943
+ raise ArgumentIndexError(self, argindex)
944
+
945
+ def inverse(self, argindex=1):
946
+ """
947
+ Returns the inverse of this function.
948
+
949
+ """
950
+ return erfc
951
+
952
+ @classmethod
953
+ def eval(cls, z):
954
+ if z is S.NaN:
955
+ return S.NaN
956
+ elif z.is_zero:
957
+ return S.Infinity
958
+ elif z is S.One:
959
+ return S.Zero
960
+ elif z == 2:
961
+ return S.NegativeInfinity
962
+
963
+ if z.is_zero:
964
+ return S.Infinity
965
+
966
+ def _eval_rewrite_as_erfinv(self, z, **kwargs):
967
+ return erfinv(1-z)
968
+
969
+ def _eval_is_zero(self):
970
+ return (self.args[0] - 1).is_zero
971
+
972
+ def _eval_is_infinite(self):
973
+ return self.args[0].is_zero
974
+
975
+
976
+ class erf2inv(Function):
977
+ r"""
978
+ Two-argument Inverse error function. The erf2inv function is defined as:
979
+
980
+ .. math ::
981
+ \mathrm{erf2}(x, w) = y \quad \Rightarrow \quad \mathrm{erf2inv}(x, y) = w
982
+
983
+ Examples
984
+ ========
985
+
986
+ >>> from sympy import erf2inv, oo
987
+ >>> from sympy.abc import x, y
988
+
989
+ Several special values are known:
990
+
991
+ >>> erf2inv(0, 0)
992
+ 0
993
+ >>> erf2inv(1, 0)
994
+ 1
995
+ >>> erf2inv(0, 1)
996
+ oo
997
+ >>> erf2inv(0, y)
998
+ erfinv(y)
999
+ >>> erf2inv(oo, y)
1000
+ erfcinv(-y)
1001
+
1002
+ Differentiation with respect to $x$ and $y$ is supported:
1003
+
1004
+ >>> from sympy import diff
1005
+ >>> diff(erf2inv(x, y), x)
1006
+ exp(-x**2 + erf2inv(x, y)**2)
1007
+ >>> diff(erf2inv(x, y), y)
1008
+ sqrt(pi)*exp(erf2inv(x, y)**2)/2
1009
+
1010
+ See Also
1011
+ ========
1012
+
1013
+ erf: Gaussian error function.
1014
+ erfc: Complementary error function.
1015
+ erfi: Imaginary error function.
1016
+ erf2: Two-argument error function.
1017
+ erfinv: Inverse error function.
1018
+ erfcinv: Inverse complementary error function.
1019
+
1020
+ References
1021
+ ==========
1022
+
1023
+ .. [1] https://functions.wolfram.com/GammaBetaErf/InverseErf2/
1024
+
1025
+ """
1026
+
1027
+
1028
+ def fdiff(self, argindex):
1029
+ x, y = self.args
1030
+ if argindex == 1:
1031
+ return exp(self.func(x,y)**2-x**2)
1032
+ elif argindex == 2:
1033
+ return sqrt(pi)*S.Half*exp(self.func(x,y)**2)
1034
+ else:
1035
+ raise ArgumentIndexError(self, argindex)
1036
+
1037
+ @classmethod
1038
+ def eval(cls, x, y):
1039
+ if x is S.NaN or y is S.NaN:
1040
+ return S.NaN
1041
+ elif x.is_zero and y.is_zero:
1042
+ return S.Zero
1043
+ elif x.is_zero and y is S.One:
1044
+ return S.Infinity
1045
+ elif x is S.One and y.is_zero:
1046
+ return S.One
1047
+ elif x.is_zero:
1048
+ return erfinv(y)
1049
+ elif x is S.Infinity:
1050
+ return erfcinv(-y)
1051
+ elif y.is_zero:
1052
+ return x
1053
+ elif y is S.Infinity:
1054
+ return erfinv(x)
1055
+
1056
+ if x.is_zero:
1057
+ if y.is_zero:
1058
+ return S.Zero
1059
+ else:
1060
+ return erfinv(y)
1061
+ if y.is_zero:
1062
+ return x
1063
+
1064
+ def _eval_is_zero(self):
1065
+ x, y = self.args
1066
+ if x.is_zero and y.is_zero:
1067
+ return True
1068
+
1069
+ ###############################################################################
1070
+ #################### EXPONENTIAL INTEGRALS ####################################
1071
+ ###############################################################################
1072
+
1073
+ class Ei(Function):
1074
+ r"""
1075
+ The classical exponential integral.
1076
+
1077
+ Explanation
1078
+ ===========
1079
+
1080
+ For use in SymPy, this function is defined as
1081
+
1082
+ .. math:: \operatorname{Ei}(x) = \sum_{n=1}^\infty \frac{x^n}{n\, n!}
1083
+ + \log(x) + \gamma,
1084
+
1085
+ where $\gamma$ is the Euler-Mascheroni constant.
1086
+
1087
+ If $x$ is a polar number, this defines an analytic function on the
1088
+ Riemann surface of the logarithm. Otherwise this defines an analytic
1089
+ function in the cut plane $\mathbb{C} \setminus (-\infty, 0]$.
1090
+
1091
+ **Background**
1092
+
1093
+ The name exponential integral comes from the following statement:
1094
+
1095
+ .. math:: \operatorname{Ei}(x) = \int_{-\infty}^x \frac{e^t}{t} \mathrm{d}t
1096
+
1097
+ If the integral is interpreted as a Cauchy principal value, this statement
1098
+ holds for $x > 0$ and $\operatorname{Ei}(x)$ as defined above.
1099
+
1100
+ Examples
1101
+ ========
1102
+
1103
+ >>> from sympy import Ei, polar_lift, exp_polar, I, pi
1104
+ >>> from sympy.abc import x
1105
+
1106
+ >>> Ei(-1)
1107
+ Ei(-1)
1108
+
1109
+ This yields a real value:
1110
+
1111
+ >>> Ei(-1).n(chop=True)
1112
+ -0.219383934395520
1113
+
1114
+ On the other hand the analytic continuation is not real:
1115
+
1116
+ >>> Ei(polar_lift(-1)).n(chop=True)
1117
+ -0.21938393439552 + 3.14159265358979*I
1118
+
1119
+ The exponential integral has a logarithmic branch point at the origin:
1120
+
1121
+ >>> Ei(x*exp_polar(2*I*pi))
1122
+ Ei(x) + 2*I*pi
1123
+
1124
+ Differentiation is supported:
1125
+
1126
+ >>> Ei(x).diff(x)
1127
+ exp(x)/x
1128
+
1129
+ The exponential integral is related to many other special functions.
1130
+ For example:
1131
+
1132
+ >>> from sympy import expint, Shi
1133
+ >>> Ei(x).rewrite(expint)
1134
+ -expint(1, x*exp_polar(I*pi)) - I*pi
1135
+ >>> Ei(x).rewrite(Shi)
1136
+ Chi(x) + Shi(x)
1137
+
1138
+ See Also
1139
+ ========
1140
+
1141
+ expint: Generalised exponential integral.
1142
+ E1: Special case of the generalised exponential integral.
1143
+ li: Logarithmic integral.
1144
+ Li: Offset logarithmic integral.
1145
+ Si: Sine integral.
1146
+ Ci: Cosine integral.
1147
+ Shi: Hyperbolic sine integral.
1148
+ Chi: Hyperbolic cosine integral.
1149
+ uppergamma: Upper incomplete gamma function.
1150
+
1151
+ References
1152
+ ==========
1153
+
1154
+ .. [1] https://dlmf.nist.gov/6.6
1155
+ .. [2] https://en.wikipedia.org/wiki/Exponential_integral
1156
+ .. [3] Abramowitz & Stegun, section 5: https://web.archive.org/web/20201128173312/http://people.math.sfu.ca/~cbm/aands/page_228.htm
1157
+
1158
+ """
1159
+
1160
+
1161
+ @classmethod
1162
+ def eval(cls, z):
1163
+ if z.is_zero:
1164
+ return S.NegativeInfinity
1165
+ elif z is S.Infinity:
1166
+ return S.Infinity
1167
+ elif z is S.NegativeInfinity:
1168
+ return S.Zero
1169
+
1170
+ if z.is_zero:
1171
+ return S.NegativeInfinity
1172
+
1173
+ nz, n = z.extract_branch_factor()
1174
+ if n:
1175
+ return Ei(nz) + 2*I*pi*n
1176
+
1177
+ def fdiff(self, argindex=1):
1178
+ arg = unpolarify(self.args[0])
1179
+ if argindex == 1:
1180
+ return exp(arg)/arg
1181
+ else:
1182
+ raise ArgumentIndexError(self, argindex)
1183
+
1184
+ def _eval_evalf(self, prec):
1185
+ if (self.args[0]/polar_lift(-1)).is_positive:
1186
+ return Function._eval_evalf(self, prec) + (I*pi)._eval_evalf(prec)
1187
+ return Function._eval_evalf(self, prec)
1188
+
1189
+ def _eval_rewrite_as_uppergamma(self, z, **kwargs):
1190
+ from sympy.functions.special.gamma_functions import uppergamma
1191
+ # XXX this does not currently work usefully because uppergamma
1192
+ # immediately turns into expint
1193
+ return -uppergamma(0, polar_lift(-1)*z) - I*pi
1194
+
1195
+ def _eval_rewrite_as_expint(self, z, **kwargs):
1196
+ return -expint(1, polar_lift(-1)*z) - I*pi
1197
+
1198
+ def _eval_rewrite_as_li(self, z, **kwargs):
1199
+ if isinstance(z, log):
1200
+ return li(z.args[0])
1201
+ # TODO:
1202
+ # Actually it only holds that:
1203
+ # Ei(z) = li(exp(z))
1204
+ # for -pi < imag(z) <= pi
1205
+ return li(exp(z))
1206
+
1207
+ def _eval_rewrite_as_Si(self, z, **kwargs):
1208
+ if z.is_negative:
1209
+ return Shi(z) + Chi(z) - I*pi
1210
+ else:
1211
+ return Shi(z) + Chi(z)
1212
+ _eval_rewrite_as_Ci = _eval_rewrite_as_Si
1213
+ _eval_rewrite_as_Chi = _eval_rewrite_as_Si
1214
+ _eval_rewrite_as_Shi = _eval_rewrite_as_Si
1215
+
1216
+ def _eval_rewrite_as_tractable(self, z, limitvar=None, **kwargs):
1217
+ return exp(z) * _eis(z)
1218
+
1219
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
1220
+ from sympy import re
1221
+ x0 = self.args[0].limit(x, 0)
1222
+ arg = self.args[0].as_leading_term(x, cdir=cdir)
1223
+ cdir = arg.dir(x, cdir)
1224
+ if x0.is_zero:
1225
+ c, e = arg.as_coeff_exponent(x)
1226
+ logx = log(x) if logx is None else logx
1227
+ return log(c) + e*logx + EulerGamma - (
1228
+ I*pi if re(cdir).is_negative else S.Zero)
1229
+ return super()._eval_as_leading_term(x, logx=logx, cdir=cdir)
1230
+
1231
+ def _eval_nseries(self, x, n, logx, cdir=0):
1232
+ x0 = self.args[0].limit(x, 0)
1233
+ if x0.is_zero:
1234
+ f = self._eval_rewrite_as_Si(*self.args)
1235
+ return f._eval_nseries(x, n, logx)
1236
+ return super()._eval_nseries(x, n, logx)
1237
+
1238
+ def _eval_aseries(self, n, args0, x, logx):
1239
+ from sympy.series.order import Order
1240
+ point = args0[0]
1241
+
1242
+ if point is S.Infinity:
1243
+ z = self.args[0]
1244
+ s = [factorial(k) / (z)**k for k in range(n)] + \
1245
+ [Order(1/z**n, x)]
1246
+ return (exp(z)/z) * Add(*s)
1247
+
1248
+ return super(Ei, self)._eval_aseries(n, args0, x, logx)
1249
+
1250
+
1251
+ class expint(Function):
1252
+ r"""
1253
+ Generalized exponential integral.
1254
+
1255
+ Explanation
1256
+ ===========
1257
+
1258
+ This function is defined as
1259
+
1260
+ .. math:: \operatorname{E}_\nu(z) = z^{\nu - 1} \Gamma(1 - \nu, z),
1261
+
1262
+ where $\Gamma(1 - \nu, z)$ is the upper incomplete gamma function
1263
+ (``uppergamma``).
1264
+
1265
+ Hence for $z$ with positive real part we have
1266
+
1267
+ .. math:: \operatorname{E}_\nu(z)
1268
+ = \int_1^\infty \frac{e^{-zt}}{t^\nu} \mathrm{d}t,
1269
+
1270
+ which explains the name.
1271
+
1272
+ The representation as an incomplete gamma function provides an analytic
1273
+ continuation for $\operatorname{E}_\nu(z)$. If $\nu$ is a
1274
+ non-positive integer, the exponential integral is thus an unbranched
1275
+ function of $z$, otherwise there is a branch point at the origin.
1276
+ Refer to the incomplete gamma function documentation for details of the
1277
+ branching behavior.
1278
+
1279
+ Examples
1280
+ ========
1281
+
1282
+ >>> from sympy import expint, S
1283
+ >>> from sympy.abc import nu, z
1284
+
1285
+ Differentiation is supported. Differentiation with respect to $z$ further
1286
+ explains the name: for integral orders, the exponential integral is an
1287
+ iterated integral of the exponential function.
1288
+
1289
+ >>> expint(nu, z).diff(z)
1290
+ -expint(nu - 1, z)
1291
+
1292
+ Differentiation with respect to $\nu$ has no classical expression:
1293
+
1294
+ >>> expint(nu, z).diff(nu)
1295
+ -z**(nu - 1)*meijerg(((), (1, 1)), ((0, 0, 1 - nu), ()), z)
1296
+
1297
+ At non-postive integer orders, the exponential integral reduces to the
1298
+ exponential function:
1299
+
1300
+ >>> expint(0, z)
1301
+ exp(-z)/z
1302
+ >>> expint(-1, z)
1303
+ exp(-z)/z + exp(-z)/z**2
1304
+
1305
+ At half-integers it reduces to error functions:
1306
+
1307
+ >>> expint(S(1)/2, z)
1308
+ sqrt(pi)*erfc(sqrt(z))/sqrt(z)
1309
+
1310
+ At positive integer orders it can be rewritten in terms of exponentials
1311
+ and ``expint(1, z)``. Use ``expand_func()`` to do this:
1312
+
1313
+ >>> from sympy import expand_func
1314
+ >>> expand_func(expint(5, z))
1315
+ z**4*expint(1, z)/24 + (-z**3 + z**2 - 2*z + 6)*exp(-z)/24
1316
+
1317
+ The generalised exponential integral is essentially equivalent to the
1318
+ incomplete gamma function:
1319
+
1320
+ >>> from sympy import uppergamma
1321
+ >>> expint(nu, z).rewrite(uppergamma)
1322
+ z**(nu - 1)*uppergamma(1 - nu, z)
1323
+
1324
+ As such it is branched at the origin:
1325
+
1326
+ >>> from sympy import exp_polar, pi, I
1327
+ >>> expint(4, z*exp_polar(2*pi*I))
1328
+ I*pi*z**3/3 + expint(4, z)
1329
+ >>> expint(nu, z*exp_polar(2*pi*I))
1330
+ z**(nu - 1)*(exp(2*I*pi*nu) - 1)*gamma(1 - nu) + expint(nu, z)
1331
+
1332
+ See Also
1333
+ ========
1334
+
1335
+ Ei: Another related function called exponential integral.
1336
+ E1: The classical case, returns expint(1, z).
1337
+ li: Logarithmic integral.
1338
+ Li: Offset logarithmic integral.
1339
+ Si: Sine integral.
1340
+ Ci: Cosine integral.
1341
+ Shi: Hyperbolic sine integral.
1342
+ Chi: Hyperbolic cosine integral.
1343
+ uppergamma
1344
+
1345
+ References
1346
+ ==========
1347
+
1348
+ .. [1] https://dlmf.nist.gov/8.19
1349
+ .. [2] https://functions.wolfram.com/GammaBetaErf/ExpIntegralE/
1350
+ .. [3] https://en.wikipedia.org/wiki/Exponential_integral
1351
+
1352
+ """
1353
+
1354
+
1355
+ @classmethod
1356
+ def eval(cls, nu, z):
1357
+ from sympy.functions.special.gamma_functions import (gamma, uppergamma)
1358
+ nu2 = unpolarify(nu)
1359
+ if nu != nu2:
1360
+ return expint(nu2, z)
1361
+ if nu.is_Integer and nu <= 0 or (not nu.is_Integer and (2*nu).is_Integer):
1362
+ return unpolarify(expand_mul(z**(nu - 1)*uppergamma(1 - nu, z)))
1363
+
1364
+ # Extract branching information. This can be deduced from what is
1365
+ # explained in lowergamma.eval().
1366
+ z, n = z.extract_branch_factor()
1367
+ if n is S.Zero:
1368
+ return
1369
+ if nu.is_integer:
1370
+ if not nu > 0:
1371
+ return
1372
+ return expint(nu, z) \
1373
+ - 2*pi*I*n*S.NegativeOne**(nu - 1)/factorial(nu - 1)*unpolarify(z)**(nu - 1)
1374
+ else:
1375
+ return (exp(2*I*pi*nu*n) - 1)*z**(nu - 1)*gamma(1 - nu) + expint(nu, z)
1376
+
1377
+ def fdiff(self, argindex):
1378
+ nu, z = self.args
1379
+ if argindex == 1:
1380
+ return -z**(nu - 1)*meijerg([], [1, 1], [0, 0, 1 - nu], [], z)
1381
+ elif argindex == 2:
1382
+ return -expint(nu - 1, z)
1383
+ else:
1384
+ raise ArgumentIndexError(self, argindex)
1385
+
1386
+ def _eval_rewrite_as_uppergamma(self, nu, z, **kwargs):
1387
+ from sympy.functions.special.gamma_functions import uppergamma
1388
+ return z**(nu - 1)*uppergamma(1 - nu, z)
1389
+
1390
+ def _eval_rewrite_as_Ei(self, nu, z, **kwargs):
1391
+ if nu == 1:
1392
+ return -Ei(z*exp_polar(-I*pi)) - I*pi
1393
+ elif nu.is_Integer and nu > 1:
1394
+ # DLMF, 8.19.7
1395
+ x = -unpolarify(z)
1396
+ return x**(nu - 1)/factorial(nu - 1)*E1(z).rewrite(Ei) + \
1397
+ exp(x)/factorial(nu - 1) * \
1398
+ Add(*[factorial(nu - k - 2)*x**k for k in range(nu - 1)])
1399
+ else:
1400
+ return self
1401
+
1402
+ def _eval_expand_func(self, **hints):
1403
+ return self.rewrite(Ei).rewrite(expint, **hints)
1404
+
1405
+ def _eval_rewrite_as_Si(self, nu, z, **kwargs):
1406
+ if nu != 1:
1407
+ return self
1408
+ return Shi(z) - Chi(z)
1409
+ _eval_rewrite_as_Ci = _eval_rewrite_as_Si
1410
+ _eval_rewrite_as_Chi = _eval_rewrite_as_Si
1411
+ _eval_rewrite_as_Shi = _eval_rewrite_as_Si
1412
+
1413
+ def _eval_nseries(self, x, n, logx, cdir=0):
1414
+ if not self.args[0].has(x):
1415
+ nu = self.args[0]
1416
+ if nu == 1:
1417
+ f = self._eval_rewrite_as_Si(*self.args)
1418
+ return f._eval_nseries(x, n, logx)
1419
+ elif nu.is_Integer and nu > 1:
1420
+ f = self._eval_rewrite_as_Ei(*self.args)
1421
+ return f._eval_nseries(x, n, logx)
1422
+ return super()._eval_nseries(x, n, logx)
1423
+
1424
+ def _eval_aseries(self, n, args0, x, logx):
1425
+ from sympy.series.order import Order
1426
+ point = args0[1]
1427
+ nu = self.args[0]
1428
+
1429
+ if point is S.Infinity:
1430
+ z = self.args[1]
1431
+ s = [S.NegativeOne**k * RisingFactorial(nu, k) / z**k for k in range(n)] + [Order(1/z**n, x)]
1432
+ return (exp(-z)/z) * Add(*s)
1433
+
1434
+ return super(expint, self)._eval_aseries(n, args0, x, logx)
1435
+
1436
+
1437
+ def E1(z):
1438
+ """
1439
+ Classical case of the generalized exponential integral.
1440
+
1441
+ Explanation
1442
+ ===========
1443
+
1444
+ This is equivalent to ``expint(1, z)``.
1445
+
1446
+ Examples
1447
+ ========
1448
+
1449
+ >>> from sympy import E1
1450
+ >>> E1(0)
1451
+ expint(1, 0)
1452
+
1453
+ >>> E1(5)
1454
+ expint(1, 5)
1455
+
1456
+ See Also
1457
+ ========
1458
+
1459
+ Ei: Exponential integral.
1460
+ expint: Generalised exponential integral.
1461
+ li: Logarithmic integral.
1462
+ Li: Offset logarithmic integral.
1463
+ Si: Sine integral.
1464
+ Ci: Cosine integral.
1465
+ Shi: Hyperbolic sine integral.
1466
+ Chi: Hyperbolic cosine integral.
1467
+
1468
+ """
1469
+ return expint(1, z)
1470
+
1471
+
1472
+ class li(Function):
1473
+ r"""
1474
+ The classical logarithmic integral.
1475
+
1476
+ Explanation
1477
+ ===========
1478
+
1479
+ For use in SymPy, this function is defined as
1480
+
1481
+ .. math:: \operatorname{li}(x) = \int_0^x \frac{1}{\log(t)} \mathrm{d}t \,.
1482
+
1483
+ Examples
1484
+ ========
1485
+
1486
+ >>> from sympy import I, oo, li
1487
+ >>> from sympy.abc import z
1488
+
1489
+ Several special values are known:
1490
+
1491
+ >>> li(0)
1492
+ 0
1493
+ >>> li(1)
1494
+ -oo
1495
+ >>> li(oo)
1496
+ oo
1497
+
1498
+ Differentiation with respect to $z$ is supported:
1499
+
1500
+ >>> from sympy import diff
1501
+ >>> diff(li(z), z)
1502
+ 1/log(z)
1503
+
1504
+ Defining the ``li`` function via an integral:
1505
+ >>> from sympy import integrate
1506
+ >>> integrate(li(z))
1507
+ z*li(z) - Ei(2*log(z))
1508
+
1509
+ >>> integrate(li(z),z)
1510
+ z*li(z) - Ei(2*log(z))
1511
+
1512
+
1513
+ The logarithmic integral can also be defined in terms of ``Ei``:
1514
+
1515
+ >>> from sympy import Ei
1516
+ >>> li(z).rewrite(Ei)
1517
+ Ei(log(z))
1518
+ >>> diff(li(z).rewrite(Ei), z)
1519
+ 1/log(z)
1520
+
1521
+ We can numerically evaluate the logarithmic integral to arbitrary precision
1522
+ on the whole complex plane (except the singular points):
1523
+
1524
+ >>> li(2).evalf(30)
1525
+ 1.04516378011749278484458888919
1526
+
1527
+ >>> li(2*I).evalf(30)
1528
+ 1.0652795784357498247001125598 + 3.08346052231061726610939702133*I
1529
+
1530
+ We can even compute Soldner's constant by the help of mpmath:
1531
+
1532
+ >>> from mpmath import findroot
1533
+ >>> findroot(li, 2)
1534
+ 1.45136923488338
1535
+
1536
+ Further transformations include rewriting ``li`` in terms of
1537
+ the trigonometric integrals ``Si``, ``Ci``, ``Shi`` and ``Chi``:
1538
+
1539
+ >>> from sympy import Si, Ci, Shi, Chi
1540
+ >>> li(z).rewrite(Si)
1541
+ -log(I*log(z)) - log(1/log(z))/2 + log(log(z))/2 + Ci(I*log(z)) + Shi(log(z))
1542
+ >>> li(z).rewrite(Ci)
1543
+ -log(I*log(z)) - log(1/log(z))/2 + log(log(z))/2 + Ci(I*log(z)) + Shi(log(z))
1544
+ >>> li(z).rewrite(Shi)
1545
+ -log(1/log(z))/2 + log(log(z))/2 + Chi(log(z)) - Shi(log(z))
1546
+ >>> li(z).rewrite(Chi)
1547
+ -log(1/log(z))/2 + log(log(z))/2 + Chi(log(z)) - Shi(log(z))
1548
+
1549
+ See Also
1550
+ ========
1551
+
1552
+ Li: Offset logarithmic integral.
1553
+ Ei: Exponential integral.
1554
+ expint: Generalised exponential integral.
1555
+ E1: Special case of the generalised exponential integral.
1556
+ Si: Sine integral.
1557
+ Ci: Cosine integral.
1558
+ Shi: Hyperbolic sine integral.
1559
+ Chi: Hyperbolic cosine integral.
1560
+
1561
+ References
1562
+ ==========
1563
+
1564
+ .. [1] https://en.wikipedia.org/wiki/Logarithmic_integral
1565
+ .. [2] https://mathworld.wolfram.com/LogarithmicIntegral.html
1566
+ .. [3] https://dlmf.nist.gov/6
1567
+ .. [4] https://mathworld.wolfram.com/SoldnersConstant.html
1568
+
1569
+ """
1570
+
1571
+
1572
+ @classmethod
1573
+ def eval(cls, z):
1574
+ if z.is_zero:
1575
+ return S.Zero
1576
+ elif z is S.One:
1577
+ return S.NegativeInfinity
1578
+ elif z is S.Infinity:
1579
+ return S.Infinity
1580
+ if z.is_zero:
1581
+ return S.Zero
1582
+
1583
+ def fdiff(self, argindex=1):
1584
+ arg = self.args[0]
1585
+ if argindex == 1:
1586
+ return S.One / log(arg)
1587
+ else:
1588
+ raise ArgumentIndexError(self, argindex)
1589
+
1590
+ def _eval_conjugate(self):
1591
+ z = self.args[0]
1592
+ # Exclude values on the branch cut (-oo, 0)
1593
+ if not z.is_extended_negative:
1594
+ return self.func(z.conjugate())
1595
+
1596
+ def _eval_rewrite_as_Li(self, z, **kwargs):
1597
+ return Li(z) + li(2)
1598
+
1599
+ def _eval_rewrite_as_Ei(self, z, **kwargs):
1600
+ return Ei(log(z))
1601
+
1602
+ def _eval_rewrite_as_uppergamma(self, z, **kwargs):
1603
+ from sympy.functions.special.gamma_functions import uppergamma
1604
+ return (-uppergamma(0, -log(z)) +
1605
+ S.Half*(log(log(z)) - log(S.One/log(z))) - log(-log(z)))
1606
+
1607
+ def _eval_rewrite_as_Si(self, z, **kwargs):
1608
+ return (Ci(I*log(z)) - I*Si(I*log(z)) -
1609
+ S.Half*(log(S.One/log(z)) - log(log(z))) - log(I*log(z)))
1610
+
1611
+ _eval_rewrite_as_Ci = _eval_rewrite_as_Si
1612
+
1613
+ def _eval_rewrite_as_Shi(self, z, **kwargs):
1614
+ return (Chi(log(z)) - Shi(log(z)) - S.Half*(log(S.One/log(z)) - log(log(z))))
1615
+
1616
+ _eval_rewrite_as_Chi = _eval_rewrite_as_Shi
1617
+
1618
+ def _eval_rewrite_as_hyper(self, z, **kwargs):
1619
+ return (log(z)*hyper((1, 1), (2, 2), log(z)) +
1620
+ S.Half*(log(log(z)) - log(S.One/log(z))) + EulerGamma)
1621
+
1622
+ def _eval_rewrite_as_meijerg(self, z, **kwargs):
1623
+ return (-log(-log(z)) - S.Half*(log(S.One/log(z)) - log(log(z)))
1624
+ - meijerg(((), (1,)), ((0, 0), ()), -log(z)))
1625
+
1626
+ def _eval_rewrite_as_tractable(self, z, limitvar=None, **kwargs):
1627
+ return z * _eis(log(z))
1628
+
1629
+ def _eval_nseries(self, x, n, logx, cdir=0):
1630
+ z = self.args[0]
1631
+ s = [(log(z))**k / (factorial(k) * k) for k in range(1, n)]
1632
+ return EulerGamma + log(log(z)) + Add(*s)
1633
+
1634
+ def _eval_is_zero(self):
1635
+ z = self.args[0]
1636
+ if z.is_zero:
1637
+ return True
1638
+
1639
+ class Li(Function):
1640
+ r"""
1641
+ The offset logarithmic integral.
1642
+
1643
+ Explanation
1644
+ ===========
1645
+
1646
+ For use in SymPy, this function is defined as
1647
+
1648
+ .. math:: \operatorname{Li}(x) = \operatorname{li}(x) - \operatorname{li}(2)
1649
+
1650
+ Examples
1651
+ ========
1652
+
1653
+ >>> from sympy import Li
1654
+ >>> from sympy.abc import z
1655
+
1656
+ The following special value is known:
1657
+
1658
+ >>> Li(2)
1659
+ 0
1660
+
1661
+ Differentiation with respect to $z$ is supported:
1662
+
1663
+ >>> from sympy import diff
1664
+ >>> diff(Li(z), z)
1665
+ 1/log(z)
1666
+
1667
+ The shifted logarithmic integral can be written in terms of $li(z)$:
1668
+
1669
+ >>> from sympy import li
1670
+ >>> Li(z).rewrite(li)
1671
+ li(z) - li(2)
1672
+
1673
+ We can numerically evaluate the logarithmic integral to arbitrary precision
1674
+ on the whole complex plane (except the singular points):
1675
+
1676
+ >>> Li(2).evalf(30)
1677
+ 0
1678
+
1679
+ >>> Li(4).evalf(30)
1680
+ 1.92242131492155809316615998938
1681
+
1682
+ See Also
1683
+ ========
1684
+
1685
+ li: Logarithmic integral.
1686
+ Ei: Exponential integral.
1687
+ expint: Generalised exponential integral.
1688
+ E1: Special case of the generalised exponential integral.
1689
+ Si: Sine integral.
1690
+ Ci: Cosine integral.
1691
+ Shi: Hyperbolic sine integral.
1692
+ Chi: Hyperbolic cosine integral.
1693
+
1694
+ References
1695
+ ==========
1696
+
1697
+ .. [1] https://en.wikipedia.org/wiki/Logarithmic_integral
1698
+ .. [2] https://mathworld.wolfram.com/LogarithmicIntegral.html
1699
+ .. [3] https://dlmf.nist.gov/6
1700
+
1701
+ """
1702
+
1703
+
1704
+ @classmethod
1705
+ def eval(cls, z):
1706
+ if z is S.Infinity:
1707
+ return S.Infinity
1708
+ elif z == S(2):
1709
+ return S.Zero
1710
+
1711
+ def fdiff(self, argindex=1):
1712
+ arg = self.args[0]
1713
+ if argindex == 1:
1714
+ return S.One / log(arg)
1715
+ else:
1716
+ raise ArgumentIndexError(self, argindex)
1717
+
1718
+ def _eval_evalf(self, prec):
1719
+ return self.rewrite(li).evalf(prec)
1720
+
1721
+ def _eval_rewrite_as_li(self, z, **kwargs):
1722
+ return li(z) - li(2)
1723
+
1724
+ def _eval_rewrite_as_tractable(self, z, limitvar=None, **kwargs):
1725
+ return self.rewrite(li).rewrite("tractable", deep=True)
1726
+
1727
+ def _eval_nseries(self, x, n, logx, cdir=0):
1728
+ f = self._eval_rewrite_as_li(*self.args)
1729
+ return f._eval_nseries(x, n, logx)
1730
+
1731
+ ###############################################################################
1732
+ #################### TRIGONOMETRIC INTEGRALS ##################################
1733
+ ###############################################################################
1734
+
1735
+ class TrigonometricIntegral(Function):
1736
+ """ Base class for trigonometric integrals. """
1737
+
1738
+
1739
+ @classmethod
1740
+ def eval(cls, z):
1741
+ if z is S.Zero:
1742
+ return cls._atzero
1743
+ elif z is S.Infinity:
1744
+ return cls._atinf()
1745
+ elif z is S.NegativeInfinity:
1746
+ return cls._atneginf()
1747
+
1748
+ if z.is_zero:
1749
+ return cls._atzero
1750
+
1751
+ nz = z.extract_multiplicatively(polar_lift(I))
1752
+ if nz is None and cls._trigfunc(0) == 0:
1753
+ nz = z.extract_multiplicatively(I)
1754
+ if nz is not None:
1755
+ return cls._Ifactor(nz, 1)
1756
+ nz = z.extract_multiplicatively(polar_lift(-I))
1757
+ if nz is not None:
1758
+ return cls._Ifactor(nz, -1)
1759
+
1760
+ nz = z.extract_multiplicatively(polar_lift(-1))
1761
+ if nz is None and cls._trigfunc(0) == 0:
1762
+ nz = z.extract_multiplicatively(-1)
1763
+ if nz is not None:
1764
+ return cls._minusfactor(nz)
1765
+
1766
+ nz, n = z.extract_branch_factor()
1767
+ if n == 0 and nz == z:
1768
+ return
1769
+ return 2*pi*I*n*cls._trigfunc(0) + cls(nz)
1770
+
1771
+ def fdiff(self, argindex=1):
1772
+ arg = unpolarify(self.args[0])
1773
+ if argindex == 1:
1774
+ return self._trigfunc(arg)/arg
1775
+ else:
1776
+ raise ArgumentIndexError(self, argindex)
1777
+
1778
+ def _eval_rewrite_as_Ei(self, z, **kwargs):
1779
+ return self._eval_rewrite_as_expint(z).rewrite(Ei)
1780
+
1781
+ def _eval_rewrite_as_uppergamma(self, z, **kwargs):
1782
+ from sympy.functions.special.gamma_functions import uppergamma
1783
+ return self._eval_rewrite_as_expint(z).rewrite(uppergamma)
1784
+
1785
+ def _eval_nseries(self, x, n, logx, cdir=0):
1786
+ # NOTE this is fairly inefficient
1787
+ n += 1
1788
+ if self.args[0].subs(x, 0) != 0:
1789
+ return super()._eval_nseries(x, n, logx)
1790
+ baseseries = self._trigfunc(x)._eval_nseries(x, n, logx)
1791
+ if self._trigfunc(0) != 0:
1792
+ baseseries -= 1
1793
+ baseseries = baseseries.replace(Pow, lambda t, n: t**n/n, simultaneous=False)
1794
+ if self._trigfunc(0) != 0:
1795
+ baseseries += EulerGamma + log(x)
1796
+ return baseseries.subs(x, self.args[0])._eval_nseries(x, n, logx)
1797
+
1798
+
1799
+ class Si(TrigonometricIntegral):
1800
+ r"""
1801
+ Sine integral.
1802
+
1803
+ Explanation
1804
+ ===========
1805
+
1806
+ This function is defined by
1807
+
1808
+ .. math:: \operatorname{Si}(z) = \int_0^z \frac{\sin{t}}{t} \mathrm{d}t.
1809
+
1810
+ It is an entire function.
1811
+
1812
+ Examples
1813
+ ========
1814
+
1815
+ >>> from sympy import Si
1816
+ >>> from sympy.abc import z
1817
+
1818
+ The sine integral is an antiderivative of $sin(z)/z$:
1819
+
1820
+ >>> Si(z).diff(z)
1821
+ sin(z)/z
1822
+
1823
+ It is unbranched:
1824
+
1825
+ >>> from sympy import exp_polar, I, pi
1826
+ >>> Si(z*exp_polar(2*I*pi))
1827
+ Si(z)
1828
+
1829
+ Sine integral behaves much like ordinary sine under multiplication by ``I``:
1830
+
1831
+ >>> Si(I*z)
1832
+ I*Shi(z)
1833
+ >>> Si(-z)
1834
+ -Si(z)
1835
+
1836
+ It can also be expressed in terms of exponential integrals, but beware
1837
+ that the latter is branched:
1838
+
1839
+ >>> from sympy import expint
1840
+ >>> Si(z).rewrite(expint)
1841
+ -I*(-expint(1, z*exp_polar(-I*pi/2))/2 +
1842
+ expint(1, z*exp_polar(I*pi/2))/2) + pi/2
1843
+
1844
+ It can be rewritten in the form of sinc function (by definition):
1845
+
1846
+ >>> from sympy import sinc
1847
+ >>> Si(z).rewrite(sinc)
1848
+ Integral(sinc(t), (t, 0, z))
1849
+
1850
+ See Also
1851
+ ========
1852
+
1853
+ Ci: Cosine integral.
1854
+ Shi: Hyperbolic sine integral.
1855
+ Chi: Hyperbolic cosine integral.
1856
+ Ei: Exponential integral.
1857
+ expint: Generalised exponential integral.
1858
+ sinc: unnormalized sinc function
1859
+ E1: Special case of the generalised exponential integral.
1860
+ li: Logarithmic integral.
1861
+ Li: Offset logarithmic integral.
1862
+
1863
+ References
1864
+ ==========
1865
+
1866
+ .. [1] https://en.wikipedia.org/wiki/Trigonometric_integral
1867
+
1868
+ """
1869
+
1870
+ _trigfunc = sin
1871
+ _atzero = S.Zero
1872
+
1873
+ @classmethod
1874
+ def _atinf(cls):
1875
+ return pi*S.Half
1876
+
1877
+ @classmethod
1878
+ def _atneginf(cls):
1879
+ return -pi*S.Half
1880
+
1881
+ @classmethod
1882
+ def _minusfactor(cls, z):
1883
+ return -Si(z)
1884
+
1885
+ @classmethod
1886
+ def _Ifactor(cls, z, sign):
1887
+ return I*Shi(z)*sign
1888
+
1889
+ def _eval_rewrite_as_expint(self, z, **kwargs):
1890
+ # XXX should we polarify z?
1891
+ return pi/2 + (E1(polar_lift(I)*z) - E1(polar_lift(-I)*z))/2/I
1892
+
1893
+ def _eval_rewrite_as_sinc(self, z, **kwargs):
1894
+ from sympy.integrals.integrals import Integral
1895
+ t = Symbol('t', Dummy=True)
1896
+ return Integral(sinc(t), (t, 0, z))
1897
+
1898
+ def _eval_aseries(self, n, args0, x, logx):
1899
+ from sympy.series.order import Order
1900
+ point = args0[0]
1901
+
1902
+ # Expansion at oo
1903
+ if point is S.Infinity:
1904
+ z = self.args[0]
1905
+ p = [S.NegativeOne**k * factorial(2*k) / z**(2*k)
1906
+ for k in range(int((n - 1)/2))] + [Order(1/z**n, x)]
1907
+ q = [S.NegativeOne**k * factorial(2*k + 1) / z**(2*k + 1)
1908
+ for k in range(int(n/2) - 1)] + [Order(1/z**n, x)]
1909
+ return pi/2 - (cos(z)/z)*Add(*p) - (sin(z)/z)*Add(*q)
1910
+
1911
+ # All other points are not handled
1912
+ return super(Si, self)._eval_aseries(n, args0, x, logx)
1913
+
1914
+ def _eval_is_zero(self):
1915
+ z = self.args[0]
1916
+ if z.is_zero:
1917
+ return True
1918
+
1919
+
1920
+ class Ci(TrigonometricIntegral):
1921
+ r"""
1922
+ Cosine integral.
1923
+
1924
+ Explanation
1925
+ ===========
1926
+
1927
+ This function is defined for positive $x$ by
1928
+
1929
+ .. math:: \operatorname{Ci}(x) = \gamma + \log{x}
1930
+ + \int_0^x \frac{\cos{t} - 1}{t} \mathrm{d}t
1931
+ = -\int_x^\infty \frac{\cos{t}}{t} \mathrm{d}t,
1932
+
1933
+ where $\gamma$ is the Euler-Mascheroni constant.
1934
+
1935
+ We have
1936
+
1937
+ .. math:: \operatorname{Ci}(z) =
1938
+ -\frac{\operatorname{E}_1\left(e^{i\pi/2} z\right)
1939
+ + \operatorname{E}_1\left(e^{-i \pi/2} z\right)}{2}
1940
+
1941
+ which holds for all polar $z$ and thus provides an analytic
1942
+ continuation to the Riemann surface of the logarithm.
1943
+
1944
+ The formula also holds as stated
1945
+ for $z \in \mathbb{C}$ with $\Re(z) > 0$.
1946
+ By lifting to the principal branch, we obtain an analytic function on the
1947
+ cut complex plane.
1948
+
1949
+ Examples
1950
+ ========
1951
+
1952
+ >>> from sympy import Ci
1953
+ >>> from sympy.abc import z
1954
+
1955
+ The cosine integral is a primitive of $\cos(z)/z$:
1956
+
1957
+ >>> Ci(z).diff(z)
1958
+ cos(z)/z
1959
+
1960
+ It has a logarithmic branch point at the origin:
1961
+
1962
+ >>> from sympy import exp_polar, I, pi
1963
+ >>> Ci(z*exp_polar(2*I*pi))
1964
+ Ci(z) + 2*I*pi
1965
+
1966
+ The cosine integral behaves somewhat like ordinary $\cos$ under
1967
+ multiplication by $i$:
1968
+
1969
+ >>> from sympy import polar_lift
1970
+ >>> Ci(polar_lift(I)*z)
1971
+ Chi(z) + I*pi/2
1972
+ >>> Ci(polar_lift(-1)*z)
1973
+ Ci(z) + I*pi
1974
+
1975
+ It can also be expressed in terms of exponential integrals:
1976
+
1977
+ >>> from sympy import expint
1978
+ >>> Ci(z).rewrite(expint)
1979
+ -expint(1, z*exp_polar(-I*pi/2))/2 - expint(1, z*exp_polar(I*pi/2))/2
1980
+
1981
+ See Also
1982
+ ========
1983
+
1984
+ Si: Sine integral.
1985
+ Shi: Hyperbolic sine integral.
1986
+ Chi: Hyperbolic cosine integral.
1987
+ Ei: Exponential integral.
1988
+ expint: Generalised exponential integral.
1989
+ E1: Special case of the generalised exponential integral.
1990
+ li: Logarithmic integral.
1991
+ Li: Offset logarithmic integral.
1992
+
1993
+ References
1994
+ ==========
1995
+
1996
+ .. [1] https://en.wikipedia.org/wiki/Trigonometric_integral
1997
+
1998
+ """
1999
+
2000
+ _trigfunc = cos
2001
+ _atzero = S.ComplexInfinity
2002
+
2003
+ @classmethod
2004
+ def _atinf(cls):
2005
+ return S.Zero
2006
+
2007
+ @classmethod
2008
+ def _atneginf(cls):
2009
+ return I*pi
2010
+
2011
+ @classmethod
2012
+ def _minusfactor(cls, z):
2013
+ return Ci(z) + I*pi
2014
+
2015
+ @classmethod
2016
+ def _Ifactor(cls, z, sign):
2017
+ return Chi(z) + I*pi/2*sign
2018
+
2019
+ def _eval_rewrite_as_expint(self, z, **kwargs):
2020
+ return -(E1(polar_lift(I)*z) + E1(polar_lift(-I)*z))/2
2021
+
2022
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
2023
+ arg = self.args[0].as_leading_term(x, logx=logx, cdir=cdir)
2024
+ arg0 = arg.subs(x, 0)
2025
+
2026
+ if arg0 is S.NaN:
2027
+ arg0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
2028
+ if arg0.is_zero:
2029
+ c, e = arg.as_coeff_exponent(x)
2030
+ logx = log(x) if logx is None else logx
2031
+ return log(c) + e*logx + EulerGamma
2032
+ elif arg0.is_finite:
2033
+ return self.func(arg0)
2034
+ else:
2035
+ return self
2036
+
2037
+ def _eval_aseries(self, n, args0, x, logx):
2038
+ from sympy.series.order import Order
2039
+ point = args0[0]
2040
+
2041
+ # Expansion at oo
2042
+ if point is S.Infinity:
2043
+ z = self.args[0]
2044
+ p = [S.NegativeOne**k * factorial(2*k) / z**(2*k)
2045
+ for k in range(int((n - 1)/2))] + [Order(1/z**n, x)]
2046
+ q = [S.NegativeOne**k * factorial(2*k + 1) / z**(2*k + 1)
2047
+ for k in range(int(n/2) - 1)] + [Order(1/z**n, x)]
2048
+ return (sin(z)/z)*Add(*p) - (cos(z)/z)*Add(*q)
2049
+
2050
+ # All other points are not handled
2051
+ return super(Ci, self)._eval_aseries(n, args0, x, logx)
2052
+
2053
+
2054
+ class Shi(TrigonometricIntegral):
2055
+ r"""
2056
+ Sinh integral.
2057
+
2058
+ Explanation
2059
+ ===========
2060
+
2061
+ This function is defined by
2062
+
2063
+ .. math:: \operatorname{Shi}(z) = \int_0^z \frac{\sinh{t}}{t} \mathrm{d}t.
2064
+
2065
+ It is an entire function.
2066
+
2067
+ Examples
2068
+ ========
2069
+
2070
+ >>> from sympy import Shi
2071
+ >>> from sympy.abc import z
2072
+
2073
+ The Sinh integral is a primitive of $\sinh(z)/z$:
2074
+
2075
+ >>> Shi(z).diff(z)
2076
+ sinh(z)/z
2077
+
2078
+ It is unbranched:
2079
+
2080
+ >>> from sympy import exp_polar, I, pi
2081
+ >>> Shi(z*exp_polar(2*I*pi))
2082
+ Shi(z)
2083
+
2084
+ The $\sinh$ integral behaves much like ordinary $\sinh$ under
2085
+ multiplication by $i$:
2086
+
2087
+ >>> Shi(I*z)
2088
+ I*Si(z)
2089
+ >>> Shi(-z)
2090
+ -Shi(z)
2091
+
2092
+ It can also be expressed in terms of exponential integrals, but beware
2093
+ that the latter is branched:
2094
+
2095
+ >>> from sympy import expint
2096
+ >>> Shi(z).rewrite(expint)
2097
+ expint(1, z)/2 - expint(1, z*exp_polar(I*pi))/2 - I*pi/2
2098
+
2099
+ See Also
2100
+ ========
2101
+
2102
+ Si: Sine integral.
2103
+ Ci: Cosine integral.
2104
+ Chi: Hyperbolic cosine integral.
2105
+ Ei: Exponential integral.
2106
+ expint: Generalised exponential integral.
2107
+ E1: Special case of the generalised exponential integral.
2108
+ li: Logarithmic integral.
2109
+ Li: Offset logarithmic integral.
2110
+
2111
+ References
2112
+ ==========
2113
+
2114
+ .. [1] https://en.wikipedia.org/wiki/Trigonometric_integral
2115
+
2116
+ """
2117
+
2118
+ _trigfunc = sinh
2119
+ _atzero = S.Zero
2120
+
2121
+ @classmethod
2122
+ def _atinf(cls):
2123
+ return S.Infinity
2124
+
2125
+ @classmethod
2126
+ def _atneginf(cls):
2127
+ return S.NegativeInfinity
2128
+
2129
+ @classmethod
2130
+ def _minusfactor(cls, z):
2131
+ return -Shi(z)
2132
+
2133
+ @classmethod
2134
+ def _Ifactor(cls, z, sign):
2135
+ return I*Si(z)*sign
2136
+
2137
+ def _eval_rewrite_as_expint(self, z, **kwargs):
2138
+ # XXX should we polarify z?
2139
+ return (E1(z) - E1(exp_polar(I*pi)*z))/2 - I*pi/2
2140
+
2141
+ def _eval_is_zero(self):
2142
+ z = self.args[0]
2143
+ if z.is_zero:
2144
+ return True
2145
+
2146
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
2147
+ arg = self.args[0].as_leading_term(x)
2148
+ arg0 = arg.subs(x, 0)
2149
+
2150
+ if arg0 is S.NaN:
2151
+ arg0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
2152
+ if arg0.is_zero:
2153
+ return arg
2154
+ elif not arg0.is_infinite:
2155
+ return self.func(arg0)
2156
+ else:
2157
+ return self
2158
+
2159
+
2160
+ class Chi(TrigonometricIntegral):
2161
+ r"""
2162
+ Cosh integral.
2163
+
2164
+ Explanation
2165
+ ===========
2166
+
2167
+ This function is defined for positive $x$ by
2168
+
2169
+ .. math:: \operatorname{Chi}(x) = \gamma + \log{x}
2170
+ + \int_0^x \frac{\cosh{t} - 1}{t} \mathrm{d}t,
2171
+
2172
+ where $\gamma$ is the Euler-Mascheroni constant.
2173
+
2174
+ We have
2175
+
2176
+ .. math:: \operatorname{Chi}(z) = \operatorname{Ci}\left(e^{i \pi/2}z\right)
2177
+ - i\frac{\pi}{2},
2178
+
2179
+ which holds for all polar $z$ and thus provides an analytic
2180
+ continuation to the Riemann surface of the logarithm.
2181
+ By lifting to the principal branch we obtain an analytic function on the
2182
+ cut complex plane.
2183
+
2184
+ Examples
2185
+ ========
2186
+
2187
+ >>> from sympy import Chi
2188
+ >>> from sympy.abc import z
2189
+
2190
+ The $\cosh$ integral is a primitive of $\cosh(z)/z$:
2191
+
2192
+ >>> Chi(z).diff(z)
2193
+ cosh(z)/z
2194
+
2195
+ It has a logarithmic branch point at the origin:
2196
+
2197
+ >>> from sympy import exp_polar, I, pi
2198
+ >>> Chi(z*exp_polar(2*I*pi))
2199
+ Chi(z) + 2*I*pi
2200
+
2201
+ The $\cosh$ integral behaves somewhat like ordinary $\cosh$ under
2202
+ multiplication by $i$:
2203
+
2204
+ >>> from sympy import polar_lift
2205
+ >>> Chi(polar_lift(I)*z)
2206
+ Ci(z) + I*pi/2
2207
+ >>> Chi(polar_lift(-1)*z)
2208
+ Chi(z) + I*pi
2209
+
2210
+ It can also be expressed in terms of exponential integrals:
2211
+
2212
+ >>> from sympy import expint
2213
+ >>> Chi(z).rewrite(expint)
2214
+ -expint(1, z)/2 - expint(1, z*exp_polar(I*pi))/2 - I*pi/2
2215
+
2216
+ See Also
2217
+ ========
2218
+
2219
+ Si: Sine integral.
2220
+ Ci: Cosine integral.
2221
+ Shi: Hyperbolic sine integral.
2222
+ Ei: Exponential integral.
2223
+ expint: Generalised exponential integral.
2224
+ E1: Special case of the generalised exponential integral.
2225
+ li: Logarithmic integral.
2226
+ Li: Offset logarithmic integral.
2227
+
2228
+ References
2229
+ ==========
2230
+
2231
+ .. [1] https://en.wikipedia.org/wiki/Trigonometric_integral
2232
+
2233
+ """
2234
+
2235
+ _trigfunc = cosh
2236
+ _atzero = S.ComplexInfinity
2237
+
2238
+ @classmethod
2239
+ def _atinf(cls):
2240
+ return S.Infinity
2241
+
2242
+ @classmethod
2243
+ def _atneginf(cls):
2244
+ return S.Infinity
2245
+
2246
+ @classmethod
2247
+ def _minusfactor(cls, z):
2248
+ return Chi(z) + I*pi
2249
+
2250
+ @classmethod
2251
+ def _Ifactor(cls, z, sign):
2252
+ return Ci(z) + I*pi/2*sign
2253
+
2254
+ def _eval_rewrite_as_expint(self, z, **kwargs):
2255
+ return -I*pi/2 - (E1(z) + E1(exp_polar(I*pi)*z))/2
2256
+
2257
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
2258
+ arg = self.args[0].as_leading_term(x, logx=logx, cdir=cdir)
2259
+ arg0 = arg.subs(x, 0)
2260
+
2261
+ if arg0 is S.NaN:
2262
+ arg0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
2263
+ if arg0.is_zero:
2264
+ c, e = arg.as_coeff_exponent(x)
2265
+ logx = log(x) if logx is None else logx
2266
+ return log(c) + e*logx + EulerGamma
2267
+ elif arg0.is_finite:
2268
+ return self.func(arg0)
2269
+ else:
2270
+ return self
2271
+
2272
+
2273
+ ###############################################################################
2274
+ #################### FRESNEL INTEGRALS ########################################
2275
+ ###############################################################################
2276
+
2277
+ class FresnelIntegral(Function):
2278
+ """ Base class for the Fresnel integrals."""
2279
+
2280
+ unbranched = True
2281
+
2282
+ @classmethod
2283
+ def eval(cls, z):
2284
+ # Values at positive infinities signs
2285
+ # if any were extracted automatically
2286
+ if z is S.Infinity:
2287
+ return S.Half
2288
+
2289
+ # Value at zero
2290
+ if z.is_zero:
2291
+ return S.Zero
2292
+
2293
+ # Try to pull out factors of -1 and I
2294
+ prefact = S.One
2295
+ newarg = z
2296
+ changed = False
2297
+
2298
+ nz = newarg.extract_multiplicatively(-1)
2299
+ if nz is not None:
2300
+ prefact = -prefact
2301
+ newarg = nz
2302
+ changed = True
2303
+
2304
+ nz = newarg.extract_multiplicatively(I)
2305
+ if nz is not None:
2306
+ prefact = cls._sign*I*prefact
2307
+ newarg = nz
2308
+ changed = True
2309
+
2310
+ if changed:
2311
+ return prefact*cls(newarg)
2312
+
2313
+ def fdiff(self, argindex=1):
2314
+ if argindex == 1:
2315
+ return self._trigfunc(S.Half*pi*self.args[0]**2)
2316
+ else:
2317
+ raise ArgumentIndexError(self, argindex)
2318
+
2319
+ def _eval_is_extended_real(self):
2320
+ return self.args[0].is_extended_real
2321
+
2322
+ _eval_is_finite = _eval_is_extended_real
2323
+
2324
+ def _eval_is_zero(self):
2325
+ return self.args[0].is_zero
2326
+
2327
+ def _eval_conjugate(self):
2328
+ return self.func(self.args[0].conjugate())
2329
+
2330
+ as_real_imag = real_to_real_as_real_imag
2331
+
2332
+
2333
+ class fresnels(FresnelIntegral):
2334
+ r"""
2335
+ Fresnel integral S.
2336
+
2337
+ Explanation
2338
+ ===========
2339
+
2340
+ This function is defined by
2341
+
2342
+ .. math:: \operatorname{S}(z) = \int_0^z \sin{\frac{\pi}{2} t^2} \mathrm{d}t.
2343
+
2344
+ It is an entire function.
2345
+
2346
+ Examples
2347
+ ========
2348
+
2349
+ >>> from sympy import I, oo, fresnels
2350
+ >>> from sympy.abc import z
2351
+
2352
+ Several special values are known:
2353
+
2354
+ >>> fresnels(0)
2355
+ 0
2356
+ >>> fresnels(oo)
2357
+ 1/2
2358
+ >>> fresnels(-oo)
2359
+ -1/2
2360
+ >>> fresnels(I*oo)
2361
+ -I/2
2362
+ >>> fresnels(-I*oo)
2363
+ I/2
2364
+
2365
+ In general one can pull out factors of -1 and $i$ from the argument:
2366
+
2367
+ >>> fresnels(-z)
2368
+ -fresnels(z)
2369
+ >>> fresnels(I*z)
2370
+ -I*fresnels(z)
2371
+
2372
+ The Fresnel S integral obeys the mirror symmetry
2373
+ $\overline{S(z)} = S(\bar{z})$:
2374
+
2375
+ >>> from sympy import conjugate
2376
+ >>> conjugate(fresnels(z))
2377
+ fresnels(conjugate(z))
2378
+
2379
+ Differentiation with respect to $z$ is supported:
2380
+
2381
+ >>> from sympy import diff
2382
+ >>> diff(fresnels(z), z)
2383
+ sin(pi*z**2/2)
2384
+
2385
+ Defining the Fresnel functions via an integral:
2386
+
2387
+ >>> from sympy import integrate, pi, sin, expand_func
2388
+ >>> integrate(sin(pi*z**2/2), z)
2389
+ 3*fresnels(z)*gamma(3/4)/(4*gamma(7/4))
2390
+ >>> expand_func(integrate(sin(pi*z**2/2), z))
2391
+ fresnels(z)
2392
+
2393
+ We can numerically evaluate the Fresnel integral to arbitrary precision
2394
+ on the whole complex plane:
2395
+
2396
+ >>> fresnels(2).evalf(30)
2397
+ 0.343415678363698242195300815958
2398
+
2399
+ >>> fresnels(-2*I).evalf(30)
2400
+ 0.343415678363698242195300815958*I
2401
+
2402
+ See Also
2403
+ ========
2404
+
2405
+ fresnelc: Fresnel cosine integral.
2406
+
2407
+ References
2408
+ ==========
2409
+
2410
+ .. [1] https://en.wikipedia.org/wiki/Fresnel_integral
2411
+ .. [2] https://dlmf.nist.gov/7
2412
+ .. [3] https://mathworld.wolfram.com/FresnelIntegrals.html
2413
+ .. [4] https://functions.wolfram.com/GammaBetaErf/FresnelS
2414
+ .. [5] The converging factors for the fresnel integrals
2415
+ by John W. Wrench Jr. and Vicki Alley
2416
+
2417
+ """
2418
+ _trigfunc = sin
2419
+ _sign = -S.One
2420
+
2421
+ @staticmethod
2422
+ @cacheit
2423
+ def taylor_term(n, x, *previous_terms):
2424
+ if n < 0:
2425
+ return S.Zero
2426
+ else:
2427
+ x = sympify(x)
2428
+ if len(previous_terms) > 1:
2429
+ p = previous_terms[-1]
2430
+ return (-pi**2*x**4*(4*n - 1)/(8*n*(2*n + 1)*(4*n + 3))) * p
2431
+ else:
2432
+ return x**3 * (-x**4)**n * (S(2)**(-2*n - 1)*pi**(2*n + 1)) / ((4*n + 3)*factorial(2*n + 1))
2433
+
2434
+ def _eval_rewrite_as_erf(self, z, **kwargs):
2435
+ return (S.One + I)/4 * (erf((S.One + I)/2*sqrt(pi)*z) - I*erf((S.One - I)/2*sqrt(pi)*z))
2436
+
2437
+ def _eval_rewrite_as_hyper(self, z, **kwargs):
2438
+ return pi*z**3/6 * hyper([Rational(3, 4)], [Rational(3, 2), Rational(7, 4)], -pi**2*z**4/16)
2439
+
2440
+ def _eval_rewrite_as_meijerg(self, z, **kwargs):
2441
+ return (pi*z**Rational(9, 4) / (sqrt(2)*(z**2)**Rational(3, 4)*(-z)**Rational(3, 4))
2442
+ * meijerg([], [1], [Rational(3, 4)], [Rational(1, 4), 0], -pi**2*z**4/16))
2443
+
2444
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
2445
+ from sympy.series.order import Order
2446
+ arg = self.args[0].as_leading_term(x, logx=logx, cdir=cdir)
2447
+ arg0 = arg.subs(x, 0)
2448
+
2449
+ if arg0 is S.ComplexInfinity:
2450
+ arg0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
2451
+ if arg0.is_zero:
2452
+ return pi*arg**3/6
2453
+ elif arg0 in [S.Infinity, S.NegativeInfinity]:
2454
+ s = 1 if arg0 is S.Infinity else -1
2455
+ return s*S.Half + Order(x, x)
2456
+ else:
2457
+ return self.func(arg0)
2458
+
2459
+ def _eval_aseries(self, n, args0, x, logx):
2460
+ from sympy.series.order import Order
2461
+ point = args0[0]
2462
+
2463
+ # Expansion at oo and -oo
2464
+ if point in [S.Infinity, -S.Infinity]:
2465
+ z = self.args[0]
2466
+
2467
+ # expansion of S(x) = S1(x*sqrt(pi/2)), see reference[5] page 1-8
2468
+ # as only real infinities are dealt with, sin and cos are O(1)
2469
+ p = [S.NegativeOne**k * factorial(4*k + 1) /
2470
+ (2**(2*k + 2) * z**(4*k + 3) * 2**(2*k)*factorial(2*k))
2471
+ for k in range(0, n) if 4*k + 3 < n]
2472
+ q = [1/(2*z)] + [S.NegativeOne**k * factorial(4*k - 1) /
2473
+ (2**(2*k + 1) * z**(4*k + 1) * 2**(2*k - 1)*factorial(2*k - 1))
2474
+ for k in range(1, n) if 4*k + 1 < n]
2475
+
2476
+ p = [-sqrt(2/pi)*t for t in p]
2477
+ q = [-sqrt(2/pi)*t for t in q]
2478
+ s = 1 if point is S.Infinity else -1
2479
+ # The expansion at oo is 1/2 + some odd powers of z
2480
+ # To get the expansion at -oo, replace z by -z and flip the sign
2481
+ # The result -1/2 + the same odd powers of z as before.
2482
+ return s*S.Half + (sin(z**2)*Add(*p) + cos(z**2)*Add(*q)
2483
+ ).subs(x, sqrt(2/pi)*x) + Order(1/z**n, x)
2484
+
2485
+ # All other points are not handled
2486
+ return super()._eval_aseries(n, args0, x, logx)
2487
+
2488
+
2489
+ class fresnelc(FresnelIntegral):
2490
+ r"""
2491
+ Fresnel integral C.
2492
+
2493
+ Explanation
2494
+ ===========
2495
+
2496
+ This function is defined by
2497
+
2498
+ .. math:: \operatorname{C}(z) = \int_0^z \cos{\frac{\pi}{2} t^2} \mathrm{d}t.
2499
+
2500
+ It is an entire function.
2501
+
2502
+ Examples
2503
+ ========
2504
+
2505
+ >>> from sympy import I, oo, fresnelc
2506
+ >>> from sympy.abc import z
2507
+
2508
+ Several special values are known:
2509
+
2510
+ >>> fresnelc(0)
2511
+ 0
2512
+ >>> fresnelc(oo)
2513
+ 1/2
2514
+ >>> fresnelc(-oo)
2515
+ -1/2
2516
+ >>> fresnelc(I*oo)
2517
+ I/2
2518
+ >>> fresnelc(-I*oo)
2519
+ -I/2
2520
+
2521
+ In general one can pull out factors of -1 and $i$ from the argument:
2522
+
2523
+ >>> fresnelc(-z)
2524
+ -fresnelc(z)
2525
+ >>> fresnelc(I*z)
2526
+ I*fresnelc(z)
2527
+
2528
+ The Fresnel C integral obeys the mirror symmetry
2529
+ $\overline{C(z)} = C(\bar{z})$:
2530
+
2531
+ >>> from sympy import conjugate
2532
+ >>> conjugate(fresnelc(z))
2533
+ fresnelc(conjugate(z))
2534
+
2535
+ Differentiation with respect to $z$ is supported:
2536
+
2537
+ >>> from sympy import diff
2538
+ >>> diff(fresnelc(z), z)
2539
+ cos(pi*z**2/2)
2540
+
2541
+ Defining the Fresnel functions via an integral:
2542
+
2543
+ >>> from sympy import integrate, pi, cos, expand_func
2544
+ >>> integrate(cos(pi*z**2/2), z)
2545
+ fresnelc(z)*gamma(1/4)/(4*gamma(5/4))
2546
+ >>> expand_func(integrate(cos(pi*z**2/2), z))
2547
+ fresnelc(z)
2548
+
2549
+ We can numerically evaluate the Fresnel integral to arbitrary precision
2550
+ on the whole complex plane:
2551
+
2552
+ >>> fresnelc(2).evalf(30)
2553
+ 0.488253406075340754500223503357
2554
+
2555
+ >>> fresnelc(-2*I).evalf(30)
2556
+ -0.488253406075340754500223503357*I
2557
+
2558
+ See Also
2559
+ ========
2560
+
2561
+ fresnels: Fresnel sine integral.
2562
+
2563
+ References
2564
+ ==========
2565
+
2566
+ .. [1] https://en.wikipedia.org/wiki/Fresnel_integral
2567
+ .. [2] https://dlmf.nist.gov/7
2568
+ .. [3] https://mathworld.wolfram.com/FresnelIntegrals.html
2569
+ .. [4] https://functions.wolfram.com/GammaBetaErf/FresnelC
2570
+ .. [5] The converging factors for the fresnel integrals
2571
+ by John W. Wrench Jr. and Vicki Alley
2572
+
2573
+ """
2574
+ _trigfunc = cos
2575
+ _sign = S.One
2576
+
2577
+ @staticmethod
2578
+ @cacheit
2579
+ def taylor_term(n, x, *previous_terms):
2580
+ if n < 0:
2581
+ return S.Zero
2582
+ else:
2583
+ x = sympify(x)
2584
+ if len(previous_terms) > 1:
2585
+ p = previous_terms[-1]
2586
+ return (-pi**2*x**4*(4*n - 3)/(8*n*(2*n - 1)*(4*n + 1))) * p
2587
+ else:
2588
+ return x * (-x**4)**n * (S(2)**(-2*n)*pi**(2*n)) / ((4*n + 1)*factorial(2*n))
2589
+
2590
+ def _eval_rewrite_as_erf(self, z, **kwargs):
2591
+ return (S.One - I)/4 * (erf((S.One + I)/2*sqrt(pi)*z) + I*erf((S.One - I)/2*sqrt(pi)*z))
2592
+
2593
+ def _eval_rewrite_as_hyper(self, z, **kwargs):
2594
+ return z * hyper([Rational(1, 4)], [S.Half, Rational(5, 4)], -pi**2*z**4/16)
2595
+
2596
+ def _eval_rewrite_as_meijerg(self, z, **kwargs):
2597
+ return (pi*z**Rational(3, 4) / (sqrt(2)*root(z**2, 4)*root(-z, 4))
2598
+ * meijerg([], [1], [Rational(1, 4)], [Rational(3, 4), 0], -pi**2*z**4/16))
2599
+
2600
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
2601
+ from sympy.series.order import Order
2602
+ arg = self.args[0].as_leading_term(x, logx=logx, cdir=cdir)
2603
+ arg0 = arg.subs(x, 0)
2604
+
2605
+ if arg0 is S.ComplexInfinity:
2606
+ arg0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
2607
+ if arg0.is_zero:
2608
+ return arg
2609
+ elif arg0 in [S.Infinity, S.NegativeInfinity]:
2610
+ s = 1 if arg0 is S.Infinity else -1
2611
+ return s*S.Half + Order(x, x)
2612
+ else:
2613
+ return self.func(arg0)
2614
+
2615
+ def _eval_aseries(self, n, args0, x, logx):
2616
+ from sympy.series.order import Order
2617
+ point = args0[0]
2618
+
2619
+ # Expansion at oo
2620
+ if point in [S.Infinity, -S.Infinity]:
2621
+ z = self.args[0]
2622
+
2623
+ # expansion of C(x) = C1(x*sqrt(pi/2)), see reference[5] page 1-8
2624
+ # as only real infinities are dealt with, sin and cos are O(1)
2625
+ p = [S.NegativeOne**k * factorial(4*k + 1) /
2626
+ (2**(2*k + 2) * z**(4*k + 3) * 2**(2*k)*factorial(2*k))
2627
+ for k in range(n) if 4*k + 3 < n]
2628
+ q = [1/(2*z)] + [S.NegativeOne**k * factorial(4*k - 1) /
2629
+ (2**(2*k + 1) * z**(4*k + 1) * 2**(2*k - 1)*factorial(2*k - 1))
2630
+ for k in range(1, n) if 4*k + 1 < n]
2631
+
2632
+ p = [-sqrt(2/pi)*t for t in p]
2633
+ q = [ sqrt(2/pi)*t for t in q]
2634
+ s = 1 if point is S.Infinity else -1
2635
+ # The expansion at oo is 1/2 + some odd powers of z
2636
+ # To get the expansion at -oo, replace z by -z and flip the sign
2637
+ # The result -1/2 + the same odd powers of z as before.
2638
+ return s*S.Half + (cos(z**2)*Add(*p) + sin(z**2)*Add(*q)
2639
+ ).subs(x, sqrt(2/pi)*x) + Order(1/z**n, x)
2640
+
2641
+ # All other points are not handled
2642
+ return super()._eval_aseries(n, args0, x, logx)
2643
+
2644
+
2645
+ ###############################################################################
2646
+ #################### HELPER FUNCTIONS #########################################
2647
+ ###############################################################################
2648
+
2649
+
2650
+ class _erfs(Function):
2651
+ """
2652
+ Helper function to make the $\\mathrm{erf}(z)$ function
2653
+ tractable for the Gruntz algorithm.
2654
+
2655
+ """
2656
+ @classmethod
2657
+ def eval(cls, arg):
2658
+ if arg.is_zero:
2659
+ return S.One
2660
+
2661
+ def _eval_aseries(self, n, args0, x, logx):
2662
+ from sympy.series.order import Order
2663
+ point = args0[0]
2664
+
2665
+ # Expansion at oo
2666
+ if point is S.Infinity:
2667
+ z = self.args[0]
2668
+ l = [1/sqrt(pi) * factorial(2*k)*(-S(
2669
+ 4))**(-k)/factorial(k) * (1/z)**(2*k + 1) for k in range(n)]
2670
+ o = Order(1/z**(2*n + 1), x)
2671
+ # It is very inefficient to first add the order and then do the nseries
2672
+ return (Add(*l))._eval_nseries(x, n, logx) + o
2673
+
2674
+ # Expansion at I*oo
2675
+ t = point.extract_multiplicatively(I)
2676
+ if t is S.Infinity:
2677
+ z = self.args[0]
2678
+ # TODO: is the series really correct?
2679
+ l = [1/sqrt(pi) * factorial(2*k)*(-S(
2680
+ 4))**(-k)/factorial(k) * (1/z)**(2*k + 1) for k in range(n)]
2681
+ o = Order(1/z**(2*n + 1), x)
2682
+ # It is very inefficient to first add the order and then do the nseries
2683
+ return (Add(*l))._eval_nseries(x, n, logx) + o
2684
+
2685
+ # All other points are not handled
2686
+ return super()._eval_aseries(n, args0, x, logx)
2687
+
2688
+ def fdiff(self, argindex=1):
2689
+ if argindex == 1:
2690
+ z = self.args[0]
2691
+ return -2/sqrt(pi) + 2*z*_erfs(z)
2692
+ else:
2693
+ raise ArgumentIndexError(self, argindex)
2694
+
2695
+ def _eval_rewrite_as_intractable(self, z, **kwargs):
2696
+ return (S.One - erf(z))*exp(z**2)
2697
+
2698
+
2699
+ class _eis(Function):
2700
+ """
2701
+ Helper function to make the $\\mathrm{Ei}(z)$ and $\\mathrm{li}(z)$
2702
+ functions tractable for the Gruntz algorithm.
2703
+
2704
+ """
2705
+
2706
+
2707
+ def _eval_aseries(self, n, args0, x, logx):
2708
+ from sympy.series.order import Order
2709
+ if args0[0] != S.Infinity:
2710
+ return super(_erfs, self)._eval_aseries(n, args0, x, logx)
2711
+
2712
+ z = self.args[0]
2713
+ l = [factorial(k) * (1/z)**(k + 1) for k in range(n)]
2714
+ o = Order(1/z**(n + 1), x)
2715
+ # It is very inefficient to first add the order and then do the nseries
2716
+ return (Add(*l))._eval_nseries(x, n, logx) + o
2717
+
2718
+
2719
+ def fdiff(self, argindex=1):
2720
+ if argindex == 1:
2721
+ z = self.args[0]
2722
+ return S.One / z - _eis(z)
2723
+ else:
2724
+ raise ArgumentIndexError(self, argindex)
2725
+
2726
+ def _eval_rewrite_as_intractable(self, z, **kwargs):
2727
+ return exp(-z)*Ei(z)
2728
+
2729
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
2730
+ x0 = self.args[0].limit(x, 0)
2731
+ if x0.is_zero:
2732
+ f = self._eval_rewrite_as_intractable(*self.args)
2733
+ return f._eval_as_leading_term(x, logx=logx, cdir=cdir)
2734
+ return super()._eval_as_leading_term(x, logx=logx, cdir=cdir)
2735
+
2736
+ def _eval_nseries(self, x, n, logx, cdir=0):
2737
+ x0 = self.args[0].limit(x, 0)
2738
+ if x0.is_zero:
2739
+ f = self._eval_rewrite_as_intractable(*self.args)
2740
+ return f._eval_nseries(x, n, logx)
2741
+ return super()._eval_nseries(x, n, logx)
env-llmeval/lib/python3.10/site-packages/sympy/functions/special/hyper.py ADDED
@@ -0,0 +1,1152 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ """Hypergeometric and Meijer G-functions"""
2
+ from functools import reduce
3
+
4
+ from sympy.core import S, ilcm, Mod
5
+ from sympy.core.add import Add
6
+ from sympy.core.expr import Expr
7
+ from sympy.core.function import Function, Derivative, ArgumentIndexError
8
+
9
+ from sympy.core.containers import Tuple
10
+ from sympy.core.mul import Mul
11
+ from sympy.core.numbers import I, pi, oo, zoo
12
+ from sympy.core.relational import Ne
13
+ from sympy.core.sorting import default_sort_key
14
+ from sympy.core.symbol import Dummy
15
+
16
+ from sympy.functions import (sqrt, exp, log, sin, cos, asin, atan,
17
+ sinh, cosh, asinh, acosh, atanh, acoth)
18
+ from sympy.functions import factorial, RisingFactorial
19
+ from sympy.functions.elementary.complexes import Abs, re, unpolarify
20
+ from sympy.functions.elementary.exponential import exp_polar
21
+ from sympy.functions.elementary.integers import ceiling
22
+ from sympy.functions.elementary.piecewise import Piecewise
23
+ from sympy.logic.boolalg import (And, Or)
24
+
25
+ class TupleArg(Tuple):
26
+ def limit(self, x, xlim, dir='+'):
27
+ """ Compute limit x->xlim.
28
+ """
29
+ from sympy.series.limits import limit
30
+ return TupleArg(*[limit(f, x, xlim, dir) for f in self.args])
31
+
32
+
33
+ # TODO should __new__ accept **options?
34
+ # TODO should constructors should check if parameters are sensible?
35
+
36
+
37
+ def _prep_tuple(v):
38
+ """
39
+ Turn an iterable argument *v* into a tuple and unpolarify, since both
40
+ hypergeometric and meijer g-functions are unbranched in their parameters.
41
+
42
+ Examples
43
+ ========
44
+
45
+ >>> from sympy.functions.special.hyper import _prep_tuple
46
+ >>> _prep_tuple([1, 2, 3])
47
+ (1, 2, 3)
48
+ >>> _prep_tuple((4, 5))
49
+ (4, 5)
50
+ >>> _prep_tuple((7, 8, 9))
51
+ (7, 8, 9)
52
+
53
+ """
54
+ return TupleArg(*[unpolarify(x) for x in v])
55
+
56
+
57
+ class TupleParametersBase(Function):
58
+ """ Base class that takes care of differentiation, when some of
59
+ the arguments are actually tuples. """
60
+ # This is not deduced automatically since there are Tuples as arguments.
61
+ is_commutative = True
62
+
63
+ def _eval_derivative(self, s):
64
+ try:
65
+ res = 0
66
+ if self.args[0].has(s) or self.args[1].has(s):
67
+ for i, p in enumerate(self._diffargs):
68
+ m = self._diffargs[i].diff(s)
69
+ if m != 0:
70
+ res += self.fdiff((1, i))*m
71
+ return res + self.fdiff(3)*self.args[2].diff(s)
72
+ except (ArgumentIndexError, NotImplementedError):
73
+ return Derivative(self, s)
74
+
75
+
76
+ class hyper(TupleParametersBase):
77
+ r"""
78
+ The generalized hypergeometric function is defined by a series where
79
+ the ratios of successive terms are a rational function of the summation
80
+ index. When convergent, it is continued analytically to the largest
81
+ possible domain.
82
+
83
+ Explanation
84
+ ===========
85
+
86
+ The hypergeometric function depends on two vectors of parameters, called
87
+ the numerator parameters $a_p$, and the denominator parameters
88
+ $b_q$. It also has an argument $z$. The series definition is
89
+
90
+ .. math ::
91
+ {}_pF_q\left(\begin{matrix} a_1, \cdots, a_p \\ b_1, \cdots, b_q \end{matrix}
92
+ \middle| z \right)
93
+ = \sum_{n=0}^\infty \frac{(a_1)_n \cdots (a_p)_n}{(b_1)_n \cdots (b_q)_n}
94
+ \frac{z^n}{n!},
95
+
96
+ where $(a)_n = (a)(a+1)\cdots(a+n-1)$ denotes the rising factorial.
97
+
98
+ If one of the $b_q$ is a non-positive integer then the series is
99
+ undefined unless one of the $a_p$ is a larger (i.e., smaller in
100
+ magnitude) non-positive integer. If none of the $b_q$ is a
101
+ non-positive integer and one of the $a_p$ is a non-positive
102
+ integer, then the series reduces to a polynomial. To simplify the
103
+ following discussion, we assume that none of the $a_p$ or
104
+ $b_q$ is a non-positive integer. For more details, see the
105
+ references.
106
+
107
+ The series converges for all $z$ if $p \le q$, and thus
108
+ defines an entire single-valued function in this case. If $p =
109
+ q+1$ the series converges for $|z| < 1$, and can be continued
110
+ analytically into a half-plane. If $p > q+1$ the series is
111
+ divergent for all $z$.
112
+
113
+ Please note the hypergeometric function constructor currently does *not*
114
+ check if the parameters actually yield a well-defined function.
115
+
116
+ Examples
117
+ ========
118
+
119
+ The parameters $a_p$ and $b_q$ can be passed as arbitrary
120
+ iterables, for example:
121
+
122
+ >>> from sympy import hyper
123
+ >>> from sympy.abc import x, n, a
124
+ >>> hyper((1, 2, 3), [3, 4], x)
125
+ hyper((1, 2, 3), (3, 4), x)
126
+
127
+ There is also pretty printing (it looks better using Unicode):
128
+
129
+ >>> from sympy import pprint
130
+ >>> pprint(hyper((1, 2, 3), [3, 4], x), use_unicode=False)
131
+ _
132
+ |_ /1, 2, 3 | \
133
+ | | | x|
134
+ 3 2 \ 3, 4 | /
135
+
136
+ The parameters must always be iterables, even if they are vectors of
137
+ length one or zero:
138
+
139
+ >>> hyper((1, ), [], x)
140
+ hyper((1,), (), x)
141
+
142
+ But of course they may be variables (but if they depend on $x$ then you
143
+ should not expect much implemented functionality):
144
+
145
+ >>> hyper((n, a), (n**2,), x)
146
+ hyper((n, a), (n**2,), x)
147
+
148
+ The hypergeometric function generalizes many named special functions.
149
+ The function ``hyperexpand()`` tries to express a hypergeometric function
150
+ using named special functions. For example:
151
+
152
+ >>> from sympy import hyperexpand
153
+ >>> hyperexpand(hyper([], [], x))
154
+ exp(x)
155
+
156
+ You can also use ``expand_func()``:
157
+
158
+ >>> from sympy import expand_func
159
+ >>> expand_func(x*hyper([1, 1], [2], -x))
160
+ log(x + 1)
161
+
162
+ More examples:
163
+
164
+ >>> from sympy import S
165
+ >>> hyperexpand(hyper([], [S(1)/2], -x**2/4))
166
+ cos(x)
167
+ >>> hyperexpand(x*hyper([S(1)/2, S(1)/2], [S(3)/2], x**2))
168
+ asin(x)
169
+
170
+ We can also sometimes ``hyperexpand()`` parametric functions:
171
+
172
+ >>> from sympy.abc import a
173
+ >>> hyperexpand(hyper([-a], [], x))
174
+ (1 - x)**a
175
+
176
+ See Also
177
+ ========
178
+
179
+ sympy.simplify.hyperexpand
180
+ gamma
181
+ meijerg
182
+
183
+ References
184
+ ==========
185
+
186
+ .. [1] Luke, Y. L. (1969), The Special Functions and Their Approximations,
187
+ Volume 1
188
+ .. [2] https://en.wikipedia.org/wiki/Generalized_hypergeometric_function
189
+
190
+ """
191
+
192
+
193
+ def __new__(cls, ap, bq, z, **kwargs):
194
+ # TODO should we check convergence conditions?
195
+ return Function.__new__(cls, _prep_tuple(ap), _prep_tuple(bq), z, **kwargs)
196
+
197
+ @classmethod
198
+ def eval(cls, ap, bq, z):
199
+ if len(ap) <= len(bq) or (len(ap) == len(bq) + 1 and (Abs(z) <= 1) == True):
200
+ nz = unpolarify(z)
201
+ if z != nz:
202
+ return hyper(ap, bq, nz)
203
+
204
+ def fdiff(self, argindex=3):
205
+ if argindex != 3:
206
+ raise ArgumentIndexError(self, argindex)
207
+ nap = Tuple(*[a + 1 for a in self.ap])
208
+ nbq = Tuple(*[b + 1 for b in self.bq])
209
+ fac = Mul(*self.ap)/Mul(*self.bq)
210
+ return fac*hyper(nap, nbq, self.argument)
211
+
212
+ def _eval_expand_func(self, **hints):
213
+ from sympy.functions.special.gamma_functions import gamma
214
+ from sympy.simplify.hyperexpand import hyperexpand
215
+ if len(self.ap) == 2 and len(self.bq) == 1 and self.argument == 1:
216
+ a, b = self.ap
217
+ c = self.bq[0]
218
+ return gamma(c)*gamma(c - a - b)/gamma(c - a)/gamma(c - b)
219
+ return hyperexpand(self)
220
+
221
+ def _eval_rewrite_as_Sum(self, ap, bq, z, **kwargs):
222
+ from sympy.concrete.summations import Sum
223
+ n = Dummy("n", integer=True)
224
+ rfap = [RisingFactorial(a, n) for a in ap]
225
+ rfbq = [RisingFactorial(b, n) for b in bq]
226
+ coeff = Mul(*rfap) / Mul(*rfbq)
227
+ return Piecewise((Sum(coeff * z**n / factorial(n), (n, 0, oo)),
228
+ self.convergence_statement), (self, True))
229
+
230
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
231
+ arg = self.args[2]
232
+ x0 = arg.subs(x, 0)
233
+ if x0 is S.NaN:
234
+ x0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
235
+
236
+ if x0 is S.Zero:
237
+ return S.One
238
+ return super()._eval_as_leading_term(x, logx=logx, cdir=cdir)
239
+
240
+ def _eval_nseries(self, x, n, logx, cdir=0):
241
+
242
+ from sympy.series.order import Order
243
+
244
+ arg = self.args[2]
245
+ x0 = arg.limit(x, 0)
246
+ ap = self.args[0]
247
+ bq = self.args[1]
248
+
249
+ if x0 != 0:
250
+ return super()._eval_nseries(x, n, logx)
251
+
252
+ terms = []
253
+
254
+ for i in range(n):
255
+ num = Mul(*[RisingFactorial(a, i) for a in ap])
256
+ den = Mul(*[RisingFactorial(b, i) for b in bq])
257
+ terms.append(((num/den) * (arg**i)) / factorial(i))
258
+
259
+ return (Add(*terms) + Order(x**n,x))
260
+
261
+ @property
262
+ def argument(self):
263
+ """ Argument of the hypergeometric function. """
264
+ return self.args[2]
265
+
266
+ @property
267
+ def ap(self):
268
+ """ Numerator parameters of the hypergeometric function. """
269
+ return Tuple(*self.args[0])
270
+
271
+ @property
272
+ def bq(self):
273
+ """ Denominator parameters of the hypergeometric function. """
274
+ return Tuple(*self.args[1])
275
+
276
+ @property
277
+ def _diffargs(self):
278
+ return self.ap + self.bq
279
+
280
+ @property
281
+ def eta(self):
282
+ """ A quantity related to the convergence of the series. """
283
+ return sum(self.ap) - sum(self.bq)
284
+
285
+ @property
286
+ def radius_of_convergence(self):
287
+ """
288
+ Compute the radius of convergence of the defining series.
289
+
290
+ Explanation
291
+ ===========
292
+
293
+ Note that even if this is not ``oo``, the function may still be
294
+ evaluated outside of the radius of convergence by analytic
295
+ continuation. But if this is zero, then the function is not actually
296
+ defined anywhere else.
297
+
298
+ Examples
299
+ ========
300
+
301
+ >>> from sympy import hyper
302
+ >>> from sympy.abc import z
303
+ >>> hyper((1, 2), [3], z).radius_of_convergence
304
+ 1
305
+ >>> hyper((1, 2, 3), [4], z).radius_of_convergence
306
+ 0
307
+ >>> hyper((1, 2), (3, 4), z).radius_of_convergence
308
+ oo
309
+
310
+ """
311
+ if any(a.is_integer and (a <= 0) == True for a in self.ap + self.bq):
312
+ aints = [a for a in self.ap if a.is_Integer and (a <= 0) == True]
313
+ bints = [a for a in self.bq if a.is_Integer and (a <= 0) == True]
314
+ if len(aints) < len(bints):
315
+ return S.Zero
316
+ popped = False
317
+ for b in bints:
318
+ cancelled = False
319
+ while aints:
320
+ a = aints.pop()
321
+ if a >= b:
322
+ cancelled = True
323
+ break
324
+ popped = True
325
+ if not cancelled:
326
+ return S.Zero
327
+ if aints or popped:
328
+ # There are still non-positive numerator parameters.
329
+ # This is a polynomial.
330
+ return oo
331
+ if len(self.ap) == len(self.bq) + 1:
332
+ return S.One
333
+ elif len(self.ap) <= len(self.bq):
334
+ return oo
335
+ else:
336
+ return S.Zero
337
+
338
+ @property
339
+ def convergence_statement(self):
340
+ """ Return a condition on z under which the series converges. """
341
+ R = self.radius_of_convergence
342
+ if R == 0:
343
+ return False
344
+ if R == oo:
345
+ return True
346
+ # The special functions and their approximations, page 44
347
+ e = self.eta
348
+ z = self.argument
349
+ c1 = And(re(e) < 0, abs(z) <= 1)
350
+ c2 = And(0 <= re(e), re(e) < 1, abs(z) <= 1, Ne(z, 1))
351
+ c3 = And(re(e) >= 1, abs(z) < 1)
352
+ return Or(c1, c2, c3)
353
+
354
+ def _eval_simplify(self, **kwargs):
355
+ from sympy.simplify.hyperexpand import hyperexpand
356
+ return hyperexpand(self)
357
+
358
+
359
+ class meijerg(TupleParametersBase):
360
+ r"""
361
+ The Meijer G-function is defined by a Mellin-Barnes type integral that
362
+ resembles an inverse Mellin transform. It generalizes the hypergeometric
363
+ functions.
364
+
365
+ Explanation
366
+ ===========
367
+
368
+ The Meijer G-function depends on four sets of parameters. There are
369
+ "*numerator parameters*"
370
+ $a_1, \ldots, a_n$ and $a_{n+1}, \ldots, a_p$, and there are
371
+ "*denominator parameters*"
372
+ $b_1, \ldots, b_m$ and $b_{m+1}, \ldots, b_q$.
373
+ Confusingly, it is traditionally denoted as follows (note the position
374
+ of $m$, $n$, $p$, $q$, and how they relate to the lengths of the four
375
+ parameter vectors):
376
+
377
+ .. math ::
378
+ G_{p,q}^{m,n} \left(\begin{matrix}a_1, \cdots, a_n & a_{n+1}, \cdots, a_p \\
379
+ b_1, \cdots, b_m & b_{m+1}, \cdots, b_q
380
+ \end{matrix} \middle| z \right).
381
+
382
+ However, in SymPy the four parameter vectors are always available
383
+ separately (see examples), so that there is no need to keep track of the
384
+ decorating sub- and super-scripts on the G symbol.
385
+
386
+ The G function is defined as the following integral:
387
+
388
+ .. math ::
389
+ \frac{1}{2 \pi i} \int_L \frac{\prod_{j=1}^m \Gamma(b_j - s)
390
+ \prod_{j=1}^n \Gamma(1 - a_j + s)}{\prod_{j=m+1}^q \Gamma(1- b_j +s)
391
+ \prod_{j=n+1}^p \Gamma(a_j - s)} z^s \mathrm{d}s,
392
+
393
+ where $\Gamma(z)$ is the gamma function. There are three possible
394
+ contours which we will not describe in detail here (see the references).
395
+ If the integral converges along more than one of them, the definitions
396
+ agree. The contours all separate the poles of $\Gamma(1-a_j+s)$
397
+ from the poles of $\Gamma(b_k-s)$, so in particular the G function
398
+ is undefined if $a_j - b_k \in \mathbb{Z}_{>0}$ for some
399
+ $j \le n$ and $k \le m$.
400
+
401
+ The conditions under which one of the contours yields a convergent integral
402
+ are complicated and we do not state them here, see the references.
403
+
404
+ Please note currently the Meijer G-function constructor does *not* check any
405
+ convergence conditions.
406
+
407
+ Examples
408
+ ========
409
+
410
+ You can pass the parameters either as four separate vectors:
411
+
412
+ >>> from sympy import meijerg, Tuple, pprint
413
+ >>> from sympy.abc import x, a
414
+ >>> pprint(meijerg((1, 2), (a, 4), (5,), [], x), use_unicode=False)
415
+ __1, 2 /1, 2 a, 4 | \
416
+ /__ | | x|
417
+ \_|4, 1 \ 5 | /
418
+
419
+ Or as two nested vectors:
420
+
421
+ >>> pprint(meijerg([(1, 2), (3, 4)], ([5], Tuple()), x), use_unicode=False)
422
+ __1, 2 /1, 2 3, 4 | \
423
+ /__ | | x|
424
+ \_|4, 1 \ 5 | /
425
+
426
+ As with the hypergeometric function, the parameters may be passed as
427
+ arbitrary iterables. Vectors of length zero and one also have to be
428
+ passed as iterables. The parameters need not be constants, but if they
429
+ depend on the argument then not much implemented functionality should be
430
+ expected.
431
+
432
+ All the subvectors of parameters are available:
433
+
434
+ >>> from sympy import pprint
435
+ >>> g = meijerg([1], [2], [3], [4], x)
436
+ >>> pprint(g, use_unicode=False)
437
+ __1, 1 /1 2 | \
438
+ /__ | | x|
439
+ \_|2, 2 \3 4 | /
440
+ >>> g.an
441
+ (1,)
442
+ >>> g.ap
443
+ (1, 2)
444
+ >>> g.aother
445
+ (2,)
446
+ >>> g.bm
447
+ (3,)
448
+ >>> g.bq
449
+ (3, 4)
450
+ >>> g.bother
451
+ (4,)
452
+
453
+ The Meijer G-function generalizes the hypergeometric functions.
454
+ In some cases it can be expressed in terms of hypergeometric functions,
455
+ using Slater's theorem. For example:
456
+
457
+ >>> from sympy import hyperexpand
458
+ >>> from sympy.abc import a, b, c
459
+ >>> hyperexpand(meijerg([a], [], [c], [b], x), allow_hyper=True)
460
+ x**c*gamma(-a + c + 1)*hyper((-a + c + 1,),
461
+ (-b + c + 1,), -x)/gamma(-b + c + 1)
462
+
463
+ Thus the Meijer G-function also subsumes many named functions as special
464
+ cases. You can use ``expand_func()`` or ``hyperexpand()`` to (try to)
465
+ rewrite a Meijer G-function in terms of named special functions. For
466
+ example:
467
+
468
+ >>> from sympy import expand_func, S
469
+ >>> expand_func(meijerg([[],[]], [[0],[]], -x))
470
+ exp(x)
471
+ >>> hyperexpand(meijerg([[],[]], [[S(1)/2],[0]], (x/2)**2))
472
+ sin(x)/sqrt(pi)
473
+
474
+ See Also
475
+ ========
476
+
477
+ hyper
478
+ sympy.simplify.hyperexpand
479
+
480
+ References
481
+ ==========
482
+
483
+ .. [1] Luke, Y. L. (1969), The Special Functions and Their Approximations,
484
+ Volume 1
485
+ .. [2] https://en.wikipedia.org/wiki/Meijer_G-function
486
+
487
+ """
488
+
489
+
490
+ def __new__(cls, *args, **kwargs):
491
+ if len(args) == 5:
492
+ args = [(args[0], args[1]), (args[2], args[3]), args[4]]
493
+ if len(args) != 3:
494
+ raise TypeError("args must be either as, as', bs, bs', z or "
495
+ "as, bs, z")
496
+
497
+ def tr(p):
498
+ if len(p) != 2:
499
+ raise TypeError("wrong argument")
500
+ return TupleArg(_prep_tuple(p[0]), _prep_tuple(p[1]))
501
+
502
+ arg0, arg1 = tr(args[0]), tr(args[1])
503
+ if Tuple(arg0, arg1).has(oo, zoo, -oo):
504
+ raise ValueError("G-function parameters must be finite")
505
+ if any((a - b).is_Integer and a - b > 0
506
+ for a in arg0[0] for b in arg1[0]):
507
+ raise ValueError("no parameter a1, ..., an may differ from "
508
+ "any b1, ..., bm by a positive integer")
509
+
510
+ # TODO should we check convergence conditions?
511
+ return Function.__new__(cls, arg0, arg1, args[2], **kwargs)
512
+
513
+ def fdiff(self, argindex=3):
514
+ if argindex != 3:
515
+ return self._diff_wrt_parameter(argindex[1])
516
+ if len(self.an) >= 1:
517
+ a = list(self.an)
518
+ a[0] -= 1
519
+ G = meijerg(a, self.aother, self.bm, self.bother, self.argument)
520
+ return 1/self.argument * ((self.an[0] - 1)*self + G)
521
+ elif len(self.bm) >= 1:
522
+ b = list(self.bm)
523
+ b[0] += 1
524
+ G = meijerg(self.an, self.aother, b, self.bother, self.argument)
525
+ return 1/self.argument * (self.bm[0]*self - G)
526
+ else:
527
+ return S.Zero
528
+
529
+ def _diff_wrt_parameter(self, idx):
530
+ # Differentiation wrt a parameter can only be done in very special
531
+ # cases. In particular, if we want to differentiate with respect to
532
+ # `a`, all other gamma factors have to reduce to rational functions.
533
+ #
534
+ # Let MT denote mellin transform. Suppose T(-s) is the gamma factor
535
+ # appearing in the definition of G. Then
536
+ #
537
+ # MT(log(z)G(z)) = d/ds T(s) = d/da T(s) + ...
538
+ #
539
+ # Thus d/da G(z) = log(z)G(z) - ...
540
+ # The ... can be evaluated as a G function under the above conditions,
541
+ # the formula being most easily derived by using
542
+ #
543
+ # d Gamma(s + n) Gamma(s + n) / 1 1 1 \
544
+ # -- ------------ = ------------ | - + ---- + ... + --------- |
545
+ # ds Gamma(s) Gamma(s) \ s s + 1 s + n - 1 /
546
+ #
547
+ # which follows from the difference equation of the digamma function.
548
+ # (There is a similar equation for -n instead of +n).
549
+
550
+ # We first figure out how to pair the parameters.
551
+ an = list(self.an)
552
+ ap = list(self.aother)
553
+ bm = list(self.bm)
554
+ bq = list(self.bother)
555
+ if idx < len(an):
556
+ an.pop(idx)
557
+ else:
558
+ idx -= len(an)
559
+ if idx < len(ap):
560
+ ap.pop(idx)
561
+ else:
562
+ idx -= len(ap)
563
+ if idx < len(bm):
564
+ bm.pop(idx)
565
+ else:
566
+ bq.pop(idx - len(bm))
567
+ pairs1 = []
568
+ pairs2 = []
569
+ for l1, l2, pairs in [(an, bq, pairs1), (ap, bm, pairs2)]:
570
+ while l1:
571
+ x = l1.pop()
572
+ found = None
573
+ for i, y in enumerate(l2):
574
+ if not Mod((x - y).simplify(), 1):
575
+ found = i
576
+ break
577
+ if found is None:
578
+ raise NotImplementedError('Derivative not expressible '
579
+ 'as G-function?')
580
+ y = l2[i]
581
+ l2.pop(i)
582
+ pairs.append((x, y))
583
+
584
+ # Now build the result.
585
+ res = log(self.argument)*self
586
+
587
+ for a, b in pairs1:
588
+ sign = 1
589
+ n = a - b
590
+ base = b
591
+ if n < 0:
592
+ sign = -1
593
+ n = b - a
594
+ base = a
595
+ for k in range(n):
596
+ res -= sign*meijerg(self.an + (base + k + 1,), self.aother,
597
+ self.bm, self.bother + (base + k + 0,),
598
+ self.argument)
599
+
600
+ for a, b in pairs2:
601
+ sign = 1
602
+ n = b - a
603
+ base = a
604
+ if n < 0:
605
+ sign = -1
606
+ n = a - b
607
+ base = b
608
+ for k in range(n):
609
+ res -= sign*meijerg(self.an, self.aother + (base + k + 1,),
610
+ self.bm + (base + k + 0,), self.bother,
611
+ self.argument)
612
+
613
+ return res
614
+
615
+ def get_period(self):
616
+ """
617
+ Return a number $P$ such that $G(x*exp(I*P)) == G(x)$.
618
+
619
+ Examples
620
+ ========
621
+
622
+ >>> from sympy import meijerg, pi, S
623
+ >>> from sympy.abc import z
624
+
625
+ >>> meijerg([1], [], [], [], z).get_period()
626
+ 2*pi
627
+ >>> meijerg([pi], [], [], [], z).get_period()
628
+ oo
629
+ >>> meijerg([1, 2], [], [], [], z).get_period()
630
+ oo
631
+ >>> meijerg([1,1], [2], [1, S(1)/2, S(1)/3], [1], z).get_period()
632
+ 12*pi
633
+
634
+ """
635
+ # This follows from slater's theorem.
636
+ def compute(l):
637
+ # first check that no two differ by an integer
638
+ for i, b in enumerate(l):
639
+ if not b.is_Rational:
640
+ return oo
641
+ for j in range(i + 1, len(l)):
642
+ if not Mod((b - l[j]).simplify(), 1):
643
+ return oo
644
+ return reduce(ilcm, (x.q for x in l), 1)
645
+ beta = compute(self.bm)
646
+ alpha = compute(self.an)
647
+ p, q = len(self.ap), len(self.bq)
648
+ if p == q:
649
+ if oo in (alpha, beta):
650
+ return oo
651
+ return 2*pi*ilcm(alpha, beta)
652
+ elif p < q:
653
+ return 2*pi*beta
654
+ else:
655
+ return 2*pi*alpha
656
+
657
+ def _eval_expand_func(self, **hints):
658
+ from sympy.simplify.hyperexpand import hyperexpand
659
+ return hyperexpand(self)
660
+
661
+ def _eval_evalf(self, prec):
662
+ # The default code is insufficient for polar arguments.
663
+ # mpmath provides an optional argument "r", which evaluates
664
+ # G(z**(1/r)). I am not sure what its intended use is, but we hijack it
665
+ # here in the following way: to evaluate at a number z of |argument|
666
+ # less than (say) n*pi, we put r=1/n, compute z' = root(z, n)
667
+ # (carefully so as not to loose the branch information), and evaluate
668
+ # G(z'**(1/r)) = G(z'**n) = G(z).
669
+ import mpmath
670
+ znum = self.argument._eval_evalf(prec)
671
+ if znum.has(exp_polar):
672
+ znum, branch = znum.as_coeff_mul(exp_polar)
673
+ if len(branch) != 1:
674
+ return
675
+ branch = branch[0].args[0]/I
676
+ else:
677
+ branch = S.Zero
678
+ n = ceiling(abs(branch/pi)) + 1
679
+ znum = znum**(S.One/n)*exp(I*branch / n)
680
+
681
+ # Convert all args to mpf or mpc
682
+ try:
683
+ [z, r, ap, bq] = [arg._to_mpmath(prec)
684
+ for arg in [znum, 1/n, self.args[0], self.args[1]]]
685
+ except ValueError:
686
+ return
687
+
688
+ with mpmath.workprec(prec):
689
+ v = mpmath.meijerg(ap, bq, z, r)
690
+
691
+ return Expr._from_mpmath(v, prec)
692
+
693
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
694
+ from sympy.simplify.hyperexpand import hyperexpand
695
+ return hyperexpand(self).as_leading_term(x, logx=logx, cdir=cdir)
696
+
697
+ def integrand(self, s):
698
+ """ Get the defining integrand D(s). """
699
+ from sympy.functions.special.gamma_functions import gamma
700
+ return self.argument**s \
701
+ * Mul(*(gamma(b - s) for b in self.bm)) \
702
+ * Mul(*(gamma(1 - a + s) for a in self.an)) \
703
+ / Mul(*(gamma(1 - b + s) for b in self.bother)) \
704
+ / Mul(*(gamma(a - s) for a in self.aother))
705
+
706
+ @property
707
+ def argument(self):
708
+ """ Argument of the Meijer G-function. """
709
+ return self.args[2]
710
+
711
+ @property
712
+ def an(self):
713
+ """ First set of numerator parameters. """
714
+ return Tuple(*self.args[0][0])
715
+
716
+ @property
717
+ def ap(self):
718
+ """ Combined numerator parameters. """
719
+ return Tuple(*(self.args[0][0] + self.args[0][1]))
720
+
721
+ @property
722
+ def aother(self):
723
+ """ Second set of numerator parameters. """
724
+ return Tuple(*self.args[0][1])
725
+
726
+ @property
727
+ def bm(self):
728
+ """ First set of denominator parameters. """
729
+ return Tuple(*self.args[1][0])
730
+
731
+ @property
732
+ def bq(self):
733
+ """ Combined denominator parameters. """
734
+ return Tuple(*(self.args[1][0] + self.args[1][1]))
735
+
736
+ @property
737
+ def bother(self):
738
+ """ Second set of denominator parameters. """
739
+ return Tuple(*self.args[1][1])
740
+
741
+ @property
742
+ def _diffargs(self):
743
+ return self.ap + self.bq
744
+
745
+ @property
746
+ def nu(self):
747
+ """ A quantity related to the convergence region of the integral,
748
+ c.f. references. """
749
+ return sum(self.bq) - sum(self.ap)
750
+
751
+ @property
752
+ def delta(self):
753
+ """ A quantity related to the convergence region of the integral,
754
+ c.f. references. """
755
+ return len(self.bm) + len(self.an) - S(len(self.ap) + len(self.bq))/2
756
+
757
+ @property
758
+ def is_number(self):
759
+ """ Returns true if expression has numeric data only. """
760
+ return not self.free_symbols
761
+
762
+
763
+ class HyperRep(Function):
764
+ """
765
+ A base class for "hyper representation functions".
766
+
767
+ This is used exclusively in ``hyperexpand()``, but fits more logically here.
768
+
769
+ pFq is branched at 1 if p == q+1. For use with slater-expansion, we want
770
+ define an "analytic continuation" to all polar numbers, which is
771
+ continuous on circles and on the ray t*exp_polar(I*pi). Moreover, we want
772
+ a "nice" expression for the various cases.
773
+
774
+ This base class contains the core logic, concrete derived classes only
775
+ supply the actual functions.
776
+
777
+ """
778
+
779
+
780
+ @classmethod
781
+ def eval(cls, *args):
782
+ newargs = tuple(map(unpolarify, args[:-1])) + args[-1:]
783
+ if args != newargs:
784
+ return cls(*newargs)
785
+
786
+ @classmethod
787
+ def _expr_small(cls, x):
788
+ """ An expression for F(x) which holds for |x| < 1. """
789
+ raise NotImplementedError
790
+
791
+ @classmethod
792
+ def _expr_small_minus(cls, x):
793
+ """ An expression for F(-x) which holds for |x| < 1. """
794
+ raise NotImplementedError
795
+
796
+ @classmethod
797
+ def _expr_big(cls, x, n):
798
+ """ An expression for F(exp_polar(2*I*pi*n)*x), |x| > 1. """
799
+ raise NotImplementedError
800
+
801
+ @classmethod
802
+ def _expr_big_minus(cls, x, n):
803
+ """ An expression for F(exp_polar(2*I*pi*n + pi*I)*x), |x| > 1. """
804
+ raise NotImplementedError
805
+
806
+ def _eval_rewrite_as_nonrep(self, *args, **kwargs):
807
+ x, n = self.args[-1].extract_branch_factor(allow_half=True)
808
+ minus = False
809
+ newargs = self.args[:-1] + (x,)
810
+ if not n.is_Integer:
811
+ minus = True
812
+ n -= S.Half
813
+ newerargs = newargs + (n,)
814
+ if minus:
815
+ small = self._expr_small_minus(*newargs)
816
+ big = self._expr_big_minus(*newerargs)
817
+ else:
818
+ small = self._expr_small(*newargs)
819
+ big = self._expr_big(*newerargs)
820
+
821
+ if big == small:
822
+ return small
823
+ return Piecewise((big, abs(x) > 1), (small, True))
824
+
825
+ def _eval_rewrite_as_nonrepsmall(self, *args, **kwargs):
826
+ x, n = self.args[-1].extract_branch_factor(allow_half=True)
827
+ args = self.args[:-1] + (x,)
828
+ if not n.is_Integer:
829
+ return self._expr_small_minus(*args)
830
+ return self._expr_small(*args)
831
+
832
+
833
+ class HyperRep_power1(HyperRep):
834
+ """ Return a representative for hyper([-a], [], z) == (1 - z)**a. """
835
+
836
+ @classmethod
837
+ def _expr_small(cls, a, x):
838
+ return (1 - x)**a
839
+
840
+ @classmethod
841
+ def _expr_small_minus(cls, a, x):
842
+ return (1 + x)**a
843
+
844
+ @classmethod
845
+ def _expr_big(cls, a, x, n):
846
+ if a.is_integer:
847
+ return cls._expr_small(a, x)
848
+ return (x - 1)**a*exp((2*n - 1)*pi*I*a)
849
+
850
+ @classmethod
851
+ def _expr_big_minus(cls, a, x, n):
852
+ if a.is_integer:
853
+ return cls._expr_small_minus(a, x)
854
+ return (1 + x)**a*exp(2*n*pi*I*a)
855
+
856
+
857
+ class HyperRep_power2(HyperRep):
858
+ """ Return a representative for hyper([a, a - 1/2], [2*a], z). """
859
+
860
+ @classmethod
861
+ def _expr_small(cls, a, x):
862
+ return 2**(2*a - 1)*(1 + sqrt(1 - x))**(1 - 2*a)
863
+
864
+ @classmethod
865
+ def _expr_small_minus(cls, a, x):
866
+ return 2**(2*a - 1)*(1 + sqrt(1 + x))**(1 - 2*a)
867
+
868
+ @classmethod
869
+ def _expr_big(cls, a, x, n):
870
+ sgn = -1
871
+ if n.is_odd:
872
+ sgn = 1
873
+ n -= 1
874
+ return 2**(2*a - 1)*(1 + sgn*I*sqrt(x - 1))**(1 - 2*a) \
875
+ *exp(-2*n*pi*I*a)
876
+
877
+ @classmethod
878
+ def _expr_big_minus(cls, a, x, n):
879
+ sgn = 1
880
+ if n.is_odd:
881
+ sgn = -1
882
+ return sgn*2**(2*a - 1)*(sqrt(1 + x) + sgn)**(1 - 2*a)*exp(-2*pi*I*a*n)
883
+
884
+
885
+ class HyperRep_log1(HyperRep):
886
+ """ Represent -z*hyper([1, 1], [2], z) == log(1 - z). """
887
+ @classmethod
888
+ def _expr_small(cls, x):
889
+ return log(1 - x)
890
+
891
+ @classmethod
892
+ def _expr_small_minus(cls, x):
893
+ return log(1 + x)
894
+
895
+ @classmethod
896
+ def _expr_big(cls, x, n):
897
+ return log(x - 1) + (2*n - 1)*pi*I
898
+
899
+ @classmethod
900
+ def _expr_big_minus(cls, x, n):
901
+ return log(1 + x) + 2*n*pi*I
902
+
903
+
904
+ class HyperRep_atanh(HyperRep):
905
+ """ Represent hyper([1/2, 1], [3/2], z) == atanh(sqrt(z))/sqrt(z). """
906
+ @classmethod
907
+ def _expr_small(cls, x):
908
+ return atanh(sqrt(x))/sqrt(x)
909
+
910
+ def _expr_small_minus(cls, x):
911
+ return atan(sqrt(x))/sqrt(x)
912
+
913
+ def _expr_big(cls, x, n):
914
+ if n.is_even:
915
+ return (acoth(sqrt(x)) + I*pi/2)/sqrt(x)
916
+ else:
917
+ return (acoth(sqrt(x)) - I*pi/2)/sqrt(x)
918
+
919
+ def _expr_big_minus(cls, x, n):
920
+ if n.is_even:
921
+ return atan(sqrt(x))/sqrt(x)
922
+ else:
923
+ return (atan(sqrt(x)) - pi)/sqrt(x)
924
+
925
+
926
+ class HyperRep_asin1(HyperRep):
927
+ """ Represent hyper([1/2, 1/2], [3/2], z) == asin(sqrt(z))/sqrt(z). """
928
+ @classmethod
929
+ def _expr_small(cls, z):
930
+ return asin(sqrt(z))/sqrt(z)
931
+
932
+ @classmethod
933
+ def _expr_small_minus(cls, z):
934
+ return asinh(sqrt(z))/sqrt(z)
935
+
936
+ @classmethod
937
+ def _expr_big(cls, z, n):
938
+ return S.NegativeOne**n*((S.Half - n)*pi/sqrt(z) + I*acosh(sqrt(z))/sqrt(z))
939
+
940
+ @classmethod
941
+ def _expr_big_minus(cls, z, n):
942
+ return S.NegativeOne**n*(asinh(sqrt(z))/sqrt(z) + n*pi*I/sqrt(z))
943
+
944
+
945
+ class HyperRep_asin2(HyperRep):
946
+ """ Represent hyper([1, 1], [3/2], z) == asin(sqrt(z))/sqrt(z)/sqrt(1-z). """
947
+ # TODO this can be nicer
948
+ @classmethod
949
+ def _expr_small(cls, z):
950
+ return HyperRep_asin1._expr_small(z) \
951
+ /HyperRep_power1._expr_small(S.Half, z)
952
+
953
+ @classmethod
954
+ def _expr_small_minus(cls, z):
955
+ return HyperRep_asin1._expr_small_minus(z) \
956
+ /HyperRep_power1._expr_small_minus(S.Half, z)
957
+
958
+ @classmethod
959
+ def _expr_big(cls, z, n):
960
+ return HyperRep_asin1._expr_big(z, n) \
961
+ /HyperRep_power1._expr_big(S.Half, z, n)
962
+
963
+ @classmethod
964
+ def _expr_big_minus(cls, z, n):
965
+ return HyperRep_asin1._expr_big_minus(z, n) \
966
+ /HyperRep_power1._expr_big_minus(S.Half, z, n)
967
+
968
+
969
+ class HyperRep_sqrts1(HyperRep):
970
+ """ Return a representative for hyper([-a, 1/2 - a], [1/2], z). """
971
+
972
+ @classmethod
973
+ def _expr_small(cls, a, z):
974
+ return ((1 - sqrt(z))**(2*a) + (1 + sqrt(z))**(2*a))/2
975
+
976
+ @classmethod
977
+ def _expr_small_minus(cls, a, z):
978
+ return (1 + z)**a*cos(2*a*atan(sqrt(z)))
979
+
980
+ @classmethod
981
+ def _expr_big(cls, a, z, n):
982
+ if n.is_even:
983
+ return ((sqrt(z) + 1)**(2*a)*exp(2*pi*I*n*a) +
984
+ (sqrt(z) - 1)**(2*a)*exp(2*pi*I*(n - 1)*a))/2
985
+ else:
986
+ n -= 1
987
+ return ((sqrt(z) - 1)**(2*a)*exp(2*pi*I*a*(n + 1)) +
988
+ (sqrt(z) + 1)**(2*a)*exp(2*pi*I*a*n))/2
989
+
990
+ @classmethod
991
+ def _expr_big_minus(cls, a, z, n):
992
+ if n.is_even:
993
+ return (1 + z)**a*exp(2*pi*I*n*a)*cos(2*a*atan(sqrt(z)))
994
+ else:
995
+ return (1 + z)**a*exp(2*pi*I*n*a)*cos(2*a*atan(sqrt(z)) - 2*pi*a)
996
+
997
+
998
+ class HyperRep_sqrts2(HyperRep):
999
+ """ Return a representative for
1000
+ sqrt(z)/2*[(1-sqrt(z))**2a - (1 + sqrt(z))**2a]
1001
+ == -2*z/(2*a+1) d/dz hyper([-a - 1/2, -a], [1/2], z)"""
1002
+
1003
+ @classmethod
1004
+ def _expr_small(cls, a, z):
1005
+ return sqrt(z)*((1 - sqrt(z))**(2*a) - (1 + sqrt(z))**(2*a))/2
1006
+
1007
+ @classmethod
1008
+ def _expr_small_minus(cls, a, z):
1009
+ return sqrt(z)*(1 + z)**a*sin(2*a*atan(sqrt(z)))
1010
+
1011
+ @classmethod
1012
+ def _expr_big(cls, a, z, n):
1013
+ if n.is_even:
1014
+ return sqrt(z)/2*((sqrt(z) - 1)**(2*a)*exp(2*pi*I*a*(n - 1)) -
1015
+ (sqrt(z) + 1)**(2*a)*exp(2*pi*I*a*n))
1016
+ else:
1017
+ n -= 1
1018
+ return sqrt(z)/2*((sqrt(z) - 1)**(2*a)*exp(2*pi*I*a*(n + 1)) -
1019
+ (sqrt(z) + 1)**(2*a)*exp(2*pi*I*a*n))
1020
+
1021
+ def _expr_big_minus(cls, a, z, n):
1022
+ if n.is_even:
1023
+ return (1 + z)**a*exp(2*pi*I*n*a)*sqrt(z)*sin(2*a*atan(sqrt(z)))
1024
+ else:
1025
+ return (1 + z)**a*exp(2*pi*I*n*a)*sqrt(z) \
1026
+ *sin(2*a*atan(sqrt(z)) - 2*pi*a)
1027
+
1028
+
1029
+ class HyperRep_log2(HyperRep):
1030
+ """ Represent log(1/2 + sqrt(1 - z)/2) == -z/4*hyper([3/2, 1, 1], [2, 2], z) """
1031
+
1032
+ @classmethod
1033
+ def _expr_small(cls, z):
1034
+ return log(S.Half + sqrt(1 - z)/2)
1035
+
1036
+ @classmethod
1037
+ def _expr_small_minus(cls, z):
1038
+ return log(S.Half + sqrt(1 + z)/2)
1039
+
1040
+ @classmethod
1041
+ def _expr_big(cls, z, n):
1042
+ if n.is_even:
1043
+ return (n - S.Half)*pi*I + log(sqrt(z)/2) + I*asin(1/sqrt(z))
1044
+ else:
1045
+ return (n - S.Half)*pi*I + log(sqrt(z)/2) - I*asin(1/sqrt(z))
1046
+
1047
+ def _expr_big_minus(cls, z, n):
1048
+ if n.is_even:
1049
+ return pi*I*n + log(S.Half + sqrt(1 + z)/2)
1050
+ else:
1051
+ return pi*I*n + log(sqrt(1 + z)/2 - S.Half)
1052
+
1053
+
1054
+ class HyperRep_cosasin(HyperRep):
1055
+ """ Represent hyper([a, -a], [1/2], z) == cos(2*a*asin(sqrt(z))). """
1056
+ # Note there are many alternative expressions, e.g. as powers of a sum of
1057
+ # square roots.
1058
+
1059
+ @classmethod
1060
+ def _expr_small(cls, a, z):
1061
+ return cos(2*a*asin(sqrt(z)))
1062
+
1063
+ @classmethod
1064
+ def _expr_small_minus(cls, a, z):
1065
+ return cosh(2*a*asinh(sqrt(z)))
1066
+
1067
+ @classmethod
1068
+ def _expr_big(cls, a, z, n):
1069
+ return cosh(2*a*acosh(sqrt(z)) + a*pi*I*(2*n - 1))
1070
+
1071
+ @classmethod
1072
+ def _expr_big_minus(cls, a, z, n):
1073
+ return cosh(2*a*asinh(sqrt(z)) + 2*a*pi*I*n)
1074
+
1075
+
1076
+ class HyperRep_sinasin(HyperRep):
1077
+ """ Represent 2*a*z*hyper([1 - a, 1 + a], [3/2], z)
1078
+ == sqrt(z)/sqrt(1-z)*sin(2*a*asin(sqrt(z))) """
1079
+
1080
+ @classmethod
1081
+ def _expr_small(cls, a, z):
1082
+ return sqrt(z)/sqrt(1 - z)*sin(2*a*asin(sqrt(z)))
1083
+
1084
+ @classmethod
1085
+ def _expr_small_minus(cls, a, z):
1086
+ return -sqrt(z)/sqrt(1 + z)*sinh(2*a*asinh(sqrt(z)))
1087
+
1088
+ @classmethod
1089
+ def _expr_big(cls, a, z, n):
1090
+ return -1/sqrt(1 - 1/z)*sinh(2*a*acosh(sqrt(z)) + a*pi*I*(2*n - 1))
1091
+
1092
+ @classmethod
1093
+ def _expr_big_minus(cls, a, z, n):
1094
+ return -1/sqrt(1 + 1/z)*sinh(2*a*asinh(sqrt(z)) + 2*a*pi*I*n)
1095
+
1096
+ class appellf1(Function):
1097
+ r"""
1098
+ This is the Appell hypergeometric function of two variables as:
1099
+
1100
+ .. math ::
1101
+ F_1(a,b_1,b_2,c,x,y) = \sum_{m=0}^{\infty} \sum_{n=0}^{\infty}
1102
+ \frac{(a)_{m+n} (b_1)_m (b_2)_n}{(c)_{m+n}}
1103
+ \frac{x^m y^n}{m! n!}.
1104
+
1105
+ Examples
1106
+ ========
1107
+
1108
+ >>> from sympy import appellf1, symbols
1109
+ >>> x, y, a, b1, b2, c = symbols('x y a b1 b2 c')
1110
+ >>> appellf1(2., 1., 6., 4., 5., 6.)
1111
+ 0.0063339426292673
1112
+ >>> appellf1(12., 12., 6., 4., 0.5, 0.12)
1113
+ 172870711.659936
1114
+ >>> appellf1(40, 2, 6, 4, 15, 60)
1115
+ appellf1(40, 2, 6, 4, 15, 60)
1116
+ >>> appellf1(20., 12., 10., 3., 0.5, 0.12)
1117
+ 15605338197184.4
1118
+ >>> appellf1(40, 2, 6, 4, x, y)
1119
+ appellf1(40, 2, 6, 4, x, y)
1120
+ >>> appellf1(a, b1, b2, c, x, y)
1121
+ appellf1(a, b1, b2, c, x, y)
1122
+
1123
+ References
1124
+ ==========
1125
+
1126
+ .. [1] https://en.wikipedia.org/wiki/Appell_series
1127
+ .. [2] https://functions.wolfram.com/HypergeometricFunctions/AppellF1/
1128
+
1129
+ """
1130
+
1131
+ @classmethod
1132
+ def eval(cls, a, b1, b2, c, x, y):
1133
+ if default_sort_key(b1) > default_sort_key(b2):
1134
+ b1, b2 = b2, b1
1135
+ x, y = y, x
1136
+ return cls(a, b1, b2, c, x, y)
1137
+ elif b1 == b2 and default_sort_key(x) > default_sort_key(y):
1138
+ x, y = y, x
1139
+ return cls(a, b1, b2, c, x, y)
1140
+ if x == 0 and y == 0:
1141
+ return S.One
1142
+
1143
+ def fdiff(self, argindex=5):
1144
+ a, b1, b2, c, x, y = self.args
1145
+ if argindex == 5:
1146
+ return (a*b1/c)*appellf1(a + 1, b1 + 1, b2, c + 1, x, y)
1147
+ elif argindex == 6:
1148
+ return (a*b2/c)*appellf1(a + 1, b1, b2 + 1, c + 1, x, y)
1149
+ elif argindex in (1, 2, 3, 4):
1150
+ return Derivative(self, self.args[argindex-1])
1151
+ else:
1152
+ raise ArgumentIndexError(self, argindex)
env-llmeval/lib/python3.10/site-packages/sympy/functions/special/singularity_functions.py ADDED
@@ -0,0 +1,228 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ from sympy.core import S, oo, diff
2
+ from sympy.core.function import Function, ArgumentIndexError
3
+ from sympy.core.logic import fuzzy_not
4
+ from sympy.core.relational import Eq
5
+ from sympy.functions.elementary.complexes import im
6
+ from sympy.functions.elementary.piecewise import Piecewise
7
+ from sympy.functions.special.delta_functions import Heaviside
8
+
9
+ ###############################################################################
10
+ ############################# SINGULARITY FUNCTION ############################
11
+ ###############################################################################
12
+
13
+
14
+ class SingularityFunction(Function):
15
+ r"""
16
+ Singularity functions are a class of discontinuous functions.
17
+
18
+ Explanation
19
+ ===========
20
+
21
+ Singularity functions take a variable, an offset, and an exponent as
22
+ arguments. These functions are represented using Macaulay brackets as:
23
+
24
+ SingularityFunction(x, a, n) := <x - a>^n
25
+
26
+ The singularity function will automatically evaluate to
27
+ ``Derivative(DiracDelta(x - a), x, -n - 1)`` if ``n < 0``
28
+ and ``(x - a)**n*Heaviside(x - a)`` if ``n >= 0``.
29
+
30
+ Examples
31
+ ========
32
+
33
+ >>> from sympy import SingularityFunction, diff, Piecewise, DiracDelta, Heaviside, Symbol
34
+ >>> from sympy.abc import x, a, n
35
+ >>> SingularityFunction(x, a, n)
36
+ SingularityFunction(x, a, n)
37
+ >>> y = Symbol('y', positive=True)
38
+ >>> n = Symbol('n', nonnegative=True)
39
+ >>> SingularityFunction(y, -10, n)
40
+ (y + 10)**n
41
+ >>> y = Symbol('y', negative=True)
42
+ >>> SingularityFunction(y, 10, n)
43
+ 0
44
+ >>> SingularityFunction(x, 4, -1).subs(x, 4)
45
+ oo
46
+ >>> SingularityFunction(x, 10, -2).subs(x, 10)
47
+ oo
48
+ >>> SingularityFunction(4, 1, 5)
49
+ 243
50
+ >>> diff(SingularityFunction(x, 1, 5) + SingularityFunction(x, 1, 4), x)
51
+ 4*SingularityFunction(x, 1, 3) + 5*SingularityFunction(x, 1, 4)
52
+ >>> diff(SingularityFunction(x, 4, 0), x, 2)
53
+ SingularityFunction(x, 4, -2)
54
+ >>> SingularityFunction(x, 4, 5).rewrite(Piecewise)
55
+ Piecewise(((x - 4)**5, x > 4), (0, True))
56
+ >>> expr = SingularityFunction(x, a, n)
57
+ >>> y = Symbol('y', positive=True)
58
+ >>> n = Symbol('n', nonnegative=True)
59
+ >>> expr.subs({x: y, a: -10, n: n})
60
+ (y + 10)**n
61
+
62
+ The methods ``rewrite(DiracDelta)``, ``rewrite(Heaviside)``, and
63
+ ``rewrite('HeavisideDiracDelta')`` returns the same output. One can use any
64
+ of these methods according to their choice.
65
+
66
+ >>> expr = SingularityFunction(x, 4, 5) + SingularityFunction(x, -3, -1) - SingularityFunction(x, 0, -2)
67
+ >>> expr.rewrite(Heaviside)
68
+ (x - 4)**5*Heaviside(x - 4) + DiracDelta(x + 3) - DiracDelta(x, 1)
69
+ >>> expr.rewrite(DiracDelta)
70
+ (x - 4)**5*Heaviside(x - 4) + DiracDelta(x + 3) - DiracDelta(x, 1)
71
+ >>> expr.rewrite('HeavisideDiracDelta')
72
+ (x - 4)**5*Heaviside(x - 4) + DiracDelta(x + 3) - DiracDelta(x, 1)
73
+
74
+ See Also
75
+ ========
76
+
77
+ DiracDelta, Heaviside
78
+
79
+ References
80
+ ==========
81
+
82
+ .. [1] https://en.wikipedia.org/wiki/Singularity_function
83
+
84
+ """
85
+
86
+ is_real = True
87
+
88
+ def fdiff(self, argindex=1):
89
+ """
90
+ Returns the first derivative of a DiracDelta Function.
91
+
92
+ Explanation
93
+ ===========
94
+
95
+ The difference between ``diff()`` and ``fdiff()`` is: ``diff()`` is the
96
+ user-level function and ``fdiff()`` is an object method. ``fdiff()`` is
97
+ a convenience method available in the ``Function`` class. It returns
98
+ the derivative of the function without considering the chain rule.
99
+ ``diff(function, x)`` calls ``Function._eval_derivative`` which in turn
100
+ calls ``fdiff()`` internally to compute the derivative of the function.
101
+
102
+ """
103
+
104
+ if argindex == 1:
105
+ x, a, n = self.args
106
+ if n in (S.Zero, S.NegativeOne):
107
+ return self.func(x, a, n-1)
108
+ elif n.is_positive:
109
+ return n*self.func(x, a, n-1)
110
+ else:
111
+ raise ArgumentIndexError(self, argindex)
112
+
113
+ @classmethod
114
+ def eval(cls, variable, offset, exponent):
115
+ """
116
+ Returns a simplified form or a value of Singularity Function depending
117
+ on the argument passed by the object.
118
+
119
+ Explanation
120
+ ===========
121
+
122
+ The ``eval()`` method is automatically called when the
123
+ ``SingularityFunction`` class is about to be instantiated and it
124
+ returns either some simplified instance or the unevaluated instance
125
+ depending on the argument passed. In other words, ``eval()`` method is
126
+ not needed to be called explicitly, it is being called and evaluated
127
+ once the object is called.
128
+
129
+ Examples
130
+ ========
131
+
132
+ >>> from sympy import SingularityFunction, Symbol, nan
133
+ >>> from sympy.abc import x, a, n
134
+ >>> SingularityFunction(x, a, n)
135
+ SingularityFunction(x, a, n)
136
+ >>> SingularityFunction(5, 3, 2)
137
+ 4
138
+ >>> SingularityFunction(x, a, nan)
139
+ nan
140
+ >>> SingularityFunction(x, 3, 0).subs(x, 3)
141
+ 1
142
+ >>> SingularityFunction(4, 1, 5)
143
+ 243
144
+ >>> x = Symbol('x', positive = True)
145
+ >>> a = Symbol('a', negative = True)
146
+ >>> n = Symbol('n', nonnegative = True)
147
+ >>> SingularityFunction(x, a, n)
148
+ (-a + x)**n
149
+ >>> x = Symbol('x', negative = True)
150
+ >>> a = Symbol('a', positive = True)
151
+ >>> SingularityFunction(x, a, n)
152
+ 0
153
+
154
+ """
155
+
156
+ x = variable
157
+ a = offset
158
+ n = exponent
159
+ shift = (x - a)
160
+
161
+ if fuzzy_not(im(shift).is_zero):
162
+ raise ValueError("Singularity Functions are defined only for Real Numbers.")
163
+ if fuzzy_not(im(n).is_zero):
164
+ raise ValueError("Singularity Functions are not defined for imaginary exponents.")
165
+ if shift is S.NaN or n is S.NaN:
166
+ return S.NaN
167
+ if (n + 2).is_negative:
168
+ raise ValueError("Singularity Functions are not defined for exponents less than -2.")
169
+ if shift.is_extended_negative:
170
+ return S.Zero
171
+ if n.is_nonnegative and shift.is_extended_nonnegative:
172
+ return (x - a)**n
173
+ if n in (S.NegativeOne, -2):
174
+ if shift.is_negative or shift.is_extended_positive:
175
+ return S.Zero
176
+ if shift.is_zero:
177
+ return oo
178
+
179
+ def _eval_rewrite_as_Piecewise(self, *args, **kwargs):
180
+ '''
181
+ Converts a Singularity Function expression into its Piecewise form.
182
+
183
+ '''
184
+ x, a, n = self.args
185
+
186
+ if n in (S.NegativeOne, S(-2)):
187
+ return Piecewise((oo, Eq((x - a), 0)), (0, True))
188
+ elif n.is_nonnegative:
189
+ return Piecewise(((x - a)**n, (x - a) > 0), (0, True))
190
+
191
+ def _eval_rewrite_as_Heaviside(self, *args, **kwargs):
192
+ '''
193
+ Rewrites a Singularity Function expression using Heavisides and DiracDeltas.
194
+
195
+ '''
196
+ x, a, n = self.args
197
+
198
+ if n == -2:
199
+ return diff(Heaviside(x - a), x.free_symbols.pop(), 2)
200
+ if n == -1:
201
+ return diff(Heaviside(x - a), x.free_symbols.pop(), 1)
202
+ if n.is_nonnegative:
203
+ return (x - a)**n*Heaviside(x - a)
204
+
205
+ def _eval_as_leading_term(self, x, logx=None, cdir=0):
206
+ z, a, n = self.args
207
+ shift = (z - a).subs(x, 0)
208
+ if n < 0:
209
+ return S.Zero
210
+ elif n.is_zero and shift.is_zero:
211
+ return S.Zero if cdir == -1 else S.One
212
+ elif shift.is_positive:
213
+ return shift**n
214
+ return S.Zero
215
+
216
+ def _eval_nseries(self, x, n, logx=None, cdir=0):
217
+ z, a, n = self.args
218
+ shift = (z - a).subs(x, 0)
219
+ if n < 0:
220
+ return S.Zero
221
+ elif n.is_zero and shift.is_zero:
222
+ return S.Zero if cdir == -1 else S.One
223
+ elif shift.is_positive:
224
+ return ((z - a)**n)._eval_nseries(x, n, logx=logx, cdir=cdir)
225
+ return S.Zero
226
+
227
+ _eval_rewrite_as_DiracDelta = _eval_rewrite_as_Heaviside
228
+ _eval_rewrite_as_HeavisideDiracDelta = _eval_rewrite_as_Heaviside
env-llmeval/lib/python3.10/site-packages/sympy/functions/special/spherical_harmonics.py ADDED
@@ -0,0 +1,334 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ from sympy.core.expr import Expr
2
+ from sympy.core.function import Function, ArgumentIndexError
3
+ from sympy.core.numbers import I, pi
4
+ from sympy.core.singleton import S
5
+ from sympy.core.symbol import Dummy
6
+ from sympy.functions import assoc_legendre
7
+ from sympy.functions.combinatorial.factorials import factorial
8
+ from sympy.functions.elementary.complexes import Abs, conjugate
9
+ from sympy.functions.elementary.exponential import exp
10
+ from sympy.functions.elementary.miscellaneous import sqrt
11
+ from sympy.functions.elementary.trigonometric import sin, cos, cot
12
+
13
+ _x = Dummy("x")
14
+
15
+ class Ynm(Function):
16
+ r"""
17
+ Spherical harmonics defined as
18
+
19
+ .. math::
20
+ Y_n^m(\theta, \varphi) := \sqrt{\frac{(2n+1)(n-m)!}{4\pi(n+m)!}}
21
+ \exp(i m \varphi)
22
+ \mathrm{P}_n^m\left(\cos(\theta)\right)
23
+
24
+ Explanation
25
+ ===========
26
+
27
+ ``Ynm()`` gives the spherical harmonic function of order $n$ and $m$
28
+ in $\theta$ and $\varphi$, $Y_n^m(\theta, \varphi)$. The four
29
+ parameters are as follows: $n \geq 0$ an integer and $m$ an integer
30
+ such that $-n \leq m \leq n$ holds. The two angles are real-valued
31
+ with $\theta \in [0, \pi]$ and $\varphi \in [0, 2\pi]$.
32
+
33
+ Examples
34
+ ========
35
+
36
+ >>> from sympy import Ynm, Symbol, simplify
37
+ >>> from sympy.abc import n,m
38
+ >>> theta = Symbol("theta")
39
+ >>> phi = Symbol("phi")
40
+
41
+ >>> Ynm(n, m, theta, phi)
42
+ Ynm(n, m, theta, phi)
43
+
44
+ Several symmetries are known, for the order:
45
+
46
+ >>> Ynm(n, -m, theta, phi)
47
+ (-1)**m*exp(-2*I*m*phi)*Ynm(n, m, theta, phi)
48
+
49
+ As well as for the angles:
50
+
51
+ >>> Ynm(n, m, -theta, phi)
52
+ Ynm(n, m, theta, phi)
53
+
54
+ >>> Ynm(n, m, theta, -phi)
55
+ exp(-2*I*m*phi)*Ynm(n, m, theta, phi)
56
+
57
+ For specific integers $n$ and $m$ we can evaluate the harmonics
58
+ to more useful expressions:
59
+
60
+ >>> simplify(Ynm(0, 0, theta, phi).expand(func=True))
61
+ 1/(2*sqrt(pi))
62
+
63
+ >>> simplify(Ynm(1, -1, theta, phi).expand(func=True))
64
+ sqrt(6)*exp(-I*phi)*sin(theta)/(4*sqrt(pi))
65
+
66
+ >>> simplify(Ynm(1, 0, theta, phi).expand(func=True))
67
+ sqrt(3)*cos(theta)/(2*sqrt(pi))
68
+
69
+ >>> simplify(Ynm(1, 1, theta, phi).expand(func=True))
70
+ -sqrt(6)*exp(I*phi)*sin(theta)/(4*sqrt(pi))
71
+
72
+ >>> simplify(Ynm(2, -2, theta, phi).expand(func=True))
73
+ sqrt(30)*exp(-2*I*phi)*sin(theta)**2/(8*sqrt(pi))
74
+
75
+ >>> simplify(Ynm(2, -1, theta, phi).expand(func=True))
76
+ sqrt(30)*exp(-I*phi)*sin(2*theta)/(8*sqrt(pi))
77
+
78
+ >>> simplify(Ynm(2, 0, theta, phi).expand(func=True))
79
+ sqrt(5)*(3*cos(theta)**2 - 1)/(4*sqrt(pi))
80
+
81
+ >>> simplify(Ynm(2, 1, theta, phi).expand(func=True))
82
+ -sqrt(30)*exp(I*phi)*sin(2*theta)/(8*sqrt(pi))
83
+
84
+ >>> simplify(Ynm(2, 2, theta, phi).expand(func=True))
85
+ sqrt(30)*exp(2*I*phi)*sin(theta)**2/(8*sqrt(pi))
86
+
87
+ We can differentiate the functions with respect
88
+ to both angles:
89
+
90
+ >>> from sympy import Ynm, Symbol, diff
91
+ >>> from sympy.abc import n,m
92
+ >>> theta = Symbol("theta")
93
+ >>> phi = Symbol("phi")
94
+
95
+ >>> diff(Ynm(n, m, theta, phi), theta)
96
+ m*cot(theta)*Ynm(n, m, theta, phi) + sqrt((-m + n)*(m + n + 1))*exp(-I*phi)*Ynm(n, m + 1, theta, phi)
97
+
98
+ >>> diff(Ynm(n, m, theta, phi), phi)
99
+ I*m*Ynm(n, m, theta, phi)
100
+
101
+ Further we can compute the complex conjugation:
102
+
103
+ >>> from sympy import Ynm, Symbol, conjugate
104
+ >>> from sympy.abc import n,m
105
+ >>> theta = Symbol("theta")
106
+ >>> phi = Symbol("phi")
107
+
108
+ >>> conjugate(Ynm(n, m, theta, phi))
109
+ (-1)**(2*m)*exp(-2*I*m*phi)*Ynm(n, m, theta, phi)
110
+
111
+ To get back the well known expressions in spherical
112
+ coordinates, we use full expansion:
113
+
114
+ >>> from sympy import Ynm, Symbol, expand_func
115
+ >>> from sympy.abc import n,m
116
+ >>> theta = Symbol("theta")
117
+ >>> phi = Symbol("phi")
118
+
119
+ >>> expand_func(Ynm(n, m, theta, phi))
120
+ sqrt((2*n + 1)*factorial(-m + n)/factorial(m + n))*exp(I*m*phi)*assoc_legendre(n, m, cos(theta))/(2*sqrt(pi))
121
+
122
+ See Also
123
+ ========
124
+
125
+ Ynm_c, Znm
126
+
127
+ References
128
+ ==========
129
+
130
+ .. [1] https://en.wikipedia.org/wiki/Spherical_harmonics
131
+ .. [2] https://mathworld.wolfram.com/SphericalHarmonic.html
132
+ .. [3] https://functions.wolfram.com/Polynomials/SphericalHarmonicY/
133
+ .. [4] https://dlmf.nist.gov/14.30
134
+
135
+ """
136
+
137
+ @classmethod
138
+ def eval(cls, n, m, theta, phi):
139
+ # Handle negative index m and arguments theta, phi
140
+ if m.could_extract_minus_sign():
141
+ m = -m
142
+ return S.NegativeOne**m * exp(-2*I*m*phi) * Ynm(n, m, theta, phi)
143
+ if theta.could_extract_minus_sign():
144
+ theta = -theta
145
+ return Ynm(n, m, theta, phi)
146
+ if phi.could_extract_minus_sign():
147
+ phi = -phi
148
+ return exp(-2*I*m*phi) * Ynm(n, m, theta, phi)
149
+
150
+ # TODO Add more simplififcation here
151
+
152
+ def _eval_expand_func(self, **hints):
153
+ n, m, theta, phi = self.args
154
+ rv = (sqrt((2*n + 1)/(4*pi) * factorial(n - m)/factorial(n + m)) *
155
+ exp(I*m*phi) * assoc_legendre(n, m, cos(theta)))
156
+ # We can do this because of the range of theta
157
+ return rv.subs(sqrt(-cos(theta)**2 + 1), sin(theta))
158
+
159
+ def fdiff(self, argindex=4):
160
+ if argindex == 1:
161
+ # Diff wrt n
162
+ raise ArgumentIndexError(self, argindex)
163
+ elif argindex == 2:
164
+ # Diff wrt m
165
+ raise ArgumentIndexError(self, argindex)
166
+ elif argindex == 3:
167
+ # Diff wrt theta
168
+ n, m, theta, phi = self.args
169
+ return (m * cot(theta) * Ynm(n, m, theta, phi) +
170
+ sqrt((n - m)*(n + m + 1)) * exp(-I*phi) * Ynm(n, m + 1, theta, phi))
171
+ elif argindex == 4:
172
+ # Diff wrt phi
173
+ n, m, theta, phi = self.args
174
+ return I * m * Ynm(n, m, theta, phi)
175
+ else:
176
+ raise ArgumentIndexError(self, argindex)
177
+
178
+ def _eval_rewrite_as_polynomial(self, n, m, theta, phi, **kwargs):
179
+ # TODO: Make sure n \in N
180
+ # TODO: Assert |m| <= n ortherwise we should return 0
181
+ return self.expand(func=True)
182
+
183
+ def _eval_rewrite_as_sin(self, n, m, theta, phi, **kwargs):
184
+ return self.rewrite(cos)
185
+
186
+ def _eval_rewrite_as_cos(self, n, m, theta, phi, **kwargs):
187
+ # This method can be expensive due to extensive use of simplification!
188
+ from sympy.simplify import simplify, trigsimp
189
+ # TODO: Make sure n \in N
190
+ # TODO: Assert |m| <= n ortherwise we should return 0
191
+ term = simplify(self.expand(func=True))
192
+ # We can do this because of the range of theta
193
+ term = term.xreplace({Abs(sin(theta)):sin(theta)})
194
+ return simplify(trigsimp(term))
195
+
196
+ def _eval_conjugate(self):
197
+ # TODO: Make sure theta \in R and phi \in R
198
+ n, m, theta, phi = self.args
199
+ return S.NegativeOne**m * self.func(n, -m, theta, phi)
200
+
201
+ def as_real_imag(self, deep=True, **hints):
202
+ # TODO: Handle deep and hints
203
+ n, m, theta, phi = self.args
204
+ re = (sqrt((2*n + 1)/(4*pi) * factorial(n - m)/factorial(n + m)) *
205
+ cos(m*phi) * assoc_legendre(n, m, cos(theta)))
206
+ im = (sqrt((2*n + 1)/(4*pi) * factorial(n - m)/factorial(n + m)) *
207
+ sin(m*phi) * assoc_legendre(n, m, cos(theta)))
208
+ return (re, im)
209
+
210
+ def _eval_evalf(self, prec):
211
+ # Note: works without this function by just calling
212
+ # mpmath for Legendre polynomials. But using
213
+ # the dedicated function directly is cleaner.
214
+ from mpmath import mp, workprec
215
+ n = self.args[0]._to_mpmath(prec)
216
+ m = self.args[1]._to_mpmath(prec)
217
+ theta = self.args[2]._to_mpmath(prec)
218
+ phi = self.args[3]._to_mpmath(prec)
219
+ with workprec(prec):
220
+ res = mp.spherharm(n, m, theta, phi)
221
+ return Expr._from_mpmath(res, prec)
222
+
223
+
224
+ def Ynm_c(n, m, theta, phi):
225
+ r"""
226
+ Conjugate spherical harmonics defined as
227
+
228
+ .. math::
229
+ \overline{Y_n^m(\theta, \varphi)} := (-1)^m Y_n^{-m}(\theta, \varphi).
230
+
231
+ Examples
232
+ ========
233
+
234
+ >>> from sympy import Ynm_c, Symbol, simplify
235
+ >>> from sympy.abc import n,m
236
+ >>> theta = Symbol("theta")
237
+ >>> phi = Symbol("phi")
238
+ >>> Ynm_c(n, m, theta, phi)
239
+ (-1)**(2*m)*exp(-2*I*m*phi)*Ynm(n, m, theta, phi)
240
+ >>> Ynm_c(n, m, -theta, phi)
241
+ (-1)**(2*m)*exp(-2*I*m*phi)*Ynm(n, m, theta, phi)
242
+
243
+ For specific integers $n$ and $m$ we can evaluate the harmonics
244
+ to more useful expressions:
245
+
246
+ >>> simplify(Ynm_c(0, 0, theta, phi).expand(func=True))
247
+ 1/(2*sqrt(pi))
248
+ >>> simplify(Ynm_c(1, -1, theta, phi).expand(func=True))
249
+ sqrt(6)*exp(I*(-phi + 2*conjugate(phi)))*sin(theta)/(4*sqrt(pi))
250
+
251
+ See Also
252
+ ========
253
+
254
+ Ynm, Znm
255
+
256
+ References
257
+ ==========
258
+
259
+ .. [1] https://en.wikipedia.org/wiki/Spherical_harmonics
260
+ .. [2] https://mathworld.wolfram.com/SphericalHarmonic.html
261
+ .. [3] https://functions.wolfram.com/Polynomials/SphericalHarmonicY/
262
+
263
+ """
264
+ return conjugate(Ynm(n, m, theta, phi))
265
+
266
+
267
+ class Znm(Function):
268
+ r"""
269
+ Real spherical harmonics defined as
270
+
271
+ .. math::
272
+
273
+ Z_n^m(\theta, \varphi) :=
274
+ \begin{cases}
275
+ \frac{Y_n^m(\theta, \varphi) + \overline{Y_n^m(\theta, \varphi)}}{\sqrt{2}} &\quad m > 0 \\
276
+ Y_n^m(\theta, \varphi) &\quad m = 0 \\
277
+ \frac{Y_n^m(\theta, \varphi) - \overline{Y_n^m(\theta, \varphi)}}{i \sqrt{2}} &\quad m < 0 \\
278
+ \end{cases}
279
+
280
+ which gives in simplified form
281
+
282
+ .. math::
283
+
284
+ Z_n^m(\theta, \varphi) =
285
+ \begin{cases}
286
+ \frac{Y_n^m(\theta, \varphi) + (-1)^m Y_n^{-m}(\theta, \varphi)}{\sqrt{2}} &\quad m > 0 \\
287
+ Y_n^m(\theta, \varphi) &\quad m = 0 \\
288
+ \frac{Y_n^m(\theta, \varphi) - (-1)^m Y_n^{-m}(\theta, \varphi)}{i \sqrt{2}} &\quad m < 0 \\
289
+ \end{cases}
290
+
291
+ Examples
292
+ ========
293
+
294
+ >>> from sympy import Znm, Symbol, simplify
295
+ >>> from sympy.abc import n, m
296
+ >>> theta = Symbol("theta")
297
+ >>> phi = Symbol("phi")
298
+ >>> Znm(n, m, theta, phi)
299
+ Znm(n, m, theta, phi)
300
+
301
+ For specific integers n and m we can evaluate the harmonics
302
+ to more useful expressions:
303
+
304
+ >>> simplify(Znm(0, 0, theta, phi).expand(func=True))
305
+ 1/(2*sqrt(pi))
306
+ >>> simplify(Znm(1, 1, theta, phi).expand(func=True))
307
+ -sqrt(3)*sin(theta)*cos(phi)/(2*sqrt(pi))
308
+ >>> simplify(Znm(2, 1, theta, phi).expand(func=True))
309
+ -sqrt(15)*sin(2*theta)*cos(phi)/(4*sqrt(pi))
310
+
311
+ See Also
312
+ ========
313
+
314
+ Ynm, Ynm_c
315
+
316
+ References
317
+ ==========
318
+
319
+ .. [1] https://en.wikipedia.org/wiki/Spherical_harmonics
320
+ .. [2] https://mathworld.wolfram.com/SphericalHarmonic.html
321
+ .. [3] https://functions.wolfram.com/Polynomials/SphericalHarmonicY/
322
+
323
+ """
324
+
325
+ @classmethod
326
+ def eval(cls, n, m, theta, phi):
327
+ if m.is_positive:
328
+ zz = (Ynm(n, m, theta, phi) + Ynm_c(n, m, theta, phi)) / sqrt(2)
329
+ return zz
330
+ elif m.is_zero:
331
+ return Ynm(n, m, theta, phi)
332
+ elif m.is_negative:
333
+ zz = (Ynm(n, m, theta, phi) - Ynm_c(n, m, theta, phi)) / (sqrt(2)*I)
334
+ return zz
env-llmeval/lib/python3.10/site-packages/sympy/functions/special/tensor_functions.py ADDED
@@ -0,0 +1,474 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ from math import prod
2
+
3
+ from sympy.core import S, Integer
4
+ from sympy.core.function import Function
5
+ from sympy.core.logic import fuzzy_not
6
+ from sympy.core.relational import Ne
7
+ from sympy.core.sorting import default_sort_key
8
+ from sympy.external.gmpy import SYMPY_INTS
9
+ from sympy.functions.combinatorial.factorials import factorial
10
+ from sympy.functions.elementary.piecewise import Piecewise
11
+ from sympy.utilities.iterables import has_dups
12
+
13
+ ###############################################################################
14
+ ###################### Kronecker Delta, Levi-Civita etc. ######################
15
+ ###############################################################################
16
+
17
+
18
+ def Eijk(*args, **kwargs):
19
+ """
20
+ Represent the Levi-Civita symbol.
21
+
22
+ This is a compatibility wrapper to ``LeviCivita()``.
23
+
24
+ See Also
25
+ ========
26
+
27
+ LeviCivita
28
+
29
+ """
30
+ return LeviCivita(*args, **kwargs)
31
+
32
+
33
+ def eval_levicivita(*args):
34
+ """Evaluate Levi-Civita symbol."""
35
+ n = len(args)
36
+ return prod(
37
+ prod(args[j] - args[i] for j in range(i + 1, n))
38
+ / factorial(i) for i in range(n))
39
+ # converting factorial(i) to int is slightly faster
40
+
41
+
42
+ class LeviCivita(Function):
43
+ """
44
+ Represent the Levi-Civita symbol.
45
+
46
+ Explanation
47
+ ===========
48
+
49
+ For even permutations of indices it returns 1, for odd permutations -1, and
50
+ for everything else (a repeated index) it returns 0.
51
+
52
+ Thus it represents an alternating pseudotensor.
53
+
54
+ Examples
55
+ ========
56
+
57
+ >>> from sympy import LeviCivita
58
+ >>> from sympy.abc import i, j, k
59
+ >>> LeviCivita(1, 2, 3)
60
+ 1
61
+ >>> LeviCivita(1, 3, 2)
62
+ -1
63
+ >>> LeviCivita(1, 2, 2)
64
+ 0
65
+ >>> LeviCivita(i, j, k)
66
+ LeviCivita(i, j, k)
67
+ >>> LeviCivita(i, j, i)
68
+ 0
69
+
70
+ See Also
71
+ ========
72
+
73
+ Eijk
74
+
75
+ """
76
+
77
+ is_integer = True
78
+
79
+ @classmethod
80
+ def eval(cls, *args):
81
+ if all(isinstance(a, (SYMPY_INTS, Integer)) for a in args):
82
+ return eval_levicivita(*args)
83
+ if has_dups(args):
84
+ return S.Zero
85
+
86
+ def doit(self, **hints):
87
+ return eval_levicivita(*self.args)
88
+
89
+
90
+ class KroneckerDelta(Function):
91
+ """
92
+ The discrete, or Kronecker, delta function.
93
+
94
+ Explanation
95
+ ===========
96
+
97
+ A function that takes in two integers $i$ and $j$. It returns $0$ if $i$
98
+ and $j$ are not equal, or it returns $1$ if $i$ and $j$ are equal.
99
+
100
+ Examples
101
+ ========
102
+
103
+ An example with integer indices:
104
+
105
+ >>> from sympy import KroneckerDelta
106
+ >>> KroneckerDelta(1, 2)
107
+ 0
108
+ >>> KroneckerDelta(3, 3)
109
+ 1
110
+
111
+ Symbolic indices:
112
+
113
+ >>> from sympy.abc import i, j, k
114
+ >>> KroneckerDelta(i, j)
115
+ KroneckerDelta(i, j)
116
+ >>> KroneckerDelta(i, i)
117
+ 1
118
+ >>> KroneckerDelta(i, i + 1)
119
+ 0
120
+ >>> KroneckerDelta(i, i + 1 + k)
121
+ KroneckerDelta(i, i + k + 1)
122
+
123
+ Parameters
124
+ ==========
125
+
126
+ i : Number, Symbol
127
+ The first index of the delta function.
128
+ j : Number, Symbol
129
+ The second index of the delta function.
130
+
131
+ See Also
132
+ ========
133
+
134
+ eval
135
+ DiracDelta
136
+
137
+ References
138
+ ==========
139
+
140
+ .. [1] https://en.wikipedia.org/wiki/Kronecker_delta
141
+
142
+ """
143
+
144
+ is_integer = True
145
+
146
+ @classmethod
147
+ def eval(cls, i, j, delta_range=None):
148
+ """
149
+ Evaluates the discrete delta function.
150
+
151
+ Examples
152
+ ========
153
+
154
+ >>> from sympy import KroneckerDelta
155
+ >>> from sympy.abc import i, j, k
156
+
157
+ >>> KroneckerDelta(i, j)
158
+ KroneckerDelta(i, j)
159
+ >>> KroneckerDelta(i, i)
160
+ 1
161
+ >>> KroneckerDelta(i, i + 1)
162
+ 0
163
+ >>> KroneckerDelta(i, i + 1 + k)
164
+ KroneckerDelta(i, i + k + 1)
165
+
166
+ # indirect doctest
167
+
168
+ """
169
+
170
+ if delta_range is not None:
171
+ dinf, dsup = delta_range
172
+ if (dinf - i > 0) == True:
173
+ return S.Zero
174
+ if (dinf - j > 0) == True:
175
+ return S.Zero
176
+ if (dsup - i < 0) == True:
177
+ return S.Zero
178
+ if (dsup - j < 0) == True:
179
+ return S.Zero
180
+
181
+ diff = i - j
182
+ if diff.is_zero:
183
+ return S.One
184
+ elif fuzzy_not(diff.is_zero):
185
+ return S.Zero
186
+
187
+ if i.assumptions0.get("below_fermi") and \
188
+ j.assumptions0.get("above_fermi"):
189
+ return S.Zero
190
+ if j.assumptions0.get("below_fermi") and \
191
+ i.assumptions0.get("above_fermi"):
192
+ return S.Zero
193
+ # to make KroneckerDelta canonical
194
+ # following lines will check if inputs are in order
195
+ # if not, will return KroneckerDelta with correct order
196
+ if i != min(i, j, key=default_sort_key):
197
+ if delta_range:
198
+ return cls(j, i, delta_range)
199
+ else:
200
+ return cls(j, i)
201
+
202
+ @property
203
+ def delta_range(self):
204
+ if len(self.args) > 2:
205
+ return self.args[2]
206
+
207
+ def _eval_power(self, expt):
208
+ if expt.is_positive:
209
+ return self
210
+ if expt.is_negative and expt is not S.NegativeOne:
211
+ return 1/self
212
+
213
+ @property
214
+ def is_above_fermi(self):
215
+ """
216
+ True if Delta can be non-zero above fermi.
217
+
218
+ Examples
219
+ ========
220
+
221
+ >>> from sympy import KroneckerDelta, Symbol
222
+ >>> a = Symbol('a', above_fermi=True)
223
+ >>> i = Symbol('i', below_fermi=True)
224
+ >>> p = Symbol('p')
225
+ >>> q = Symbol('q')
226
+ >>> KroneckerDelta(p, a).is_above_fermi
227
+ True
228
+ >>> KroneckerDelta(p, i).is_above_fermi
229
+ False
230
+ >>> KroneckerDelta(p, q).is_above_fermi
231
+ True
232
+
233
+ See Also
234
+ ========
235
+
236
+ is_below_fermi, is_only_below_fermi, is_only_above_fermi
237
+
238
+ """
239
+ if self.args[0].assumptions0.get("below_fermi"):
240
+ return False
241
+ if self.args[1].assumptions0.get("below_fermi"):
242
+ return False
243
+ return True
244
+
245
+ @property
246
+ def is_below_fermi(self):
247
+ """
248
+ True if Delta can be non-zero below fermi.
249
+
250
+ Examples
251
+ ========
252
+
253
+ >>> from sympy import KroneckerDelta, Symbol
254
+ >>> a = Symbol('a', above_fermi=True)
255
+ >>> i = Symbol('i', below_fermi=True)
256
+ >>> p = Symbol('p')
257
+ >>> q = Symbol('q')
258
+ >>> KroneckerDelta(p, a).is_below_fermi
259
+ False
260
+ >>> KroneckerDelta(p, i).is_below_fermi
261
+ True
262
+ >>> KroneckerDelta(p, q).is_below_fermi
263
+ True
264
+
265
+ See Also
266
+ ========
267
+
268
+ is_above_fermi, is_only_above_fermi, is_only_below_fermi
269
+
270
+ """
271
+ if self.args[0].assumptions0.get("above_fermi"):
272
+ return False
273
+ if self.args[1].assumptions0.get("above_fermi"):
274
+ return False
275
+ return True
276
+
277
+ @property
278
+ def is_only_above_fermi(self):
279
+ """
280
+ True if Delta is restricted to above fermi.
281
+
282
+ Examples
283
+ ========
284
+
285
+ >>> from sympy import KroneckerDelta, Symbol
286
+ >>> a = Symbol('a', above_fermi=True)
287
+ >>> i = Symbol('i', below_fermi=True)
288
+ >>> p = Symbol('p')
289
+ >>> q = Symbol('q')
290
+ >>> KroneckerDelta(p, a).is_only_above_fermi
291
+ True
292
+ >>> KroneckerDelta(p, q).is_only_above_fermi
293
+ False
294
+ >>> KroneckerDelta(p, i).is_only_above_fermi
295
+ False
296
+
297
+ See Also
298
+ ========
299
+
300
+ is_above_fermi, is_below_fermi, is_only_below_fermi
301
+
302
+ """
303
+ return ( self.args[0].assumptions0.get("above_fermi")
304
+ or
305
+ self.args[1].assumptions0.get("above_fermi")
306
+ ) or False
307
+
308
+ @property
309
+ def is_only_below_fermi(self):
310
+ """
311
+ True if Delta is restricted to below fermi.
312
+
313
+ Examples
314
+ ========
315
+
316
+ >>> from sympy import KroneckerDelta, Symbol
317
+ >>> a = Symbol('a', above_fermi=True)
318
+ >>> i = Symbol('i', below_fermi=True)
319
+ >>> p = Symbol('p')
320
+ >>> q = Symbol('q')
321
+ >>> KroneckerDelta(p, i).is_only_below_fermi
322
+ True
323
+ >>> KroneckerDelta(p, q).is_only_below_fermi
324
+ False
325
+ >>> KroneckerDelta(p, a).is_only_below_fermi
326
+ False
327
+
328
+ See Also
329
+ ========
330
+
331
+ is_above_fermi, is_below_fermi, is_only_above_fermi
332
+
333
+ """
334
+ return ( self.args[0].assumptions0.get("below_fermi")
335
+ or
336
+ self.args[1].assumptions0.get("below_fermi")
337
+ ) or False
338
+
339
+ @property
340
+ def indices_contain_equal_information(self):
341
+ """
342
+ Returns True if indices are either both above or below fermi.
343
+
344
+ Examples
345
+ ========
346
+
347
+ >>> from sympy import KroneckerDelta, Symbol
348
+ >>> a = Symbol('a', above_fermi=True)
349
+ >>> i = Symbol('i', below_fermi=True)
350
+ >>> p = Symbol('p')
351
+ >>> q = Symbol('q')
352
+ >>> KroneckerDelta(p, q).indices_contain_equal_information
353
+ True
354
+ >>> KroneckerDelta(p, q+1).indices_contain_equal_information
355
+ True
356
+ >>> KroneckerDelta(i, p).indices_contain_equal_information
357
+ False
358
+
359
+ """
360
+ if (self.args[0].assumptions0.get("below_fermi") and
361
+ self.args[1].assumptions0.get("below_fermi")):
362
+ return True
363
+ if (self.args[0].assumptions0.get("above_fermi")
364
+ and self.args[1].assumptions0.get("above_fermi")):
365
+ return True
366
+
367
+ # if both indices are general we are True, else false
368
+ return self.is_below_fermi and self.is_above_fermi
369
+
370
+ @property
371
+ def preferred_index(self):
372
+ """
373
+ Returns the index which is preferred to keep in the final expression.
374
+
375
+ Explanation
376
+ ===========
377
+
378
+ The preferred index is the index with more information regarding fermi
379
+ level. If indices contain the same information, 'a' is preferred before
380
+ 'b'.
381
+
382
+ Examples
383
+ ========
384
+
385
+ >>> from sympy import KroneckerDelta, Symbol
386
+ >>> a = Symbol('a', above_fermi=True)
387
+ >>> i = Symbol('i', below_fermi=True)
388
+ >>> j = Symbol('j', below_fermi=True)
389
+ >>> p = Symbol('p')
390
+ >>> KroneckerDelta(p, i).preferred_index
391
+ i
392
+ >>> KroneckerDelta(p, a).preferred_index
393
+ a
394
+ >>> KroneckerDelta(i, j).preferred_index
395
+ i
396
+
397
+ See Also
398
+ ========
399
+
400
+ killable_index
401
+
402
+ """
403
+ if self._get_preferred_index():
404
+ return self.args[1]
405
+ else:
406
+ return self.args[0]
407
+
408
+ @property
409
+ def killable_index(self):
410
+ """
411
+ Returns the index which is preferred to substitute in the final
412
+ expression.
413
+
414
+ Explanation
415
+ ===========
416
+
417
+ The index to substitute is the index with less information regarding
418
+ fermi level. If indices contain the same information, 'a' is preferred
419
+ before 'b'.
420
+
421
+ Examples
422
+ ========
423
+
424
+ >>> from sympy import KroneckerDelta, Symbol
425
+ >>> a = Symbol('a', above_fermi=True)
426
+ >>> i = Symbol('i', below_fermi=True)
427
+ >>> j = Symbol('j', below_fermi=True)
428
+ >>> p = Symbol('p')
429
+ >>> KroneckerDelta(p, i).killable_index
430
+ p
431
+ >>> KroneckerDelta(p, a).killable_index
432
+ p
433
+ >>> KroneckerDelta(i, j).killable_index
434
+ j
435
+
436
+ See Also
437
+ ========
438
+
439
+ preferred_index
440
+
441
+ """
442
+ if self._get_preferred_index():
443
+ return self.args[0]
444
+ else:
445
+ return self.args[1]
446
+
447
+ def _get_preferred_index(self):
448
+ """
449
+ Returns the index which is preferred to keep in the final expression.
450
+
451
+ The preferred index is the index with more information regarding fermi
452
+ level. If indices contain the same information, index 0 is returned.
453
+
454
+ """
455
+ if not self.is_above_fermi:
456
+ if self.args[0].assumptions0.get("below_fermi"):
457
+ return 0
458
+ else:
459
+ return 1
460
+ elif not self.is_below_fermi:
461
+ if self.args[0].assumptions0.get("above_fermi"):
462
+ return 0
463
+ else:
464
+ return 1
465
+ else:
466
+ return 0
467
+
468
+ @property
469
+ def indices(self):
470
+ return self.args[0:2]
471
+
472
+ def _eval_rewrite_as_Piecewise(self, *args, **kwargs):
473
+ i, j = args
474
+ return Piecewise((0, Ne(i, j)), (1, True))
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env-llmeval/lib/python3.10/site-packages/sympy/functions/special/tests/test_beta_functions.py ADDED
@@ -0,0 +1,89 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ from sympy.core.function import (diff, expand_func)
2
+ from sympy.core.numbers import I, Rational, pi
3
+ from sympy.core.singleton import S
4
+ from sympy.core.symbol import (Dummy, symbols)
5
+ from sympy.functions.combinatorial.numbers import catalan
6
+ from sympy.functions.elementary.complexes import conjugate
7
+ from sympy.functions.elementary.miscellaneous import sqrt
8
+ from sympy.functions.special.beta_functions import (beta, betainc, betainc_regularized)
9
+ from sympy.functions.special.gamma_functions import gamma, polygamma
10
+ from sympy.functions.special.hyper import hyper
11
+ from sympy.integrals.integrals import Integral
12
+ from sympy.core.function import ArgumentIndexError
13
+ from sympy.core.expr import unchanged
14
+ from sympy.testing.pytest import raises
15
+
16
+
17
+ def test_beta():
18
+ x, y = symbols('x y')
19
+ t = Dummy('t')
20
+
21
+ assert unchanged(beta, x, y)
22
+ assert unchanged(beta, x, x)
23
+
24
+ assert beta(5, -3).is_real == True
25
+ assert beta(3, y).is_real is None
26
+
27
+ assert expand_func(beta(x, y)) == gamma(x)*gamma(y)/gamma(x + y)
28
+ assert expand_func(beta(x, y) - beta(y, x)) == 0 # Symmetric
29
+ assert expand_func(beta(x, y)) == expand_func(beta(x, y + 1) + beta(x + 1, y)).simplify()
30
+
31
+ assert diff(beta(x, y), x) == beta(x, y)*(polygamma(0, x) - polygamma(0, x + y))
32
+ assert diff(beta(x, y), y) == beta(x, y)*(polygamma(0, y) - polygamma(0, x + y))
33
+
34
+ assert conjugate(beta(x, y)) == beta(conjugate(x), conjugate(y))
35
+
36
+ raises(ArgumentIndexError, lambda: beta(x, y).fdiff(3))
37
+
38
+ assert beta(x, y).rewrite(gamma) == gamma(x)*gamma(y)/gamma(x + y)
39
+ assert beta(x).rewrite(gamma) == gamma(x)**2/gamma(2*x)
40
+ assert beta(x, y).rewrite(Integral).dummy_eq(Integral(t**(x - 1) * (1 - t)**(y - 1), (t, 0, 1)))
41
+ assert beta(Rational(-19, 10), Rational(-1, 10)) == S.Zero
42
+ assert beta(Rational(-19, 10), Rational(-9, 10)) == \
43
+ 800*2**(S(4)/5)*sqrt(pi)*gamma(S.One/10)/(171*gamma(-S(7)/5))
44
+ assert beta(Rational(19, 10), Rational(29, 10)) == 100/(551*catalan(Rational(19, 10)))
45
+ assert beta(1, 0) == S.ComplexInfinity
46
+ assert beta(0, 1) == S.ComplexInfinity
47
+ assert beta(2, 3) == S.One/12
48
+ assert unchanged(beta, x, x + 1)
49
+ assert unchanged(beta, x, 1)
50
+ assert unchanged(beta, 1, y)
51
+ assert beta(x, x + 1).doit() == 1/(x*(x+1)*catalan(x))
52
+ assert beta(1, y).doit() == 1/y
53
+ assert beta(x, 1).doit() == 1/x
54
+ assert beta(Rational(-19, 10), Rational(-1, 10), evaluate=False).doit() == S.Zero
55
+ assert beta(2) == beta(2, 2)
56
+ assert beta(x, evaluate=False) != beta(x, x)
57
+ assert beta(x, evaluate=False).doit() == beta(x, x)
58
+
59
+
60
+ def test_betainc():
61
+ a, b, x1, x2 = symbols('a b x1 x2')
62
+
63
+ assert unchanged(betainc, a, b, x1, x2)
64
+ assert unchanged(betainc, a, b, 0, x1)
65
+
66
+ assert betainc(1, 2, 0, -5).is_real == True
67
+ assert betainc(1, 2, 0, x2).is_real is None
68
+ assert conjugate(betainc(I, 2, 3 - I, 1 + 4*I)) == betainc(-I, 2, 3 + I, 1 - 4*I)
69
+
70
+ assert betainc(a, b, 0, 1).rewrite(Integral).dummy_eq(beta(a, b).rewrite(Integral))
71
+ assert betainc(1, 2, 0, x2).rewrite(hyper) == x2*hyper((1, -1), (2,), x2)
72
+
73
+ assert betainc(1, 2, 3, 3).evalf() == 0
74
+
75
+
76
+ def test_betainc_regularized():
77
+ a, b, x1, x2 = symbols('a b x1 x2')
78
+
79
+ assert unchanged(betainc_regularized, a, b, x1, x2)
80
+ assert unchanged(betainc_regularized, a, b, 0, x1)
81
+
82
+ assert betainc_regularized(3, 5, 0, -1).is_real == True
83
+ assert betainc_regularized(3, 5, 0, x2).is_real is None
84
+ assert conjugate(betainc_regularized(3*I, 1, 2 + I, 1 + 2*I)) == betainc_regularized(-3*I, 1, 2 - I, 1 - 2*I)
85
+
86
+ assert betainc_regularized(a, b, 0, 1).rewrite(Integral) == 1
87
+ assert betainc_regularized(1, 2, x1, x2).rewrite(hyper) == 2*x2*hyper((1, -1), (2,), x2) - 2*x1*hyper((1, -1), (2,), x1)
88
+
89
+ assert betainc_regularized(4, 1, 5, 5).evalf() == 0
env-llmeval/lib/python3.10/site-packages/sympy/functions/special/tests/test_elliptic_integrals.py ADDED
@@ -0,0 +1,179 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ from sympy.core.numbers import (I, Rational, oo, pi, zoo)
2
+ from sympy.core.singleton import S
3
+ from sympy.core.symbol import (Dummy, Symbol)
4
+ from sympy.functions.elementary.hyperbolic import atanh
5
+ from sympy.functions.elementary.miscellaneous import sqrt
6
+ from sympy.functions.elementary.trigonometric import (sin, tan)
7
+ from sympy.functions.special.gamma_functions import gamma
8
+ from sympy.functions.special.hyper import (hyper, meijerg)
9
+ from sympy.integrals.integrals import Integral
10
+ from sympy.series.order import O
11
+ from sympy.functions.special.elliptic_integrals import (elliptic_k as K,
12
+ elliptic_f as F, elliptic_e as E, elliptic_pi as P)
13
+ from sympy.core.random import (test_derivative_numerically as td,
14
+ random_complex_number as randcplx,
15
+ verify_numerically as tn)
16
+ from sympy.abc import z, m, n
17
+
18
+ i = Symbol('i', integer=True)
19
+ j = Symbol('k', integer=True, positive=True)
20
+ t = Dummy('t')
21
+
22
+ def test_K():
23
+ assert K(0) == pi/2
24
+ assert K(S.Half) == 8*pi**Rational(3, 2)/gamma(Rational(-1, 4))**2
25
+ assert K(1) is zoo
26
+ assert K(-1) == gamma(Rational(1, 4))**2/(4*sqrt(2*pi))
27
+ assert K(oo) == 0
28
+ assert K(-oo) == 0
29
+ assert K(I*oo) == 0
30
+ assert K(-I*oo) == 0
31
+ assert K(zoo) == 0
32
+
33
+ assert K(z).diff(z) == (E(z) - (1 - z)*K(z))/(2*z*(1 - z))
34
+ assert td(K(z), z)
35
+
36
+ zi = Symbol('z', real=False)
37
+ assert K(zi).conjugate() == K(zi.conjugate())
38
+ zr = Symbol('z', negative=True)
39
+ assert K(zr).conjugate() == K(zr)
40
+
41
+ assert K(z).rewrite(hyper) == \
42
+ (pi/2)*hyper((S.Half, S.Half), (S.One,), z)
43
+ assert tn(K(z), (pi/2)*hyper((S.Half, S.Half), (S.One,), z))
44
+ assert K(z).rewrite(meijerg) == \
45
+ meijerg(((S.Half, S.Half), []), ((S.Zero,), (S.Zero,)), -z)/2
46
+ assert tn(K(z), meijerg(((S.Half, S.Half), []), ((S.Zero,), (S.Zero,)), -z)/2)
47
+
48
+ assert K(z).series(z) == pi/2 + pi*z/8 + 9*pi*z**2/128 + \
49
+ 25*pi*z**3/512 + 1225*pi*z**4/32768 + 3969*pi*z**5/131072 + O(z**6)
50
+
51
+ assert K(m).rewrite(Integral).dummy_eq(
52
+ Integral(1/sqrt(1 - m*sin(t)**2), (t, 0, pi/2)))
53
+
54
+ def test_F():
55
+ assert F(z, 0) == z
56
+ assert F(0, m) == 0
57
+ assert F(pi*i/2, m) == i*K(m)
58
+ assert F(z, oo) == 0
59
+ assert F(z, -oo) == 0
60
+
61
+ assert F(-z, m) == -F(z, m)
62
+
63
+ assert F(z, m).diff(z) == 1/sqrt(1 - m*sin(z)**2)
64
+ assert F(z, m).diff(m) == E(z, m)/(2*m*(1 - m)) - F(z, m)/(2*m) - \
65
+ sin(2*z)/(4*(1 - m)*sqrt(1 - m*sin(z)**2))
66
+ r = randcplx()
67
+ assert td(F(z, r), z)
68
+ assert td(F(r, m), m)
69
+
70
+ mi = Symbol('m', real=False)
71
+ assert F(z, mi).conjugate() == F(z.conjugate(), mi.conjugate())
72
+ mr = Symbol('m', negative=True)
73
+ assert F(z, mr).conjugate() == F(z.conjugate(), mr)
74
+
75
+ assert F(z, m).series(z) == \
76
+ z + z**5*(3*m**2/40 - m/30) + m*z**3/6 + O(z**6)
77
+
78
+ assert F(z, m).rewrite(Integral).dummy_eq(
79
+ Integral(1/sqrt(1 - m*sin(t)**2), (t, 0, z)))
80
+
81
+ def test_E():
82
+ assert E(z, 0) == z
83
+ assert E(0, m) == 0
84
+ assert E(i*pi/2, m) == i*E(m)
85
+ assert E(z, oo) is zoo
86
+ assert E(z, -oo) is zoo
87
+ assert E(0) == pi/2
88
+ assert E(1) == 1
89
+ assert E(oo) == I*oo
90
+ assert E(-oo) is oo
91
+ assert E(zoo) is zoo
92
+
93
+ assert E(-z, m) == -E(z, m)
94
+
95
+ assert E(z, m).diff(z) == sqrt(1 - m*sin(z)**2)
96
+ assert E(z, m).diff(m) == (E(z, m) - F(z, m))/(2*m)
97
+ assert E(z).diff(z) == (E(z) - K(z))/(2*z)
98
+ r = randcplx()
99
+ assert td(E(r, m), m)
100
+ assert td(E(z, r), z)
101
+ assert td(E(z), z)
102
+
103
+ mi = Symbol('m', real=False)
104
+ assert E(z, mi).conjugate() == E(z.conjugate(), mi.conjugate())
105
+ assert E(mi).conjugate() == E(mi.conjugate())
106
+ mr = Symbol('m', negative=True)
107
+ assert E(z, mr).conjugate() == E(z.conjugate(), mr)
108
+ assert E(mr).conjugate() == E(mr)
109
+
110
+ assert E(z).rewrite(hyper) == (pi/2)*hyper((Rational(-1, 2), S.Half), (S.One,), z)
111
+ assert tn(E(z), (pi/2)*hyper((Rational(-1, 2), S.Half), (S.One,), z))
112
+ assert E(z).rewrite(meijerg) == \
113
+ -meijerg(((S.Half, Rational(3, 2)), []), ((S.Zero,), (S.Zero,)), -z)/4
114
+ assert tn(E(z), -meijerg(((S.Half, Rational(3, 2)), []), ((S.Zero,), (S.Zero,)), -z)/4)
115
+
116
+ assert E(z, m).series(z) == \
117
+ z + z**5*(-m**2/40 + m/30) - m*z**3/6 + O(z**6)
118
+ assert E(z).series(z) == pi/2 - pi*z/8 - 3*pi*z**2/128 - \
119
+ 5*pi*z**3/512 - 175*pi*z**4/32768 - 441*pi*z**5/131072 + O(z**6)
120
+
121
+ assert E(z, m).rewrite(Integral).dummy_eq(
122
+ Integral(sqrt(1 - m*sin(t)**2), (t, 0, z)))
123
+ assert E(m).rewrite(Integral).dummy_eq(
124
+ Integral(sqrt(1 - m*sin(t)**2), (t, 0, pi/2)))
125
+
126
+ def test_P():
127
+ assert P(0, z, m) == F(z, m)
128
+ assert P(1, z, m) == F(z, m) + \
129
+ (sqrt(1 - m*sin(z)**2)*tan(z) - E(z, m))/(1 - m)
130
+ assert P(n, i*pi/2, m) == i*P(n, m)
131
+ assert P(n, z, 0) == atanh(sqrt(n - 1)*tan(z))/sqrt(n - 1)
132
+ assert P(n, z, n) == F(z, n) - P(1, z, n) + tan(z)/sqrt(1 - n*sin(z)**2)
133
+ assert P(oo, z, m) == 0
134
+ assert P(-oo, z, m) == 0
135
+ assert P(n, z, oo) == 0
136
+ assert P(n, z, -oo) == 0
137
+ assert P(0, m) == K(m)
138
+ assert P(1, m) is zoo
139
+ assert P(n, 0) == pi/(2*sqrt(1 - n))
140
+ assert P(2, 1) is -oo
141
+ assert P(-1, 1) is oo
142
+ assert P(n, n) == E(n)/(1 - n)
143
+
144
+ assert P(n, -z, m) == -P(n, z, m)
145
+
146
+ ni, mi = Symbol('n', real=False), Symbol('m', real=False)
147
+ assert P(ni, z, mi).conjugate() == \
148
+ P(ni.conjugate(), z.conjugate(), mi.conjugate())
149
+ nr, mr = Symbol('n', negative=True), \
150
+ Symbol('m', negative=True)
151
+ assert P(nr, z, mr).conjugate() == P(nr, z.conjugate(), mr)
152
+ assert P(n, m).conjugate() == P(n.conjugate(), m.conjugate())
153
+
154
+ assert P(n, z, m).diff(n) == (E(z, m) + (m - n)*F(z, m)/n +
155
+ (n**2 - m)*P(n, z, m)/n - n*sqrt(1 -
156
+ m*sin(z)**2)*sin(2*z)/(2*(1 - n*sin(z)**2)))/(2*(m - n)*(n - 1))
157
+ assert P(n, z, m).diff(z) == 1/(sqrt(1 - m*sin(z)**2)*(1 - n*sin(z)**2))
158
+ assert P(n, z, m).diff(m) == (E(z, m)/(m - 1) + P(n, z, m) -
159
+ m*sin(2*z)/(2*(m - 1)*sqrt(1 - m*sin(z)**2)))/(2*(n - m))
160
+ assert P(n, m).diff(n) == (E(m) + (m - n)*K(m)/n +
161
+ (n**2 - m)*P(n, m)/n)/(2*(m - n)*(n - 1))
162
+ assert P(n, m).diff(m) == (E(m)/(m - 1) + P(n, m))/(2*(n - m))
163
+
164
+ # These tests fail due to
165
+ # https://github.com/fredrik-johansson/mpmath/issues/571#issuecomment-777201962
166
+ # https://github.com/sympy/sympy/issues/20933#issuecomment-777080385
167
+ #
168
+ # rx, ry = randcplx(), randcplx()
169
+ # assert td(P(n, rx, ry), n)
170
+ # assert td(P(rx, z, ry), z)
171
+ # assert td(P(rx, ry, m), m)
172
+
173
+ assert P(n, z, m).series(z) == z + z**3*(m/6 + n/3) + \
174
+ z**5*(3*m**2/40 + m*n/10 - m/30 + n**2/5 - n/15) + O(z**6)
175
+
176
+ assert P(n, z, m).rewrite(Integral).dummy_eq(
177
+ Integral(1/((1 - n*sin(t)**2)*sqrt(1 - m*sin(t)**2)), (t, 0, z)))
178
+ assert P(n, m).rewrite(Integral).dummy_eq(
179
+ Integral(1/((1 - n*sin(t)**2)*sqrt(1 - m*sin(t)**2)), (t, 0, pi/2)))
env-llmeval/lib/python3.10/site-packages/sympy/functions/special/tests/test_spherical_harmonics.py ADDED
@@ -0,0 +1,66 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ from sympy.core.function import diff
2
+ from sympy.core.numbers import (I, pi)
3
+ from sympy.core.symbol import Symbol
4
+ from sympy.functions.elementary.complexes import conjugate
5
+ from sympy.functions.elementary.exponential import exp
6
+ from sympy.functions.elementary.miscellaneous import sqrt
7
+ from sympy.functions.elementary.trigonometric import (cos, cot, sin)
8
+ from sympy.functions.special.spherical_harmonics import Ynm, Znm, Ynm_c
9
+
10
+
11
+ def test_Ynm():
12
+ # https://en.wikipedia.org/wiki/Spherical_harmonics
13
+ th, ph = Symbol("theta", real=True), Symbol("phi", real=True)
14
+ from sympy.abc import n,m
15
+
16
+ assert Ynm(0, 0, th, ph).expand(func=True) == 1/(2*sqrt(pi))
17
+ assert Ynm(1, -1, th, ph) == -exp(-2*I*ph)*Ynm(1, 1, th, ph)
18
+ assert Ynm(1, -1, th, ph).expand(func=True) == sqrt(6)*sin(th)*exp(-I*ph)/(4*sqrt(pi))
19
+ assert Ynm(1, 0, th, ph).expand(func=True) == sqrt(3)*cos(th)/(2*sqrt(pi))
20
+ assert Ynm(1, 1, th, ph).expand(func=True) == -sqrt(6)*sin(th)*exp(I*ph)/(4*sqrt(pi))
21
+ assert Ynm(2, 0, th, ph).expand(func=True) == 3*sqrt(5)*cos(th)**2/(4*sqrt(pi)) - sqrt(5)/(4*sqrt(pi))
22
+ assert Ynm(2, 1, th, ph).expand(func=True) == -sqrt(30)*sin(th)*exp(I*ph)*cos(th)/(4*sqrt(pi))
23
+ assert Ynm(2, -2, th, ph).expand(func=True) == (-sqrt(30)*exp(-2*I*ph)*cos(th)**2/(8*sqrt(pi))
24
+ + sqrt(30)*exp(-2*I*ph)/(8*sqrt(pi)))
25
+ assert Ynm(2, 2, th, ph).expand(func=True) == (-sqrt(30)*exp(2*I*ph)*cos(th)**2/(8*sqrt(pi))
26
+ + sqrt(30)*exp(2*I*ph)/(8*sqrt(pi)))
27
+
28
+ assert diff(Ynm(n, m, th, ph), th) == (m*cot(th)*Ynm(n, m, th, ph)
29
+ + sqrt((-m + n)*(m + n + 1))*exp(-I*ph)*Ynm(n, m + 1, th, ph))
30
+ assert diff(Ynm(n, m, th, ph), ph) == I*m*Ynm(n, m, th, ph)
31
+
32
+ assert conjugate(Ynm(n, m, th, ph)) == (-1)**(2*m)*exp(-2*I*m*ph)*Ynm(n, m, th, ph)
33
+
34
+ assert Ynm(n, m, -th, ph) == Ynm(n, m, th, ph)
35
+ assert Ynm(n, m, th, -ph) == exp(-2*I*m*ph)*Ynm(n, m, th, ph)
36
+ assert Ynm(n, -m, th, ph) == (-1)**m*exp(-2*I*m*ph)*Ynm(n, m, th, ph)
37
+
38
+
39
+ def test_Ynm_c():
40
+ th, ph = Symbol("theta", real=True), Symbol("phi", real=True)
41
+ from sympy.abc import n,m
42
+
43
+ assert Ynm_c(n, m, th, ph) == (-1)**(2*m)*exp(-2*I*m*ph)*Ynm(n, m, th, ph)
44
+
45
+
46
+ def test_Znm():
47
+ # https://en.wikipedia.org/wiki/Solid_harmonics#List_of_lowest_functions
48
+ th, ph = Symbol("theta", real=True), Symbol("phi", real=True)
49
+
50
+ assert Znm(0, 0, th, ph) == Ynm(0, 0, th, ph)
51
+ assert Znm(1, -1, th, ph) == (-sqrt(2)*I*(Ynm(1, 1, th, ph)
52
+ - exp(-2*I*ph)*Ynm(1, 1, th, ph))/2)
53
+ assert Znm(1, 0, th, ph) == Ynm(1, 0, th, ph)
54
+ assert Znm(1, 1, th, ph) == (sqrt(2)*(Ynm(1, 1, th, ph)
55
+ + exp(-2*I*ph)*Ynm(1, 1, th, ph))/2)
56
+ assert Znm(0, 0, th, ph).expand(func=True) == 1/(2*sqrt(pi))
57
+ assert Znm(1, -1, th, ph).expand(func=True) == (sqrt(3)*I*sin(th)*exp(I*ph)/(4*sqrt(pi))
58
+ - sqrt(3)*I*sin(th)*exp(-I*ph)/(4*sqrt(pi)))
59
+ assert Znm(1, 0, th, ph).expand(func=True) == sqrt(3)*cos(th)/(2*sqrt(pi))
60
+ assert Znm(1, 1, th, ph).expand(func=True) == (-sqrt(3)*sin(th)*exp(I*ph)/(4*sqrt(pi))
61
+ - sqrt(3)*sin(th)*exp(-I*ph)/(4*sqrt(pi)))
62
+ assert Znm(2, -1, th, ph).expand(func=True) == (sqrt(15)*I*sin(th)*exp(I*ph)*cos(th)/(4*sqrt(pi))
63
+ - sqrt(15)*I*sin(th)*exp(-I*ph)*cos(th)/(4*sqrt(pi)))
64
+ assert Znm(2, 0, th, ph).expand(func=True) == 3*sqrt(5)*cos(th)**2/(4*sqrt(pi)) - sqrt(5)/(4*sqrt(pi))
65
+ assert Znm(2, 1, th, ph).expand(func=True) == (-sqrt(15)*sin(th)*exp(I*ph)*cos(th)/(4*sqrt(pi))
66
+ - sqrt(15)*sin(th)*exp(-I*ph)*cos(th)/(4*sqrt(pi)))
env-llmeval/lib/python3.10/site-packages/sympy/functions/special/tests/test_tensor_functions.py ADDED
@@ -0,0 +1,145 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ from sympy.core.relational import Ne
2
+ from sympy.core.symbol import (Dummy, Symbol, symbols)
3
+ from sympy.functions.elementary.complexes import (adjoint, conjugate, transpose)
4
+ from sympy.functions.elementary.piecewise import Piecewise
5
+ from sympy.functions.special.tensor_functions import (Eijk, KroneckerDelta, LeviCivita)
6
+
7
+ from sympy.physics.secondquant import evaluate_deltas, F
8
+
9
+ x, y = symbols('x y')
10
+
11
+
12
+ def test_levicivita():
13
+ assert Eijk(1, 2, 3) == LeviCivita(1, 2, 3)
14
+ assert LeviCivita(1, 2, 3) == 1
15
+ assert LeviCivita(int(1), int(2), int(3)) == 1
16
+ assert LeviCivita(1, 3, 2) == -1
17
+ assert LeviCivita(1, 2, 2) == 0
18
+ i, j, k = symbols('i j k')
19
+ assert LeviCivita(i, j, k) == LeviCivita(i, j, k, evaluate=False)
20
+ assert LeviCivita(i, j, i) == 0
21
+ assert LeviCivita(1, i, i) == 0
22
+ assert LeviCivita(i, j, k).doit() == (j - i)*(k - i)*(k - j)/2
23
+ assert LeviCivita(1, 2, 3, 1) == 0
24
+ assert LeviCivita(4, 5, 1, 2, 3) == 1
25
+ assert LeviCivita(4, 5, 2, 1, 3) == -1
26
+
27
+ assert LeviCivita(i, j, k).is_integer is True
28
+
29
+ assert adjoint(LeviCivita(i, j, k)) == LeviCivita(i, j, k)
30
+ assert conjugate(LeviCivita(i, j, k)) == LeviCivita(i, j, k)
31
+ assert transpose(LeviCivita(i, j, k)) == LeviCivita(i, j, k)
32
+
33
+
34
+ def test_kronecker_delta():
35
+ i, j = symbols('i j')
36
+ k = Symbol('k', nonzero=True)
37
+ assert KroneckerDelta(1, 1) == 1
38
+ assert KroneckerDelta(1, 2) == 0
39
+ assert KroneckerDelta(k, 0) == 0
40
+ assert KroneckerDelta(x, x) == 1
41
+ assert KroneckerDelta(x**2 - y**2, x**2 - y**2) == 1
42
+ assert KroneckerDelta(i, i) == 1
43
+ assert KroneckerDelta(i, i + 1) == 0
44
+ assert KroneckerDelta(0, 0) == 1
45
+ assert KroneckerDelta(0, 1) == 0
46
+ assert KroneckerDelta(i + k, i) == 0
47
+ assert KroneckerDelta(i + k, i + k) == 1
48
+ assert KroneckerDelta(i + k, i + 1 + k) == 0
49
+ assert KroneckerDelta(i, j).subs({"i": 1, "j": 0}) == 0
50
+ assert KroneckerDelta(i, j).subs({"i": 3, "j": 3}) == 1
51
+
52
+ assert KroneckerDelta(i, j)**0 == 1
53
+ for n in range(1, 10):
54
+ assert KroneckerDelta(i, j)**n == KroneckerDelta(i, j)
55
+ assert KroneckerDelta(i, j)**-n == 1/KroneckerDelta(i, j)
56
+
57
+ assert KroneckerDelta(i, j).is_integer is True
58
+
59
+ assert adjoint(KroneckerDelta(i, j)) == KroneckerDelta(i, j)
60
+ assert conjugate(KroneckerDelta(i, j)) == KroneckerDelta(i, j)
61
+ assert transpose(KroneckerDelta(i, j)) == KroneckerDelta(i, j)
62
+ # to test if canonical
63
+ assert (KroneckerDelta(i, j) == KroneckerDelta(j, i)) == True
64
+
65
+ assert KroneckerDelta(i, j).rewrite(Piecewise) == Piecewise((0, Ne(i, j)), (1, True))
66
+
67
+ # Tests with range:
68
+ assert KroneckerDelta(i, j, (0, i)).args == (i, j, (0, i))
69
+ assert KroneckerDelta(i, j, (-j, i)).delta_range == (-j, i)
70
+
71
+ # If index is out of range, return zero:
72
+ assert KroneckerDelta(i, j, (0, i-1)) == 0
73
+ assert KroneckerDelta(-1, j, (0, i-1)) == 0
74
+ assert KroneckerDelta(j, -1, (0, i-1)) == 0
75
+ assert KroneckerDelta(j, i, (0, i-1)) == 0
76
+
77
+
78
+ def test_kronecker_delta_secondquant():
79
+ """secondquant-specific methods"""
80
+ D = KroneckerDelta
81
+ i, j, v, w = symbols('i j v w', below_fermi=True, cls=Dummy)
82
+ a, b, t, u = symbols('a b t u', above_fermi=True, cls=Dummy)
83
+ p, q, r, s = symbols('p q r s', cls=Dummy)
84
+
85
+ assert D(i, a) == 0
86
+ assert D(i, t) == 0
87
+
88
+ assert D(i, j).is_above_fermi is False
89
+ assert D(a, b).is_above_fermi is True
90
+ assert D(p, q).is_above_fermi is True
91
+ assert D(i, q).is_above_fermi is False
92
+ assert D(q, i).is_above_fermi is False
93
+ assert D(q, v).is_above_fermi is False
94
+ assert D(a, q).is_above_fermi is True
95
+
96
+ assert D(i, j).is_below_fermi is True
97
+ assert D(a, b).is_below_fermi is False
98
+ assert D(p, q).is_below_fermi is True
99
+ assert D(p, j).is_below_fermi is True
100
+ assert D(q, b).is_below_fermi is False
101
+
102
+ assert D(i, j).is_only_above_fermi is False
103
+ assert D(a, b).is_only_above_fermi is True
104
+ assert D(p, q).is_only_above_fermi is False
105
+ assert D(i, q).is_only_above_fermi is False
106
+ assert D(q, i).is_only_above_fermi is False
107
+ assert D(a, q).is_only_above_fermi is True
108
+
109
+ assert D(i, j).is_only_below_fermi is True
110
+ assert D(a, b).is_only_below_fermi is False
111
+ assert D(p, q).is_only_below_fermi is False
112
+ assert D(p, j).is_only_below_fermi is True
113
+ assert D(q, b).is_only_below_fermi is False
114
+
115
+ assert not D(i, q).indices_contain_equal_information
116
+ assert not D(a, q).indices_contain_equal_information
117
+ assert D(p, q).indices_contain_equal_information
118
+ assert D(a, b).indices_contain_equal_information
119
+ assert D(i, j).indices_contain_equal_information
120
+
121
+ assert D(q, b).preferred_index == b
122
+ assert D(q, b).killable_index == q
123
+ assert D(q, t).preferred_index == t
124
+ assert D(q, t).killable_index == q
125
+ assert D(q, i).preferred_index == i
126
+ assert D(q, i).killable_index == q
127
+ assert D(q, v).preferred_index == v
128
+ assert D(q, v).killable_index == q
129
+ assert D(q, p).preferred_index == p
130
+ assert D(q, p).killable_index == q
131
+
132
+ EV = evaluate_deltas
133
+ assert EV(D(a, q)*F(q)) == F(a)
134
+ assert EV(D(i, q)*F(q)) == F(i)
135
+ assert EV(D(a, q)*F(a)) == D(a, q)*F(a)
136
+ assert EV(D(i, q)*F(i)) == D(i, q)*F(i)
137
+ assert EV(D(a, b)*F(a)) == F(b)
138
+ assert EV(D(a, b)*F(b)) == F(a)
139
+ assert EV(D(i, j)*F(i)) == F(j)
140
+ assert EV(D(i, j)*F(j)) == F(i)
141
+ assert EV(D(p, q)*F(q)) == F(p)
142
+ assert EV(D(p, q)*F(p)) == F(q)
143
+ assert EV(D(p, j)*D(p, i)*F(i)) == F(j)
144
+ assert EV(D(p, j)*D(p, i)*F(j)) == F(i)
145
+ assert EV(D(p, q)*D(p, i))*F(i) == D(q, i)*F(i)
env-llmeval/lib/python3.10/site-packages/sympy/functions/special/tests/test_zeta_functions.py ADDED
@@ -0,0 +1,286 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ from sympy.concrete.summations import Sum
2
+ from sympy.core.function import expand_func
3
+ from sympy.core.numbers import (Float, I, Rational, nan, oo, pi, zoo)
4
+ from sympy.core.singleton import S
5
+ from sympy.core.symbol import Symbol
6
+ from sympy.functions.elementary.complexes import (Abs, polar_lift)
7
+ from sympy.functions.elementary.exponential import (exp, exp_polar, log)
8
+ from sympy.functions.elementary.miscellaneous import sqrt
9
+ from sympy.functions.special.zeta_functions import (dirichlet_eta, lerchphi, polylog, riemann_xi, stieltjes, zeta)
10
+ from sympy.series.order import O
11
+ from sympy.core.function import ArgumentIndexError
12
+ from sympy.functions.combinatorial.numbers import bernoulli, factorial, genocchi, harmonic
13
+ from sympy.testing.pytest import raises
14
+ from sympy.core.random import (test_derivative_numerically as td,
15
+ random_complex_number as randcplx, verify_numerically)
16
+
17
+ x = Symbol('x')
18
+ a = Symbol('a')
19
+ b = Symbol('b', negative=True)
20
+ z = Symbol('z')
21
+ s = Symbol('s')
22
+
23
+
24
+ def test_zeta_eval():
25
+
26
+ assert zeta(nan) is nan
27
+ assert zeta(x, nan) is nan
28
+
29
+ assert zeta(0) == Rational(-1, 2)
30
+ assert zeta(0, x) == S.Half - x
31
+ assert zeta(0, b) == S.Half - b
32
+
33
+ assert zeta(1) is zoo
34
+ assert zeta(1, 2) is zoo
35
+ assert zeta(1, -7) is zoo
36
+ assert zeta(1, x) is zoo
37
+
38
+ assert zeta(2, 1) == pi**2/6
39
+ assert zeta(3, 1) == zeta(3)
40
+
41
+ assert zeta(2) == pi**2/6
42
+ assert zeta(4) == pi**4/90
43
+ assert zeta(6) == pi**6/945
44
+
45
+ assert zeta(4, 3) == pi**4/90 - Rational(17, 16)
46
+ assert zeta(7, 4) == zeta(7) - Rational(282251, 279936)
47
+ assert zeta(S.Half, 2).func == zeta
48
+ assert expand_func(zeta(S.Half, 2)) == zeta(S.Half) - 1
49
+ assert zeta(x, 3).func == zeta
50
+ assert expand_func(zeta(x, 3)) == zeta(x) - 1 - 1/2**x
51
+
52
+ assert zeta(2, 0) is nan
53
+ assert zeta(3, -1) is nan
54
+ assert zeta(4, -2) is nan
55
+
56
+ assert zeta(oo) == 1
57
+
58
+ assert zeta(-1) == Rational(-1, 12)
59
+ assert zeta(-2) == 0
60
+ assert zeta(-3) == Rational(1, 120)
61
+ assert zeta(-4) == 0
62
+ assert zeta(-5) == Rational(-1, 252)
63
+
64
+ assert zeta(-1, 3) == Rational(-37, 12)
65
+ assert zeta(-1, 7) == Rational(-253, 12)
66
+ assert zeta(-1, -4) == Rational(-121, 12)
67
+ assert zeta(-1, -9) == Rational(-541, 12)
68
+
69
+ assert zeta(-4, 3) == -17
70
+ assert zeta(-4, -8) == 8772
71
+
72
+ assert zeta(0, 1) == Rational(-1, 2)
73
+ assert zeta(0, -1) == Rational(3, 2)
74
+
75
+ assert zeta(0, 2) == Rational(-3, 2)
76
+ assert zeta(0, -2) == Rational(5, 2)
77
+
78
+ assert zeta(
79
+ 3).evalf(20).epsilon_eq(Float("1.2020569031595942854", 20), 1e-19)
80
+
81
+
82
+ def test_zeta_series():
83
+ assert zeta(x, a).series(a, z, 2) == \
84
+ zeta(x, z) - x*(a-z)*zeta(x+1, z) + O((a-z)**2, (a, z))
85
+
86
+
87
+ def test_dirichlet_eta_eval():
88
+ assert dirichlet_eta(0) == S.Half
89
+ assert dirichlet_eta(-1) == Rational(1, 4)
90
+ assert dirichlet_eta(1) == log(2)
91
+ assert dirichlet_eta(1, S.Half).simplify() == pi/2
92
+ assert dirichlet_eta(1, 2) == 1 - log(2)
93
+ assert dirichlet_eta(2) == pi**2/12
94
+ assert dirichlet_eta(4) == pi**4*Rational(7, 720)
95
+ assert str(dirichlet_eta(I).evalf(n=10)) == '0.5325931818 + 0.2293848577*I'
96
+ assert str(dirichlet_eta(I, I).evalf(n=10)) == '3.462349253 + 0.220285771*I'
97
+
98
+
99
+ def test_riemann_xi_eval():
100
+ assert riemann_xi(2) == pi/6
101
+ assert riemann_xi(0) == Rational(1, 2)
102
+ assert riemann_xi(1) == Rational(1, 2)
103
+ assert riemann_xi(3).rewrite(zeta) == 3*zeta(3)/(2*pi)
104
+ assert riemann_xi(4) == pi**2/15
105
+
106
+
107
+ def test_rewriting():
108
+ from sympy.functions.elementary.piecewise import Piecewise
109
+ assert isinstance(dirichlet_eta(x).rewrite(zeta), Piecewise)
110
+ assert isinstance(dirichlet_eta(x).rewrite(genocchi), Piecewise)
111
+ assert zeta(x).rewrite(dirichlet_eta) == dirichlet_eta(x)/(1 - 2**(1 - x))
112
+ assert zeta(x).rewrite(dirichlet_eta, a=2) == zeta(x)
113
+ assert verify_numerically(dirichlet_eta(x), dirichlet_eta(x).rewrite(zeta), x)
114
+ assert verify_numerically(dirichlet_eta(x), dirichlet_eta(x).rewrite(genocchi), x)
115
+ assert verify_numerically(zeta(x), zeta(x).rewrite(dirichlet_eta), x)
116
+
117
+ assert zeta(x, a).rewrite(lerchphi) == lerchphi(1, x, a)
118
+ assert polylog(s, z).rewrite(lerchphi) == lerchphi(z, s, 1)*z
119
+
120
+ assert lerchphi(1, x, a).rewrite(zeta) == zeta(x, a)
121
+ assert z*lerchphi(z, s, 1).rewrite(polylog) == polylog(s, z)
122
+
123
+
124
+ def test_derivatives():
125
+ from sympy.core.function import Derivative
126
+ assert zeta(x, a).diff(x) == Derivative(zeta(x, a), x)
127
+ assert zeta(x, a).diff(a) == -x*zeta(x + 1, a)
128
+ assert lerchphi(
129
+ z, s, a).diff(z) == (lerchphi(z, s - 1, a) - a*lerchphi(z, s, a))/z
130
+ assert lerchphi(z, s, a).diff(a) == -s*lerchphi(z, s + 1, a)
131
+ assert polylog(s, z).diff(z) == polylog(s - 1, z)/z
132
+
133
+ b = randcplx()
134
+ c = randcplx()
135
+ assert td(zeta(b, x), x)
136
+ assert td(polylog(b, z), z)
137
+ assert td(lerchphi(c, b, x), x)
138
+ assert td(lerchphi(x, b, c), x)
139
+ raises(ArgumentIndexError, lambda: lerchphi(c, b, x).fdiff(2))
140
+ raises(ArgumentIndexError, lambda: lerchphi(c, b, x).fdiff(4))
141
+ raises(ArgumentIndexError, lambda: polylog(b, z).fdiff(1))
142
+ raises(ArgumentIndexError, lambda: polylog(b, z).fdiff(3))
143
+
144
+
145
+ def myexpand(func, target):
146
+ expanded = expand_func(func)
147
+ if target is not None:
148
+ return expanded == target
149
+ if expanded == func: # it didn't expand
150
+ return False
151
+
152
+ # check to see that the expanded and original evaluate to the same value
153
+ subs = {}
154
+ for a in func.free_symbols:
155
+ subs[a] = randcplx()
156
+ return abs(func.subs(subs).n()
157
+ - expanded.replace(exp_polar, exp).subs(subs).n()) < 1e-10
158
+
159
+
160
+ def test_polylog_expansion():
161
+ assert polylog(s, 0) == 0
162
+ assert polylog(s, 1) == zeta(s)
163
+ assert polylog(s, -1) == -dirichlet_eta(s)
164
+ assert polylog(s, exp_polar(I*pi*Rational(4, 3))) == polylog(s, exp(I*pi*Rational(4, 3)))
165
+ assert polylog(s, exp_polar(I*pi)/3) == polylog(s, exp(I*pi)/3)
166
+
167
+ assert myexpand(polylog(1, z), -log(1 - z))
168
+ assert myexpand(polylog(0, z), z/(1 - z))
169
+ assert myexpand(polylog(-1, z), z/(1 - z)**2)
170
+ assert ((1-z)**3 * expand_func(polylog(-2, z))).simplify() == z*(1 + z)
171
+ assert myexpand(polylog(-5, z), None)
172
+
173
+
174
+ def test_polylog_series():
175
+ assert polylog(1, z).series(z, n=5) == z + z**2/2 + z**3/3 + z**4/4 + O(z**5)
176
+ assert polylog(1, sqrt(z)).series(z, n=3) == z/2 + z**2/4 + sqrt(z)\
177
+ + z**(S(3)/2)/3 + z**(S(5)/2)/5 + O(z**3)
178
+
179
+ # https://github.com/sympy/sympy/issues/9497
180
+ assert polylog(S(3)/2, -z).series(z, 0, 5) == -z + sqrt(2)*z**2/4\
181
+ - sqrt(3)*z**3/9 + z**4/8 + O(z**5)
182
+
183
+
184
+ def test_issue_8404():
185
+ i = Symbol('i', integer=True)
186
+ assert Abs(Sum(1/(3*i + 1)**2, (i, 0, S.Infinity)).doit().n(4)
187
+ - 1.122) < 0.001
188
+
189
+
190
+ def test_polylog_values():
191
+ assert polylog(2, 2) == pi**2/4 - I*pi*log(2)
192
+ assert polylog(2, S.Half) == pi**2/12 - log(2)**2/2
193
+ for z in [S.Half, 2, (sqrt(5)-1)/2, -(sqrt(5)-1)/2, -(sqrt(5)+1)/2, (3-sqrt(5))/2]:
194
+ assert Abs(polylog(2, z).evalf() - polylog(2, z, evaluate=False).evalf()) < 1e-15
195
+ z = Symbol("z")
196
+ for s in [-1, 0]:
197
+ for _ in range(10):
198
+ assert verify_numerically(polylog(s, z), polylog(s, z, evaluate=False),
199
+ z, a=-3, b=-2, c=S.Half, d=2)
200
+ assert verify_numerically(polylog(s, z), polylog(s, z, evaluate=False),
201
+ z, a=2, b=-2, c=5, d=2)
202
+
203
+ from sympy.integrals.integrals import Integral
204
+ assert polylog(0, Integral(1, (x, 0, 1))) == -S.Half
205
+
206
+
207
+ def test_lerchphi_expansion():
208
+ assert myexpand(lerchphi(1, s, a), zeta(s, a))
209
+ assert myexpand(lerchphi(z, s, 1), polylog(s, z)/z)
210
+
211
+ # direct summation
212
+ assert myexpand(lerchphi(z, -1, a), a/(1 - z) + z/(1 - z)**2)
213
+ assert myexpand(lerchphi(z, -3, a), None)
214
+ # polylog reduction
215
+ assert myexpand(lerchphi(z, s, S.Half),
216
+ 2**(s - 1)*(polylog(s, sqrt(z))/sqrt(z)
217
+ - polylog(s, polar_lift(-1)*sqrt(z))/sqrt(z)))
218
+ assert myexpand(lerchphi(z, s, 2), -1/z + polylog(s, z)/z**2)
219
+ assert myexpand(lerchphi(z, s, Rational(3, 2)), None)
220
+ assert myexpand(lerchphi(z, s, Rational(7, 3)), None)
221
+ assert myexpand(lerchphi(z, s, Rational(-1, 3)), None)
222
+ assert myexpand(lerchphi(z, s, Rational(-5, 2)), None)
223
+
224
+ # hurwitz zeta reduction
225
+ assert myexpand(lerchphi(-1, s, a),
226
+ 2**(-s)*zeta(s, a/2) - 2**(-s)*zeta(s, (a + 1)/2))
227
+ assert myexpand(lerchphi(I, s, a), None)
228
+ assert myexpand(lerchphi(-I, s, a), None)
229
+ assert myexpand(lerchphi(exp(I*pi*Rational(2, 5)), s, a), None)
230
+
231
+
232
+ def test_stieltjes():
233
+ assert isinstance(stieltjes(x), stieltjes)
234
+ assert isinstance(stieltjes(x, a), stieltjes)
235
+
236
+ # Zero'th constant EulerGamma
237
+ assert stieltjes(0) == S.EulerGamma
238
+ assert stieltjes(0, 1) == S.EulerGamma
239
+
240
+ # Not defined
241
+ assert stieltjes(nan) is nan
242
+ assert stieltjes(0, nan) is nan
243
+ assert stieltjes(-1) is S.ComplexInfinity
244
+ assert stieltjes(1.5) is S.ComplexInfinity
245
+ assert stieltjes(z, 0) is S.ComplexInfinity
246
+ assert stieltjes(z, -1) is S.ComplexInfinity
247
+
248
+
249
+ def test_stieltjes_evalf():
250
+ assert abs(stieltjes(0).evalf() - 0.577215664) < 1E-9
251
+ assert abs(stieltjes(0, 0.5).evalf() - 1.963510026) < 1E-9
252
+ assert abs(stieltjes(1, 2).evalf() + 0.072815845) < 1E-9
253
+
254
+
255
+ def test_issue_10475():
256
+ a = Symbol('a', extended_real=True)
257
+ b = Symbol('b', extended_positive=True)
258
+ s = Symbol('s', zero=False)
259
+
260
+ assert zeta(2 + I).is_finite
261
+ assert zeta(1).is_finite is False
262
+ assert zeta(x).is_finite is None
263
+ assert zeta(x + I).is_finite is None
264
+ assert zeta(a).is_finite is None
265
+ assert zeta(b).is_finite is None
266
+ assert zeta(-b).is_finite is True
267
+ assert zeta(b**2 - 2*b + 1).is_finite is None
268
+ assert zeta(a + I).is_finite is True
269
+ assert zeta(b + 1).is_finite is True
270
+ assert zeta(s + 1).is_finite is True
271
+
272
+
273
+ def test_issue_14177():
274
+ n = Symbol('n', nonnegative=True, integer=True)
275
+
276
+ assert zeta(-n).rewrite(bernoulli) == bernoulli(n+1) / (-n-1)
277
+ assert zeta(-n, a).rewrite(bernoulli) == bernoulli(n+1, a) / (-n-1)
278
+ z2n = -(2*I*pi)**(2*n)*bernoulli(2*n) / (2*factorial(2*n))
279
+ assert zeta(2*n).rewrite(bernoulli) == z2n
280
+ assert expand_func(zeta(s, n+1)) == zeta(s) - harmonic(n, s)
281
+ assert expand_func(zeta(-b, -n)) is nan
282
+ assert expand_func(zeta(-b, n)) == zeta(-b, n)
283
+
284
+ n = Symbol('n')
285
+
286
+ assert zeta(2*n) == zeta(2*n) # As sign of z (= 2*n) is not determined
env-llmeval/lib/python3.10/site-packages/sympy/logic/__init__.py ADDED
@@ -0,0 +1,12 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ from .boolalg import (to_cnf, to_dnf, to_nnf, And, Or, Not, Xor, Nand, Nor, Implies,
2
+ Equivalent, ITE, POSform, SOPform, simplify_logic, bool_map, true, false,
3
+ gateinputcount)
4
+ from .inference import satisfiable
5
+
6
+ __all__ = [
7
+ 'to_cnf', 'to_dnf', 'to_nnf', 'And', 'Or', 'Not', 'Xor', 'Nand', 'Nor',
8
+ 'Implies', 'Equivalent', 'ITE', 'POSform', 'SOPform', 'simplify_logic',
9
+ 'bool_map', 'true', 'false', 'gateinputcount',
10
+
11
+ 'satisfiable',
12
+ ]
env-llmeval/lib/python3.10/site-packages/sympy/logic/__pycache__/__init__.cpython-310.pyc ADDED
Binary file (687 Bytes). View file
 
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1
+ """Implementation of DPLL algorithm
2
+
3
+ Further improvements: eliminate calls to pl_true, implement branching rules,
4
+ efficient unit propagation.
5
+
6
+ References:
7
+ - https://en.wikipedia.org/wiki/DPLL_algorithm
8
+ - https://www.researchgate.net/publication/242384772_Implementations_of_the_DPLL_Algorithm
9
+ """
10
+
11
+ from sympy.core.sorting import default_sort_key
12
+ from sympy.logic.boolalg import Or, Not, conjuncts, disjuncts, to_cnf, \
13
+ to_int_repr, _find_predicates
14
+ from sympy.assumptions.cnf import CNF
15
+ from sympy.logic.inference import pl_true, literal_symbol
16
+
17
+
18
+ def dpll_satisfiable(expr):
19
+ """
20
+ Check satisfiability of a propositional sentence.
21
+ It returns a model rather than True when it succeeds
22
+
23
+ >>> from sympy.abc import A, B
24
+ >>> from sympy.logic.algorithms.dpll import dpll_satisfiable
25
+ >>> dpll_satisfiable(A & ~B)
26
+ {A: True, B: False}
27
+ >>> dpll_satisfiable(A & ~A)
28
+ False
29
+
30
+ """
31
+ if not isinstance(expr, CNF):
32
+ clauses = conjuncts(to_cnf(expr))
33
+ else:
34
+ clauses = expr.clauses
35
+ if False in clauses:
36
+ return False
37
+ symbols = sorted(_find_predicates(expr), key=default_sort_key)
38
+ symbols_int_repr = set(range(1, len(symbols) + 1))
39
+ clauses_int_repr = to_int_repr(clauses, symbols)
40
+ result = dpll_int_repr(clauses_int_repr, symbols_int_repr, {})
41
+ if not result:
42
+ return result
43
+ output = {}
44
+ for key in result:
45
+ output.update({symbols[key - 1]: result[key]})
46
+ return output
47
+
48
+
49
+ def dpll(clauses, symbols, model):
50
+ """
51
+ Compute satisfiability in a partial model.
52
+ Clauses is an array of conjuncts.
53
+
54
+ >>> from sympy.abc import A, B, D
55
+ >>> from sympy.logic.algorithms.dpll import dpll
56
+ >>> dpll([A, B, D], [A, B], {D: False})
57
+ False
58
+
59
+ """
60
+ # compute DP kernel
61
+ P, value = find_unit_clause(clauses, model)
62
+ while P:
63
+ model.update({P: value})
64
+ symbols.remove(P)
65
+ if not value:
66
+ P = ~P
67
+ clauses = unit_propagate(clauses, P)
68
+ P, value = find_unit_clause(clauses, model)
69
+ P, value = find_pure_symbol(symbols, clauses)
70
+ while P:
71
+ model.update({P: value})
72
+ symbols.remove(P)
73
+ if not value:
74
+ P = ~P
75
+ clauses = unit_propagate(clauses, P)
76
+ P, value = find_pure_symbol(symbols, clauses)
77
+ # end DP kernel
78
+ unknown_clauses = []
79
+ for c in clauses:
80
+ val = pl_true(c, model)
81
+ if val is False:
82
+ return False
83
+ if val is not True:
84
+ unknown_clauses.append(c)
85
+ if not unknown_clauses:
86
+ return model
87
+ if not clauses:
88
+ return model
89
+ P = symbols.pop()
90
+ model_copy = model.copy()
91
+ model.update({P: True})
92
+ model_copy.update({P: False})
93
+ symbols_copy = symbols[:]
94
+ return (dpll(unit_propagate(unknown_clauses, P), symbols, model) or
95
+ dpll(unit_propagate(unknown_clauses, Not(P)), symbols_copy, model_copy))
96
+
97
+
98
+ def dpll_int_repr(clauses, symbols, model):
99
+ """
100
+ Compute satisfiability in a partial model.
101
+ Arguments are expected to be in integer representation
102
+
103
+ >>> from sympy.logic.algorithms.dpll import dpll_int_repr
104
+ >>> dpll_int_repr([{1}, {2}, {3}], {1, 2}, {3: False})
105
+ False
106
+
107
+ """
108
+ # compute DP kernel
109
+ P, value = find_unit_clause_int_repr(clauses, model)
110
+ while P:
111
+ model.update({P: value})
112
+ symbols.remove(P)
113
+ if not value:
114
+ P = -P
115
+ clauses = unit_propagate_int_repr(clauses, P)
116
+ P, value = find_unit_clause_int_repr(clauses, model)
117
+ P, value = find_pure_symbol_int_repr(symbols, clauses)
118
+ while P:
119
+ model.update({P: value})
120
+ symbols.remove(P)
121
+ if not value:
122
+ P = -P
123
+ clauses = unit_propagate_int_repr(clauses, P)
124
+ P, value = find_pure_symbol_int_repr(symbols, clauses)
125
+ # end DP kernel
126
+ unknown_clauses = []
127
+ for c in clauses:
128
+ val = pl_true_int_repr(c, model)
129
+ if val is False:
130
+ return False
131
+ if val is not True:
132
+ unknown_clauses.append(c)
133
+ if not unknown_clauses:
134
+ return model
135
+ P = symbols.pop()
136
+ model_copy = model.copy()
137
+ model.update({P: True})
138
+ model_copy.update({P: False})
139
+ symbols_copy = symbols.copy()
140
+ return (dpll_int_repr(unit_propagate_int_repr(unknown_clauses, P), symbols, model) or
141
+ dpll_int_repr(unit_propagate_int_repr(unknown_clauses, -P), symbols_copy, model_copy))
142
+
143
+ ### helper methods for DPLL
144
+
145
+
146
+ def pl_true_int_repr(clause, model={}):
147
+ """
148
+ Lightweight version of pl_true.
149
+ Argument clause represents the set of args of an Or clause. This is used
150
+ inside dpll_int_repr, it is not meant to be used directly.
151
+
152
+ >>> from sympy.logic.algorithms.dpll import pl_true_int_repr
153
+ >>> pl_true_int_repr({1, 2}, {1: False})
154
+ >>> pl_true_int_repr({1, 2}, {1: False, 2: False})
155
+ False
156
+
157
+ """
158
+ result = False
159
+ for lit in clause:
160
+ if lit < 0:
161
+ p = model.get(-lit)
162
+ if p is not None:
163
+ p = not p
164
+ else:
165
+ p = model.get(lit)
166
+ if p is True:
167
+ return True
168
+ elif p is None:
169
+ result = None
170
+ return result
171
+
172
+
173
+ def unit_propagate(clauses, symbol):
174
+ """
175
+ Returns an equivalent set of clauses
176
+ If a set of clauses contains the unit clause l, the other clauses are
177
+ simplified by the application of the two following rules:
178
+
179
+ 1. every clause containing l is removed
180
+ 2. in every clause that contains ~l this literal is deleted
181
+
182
+ Arguments are expected to be in CNF.
183
+
184
+ >>> from sympy.abc import A, B, D
185
+ >>> from sympy.logic.algorithms.dpll import unit_propagate
186
+ >>> unit_propagate([A | B, D | ~B, B], B)
187
+ [D, B]
188
+
189
+ """
190
+ output = []
191
+ for c in clauses:
192
+ if c.func != Or:
193
+ output.append(c)
194
+ continue
195
+ for arg in c.args:
196
+ if arg == ~symbol:
197
+ output.append(Or(*[x for x in c.args if x != ~symbol]))
198
+ break
199
+ if arg == symbol:
200
+ break
201
+ else:
202
+ output.append(c)
203
+ return output
204
+
205
+
206
+ def unit_propagate_int_repr(clauses, s):
207
+ """
208
+ Same as unit_propagate, but arguments are expected to be in integer
209
+ representation
210
+
211
+ >>> from sympy.logic.algorithms.dpll import unit_propagate_int_repr
212
+ >>> unit_propagate_int_repr([{1, 2}, {3, -2}, {2}], 2)
213
+ [{3}]
214
+
215
+ """
216
+ negated = {-s}
217
+ return [clause - negated for clause in clauses if s not in clause]
218
+
219
+
220
+ def find_pure_symbol(symbols, unknown_clauses):
221
+ """
222
+ Find a symbol and its value if it appears only as a positive literal
223
+ (or only as a negative) in clauses.
224
+
225
+ >>> from sympy.abc import A, B, D
226
+ >>> from sympy.logic.algorithms.dpll import find_pure_symbol
227
+ >>> find_pure_symbol([A, B, D], [A|~B,~B|~D,D|A])
228
+ (A, True)
229
+
230
+ """
231
+ for sym in symbols:
232
+ found_pos, found_neg = False, False
233
+ for c in unknown_clauses:
234
+ if not found_pos and sym in disjuncts(c):
235
+ found_pos = True
236
+ if not found_neg and Not(sym) in disjuncts(c):
237
+ found_neg = True
238
+ if found_pos != found_neg:
239
+ return sym, found_pos
240
+ return None, None
241
+
242
+
243
+ def find_pure_symbol_int_repr(symbols, unknown_clauses):
244
+ """
245
+ Same as find_pure_symbol, but arguments are expected
246
+ to be in integer representation
247
+
248
+ >>> from sympy.logic.algorithms.dpll import find_pure_symbol_int_repr
249
+ >>> find_pure_symbol_int_repr({1,2,3},
250
+ ... [{1, -2}, {-2, -3}, {3, 1}])
251
+ (1, True)
252
+
253
+ """
254
+ all_symbols = set().union(*unknown_clauses)
255
+ found_pos = all_symbols.intersection(symbols)
256
+ found_neg = all_symbols.intersection([-s for s in symbols])
257
+ for p in found_pos:
258
+ if -p not in found_neg:
259
+ return p, True
260
+ for p in found_neg:
261
+ if -p not in found_pos:
262
+ return -p, False
263
+ return None, None
264
+
265
+
266
+ def find_unit_clause(clauses, model):
267
+ """
268
+ A unit clause has only 1 variable that is not bound in the model.
269
+
270
+ >>> from sympy.abc import A, B, D
271
+ >>> from sympy.logic.algorithms.dpll import find_unit_clause
272
+ >>> find_unit_clause([A | B | D, B | ~D, A | ~B], {A:True})
273
+ (B, False)
274
+
275
+ """
276
+ for clause in clauses:
277
+ num_not_in_model = 0
278
+ for literal in disjuncts(clause):
279
+ sym = literal_symbol(literal)
280
+ if sym not in model:
281
+ num_not_in_model += 1
282
+ P, value = sym, not isinstance(literal, Not)
283
+ if num_not_in_model == 1:
284
+ return P, value
285
+ return None, None
286
+
287
+
288
+ def find_unit_clause_int_repr(clauses, model):
289
+ """
290
+ Same as find_unit_clause, but arguments are expected to be in
291
+ integer representation.
292
+
293
+ >>> from sympy.logic.algorithms.dpll import find_unit_clause_int_repr
294
+ >>> find_unit_clause_int_repr([{1, 2, 3},
295
+ ... {2, -3}, {1, -2}], {1: True})
296
+ (2, False)
297
+
298
+ """
299
+ bound = set(model) | {-sym for sym in model}
300
+ for clause in clauses:
301
+ unbound = clause - bound
302
+ if len(unbound) == 1:
303
+ p = unbound.pop()
304
+ if p < 0:
305
+ return -p, False
306
+ else:
307
+ return p, True
308
+ return None, None