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  1. .gitattributes +1 -0
  2. llmeval-env/lib/python3.10/site-packages/nvidia/cusparse/lib/libcusparse.so.12 +3 -0
  3. llmeval-env/lib/python3.10/site-packages/sympy/polys/agca/__init__.py +5 -0
  4. llmeval-env/lib/python3.10/site-packages/sympy/polys/agca/__pycache__/__init__.cpython-310.pyc +0 -0
  5. llmeval-env/lib/python3.10/site-packages/sympy/polys/agca/__pycache__/extensions.cpython-310.pyc +0 -0
  6. llmeval-env/lib/python3.10/site-packages/sympy/polys/agca/__pycache__/homomorphisms.cpython-310.pyc +0 -0
  7. llmeval-env/lib/python3.10/site-packages/sympy/polys/agca/__pycache__/ideals.cpython-310.pyc +0 -0
  8. llmeval-env/lib/python3.10/site-packages/sympy/polys/agca/__pycache__/modules.cpython-310.pyc +0 -0
  9. llmeval-env/lib/python3.10/site-packages/sympy/polys/agca/extensions.py +346 -0
  10. llmeval-env/lib/python3.10/site-packages/sympy/polys/agca/homomorphisms.py +691 -0
  11. llmeval-env/lib/python3.10/site-packages/sympy/polys/agca/ideals.py +394 -0
  12. llmeval-env/lib/python3.10/site-packages/sympy/polys/agca/modules.py +1484 -0
  13. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__init__.py +0 -0
  14. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/__init__.cpython-310.pyc +0 -0
  15. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_appellseqs.cpython-310.pyc +0 -0
  16. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_constructor.cpython-310.pyc +0 -0
  17. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_densearith.cpython-310.pyc +0 -0
  18. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_densebasic.cpython-310.pyc +0 -0
  19. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_densetools.cpython-310.pyc +0 -0
  20. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_dispersion.cpython-310.pyc +0 -0
  21. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_distributedmodules.cpython-310.pyc +0 -0
  22. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_euclidtools.cpython-310.pyc +0 -0
  23. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_factortools.cpython-310.pyc +0 -0
  24. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_fields.cpython-310.pyc +0 -0
  25. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_galoistools.cpython-310.pyc +0 -0
  26. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_groebnertools.cpython-310.pyc +0 -0
  27. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_heuristicgcd.cpython-310.pyc +0 -0
  28. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_injections.cpython-310.pyc +0 -0
  29. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_modulargcd.cpython-310.pyc +0 -0
  30. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_monomials.cpython-310.pyc +0 -0
  31. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_multivariate_resultants.cpython-310.pyc +0 -0
  32. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_orderings.cpython-310.pyc +0 -0
  33. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_orthopolys.cpython-310.pyc +0 -0
  34. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_partfrac.cpython-310.pyc +0 -0
  35. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_polyclasses.cpython-310.pyc +0 -0
  36. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_polyfuncs.cpython-310.pyc +0 -0
  37. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_polymatrix.cpython-310.pyc +0 -0
  38. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_polyoptions.cpython-310.pyc +0 -0
  39. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_polyroots.cpython-310.pyc +0 -0
  40. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_polytools.cpython-310.pyc +0 -0
  41. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_polyutils.cpython-310.pyc +0 -0
  42. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_pythonrational.cpython-310.pyc +0 -0
  43. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_rationaltools.cpython-310.pyc +0 -0
  44. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_ring_series.cpython-310.pyc +0 -0
  45. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_rings.cpython-310.pyc +0 -0
  46. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_rootisolation.cpython-310.pyc +0 -0
  47. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_rootoftools.cpython-310.pyc +0 -0
  48. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_solvers.cpython-310.pyc +0 -0
  49. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_specialpolys.cpython-310.pyc +0 -0
  50. llmeval-env/lib/python3.10/site-packages/sympy/polys/tests/__pycache__/test_sqfreetools.cpython-310.pyc +0 -0
.gitattributes CHANGED
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188
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+ llmeval-env/lib/python3.10/site-packages/nvidia/cusparse/lib/libcusparse.so.12 filter=lfs diff=lfs merge=lfs -text
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llmeval-env/lib/python3.10/site-packages/sympy/polys/agca/__init__.py ADDED
@@ -0,0 +1,5 @@
 
 
 
 
 
 
1
+ """Module for algebraic geometry and commutative algebra."""
2
+
3
+ from .homomorphisms import homomorphism
4
+
5
+ __all__ = ['homomorphism']
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1
+ """Finite extensions of ring domains."""
2
+
3
+ from sympy.polys.domains.domain import Domain
4
+ from sympy.polys.domains.domainelement import DomainElement
5
+ from sympy.polys.polyerrors import (CoercionFailed, NotInvertible,
6
+ GeneratorsError)
7
+ from sympy.polys.polytools import Poly
8
+ from sympy.printing.defaults import DefaultPrinting
9
+
10
+
11
+ class ExtensionElement(DomainElement, DefaultPrinting):
12
+ """
13
+ Element of a finite extension.
14
+
15
+ A class of univariate polynomials modulo the ``modulus``
16
+ of the extension ``ext``. It is represented by the
17
+ unique polynomial ``rep`` of lowest degree. Both
18
+ ``rep`` and the representation ``mod`` of ``modulus``
19
+ are of class DMP.
20
+
21
+ """
22
+ __slots__ = ('rep', 'ext')
23
+
24
+ def __init__(self, rep, ext):
25
+ self.rep = rep
26
+ self.ext = ext
27
+
28
+ def parent(f):
29
+ return f.ext
30
+
31
+ def __bool__(f):
32
+ return bool(f.rep)
33
+
34
+ def __pos__(f):
35
+ return f
36
+
37
+ def __neg__(f):
38
+ return ExtElem(-f.rep, f.ext)
39
+
40
+ def _get_rep(f, g):
41
+ if isinstance(g, ExtElem):
42
+ if g.ext == f.ext:
43
+ return g.rep
44
+ else:
45
+ return None
46
+ else:
47
+ try:
48
+ g = f.ext.convert(g)
49
+ return g.rep
50
+ except CoercionFailed:
51
+ return None
52
+
53
+ def __add__(f, g):
54
+ rep = f._get_rep(g)
55
+ if rep is not None:
56
+ return ExtElem(f.rep + rep, f.ext)
57
+ else:
58
+ return NotImplemented
59
+
60
+ __radd__ = __add__
61
+
62
+ def __sub__(f, g):
63
+ rep = f._get_rep(g)
64
+ if rep is not None:
65
+ return ExtElem(f.rep - rep, f.ext)
66
+ else:
67
+ return NotImplemented
68
+
69
+ def __rsub__(f, g):
70
+ rep = f._get_rep(g)
71
+ if rep is not None:
72
+ return ExtElem(rep - f.rep, f.ext)
73
+ else:
74
+ return NotImplemented
75
+
76
+ def __mul__(f, g):
77
+ rep = f._get_rep(g)
78
+ if rep is not None:
79
+ return ExtElem((f.rep * rep) % f.ext.mod, f.ext)
80
+ else:
81
+ return NotImplemented
82
+
83
+ __rmul__ = __mul__
84
+
85
+ def _divcheck(f):
86
+ """Raise if division is not implemented for this divisor"""
87
+ if not f:
88
+ raise NotInvertible('Zero divisor')
89
+ elif f.ext.is_Field:
90
+ return True
91
+ elif f.rep.is_ground and f.ext.domain.is_unit(f.rep.rep[0]):
92
+ return True
93
+ else:
94
+ # Some cases like (2*x + 2)/2 over ZZ will fail here. It is
95
+ # unclear how to implement division in general if the ground
96
+ # domain is not a field so for now it was decided to restrict the
97
+ # implementation to division by invertible constants.
98
+ msg = (f"Can not invert {f} in {f.ext}. "
99
+ "Only division by invertible constants is implemented.")
100
+ raise NotImplementedError(msg)
101
+
102
+ def inverse(f):
103
+ """Multiplicative inverse.
104
+
105
+ Raises
106
+ ======
107
+
108
+ NotInvertible
109
+ If the element is a zero divisor.
110
+
111
+ """
112
+ f._divcheck()
113
+
114
+ if f.ext.is_Field:
115
+ invrep = f.rep.invert(f.ext.mod)
116
+ else:
117
+ R = f.ext.ring
118
+ invrep = R.exquo(R.one, f.rep)
119
+
120
+ return ExtElem(invrep, f.ext)
121
+
122
+ def __truediv__(f, g):
123
+ rep = f._get_rep(g)
124
+ if rep is None:
125
+ return NotImplemented
126
+ g = ExtElem(rep, f.ext)
127
+
128
+ try:
129
+ ginv = g.inverse()
130
+ except NotInvertible:
131
+ raise ZeroDivisionError(f"{f} / {g}")
132
+
133
+ return f * ginv
134
+
135
+ __floordiv__ = __truediv__
136
+
137
+ def __rtruediv__(f, g):
138
+ try:
139
+ g = f.ext.convert(g)
140
+ except CoercionFailed:
141
+ return NotImplemented
142
+ return g / f
143
+
144
+ __rfloordiv__ = __rtruediv__
145
+
146
+ def __mod__(f, g):
147
+ rep = f._get_rep(g)
148
+ if rep is None:
149
+ return NotImplemented
150
+ g = ExtElem(rep, f.ext)
151
+
152
+ try:
153
+ g._divcheck()
154
+ except NotInvertible:
155
+ raise ZeroDivisionError(f"{f} % {g}")
156
+
157
+ # Division where defined is always exact so there is no remainder
158
+ return f.ext.zero
159
+
160
+ def __rmod__(f, g):
161
+ try:
162
+ g = f.ext.convert(g)
163
+ except CoercionFailed:
164
+ return NotImplemented
165
+ return g % f
166
+
167
+ def __pow__(f, n):
168
+ if not isinstance(n, int):
169
+ raise TypeError("exponent of type 'int' expected")
170
+ if n < 0:
171
+ try:
172
+ f, n = f.inverse(), -n
173
+ except NotImplementedError:
174
+ raise ValueError("negative powers are not defined")
175
+
176
+ b = f.rep
177
+ m = f.ext.mod
178
+ r = f.ext.one.rep
179
+ while n > 0:
180
+ if n % 2:
181
+ r = (r*b) % m
182
+ b = (b*b) % m
183
+ n //= 2
184
+
185
+ return ExtElem(r, f.ext)
186
+
187
+ def __eq__(f, g):
188
+ if isinstance(g, ExtElem):
189
+ return f.rep == g.rep and f.ext == g.ext
190
+ else:
191
+ return NotImplemented
192
+
193
+ def __ne__(f, g):
194
+ return not f == g
195
+
196
+ def __hash__(f):
197
+ return hash((f.rep, f.ext))
198
+
199
+ def __str__(f):
200
+ from sympy.printing.str import sstr
201
+ return sstr(f.rep)
202
+
203
+ __repr__ = __str__
204
+
205
+ @property
206
+ def is_ground(f):
207
+ return f.rep.is_ground
208
+
209
+ def to_ground(f):
210
+ [c] = f.rep.to_list()
211
+ return c
212
+
213
+ ExtElem = ExtensionElement
214
+
215
+
216
+ class MonogenicFiniteExtension(Domain):
217
+ r"""
218
+ Finite extension generated by an integral element.
219
+
220
+ The generator is defined by a monic univariate
221
+ polynomial derived from the argument ``mod``.
222
+
223
+ A shorter alias is ``FiniteExtension``.
224
+
225
+ Examples
226
+ ========
227
+
228
+ Quadratic integer ring $\mathbb{Z}[\sqrt2]$:
229
+
230
+ >>> from sympy import Symbol, Poly
231
+ >>> from sympy.polys.agca.extensions import FiniteExtension
232
+ >>> x = Symbol('x')
233
+ >>> R = FiniteExtension(Poly(x**2 - 2)); R
234
+ ZZ[x]/(x**2 - 2)
235
+ >>> R.rank
236
+ 2
237
+ >>> R(1 + x)*(3 - 2*x)
238
+ x - 1
239
+
240
+ Finite field $GF(5^3)$ defined by the primitive
241
+ polynomial $x^3 + x^2 + 2$ (over $\mathbb{Z}_5$).
242
+
243
+ >>> F = FiniteExtension(Poly(x**3 + x**2 + 2, modulus=5)); F
244
+ GF(5)[x]/(x**3 + x**2 + 2)
245
+ >>> F.basis
246
+ (1, x, x**2)
247
+ >>> F(x + 3)/(x**2 + 2)
248
+ -2*x**2 + x + 2
249
+
250
+ Function field of an elliptic curve:
251
+
252
+ >>> t = Symbol('t')
253
+ >>> FiniteExtension(Poly(t**2 - x**3 - x + 1, t, field=True))
254
+ ZZ(x)[t]/(t**2 - x**3 - x + 1)
255
+
256
+ """
257
+ is_FiniteExtension = True
258
+
259
+ dtype = ExtensionElement
260
+
261
+ def __init__(self, mod):
262
+ if not (isinstance(mod, Poly) and mod.is_univariate):
263
+ raise TypeError("modulus must be a univariate Poly")
264
+
265
+ # Using auto=True (default) potentially changes the ground domain to a
266
+ # field whereas auto=False raises if division is not exact. We'll let
267
+ # the caller decide whether or not they want to put the ground domain
268
+ # over a field. In most uses mod is already monic.
269
+ mod = mod.monic(auto=False)
270
+
271
+ self.rank = mod.degree()
272
+ self.modulus = mod
273
+ self.mod = mod.rep # DMP representation
274
+
275
+ self.domain = dom = mod.domain
276
+ self.ring = mod.rep.ring or dom.old_poly_ring(*mod.gens)
277
+
278
+ self.zero = self.convert(self.ring.zero)
279
+ self.one = self.convert(self.ring.one)
280
+
281
+ gen = self.ring.gens[0]
282
+ self.symbol = self.ring.symbols[0]
283
+ self.generator = self.convert(gen)
284
+ self.basis = tuple(self.convert(gen**i) for i in range(self.rank))
285
+
286
+ # XXX: It might be necessary to check mod.is_irreducible here
287
+ self.is_Field = self.domain.is_Field
288
+
289
+ def new(self, arg):
290
+ rep = self.ring.convert(arg)
291
+ return ExtElem(rep % self.mod, self)
292
+
293
+ def __eq__(self, other):
294
+ if not isinstance(other, FiniteExtension):
295
+ return False
296
+ return self.modulus == other.modulus
297
+
298
+ def __hash__(self):
299
+ return hash((self.__class__.__name__, self.modulus))
300
+
301
+ def __str__(self):
302
+ return "%s/(%s)" % (self.ring, self.modulus.as_expr())
303
+
304
+ __repr__ = __str__
305
+
306
+ def convert(self, f, base=None):
307
+ rep = self.ring.convert(f, base)
308
+ return ExtElem(rep % self.mod, self)
309
+
310
+ def convert_from(self, f, base):
311
+ rep = self.ring.convert(f, base)
312
+ return ExtElem(rep % self.mod, self)
313
+
314
+ def to_sympy(self, f):
315
+ return self.ring.to_sympy(f.rep)
316
+
317
+ def from_sympy(self, f):
318
+ return self.convert(f)
319
+
320
+ def set_domain(self, K):
321
+ mod = self.modulus.set_domain(K)
322
+ return self.__class__(mod)
323
+
324
+ def drop(self, *symbols):
325
+ if self.symbol in symbols:
326
+ raise GeneratorsError('Can not drop generator from FiniteExtension')
327
+ K = self.domain.drop(*symbols)
328
+ return self.set_domain(K)
329
+
330
+ def quo(self, f, g):
331
+ return self.exquo(f, g)
332
+
333
+ def exquo(self, f, g):
334
+ rep = self.ring.exquo(f.rep, g.rep)
335
+ return ExtElem(rep % self.mod, self)
336
+
337
+ def is_negative(self, a):
338
+ return False
339
+
340
+ def is_unit(self, a):
341
+ if self.is_Field:
342
+ return bool(a)
343
+ elif a.is_ground:
344
+ return self.domain.is_unit(a.to_ground())
345
+
346
+ FiniteExtension = MonogenicFiniteExtension
llmeval-env/lib/python3.10/site-packages/sympy/polys/agca/homomorphisms.py ADDED
@@ -0,0 +1,691 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ """
2
+ Computations with homomorphisms of modules and rings.
3
+
4
+ This module implements classes for representing homomorphisms of rings and
5
+ their modules. Instead of instantiating the classes directly, you should use
6
+ the function ``homomorphism(from, to, matrix)`` to create homomorphism objects.
7
+ """
8
+
9
+
10
+ from sympy.polys.agca.modules import (Module, FreeModule, QuotientModule,
11
+ SubModule, SubQuotientModule)
12
+ from sympy.polys.polyerrors import CoercionFailed
13
+
14
+ # The main computational task for module homomorphisms is kernels.
15
+ # For this reason, the concrete classes are organised by domain module type.
16
+
17
+
18
+ class ModuleHomomorphism:
19
+ """
20
+ Abstract base class for module homomoprhisms. Do not instantiate.
21
+
22
+ Instead, use the ``homomorphism`` function:
23
+
24
+ >>> from sympy import QQ
25
+ >>> from sympy.abc import x
26
+ >>> from sympy.polys.agca import homomorphism
27
+
28
+ >>> F = QQ.old_poly_ring(x).free_module(2)
29
+ >>> homomorphism(F, F, [[1, 0], [0, 1]])
30
+ Matrix([
31
+ [1, 0], : QQ[x]**2 -> QQ[x]**2
32
+ [0, 1]])
33
+
34
+ Attributes:
35
+
36
+ - ring - the ring over which we are considering modules
37
+ - domain - the domain module
38
+ - codomain - the codomain module
39
+ - _ker - cached kernel
40
+ - _img - cached image
41
+
42
+ Non-implemented methods:
43
+
44
+ - _kernel
45
+ - _image
46
+ - _restrict_domain
47
+ - _restrict_codomain
48
+ - _quotient_domain
49
+ - _quotient_codomain
50
+ - _apply
51
+ - _mul_scalar
52
+ - _compose
53
+ - _add
54
+ """
55
+
56
+ def __init__(self, domain, codomain):
57
+ if not isinstance(domain, Module):
58
+ raise TypeError('Source must be a module, got %s' % domain)
59
+ if not isinstance(codomain, Module):
60
+ raise TypeError('Target must be a module, got %s' % codomain)
61
+ if domain.ring != codomain.ring:
62
+ raise ValueError('Source and codomain must be over same ring, '
63
+ 'got %s != %s' % (domain, codomain))
64
+ self.domain = domain
65
+ self.codomain = codomain
66
+ self.ring = domain.ring
67
+ self._ker = None
68
+ self._img = None
69
+
70
+ def kernel(self):
71
+ r"""
72
+ Compute the kernel of ``self``.
73
+
74
+ That is, if ``self`` is the homomorphism `\phi: M \to N`, then compute
75
+ `ker(\phi) = \{x \in M | \phi(x) = 0\}`. This is a submodule of `M`.
76
+
77
+ Examples
78
+ ========
79
+
80
+ >>> from sympy import QQ
81
+ >>> from sympy.abc import x
82
+ >>> from sympy.polys.agca import homomorphism
83
+
84
+ >>> F = QQ.old_poly_ring(x).free_module(2)
85
+ >>> homomorphism(F, F, [[1, 0], [x, 0]]).kernel()
86
+ <[x, -1]>
87
+ """
88
+ if self._ker is None:
89
+ self._ker = self._kernel()
90
+ return self._ker
91
+
92
+ def image(self):
93
+ r"""
94
+ Compute the image of ``self``.
95
+
96
+ That is, if ``self`` is the homomorphism `\phi: M \to N`, then compute
97
+ `im(\phi) = \{\phi(x) | x \in M \}`. This is a submodule of `N`.
98
+
99
+ Examples
100
+ ========
101
+
102
+ >>> from sympy import QQ
103
+ >>> from sympy.abc import x
104
+ >>> from sympy.polys.agca import homomorphism
105
+
106
+ >>> F = QQ.old_poly_ring(x).free_module(2)
107
+ >>> homomorphism(F, F, [[1, 0], [x, 0]]).image() == F.submodule([1, 0])
108
+ True
109
+ """
110
+ if self._img is None:
111
+ self._img = self._image()
112
+ return self._img
113
+
114
+ def _kernel(self):
115
+ """Compute the kernel of ``self``."""
116
+ raise NotImplementedError
117
+
118
+ def _image(self):
119
+ """Compute the image of ``self``."""
120
+ raise NotImplementedError
121
+
122
+ def _restrict_domain(self, sm):
123
+ """Implementation of domain restriction."""
124
+ raise NotImplementedError
125
+
126
+ def _restrict_codomain(self, sm):
127
+ """Implementation of codomain restriction."""
128
+ raise NotImplementedError
129
+
130
+ def _quotient_domain(self, sm):
131
+ """Implementation of domain quotient."""
132
+ raise NotImplementedError
133
+
134
+ def _quotient_codomain(self, sm):
135
+ """Implementation of codomain quotient."""
136
+ raise NotImplementedError
137
+
138
+ def restrict_domain(self, sm):
139
+ """
140
+ Return ``self``, with the domain restricted to ``sm``.
141
+
142
+ Here ``sm`` has to be a submodule of ``self.domain``.
143
+
144
+ Examples
145
+ ========
146
+
147
+ >>> from sympy import QQ
148
+ >>> from sympy.abc import x
149
+ >>> from sympy.polys.agca import homomorphism
150
+
151
+ >>> F = QQ.old_poly_ring(x).free_module(2)
152
+ >>> h = homomorphism(F, F, [[1, 0], [x, 0]])
153
+ >>> h
154
+ Matrix([
155
+ [1, x], : QQ[x]**2 -> QQ[x]**2
156
+ [0, 0]])
157
+ >>> h.restrict_domain(F.submodule([1, 0]))
158
+ Matrix([
159
+ [1, x], : <[1, 0]> -> QQ[x]**2
160
+ [0, 0]])
161
+
162
+ This is the same as just composing on the right with the submodule
163
+ inclusion:
164
+
165
+ >>> h * F.submodule([1, 0]).inclusion_hom()
166
+ Matrix([
167
+ [1, x], : <[1, 0]> -> QQ[x]**2
168
+ [0, 0]])
169
+ """
170
+ if not self.domain.is_submodule(sm):
171
+ raise ValueError('sm must be a submodule of %s, got %s'
172
+ % (self.domain, sm))
173
+ if sm == self.domain:
174
+ return self
175
+ return self._restrict_domain(sm)
176
+
177
+ def restrict_codomain(self, sm):
178
+ """
179
+ Return ``self``, with codomain restricted to to ``sm``.
180
+
181
+ Here ``sm`` has to be a submodule of ``self.codomain`` containing the
182
+ image.
183
+
184
+ Examples
185
+ ========
186
+
187
+ >>> from sympy import QQ
188
+ >>> from sympy.abc import x
189
+ >>> from sympy.polys.agca import homomorphism
190
+
191
+ >>> F = QQ.old_poly_ring(x).free_module(2)
192
+ >>> h = homomorphism(F, F, [[1, 0], [x, 0]])
193
+ >>> h
194
+ Matrix([
195
+ [1, x], : QQ[x]**2 -> QQ[x]**2
196
+ [0, 0]])
197
+ >>> h.restrict_codomain(F.submodule([1, 0]))
198
+ Matrix([
199
+ [1, x], : QQ[x]**2 -> <[1, 0]>
200
+ [0, 0]])
201
+ """
202
+ if not sm.is_submodule(self.image()):
203
+ raise ValueError('the image %s must contain sm, got %s'
204
+ % (self.image(), sm))
205
+ if sm == self.codomain:
206
+ return self
207
+ return self._restrict_codomain(sm)
208
+
209
+ def quotient_domain(self, sm):
210
+ """
211
+ Return ``self`` with domain replaced by ``domain/sm``.
212
+
213
+ Here ``sm`` must be a submodule of ``self.kernel()``.
214
+
215
+ Examples
216
+ ========
217
+
218
+ >>> from sympy import QQ
219
+ >>> from sympy.abc import x
220
+ >>> from sympy.polys.agca import homomorphism
221
+
222
+ >>> F = QQ.old_poly_ring(x).free_module(2)
223
+ >>> h = homomorphism(F, F, [[1, 0], [x, 0]])
224
+ >>> h
225
+ Matrix([
226
+ [1, x], : QQ[x]**2 -> QQ[x]**2
227
+ [0, 0]])
228
+ >>> h.quotient_domain(F.submodule([-x, 1]))
229
+ Matrix([
230
+ [1, x], : QQ[x]**2/<[-x, 1]> -> QQ[x]**2
231
+ [0, 0]])
232
+ """
233
+ if not self.kernel().is_submodule(sm):
234
+ raise ValueError('kernel %s must contain sm, got %s' %
235
+ (self.kernel(), sm))
236
+ if sm.is_zero():
237
+ return self
238
+ return self._quotient_domain(sm)
239
+
240
+ def quotient_codomain(self, sm):
241
+ """
242
+ Return ``self`` with codomain replaced by ``codomain/sm``.
243
+
244
+ Here ``sm`` must be a submodule of ``self.codomain``.
245
+
246
+ Examples
247
+ ========
248
+
249
+ >>> from sympy import QQ
250
+ >>> from sympy.abc import x
251
+ >>> from sympy.polys.agca import homomorphism
252
+
253
+ >>> F = QQ.old_poly_ring(x).free_module(2)
254
+ >>> h = homomorphism(F, F, [[1, 0], [x, 0]])
255
+ >>> h
256
+ Matrix([
257
+ [1, x], : QQ[x]**2 -> QQ[x]**2
258
+ [0, 0]])
259
+ >>> h.quotient_codomain(F.submodule([1, 1]))
260
+ Matrix([
261
+ [1, x], : QQ[x]**2 -> QQ[x]**2/<[1, 1]>
262
+ [0, 0]])
263
+
264
+ This is the same as composing with the quotient map on the left:
265
+
266
+ >>> (F/[(1, 1)]).quotient_hom() * h
267
+ Matrix([
268
+ [1, x], : QQ[x]**2 -> QQ[x]**2/<[1, 1]>
269
+ [0, 0]])
270
+ """
271
+ if not self.codomain.is_submodule(sm):
272
+ raise ValueError('sm must be a submodule of codomain %s, got %s'
273
+ % (self.codomain, sm))
274
+ if sm.is_zero():
275
+ return self
276
+ return self._quotient_codomain(sm)
277
+
278
+ def _apply(self, elem):
279
+ """Apply ``self`` to ``elem``."""
280
+ raise NotImplementedError
281
+
282
+ def __call__(self, elem):
283
+ return self.codomain.convert(self._apply(self.domain.convert(elem)))
284
+
285
+ def _compose(self, oth):
286
+ """
287
+ Compose ``self`` with ``oth``, that is, return the homomorphism
288
+ obtained by first applying then ``self``, then ``oth``.
289
+
290
+ (This method is private since in this syntax, it is non-obvious which
291
+ homomorphism is executed first.)
292
+ """
293
+ raise NotImplementedError
294
+
295
+ def _mul_scalar(self, c):
296
+ """Scalar multiplication. ``c`` is guaranteed in self.ring."""
297
+ raise NotImplementedError
298
+
299
+ def _add(self, oth):
300
+ """
301
+ Homomorphism addition.
302
+ ``oth`` is guaranteed to be a homomorphism with same domain/codomain.
303
+ """
304
+ raise NotImplementedError
305
+
306
+ def _check_hom(self, oth):
307
+ """Helper to check that oth is a homomorphism with same domain/codomain."""
308
+ if not isinstance(oth, ModuleHomomorphism):
309
+ return False
310
+ return oth.domain == self.domain and oth.codomain == self.codomain
311
+
312
+ def __mul__(self, oth):
313
+ if isinstance(oth, ModuleHomomorphism) and self.domain == oth.codomain:
314
+ return oth._compose(self)
315
+ try:
316
+ return self._mul_scalar(self.ring.convert(oth))
317
+ except CoercionFailed:
318
+ return NotImplemented
319
+
320
+ # NOTE: _compose will never be called from rmul
321
+ __rmul__ = __mul__
322
+
323
+ def __truediv__(self, oth):
324
+ try:
325
+ return self._mul_scalar(1/self.ring.convert(oth))
326
+ except CoercionFailed:
327
+ return NotImplemented
328
+
329
+ def __add__(self, oth):
330
+ if self._check_hom(oth):
331
+ return self._add(oth)
332
+ return NotImplemented
333
+
334
+ def __sub__(self, oth):
335
+ if self._check_hom(oth):
336
+ return self._add(oth._mul_scalar(self.ring.convert(-1)))
337
+ return NotImplemented
338
+
339
+ def is_injective(self):
340
+ """
341
+ Return True if ``self`` is injective.
342
+
343
+ That is, check if the elements of the domain are mapped to the same
344
+ codomain element.
345
+
346
+ Examples
347
+ ========
348
+
349
+ >>> from sympy import QQ
350
+ >>> from sympy.abc import x
351
+ >>> from sympy.polys.agca import homomorphism
352
+
353
+ >>> F = QQ.old_poly_ring(x).free_module(2)
354
+ >>> h = homomorphism(F, F, [[1, 0], [x, 0]])
355
+ >>> h.is_injective()
356
+ False
357
+ >>> h.quotient_domain(h.kernel()).is_injective()
358
+ True
359
+ """
360
+ return self.kernel().is_zero()
361
+
362
+ def is_surjective(self):
363
+ """
364
+ Return True if ``self`` is surjective.
365
+
366
+ That is, check if every element of the codomain has at least one
367
+ preimage.
368
+
369
+ Examples
370
+ ========
371
+
372
+ >>> from sympy import QQ
373
+ >>> from sympy.abc import x
374
+ >>> from sympy.polys.agca import homomorphism
375
+
376
+ >>> F = QQ.old_poly_ring(x).free_module(2)
377
+ >>> h = homomorphism(F, F, [[1, 0], [x, 0]])
378
+ >>> h.is_surjective()
379
+ False
380
+ >>> h.restrict_codomain(h.image()).is_surjective()
381
+ True
382
+ """
383
+ return self.image() == self.codomain
384
+
385
+ def is_isomorphism(self):
386
+ """
387
+ Return True if ``self`` is an isomorphism.
388
+
389
+ That is, check if every element of the codomain has precisely one
390
+ preimage. Equivalently, ``self`` is both injective and surjective.
391
+
392
+ Examples
393
+ ========
394
+
395
+ >>> from sympy import QQ
396
+ >>> from sympy.abc import x
397
+ >>> from sympy.polys.agca import homomorphism
398
+
399
+ >>> F = QQ.old_poly_ring(x).free_module(2)
400
+ >>> h = homomorphism(F, F, [[1, 0], [x, 0]])
401
+ >>> h = h.restrict_codomain(h.image())
402
+ >>> h.is_isomorphism()
403
+ False
404
+ >>> h.quotient_domain(h.kernel()).is_isomorphism()
405
+ True
406
+ """
407
+ return self.is_injective() and self.is_surjective()
408
+
409
+ def is_zero(self):
410
+ """
411
+ Return True if ``self`` is a zero morphism.
412
+
413
+ That is, check if every element of the domain is mapped to zero
414
+ under self.
415
+
416
+ Examples
417
+ ========
418
+
419
+ >>> from sympy import QQ
420
+ >>> from sympy.abc import x
421
+ >>> from sympy.polys.agca import homomorphism
422
+
423
+ >>> F = QQ.old_poly_ring(x).free_module(2)
424
+ >>> h = homomorphism(F, F, [[1, 0], [x, 0]])
425
+ >>> h.is_zero()
426
+ False
427
+ >>> h.restrict_domain(F.submodule()).is_zero()
428
+ True
429
+ >>> h.quotient_codomain(h.image()).is_zero()
430
+ True
431
+ """
432
+ return self.image().is_zero()
433
+
434
+ def __eq__(self, oth):
435
+ try:
436
+ return (self - oth).is_zero()
437
+ except TypeError:
438
+ return False
439
+
440
+ def __ne__(self, oth):
441
+ return not (self == oth)
442
+
443
+
444
+ class MatrixHomomorphism(ModuleHomomorphism):
445
+ r"""
446
+ Helper class for all homomoprhisms which are expressed via a matrix.
447
+
448
+ That is, for such homomorphisms ``domain`` is contained in a module
449
+ generated by finitely many elements `e_1, \ldots, e_n`, so that the
450
+ homomorphism is determined uniquely by its action on the `e_i`. It
451
+ can thus be represented as a vector of elements of the codomain module,
452
+ or potentially a supermodule of the codomain module
453
+ (and hence conventionally as a matrix, if there is a similar interpretation
454
+ for elements of the codomain module).
455
+
456
+ Note that this class does *not* assume that the `e_i` freely generate a
457
+ submodule, nor that ``domain`` is even all of this submodule. It exists
458
+ only to unify the interface.
459
+
460
+ Do not instantiate.
461
+
462
+ Attributes:
463
+
464
+ - matrix - the list of images determining the homomorphism.
465
+ NOTE: the elements of matrix belong to either self.codomain or
466
+ self.codomain.container
467
+
468
+ Still non-implemented methods:
469
+
470
+ - kernel
471
+ - _apply
472
+ """
473
+
474
+ def __init__(self, domain, codomain, matrix):
475
+ ModuleHomomorphism.__init__(self, domain, codomain)
476
+ if len(matrix) != domain.rank:
477
+ raise ValueError('Need to provide %s elements, got %s'
478
+ % (domain.rank, len(matrix)))
479
+
480
+ converter = self.codomain.convert
481
+ if isinstance(self.codomain, (SubModule, SubQuotientModule)):
482
+ converter = self.codomain.container.convert
483
+ self.matrix = tuple(converter(x) for x in matrix)
484
+
485
+ def _sympy_matrix(self):
486
+ """Helper function which returns a SymPy matrix ``self.matrix``."""
487
+ from sympy.matrices import Matrix
488
+ c = lambda x: x
489
+ if isinstance(self.codomain, (QuotientModule, SubQuotientModule)):
490
+ c = lambda x: x.data
491
+ return Matrix([[self.ring.to_sympy(y) for y in c(x)] for x in self.matrix]).T
492
+
493
+ def __repr__(self):
494
+ lines = repr(self._sympy_matrix()).split('\n')
495
+ t = " : %s -> %s" % (self.domain, self.codomain)
496
+ s = ' '*len(t)
497
+ n = len(lines)
498
+ for i in range(n // 2):
499
+ lines[i] += s
500
+ lines[n // 2] += t
501
+ for i in range(n//2 + 1, n):
502
+ lines[i] += s
503
+ return '\n'.join(lines)
504
+
505
+ def _restrict_domain(self, sm):
506
+ """Implementation of domain restriction."""
507
+ return SubModuleHomomorphism(sm, self.codomain, self.matrix)
508
+
509
+ def _restrict_codomain(self, sm):
510
+ """Implementation of codomain restriction."""
511
+ return self.__class__(self.domain, sm, self.matrix)
512
+
513
+ def _quotient_domain(self, sm):
514
+ """Implementation of domain quotient."""
515
+ return self.__class__(self.domain/sm, self.codomain, self.matrix)
516
+
517
+ def _quotient_codomain(self, sm):
518
+ """Implementation of codomain quotient."""
519
+ Q = self.codomain/sm
520
+ converter = Q.convert
521
+ if isinstance(self.codomain, SubModule):
522
+ converter = Q.container.convert
523
+ return self.__class__(self.domain, self.codomain/sm,
524
+ [converter(x) for x in self.matrix])
525
+
526
+ def _add(self, oth):
527
+ return self.__class__(self.domain, self.codomain,
528
+ [x + y for x, y in zip(self.matrix, oth.matrix)])
529
+
530
+ def _mul_scalar(self, c):
531
+ return self.__class__(self.domain, self.codomain, [c*x for x in self.matrix])
532
+
533
+ def _compose(self, oth):
534
+ return self.__class__(self.domain, oth.codomain, [oth(x) for x in self.matrix])
535
+
536
+
537
+ class FreeModuleHomomorphism(MatrixHomomorphism):
538
+ """
539
+ Concrete class for homomorphisms with domain a free module or a quotient
540
+ thereof.
541
+
542
+ Do not instantiate; the constructor does not check that your data is well
543
+ defined. Use the ``homomorphism`` function instead:
544
+
545
+ >>> from sympy import QQ
546
+ >>> from sympy.abc import x
547
+ >>> from sympy.polys.agca import homomorphism
548
+
549
+ >>> F = QQ.old_poly_ring(x).free_module(2)
550
+ >>> homomorphism(F, F, [[1, 0], [0, 1]])
551
+ Matrix([
552
+ [1, 0], : QQ[x]**2 -> QQ[x]**2
553
+ [0, 1]])
554
+ """
555
+
556
+ def _apply(self, elem):
557
+ if isinstance(self.domain, QuotientModule):
558
+ elem = elem.data
559
+ return sum(x * e for x, e in zip(elem, self.matrix))
560
+
561
+ def _image(self):
562
+ return self.codomain.submodule(*self.matrix)
563
+
564
+ def _kernel(self):
565
+ # The domain is either a free module or a quotient thereof.
566
+ # It does not matter if it is a quotient, because that won't increase
567
+ # the kernel.
568
+ # Our generators {e_i} are sent to the matrix entries {b_i}.
569
+ # The kernel is essentially the syzygy module of these {b_i}.
570
+ syz = self.image().syzygy_module()
571
+ return self.domain.submodule(*syz.gens)
572
+
573
+
574
+ class SubModuleHomomorphism(MatrixHomomorphism):
575
+ """
576
+ Concrete class for homomorphism with domain a submodule of a free module
577
+ or a quotient thereof.
578
+
579
+ Do not instantiate; the constructor does not check that your data is well
580
+ defined. Use the ``homomorphism`` function instead:
581
+
582
+ >>> from sympy import QQ
583
+ >>> from sympy.abc import x
584
+ >>> from sympy.polys.agca import homomorphism
585
+
586
+ >>> M = QQ.old_poly_ring(x).free_module(2)*x
587
+ >>> homomorphism(M, M, [[1, 0], [0, 1]])
588
+ Matrix([
589
+ [1, 0], : <[x, 0], [0, x]> -> <[x, 0], [0, x]>
590
+ [0, 1]])
591
+ """
592
+
593
+ def _apply(self, elem):
594
+ if isinstance(self.domain, SubQuotientModule):
595
+ elem = elem.data
596
+ return sum(x * e for x, e in zip(elem, self.matrix))
597
+
598
+ def _image(self):
599
+ return self.codomain.submodule(*[self(x) for x in self.domain.gens])
600
+
601
+ def _kernel(self):
602
+ syz = self.image().syzygy_module()
603
+ return self.domain.submodule(
604
+ *[sum(xi*gi for xi, gi in zip(s, self.domain.gens))
605
+ for s in syz.gens])
606
+
607
+
608
+ def homomorphism(domain, codomain, matrix):
609
+ r"""
610
+ Create a homomorphism object.
611
+
612
+ This function tries to build a homomorphism from ``domain`` to ``codomain``
613
+ via the matrix ``matrix``.
614
+
615
+ Examples
616
+ ========
617
+
618
+ >>> from sympy import QQ
619
+ >>> from sympy.abc import x
620
+ >>> from sympy.polys.agca import homomorphism
621
+
622
+ >>> R = QQ.old_poly_ring(x)
623
+ >>> T = R.free_module(2)
624
+
625
+ If ``domain`` is a free module generated by `e_1, \ldots, e_n`, then
626
+ ``matrix`` should be an n-element iterable `(b_1, \ldots, b_n)` where
627
+ the `b_i` are elements of ``codomain``. The constructed homomorphism is the
628
+ unique homomorphism sending `e_i` to `b_i`.
629
+
630
+ >>> F = R.free_module(2)
631
+ >>> h = homomorphism(F, T, [[1, x], [x**2, 0]])
632
+ >>> h
633
+ Matrix([
634
+ [1, x**2], : QQ[x]**2 -> QQ[x]**2
635
+ [x, 0]])
636
+ >>> h([1, 0])
637
+ [1, x]
638
+ >>> h([0, 1])
639
+ [x**2, 0]
640
+ >>> h([1, 1])
641
+ [x**2 + 1, x]
642
+
643
+ If ``domain`` is a submodule of a free module, them ``matrix`` determines
644
+ a homomoprhism from the containing free module to ``codomain``, and the
645
+ homomorphism returned is obtained by restriction to ``domain``.
646
+
647
+ >>> S = F.submodule([1, 0], [0, x])
648
+ >>> homomorphism(S, T, [[1, x], [x**2, 0]])
649
+ Matrix([
650
+ [1, x**2], : <[1, 0], [0, x]> -> QQ[x]**2
651
+ [x, 0]])
652
+
653
+ If ``domain`` is a (sub)quotient `N/K`, then ``matrix`` determines a
654
+ homomorphism from `N` to ``codomain``. If the kernel contains `K`, this
655
+ homomorphism descends to ``domain`` and is returned; otherwise an exception
656
+ is raised.
657
+
658
+ >>> homomorphism(S/[(1, 0)], T, [0, [x**2, 0]])
659
+ Matrix([
660
+ [0, x**2], : <[1, 0] + <[1, 0]>, [0, x] + <[1, 0]>, [1, 0] + <[1, 0]>> -> QQ[x]**2
661
+ [0, 0]])
662
+ >>> homomorphism(S/[(0, x)], T, [0, [x**2, 0]])
663
+ Traceback (most recent call last):
664
+ ...
665
+ ValueError: kernel <[1, 0], [0, 0]> must contain sm, got <[0,x]>
666
+
667
+ """
668
+ def freepres(module):
669
+ """
670
+ Return a tuple ``(F, S, Q, c)`` where ``F`` is a free module, ``S`` is a
671
+ submodule of ``F``, and ``Q`` a submodule of ``S``, such that
672
+ ``module = S/Q``, and ``c`` is a conversion function.
673
+ """
674
+ if isinstance(module, FreeModule):
675
+ return module, module, module.submodule(), lambda x: module.convert(x)
676
+ if isinstance(module, QuotientModule):
677
+ return (module.base, module.base, module.killed_module,
678
+ lambda x: module.convert(x).data)
679
+ if isinstance(module, SubQuotientModule):
680
+ return (module.base.container, module.base, module.killed_module,
681
+ lambda x: module.container.convert(x).data)
682
+ # an ordinary submodule
683
+ return (module.container, module, module.submodule(),
684
+ lambda x: module.container.convert(x))
685
+
686
+ SF, SS, SQ, _ = freepres(domain)
687
+ TF, TS, TQ, c = freepres(codomain)
688
+ # NOTE this is probably a bit inefficient (redundant checks)
689
+ return FreeModuleHomomorphism(SF, TF, [c(x) for x in matrix]
690
+ ).restrict_domain(SS).restrict_codomain(TS
691
+ ).quotient_codomain(TQ).quotient_domain(SQ)
llmeval-env/lib/python3.10/site-packages/sympy/polys/agca/ideals.py ADDED
@@ -0,0 +1,394 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ """Computations with ideals of polynomial rings."""
2
+
3
+ from sympy.polys.polyerrors import CoercionFailed
4
+ from sympy.polys.polyutils import IntegerPowerable
5
+
6
+
7
+ class Ideal(IntegerPowerable):
8
+ """
9
+ Abstract base class for ideals.
10
+
11
+ Do not instantiate - use explicit constructors in the ring class instead:
12
+
13
+ >>> from sympy import QQ
14
+ >>> from sympy.abc import x
15
+ >>> QQ.old_poly_ring(x).ideal(x+1)
16
+ <x + 1>
17
+
18
+ Attributes
19
+
20
+ - ring - the ring this ideal belongs to
21
+
22
+ Non-implemented methods:
23
+
24
+ - _contains_elem
25
+ - _contains_ideal
26
+ - _quotient
27
+ - _intersect
28
+ - _union
29
+ - _product
30
+ - is_whole_ring
31
+ - is_zero
32
+ - is_prime, is_maximal, is_primary, is_radical
33
+ - is_principal
34
+ - height, depth
35
+ - radical
36
+
37
+ Methods that likely should be overridden in subclasses:
38
+
39
+ - reduce_element
40
+ """
41
+
42
+ def _contains_elem(self, x):
43
+ """Implementation of element containment."""
44
+ raise NotImplementedError
45
+
46
+ def _contains_ideal(self, I):
47
+ """Implementation of ideal containment."""
48
+ raise NotImplementedError
49
+
50
+ def _quotient(self, J):
51
+ """Implementation of ideal quotient."""
52
+ raise NotImplementedError
53
+
54
+ def _intersect(self, J):
55
+ """Implementation of ideal intersection."""
56
+ raise NotImplementedError
57
+
58
+ def is_whole_ring(self):
59
+ """Return True if ``self`` is the whole ring."""
60
+ raise NotImplementedError
61
+
62
+ def is_zero(self):
63
+ """Return True if ``self`` is the zero ideal."""
64
+ raise NotImplementedError
65
+
66
+ def _equals(self, J):
67
+ """Implementation of ideal equality."""
68
+ return self._contains_ideal(J) and J._contains_ideal(self)
69
+
70
+ def is_prime(self):
71
+ """Return True if ``self`` is a prime ideal."""
72
+ raise NotImplementedError
73
+
74
+ def is_maximal(self):
75
+ """Return True if ``self`` is a maximal ideal."""
76
+ raise NotImplementedError
77
+
78
+ def is_radical(self):
79
+ """Return True if ``self`` is a radical ideal."""
80
+ raise NotImplementedError
81
+
82
+ def is_primary(self):
83
+ """Return True if ``self`` is a primary ideal."""
84
+ raise NotImplementedError
85
+
86
+ def is_principal(self):
87
+ """Return True if ``self`` is a principal ideal."""
88
+ raise NotImplementedError
89
+
90
+ def radical(self):
91
+ """Compute the radical of ``self``."""
92
+ raise NotImplementedError
93
+
94
+ def depth(self):
95
+ """Compute the depth of ``self``."""
96
+ raise NotImplementedError
97
+
98
+ def height(self):
99
+ """Compute the height of ``self``."""
100
+ raise NotImplementedError
101
+
102
+ # TODO more
103
+
104
+ # non-implemented methods end here
105
+
106
+ def __init__(self, ring):
107
+ self.ring = ring
108
+
109
+ def _check_ideal(self, J):
110
+ """Helper to check ``J`` is an ideal of our ring."""
111
+ if not isinstance(J, Ideal) or J.ring != self.ring:
112
+ raise ValueError(
113
+ 'J must be an ideal of %s, got %s' % (self.ring, J))
114
+
115
+ def contains(self, elem):
116
+ """
117
+ Return True if ``elem`` is an element of this ideal.
118
+
119
+ Examples
120
+ ========
121
+
122
+ >>> from sympy.abc import x
123
+ >>> from sympy import QQ
124
+ >>> QQ.old_poly_ring(x).ideal(x+1, x-1).contains(3)
125
+ True
126
+ >>> QQ.old_poly_ring(x).ideal(x**2, x**3).contains(x)
127
+ False
128
+ """
129
+ return self._contains_elem(self.ring.convert(elem))
130
+
131
+ def subset(self, other):
132
+ """
133
+ Returns True if ``other`` is is a subset of ``self``.
134
+
135
+ Here ``other`` may be an ideal.
136
+
137
+ Examples
138
+ ========
139
+
140
+ >>> from sympy.abc import x
141
+ >>> from sympy import QQ
142
+ >>> I = QQ.old_poly_ring(x).ideal(x+1)
143
+ >>> I.subset([x**2 - 1, x**2 + 2*x + 1])
144
+ True
145
+ >>> I.subset([x**2 + 1, x + 1])
146
+ False
147
+ >>> I.subset(QQ.old_poly_ring(x).ideal(x**2 - 1))
148
+ True
149
+ """
150
+ if isinstance(other, Ideal):
151
+ return self._contains_ideal(other)
152
+ return all(self._contains_elem(x) for x in other)
153
+
154
+ def quotient(self, J, **opts):
155
+ r"""
156
+ Compute the ideal quotient of ``self`` by ``J``.
157
+
158
+ That is, if ``self`` is the ideal `I`, compute the set
159
+ `I : J = \{x \in R | xJ \subset I \}`.
160
+
161
+ Examples
162
+ ========
163
+
164
+ >>> from sympy.abc import x, y
165
+ >>> from sympy import QQ
166
+ >>> R = QQ.old_poly_ring(x, y)
167
+ >>> R.ideal(x*y).quotient(R.ideal(x))
168
+ <y>
169
+ """
170
+ self._check_ideal(J)
171
+ return self._quotient(J, **opts)
172
+
173
+ def intersect(self, J):
174
+ """
175
+ Compute the intersection of self with ideal J.
176
+
177
+ Examples
178
+ ========
179
+
180
+ >>> from sympy.abc import x, y
181
+ >>> from sympy import QQ
182
+ >>> R = QQ.old_poly_ring(x, y)
183
+ >>> R.ideal(x).intersect(R.ideal(y))
184
+ <x*y>
185
+ """
186
+ self._check_ideal(J)
187
+ return self._intersect(J)
188
+
189
+ def saturate(self, J):
190
+ r"""
191
+ Compute the ideal saturation of ``self`` by ``J``.
192
+
193
+ That is, if ``self`` is the ideal `I`, compute the set
194
+ `I : J^\infty = \{x \in R | xJ^n \subset I \text{ for some } n\}`.
195
+ """
196
+ raise NotImplementedError
197
+ # Note this can be implemented using repeated quotient
198
+
199
+ def union(self, J):
200
+ """
201
+ Compute the ideal generated by the union of ``self`` and ``J``.
202
+
203
+ Examples
204
+ ========
205
+
206
+ >>> from sympy.abc import x
207
+ >>> from sympy import QQ
208
+ >>> QQ.old_poly_ring(x).ideal(x**2 - 1).union(QQ.old_poly_ring(x).ideal((x+1)**2)) == QQ.old_poly_ring(x).ideal(x+1)
209
+ True
210
+ """
211
+ self._check_ideal(J)
212
+ return self._union(J)
213
+
214
+ def product(self, J):
215
+ r"""
216
+ Compute the ideal product of ``self`` and ``J``.
217
+
218
+ That is, compute the ideal generated by products `xy`, for `x` an element
219
+ of ``self`` and `y \in J`.
220
+
221
+ Examples
222
+ ========
223
+
224
+ >>> from sympy.abc import x, y
225
+ >>> from sympy import QQ
226
+ >>> QQ.old_poly_ring(x, y).ideal(x).product(QQ.old_poly_ring(x, y).ideal(y))
227
+ <x*y>
228
+ """
229
+ self._check_ideal(J)
230
+ return self._product(J)
231
+
232
+ def reduce_element(self, x):
233
+ """
234
+ Reduce the element ``x`` of our ring modulo the ideal ``self``.
235
+
236
+ Here "reduce" has no specific meaning: it could return a unique normal
237
+ form, simplify the expression a bit, or just do nothing.
238
+ """
239
+ return x
240
+
241
+ def __add__(self, e):
242
+ if not isinstance(e, Ideal):
243
+ R = self.ring.quotient_ring(self)
244
+ if isinstance(e, R.dtype):
245
+ return e
246
+ if isinstance(e, R.ring.dtype):
247
+ return R(e)
248
+ return R.convert(e)
249
+ self._check_ideal(e)
250
+ return self.union(e)
251
+
252
+ __radd__ = __add__
253
+
254
+ def __mul__(self, e):
255
+ if not isinstance(e, Ideal):
256
+ try:
257
+ e = self.ring.ideal(e)
258
+ except CoercionFailed:
259
+ return NotImplemented
260
+ self._check_ideal(e)
261
+ return self.product(e)
262
+
263
+ __rmul__ = __mul__
264
+
265
+ def _zeroth_power(self):
266
+ return self.ring.ideal(1)
267
+
268
+ def _first_power(self):
269
+ # Raising to any power but 1 returns a new instance. So we mult by 1
270
+ # here so that the first power is no exception.
271
+ return self * 1
272
+
273
+ def __eq__(self, e):
274
+ if not isinstance(e, Ideal) or e.ring != self.ring:
275
+ return False
276
+ return self._equals(e)
277
+
278
+ def __ne__(self, e):
279
+ return not (self == e)
280
+
281
+
282
+ class ModuleImplementedIdeal(Ideal):
283
+ """
284
+ Ideal implementation relying on the modules code.
285
+
286
+ Attributes:
287
+
288
+ - _module - the underlying module
289
+ """
290
+
291
+ def __init__(self, ring, module):
292
+ Ideal.__init__(self, ring)
293
+ self._module = module
294
+
295
+ def _contains_elem(self, x):
296
+ return self._module.contains([x])
297
+
298
+ def _contains_ideal(self, J):
299
+ if not isinstance(J, ModuleImplementedIdeal):
300
+ raise NotImplementedError
301
+ return self._module.is_submodule(J._module)
302
+
303
+ def _intersect(self, J):
304
+ if not isinstance(J, ModuleImplementedIdeal):
305
+ raise NotImplementedError
306
+ return self.__class__(self.ring, self._module.intersect(J._module))
307
+
308
+ def _quotient(self, J, **opts):
309
+ if not isinstance(J, ModuleImplementedIdeal):
310
+ raise NotImplementedError
311
+ return self._module.module_quotient(J._module, **opts)
312
+
313
+ def _union(self, J):
314
+ if not isinstance(J, ModuleImplementedIdeal):
315
+ raise NotImplementedError
316
+ return self.__class__(self.ring, self._module.union(J._module))
317
+
318
+ @property
319
+ def gens(self):
320
+ """
321
+ Return generators for ``self``.
322
+
323
+ Examples
324
+ ========
325
+
326
+ >>> from sympy import QQ
327
+ >>> from sympy.abc import x, y
328
+ >>> list(QQ.old_poly_ring(x, y).ideal(x, y, x**2 + y).gens)
329
+ [x, y, x**2 + y]
330
+ """
331
+ return (x[0] for x in self._module.gens)
332
+
333
+ def is_zero(self):
334
+ """
335
+ Return True if ``self`` is the zero ideal.
336
+
337
+ Examples
338
+ ========
339
+
340
+ >>> from sympy.abc import x
341
+ >>> from sympy import QQ
342
+ >>> QQ.old_poly_ring(x).ideal(x).is_zero()
343
+ False
344
+ >>> QQ.old_poly_ring(x).ideal().is_zero()
345
+ True
346
+ """
347
+ return self._module.is_zero()
348
+
349
+ def is_whole_ring(self):
350
+ """
351
+ Return True if ``self`` is the whole ring, i.e. one generator is a unit.
352
+
353
+ Examples
354
+ ========
355
+
356
+ >>> from sympy.abc import x
357
+ >>> from sympy import QQ, ilex
358
+ >>> QQ.old_poly_ring(x).ideal(x).is_whole_ring()
359
+ False
360
+ >>> QQ.old_poly_ring(x).ideal(3).is_whole_ring()
361
+ True
362
+ >>> QQ.old_poly_ring(x, order=ilex).ideal(2 + x).is_whole_ring()
363
+ True
364
+ """
365
+ return self._module.is_full_module()
366
+
367
+ def __repr__(self):
368
+ from sympy.printing.str import sstr
369
+ return '<' + ','.join(sstr(x) for [x] in self._module.gens) + '>'
370
+
371
+ # NOTE this is the only method using the fact that the module is a SubModule
372
+ def _product(self, J):
373
+ if not isinstance(J, ModuleImplementedIdeal):
374
+ raise NotImplementedError
375
+ return self.__class__(self.ring, self._module.submodule(
376
+ *[[x*y] for [x] in self._module.gens for [y] in J._module.gens]))
377
+
378
+ def in_terms_of_generators(self, e):
379
+ """
380
+ Express ``e`` in terms of the generators of ``self``.
381
+
382
+ Examples
383
+ ========
384
+
385
+ >>> from sympy.abc import x
386
+ >>> from sympy import QQ
387
+ >>> I = QQ.old_poly_ring(x).ideal(x**2 + 1, x)
388
+ >>> I.in_terms_of_generators(1)
389
+ [1, -x]
390
+ """
391
+ return self._module.in_terms_of_generators([e])
392
+
393
+ def reduce_element(self, x, **options):
394
+ return self._module.reduce_element([x], **options)[0]
llmeval-env/lib/python3.10/site-packages/sympy/polys/agca/modules.py ADDED
@@ -0,0 +1,1484 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ """
2
+ Computations with modules over polynomial rings.
3
+
4
+ This module implements various classes that encapsulate groebner basis
5
+ computations for modules. Most of them should not be instantiated by hand.
6
+ Instead, use the constructing routines on objects you already have.
7
+
8
+ For example, to construct a free module over ``QQ[x, y]``, call
9
+ ``QQ[x, y].free_module(rank)`` instead of the ``FreeModule`` constructor.
10
+ In fact ``FreeModule`` is an abstract base class that should not be
11
+ instantiated, the ``free_module`` method instead returns the implementing class
12
+ ``FreeModulePolyRing``.
13
+
14
+ In general, the abstract base classes implement most functionality in terms of
15
+ a few non-implemented methods. The concrete base classes supply only these
16
+ non-implemented methods. They may also supply new implementations of the
17
+ convenience methods, for example if there are faster algorithms available.
18
+ """
19
+
20
+
21
+ from copy import copy
22
+ from functools import reduce
23
+
24
+ from sympy.polys.agca.ideals import Ideal
25
+ from sympy.polys.domains.field import Field
26
+ from sympy.polys.orderings import ProductOrder, monomial_key
27
+ from sympy.polys.polyerrors import CoercionFailed
28
+ from sympy.core.basic import _aresame
29
+ from sympy.utilities.iterables import iterable
30
+
31
+ # TODO
32
+ # - module saturation
33
+ # - module quotient/intersection for quotient rings
34
+ # - free resoltutions / syzygies
35
+ # - finding small/minimal generating sets
36
+ # - ...
37
+
38
+ ##########################################################################
39
+ ## Abstract base classes #################################################
40
+ ##########################################################################
41
+
42
+
43
+ class Module:
44
+ """
45
+ Abstract base class for modules.
46
+
47
+ Do not instantiate - use ring explicit constructors instead:
48
+
49
+ >>> from sympy import QQ
50
+ >>> from sympy.abc import x
51
+ >>> QQ.old_poly_ring(x).free_module(2)
52
+ QQ[x]**2
53
+
54
+ Attributes:
55
+
56
+ - dtype - type of elements
57
+ - ring - containing ring
58
+
59
+ Non-implemented methods:
60
+
61
+ - submodule
62
+ - quotient_module
63
+ - is_zero
64
+ - is_submodule
65
+ - multiply_ideal
66
+
67
+ The method convert likely needs to be changed in subclasses.
68
+ """
69
+
70
+ def __init__(self, ring):
71
+ self.ring = ring
72
+
73
+ def convert(self, elem, M=None):
74
+ """
75
+ Convert ``elem`` into internal representation of this module.
76
+
77
+ If ``M`` is not None, it should be a module containing it.
78
+ """
79
+ if not isinstance(elem, self.dtype):
80
+ raise CoercionFailed
81
+ return elem
82
+
83
+ def submodule(self, *gens):
84
+ """Generate a submodule."""
85
+ raise NotImplementedError
86
+
87
+ def quotient_module(self, other):
88
+ """Generate a quotient module."""
89
+ raise NotImplementedError
90
+
91
+ def __truediv__(self, e):
92
+ if not isinstance(e, Module):
93
+ e = self.submodule(*e)
94
+ return self.quotient_module(e)
95
+
96
+ def contains(self, elem):
97
+ """Return True if ``elem`` is an element of this module."""
98
+ try:
99
+ self.convert(elem)
100
+ return True
101
+ except CoercionFailed:
102
+ return False
103
+
104
+ def __contains__(self, elem):
105
+ return self.contains(elem)
106
+
107
+ def subset(self, other):
108
+ """
109
+ Returns True if ``other`` is is a subset of ``self``.
110
+
111
+ Examples
112
+ ========
113
+
114
+ >>> from sympy.abc import x
115
+ >>> from sympy import QQ
116
+ >>> F = QQ.old_poly_ring(x).free_module(2)
117
+ >>> F.subset([(1, x), (x, 2)])
118
+ True
119
+ >>> F.subset([(1/x, x), (x, 2)])
120
+ False
121
+ """
122
+ return all(self.contains(x) for x in other)
123
+
124
+ def __eq__(self, other):
125
+ return self.is_submodule(other) and other.is_submodule(self)
126
+
127
+ def __ne__(self, other):
128
+ return not (self == other)
129
+
130
+ def is_zero(self):
131
+ """Returns True if ``self`` is a zero module."""
132
+ raise NotImplementedError
133
+
134
+ def is_submodule(self, other):
135
+ """Returns True if ``other`` is a submodule of ``self``."""
136
+ raise NotImplementedError
137
+
138
+ def multiply_ideal(self, other):
139
+ """
140
+ Multiply ``self`` by the ideal ``other``.
141
+ """
142
+ raise NotImplementedError
143
+
144
+ def __mul__(self, e):
145
+ if not isinstance(e, Ideal):
146
+ try:
147
+ e = self.ring.ideal(e)
148
+ except (CoercionFailed, NotImplementedError):
149
+ return NotImplemented
150
+ return self.multiply_ideal(e)
151
+
152
+ __rmul__ = __mul__
153
+
154
+ def identity_hom(self):
155
+ """Return the identity homomorphism on ``self``."""
156
+ raise NotImplementedError
157
+
158
+
159
+ class ModuleElement:
160
+ """
161
+ Base class for module element wrappers.
162
+
163
+ Use this class to wrap primitive data types as module elements. It stores
164
+ a reference to the containing module, and implements all the arithmetic
165
+ operators.
166
+
167
+ Attributes:
168
+
169
+ - module - containing module
170
+ - data - internal data
171
+
172
+ Methods that likely need change in subclasses:
173
+
174
+ - add
175
+ - mul
176
+ - div
177
+ - eq
178
+ """
179
+
180
+ def __init__(self, module, data):
181
+ self.module = module
182
+ self.data = data
183
+
184
+ def add(self, d1, d2):
185
+ """Add data ``d1`` and ``d2``."""
186
+ return d1 + d2
187
+
188
+ def mul(self, m, d):
189
+ """Multiply module data ``m`` by coefficient d."""
190
+ return m * d
191
+
192
+ def div(self, m, d):
193
+ """Divide module data ``m`` by coefficient d."""
194
+ return m / d
195
+
196
+ def eq(self, d1, d2):
197
+ """Return true if d1 and d2 represent the same element."""
198
+ return d1 == d2
199
+
200
+ def __add__(self, om):
201
+ if not isinstance(om, self.__class__) or om.module != self.module:
202
+ try:
203
+ om = self.module.convert(om)
204
+ except CoercionFailed:
205
+ return NotImplemented
206
+ return self.__class__(self.module, self.add(self.data, om.data))
207
+
208
+ __radd__ = __add__
209
+
210
+ def __neg__(self):
211
+ return self.__class__(self.module, self.mul(self.data,
212
+ self.module.ring.convert(-1)))
213
+
214
+ def __sub__(self, om):
215
+ if not isinstance(om, self.__class__) or om.module != self.module:
216
+ try:
217
+ om = self.module.convert(om)
218
+ except CoercionFailed:
219
+ return NotImplemented
220
+ return self.__add__(-om)
221
+
222
+ def __rsub__(self, om):
223
+ return (-self).__add__(om)
224
+
225
+ def __mul__(self, o):
226
+ if not isinstance(o, self.module.ring.dtype):
227
+ try:
228
+ o = self.module.ring.convert(o)
229
+ except CoercionFailed:
230
+ return NotImplemented
231
+ return self.__class__(self.module, self.mul(self.data, o))
232
+
233
+ __rmul__ = __mul__
234
+
235
+ def __truediv__(self, o):
236
+ if not isinstance(o, self.module.ring.dtype):
237
+ try:
238
+ o = self.module.ring.convert(o)
239
+ except CoercionFailed:
240
+ return NotImplemented
241
+ return self.__class__(self.module, self.div(self.data, o))
242
+
243
+ def __eq__(self, om):
244
+ if not isinstance(om, self.__class__) or om.module != self.module:
245
+ try:
246
+ om = self.module.convert(om)
247
+ except CoercionFailed:
248
+ return False
249
+ return self.eq(self.data, om.data)
250
+
251
+ def __ne__(self, om):
252
+ return not self == om
253
+
254
+ ##########################################################################
255
+ ## Free Modules ##########################################################
256
+ ##########################################################################
257
+
258
+
259
+ class FreeModuleElement(ModuleElement):
260
+ """Element of a free module. Data stored as a tuple."""
261
+
262
+ def add(self, d1, d2):
263
+ return tuple(x + y for x, y in zip(d1, d2))
264
+
265
+ def mul(self, d, p):
266
+ return tuple(x * p for x in d)
267
+
268
+ def div(self, d, p):
269
+ return tuple(x / p for x in d)
270
+
271
+ def __repr__(self):
272
+ from sympy.printing.str import sstr
273
+ return '[' + ', '.join(sstr(x) for x in self.data) + ']'
274
+
275
+ def __iter__(self):
276
+ return self.data.__iter__()
277
+
278
+ def __getitem__(self, idx):
279
+ return self.data[idx]
280
+
281
+
282
+ class FreeModule(Module):
283
+ """
284
+ Abstract base class for free modules.
285
+
286
+ Additional attributes:
287
+
288
+ - rank - rank of the free module
289
+
290
+ Non-implemented methods:
291
+
292
+ - submodule
293
+ """
294
+
295
+ dtype = FreeModuleElement
296
+
297
+ def __init__(self, ring, rank):
298
+ Module.__init__(self, ring)
299
+ self.rank = rank
300
+
301
+ def __repr__(self):
302
+ return repr(self.ring) + "**" + repr(self.rank)
303
+
304
+ def is_submodule(self, other):
305
+ """
306
+ Returns True if ``other`` is a submodule of ``self``.
307
+
308
+ Examples
309
+ ========
310
+
311
+ >>> from sympy.abc import x
312
+ >>> from sympy import QQ
313
+ >>> F = QQ.old_poly_ring(x).free_module(2)
314
+ >>> M = F.submodule([2, x])
315
+ >>> F.is_submodule(F)
316
+ True
317
+ >>> F.is_submodule(M)
318
+ True
319
+ >>> M.is_submodule(F)
320
+ False
321
+ """
322
+ if isinstance(other, SubModule):
323
+ return other.container == self
324
+ if isinstance(other, FreeModule):
325
+ return other.ring == self.ring and other.rank == self.rank
326
+ return False
327
+
328
+ def convert(self, elem, M=None):
329
+ """
330
+ Convert ``elem`` into the internal representation.
331
+
332
+ This method is called implicitly whenever computations involve elements
333
+ not in the internal representation.
334
+
335
+ Examples
336
+ ========
337
+
338
+ >>> from sympy.abc import x
339
+ >>> from sympy import QQ
340
+ >>> F = QQ.old_poly_ring(x).free_module(2)
341
+ >>> F.convert([1, 0])
342
+ [1, 0]
343
+ """
344
+ if isinstance(elem, FreeModuleElement):
345
+ if elem.module is self:
346
+ return elem
347
+ if elem.module.rank != self.rank:
348
+ raise CoercionFailed
349
+ return FreeModuleElement(self,
350
+ tuple(self.ring.convert(x, elem.module.ring) for x in elem.data))
351
+ elif iterable(elem):
352
+ tpl = tuple(self.ring.convert(x) for x in elem)
353
+ if len(tpl) != self.rank:
354
+ raise CoercionFailed
355
+ return FreeModuleElement(self, tpl)
356
+ elif _aresame(elem, 0):
357
+ return FreeModuleElement(self, (self.ring.convert(0),)*self.rank)
358
+ else:
359
+ raise CoercionFailed
360
+
361
+ def is_zero(self):
362
+ """
363
+ Returns True if ``self`` is a zero module.
364
+
365
+ (If, as this implementation assumes, the coefficient ring is not the
366
+ zero ring, then this is equivalent to the rank being zero.)
367
+
368
+ Examples
369
+ ========
370
+
371
+ >>> from sympy.abc import x
372
+ >>> from sympy import QQ
373
+ >>> QQ.old_poly_ring(x).free_module(0).is_zero()
374
+ True
375
+ >>> QQ.old_poly_ring(x).free_module(1).is_zero()
376
+ False
377
+ """
378
+ return self.rank == 0
379
+
380
+ def basis(self):
381
+ """
382
+ Return a set of basis elements.
383
+
384
+ Examples
385
+ ========
386
+
387
+ >>> from sympy.abc import x
388
+ >>> from sympy import QQ
389
+ >>> QQ.old_poly_ring(x).free_module(3).basis()
390
+ ([1, 0, 0], [0, 1, 0], [0, 0, 1])
391
+ """
392
+ from sympy.matrices import eye
393
+ M = eye(self.rank)
394
+ return tuple(self.convert(M.row(i)) for i in range(self.rank))
395
+
396
+ def quotient_module(self, submodule):
397
+ """
398
+ Return a quotient module.
399
+
400
+ Examples
401
+ ========
402
+
403
+ >>> from sympy.abc import x
404
+ >>> from sympy import QQ
405
+ >>> M = QQ.old_poly_ring(x).free_module(2)
406
+ >>> M.quotient_module(M.submodule([1, x], [x, 2]))
407
+ QQ[x]**2/<[1, x], [x, 2]>
408
+
409
+ Or more conicisely, using the overloaded division operator:
410
+
411
+ >>> QQ.old_poly_ring(x).free_module(2) / [[1, x], [x, 2]]
412
+ QQ[x]**2/<[1, x], [x, 2]>
413
+ """
414
+ return QuotientModule(self.ring, self, submodule)
415
+
416
+ def multiply_ideal(self, other):
417
+ """
418
+ Multiply ``self`` by the ideal ``other``.
419
+
420
+ Examples
421
+ ========
422
+
423
+ >>> from sympy.abc import x
424
+ >>> from sympy import QQ
425
+ >>> I = QQ.old_poly_ring(x).ideal(x)
426
+ >>> F = QQ.old_poly_ring(x).free_module(2)
427
+ >>> F.multiply_ideal(I)
428
+ <[x, 0], [0, x]>
429
+ """
430
+ return self.submodule(*self.basis()).multiply_ideal(other)
431
+
432
+ def identity_hom(self):
433
+ """
434
+ Return the identity homomorphism on ``self``.
435
+
436
+ Examples
437
+ ========
438
+
439
+ >>> from sympy.abc import x
440
+ >>> from sympy import QQ
441
+ >>> QQ.old_poly_ring(x).free_module(2).identity_hom()
442
+ Matrix([
443
+ [1, 0], : QQ[x]**2 -> QQ[x]**2
444
+ [0, 1]])
445
+ """
446
+ from sympy.polys.agca.homomorphisms import homomorphism
447
+ return homomorphism(self, self, self.basis())
448
+
449
+
450
+ class FreeModulePolyRing(FreeModule):
451
+ """
452
+ Free module over a generalized polynomial ring.
453
+
454
+ Do not instantiate this, use the constructor method of the ring instead:
455
+
456
+ Examples
457
+ ========
458
+
459
+ >>> from sympy.abc import x
460
+ >>> from sympy import QQ
461
+ >>> F = QQ.old_poly_ring(x).free_module(3)
462
+ >>> F
463
+ QQ[x]**3
464
+ >>> F.contains([x, 1, 0])
465
+ True
466
+ >>> F.contains([1/x, 0, 1])
467
+ False
468
+ """
469
+
470
+ def __init__(self, ring, rank):
471
+ from sympy.polys.domains.old_polynomialring import PolynomialRingBase
472
+ FreeModule.__init__(self, ring, rank)
473
+ if not isinstance(ring, PolynomialRingBase):
474
+ raise NotImplementedError('This implementation only works over '
475
+ + 'polynomial rings, got %s' % ring)
476
+ if not isinstance(ring.dom, Field):
477
+ raise NotImplementedError('Ground domain must be a field, '
478
+ + 'got %s' % ring.dom)
479
+
480
+ def submodule(self, *gens, **opts):
481
+ """
482
+ Generate a submodule.
483
+
484
+ Examples
485
+ ========
486
+
487
+ >>> from sympy.abc import x, y
488
+ >>> from sympy import QQ
489
+ >>> M = QQ.old_poly_ring(x, y).free_module(2).submodule([x, x + y])
490
+ >>> M
491
+ <[x, x + y]>
492
+ >>> M.contains([2*x, 2*x + 2*y])
493
+ True
494
+ >>> M.contains([x, y])
495
+ False
496
+ """
497
+ return SubModulePolyRing(gens, self, **opts)
498
+
499
+
500
+ class FreeModuleQuotientRing(FreeModule):
501
+ """
502
+ Free module over a quotient ring.
503
+
504
+ Do not instantiate this, use the constructor method of the ring instead:
505
+
506
+ Examples
507
+ ========
508
+
509
+ >>> from sympy.abc import x
510
+ >>> from sympy import QQ
511
+ >>> F = (QQ.old_poly_ring(x)/[x**2 + 1]).free_module(3)
512
+ >>> F
513
+ (QQ[x]/<x**2 + 1>)**3
514
+
515
+ Attributes
516
+
517
+ - quot - the quotient module `R^n / IR^n`, where `R/I` is our ring
518
+ """
519
+
520
+ def __init__(self, ring, rank):
521
+ from sympy.polys.domains.quotientring import QuotientRing
522
+ FreeModule.__init__(self, ring, rank)
523
+ if not isinstance(ring, QuotientRing):
524
+ raise NotImplementedError('This implementation only works over '
525
+ + 'quotient rings, got %s' % ring)
526
+ F = self.ring.ring.free_module(self.rank)
527
+ self.quot = F / (self.ring.base_ideal*F)
528
+
529
+ def __repr__(self):
530
+ return "(" + repr(self.ring) + ")" + "**" + repr(self.rank)
531
+
532
+ def submodule(self, *gens, **opts):
533
+ """
534
+ Generate a submodule.
535
+
536
+ Examples
537
+ ========
538
+
539
+ >>> from sympy.abc import x, y
540
+ >>> from sympy import QQ
541
+ >>> M = (QQ.old_poly_ring(x, y)/[x**2 - y**2]).free_module(2).submodule([x, x + y])
542
+ >>> M
543
+ <[x + <x**2 - y**2>, x + y + <x**2 - y**2>]>
544
+ >>> M.contains([y**2, x**2 + x*y])
545
+ True
546
+ >>> M.contains([x, y])
547
+ False
548
+ """
549
+ return SubModuleQuotientRing(gens, self, **opts)
550
+
551
+ def lift(self, elem):
552
+ """
553
+ Lift the element ``elem`` of self to the module self.quot.
554
+
555
+ Note that self.quot is the same set as self, just as an R-module
556
+ and not as an R/I-module, so this makes sense.
557
+
558
+ Examples
559
+ ========
560
+
561
+ >>> from sympy.abc import x
562
+ >>> from sympy import QQ
563
+ >>> F = (QQ.old_poly_ring(x)/[x**2 + 1]).free_module(2)
564
+ >>> e = F.convert([1, 0])
565
+ >>> e
566
+ [1 + <x**2 + 1>, 0 + <x**2 + 1>]
567
+ >>> L = F.quot
568
+ >>> l = F.lift(e)
569
+ >>> l
570
+ [1, 0] + <[x**2 + 1, 0], [0, x**2 + 1]>
571
+ >>> L.contains(l)
572
+ True
573
+ """
574
+ return self.quot.convert([x.data for x in elem])
575
+
576
+ def unlift(self, elem):
577
+ """
578
+ Push down an element of self.quot to self.
579
+
580
+ This undoes ``lift``.
581
+
582
+ Examples
583
+ ========
584
+
585
+ >>> from sympy.abc import x
586
+ >>> from sympy import QQ
587
+ >>> F = (QQ.old_poly_ring(x)/[x**2 + 1]).free_module(2)
588
+ >>> e = F.convert([1, 0])
589
+ >>> l = F.lift(e)
590
+ >>> e == l
591
+ False
592
+ >>> e == F.unlift(l)
593
+ True
594
+ """
595
+ return self.convert(elem.data)
596
+
597
+ ##########################################################################
598
+ ## Submodules and subquotients ###########################################
599
+ ##########################################################################
600
+
601
+
602
+ class SubModule(Module):
603
+ """
604
+ Base class for submodules.
605
+
606
+ Attributes:
607
+
608
+ - container - containing module
609
+ - gens - generators (subset of containing module)
610
+ - rank - rank of containing module
611
+
612
+ Non-implemented methods:
613
+
614
+ - _contains
615
+ - _syzygies
616
+ - _in_terms_of_generators
617
+ - _intersect
618
+ - _module_quotient
619
+
620
+ Methods that likely need change in subclasses:
621
+
622
+ - reduce_element
623
+ """
624
+
625
+ def __init__(self, gens, container):
626
+ Module.__init__(self, container.ring)
627
+ self.gens = tuple(container.convert(x) for x in gens)
628
+ self.container = container
629
+ self.rank = container.rank
630
+ self.ring = container.ring
631
+ self.dtype = container.dtype
632
+
633
+ def __repr__(self):
634
+ return "<" + ", ".join(repr(x) for x in self.gens) + ">"
635
+
636
+ def _contains(self, other):
637
+ """Implementation of containment.
638
+ Other is guaranteed to be FreeModuleElement."""
639
+ raise NotImplementedError
640
+
641
+ def _syzygies(self):
642
+ """Implementation of syzygy computation wrt self generators."""
643
+ raise NotImplementedError
644
+
645
+ def _in_terms_of_generators(self, e):
646
+ """Implementation of expression in terms of generators."""
647
+ raise NotImplementedError
648
+
649
+ def convert(self, elem, M=None):
650
+ """
651
+ Convert ``elem`` into the internal represantition.
652
+
653
+ Mostly called implicitly.
654
+
655
+ Examples
656
+ ========
657
+
658
+ >>> from sympy.abc import x
659
+ >>> from sympy import QQ
660
+ >>> M = QQ.old_poly_ring(x).free_module(2).submodule([1, x])
661
+ >>> M.convert([2, 2*x])
662
+ [2, 2*x]
663
+ """
664
+ if isinstance(elem, self.container.dtype) and elem.module is self:
665
+ return elem
666
+ r = copy(self.container.convert(elem, M))
667
+ r.module = self
668
+ if not self._contains(r):
669
+ raise CoercionFailed
670
+ return r
671
+
672
+ def _intersect(self, other):
673
+ """Implementation of intersection.
674
+ Other is guaranteed to be a submodule of same free module."""
675
+ raise NotImplementedError
676
+
677
+ def _module_quotient(self, other):
678
+ """Implementation of quotient.
679
+ Other is guaranteed to be a submodule of same free module."""
680
+ raise NotImplementedError
681
+
682
+ def intersect(self, other, **options):
683
+ """
684
+ Returns the intersection of ``self`` with submodule ``other``.
685
+
686
+ Examples
687
+ ========
688
+
689
+ >>> from sympy.abc import x, y
690
+ >>> from sympy import QQ
691
+ >>> F = QQ.old_poly_ring(x, y).free_module(2)
692
+ >>> F.submodule([x, x]).intersect(F.submodule([y, y]))
693
+ <[x*y, x*y]>
694
+
695
+ Some implementation allow further options to be passed. Currently, to
696
+ only one implemented is ``relations=True``, in which case the function
697
+ will return a triple ``(res, rela, relb)``, where ``res`` is the
698
+ intersection module, and ``rela`` and ``relb`` are lists of coefficient
699
+ vectors, expressing the generators of ``res`` in terms of the
700
+ generators of ``self`` (``rela``) and ``other`` (``relb``).
701
+
702
+ >>> F.submodule([x, x]).intersect(F.submodule([y, y]), relations=True)
703
+ (<[x*y, x*y]>, [(y,)], [(x,)])
704
+
705
+ The above result says: the intersection module is generated by the
706
+ single element `(-xy, -xy) = -y (x, x) = -x (y, y)`, where
707
+ `(x, x)` and `(y, y)` respectively are the unique generators of
708
+ the two modules being intersected.
709
+ """
710
+ if not isinstance(other, SubModule):
711
+ raise TypeError('%s is not a SubModule' % other)
712
+ if other.container != self.container:
713
+ raise ValueError(
714
+ '%s is contained in a different free module' % other)
715
+ return self._intersect(other, **options)
716
+
717
+ def module_quotient(self, other, **options):
718
+ r"""
719
+ Returns the module quotient of ``self`` by submodule ``other``.
720
+
721
+ That is, if ``self`` is the module `M` and ``other`` is `N`, then
722
+ return the ideal `\{f \in R | fN \subset M\}`.
723
+
724
+ Examples
725
+ ========
726
+
727
+ >>> from sympy import QQ
728
+ >>> from sympy.abc import x, y
729
+ >>> F = QQ.old_poly_ring(x, y).free_module(2)
730
+ >>> S = F.submodule([x*y, x*y])
731
+ >>> T = F.submodule([x, x])
732
+ >>> S.module_quotient(T)
733
+ <y>
734
+
735
+ Some implementations allow further options to be passed. Currently, the
736
+ only one implemented is ``relations=True``, which may only be passed
737
+ if ``other`` is principal. In this case the function
738
+ will return a pair ``(res, rel)`` where ``res`` is the ideal, and
739
+ ``rel`` is a list of coefficient vectors, expressing the generators of
740
+ the ideal, multiplied by the generator of ``other`` in terms of
741
+ generators of ``self``.
742
+
743
+ >>> S.module_quotient(T, relations=True)
744
+ (<y>, [[1]])
745
+
746
+ This means that the quotient ideal is generated by the single element
747
+ `y`, and that `y (x, x) = 1 (xy, xy)`, `(x, x)` and `(xy, xy)` being
748
+ the generators of `T` and `S`, respectively.
749
+ """
750
+ if not isinstance(other, SubModule):
751
+ raise TypeError('%s is not a SubModule' % other)
752
+ if other.container != self.container:
753
+ raise ValueError(
754
+ '%s is contained in a different free module' % other)
755
+ return self._module_quotient(other, **options)
756
+
757
+ def union(self, other):
758
+ """
759
+ Returns the module generated by the union of ``self`` and ``other``.
760
+
761
+ Examples
762
+ ========
763
+
764
+ >>> from sympy.abc import x
765
+ >>> from sympy import QQ
766
+ >>> F = QQ.old_poly_ring(x).free_module(1)
767
+ >>> M = F.submodule([x**2 + x]) # <x(x+1)>
768
+ >>> N = F.submodule([x**2 - 1]) # <(x-1)(x+1)>
769
+ >>> M.union(N) == F.submodule([x+1])
770
+ True
771
+ """
772
+ if not isinstance(other, SubModule):
773
+ raise TypeError('%s is not a SubModule' % other)
774
+ if other.container != self.container:
775
+ raise ValueError(
776
+ '%s is contained in a different free module' % other)
777
+ return self.__class__(self.gens + other.gens, self.container)
778
+
779
+ def is_zero(self):
780
+ """
781
+ Return True if ``self`` is a zero module.
782
+
783
+ Examples
784
+ ========
785
+
786
+ >>> from sympy.abc import x
787
+ >>> from sympy import QQ
788
+ >>> F = QQ.old_poly_ring(x).free_module(2)
789
+ >>> F.submodule([x, 1]).is_zero()
790
+ False
791
+ >>> F.submodule([0, 0]).is_zero()
792
+ True
793
+ """
794
+ return all(x == 0 for x in self.gens)
795
+
796
+ def submodule(self, *gens):
797
+ """
798
+ Generate a submodule.
799
+
800
+ Examples
801
+ ========
802
+
803
+ >>> from sympy.abc import x
804
+ >>> from sympy import QQ
805
+ >>> M = QQ.old_poly_ring(x).free_module(2).submodule([x, 1])
806
+ >>> M.submodule([x**2, x])
807
+ <[x**2, x]>
808
+ """
809
+ if not self.subset(gens):
810
+ raise ValueError('%s not a subset of %s' % (gens, self))
811
+ return self.__class__(gens, self.container)
812
+
813
+ def is_full_module(self):
814
+ """
815
+ Return True if ``self`` is the entire free module.
816
+
817
+ Examples
818
+ ========
819
+
820
+ >>> from sympy.abc import x
821
+ >>> from sympy import QQ
822
+ >>> F = QQ.old_poly_ring(x).free_module(2)
823
+ >>> F.submodule([x, 1]).is_full_module()
824
+ False
825
+ >>> F.submodule([1, 1], [1, 2]).is_full_module()
826
+ True
827
+ """
828
+ return all(self.contains(x) for x in self.container.basis())
829
+
830
+ def is_submodule(self, other):
831
+ """
832
+ Returns True if ``other`` is a submodule of ``self``.
833
+
834
+ >>> from sympy.abc import x
835
+ >>> from sympy import QQ
836
+ >>> F = QQ.old_poly_ring(x).free_module(2)
837
+ >>> M = F.submodule([2, x])
838
+ >>> N = M.submodule([2*x, x**2])
839
+ >>> M.is_submodule(M)
840
+ True
841
+ >>> M.is_submodule(N)
842
+ True
843
+ >>> N.is_submodule(M)
844
+ False
845
+ """
846
+ if isinstance(other, SubModule):
847
+ return self.container == other.container and \
848
+ all(self.contains(x) for x in other.gens)
849
+ if isinstance(other, (FreeModule, QuotientModule)):
850
+ return self.container == other and self.is_full_module()
851
+ return False
852
+
853
+ def syzygy_module(self, **opts):
854
+ r"""
855
+ Compute the syzygy module of the generators of ``self``.
856
+
857
+ Suppose `M` is generated by `f_1, \ldots, f_n` over the ring
858
+ `R`. Consider the homomorphism `\phi: R^n \to M`, given by
859
+ sending `(r_1, \ldots, r_n) \to r_1 f_1 + \cdots + r_n f_n`.
860
+ The syzygy module is defined to be the kernel of `\phi`.
861
+
862
+ Examples
863
+ ========
864
+
865
+ The syzygy module is zero iff the generators generate freely a free
866
+ submodule:
867
+
868
+ >>> from sympy.abc import x, y
869
+ >>> from sympy import QQ
870
+ >>> QQ.old_poly_ring(x).free_module(2).submodule([1, 0], [1, 1]).syzygy_module().is_zero()
871
+ True
872
+
873
+ A slightly more interesting example:
874
+
875
+ >>> M = QQ.old_poly_ring(x, y).free_module(2).submodule([x, 2*x], [y, 2*y])
876
+ >>> S = QQ.old_poly_ring(x, y).free_module(2).submodule([y, -x])
877
+ >>> M.syzygy_module() == S
878
+ True
879
+ """
880
+ F = self.ring.free_module(len(self.gens))
881
+ # NOTE we filter out zero syzygies. This is for convenience of the
882
+ # _syzygies function and not meant to replace any real "generating set
883
+ # reduction" algorithm
884
+ return F.submodule(*[x for x in self._syzygies() if F.convert(x) != 0],
885
+ **opts)
886
+
887
+ def in_terms_of_generators(self, e):
888
+ """
889
+ Express element ``e`` of ``self`` in terms of the generators.
890
+
891
+ Examples
892
+ ========
893
+
894
+ >>> from sympy.abc import x
895
+ >>> from sympy import QQ
896
+ >>> F = QQ.old_poly_ring(x).free_module(2)
897
+ >>> M = F.submodule([1, 0], [1, 1])
898
+ >>> M.in_terms_of_generators([x, x**2])
899
+ [-x**2 + x, x**2]
900
+ """
901
+ try:
902
+ e = self.convert(e)
903
+ except CoercionFailed:
904
+ raise ValueError('%s is not an element of %s' % (e, self))
905
+ return self._in_terms_of_generators(e)
906
+
907
+ def reduce_element(self, x):
908
+ """
909
+ Reduce the element ``x`` of our ring modulo the ideal ``self``.
910
+
911
+ Here "reduce" has no specific meaning, it could return a unique normal
912
+ form, simplify the expression a bit, or just do nothing.
913
+ """
914
+ return x
915
+
916
+ def quotient_module(self, other, **opts):
917
+ """
918
+ Return a quotient module.
919
+
920
+ This is the same as taking a submodule of a quotient of the containing
921
+ module.
922
+
923
+ Examples
924
+ ========
925
+
926
+ >>> from sympy.abc import x
927
+ >>> from sympy import QQ
928
+ >>> F = QQ.old_poly_ring(x).free_module(2)
929
+ >>> S1 = F.submodule([x, 1])
930
+ >>> S2 = F.submodule([x**2, x])
931
+ >>> S1.quotient_module(S2)
932
+ <[x, 1] + <[x**2, x]>>
933
+
934
+ Or more coincisely, using the overloaded division operator:
935
+
936
+ >>> F.submodule([x, 1]) / [(x**2, x)]
937
+ <[x, 1] + <[x**2, x]>>
938
+ """
939
+ if not self.is_submodule(other):
940
+ raise ValueError('%s not a submodule of %s' % (other, self))
941
+ return SubQuotientModule(self.gens,
942
+ self.container.quotient_module(other), **opts)
943
+
944
+ def __add__(self, oth):
945
+ return self.container.quotient_module(self).convert(oth)
946
+
947
+ __radd__ = __add__
948
+
949
+ def multiply_ideal(self, I):
950
+ """
951
+ Multiply ``self`` by the ideal ``I``.
952
+
953
+ Examples
954
+ ========
955
+
956
+ >>> from sympy.abc import x
957
+ >>> from sympy import QQ
958
+ >>> I = QQ.old_poly_ring(x).ideal(x**2)
959
+ >>> M = QQ.old_poly_ring(x).free_module(2).submodule([1, 1])
960
+ >>> I*M
961
+ <[x**2, x**2]>
962
+ """
963
+ return self.submodule(*[x*g for [x] in I._module.gens for g in self.gens])
964
+
965
+ def inclusion_hom(self):
966
+ """
967
+ Return a homomorphism representing the inclusion map of ``self``.
968
+
969
+ That is, the natural map from ``self`` to ``self.container``.
970
+
971
+ Examples
972
+ ========
973
+
974
+ >>> from sympy.abc import x
975
+ >>> from sympy import QQ
976
+ >>> QQ.old_poly_ring(x).free_module(2).submodule([x, x]).inclusion_hom()
977
+ Matrix([
978
+ [1, 0], : <[x, x]> -> QQ[x]**2
979
+ [0, 1]])
980
+ """
981
+ return self.container.identity_hom().restrict_domain(self)
982
+
983
+ def identity_hom(self):
984
+ """
985
+ Return the identity homomorphism on ``self``.
986
+
987
+ Examples
988
+ ========
989
+
990
+ >>> from sympy.abc import x
991
+ >>> from sympy import QQ
992
+ >>> QQ.old_poly_ring(x).free_module(2).submodule([x, x]).identity_hom()
993
+ Matrix([
994
+ [1, 0], : <[x, x]> -> <[x, x]>
995
+ [0, 1]])
996
+ """
997
+ return self.container.identity_hom().restrict_domain(
998
+ self).restrict_codomain(self)
999
+
1000
+
1001
+ class SubQuotientModule(SubModule):
1002
+ """
1003
+ Submodule of a quotient module.
1004
+
1005
+ Equivalently, quotient module of a submodule.
1006
+
1007
+ Do not instantiate this, instead use the submodule or quotient_module
1008
+ constructing methods:
1009
+
1010
+ >>> from sympy.abc import x
1011
+ >>> from sympy import QQ
1012
+ >>> F = QQ.old_poly_ring(x).free_module(2)
1013
+ >>> S = F.submodule([1, 0], [1, x])
1014
+ >>> Q = F/[(1, 0)]
1015
+ >>> S/[(1, 0)] == Q.submodule([5, x])
1016
+ True
1017
+
1018
+ Attributes:
1019
+
1020
+ - base - base module we are quotient of
1021
+ - killed_module - submodule used to form the quotient
1022
+ """
1023
+ def __init__(self, gens, container, **opts):
1024
+ SubModule.__init__(self, gens, container)
1025
+ self.killed_module = self.container.killed_module
1026
+ # XXX it is important for some code below that the generators of base
1027
+ # are in this particular order!
1028
+ self.base = self.container.base.submodule(
1029
+ *[x.data for x in self.gens], **opts).union(self.killed_module)
1030
+
1031
+ def _contains(self, elem):
1032
+ return self.base.contains(elem.data)
1033
+
1034
+ def _syzygies(self):
1035
+ # let N = self.killed_module be generated by e_1, ..., e_r
1036
+ # let F = self.base be generated by f_1, ..., f_s and e_1, ..., e_r
1037
+ # Then self = F/N.
1038
+ # Let phi: R**s --> self be the evident surjection.
1039
+ # Similarly psi: R**(s + r) --> F.
1040
+ # We need to find generators for ker(phi). Let chi: R**s --> F be the
1041
+ # evident lift of phi. For X in R**s, phi(X) = 0 iff chi(X) is
1042
+ # contained in N, iff there exists Y in R**r such that
1043
+ # psi(X, Y) = 0.
1044
+ # Hence if alpha: R**(s + r) --> R**s is the projection map, then
1045
+ # ker(phi) = alpha ker(psi).
1046
+ return [X[:len(self.gens)] for X in self.base._syzygies()]
1047
+
1048
+ def _in_terms_of_generators(self, e):
1049
+ return self.base._in_terms_of_generators(e.data)[:len(self.gens)]
1050
+
1051
+ def is_full_module(self):
1052
+ """
1053
+ Return True if ``self`` is the entire free module.
1054
+
1055
+ Examples
1056
+ ========
1057
+
1058
+ >>> from sympy.abc import x
1059
+ >>> from sympy import QQ
1060
+ >>> F = QQ.old_poly_ring(x).free_module(2)
1061
+ >>> F.submodule([x, 1]).is_full_module()
1062
+ False
1063
+ >>> F.submodule([1, 1], [1, 2]).is_full_module()
1064
+ True
1065
+ """
1066
+ return self.base.is_full_module()
1067
+
1068
+ def quotient_hom(self):
1069
+ """
1070
+ Return the quotient homomorphism to self.
1071
+
1072
+ That is, return the natural map from ``self.base`` to ``self``.
1073
+
1074
+ Examples
1075
+ ========
1076
+
1077
+ >>> from sympy.abc import x
1078
+ >>> from sympy import QQ
1079
+ >>> M = (QQ.old_poly_ring(x).free_module(2) / [(1, x)]).submodule([1, 0])
1080
+ >>> M.quotient_hom()
1081
+ Matrix([
1082
+ [1, 0], : <[1, 0], [1, x]> -> <[1, 0] + <[1, x]>, [1, x] + <[1, x]>>
1083
+ [0, 1]])
1084
+ """
1085
+ return self.base.identity_hom().quotient_codomain(self.killed_module)
1086
+
1087
+
1088
+ _subs0 = lambda x: x[0]
1089
+ _subs1 = lambda x: x[1:]
1090
+
1091
+
1092
+ class ModuleOrder(ProductOrder):
1093
+ """A product monomial order with a zeroth term as module index."""
1094
+
1095
+ def __init__(self, o1, o2, TOP):
1096
+ if TOP:
1097
+ ProductOrder.__init__(self, (o2, _subs1), (o1, _subs0))
1098
+ else:
1099
+ ProductOrder.__init__(self, (o1, _subs0), (o2, _subs1))
1100
+
1101
+
1102
+ class SubModulePolyRing(SubModule):
1103
+ """
1104
+ Submodule of a free module over a generalized polynomial ring.
1105
+
1106
+ Do not instantiate this, use the constructor method of FreeModule instead:
1107
+
1108
+ >>> from sympy.abc import x, y
1109
+ >>> from sympy import QQ
1110
+ >>> F = QQ.old_poly_ring(x, y).free_module(2)
1111
+ >>> F.submodule([x, y], [1, 0])
1112
+ <[x, y], [1, 0]>
1113
+
1114
+ Attributes:
1115
+
1116
+ - order - monomial order used
1117
+ """
1118
+
1119
+ #self._gb - cached groebner basis
1120
+ #self._gbe - cached groebner basis relations
1121
+
1122
+ def __init__(self, gens, container, order="lex", TOP=True):
1123
+ SubModule.__init__(self, gens, container)
1124
+ if not isinstance(container, FreeModulePolyRing):
1125
+ raise NotImplementedError('This implementation is for submodules of '
1126
+ + 'FreeModulePolyRing, got %s' % container)
1127
+ self.order = ModuleOrder(monomial_key(order), self.ring.order, TOP)
1128
+ self._gb = None
1129
+ self._gbe = None
1130
+
1131
+ def __eq__(self, other):
1132
+ if isinstance(other, SubModulePolyRing) and self.order != other.order:
1133
+ return False
1134
+ return SubModule.__eq__(self, other)
1135
+
1136
+ def _groebner(self, extended=False):
1137
+ """Returns a standard basis in sdm form."""
1138
+ from sympy.polys.distributedmodules import sdm_groebner, sdm_nf_mora
1139
+ if self._gbe is None and extended:
1140
+ gb, gbe = sdm_groebner(
1141
+ [self.ring._vector_to_sdm(x, self.order) for x in self.gens],
1142
+ sdm_nf_mora, self.order, self.ring.dom, extended=True)
1143
+ self._gb, self._gbe = tuple(gb), tuple(gbe)
1144
+ if self._gb is None:
1145
+ self._gb = tuple(sdm_groebner(
1146
+ [self.ring._vector_to_sdm(x, self.order) for x in self.gens],
1147
+ sdm_nf_mora, self.order, self.ring.dom))
1148
+ if extended:
1149
+ return self._gb, self._gbe
1150
+ else:
1151
+ return self._gb
1152
+
1153
+ def _groebner_vec(self, extended=False):
1154
+ """Returns a standard basis in element form."""
1155
+ if not extended:
1156
+ return [FreeModuleElement(self,
1157
+ tuple(self.ring._sdm_to_vector(x, self.rank)))
1158
+ for x in self._groebner()]
1159
+ gb, gbe = self._groebner(extended=True)
1160
+ return ([self.convert(self.ring._sdm_to_vector(x, self.rank))
1161
+ for x in gb],
1162
+ [self.ring._sdm_to_vector(x, len(self.gens)) for x in gbe])
1163
+
1164
+ def _contains(self, x):
1165
+ from sympy.polys.distributedmodules import sdm_zero, sdm_nf_mora
1166
+ return sdm_nf_mora(self.ring._vector_to_sdm(x, self.order),
1167
+ self._groebner(), self.order, self.ring.dom) == \
1168
+ sdm_zero()
1169
+
1170
+ def _syzygies(self):
1171
+ """Compute syzygies. See [SCA, algorithm 2.5.4]."""
1172
+ # NOTE if self.gens is a standard basis, this can be done more
1173
+ # efficiently using Schreyer's theorem
1174
+
1175
+ # First bullet point
1176
+ k = len(self.gens)
1177
+ r = self.rank
1178
+ zero = self.ring.convert(0)
1179
+ one = self.ring.convert(1)
1180
+ Rkr = self.ring.free_module(r + k)
1181
+ newgens = []
1182
+ for j, f in enumerate(self.gens):
1183
+ m = [0]*(r + k)
1184
+ for i, v in enumerate(f):
1185
+ m[i] = f[i]
1186
+ for i in range(k):
1187
+ m[r + i] = one if j == i else zero
1188
+ m = FreeModuleElement(Rkr, tuple(m))
1189
+ newgens.append(m)
1190
+ # Note: we need *descending* order on module index, and TOP=False to
1191
+ # get an elimination order
1192
+ F = Rkr.submodule(*newgens, order='ilex', TOP=False)
1193
+
1194
+ # Second bullet point: standard basis of F
1195
+ G = F._groebner_vec()
1196
+
1197
+ # Third bullet point: G0 = G intersect the new k components
1198
+ G0 = [x[r:] for x in G if all(y == zero for y in x[:r])]
1199
+
1200
+ # Fourth and fifth bullet points: we are done
1201
+ return G0
1202
+
1203
+ def _in_terms_of_generators(self, e):
1204
+ """Expression in terms of generators. See [SCA, 2.8.1]."""
1205
+ # NOTE: if gens is a standard basis, this can be done more efficiently
1206
+ M = self.ring.free_module(self.rank).submodule(*((e,) + self.gens))
1207
+ S = M.syzygy_module(
1208
+ order="ilex", TOP=False) # We want decreasing order!
1209
+ G = S._groebner_vec()
1210
+ # This list cannot not be empty since e is an element
1211
+ e = [x for x in G if self.ring.is_unit(x[0])][0]
1212
+ return [-x/e[0] for x in e[1:]]
1213
+
1214
+ def reduce_element(self, x, NF=None):
1215
+ """
1216
+ Reduce the element ``x`` of our container modulo ``self``.
1217
+
1218
+ This applies the normal form ``NF`` to ``x``. If ``NF`` is passed
1219
+ as none, the default Mora normal form is used (which is not unique!).
1220
+ """
1221
+ from sympy.polys.distributedmodules import sdm_nf_mora
1222
+ if NF is None:
1223
+ NF = sdm_nf_mora
1224
+ return self.container.convert(self.ring._sdm_to_vector(NF(
1225
+ self.ring._vector_to_sdm(x, self.order), self._groebner(),
1226
+ self.order, self.ring.dom),
1227
+ self.rank))
1228
+
1229
+ def _intersect(self, other, relations=False):
1230
+ # See: [SCA, section 2.8.2]
1231
+ fi = self.gens
1232
+ hi = other.gens
1233
+ r = self.rank
1234
+ ci = [[0]*(2*r) for _ in range(r)]
1235
+ for k in range(r):
1236
+ ci[k][k] = 1
1237
+ ci[k][r + k] = 1
1238
+ di = [list(f) + [0]*r for f in fi]
1239
+ ei = [[0]*r + list(h) for h in hi]
1240
+ syz = self.ring.free_module(2*r).submodule(*(ci + di + ei))._syzygies()
1241
+ nonzero = [x for x in syz if any(y != self.ring.zero for y in x[:r])]
1242
+ res = self.container.submodule(*([-y for y in x[:r]] for x in nonzero))
1243
+ reln1 = [x[r:r + len(fi)] for x in nonzero]
1244
+ reln2 = [x[r + len(fi):] for x in nonzero]
1245
+ if relations:
1246
+ return res, reln1, reln2
1247
+ return res
1248
+
1249
+ def _module_quotient(self, other, relations=False):
1250
+ # See: [SCA, section 2.8.4]
1251
+ if relations and len(other.gens) != 1:
1252
+ raise NotImplementedError
1253
+ if len(other.gens) == 0:
1254
+ return self.ring.ideal(1)
1255
+ elif len(other.gens) == 1:
1256
+ # We do some trickery. Let f be the (vector!) generating ``other``
1257
+ # and f1, .., fn be the (vectors) generating self.
1258
+ # Consider the submodule of R^{r+1} generated by (f, 1) and
1259
+ # {(fi, 0) | i}. Then the intersection with the last module
1260
+ # component yields the quotient.
1261
+ g1 = list(other.gens[0]) + [1]
1262
+ gi = [list(x) + [0] for x in self.gens]
1263
+ # NOTE: We *need* to use an elimination order
1264
+ M = self.ring.free_module(self.rank + 1).submodule(*([g1] + gi),
1265
+ order='ilex', TOP=False)
1266
+ if not relations:
1267
+ return self.ring.ideal(*[x[-1] for x in M._groebner_vec() if
1268
+ all(y == self.ring.zero for y in x[:-1])])
1269
+ else:
1270
+ G, R = M._groebner_vec(extended=True)
1271
+ indices = [i for i, x in enumerate(G) if
1272
+ all(y == self.ring.zero for y in x[:-1])]
1273
+ return (self.ring.ideal(*[G[i][-1] for i in indices]),
1274
+ [[-x for x in R[i][1:]] for i in indices])
1275
+ # For more generators, we use I : <h1, .., hn> = intersection of
1276
+ # {I : <hi> | i}
1277
+ # TODO this can be done more efficiently
1278
+ return reduce(lambda x, y: x.intersect(y),
1279
+ (self._module_quotient(self.container.submodule(x)) for x in other.gens))
1280
+
1281
+
1282
+ class SubModuleQuotientRing(SubModule):
1283
+ """
1284
+ Class for submodules of free modules over quotient rings.
1285
+
1286
+ Do not instantiate this. Instead use the submodule methods.
1287
+
1288
+ >>> from sympy.abc import x, y
1289
+ >>> from sympy import QQ
1290
+ >>> M = (QQ.old_poly_ring(x, y)/[x**2 - y**2]).free_module(2).submodule([x, x + y])
1291
+ >>> M
1292
+ <[x + <x**2 - y**2>, x + y + <x**2 - y**2>]>
1293
+ >>> M.contains([y**2, x**2 + x*y])
1294
+ True
1295
+ >>> M.contains([x, y])
1296
+ False
1297
+
1298
+ Attributes:
1299
+
1300
+ - quot - the subquotient of `R^n/IR^n` generated by lifts of our generators
1301
+ """
1302
+
1303
+ def __init__(self, gens, container):
1304
+ SubModule.__init__(self, gens, container)
1305
+ self.quot = self.container.quot.submodule(
1306
+ *[self.container.lift(x) for x in self.gens])
1307
+
1308
+ def _contains(self, elem):
1309
+ return self.quot._contains(self.container.lift(elem))
1310
+
1311
+ def _syzygies(self):
1312
+ return [tuple(self.ring.convert(y, self.quot.ring) for y in x)
1313
+ for x in self.quot._syzygies()]
1314
+
1315
+ def _in_terms_of_generators(self, elem):
1316
+ return [self.ring.convert(x, self.quot.ring) for x in
1317
+ self.quot._in_terms_of_generators(self.container.lift(elem))]
1318
+
1319
+ ##########################################################################
1320
+ ## Quotient Modules ######################################################
1321
+ ##########################################################################
1322
+
1323
+
1324
+ class QuotientModuleElement(ModuleElement):
1325
+ """Element of a quotient module."""
1326
+
1327
+ def eq(self, d1, d2):
1328
+ """Equality comparison."""
1329
+ return self.module.killed_module.contains(d1 - d2)
1330
+
1331
+ def __repr__(self):
1332
+ return repr(self.data) + " + " + repr(self.module.killed_module)
1333
+
1334
+
1335
+ class QuotientModule(Module):
1336
+ """
1337
+ Class for quotient modules.
1338
+
1339
+ Do not instantiate this directly. For subquotients, see the
1340
+ SubQuotientModule class.
1341
+
1342
+ Attributes:
1343
+
1344
+ - base - the base module we are a quotient of
1345
+ - killed_module - the submodule used to form the quotient
1346
+ - rank of the base
1347
+ """
1348
+
1349
+ dtype = QuotientModuleElement
1350
+
1351
+ def __init__(self, ring, base, submodule):
1352
+ Module.__init__(self, ring)
1353
+ if not base.is_submodule(submodule):
1354
+ raise ValueError('%s is not a submodule of %s' % (submodule, base))
1355
+ self.base = base
1356
+ self.killed_module = submodule
1357
+ self.rank = base.rank
1358
+
1359
+ def __repr__(self):
1360
+ return repr(self.base) + "/" + repr(self.killed_module)
1361
+
1362
+ def is_zero(self):
1363
+ """
1364
+ Return True if ``self`` is a zero module.
1365
+
1366
+ This happens if and only if the base module is the same as the
1367
+ submodule being killed.
1368
+
1369
+ Examples
1370
+ ========
1371
+
1372
+ >>> from sympy.abc import x
1373
+ >>> from sympy import QQ
1374
+ >>> F = QQ.old_poly_ring(x).free_module(2)
1375
+ >>> (F/[(1, 0)]).is_zero()
1376
+ False
1377
+ >>> (F/[(1, 0), (0, 1)]).is_zero()
1378
+ True
1379
+ """
1380
+ return self.base == self.killed_module
1381
+
1382
+ def is_submodule(self, other):
1383
+ """
1384
+ Return True if ``other`` is a submodule of ``self``.
1385
+
1386
+ Examples
1387
+ ========
1388
+
1389
+ >>> from sympy.abc import x
1390
+ >>> from sympy import QQ
1391
+ >>> Q = QQ.old_poly_ring(x).free_module(2) / [(x, x)]
1392
+ >>> S = Q.submodule([1, 0])
1393
+ >>> Q.is_submodule(S)
1394
+ True
1395
+ >>> S.is_submodule(Q)
1396
+ False
1397
+ """
1398
+ if isinstance(other, QuotientModule):
1399
+ return self.killed_module == other.killed_module and \
1400
+ self.base.is_submodule(other.base)
1401
+ if isinstance(other, SubQuotientModule):
1402
+ return other.container == self
1403
+ return False
1404
+
1405
+ def submodule(self, *gens, **opts):
1406
+ """
1407
+ Generate a submodule.
1408
+
1409
+ This is the same as taking a quotient of a submodule of the base
1410
+ module.
1411
+
1412
+ Examples
1413
+ ========
1414
+
1415
+ >>> from sympy.abc import x
1416
+ >>> from sympy import QQ
1417
+ >>> Q = QQ.old_poly_ring(x).free_module(2) / [(x, x)]
1418
+ >>> Q.submodule([x, 0])
1419
+ <[x, 0] + <[x, x]>>
1420
+ """
1421
+ return SubQuotientModule(gens, self, **opts)
1422
+
1423
+ def convert(self, elem, M=None):
1424
+ """
1425
+ Convert ``elem`` into the internal representation.
1426
+
1427
+ This method is called implicitly whenever computations involve elements
1428
+ not in the internal representation.
1429
+
1430
+ Examples
1431
+ ========
1432
+
1433
+ >>> from sympy.abc import x
1434
+ >>> from sympy import QQ
1435
+ >>> F = QQ.old_poly_ring(x).free_module(2) / [(1, 2), (1, x)]
1436
+ >>> F.convert([1, 0])
1437
+ [1, 0] + <[1, 2], [1, x]>
1438
+ """
1439
+ if isinstance(elem, QuotientModuleElement):
1440
+ if elem.module is self:
1441
+ return elem
1442
+ if self.killed_module.is_submodule(elem.module.killed_module):
1443
+ return QuotientModuleElement(self, self.base.convert(elem.data))
1444
+ raise CoercionFailed
1445
+ return QuotientModuleElement(self, self.base.convert(elem))
1446
+
1447
+ def identity_hom(self):
1448
+ """
1449
+ Return the identity homomorphism on ``self``.
1450
+
1451
+ Examples
1452
+ ========
1453
+
1454
+ >>> from sympy.abc import x
1455
+ >>> from sympy import QQ
1456
+ >>> M = QQ.old_poly_ring(x).free_module(2) / [(1, 2), (1, x)]
1457
+ >>> M.identity_hom()
1458
+ Matrix([
1459
+ [1, 0], : QQ[x]**2/<[1, 2], [1, x]> -> QQ[x]**2/<[1, 2], [1, x]>
1460
+ [0, 1]])
1461
+ """
1462
+ return self.base.identity_hom().quotient_codomain(
1463
+ self.killed_module).quotient_domain(self.killed_module)
1464
+
1465
+ def quotient_hom(self):
1466
+ """
1467
+ Return the quotient homomorphism to ``self``.
1468
+
1469
+ That is, return a homomorphism representing the natural map from
1470
+ ``self.base`` to ``self``.
1471
+
1472
+ Examples
1473
+ ========
1474
+
1475
+ >>> from sympy.abc import x
1476
+ >>> from sympy import QQ
1477
+ >>> M = QQ.old_poly_ring(x).free_module(2) / [(1, 2), (1, x)]
1478
+ >>> M.quotient_hom()
1479
+ Matrix([
1480
+ [1, 0], : QQ[x]**2 -> QQ[x]**2/<[1, 2], [1, x]>
1481
+ [0, 1]])
1482
+ """
1483
+ return self.base.identity_hom().quotient_codomain(
1484
+ self.killed_module)
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