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Upload folder using huggingface_hub (part 18)

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  1. .gitattributes +23 -0
  2. .venv/lib/python3.12/site-packages/sympy/geometry/util.py +731 -0
  3. .venv/lib/python3.12/site-packages/sympy/holonomic/__init__.py +18 -0
  4. .venv/lib/python3.12/site-packages/sympy/holonomic/__pycache__/__init__.cpython-312.pyc +0 -0
  5. .venv/lib/python3.12/site-packages/sympy/holonomic/__pycache__/holonomic.cpython-312.pyc +3 -0
  6. .venv/lib/python3.12/site-packages/sympy/holonomic/__pycache__/holonomicerrors.cpython-312.pyc +0 -0
  7. .venv/lib/python3.12/site-packages/sympy/holonomic/__pycache__/numerical.cpython-312.pyc +0 -0
  8. .venv/lib/python3.12/site-packages/sympy/holonomic/__pycache__/recurrence.cpython-312.pyc +0 -0
  9. .venv/lib/python3.12/site-packages/sympy/holonomic/holonomic.py +2765 -0
  10. .venv/lib/python3.12/site-packages/sympy/holonomic/holonomicerrors.py +49 -0
  11. .venv/lib/python3.12/site-packages/sympy/holonomic/numerical.py +98 -0
  12. .venv/lib/python3.12/site-packages/sympy/holonomic/recurrence.py +342 -0
  13. .venv/lib/python3.12/site-packages/sympy/holonomic/tests/__init__.py +0 -0
  14. .venv/lib/python3.12/site-packages/sympy/holonomic/tests/__pycache__/__init__.cpython-312.pyc +0 -0
  15. .venv/lib/python3.12/site-packages/sympy/holonomic/tests/__pycache__/test_holonomic.cpython-312.pyc +0 -0
  16. .venv/lib/python3.12/site-packages/sympy/holonomic/tests/__pycache__/test_recurrence.cpython-312.pyc +0 -0
  17. .venv/lib/python3.12/site-packages/sympy/holonomic/tests/test_holonomic.py +851 -0
  18. .venv/lib/python3.12/site-packages/sympy/holonomic/tests/test_recurrence.py +41 -0
  19. .venv/lib/python3.12/site-packages/sympy/integrals/__init__.py +45 -0
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  36. .venv/lib/python3.12/site-packages/sympy/integrals/__pycache__/trigonometry.cpython-312.pyc +0 -0
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  41. .venv/lib/python3.12/site-packages/sympy/integrals/benchmarks/bench_integrate.py +21 -0
  42. .venv/lib/python3.12/site-packages/sympy/integrals/benchmarks/bench_trigintegrate.py +13 -0
  43. .venv/lib/python3.12/site-packages/sympy/integrals/deltafunctions.py +201 -0
  44. .venv/lib/python3.12/site-packages/sympy/integrals/heurisch.py +781 -0
  45. .venv/lib/python3.12/site-packages/sympy/integrals/integrals.py +1640 -0
  46. .venv/lib/python3.12/site-packages/sympy/integrals/intpoly.py +1302 -0
  47. .venv/lib/python3.12/site-packages/sympy/integrals/laplace.py +2377 -0
  48. .venv/lib/python3.12/site-packages/sympy/integrals/manualintegrate.py +2174 -0
  49. .venv/lib/python3.12/site-packages/sympy/integrals/meijerint.py +2191 -0
  50. .venv/lib/python3.12/site-packages/sympy/integrals/meijerint_doc.py +38 -0
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1
+ """Utility functions for geometrical entities.
2
+
3
+ Contains
4
+ ========
5
+ intersection
6
+ convex_hull
7
+ closest_points
8
+ farthest_points
9
+ are_coplanar
10
+ are_similar
11
+
12
+ """
13
+
14
+ from collections import deque
15
+ from math import sqrt as _sqrt
16
+
17
+ from sympy import nsimplify
18
+ from .entity import GeometryEntity
19
+ from .exceptions import GeometryError
20
+ from .point import Point, Point2D, Point3D
21
+ from sympy.core.containers import OrderedSet
22
+ from sympy.core.exprtools import factor_terms
23
+ from sympy.core.function import Function, expand_mul
24
+ from sympy.core.numbers import Float
25
+ from sympy.core.sorting import ordered
26
+ from sympy.core.symbol import Symbol
27
+ from sympy.core.singleton import S
28
+ from sympy.polys.polytools import cancel
29
+ from sympy.functions.elementary.miscellaneous import sqrt
30
+ from sympy.utilities.iterables import is_sequence
31
+
32
+ from mpmath.libmp.libmpf import prec_to_dps
33
+
34
+
35
+ def find(x, equation):
36
+ """
37
+ Checks whether a Symbol matching ``x`` is present in ``equation``
38
+ or not. If present, the matching symbol is returned, else a
39
+ ValueError is raised. If ``x`` is a string the matching symbol
40
+ will have the same name; if ``x`` is a Symbol then it will be
41
+ returned if found.
42
+
43
+ Examples
44
+ ========
45
+
46
+ >>> from sympy.geometry.util import find
47
+ >>> from sympy import Dummy
48
+ >>> from sympy.abc import x
49
+ >>> find('x', x)
50
+ x
51
+ >>> find('x', Dummy('x'))
52
+ _x
53
+
54
+ The dummy symbol is returned since it has a matching name:
55
+
56
+ >>> _.name == 'x'
57
+ True
58
+ >>> find(x, Dummy('x'))
59
+ Traceback (most recent call last):
60
+ ...
61
+ ValueError: could not find x
62
+ """
63
+
64
+ free = equation.free_symbols
65
+ xs = [i for i in free if (i.name if isinstance(x, str) else i) == x]
66
+ if not xs:
67
+ raise ValueError('could not find %s' % x)
68
+ if len(xs) != 1:
69
+ raise ValueError('ambiguous %s' % x)
70
+ return xs[0]
71
+
72
+
73
+ def _ordered_points(p):
74
+ """Return the tuple of points sorted numerically according to args"""
75
+ return tuple(sorted(p, key=lambda x: x.args))
76
+
77
+
78
+ def are_coplanar(*e):
79
+ """ Returns True if the given entities are coplanar otherwise False
80
+
81
+ Parameters
82
+ ==========
83
+
84
+ e: entities to be checked for being coplanar
85
+
86
+ Returns
87
+ =======
88
+
89
+ Boolean
90
+
91
+ Examples
92
+ ========
93
+
94
+ >>> from sympy import Point3D, Line3D
95
+ >>> from sympy.geometry.util import are_coplanar
96
+ >>> a = Line3D(Point3D(5, 0, 0), Point3D(1, -1, 1))
97
+ >>> b = Line3D(Point3D(0, -2, 0), Point3D(3, 1, 1))
98
+ >>> c = Line3D(Point3D(0, -1, 0), Point3D(5, -1, 9))
99
+ >>> are_coplanar(a, b, c)
100
+ False
101
+
102
+ """
103
+ from .line import LinearEntity3D
104
+ from .plane import Plane
105
+ # XXX update tests for coverage
106
+
107
+ e = set(e)
108
+ # first work with a Plane if present
109
+ for i in list(e):
110
+ if isinstance(i, Plane):
111
+ e.remove(i)
112
+ return all(p.is_coplanar(i) for p in e)
113
+
114
+ if all(isinstance(i, Point3D) for i in e):
115
+ if len(e) < 3:
116
+ return False
117
+
118
+ # remove pts that are collinear with 2 pts
119
+ a, b = e.pop(), e.pop()
120
+ for i in list(e):
121
+ if Point3D.are_collinear(a, b, i):
122
+ e.remove(i)
123
+
124
+ if not e:
125
+ return False
126
+ else:
127
+ # define a plane
128
+ p = Plane(a, b, e.pop())
129
+ for i in e:
130
+ if i not in p:
131
+ return False
132
+ return True
133
+ else:
134
+ pt3d = []
135
+ for i in e:
136
+ if isinstance(i, Point3D):
137
+ pt3d.append(i)
138
+ elif isinstance(i, LinearEntity3D):
139
+ pt3d.extend(i.args)
140
+ elif isinstance(i, GeometryEntity): # XXX we should have a GeometryEntity3D class so we can tell the difference between 2D and 3D -- here we just want to deal with 2D objects; if new 3D objects are encountered that we didn't handle above, an error should be raised
141
+ # all 2D objects have some Point that defines them; so convert those points to 3D pts by making z=0
142
+ for p in i.args:
143
+ if isinstance(p, Point):
144
+ pt3d.append(Point3D(*(p.args + (0,))))
145
+ return are_coplanar(*pt3d)
146
+
147
+
148
+ def are_similar(e1, e2):
149
+ """Are two geometrical entities similar.
150
+
151
+ Can one geometrical entity be uniformly scaled to the other?
152
+
153
+ Parameters
154
+ ==========
155
+
156
+ e1 : GeometryEntity
157
+ e2 : GeometryEntity
158
+
159
+ Returns
160
+ =======
161
+
162
+ are_similar : boolean
163
+
164
+ Raises
165
+ ======
166
+
167
+ GeometryError
168
+ When `e1` and `e2` cannot be compared.
169
+
170
+ Notes
171
+ =====
172
+
173
+ If the two objects are equal then they are similar.
174
+
175
+ See Also
176
+ ========
177
+
178
+ sympy.geometry.entity.GeometryEntity.is_similar
179
+
180
+ Examples
181
+ ========
182
+
183
+ >>> from sympy import Point, Circle, Triangle, are_similar
184
+ >>> c1, c2 = Circle(Point(0, 0), 4), Circle(Point(1, 4), 3)
185
+ >>> t1 = Triangle(Point(0, 0), Point(1, 0), Point(0, 1))
186
+ >>> t2 = Triangle(Point(0, 0), Point(2, 0), Point(0, 2))
187
+ >>> t3 = Triangle(Point(0, 0), Point(3, 0), Point(0, 1))
188
+ >>> are_similar(t1, t2)
189
+ True
190
+ >>> are_similar(t1, t3)
191
+ False
192
+
193
+ """
194
+ if e1 == e2:
195
+ return True
196
+ is_similar1 = getattr(e1, 'is_similar', None)
197
+ if is_similar1:
198
+ return is_similar1(e2)
199
+ is_similar2 = getattr(e2, 'is_similar', None)
200
+ if is_similar2:
201
+ return is_similar2(e1)
202
+ n1 = e1.__class__.__name__
203
+ n2 = e2.__class__.__name__
204
+ raise GeometryError(
205
+ "Cannot test similarity between %s and %s" % (n1, n2))
206
+
207
+
208
+ def centroid(*args):
209
+ """Find the centroid (center of mass) of the collection containing only Points,
210
+ Segments or Polygons. The centroid is the weighted average of the individual centroid
211
+ where the weights are the lengths (of segments) or areas (of polygons).
212
+ Overlapping regions will add to the weight of that region.
213
+
214
+ If there are no objects (or a mixture of objects) then None is returned.
215
+
216
+ See Also
217
+ ========
218
+
219
+ sympy.geometry.point.Point, sympy.geometry.line.Segment,
220
+ sympy.geometry.polygon.Polygon
221
+
222
+ Examples
223
+ ========
224
+
225
+ >>> from sympy import Point, Segment, Polygon
226
+ >>> from sympy.geometry.util import centroid
227
+ >>> p = Polygon((0, 0), (10, 0), (10, 10))
228
+ >>> q = p.translate(0, 20)
229
+ >>> p.centroid, q.centroid
230
+ (Point2D(20/3, 10/3), Point2D(20/3, 70/3))
231
+ >>> centroid(p, q)
232
+ Point2D(20/3, 40/3)
233
+ >>> p, q = Segment((0, 0), (2, 0)), Segment((0, 0), (2, 2))
234
+ >>> centroid(p, q)
235
+ Point2D(1, 2 - sqrt(2))
236
+ >>> centroid(Point(0, 0), Point(2, 0))
237
+ Point2D(1, 0)
238
+
239
+ Stacking 3 polygons on top of each other effectively triples the
240
+ weight of that polygon:
241
+
242
+ >>> p = Polygon((0, 0), (1, 0), (1, 1), (0, 1))
243
+ >>> q = Polygon((1, 0), (3, 0), (3, 1), (1, 1))
244
+ >>> centroid(p, q)
245
+ Point2D(3/2, 1/2)
246
+ >>> centroid(p, p, p, q) # centroid x-coord shifts left
247
+ Point2D(11/10, 1/2)
248
+
249
+ Stacking the squares vertically above and below p has the same
250
+ effect:
251
+
252
+ >>> centroid(p, p.translate(0, 1), p.translate(0, -1), q)
253
+ Point2D(11/10, 1/2)
254
+
255
+ """
256
+ from .line import Segment
257
+ from .polygon import Polygon
258
+ if args:
259
+ if all(isinstance(g, Point) for g in args):
260
+ c = Point(0, 0)
261
+ for g in args:
262
+ c += g
263
+ den = len(args)
264
+ elif all(isinstance(g, Segment) for g in args):
265
+ c = Point(0, 0)
266
+ L = 0
267
+ for g in args:
268
+ l = g.length
269
+ c += g.midpoint*l
270
+ L += l
271
+ den = L
272
+ elif all(isinstance(g, Polygon) for g in args):
273
+ c = Point(0, 0)
274
+ A = 0
275
+ for g in args:
276
+ a = g.area
277
+ c += g.centroid*a
278
+ A += a
279
+ den = A
280
+ c /= den
281
+ return c.func(*[i.simplify() for i in c.args])
282
+
283
+
284
+ def closest_points(*args):
285
+ """Return the subset of points from a set of points that were
286
+ the closest to each other in the 2D plane.
287
+
288
+ Parameters
289
+ ==========
290
+
291
+ args
292
+ A collection of Points on 2D plane.
293
+
294
+ Notes
295
+ =====
296
+
297
+ This can only be performed on a set of points whose coordinates can
298
+ be ordered on the number line. If there are no ties then a single
299
+ pair of Points will be in the set.
300
+
301
+ Examples
302
+ ========
303
+
304
+ >>> from sympy import closest_points, Triangle
305
+ >>> Triangle(sss=(3, 4, 5)).args
306
+ (Point2D(0, 0), Point2D(3, 0), Point2D(3, 4))
307
+ >>> closest_points(*_)
308
+ {(Point2D(0, 0), Point2D(3, 0))}
309
+
310
+ References
311
+ ==========
312
+
313
+ .. [1] https://www.cs.mcgill.ca/~cs251/ClosestPair/ClosestPairPS.html
314
+
315
+ .. [2] Sweep line algorithm
316
+ https://en.wikipedia.org/wiki/Sweep_line_algorithm
317
+
318
+ """
319
+ p = [Point2D(i) for i in set(args)]
320
+ if len(p) < 2:
321
+ raise ValueError('At least 2 distinct points must be given.')
322
+
323
+ try:
324
+ p.sort(key=lambda x: x.args)
325
+ except TypeError:
326
+ raise ValueError("The points could not be sorted.")
327
+
328
+ if not all(i.is_Rational for j in p for i in j.args):
329
+ def hypot(x, y):
330
+ arg = x*x + y*y
331
+ if arg.is_Rational:
332
+ return _sqrt(arg)
333
+ return sqrt(arg)
334
+ else:
335
+ from math import hypot
336
+
337
+ rv = [(0, 1)]
338
+ best_dist = hypot(p[1].x - p[0].x, p[1].y - p[0].y)
339
+ left = 0
340
+ box = deque([0, 1])
341
+ for i in range(2, len(p)):
342
+ while left < i and p[i][0] - p[left][0] > best_dist:
343
+ box.popleft()
344
+ left += 1
345
+
346
+ for j in box:
347
+ d = hypot(p[i].x - p[j].x, p[i].y - p[j].y)
348
+ if d < best_dist:
349
+ rv = [(j, i)]
350
+ elif d == best_dist:
351
+ rv.append((j, i))
352
+ else:
353
+ continue
354
+ best_dist = d
355
+ box.append(i)
356
+
357
+ return {tuple([p[i] for i in pair]) for pair in rv}
358
+
359
+
360
+ def convex_hull(*args, polygon=True):
361
+ """The convex hull surrounding the Points contained in the list of entities.
362
+
363
+ Parameters
364
+ ==========
365
+
366
+ args : a collection of Points, Segments and/or Polygons
367
+
368
+ Optional parameters
369
+ ===================
370
+
371
+ polygon : Boolean. If True, returns a Polygon, if false a tuple, see below.
372
+ Default is True.
373
+
374
+ Returns
375
+ =======
376
+
377
+ convex_hull : Polygon if ``polygon`` is True else as a tuple `(U, L)` where
378
+ ``L`` and ``U`` are the lower and upper hulls, respectively.
379
+
380
+ Notes
381
+ =====
382
+
383
+ This can only be performed on a set of points whose coordinates can
384
+ be ordered on the number line.
385
+
386
+ See Also
387
+ ========
388
+
389
+ sympy.geometry.point.Point, sympy.geometry.polygon.Polygon
390
+
391
+ Examples
392
+ ========
393
+
394
+ >>> from sympy import convex_hull
395
+ >>> points = [(1, 1), (1, 2), (3, 1), (-5, 2), (15, 4)]
396
+ >>> convex_hull(*points)
397
+ Polygon(Point2D(-5, 2), Point2D(1, 1), Point2D(3, 1), Point2D(15, 4))
398
+ >>> convex_hull(*points, **dict(polygon=False))
399
+ ([Point2D(-5, 2), Point2D(15, 4)],
400
+ [Point2D(-5, 2), Point2D(1, 1), Point2D(3, 1), Point2D(15, 4)])
401
+
402
+ References
403
+ ==========
404
+
405
+ .. [1] https://en.wikipedia.org/wiki/Graham_scan
406
+
407
+ .. [2] Andrew's Monotone Chain Algorithm
408
+ (A.M. Andrew,
409
+ "Another Efficient Algorithm for Convex Hulls in Two Dimensions", 1979)
410
+ https://web.archive.org/web/20210511015444/http://geomalgorithms.com/a10-_hull-1.html
411
+
412
+ """
413
+ from .line import Segment
414
+ from .polygon import Polygon
415
+ p = OrderedSet()
416
+ for e in args:
417
+ if not isinstance(e, GeometryEntity):
418
+ try:
419
+ e = Point(e)
420
+ except NotImplementedError:
421
+ raise ValueError('%s is not a GeometryEntity and cannot be made into Point' % str(e))
422
+ if isinstance(e, Point):
423
+ p.add(e)
424
+ elif isinstance(e, Segment):
425
+ p.update(e.points)
426
+ elif isinstance(e, Polygon):
427
+ p.update(e.vertices)
428
+ else:
429
+ raise NotImplementedError(
430
+ 'Convex hull for %s not implemented.' % type(e))
431
+
432
+ # make sure all our points are of the same dimension
433
+ if any(len(x) != 2 for x in p):
434
+ raise ValueError('Can only compute the convex hull in two dimensions')
435
+
436
+ p = list(p)
437
+ if len(p) == 1:
438
+ return p[0] if polygon else (p[0], None)
439
+ elif len(p) == 2:
440
+ s = Segment(p[0], p[1])
441
+ return s if polygon else (s, None)
442
+
443
+ def _orientation(p, q, r):
444
+ '''Return positive if p-q-r are clockwise, neg if ccw, zero if
445
+ collinear.'''
446
+ return (q.y - p.y)*(r.x - p.x) - (q.x - p.x)*(r.y - p.y)
447
+
448
+ # scan to find upper and lower convex hulls of a set of 2d points.
449
+ U = []
450
+ L = []
451
+ try:
452
+ p.sort(key=lambda x: x.args)
453
+ except TypeError:
454
+ raise ValueError("The points could not be sorted.")
455
+ for p_i in p:
456
+ while len(U) > 1 and _orientation(U[-2], U[-1], p_i) <= 0:
457
+ U.pop()
458
+ while len(L) > 1 and _orientation(L[-2], L[-1], p_i) >= 0:
459
+ L.pop()
460
+ U.append(p_i)
461
+ L.append(p_i)
462
+ U.reverse()
463
+ convexHull = tuple(L + U[1:-1])
464
+
465
+ if len(convexHull) == 2:
466
+ s = Segment(convexHull[0], convexHull[1])
467
+ return s if polygon else (s, None)
468
+ if polygon:
469
+ return Polygon(*convexHull)
470
+ else:
471
+ U.reverse()
472
+ return (U, L)
473
+
474
+ def farthest_points(*args):
475
+ """Return the subset of points from a set of points that were
476
+ the furthest apart from each other in the 2D plane.
477
+
478
+ Parameters
479
+ ==========
480
+
481
+ args
482
+ A collection of Points on 2D plane.
483
+
484
+ Notes
485
+ =====
486
+
487
+ This can only be performed on a set of points whose coordinates can
488
+ be ordered on the number line. If there are no ties then a single
489
+ pair of Points will be in the set.
490
+
491
+ Examples
492
+ ========
493
+
494
+ >>> from sympy.geometry import farthest_points, Triangle
495
+ >>> Triangle(sss=(3, 4, 5)).args
496
+ (Point2D(0, 0), Point2D(3, 0), Point2D(3, 4))
497
+ >>> farthest_points(*_)
498
+ {(Point2D(0, 0), Point2D(3, 4))}
499
+
500
+ References
501
+ ==========
502
+
503
+ .. [1] https://code.activestate.com/recipes/117225-convex-hull-and-diameter-of-2d-point-sets/
504
+
505
+ .. [2] Rotating Callipers Technique
506
+ https://en.wikipedia.org/wiki/Rotating_calipers
507
+
508
+ """
509
+
510
+ def rotatingCalipers(Points):
511
+ U, L = convex_hull(*Points, **{"polygon": False})
512
+
513
+ if L is None:
514
+ if isinstance(U, Point):
515
+ raise ValueError('At least two distinct points must be given.')
516
+ yield U.args
517
+ else:
518
+ i = 0
519
+ j = len(L) - 1
520
+ while i < len(U) - 1 or j > 0:
521
+ yield U[i], L[j]
522
+ # if all the way through one side of hull, advance the other side
523
+ if i == len(U) - 1:
524
+ j -= 1
525
+ elif j == 0:
526
+ i += 1
527
+ # still points left on both lists, compare slopes of next hull edges
528
+ # being careful to avoid divide-by-zero in slope calculation
529
+ elif (U[i+1].y - U[i].y) * (L[j].x - L[j-1].x) > \
530
+ (L[j].y - L[j-1].y) * (U[i+1].x - U[i].x):
531
+ i += 1
532
+ else:
533
+ j -= 1
534
+
535
+ p = [Point2D(i) for i in set(args)]
536
+
537
+ if not all(i.is_Rational for j in p for i in j.args):
538
+ def hypot(x, y):
539
+ arg = x*x + y*y
540
+ if arg.is_Rational:
541
+ return _sqrt(arg)
542
+ return sqrt(arg)
543
+ else:
544
+ from math import hypot
545
+
546
+ rv = []
547
+ diam = 0
548
+ for pair in rotatingCalipers(args):
549
+ h, q = _ordered_points(pair)
550
+ d = hypot(h.x - q.x, h.y - q.y)
551
+ if d > diam:
552
+ rv = [(h, q)]
553
+ elif d == diam:
554
+ rv.append((h, q))
555
+ else:
556
+ continue
557
+ diam = d
558
+
559
+ return set(rv)
560
+
561
+
562
+ def idiff(eq, y, x, n=1):
563
+ """Return ``dy/dx`` assuming that ``eq == 0``.
564
+
565
+ Parameters
566
+ ==========
567
+
568
+ y : the dependent variable or a list of dependent variables (with y first)
569
+ x : the variable that the derivative is being taken with respect to
570
+ n : the order of the derivative (default is 1)
571
+
572
+ Examples
573
+ ========
574
+
575
+ >>> from sympy.abc import x, y, a
576
+ >>> from sympy.geometry.util import idiff
577
+
578
+ >>> circ = x**2 + y**2 - 4
579
+ >>> idiff(circ, y, x)
580
+ -x/y
581
+ >>> idiff(circ, y, x, 2).simplify()
582
+ (-x**2 - y**2)/y**3
583
+
584
+ Here, ``a`` is assumed to be independent of ``x``:
585
+
586
+ >>> idiff(x + a + y, y, x)
587
+ -1
588
+
589
+ Now the x-dependence of ``a`` is made explicit by listing ``a`` after
590
+ ``y`` in a list.
591
+
592
+ >>> idiff(x + a + y, [y, a], x)
593
+ -Derivative(a, x) - 1
594
+
595
+ See Also
596
+ ========
597
+
598
+ sympy.core.function.Derivative: represents unevaluated derivatives
599
+ sympy.core.function.diff: explicitly differentiates wrt symbols
600
+
601
+ """
602
+ if is_sequence(y):
603
+ dep = set(y)
604
+ y = y[0]
605
+ elif isinstance(y, Symbol):
606
+ dep = {y}
607
+ elif isinstance(y, Function):
608
+ pass
609
+ else:
610
+ raise ValueError("expecting x-dependent symbol(s) or function(s) but got: %s" % y)
611
+
612
+ f = {s: Function(s.name)(x) for s in eq.free_symbols
613
+ if s != x and s in dep}
614
+
615
+ if isinstance(y, Symbol):
616
+ dydx = Function(y.name)(x).diff(x)
617
+ else:
618
+ dydx = y.diff(x)
619
+
620
+ eq = eq.subs(f)
621
+ derivs = {}
622
+ for i in range(n):
623
+ # equation will be linear in dydx, a*dydx + b, so dydx = -b/a
624
+ deq = eq.diff(x)
625
+ b = deq.xreplace({dydx: S.Zero})
626
+ a = (deq - b).xreplace({dydx: S.One})
627
+ yp = factor_terms(expand_mul(cancel((-b/a).subs(derivs)), deep=False))
628
+ if i == n - 1:
629
+ return yp.subs([(v, k) for k, v in f.items()])
630
+ derivs[dydx] = yp
631
+ eq = dydx - yp
632
+ dydx = dydx.diff(x)
633
+
634
+
635
+ def intersection(*entities, pairwise=False, **kwargs):
636
+ """The intersection of a collection of GeometryEntity instances.
637
+
638
+ Parameters
639
+ ==========
640
+ entities : sequence of GeometryEntity
641
+ pairwise (keyword argument) : Can be either True or False
642
+
643
+ Returns
644
+ =======
645
+ intersection : list of GeometryEntity
646
+
647
+ Raises
648
+ ======
649
+ NotImplementedError
650
+ When unable to calculate intersection.
651
+
652
+ Notes
653
+ =====
654
+ The intersection of any geometrical entity with itself should return
655
+ a list with one item: the entity in question.
656
+ An intersection requires two or more entities. If only a single
657
+ entity is given then the function will return an empty list.
658
+ It is possible for `intersection` to miss intersections that one
659
+ knows exists because the required quantities were not fully
660
+ simplified internally.
661
+ Reals should be converted to Rationals, e.g. Rational(str(real_num))
662
+ or else failures due to floating point issues may result.
663
+
664
+ Case 1: When the keyword argument 'pairwise' is False (default value):
665
+ In this case, the function returns a list of intersections common to
666
+ all entities.
667
+
668
+ Case 2: When the keyword argument 'pairwise' is True:
669
+ In this case, the functions returns a list intersections that occur
670
+ between any pair of entities.
671
+
672
+ See Also
673
+ ========
674
+
675
+ sympy.geometry.entity.GeometryEntity.intersection
676
+
677
+ Examples
678
+ ========
679
+
680
+ >>> from sympy import Ray, Circle, intersection
681
+ >>> c = Circle((0, 1), 1)
682
+ >>> intersection(c, c.center)
683
+ []
684
+ >>> right = Ray((0, 0), (1, 0))
685
+ >>> up = Ray((0, 0), (0, 1))
686
+ >>> intersection(c, right, up)
687
+ [Point2D(0, 0)]
688
+ >>> intersection(c, right, up, pairwise=True)
689
+ [Point2D(0, 0), Point2D(0, 2)]
690
+ >>> left = Ray((1, 0), (0, 0))
691
+ >>> intersection(right, left)
692
+ [Segment2D(Point2D(0, 0), Point2D(1, 0))]
693
+
694
+ """
695
+ if len(entities) <= 1:
696
+ return []
697
+
698
+ entities = list(entities)
699
+ prec = None
700
+ for i, e in enumerate(entities):
701
+ if not isinstance(e, GeometryEntity):
702
+ # entities may be an immutable tuple
703
+ e = Point(e)
704
+ # convert to exact Rationals
705
+ d = {}
706
+ for f in e.atoms(Float):
707
+ prec = f._prec if prec is None else min(f._prec, prec)
708
+ d.setdefault(f, nsimplify(f, rational=True))
709
+ entities[i] = e.xreplace(d)
710
+
711
+ if not pairwise:
712
+ # find the intersection common to all objects
713
+ res = entities[0].intersection(entities[1])
714
+ for entity in entities[2:]:
715
+ newres = []
716
+ for x in res:
717
+ newres.extend(x.intersection(entity))
718
+ res = newres
719
+ else:
720
+ # find all pairwise intersections
721
+ ans = []
722
+ for j in range(len(entities)):
723
+ for k in range(j + 1, len(entities)):
724
+ ans.extend(intersection(entities[j], entities[k]))
725
+ res = list(ordered(set(ans)))
726
+
727
+ # convert back to Floats
728
+ if prec is not None:
729
+ p = prec_to_dps(prec)
730
+ res = [i.n(p) for i in res]
731
+ return res
.venv/lib/python3.12/site-packages/sympy/holonomic/__init__.py ADDED
@@ -0,0 +1,18 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ r"""
2
+ The :py:mod:`~sympy.holonomic` module is intended to deal with holonomic functions along
3
+ with various operations on them like addition, multiplication, composition,
4
+ integration and differentiation. The module also implements various kinds of
5
+ conversions such as converting holonomic functions to a different form and the
6
+ other way around.
7
+ """
8
+
9
+ from .holonomic import (DifferentialOperator, HolonomicFunction, DifferentialOperators,
10
+ from_hyper, from_meijerg, expr_to_holonomic)
11
+ from .recurrence import RecurrenceOperators, RecurrenceOperator, HolonomicSequence
12
+
13
+ __all__ = [
14
+ 'DifferentialOperator', 'HolonomicFunction', 'DifferentialOperators',
15
+ 'from_hyper', 'from_meijerg', 'expr_to_holonomic',
16
+
17
+ 'RecurrenceOperators', 'RecurrenceOperator', 'HolonomicSequence',
18
+ ]
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.venv/lib/python3.12/site-packages/sympy/holonomic/holonomic.py ADDED
@@ -0,0 +1,2765 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ """
2
+ This module implements Holonomic Functions and
3
+ various operations on them.
4
+ """
5
+
6
+ from sympy.core import Add, Mul, Pow
7
+ from sympy.core.numbers import (NaN, Infinity, NegativeInfinity, Float, I, pi,
8
+ equal_valued, int_valued)
9
+ from sympy.core.singleton import S
10
+ from sympy.core.sorting import ordered
11
+ from sympy.core.symbol import Dummy, Symbol
12
+ from sympy.core.sympify import sympify
13
+ from sympy.functions.combinatorial.factorials import binomial, factorial, rf
14
+ from sympy.functions.elementary.exponential import exp_polar, exp, log
15
+ from sympy.functions.elementary.hyperbolic import (cosh, sinh)
16
+ from sympy.functions.elementary.miscellaneous import sqrt
17
+ from sympy.functions.elementary.trigonometric import (cos, sin, sinc)
18
+ from sympy.functions.special.error_functions import (Ci, Shi, Si, erf, erfc, erfi)
19
+ from sympy.functions.special.gamma_functions import gamma
20
+ from sympy.functions.special.hyper import hyper, meijerg
21
+ from sympy.integrals import meijerint
22
+ from sympy.matrices import Matrix
23
+ from sympy.polys.rings import PolyElement
24
+ from sympy.polys.fields import FracElement
25
+ from sympy.polys.domains import QQ, RR
26
+ from sympy.polys.polyclasses import DMF
27
+ from sympy.polys.polyroots import roots
28
+ from sympy.polys.polytools import Poly
29
+ from sympy.polys.matrices import DomainMatrix
30
+ from sympy.printing import sstr
31
+ from sympy.series.limits import limit
32
+ from sympy.series.order import Order
33
+ from sympy.simplify.hyperexpand import hyperexpand
34
+ from sympy.simplify.simplify import nsimplify
35
+ from sympy.solvers.solvers import solve
36
+
37
+ from .recurrence import HolonomicSequence, RecurrenceOperator, RecurrenceOperators
38
+ from .holonomicerrors import (NotPowerSeriesError, NotHyperSeriesError,
39
+ SingularityError, NotHolonomicError)
40
+
41
+
42
+ def _find_nonzero_solution(r, homosys):
43
+ ones = lambda shape: DomainMatrix.ones(shape, r.domain)
44
+ particular, nullspace = r._solve(homosys)
45
+ nullity = nullspace.shape[0]
46
+ nullpart = ones((1, nullity)) * nullspace
47
+ sol = (particular + nullpart).transpose()
48
+ return sol
49
+
50
+
51
+
52
+ def DifferentialOperators(base, generator):
53
+ r"""
54
+ This function is used to create annihilators using ``Dx``.
55
+
56
+ Explanation
57
+ ===========
58
+
59
+ Returns an Algebra of Differential Operators also called Weyl Algebra
60
+ and the operator for differentiation i.e. the ``Dx`` operator.
61
+
62
+ Parameters
63
+ ==========
64
+
65
+ base:
66
+ Base polynomial ring for the algebra.
67
+ The base polynomial ring is the ring of polynomials in :math:`x` that
68
+ will appear as coefficients in the operators.
69
+ generator:
70
+ Generator of the algebra which can
71
+ be either a noncommutative ``Symbol`` or a string. e.g. "Dx" or "D".
72
+
73
+ Examples
74
+ ========
75
+
76
+ >>> from sympy import ZZ
77
+ >>> from sympy.abc import x
78
+ >>> from sympy.holonomic.holonomic import DifferentialOperators
79
+ >>> R, Dx = DifferentialOperators(ZZ.old_poly_ring(x), 'Dx')
80
+ >>> R
81
+ Univariate Differential Operator Algebra in intermediate Dx over the base ring ZZ[x]
82
+ >>> Dx*x
83
+ (1) + (x)*Dx
84
+ """
85
+
86
+ ring = DifferentialOperatorAlgebra(base, generator)
87
+ return (ring, ring.derivative_operator)
88
+
89
+
90
+ class DifferentialOperatorAlgebra:
91
+ r"""
92
+ An Ore Algebra is a set of noncommutative polynomials in the
93
+ intermediate ``Dx`` and coefficients in a base polynomial ring :math:`A`.
94
+ It follows the commutation rule:
95
+
96
+ .. math ::
97
+ Dxa = \sigma(a)Dx + \delta(a)
98
+
99
+ for :math:`a \subset A`.
100
+
101
+ Where :math:`\sigma: A \Rightarrow A` is an endomorphism and :math:`\delta: A \rightarrow A`
102
+ is a skew-derivation i.e. :math:`\delta(ab) = \delta(a) b + \sigma(a) \delta(b)`.
103
+
104
+ If one takes the sigma as identity map and delta as the standard derivation
105
+ then it becomes the algebra of Differential Operators also called
106
+ a Weyl Algebra i.e. an algebra whose elements are Differential Operators.
107
+
108
+ This class represents a Weyl Algebra and serves as the parent ring for
109
+ Differential Operators.
110
+
111
+ Examples
112
+ ========
113
+
114
+ >>> from sympy import ZZ
115
+ >>> from sympy import symbols
116
+ >>> from sympy.holonomic.holonomic import DifferentialOperators
117
+ >>> x = symbols('x')
118
+ >>> R, Dx = DifferentialOperators(ZZ.old_poly_ring(x), 'Dx')
119
+ >>> R
120
+ Univariate Differential Operator Algebra in intermediate Dx over the base ring
121
+ ZZ[x]
122
+
123
+ See Also
124
+ ========
125
+
126
+ DifferentialOperator
127
+ """
128
+
129
+ def __init__(self, base, generator):
130
+ # the base polynomial ring for the algebra
131
+ self.base = base
132
+ # the operator representing differentiation i.e. `Dx`
133
+ self.derivative_operator = DifferentialOperator(
134
+ [base.zero, base.one], self)
135
+
136
+ if generator is None:
137
+ self.gen_symbol = Symbol('Dx', commutative=False)
138
+ else:
139
+ if isinstance(generator, str):
140
+ self.gen_symbol = Symbol(generator, commutative=False)
141
+ elif isinstance(generator, Symbol):
142
+ self.gen_symbol = generator
143
+
144
+ def __str__(self):
145
+ string = 'Univariate Differential Operator Algebra in intermediate '\
146
+ + sstr(self.gen_symbol) + ' over the base ring ' + \
147
+ (self.base).__str__()
148
+
149
+ return string
150
+
151
+ __repr__ = __str__
152
+
153
+ def __eq__(self, other):
154
+ return self.base == other.base and \
155
+ self.gen_symbol == other.gen_symbol
156
+
157
+
158
+ class DifferentialOperator:
159
+ """
160
+ Differential Operators are elements of Weyl Algebra. The Operators
161
+ are defined by a list of polynomials in the base ring and the
162
+ parent ring of the Operator i.e. the algebra it belongs to.
163
+
164
+ Explanation
165
+ ===========
166
+
167
+ Takes a list of polynomials for each power of ``Dx`` and the
168
+ parent ring which must be an instance of DifferentialOperatorAlgebra.
169
+
170
+ A Differential Operator can be created easily using
171
+ the operator ``Dx``. See examples below.
172
+
173
+ Examples
174
+ ========
175
+
176
+ >>> from sympy.holonomic.holonomic import DifferentialOperator, DifferentialOperators
177
+ >>> from sympy import ZZ
178
+ >>> from sympy import symbols
179
+ >>> x = symbols('x')
180
+ >>> R, Dx = DifferentialOperators(ZZ.old_poly_ring(x),'Dx')
181
+
182
+ >>> DifferentialOperator([0, 1, x**2], R)
183
+ (1)*Dx + (x**2)*Dx**2
184
+
185
+ >>> (x*Dx*x + 1 - Dx**2)**2
186
+ (2*x**2 + 2*x + 1) + (4*x**3 + 2*x**2 - 4)*Dx + (x**4 - 6*x - 2)*Dx**2 + (-2*x**2)*Dx**3 + (1)*Dx**4
187
+
188
+ See Also
189
+ ========
190
+
191
+ DifferentialOperatorAlgebra
192
+ """
193
+
194
+ _op_priority = 20
195
+
196
+ def __init__(self, list_of_poly, parent):
197
+ """
198
+ Parameters
199
+ ==========
200
+
201
+ list_of_poly:
202
+ List of polynomials belonging to the base ring of the algebra.
203
+ parent:
204
+ Parent algebra of the operator.
205
+ """
206
+
207
+ # the parent ring for this operator
208
+ # must be an DifferentialOperatorAlgebra object
209
+ self.parent = parent
210
+ base = self.parent.base
211
+ self.x = base.gens[0] if isinstance(base.gens[0], Symbol) else base.gens[0][0]
212
+ # sequence of polynomials in x for each power of Dx
213
+ # the list should not have trailing zeroes
214
+ # represents the operator
215
+ # convert the expressions into ring elements using from_sympy
216
+ for i, j in enumerate(list_of_poly):
217
+ if not isinstance(j, base.dtype):
218
+ list_of_poly[i] = base.from_sympy(sympify(j))
219
+ else:
220
+ list_of_poly[i] = base.from_sympy(base.to_sympy(j))
221
+
222
+ self.listofpoly = list_of_poly
223
+ # highest power of `Dx`
224
+ self.order = len(self.listofpoly) - 1
225
+
226
+ def __mul__(self, other):
227
+ """
228
+ Multiplies two DifferentialOperator and returns another
229
+ DifferentialOperator instance using the commutation rule
230
+ Dx*a = a*Dx + a'
231
+ """
232
+
233
+ listofself = self.listofpoly
234
+ if isinstance(other, DifferentialOperator):
235
+ listofother = other.listofpoly
236
+ elif isinstance(other, self.parent.base.dtype):
237
+ listofother = [other]
238
+ else:
239
+ listofother = [self.parent.base.from_sympy(sympify(other))]
240
+
241
+ # multiplies a polynomial `b` with a list of polynomials
242
+ def _mul_dmp_diffop(b, listofother):
243
+ if isinstance(listofother, list):
244
+ return [i * b for i in listofother]
245
+ return [b * listofother]
246
+
247
+ sol = _mul_dmp_diffop(listofself[0], listofother)
248
+
249
+ # compute Dx^i * b
250
+ def _mul_Dxi_b(b):
251
+ sol1 = [self.parent.base.zero]
252
+ sol2 = []
253
+
254
+ if isinstance(b, list):
255
+ for i in b:
256
+ sol1.append(i)
257
+ sol2.append(i.diff())
258
+ else:
259
+ sol1.append(self.parent.base.from_sympy(b))
260
+ sol2.append(self.parent.base.from_sympy(b).diff())
261
+
262
+ return _add_lists(sol1, sol2)
263
+
264
+ for i in range(1, len(listofself)):
265
+ # find Dx^i * b in ith iteration
266
+ listofother = _mul_Dxi_b(listofother)
267
+ # solution = solution + listofself[i] * (Dx^i * b)
268
+ sol = _add_lists(sol, _mul_dmp_diffop(listofself[i], listofother))
269
+
270
+ return DifferentialOperator(sol, self.parent)
271
+
272
+ def __rmul__(self, other):
273
+ if not isinstance(other, DifferentialOperator):
274
+
275
+ if not isinstance(other, self.parent.base.dtype):
276
+ other = (self.parent.base).from_sympy(sympify(other))
277
+
278
+ sol = [other * j for j in self.listofpoly]
279
+ return DifferentialOperator(sol, self.parent)
280
+
281
+ def __add__(self, other):
282
+ if isinstance(other, DifferentialOperator):
283
+
284
+ sol = _add_lists(self.listofpoly, other.listofpoly)
285
+ return DifferentialOperator(sol, self.parent)
286
+
287
+ list_self = self.listofpoly
288
+ if not isinstance(other, self.parent.base.dtype):
289
+ list_other = [((self.parent).base).from_sympy(sympify(other))]
290
+ else:
291
+ list_other = [other]
292
+ sol = [list_self[0] + list_other[0]] + list_self[1:]
293
+ return DifferentialOperator(sol, self.parent)
294
+
295
+ __radd__ = __add__
296
+
297
+ def __sub__(self, other):
298
+ return self + (-1) * other
299
+
300
+ def __rsub__(self, other):
301
+ return (-1) * self + other
302
+
303
+ def __neg__(self):
304
+ return -1 * self
305
+
306
+ def __truediv__(self, other):
307
+ return self * (S.One / other)
308
+
309
+ def __pow__(self, n):
310
+ if n == 1:
311
+ return self
312
+ result = DifferentialOperator([self.parent.base.one], self.parent)
313
+ if n == 0:
314
+ return result
315
+ # if self is `Dx`
316
+ if self.listofpoly == self.parent.derivative_operator.listofpoly:
317
+ sol = [self.parent.base.zero]*n + [self.parent.base.one]
318
+ return DifferentialOperator(sol, self.parent)
319
+ x = self
320
+ while True:
321
+ if n % 2:
322
+ result *= x
323
+ n >>= 1
324
+ if not n:
325
+ break
326
+ x *= x
327
+ return result
328
+
329
+ def __str__(self):
330
+ listofpoly = self.listofpoly
331
+ print_str = ''
332
+
333
+ for i, j in enumerate(listofpoly):
334
+ if j == self.parent.base.zero:
335
+ continue
336
+
337
+ j = self.parent.base.to_sympy(j)
338
+
339
+ if i == 0:
340
+ print_str += '(' + sstr(j) + ')'
341
+ continue
342
+
343
+ if print_str:
344
+ print_str += ' + '
345
+
346
+ if i == 1:
347
+ print_str += '(' + sstr(j) + ')*%s' %(self.parent.gen_symbol)
348
+ continue
349
+
350
+ print_str += '(' + sstr(j) + ')' + '*%s**' %(self.parent.gen_symbol) + sstr(i)
351
+
352
+ return print_str
353
+
354
+ __repr__ = __str__
355
+
356
+ def __eq__(self, other):
357
+ if isinstance(other, DifferentialOperator):
358
+ return self.listofpoly == other.listofpoly and \
359
+ self.parent == other.parent
360
+ return self.listofpoly[0] == other and \
361
+ all(i is self.parent.base.zero for i in self.listofpoly[1:])
362
+
363
+ def is_singular(self, x0):
364
+ """
365
+ Checks if the differential equation is singular at x0.
366
+ """
367
+
368
+ base = self.parent.base
369
+ return x0 in roots(base.to_sympy(self.listofpoly[-1]), self.x)
370
+
371
+
372
+ class HolonomicFunction:
373
+ r"""
374
+ A Holonomic Function is a solution to a linear homogeneous ordinary
375
+ differential equation with polynomial coefficients. This differential
376
+ equation can also be represented by an annihilator i.e. a Differential
377
+ Operator ``L`` such that :math:`L.f = 0`. For uniqueness of these functions,
378
+ initial conditions can also be provided along with the annihilator.
379
+
380
+ Explanation
381
+ ===========
382
+
383
+ Holonomic functions have closure properties and thus forms a ring.
384
+ Given two Holonomic Functions f and g, their sum, product,
385
+ integral and derivative is also a Holonomic Function.
386
+
387
+ For ordinary points initial condition should be a vector of values of
388
+ the derivatives i.e. :math:`[y(x_0), y'(x_0), y''(x_0) ... ]`.
389
+
390
+ For regular singular points initial conditions can also be provided in this
391
+ format:
392
+ :math:`{s0: [C_0, C_1, ...], s1: [C^1_0, C^1_1, ...], ...}`
393
+ where s0, s1, ... are the roots of indicial equation and vectors
394
+ :math:`[C_0, C_1, ...], [C^0_0, C^0_1, ...], ...` are the corresponding initial
395
+ terms of the associated power series. See Examples below.
396
+
397
+ Examples
398
+ ========
399
+
400
+ >>> from sympy.holonomic.holonomic import HolonomicFunction, DifferentialOperators
401
+ >>> from sympy import QQ
402
+ >>> from sympy import symbols, S
403
+ >>> x = symbols('x')
404
+ >>> R, Dx = DifferentialOperators(QQ.old_poly_ring(x),'Dx')
405
+
406
+ >>> p = HolonomicFunction(Dx - 1, x, 0, [1]) # e^x
407
+ >>> q = HolonomicFunction(Dx**2 + 1, x, 0, [0, 1]) # sin(x)
408
+
409
+ >>> p + q # annihilator of e^x + sin(x)
410
+ HolonomicFunction((-1) + (1)*Dx + (-1)*Dx**2 + (1)*Dx**3, x, 0, [1, 2, 1])
411
+
412
+ >>> p * q # annihilator of e^x * sin(x)
413
+ HolonomicFunction((2) + (-2)*Dx + (1)*Dx**2, x, 0, [0, 1])
414
+
415
+ An example of initial conditions for regular singular points,
416
+ the indicial equation has only one root `1/2`.
417
+
418
+ >>> HolonomicFunction(-S(1)/2 + x*Dx, x, 0, {S(1)/2: [1]})
419
+ HolonomicFunction((-1/2) + (x)*Dx, x, 0, {1/2: [1]})
420
+
421
+ >>> HolonomicFunction(-S(1)/2 + x*Dx, x, 0, {S(1)/2: [1]}).to_expr()
422
+ sqrt(x)
423
+
424
+ To plot a Holonomic Function, one can use `.evalf()` for numerical
425
+ computation. Here's an example on `sin(x)**2/x` using numpy and matplotlib.
426
+
427
+ >>> import sympy.holonomic # doctest: +SKIP
428
+ >>> from sympy import var, sin # doctest: +SKIP
429
+ >>> import matplotlib.pyplot as plt # doctest: +SKIP
430
+ >>> import numpy as np # doctest: +SKIP
431
+ >>> var("x") # doctest: +SKIP
432
+ >>> r = np.linspace(1, 5, 100) # doctest: +SKIP
433
+ >>> y = sympy.holonomic.expr_to_holonomic(sin(x)**2/x, x0=1).evalf(r) # doctest: +SKIP
434
+ >>> plt.plot(r, y, label="holonomic function") # doctest: +SKIP
435
+ >>> plt.show() # doctest: +SKIP
436
+
437
+ """
438
+
439
+ _op_priority = 20
440
+
441
+ def __init__(self, annihilator, x, x0=0, y0=None):
442
+ """
443
+
444
+ Parameters
445
+ ==========
446
+
447
+ annihilator:
448
+ Annihilator of the Holonomic Function, represented by a
449
+ `DifferentialOperator` object.
450
+ x:
451
+ Variable of the function.
452
+ x0:
453
+ The point at which initial conditions are stored.
454
+ Generally an integer.
455
+ y0:
456
+ The initial condition. The proper format for the initial condition
457
+ is described in class docstring. To make the function unique,
458
+ length of the vector `y0` should be equal to or greater than the
459
+ order of differential equation.
460
+ """
461
+
462
+ # initial condition
463
+ self.y0 = y0
464
+ # the point for initial conditions, default is zero.
465
+ self.x0 = x0
466
+ # differential operator L such that L.f = 0
467
+ self.annihilator = annihilator
468
+ self.x = x
469
+
470
+ def __str__(self):
471
+ if self._have_init_cond():
472
+ str_sol = 'HolonomicFunction(%s, %s, %s, %s)' % (str(self.annihilator),\
473
+ sstr(self.x), sstr(self.x0), sstr(self.y0))
474
+ else:
475
+ str_sol = 'HolonomicFunction(%s, %s)' % (str(self.annihilator),\
476
+ sstr(self.x))
477
+
478
+ return str_sol
479
+
480
+ __repr__ = __str__
481
+
482
+ def unify(self, other):
483
+ """
484
+ Unifies the base polynomial ring of a given two Holonomic
485
+ Functions.
486
+ """
487
+
488
+ R1 = self.annihilator.parent.base
489
+ R2 = other.annihilator.parent.base
490
+
491
+ dom1 = R1.dom
492
+ dom2 = R2.dom
493
+
494
+ if R1 == R2:
495
+ return (self, other)
496
+
497
+ R = (dom1.unify(dom2)).old_poly_ring(self.x)
498
+
499
+ newparent, _ = DifferentialOperators(R, str(self.annihilator.parent.gen_symbol))
500
+
501
+ sol1 = [R1.to_sympy(i) for i in self.annihilator.listofpoly]
502
+ sol2 = [R2.to_sympy(i) for i in other.annihilator.listofpoly]
503
+
504
+ sol1 = DifferentialOperator(sol1, newparent)
505
+ sol2 = DifferentialOperator(sol2, newparent)
506
+
507
+ sol1 = HolonomicFunction(sol1, self.x, self.x0, self.y0)
508
+ sol2 = HolonomicFunction(sol2, other.x, other.x0, other.y0)
509
+
510
+ return (sol1, sol2)
511
+
512
+ def is_singularics(self):
513
+ """
514
+ Returns True if the function have singular initial condition
515
+ in the dictionary format.
516
+
517
+ Returns False if the function have ordinary initial condition
518
+ in the list format.
519
+
520
+ Returns None for all other cases.
521
+ """
522
+
523
+ if isinstance(self.y0, dict):
524
+ return True
525
+ elif isinstance(self.y0, list):
526
+ return False
527
+
528
+ def _have_init_cond(self):
529
+ """
530
+ Checks if the function have initial condition.
531
+ """
532
+ return bool(self.y0)
533
+
534
+ def _singularics_to_ord(self):
535
+ """
536
+ Converts a singular initial condition to ordinary if possible.
537
+ """
538
+ a = list(self.y0)[0]
539
+ b = self.y0[a]
540
+
541
+ if len(self.y0) == 1 and a == int(a) and a > 0:
542
+ a = int(a)
543
+ y0 = [S.Zero] * a
544
+ y0 += [j * factorial(a + i) for i, j in enumerate(b)]
545
+
546
+ return HolonomicFunction(self.annihilator, self.x, self.x0, y0)
547
+
548
+ def __add__(self, other):
549
+ # if the ground domains are different
550
+ if self.annihilator.parent.base != other.annihilator.parent.base:
551
+ a, b = self.unify(other)
552
+ return a + b
553
+
554
+ deg1 = self.annihilator.order
555
+ deg2 = other.annihilator.order
556
+ dim = max(deg1, deg2)
557
+ R = self.annihilator.parent.base
558
+ K = R.get_field()
559
+
560
+ rowsself = [self.annihilator]
561
+ rowsother = [other.annihilator]
562
+ gen = self.annihilator.parent.derivative_operator
563
+
564
+ # constructing annihilators up to order dim
565
+ for i in range(dim - deg1):
566
+ diff1 = (gen * rowsself[-1])
567
+ rowsself.append(diff1)
568
+
569
+ for i in range(dim - deg2):
570
+ diff2 = (gen * rowsother[-1])
571
+ rowsother.append(diff2)
572
+
573
+ row = rowsself + rowsother
574
+
575
+ # constructing the matrix of the ansatz
576
+ r = []
577
+
578
+ for expr in row:
579
+ p = []
580
+ for i in range(dim + 1):
581
+ if i >= len(expr.listofpoly):
582
+ p.append(K.zero)
583
+ else:
584
+ p.append(K.new(expr.listofpoly[i].to_list()))
585
+ r.append(p)
586
+
587
+ # solving the linear system using gauss jordan solver
588
+ r = DomainMatrix(r, (len(row), dim+1), K).transpose()
589
+ homosys = DomainMatrix.zeros((dim+1, 1), K)
590
+ sol = _find_nonzero_solution(r, homosys)
591
+
592
+ # if a solution is not obtained then increasing the order by 1 in each
593
+ # iteration
594
+ while sol.is_zero_matrix:
595
+ dim += 1
596
+
597
+ diff1 = (gen * rowsself[-1])
598
+ rowsself.append(diff1)
599
+
600
+ diff2 = (gen * rowsother[-1])
601
+ rowsother.append(diff2)
602
+
603
+ row = rowsself + rowsother
604
+ r = []
605
+
606
+ for expr in row:
607
+ p = []
608
+ for i in range(dim + 1):
609
+ if i >= len(expr.listofpoly):
610
+ p.append(K.zero)
611
+ else:
612
+ p.append(K.new(expr.listofpoly[i].to_list()))
613
+ r.append(p)
614
+
615
+ # solving the linear system using gauss jordan solver
616
+ r = DomainMatrix(r, (len(row), dim+1), K).transpose()
617
+ homosys = DomainMatrix.zeros((dim+1, 1), K)
618
+ sol = _find_nonzero_solution(r, homosys)
619
+
620
+ # taking only the coefficients needed to multiply with `self`
621
+ # can be also be done the other way by taking R.H.S and multiplying with
622
+ # `other`
623
+ sol = sol.flat()[:dim + 1 - deg1]
624
+ sol1 = _normalize(sol, self.annihilator.parent)
625
+ # annihilator of the solution
626
+ sol = sol1 * (self.annihilator)
627
+ sol = _normalize(sol.listofpoly, self.annihilator.parent, negative=False)
628
+
629
+ if not (self._have_init_cond() and other._have_init_cond()):
630
+ return HolonomicFunction(sol, self.x)
631
+
632
+ # both the functions have ordinary initial conditions
633
+ if self.is_singularics() == False and other.is_singularics() == False:
634
+
635
+ # directly add the corresponding value
636
+ if self.x0 == other.x0:
637
+ # try to extended the initial conditions
638
+ # using the annihilator
639
+ y1 = _extend_y0(self, sol.order)
640
+ y2 = _extend_y0(other, sol.order)
641
+ y0 = [a + b for a, b in zip(y1, y2)]
642
+ return HolonomicFunction(sol, self.x, self.x0, y0)
643
+
644
+ # change the initial conditions to a same point
645
+ selfat0 = self.annihilator.is_singular(0)
646
+ otherat0 = other.annihilator.is_singular(0)
647
+ if self.x0 == 0 and not selfat0 and not otherat0:
648
+ return self + other.change_ics(0)
649
+ if other.x0 == 0 and not selfat0 and not otherat0:
650
+ return self.change_ics(0) + other
651
+
652
+ selfatx0 = self.annihilator.is_singular(self.x0)
653
+ otheratx0 = other.annihilator.is_singular(self.x0)
654
+ if not selfatx0 and not otheratx0:
655
+ return self + other.change_ics(self.x0)
656
+ return self.change_ics(other.x0) + other
657
+
658
+ if self.x0 != other.x0:
659
+ return HolonomicFunction(sol, self.x)
660
+
661
+ # if the functions have singular_ics
662
+ y1 = None
663
+ y2 = None
664
+
665
+ if self.is_singularics() == False and other.is_singularics() == True:
666
+ # convert the ordinary initial condition to singular.
667
+ _y0 = [j / factorial(i) for i, j in enumerate(self.y0)]
668
+ y1 = {S.Zero: _y0}
669
+ y2 = other.y0
670
+ elif self.is_singularics() == True and other.is_singularics() == False:
671
+ _y0 = [j / factorial(i) for i, j in enumerate(other.y0)]
672
+ y1 = self.y0
673
+ y2 = {S.Zero: _y0}
674
+ elif self.is_singularics() == True and other.is_singularics() == True:
675
+ y1 = self.y0
676
+ y2 = other.y0
677
+
678
+ # computing singular initial condition for the result
679
+ # taking union of the series terms of both functions
680
+ y0 = {}
681
+ for i in y1:
682
+ # add corresponding initial terms if the power
683
+ # on `x` is same
684
+ if i in y2:
685
+ y0[i] = [a + b for a, b in zip(y1[i], y2[i])]
686
+ else:
687
+ y0[i] = y1[i]
688
+ for i in y2:
689
+ if i not in y1:
690
+ y0[i] = y2[i]
691
+ return HolonomicFunction(sol, self.x, self.x0, y0)
692
+
693
+ def integrate(self, limits, initcond=False):
694
+ """
695
+ Integrates the given holonomic function.
696
+
697
+ Examples
698
+ ========
699
+
700
+ >>> from sympy.holonomic.holonomic import HolonomicFunction, DifferentialOperators
701
+ >>> from sympy import QQ
702
+ >>> from sympy import symbols
703
+ >>> x = symbols('x')
704
+ >>> R, Dx = DifferentialOperators(QQ.old_poly_ring(x),'Dx')
705
+ >>> HolonomicFunction(Dx - 1, x, 0, [1]).integrate((x, 0, x)) # e^x - 1
706
+ HolonomicFunction((-1)*Dx + (1)*Dx**2, x, 0, [0, 1])
707
+ >>> HolonomicFunction(Dx**2 + 1, x, 0, [1, 0]).integrate((x, 0, x))
708
+ HolonomicFunction((1)*Dx + (1)*Dx**3, x, 0, [0, 1, 0])
709
+ """
710
+
711
+ # to get the annihilator, just multiply by Dx from right
712
+ D = self.annihilator.parent.derivative_operator
713
+
714
+ # if the function have initial conditions of the series format
715
+ if self.is_singularics() == True:
716
+
717
+ r = self._singularics_to_ord()
718
+ if r:
719
+ return r.integrate(limits, initcond=initcond)
720
+
721
+ # computing singular initial condition for the function
722
+ # produced after integration.
723
+ y0 = {}
724
+ for i in self.y0:
725
+ c = self.y0[i]
726
+ c2 = []
727
+ for j, cj in enumerate(c):
728
+ if cj == 0:
729
+ c2.append(S.Zero)
730
+
731
+ # if power on `x` is -1, the integration becomes log(x)
732
+ # TODO: Implement this case
733
+ elif i + j + 1 == 0:
734
+ raise NotImplementedError("logarithmic terms in the series are not supported")
735
+ else:
736
+ c2.append(cj / S(i + j + 1))
737
+ y0[i + 1] = c2
738
+
739
+ if hasattr(limits, "__iter__"):
740
+ raise NotImplementedError("Definite integration for singular initial conditions")
741
+
742
+ return HolonomicFunction(self.annihilator * D, self.x, self.x0, y0)
743
+
744
+ # if no initial conditions are available for the function
745
+ if not self._have_init_cond():
746
+ if initcond:
747
+ return HolonomicFunction(self.annihilator * D, self.x, self.x0, [S.Zero])
748
+ return HolonomicFunction(self.annihilator * D, self.x)
749
+
750
+ # definite integral
751
+ # initial conditions for the answer will be stored at point `a`,
752
+ # where `a` is the lower limit of the integrand
753
+ if hasattr(limits, "__iter__"):
754
+
755
+ if len(limits) == 3 and limits[0] == self.x:
756
+ x0 = self.x0
757
+ a = limits[1]
758
+ b = limits[2]
759
+ definite = True
760
+
761
+ else:
762
+ definite = False
763
+
764
+ y0 = [S.Zero]
765
+ y0 += self.y0
766
+
767
+ indefinite_integral = HolonomicFunction(self.annihilator * D, self.x, self.x0, y0)
768
+
769
+ if not definite:
770
+ return indefinite_integral
771
+
772
+ # use evalf to get the values at `a`
773
+ if x0 != a:
774
+ try:
775
+ indefinite_expr = indefinite_integral.to_expr()
776
+ except (NotHyperSeriesError, NotPowerSeriesError):
777
+ indefinite_expr = None
778
+
779
+ if indefinite_expr:
780
+ lower = indefinite_expr.subs(self.x, a)
781
+ if isinstance(lower, NaN):
782
+ lower = indefinite_expr.limit(self.x, a)
783
+ else:
784
+ lower = indefinite_integral.evalf(a)
785
+
786
+ if b == self.x:
787
+ y0[0] = y0[0] - lower
788
+ return HolonomicFunction(self.annihilator * D, self.x, x0, y0)
789
+
790
+ elif S(b).is_Number:
791
+ if indefinite_expr:
792
+ upper = indefinite_expr.subs(self.x, b)
793
+ if isinstance(upper, NaN):
794
+ upper = indefinite_expr.limit(self.x, b)
795
+ else:
796
+ upper = indefinite_integral.evalf(b)
797
+
798
+ return upper - lower
799
+
800
+
801
+ # if the upper limit is `x`, the answer will be a function
802
+ if b == self.x:
803
+ return HolonomicFunction(self.annihilator * D, self.x, a, y0)
804
+
805
+ # if the upper limits is a Number, a numerical value will be returned
806
+ elif S(b).is_Number:
807
+ try:
808
+ s = HolonomicFunction(self.annihilator * D, self.x, a,\
809
+ y0).to_expr()
810
+ indefinite = s.subs(self.x, b)
811
+ if not isinstance(indefinite, NaN):
812
+ return indefinite
813
+ else:
814
+ return s.limit(self.x, b)
815
+ except (NotHyperSeriesError, NotPowerSeriesError):
816
+ return HolonomicFunction(self.annihilator * D, self.x, a, y0).evalf(b)
817
+
818
+ return HolonomicFunction(self.annihilator * D, self.x)
819
+
820
+ def diff(self, *args, **kwargs):
821
+ r"""
822
+ Differentiation of the given Holonomic function.
823
+
824
+ Examples
825
+ ========
826
+
827
+ >>> from sympy.holonomic.holonomic import HolonomicFunction, DifferentialOperators
828
+ >>> from sympy import ZZ
829
+ >>> from sympy import symbols
830
+ >>> x = symbols('x')
831
+ >>> R, Dx = DifferentialOperators(ZZ.old_poly_ring(x),'Dx')
832
+ >>> HolonomicFunction(Dx**2 + 1, x, 0, [0, 1]).diff().to_expr()
833
+ cos(x)
834
+ >>> HolonomicFunction(Dx - 2, x, 0, [1]).diff().to_expr()
835
+ 2*exp(2*x)
836
+
837
+ See Also
838
+ ========
839
+
840
+ integrate
841
+ """
842
+ kwargs.setdefault('evaluate', True)
843
+ if args:
844
+ if args[0] != self.x:
845
+ return S.Zero
846
+ elif len(args) == 2:
847
+ sol = self
848
+ for i in range(args[1]):
849
+ sol = sol.diff(args[0])
850
+ return sol
851
+
852
+ ann = self.annihilator
853
+
854
+ # if the function is constant.
855
+ if ann.listofpoly[0] == ann.parent.base.zero and ann.order == 1:
856
+ return S.Zero
857
+
858
+ # if the coefficient of y in the differential equation is zero.
859
+ # a shifting is done to compute the answer in this case.
860
+ elif ann.listofpoly[0] == ann.parent.base.zero:
861
+
862
+ sol = DifferentialOperator(ann.listofpoly[1:], ann.parent)
863
+
864
+ if self._have_init_cond():
865
+ # if ordinary initial condition
866
+ if self.is_singularics() == False:
867
+ return HolonomicFunction(sol, self.x, self.x0, self.y0[1:])
868
+ # TODO: support for singular initial condition
869
+ return HolonomicFunction(sol, self.x)
870
+ else:
871
+ return HolonomicFunction(sol, self.x)
872
+
873
+ # the general algorithm
874
+ R = ann.parent.base
875
+ K = R.get_field()
876
+
877
+ seq_dmf = [K.new(i.to_list()) for i in ann.listofpoly]
878
+
879
+ # -y = a1*y'/a0 + a2*y''/a0 ... + an*y^n/a0
880
+ rhs = [i / seq_dmf[0] for i in seq_dmf[1:]]
881
+ rhs.insert(0, K.zero)
882
+
883
+ # differentiate both lhs and rhs
884
+ sol = _derivate_diff_eq(rhs, K)
885
+
886
+ # add the term y' in lhs to rhs
887
+ sol = _add_lists(sol, [K.zero, K.one])
888
+
889
+ sol = _normalize(sol[1:], self.annihilator.parent, negative=False)
890
+
891
+ if not self._have_init_cond() or self.is_singularics() == True:
892
+ return HolonomicFunction(sol, self.x)
893
+
894
+ y0 = _extend_y0(self, sol.order + 1)[1:]
895
+ return HolonomicFunction(sol, self.x, self.x0, y0)
896
+
897
+ def __eq__(self, other):
898
+ if self.annihilator != other.annihilator or self.x != other.x:
899
+ return False
900
+ if self._have_init_cond() and other._have_init_cond():
901
+ return self.x0 == other.x0 and self.y0 == other.y0
902
+ return True
903
+
904
+ def __mul__(self, other):
905
+ ann_self = self.annihilator
906
+
907
+ if not isinstance(other, HolonomicFunction):
908
+ other = sympify(other)
909
+
910
+ if other.has(self.x):
911
+ raise NotImplementedError(" Can't multiply a HolonomicFunction and expressions/functions.")
912
+
913
+ if not self._have_init_cond():
914
+ return self
915
+ y0 = _extend_y0(self, ann_self.order)
916
+ y1 = [(Poly.new(j, self.x) * other).rep for j in y0]
917
+ return HolonomicFunction(ann_self, self.x, self.x0, y1)
918
+
919
+ if self.annihilator.parent.base != other.annihilator.parent.base:
920
+ a, b = self.unify(other)
921
+ return a * b
922
+
923
+ ann_other = other.annihilator
924
+
925
+ a = ann_self.order
926
+ b = ann_other.order
927
+
928
+ R = ann_self.parent.base
929
+ K = R.get_field()
930
+
931
+ list_self = [K.new(j.to_list()) for j in ann_self.listofpoly]
932
+ list_other = [K.new(j.to_list()) for j in ann_other.listofpoly]
933
+
934
+ # will be used to reduce the degree
935
+ self_red = [-list_self[i] / list_self[a] for i in range(a)]
936
+
937
+ other_red = [-list_other[i] / list_other[b] for i in range(b)]
938
+
939
+ # coeff_mull[i][j] is the coefficient of Dx^i(f).Dx^j(g)
940
+ coeff_mul = [[K.zero for i in range(b + 1)] for j in range(a + 1)]
941
+ coeff_mul[0][0] = K.one
942
+
943
+ # making the ansatz
944
+ lin_sys_elements = [[coeff_mul[i][j] for i in range(a) for j in range(b)]]
945
+ lin_sys = DomainMatrix(lin_sys_elements, (1, a*b), K).transpose()
946
+
947
+ homo_sys = DomainMatrix.zeros((a*b, 1), K)
948
+
949
+ sol = _find_nonzero_solution(lin_sys, homo_sys)
950
+
951
+ # until a non trivial solution is found
952
+ while sol.is_zero_matrix:
953
+
954
+ # updating the coefficients Dx^i(f).Dx^j(g) for next degree
955
+ for i in range(a - 1, -1, -1):
956
+ for j in range(b - 1, -1, -1):
957
+ coeff_mul[i][j + 1] += coeff_mul[i][j]
958
+ coeff_mul[i + 1][j] += coeff_mul[i][j]
959
+ if isinstance(coeff_mul[i][j], K.dtype):
960
+ coeff_mul[i][j] = DMFdiff(coeff_mul[i][j], K)
961
+ else:
962
+ coeff_mul[i][j] = coeff_mul[i][j].diff(self.x)
963
+
964
+ # reduce the terms to lower power using annihilators of f, g
965
+ for i in range(a + 1):
966
+ if coeff_mul[i][b].is_zero:
967
+ continue
968
+ for j in range(b):
969
+ coeff_mul[i][j] += other_red[j] * coeff_mul[i][b]
970
+ coeff_mul[i][b] = K.zero
971
+
972
+ # not d2 + 1, as that is already covered in previous loop
973
+ for j in range(b):
974
+ if coeff_mul[a][j] == 0:
975
+ continue
976
+ for i in range(a):
977
+ coeff_mul[i][j] += self_red[i] * coeff_mul[a][j]
978
+ coeff_mul[a][j] = K.zero
979
+
980
+ lin_sys_elements.append([coeff_mul[i][j] for i in range(a) for j in range(b)])
981
+ lin_sys = DomainMatrix(lin_sys_elements, (len(lin_sys_elements), a*b), K).transpose()
982
+
983
+ sol = _find_nonzero_solution(lin_sys, homo_sys)
984
+
985
+ sol_ann = _normalize(sol.flat(), self.annihilator.parent, negative=False)
986
+
987
+ if not (self._have_init_cond() and other._have_init_cond()):
988
+ return HolonomicFunction(sol_ann, self.x)
989
+
990
+ if self.is_singularics() == False and other.is_singularics() == False:
991
+
992
+ # if both the conditions are at same point
993
+ if self.x0 == other.x0:
994
+
995
+ # try to find more initial conditions
996
+ y0_self = _extend_y0(self, sol_ann.order)
997
+ y0_other = _extend_y0(other, sol_ann.order)
998
+ # h(x0) = f(x0) * g(x0)
999
+ y0 = [y0_self[0] * y0_other[0]]
1000
+
1001
+ # coefficient of Dx^j(f)*Dx^i(g) in Dx^i(fg)
1002
+ for i in range(1, min(len(y0_self), len(y0_other))):
1003
+ coeff = [[0 for i in range(i + 1)] for j in range(i + 1)]
1004
+ for j in range(i + 1):
1005
+ for k in range(i + 1):
1006
+ if j + k == i:
1007
+ coeff[j][k] = binomial(i, j)
1008
+
1009
+ sol = 0
1010
+ for j in range(i + 1):
1011
+ for k in range(i + 1):
1012
+ sol += coeff[j][k]* y0_self[j] * y0_other[k]
1013
+
1014
+ y0.append(sol)
1015
+
1016
+ return HolonomicFunction(sol_ann, self.x, self.x0, y0)
1017
+
1018
+ # if the points are different, consider one
1019
+ selfat0 = self.annihilator.is_singular(0)
1020
+ otherat0 = other.annihilator.is_singular(0)
1021
+
1022
+ if self.x0 == 0 and not selfat0 and not otherat0:
1023
+ return self * other.change_ics(0)
1024
+ if other.x0 == 0 and not selfat0 and not otherat0:
1025
+ return self.change_ics(0) * other
1026
+
1027
+ selfatx0 = self.annihilator.is_singular(self.x0)
1028
+ otheratx0 = other.annihilator.is_singular(self.x0)
1029
+ if not selfatx0 and not otheratx0:
1030
+ return self * other.change_ics(self.x0)
1031
+ return self.change_ics(other.x0) * other
1032
+
1033
+ if self.x0 != other.x0:
1034
+ return HolonomicFunction(sol_ann, self.x)
1035
+
1036
+ # if the functions have singular_ics
1037
+ y1 = None
1038
+ y2 = None
1039
+
1040
+ if self.is_singularics() == False and other.is_singularics() == True:
1041
+ _y0 = [j / factorial(i) for i, j in enumerate(self.y0)]
1042
+ y1 = {S.Zero: _y0}
1043
+ y2 = other.y0
1044
+ elif self.is_singularics() == True and other.is_singularics() == False:
1045
+ _y0 = [j / factorial(i) for i, j in enumerate(other.y0)]
1046
+ y1 = self.y0
1047
+ y2 = {S.Zero: _y0}
1048
+ elif self.is_singularics() == True and other.is_singularics() == True:
1049
+ y1 = self.y0
1050
+ y2 = other.y0
1051
+
1052
+ y0 = {}
1053
+ # multiply every possible pair of the series terms
1054
+ for i in y1:
1055
+ for j in y2:
1056
+ k = min(len(y1[i]), len(y2[j]))
1057
+ c = [sum((y1[i][b] * y2[j][a - b] for b in range(a + 1)),
1058
+ start=S.Zero) for a in range(k)]
1059
+ if not i + j in y0:
1060
+ y0[i + j] = c
1061
+ else:
1062
+ y0[i + j] = [a + b for a, b in zip(c, y0[i + j])]
1063
+ return HolonomicFunction(sol_ann, self.x, self.x0, y0)
1064
+
1065
+ __rmul__ = __mul__
1066
+
1067
+ def __sub__(self, other):
1068
+ return self + other * -1
1069
+
1070
+ def __rsub__(self, other):
1071
+ return self * -1 + other
1072
+
1073
+ def __neg__(self):
1074
+ return -1 * self
1075
+
1076
+ def __truediv__(self, other):
1077
+ return self * (S.One / other)
1078
+
1079
+ def __pow__(self, n):
1080
+ if self.annihilator.order <= 1:
1081
+ ann = self.annihilator
1082
+ parent = ann.parent
1083
+
1084
+ if self.y0 is None:
1085
+ y0 = None
1086
+ else:
1087
+ y0 = [list(self.y0)[0] ** n]
1088
+
1089
+ p0 = ann.listofpoly[0]
1090
+ p1 = ann.listofpoly[1]
1091
+
1092
+ p0 = (Poly.new(p0, self.x) * n).rep
1093
+
1094
+ sol = [parent.base.to_sympy(i) for i in [p0, p1]]
1095
+ dd = DifferentialOperator(sol, parent)
1096
+ return HolonomicFunction(dd, self.x, self.x0, y0)
1097
+ if n < 0:
1098
+ raise NotHolonomicError("Negative Power on a Holonomic Function")
1099
+ Dx = self.annihilator.parent.derivative_operator
1100
+ result = HolonomicFunction(Dx, self.x, S.Zero, [S.One])
1101
+ if n == 0:
1102
+ return result
1103
+ x = self
1104
+ while True:
1105
+ if n % 2:
1106
+ result *= x
1107
+ n >>= 1
1108
+ if not n:
1109
+ break
1110
+ x *= x
1111
+ return result
1112
+
1113
+ def degree(self):
1114
+ """
1115
+ Returns the highest power of `x` in the annihilator.
1116
+ """
1117
+ return max(i.degree() for i in self.annihilator.listofpoly)
1118
+
1119
+ def composition(self, expr, *args, **kwargs):
1120
+ """
1121
+ Returns function after composition of a holonomic
1122
+ function with an algebraic function. The method cannot compute
1123
+ initial conditions for the result by itself, so they can be also be
1124
+ provided.
1125
+
1126
+ Examples
1127
+ ========
1128
+
1129
+ >>> from sympy.holonomic.holonomic import HolonomicFunction, DifferentialOperators
1130
+ >>> from sympy import QQ
1131
+ >>> from sympy import symbols
1132
+ >>> x = symbols('x')
1133
+ >>> R, Dx = DifferentialOperators(QQ.old_poly_ring(x),'Dx')
1134
+ >>> HolonomicFunction(Dx - 1, x).composition(x**2, 0, [1]) # e^(x**2)
1135
+ HolonomicFunction((-2*x) + (1)*Dx, x, 0, [1])
1136
+ >>> HolonomicFunction(Dx**2 + 1, x).composition(x**2 - 1, 1, [1, 0])
1137
+ HolonomicFunction((4*x**3) + (-1)*Dx + (x)*Dx**2, x, 1, [1, 0])
1138
+
1139
+ See Also
1140
+ ========
1141
+
1142
+ from_hyper
1143
+ """
1144
+
1145
+ R = self.annihilator.parent
1146
+ a = self.annihilator.order
1147
+ diff = expr.diff(self.x)
1148
+ listofpoly = self.annihilator.listofpoly
1149
+
1150
+ for i, j in enumerate(listofpoly):
1151
+ if isinstance(j, self.annihilator.parent.base.dtype):
1152
+ listofpoly[i] = self.annihilator.parent.base.to_sympy(j)
1153
+
1154
+ r = listofpoly[a].subs({self.x:expr})
1155
+ subs = [-listofpoly[i].subs({self.x:expr}) / r for i in range (a)]
1156
+ coeffs = [S.Zero for i in range(a)] # coeffs[i] == coeff of (D^i f)(a) in D^k (f(a))
1157
+ coeffs[0] = S.One
1158
+ system = [coeffs]
1159
+ homogeneous = Matrix([[S.Zero for i in range(a)]]).transpose()
1160
+ while True:
1161
+ coeffs_next = [p.diff(self.x) for p in coeffs]
1162
+ for i in range(a - 1):
1163
+ coeffs_next[i + 1] += (coeffs[i] * diff)
1164
+ for i in range(a):
1165
+ coeffs_next[i] += (coeffs[-1] * subs[i] * diff)
1166
+ coeffs = coeffs_next
1167
+ # check for linear relations
1168
+ system.append(coeffs)
1169
+ sol, taus = (Matrix(system).transpose()
1170
+ ).gauss_jordan_solve(homogeneous)
1171
+ if sol.is_zero_matrix is not True:
1172
+ break
1173
+
1174
+ tau = list(taus)[0]
1175
+ sol = sol.subs(tau, 1)
1176
+ sol = _normalize(sol[0:], R, negative=False)
1177
+
1178
+ # if initial conditions are given for the resulting function
1179
+ if args:
1180
+ return HolonomicFunction(sol, self.x, args[0], args[1])
1181
+ return HolonomicFunction(sol, self.x)
1182
+
1183
+ def to_sequence(self, lb=True):
1184
+ r"""
1185
+ Finds recurrence relation for the coefficients in the series expansion
1186
+ of the function about :math:`x_0`, where :math:`x_0` is the point at
1187
+ which the initial condition is stored.
1188
+
1189
+ Explanation
1190
+ ===========
1191
+
1192
+ If the point :math:`x_0` is ordinary, solution of the form :math:`[(R, n_0)]`
1193
+ is returned. Where :math:`R` is the recurrence relation and :math:`n_0` is the
1194
+ smallest ``n`` for which the recurrence holds true.
1195
+
1196
+ If the point :math:`x_0` is regular singular, a list of solutions in
1197
+ the format :math:`(R, p, n_0)` is returned, i.e. `[(R, p, n_0), ... ]`.
1198
+ Each tuple in this vector represents a recurrence relation :math:`R`
1199
+ associated with a root of the indicial equation ``p``. Conditions of
1200
+ a different format can also be provided in this case, see the
1201
+ docstring of HolonomicFunction class.
1202
+
1203
+ If it's not possible to numerically compute a initial condition,
1204
+ it is returned as a symbol :math:`C_j`, denoting the coefficient of
1205
+ :math:`(x - x_0)^j` in the power series about :math:`x_0`.
1206
+
1207
+ Examples
1208
+ ========
1209
+
1210
+ >>> from sympy.holonomic.holonomic import HolonomicFunction, DifferentialOperators
1211
+ >>> from sympy import QQ
1212
+ >>> from sympy import symbols, S
1213
+ >>> x = symbols('x')
1214
+ >>> R, Dx = DifferentialOperators(QQ.old_poly_ring(x),'Dx')
1215
+ >>> HolonomicFunction(Dx - 1, x, 0, [1]).to_sequence()
1216
+ [(HolonomicSequence((-1) + (n + 1)Sn, n), u(0) = 1, 0)]
1217
+ >>> HolonomicFunction((1 + x)*Dx**2 + Dx, x, 0, [0, 1]).to_sequence()
1218
+ [(HolonomicSequence((n**2) + (n**2 + n)Sn, n), u(0) = 0, u(1) = 1, u(2) = -1/2, 2)]
1219
+ >>> HolonomicFunction(-S(1)/2 + x*Dx, x, 0, {S(1)/2: [1]}).to_sequence()
1220
+ [(HolonomicSequence((n), n), u(0) = 1, 1/2, 1)]
1221
+
1222
+ See Also
1223
+ ========
1224
+
1225
+ HolonomicFunction.series
1226
+
1227
+ References
1228
+ ==========
1229
+
1230
+ .. [1] https://hal.inria.fr/inria-00070025/document
1231
+ .. [2] https://www3.risc.jku.at/publications/download/risc_2244/DIPLFORM.pdf
1232
+
1233
+ """
1234
+
1235
+ if self.x0 != 0:
1236
+ return self.shift_x(self.x0).to_sequence()
1237
+
1238
+ # check whether a power series exists if the point is singular
1239
+ if self.annihilator.is_singular(self.x0):
1240
+ return self._frobenius(lb=lb)
1241
+
1242
+ dict1 = {}
1243
+ n = Symbol('n', integer=True)
1244
+ dom = self.annihilator.parent.base.dom
1245
+ R, _ = RecurrenceOperators(dom.old_poly_ring(n), 'Sn')
1246
+
1247
+ # substituting each term of the form `x^k Dx^j` in the
1248
+ # annihilator, according to the formula below:
1249
+ # x^k Dx^j = Sum(rf(n + 1 - k, j) * a(n + j - k) * x^n, (n, k, oo))
1250
+ # for explanation see [2].
1251
+ for i, j in enumerate(self.annihilator.listofpoly):
1252
+
1253
+ listofdmp = j.all_coeffs()
1254
+ degree = len(listofdmp) - 1
1255
+
1256
+ for k in range(degree + 1):
1257
+ coeff = listofdmp[degree - k]
1258
+
1259
+ if coeff == 0:
1260
+ continue
1261
+
1262
+ if (i - k, k) in dict1:
1263
+ dict1[(i - k, k)] += (dom.to_sympy(coeff) * rf(n - k + 1, i))
1264
+ else:
1265
+ dict1[(i - k, k)] = (dom.to_sympy(coeff) * rf(n - k + 1, i))
1266
+
1267
+
1268
+ sol = []
1269
+ keylist = [i[0] for i in dict1]
1270
+ lower = min(keylist)
1271
+ upper = max(keylist)
1272
+ degree = self.degree()
1273
+
1274
+ # the recurrence relation holds for all values of
1275
+ # n greater than smallest_n, i.e. n >= smallest_n
1276
+ smallest_n = lower + degree
1277
+ dummys = {}
1278
+ eqs = []
1279
+ unknowns = []
1280
+
1281
+ # an appropriate shift of the recurrence
1282
+ for j in range(lower, upper + 1):
1283
+ if j in keylist:
1284
+ temp = sum((v.subs(n, n - lower)
1285
+ for k, v in dict1.items() if k[0] == j),
1286
+ start=S.Zero)
1287
+ sol.append(temp)
1288
+ else:
1289
+ sol.append(S.Zero)
1290
+
1291
+ # the recurrence relation
1292
+ sol = RecurrenceOperator(sol, R)
1293
+
1294
+ # computing the initial conditions for recurrence
1295
+ order = sol.order
1296
+ all_roots = roots(R.base.to_sympy(sol.listofpoly[-1]), n, filter='Z')
1297
+ all_roots = all_roots.keys()
1298
+
1299
+ if all_roots:
1300
+ max_root = max(all_roots) + 1
1301
+ smallest_n = max(max_root, smallest_n)
1302
+ order += smallest_n
1303
+
1304
+ y0 = _extend_y0(self, order)
1305
+ # u(n) = y^n(0)/factorial(n)
1306
+ u0 = [j / factorial(i) for i, j in enumerate(y0)]
1307
+
1308
+ # if sufficient conditions can't be computed then
1309
+ # try to use the series method i.e.
1310
+ # equate the coefficients of x^k in the equation formed by
1311
+ # substituting the series in differential equation, to zero.
1312
+ if len(u0) < order:
1313
+
1314
+ for i in range(degree):
1315
+ eq = S.Zero
1316
+
1317
+ for j in dict1:
1318
+
1319
+ if i + j[0] < 0:
1320
+ dummys[i + j[0]] = S.Zero
1321
+
1322
+ elif i + j[0] < len(u0):
1323
+ dummys[i + j[0]] = u0[i + j[0]]
1324
+
1325
+ elif not i + j[0] in dummys:
1326
+ dummys[i + j[0]] = Symbol('C_%s' %(i + j[0]))
1327
+ unknowns.append(dummys[i + j[0]])
1328
+
1329
+ if j[1] <= i:
1330
+ eq += dict1[j].subs(n, i) * dummys[i + j[0]]
1331
+
1332
+ eqs.append(eq)
1333
+
1334
+ # solve the system of equations formed
1335
+ soleqs = solve(eqs, *unknowns)
1336
+
1337
+ if isinstance(soleqs, dict):
1338
+
1339
+ for i in range(len(u0), order):
1340
+
1341
+ if i not in dummys:
1342
+ dummys[i] = Symbol('C_%s' %i)
1343
+
1344
+ if dummys[i] in soleqs:
1345
+ u0.append(soleqs[dummys[i]])
1346
+
1347
+ else:
1348
+ u0.append(dummys[i])
1349
+
1350
+ if lb:
1351
+ return [(HolonomicSequence(sol, u0), smallest_n)]
1352
+ return [HolonomicSequence(sol, u0)]
1353
+
1354
+ for i in range(len(u0), order):
1355
+
1356
+ if i not in dummys:
1357
+ dummys[i] = Symbol('C_%s' %i)
1358
+
1359
+ s = False
1360
+ for j in soleqs:
1361
+ if dummys[i] in j:
1362
+ u0.append(j[dummys[i]])
1363
+ s = True
1364
+ if not s:
1365
+ u0.append(dummys[i])
1366
+
1367
+ if lb:
1368
+ return [(HolonomicSequence(sol, u0), smallest_n)]
1369
+
1370
+ return [HolonomicSequence(sol, u0)]
1371
+
1372
+ def _frobenius(self, lb=True):
1373
+ # compute the roots of indicial equation
1374
+ indicialroots = self._indicial()
1375
+
1376
+ reals = []
1377
+ compl = []
1378
+ for i in ordered(indicialroots.keys()):
1379
+ if i.is_real:
1380
+ reals.extend([i] * indicialroots[i])
1381
+ else:
1382
+ a, b = i.as_real_imag()
1383
+ compl.extend([(i, a, b)] * indicialroots[i])
1384
+
1385
+ # sort the roots for a fixed ordering of solution
1386
+ compl.sort(key=lambda x : x[1])
1387
+ compl.sort(key=lambda x : x[2])
1388
+ reals.sort()
1389
+
1390
+ # grouping the roots, roots differ by an integer are put in the same group.
1391
+ grp = []
1392
+
1393
+ for i in reals:
1394
+ if len(grp) == 0:
1395
+ grp.append([i])
1396
+ continue
1397
+ for j in grp:
1398
+ if int_valued(j[0] - i):
1399
+ j.append(i)
1400
+ break
1401
+ else:
1402
+ grp.append([i])
1403
+
1404
+ # True if none of the roots differ by an integer i.e.
1405
+ # each element in group have only one member
1406
+ independent = all(len(i) == 1 for i in grp)
1407
+
1408
+ allpos = all(i >= 0 for i in reals)
1409
+ allint = all(int_valued(i) for i in reals)
1410
+
1411
+ # if initial conditions are provided
1412
+ # then use them.
1413
+ if self.is_singularics() == True:
1414
+ rootstoconsider = []
1415
+ for i in ordered(self.y0.keys()):
1416
+ for j in ordered(indicialroots.keys()):
1417
+ if equal_valued(j, i):
1418
+ rootstoconsider.append(i)
1419
+
1420
+ elif allpos and allint:
1421
+ rootstoconsider = [min(reals)]
1422
+
1423
+ elif independent:
1424
+ rootstoconsider = [i[0] for i in grp] + [j[0] for j in compl]
1425
+
1426
+ elif not allint:
1427
+ rootstoconsider = [i for i in reals if not int(i) == i]
1428
+
1429
+ elif not allpos:
1430
+
1431
+ if not self._have_init_cond() or S(self.y0[0]).is_finite == False:
1432
+ rootstoconsider = [min(reals)]
1433
+
1434
+ else:
1435
+ posroots = [i for i in reals if i >= 0]
1436
+ rootstoconsider = [min(posroots)]
1437
+
1438
+ n = Symbol('n', integer=True)
1439
+ dom = self.annihilator.parent.base.dom
1440
+ R, _ = RecurrenceOperators(dom.old_poly_ring(n), 'Sn')
1441
+
1442
+ finalsol = []
1443
+ char = ord('C')
1444
+
1445
+ for p in rootstoconsider:
1446
+ dict1 = {}
1447
+
1448
+ for i, j in enumerate(self.annihilator.listofpoly):
1449
+
1450
+ listofdmp = j.all_coeffs()
1451
+ degree = len(listofdmp) - 1
1452
+
1453
+ for k in range(degree + 1):
1454
+ coeff = listofdmp[degree - k]
1455
+
1456
+ if coeff == 0:
1457
+ continue
1458
+
1459
+ if (i - k, k - i) in dict1:
1460
+ dict1[(i - k, k - i)] += (dom.to_sympy(coeff) * rf(n - k + 1 + p, i))
1461
+ else:
1462
+ dict1[(i - k, k - i)] = (dom.to_sympy(coeff) * rf(n - k + 1 + p, i))
1463
+
1464
+ sol = []
1465
+ keylist = [i[0] for i in dict1]
1466
+ lower = min(keylist)
1467
+ upper = max(keylist)
1468
+ degree = max(i[1] for i in dict1)
1469
+ degree2 = min(i[1] for i in dict1)
1470
+
1471
+ smallest_n = lower + degree
1472
+ dummys = {}
1473
+ eqs = []
1474
+ unknowns = []
1475
+
1476
+ for j in range(lower, upper + 1):
1477
+ if j in keylist:
1478
+ temp = sum((v.subs(n, n - lower)
1479
+ for k, v in dict1.items() if k[0] == j),
1480
+ start=S.Zero)
1481
+ sol.append(temp)
1482
+ else:
1483
+ sol.append(S.Zero)
1484
+
1485
+ # the recurrence relation
1486
+ sol = RecurrenceOperator(sol, R)
1487
+
1488
+ # computing the initial conditions for recurrence
1489
+ order = sol.order
1490
+ all_roots = roots(R.base.to_sympy(sol.listofpoly[-1]), n, filter='Z')
1491
+ all_roots = all_roots.keys()
1492
+
1493
+ if all_roots:
1494
+ max_root = max(all_roots) + 1
1495
+ smallest_n = max(max_root, smallest_n)
1496
+ order += smallest_n
1497
+
1498
+ u0 = []
1499
+
1500
+ if self.is_singularics() == True:
1501
+ u0 = self.y0[p]
1502
+
1503
+ elif self.is_singularics() == False and p >= 0 and int(p) == p and len(rootstoconsider) == 1:
1504
+ y0 = _extend_y0(self, order + int(p))
1505
+ # u(n) = y^n(0)/factorial(n)
1506
+ if len(y0) > int(p):
1507
+ u0 = [y0[i] / factorial(i) for i in range(int(p), len(y0))]
1508
+
1509
+ if len(u0) < order:
1510
+
1511
+ for i in range(degree2, degree):
1512
+ eq = S.Zero
1513
+
1514
+ for j in dict1:
1515
+ if i + j[0] < 0:
1516
+ dummys[i + j[0]] = S.Zero
1517
+
1518
+ elif i + j[0] < len(u0):
1519
+ dummys[i + j[0]] = u0[i + j[0]]
1520
+
1521
+ elif not i + j[0] in dummys:
1522
+ letter = chr(char) + '_%s' %(i + j[0])
1523
+ dummys[i + j[0]] = Symbol(letter)
1524
+ unknowns.append(dummys[i + j[0]])
1525
+
1526
+ if j[1] <= i:
1527
+ eq += dict1[j].subs(n, i) * dummys[i + j[0]]
1528
+
1529
+ eqs.append(eq)
1530
+
1531
+ # solve the system of equations formed
1532
+ soleqs = solve(eqs, *unknowns)
1533
+
1534
+ if isinstance(soleqs, dict):
1535
+
1536
+ for i in range(len(u0), order):
1537
+
1538
+ if i not in dummys:
1539
+ letter = chr(char) + '_%s' %i
1540
+ dummys[i] = Symbol(letter)
1541
+
1542
+ if dummys[i] in soleqs:
1543
+ u0.append(soleqs[dummys[i]])
1544
+
1545
+ else:
1546
+ u0.append(dummys[i])
1547
+
1548
+ if lb:
1549
+ finalsol.append((HolonomicSequence(sol, u0), p, smallest_n))
1550
+ continue
1551
+ else:
1552
+ finalsol.append((HolonomicSequence(sol, u0), p))
1553
+ continue
1554
+
1555
+ for i in range(len(u0), order):
1556
+
1557
+ if i not in dummys:
1558
+ letter = chr(char) + '_%s' %i
1559
+ dummys[i] = Symbol(letter)
1560
+
1561
+ s = False
1562
+ for j in soleqs:
1563
+ if dummys[i] in j:
1564
+ u0.append(j[dummys[i]])
1565
+ s = True
1566
+ if not s:
1567
+ u0.append(dummys[i])
1568
+ if lb:
1569
+ finalsol.append((HolonomicSequence(sol, u0), p, smallest_n))
1570
+
1571
+ else:
1572
+ finalsol.append((HolonomicSequence(sol, u0), p))
1573
+ char += 1
1574
+ return finalsol
1575
+
1576
+ def series(self, n=6, coefficient=False, order=True, _recur=None):
1577
+ r"""
1578
+ Finds the power series expansion of given holonomic function about :math:`x_0`.
1579
+
1580
+ Explanation
1581
+ ===========
1582
+
1583
+ A list of series might be returned if :math:`x_0` is a regular point with
1584
+ multiple roots of the indicial equation.
1585
+
1586
+ Examples
1587
+ ========
1588
+
1589
+ >>> from sympy.holonomic.holonomic import HolonomicFunction, DifferentialOperators
1590
+ >>> from sympy import QQ
1591
+ >>> from sympy import symbols
1592
+ >>> x = symbols('x')
1593
+ >>> R, Dx = DifferentialOperators(QQ.old_poly_ring(x),'Dx')
1594
+ >>> HolonomicFunction(Dx - 1, x, 0, [1]).series() # e^x
1595
+ 1 + x + x**2/2 + x**3/6 + x**4/24 + x**5/120 + O(x**6)
1596
+ >>> HolonomicFunction(Dx**2 + 1, x, 0, [0, 1]).series(n=8) # sin(x)
1597
+ x - x**3/6 + x**5/120 - x**7/5040 + O(x**8)
1598
+
1599
+ See Also
1600
+ ========
1601
+
1602
+ HolonomicFunction.to_sequence
1603
+ """
1604
+
1605
+ if _recur is None:
1606
+ recurrence = self.to_sequence()
1607
+ else:
1608
+ recurrence = _recur
1609
+
1610
+ if isinstance(recurrence, tuple) and len(recurrence) == 2:
1611
+ recurrence = recurrence[0]
1612
+ constantpower = 0
1613
+ elif isinstance(recurrence, tuple) and len(recurrence) == 3:
1614
+ constantpower = recurrence[1]
1615
+ recurrence = recurrence[0]
1616
+
1617
+ elif len(recurrence) == 1 and len(recurrence[0]) == 2:
1618
+ recurrence = recurrence[0][0]
1619
+ constantpower = 0
1620
+ elif len(recurrence) == 1 and len(recurrence[0]) == 3:
1621
+ constantpower = recurrence[0][1]
1622
+ recurrence = recurrence[0][0]
1623
+ else:
1624
+ return [self.series(_recur=i) for i in recurrence]
1625
+
1626
+ n = n - int(constantpower)
1627
+ l = len(recurrence.u0) - 1
1628
+ k = recurrence.recurrence.order
1629
+ x = self.x
1630
+ x0 = self.x0
1631
+ seq_dmp = recurrence.recurrence.listofpoly
1632
+ R = recurrence.recurrence.parent.base
1633
+ K = R.get_field()
1634
+ seq = [K.new(j.to_list()) for j in seq_dmp]
1635
+ sub = [-seq[i] / seq[k] for i in range(k)]
1636
+ sol = list(recurrence.u0)
1637
+
1638
+ if l + 1 < n:
1639
+ # use the initial conditions to find the next term
1640
+ for i in range(l + 1 - k, n - k):
1641
+ coeff = sum((DMFsubs(sub[j], i) * sol[i + j]
1642
+ for j in range(k) if i + j >= 0), start=S.Zero)
1643
+ sol.append(coeff)
1644
+
1645
+ if coefficient:
1646
+ return sol
1647
+
1648
+ ser = sum((x**(i + constantpower) * j for i, j in enumerate(sol)),
1649
+ start=S.Zero)
1650
+ if order:
1651
+ ser += Order(x**(n + int(constantpower)), x)
1652
+ if x0 != 0:
1653
+ return ser.subs(x, x - x0)
1654
+ return ser
1655
+
1656
+ def _indicial(self):
1657
+ """
1658
+ Computes roots of the Indicial equation.
1659
+ """
1660
+
1661
+ if self.x0 != 0:
1662
+ return self.shift_x(self.x0)._indicial()
1663
+
1664
+ list_coeff = self.annihilator.listofpoly
1665
+ R = self.annihilator.parent.base
1666
+ x = self.x
1667
+ s = R.zero
1668
+ y = R.one
1669
+
1670
+ def _pole_degree(poly):
1671
+ root_all = roots(R.to_sympy(poly), x, filter='Z')
1672
+ if 0 in root_all.keys():
1673
+ return root_all[0]
1674
+ else:
1675
+ return 0
1676
+
1677
+ degree = max(j.degree() for j in list_coeff)
1678
+ inf = 10 * (max(1, degree) + max(1, self.annihilator.order))
1679
+
1680
+ deg = lambda q: inf if q.is_zero else _pole_degree(q)
1681
+ b = min(deg(q) - j for j, q in enumerate(list_coeff))
1682
+
1683
+ for i, j in enumerate(list_coeff):
1684
+ listofdmp = j.all_coeffs()
1685
+ degree = len(listofdmp) - 1
1686
+ if 0 <= i + b <= degree:
1687
+ s = s + listofdmp[degree - i - b] * y
1688
+ y *= R.from_sympy(x - i)
1689
+
1690
+ return roots(R.to_sympy(s), x)
1691
+
1692
+ def evalf(self, points, method='RK4', h=0.05, derivatives=False):
1693
+ r"""
1694
+ Finds numerical value of a holonomic function using numerical methods.
1695
+ (RK4 by default). A set of points (real or complex) must be provided
1696
+ which will be the path for the numerical integration.
1697
+
1698
+ Explanation
1699
+ ===========
1700
+
1701
+ The path should be given as a list :math:`[x_1, x_2, \dots x_n]`. The numerical
1702
+ values will be computed at each point in this order
1703
+ :math:`x_1 \rightarrow x_2 \rightarrow x_3 \dots \rightarrow x_n`.
1704
+
1705
+ Returns values of the function at :math:`x_1, x_2, \dots x_n` in a list.
1706
+
1707
+ Examples
1708
+ ========
1709
+
1710
+ >>> from sympy.holonomic.holonomic import HolonomicFunction, DifferentialOperators
1711
+ >>> from sympy import QQ
1712
+ >>> from sympy import symbols
1713
+ >>> x = symbols('x')
1714
+ >>> R, Dx = DifferentialOperators(QQ.old_poly_ring(x),'Dx')
1715
+
1716
+ A straight line on the real axis from (0 to 1)
1717
+
1718
+ >>> r = [0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1]
1719
+
1720
+ Runge-Kutta 4th order on e^x from 0.1 to 1.
1721
+ Exact solution at 1 is 2.71828182845905
1722
+
1723
+ >>> HolonomicFunction(Dx - 1, x, 0, [1]).evalf(r)
1724
+ [1.10517083333333, 1.22140257085069, 1.34985849706254, 1.49182424008069,
1725
+ 1.64872063859684, 1.82211796209193, 2.01375162659678, 2.22553956329232,
1726
+ 2.45960141378007, 2.71827974413517]
1727
+
1728
+ Euler's method for the same
1729
+
1730
+ >>> HolonomicFunction(Dx - 1, x, 0, [1]).evalf(r, method='Euler')
1731
+ [1.1, 1.21, 1.331, 1.4641, 1.61051, 1.771561, 1.9487171, 2.14358881,
1732
+ 2.357947691, 2.5937424601]
1733
+
1734
+ One can also observe that the value obtained using Runge-Kutta 4th order
1735
+ is much more accurate than Euler's method.
1736
+ """
1737
+
1738
+ from sympy.holonomic.numerical import _evalf
1739
+ lp = False
1740
+
1741
+ # if a point `b` is given instead of a mesh
1742
+ if not hasattr(points, "__iter__"):
1743
+ lp = True
1744
+ b = S(points)
1745
+ if self.x0 == b:
1746
+ return _evalf(self, [b], method=method, derivatives=derivatives)[-1]
1747
+
1748
+ if not b.is_Number:
1749
+ raise NotImplementedError
1750
+
1751
+ a = self.x0
1752
+ if a > b:
1753
+ h = -h
1754
+ n = int((b - a) / h)
1755
+ points = [a + h]
1756
+ for i in range(n - 1):
1757
+ points.append(points[-1] + h)
1758
+
1759
+ for i in roots(self.annihilator.parent.base.to_sympy(self.annihilator.listofpoly[-1]), self.x):
1760
+ if i == self.x0 or i in points:
1761
+ raise SingularityError(self, i)
1762
+
1763
+ if lp:
1764
+ return _evalf(self, points, method=method, derivatives=derivatives)[-1]
1765
+ return _evalf(self, points, method=method, derivatives=derivatives)
1766
+
1767
+ def change_x(self, z):
1768
+ """
1769
+ Changes only the variable of Holonomic Function, for internal
1770
+ purposes. For composition use HolonomicFunction.composition()
1771
+ """
1772
+
1773
+ dom = self.annihilator.parent.base.dom
1774
+ R = dom.old_poly_ring(z)
1775
+ parent, _ = DifferentialOperators(R, 'Dx')
1776
+ sol = [R(j.to_list()) for j in self.annihilator.listofpoly]
1777
+ sol = DifferentialOperator(sol, parent)
1778
+ return HolonomicFunction(sol, z, self.x0, self.y0)
1779
+
1780
+ def shift_x(self, a):
1781
+ """
1782
+ Substitute `x + a` for `x`.
1783
+ """
1784
+
1785
+ x = self.x
1786
+ listaftershift = self.annihilator.listofpoly
1787
+ base = self.annihilator.parent.base
1788
+
1789
+ sol = [base.from_sympy(base.to_sympy(i).subs(x, x + a)) for i in listaftershift]
1790
+ sol = DifferentialOperator(sol, self.annihilator.parent)
1791
+ x0 = self.x0 - a
1792
+ if not self._have_init_cond():
1793
+ return HolonomicFunction(sol, x)
1794
+ return HolonomicFunction(sol, x, x0, self.y0)
1795
+
1796
+ def to_hyper(self, as_list=False, _recur=None):
1797
+ r"""
1798
+ Returns a hypergeometric function (or linear combination of them)
1799
+ representing the given holonomic function.
1800
+
1801
+ Explanation
1802
+ ===========
1803
+
1804
+ Returns an answer of the form:
1805
+ `a_1 \cdot x^{b_1} \cdot{hyper()} + a_2 \cdot x^{b_2} \cdot{hyper()} \dots`
1806
+
1807
+ This is very useful as one can now use ``hyperexpand`` to find the
1808
+ symbolic expressions/functions.
1809
+
1810
+ Examples
1811
+ ========
1812
+
1813
+ >>> from sympy.holonomic.holonomic import HolonomicFunction, DifferentialOperators
1814
+ >>> from sympy import ZZ
1815
+ >>> from sympy import symbols
1816
+ >>> x = symbols('x')
1817
+ >>> R, Dx = DifferentialOperators(ZZ.old_poly_ring(x),'Dx')
1818
+ >>> # sin(x)
1819
+ >>> HolonomicFunction(Dx**2 + 1, x, 0, [0, 1]).to_hyper()
1820
+ x*hyper((), (3/2,), -x**2/4)
1821
+ >>> # exp(x)
1822
+ >>> HolonomicFunction(Dx - 1, x, 0, [1]).to_hyper()
1823
+ hyper((), (), x)
1824
+
1825
+ See Also
1826
+ ========
1827
+
1828
+ from_hyper, from_meijerg
1829
+ """
1830
+
1831
+ if _recur is None:
1832
+ recurrence = self.to_sequence()
1833
+ else:
1834
+ recurrence = _recur
1835
+
1836
+ if isinstance(recurrence, tuple) and len(recurrence) == 2:
1837
+ smallest_n = recurrence[1]
1838
+ recurrence = recurrence[0]
1839
+ constantpower = 0
1840
+ elif isinstance(recurrence, tuple) and len(recurrence) == 3:
1841
+ smallest_n = recurrence[2]
1842
+ constantpower = recurrence[1]
1843
+ recurrence = recurrence[0]
1844
+ elif len(recurrence) == 1 and len(recurrence[0]) == 2:
1845
+ smallest_n = recurrence[0][1]
1846
+ recurrence = recurrence[0][0]
1847
+ constantpower = 0
1848
+ elif len(recurrence) == 1 and len(recurrence[0]) == 3:
1849
+ smallest_n = recurrence[0][2]
1850
+ constantpower = recurrence[0][1]
1851
+ recurrence = recurrence[0][0]
1852
+ else:
1853
+ sol = self.to_hyper(as_list=as_list, _recur=recurrence[0])
1854
+ for i in recurrence[1:]:
1855
+ sol += self.to_hyper(as_list=as_list, _recur=i)
1856
+ return sol
1857
+
1858
+ u0 = recurrence.u0
1859
+ r = recurrence.recurrence
1860
+ x = self.x
1861
+ x0 = self.x0
1862
+
1863
+ # order of the recurrence relation
1864
+ m = r.order
1865
+
1866
+ # when no recurrence exists, and the power series have finite terms
1867
+ if m == 0:
1868
+ nonzeroterms = roots(r.parent.base.to_sympy(r.listofpoly[0]), recurrence.n, filter='R')
1869
+
1870
+ sol = S.Zero
1871
+ for j, i in enumerate(nonzeroterms):
1872
+
1873
+ if i < 0 or not int_valued(i):
1874
+ continue
1875
+
1876
+ i = int(i)
1877
+ if i < len(u0):
1878
+ if isinstance(u0[i], (PolyElement, FracElement)):
1879
+ u0[i] = u0[i].as_expr()
1880
+ sol += u0[i] * x**i
1881
+
1882
+ else:
1883
+ sol += Symbol('C_%s' %j) * x**i
1884
+
1885
+ if isinstance(sol, (PolyElement, FracElement)):
1886
+ sol = sol.as_expr() * x**constantpower
1887
+ else:
1888
+ sol = sol * x**constantpower
1889
+ if as_list:
1890
+ if x0 != 0:
1891
+ return [(sol.subs(x, x - x0), )]
1892
+ return [(sol, )]
1893
+ if x0 != 0:
1894
+ return sol.subs(x, x - x0)
1895
+ return sol
1896
+
1897
+ if smallest_n + m > len(u0):
1898
+ raise NotImplementedError("Can't compute sufficient Initial Conditions")
1899
+
1900
+ # check if the recurrence represents a hypergeometric series
1901
+ if any(i != r.parent.base.zero for i in r.listofpoly[1:-1]):
1902
+ raise NotHyperSeriesError(self, self.x0)
1903
+
1904
+ a = r.listofpoly[0]
1905
+ b = r.listofpoly[-1]
1906
+
1907
+ # the constant multiple of argument of hypergeometric function
1908
+ if isinstance(a.LC(), (PolyElement, FracElement)):
1909
+ c = - (S(a.LC().as_expr()) * m**(a.degree())) / (S(b.LC().as_expr()) * m**(b.degree()))
1910
+ else:
1911
+ c = - (S(a.LC()) * m**(a.degree())) / (S(b.LC()) * m**(b.degree()))
1912
+
1913
+ sol = 0
1914
+
1915
+ arg1 = roots(r.parent.base.to_sympy(a), recurrence.n)
1916
+ arg2 = roots(r.parent.base.to_sympy(b), recurrence.n)
1917
+
1918
+ # iterate through the initial conditions to find
1919
+ # the hypergeometric representation of the given
1920
+ # function.
1921
+ # The answer will be a linear combination
1922
+ # of different hypergeometric series which satisfies
1923
+ # the recurrence.
1924
+ if as_list:
1925
+ listofsol = []
1926
+ for i in range(smallest_n + m):
1927
+
1928
+ # if the recurrence relation doesn't hold for `n = i`,
1929
+ # then a Hypergeometric representation doesn't exist.
1930
+ # add the algebraic term a * x**i to the solution,
1931
+ # where a is u0[i]
1932
+ if i < smallest_n:
1933
+ if as_list:
1934
+ listofsol.append(((S(u0[i]) * x**(i+constantpower)).subs(x, x-x0), ))
1935
+ else:
1936
+ sol += S(u0[i]) * x**i
1937
+ continue
1938
+
1939
+ # if the coefficient u0[i] is zero, then the
1940
+ # independent hypergeomtric series starting with
1941
+ # x**i is not a part of the answer.
1942
+ if S(u0[i]) == 0:
1943
+ continue
1944
+
1945
+ ap = []
1946
+ bq = []
1947
+
1948
+ # substitute m * n + i for n
1949
+ for k in ordered(arg1.keys()):
1950
+ ap.extend([nsimplify((i - k) / m)] * arg1[k])
1951
+
1952
+ for k in ordered(arg2.keys()):
1953
+ bq.extend([nsimplify((i - k) / m)] * arg2[k])
1954
+
1955
+ # convention of (k + 1) in the denominator
1956
+ if 1 in bq:
1957
+ bq.remove(1)
1958
+ else:
1959
+ ap.append(1)
1960
+ if as_list:
1961
+ listofsol.append(((S(u0[i])*x**(i+constantpower)).subs(x, x-x0), (hyper(ap, bq, c*x**m)).subs(x, x-x0)))
1962
+ else:
1963
+ sol += S(u0[i]) * hyper(ap, bq, c * x**m) * x**i
1964
+ if as_list:
1965
+ return listofsol
1966
+ sol = sol * x**constantpower
1967
+ if x0 != 0:
1968
+ return sol.subs(x, x - x0)
1969
+
1970
+ return sol
1971
+
1972
+ def to_expr(self):
1973
+ """
1974
+ Converts a Holonomic Function back to elementary functions.
1975
+
1976
+ Examples
1977
+ ========
1978
+
1979
+ >>> from sympy.holonomic.holonomic import HolonomicFunction, DifferentialOperators
1980
+ >>> from sympy import ZZ
1981
+ >>> from sympy import symbols, S
1982
+ >>> x = symbols('x')
1983
+ >>> R, Dx = DifferentialOperators(ZZ.old_poly_ring(x),'Dx')
1984
+ >>> HolonomicFunction(x**2*Dx**2 + x*Dx + (x**2 - 1), x, 0, [0, S(1)/2]).to_expr()
1985
+ besselj(1, x)
1986
+ >>> HolonomicFunction((1 + x)*Dx**3 + Dx**2, x, 0, [1, 1, 1]).to_expr()
1987
+ x*log(x + 1) + log(x + 1) + 1
1988
+
1989
+ """
1990
+
1991
+ return hyperexpand(self.to_hyper()).simplify()
1992
+
1993
+ def change_ics(self, b, lenics=None):
1994
+ """
1995
+ Changes the point `x0` to ``b`` for initial conditions.
1996
+
1997
+ Examples
1998
+ ========
1999
+
2000
+ >>> from sympy.holonomic import expr_to_holonomic
2001
+ >>> from sympy import symbols, sin, exp
2002
+ >>> x = symbols('x')
2003
+
2004
+ >>> expr_to_holonomic(sin(x)).change_ics(1)
2005
+ HolonomicFunction((1) + (1)*Dx**2, x, 1, [sin(1), cos(1)])
2006
+
2007
+ >>> expr_to_holonomic(exp(x)).change_ics(2)
2008
+ HolonomicFunction((-1) + (1)*Dx, x, 2, [exp(2)])
2009
+ """
2010
+
2011
+ symbolic = True
2012
+
2013
+ if lenics is None and len(self.y0) > self.annihilator.order:
2014
+ lenics = len(self.y0)
2015
+ dom = self.annihilator.parent.base.domain
2016
+
2017
+ try:
2018
+ sol = expr_to_holonomic(self.to_expr(), x=self.x, x0=b, lenics=lenics, domain=dom)
2019
+ except (NotPowerSeriesError, NotHyperSeriesError):
2020
+ symbolic = False
2021
+
2022
+ if symbolic and sol.x0 == b:
2023
+ return sol
2024
+
2025
+ y0 = self.evalf(b, derivatives=True)
2026
+ return HolonomicFunction(self.annihilator, self.x, b, y0)
2027
+
2028
+ def to_meijerg(self):
2029
+ """
2030
+ Returns a linear combination of Meijer G-functions.
2031
+
2032
+ Examples
2033
+ ========
2034
+
2035
+ >>> from sympy.holonomic import expr_to_holonomic
2036
+ >>> from sympy import sin, cos, hyperexpand, log, symbols
2037
+ >>> x = symbols('x')
2038
+ >>> hyperexpand(expr_to_holonomic(cos(x) + sin(x)).to_meijerg())
2039
+ sin(x) + cos(x)
2040
+ >>> hyperexpand(expr_to_holonomic(log(x)).to_meijerg()).simplify()
2041
+ log(x)
2042
+
2043
+ See Also
2044
+ ========
2045
+
2046
+ to_hyper
2047
+ """
2048
+
2049
+ # convert to hypergeometric first
2050
+ rep = self.to_hyper(as_list=True)
2051
+ sol = S.Zero
2052
+
2053
+ for i in rep:
2054
+ if len(i) == 1:
2055
+ sol += i[0]
2056
+
2057
+ elif len(i) == 2:
2058
+ sol += i[0] * _hyper_to_meijerg(i[1])
2059
+
2060
+ return sol
2061
+
2062
+
2063
+ def from_hyper(func, x0=0, evalf=False):
2064
+ r"""
2065
+ Converts a hypergeometric function to holonomic.
2066
+ ``func`` is the Hypergeometric Function and ``x0`` is the point at
2067
+ which initial conditions are required.
2068
+
2069
+ Examples
2070
+ ========
2071
+
2072
+ >>> from sympy.holonomic.holonomic import from_hyper
2073
+ >>> from sympy import symbols, hyper, S
2074
+ >>> x = symbols('x')
2075
+ >>> from_hyper(hyper([], [S(3)/2], x**2/4))
2076
+ HolonomicFunction((-x) + (2)*Dx + (x)*Dx**2, x, 1, [sinh(1), -sinh(1) + cosh(1)])
2077
+ """
2078
+
2079
+ a = func.ap
2080
+ b = func.bq
2081
+ z = func.args[2]
2082
+ x = z.atoms(Symbol).pop()
2083
+ R, Dx = DifferentialOperators(QQ.old_poly_ring(x), 'Dx')
2084
+
2085
+ # generalized hypergeometric differential equation
2086
+ xDx = x*Dx
2087
+ r1 = 1
2088
+ for ai in a: # XXX gives sympify error if Mul is used with list of all factors
2089
+ r1 *= xDx + ai
2090
+ xDx_1 = xDx - 1
2091
+ # r2 = Mul(*([Dx] + [xDx_1 + bi for bi in b])) # XXX gives sympify error
2092
+ r2 = Dx
2093
+ for bi in b:
2094
+ r2 *= xDx_1 + bi
2095
+ sol = r1 - r2
2096
+
2097
+ simp = hyperexpand(func)
2098
+
2099
+ if simp in (Infinity, NegativeInfinity):
2100
+ return HolonomicFunction(sol, x).composition(z)
2101
+
2102
+ # if the function is known symbolically
2103
+ if not isinstance(simp, hyper):
2104
+ y0 = _find_conditions(simp, x, x0, sol.order, use_limit=False)
2105
+ while not y0:
2106
+ # if values don't exist at 0, then try to find initial
2107
+ # conditions at 1. If it doesn't exist at 1 too then
2108
+ # try 2 and so on.
2109
+ x0 += 1
2110
+ y0 = _find_conditions(simp, x, x0, sol.order, use_limit=False)
2111
+
2112
+ return HolonomicFunction(sol, x).composition(z, x0, y0)
2113
+
2114
+ if isinstance(simp, hyper):
2115
+ x0 = 1
2116
+ # use evalf if the function can't be simplified
2117
+ y0 = _find_conditions(simp, x, x0, sol.order, evalf, use_limit=False)
2118
+ while not y0:
2119
+ x0 += 1
2120
+ y0 = _find_conditions(simp, x, x0, sol.order, evalf, use_limit=False)
2121
+ return HolonomicFunction(sol, x).composition(z, x0, y0)
2122
+
2123
+ return HolonomicFunction(sol, x).composition(z)
2124
+
2125
+
2126
+ def from_meijerg(func, x0=0, evalf=False, initcond=True, domain=QQ):
2127
+ """
2128
+ Converts a Meijer G-function to Holonomic.
2129
+ ``func`` is the G-Function and ``x0`` is the point at
2130
+ which initial conditions are required.
2131
+
2132
+ Examples
2133
+ ========
2134
+
2135
+ >>> from sympy.holonomic.holonomic import from_meijerg
2136
+ >>> from sympy import symbols, meijerg, S
2137
+ >>> x = symbols('x')
2138
+ >>> from_meijerg(meijerg(([], []), ([S(1)/2], [0]), x**2/4))
2139
+ HolonomicFunction((1) + (1)*Dx**2, x, 0, [0, 1/sqrt(pi)])
2140
+ """
2141
+
2142
+ a = func.ap
2143
+ b = func.bq
2144
+ n = len(func.an)
2145
+ m = len(func.bm)
2146
+ p = len(a)
2147
+ z = func.args[2]
2148
+ x = z.atoms(Symbol).pop()
2149
+ R, Dx = DifferentialOperators(domain.old_poly_ring(x), 'Dx')
2150
+
2151
+ # compute the differential equation satisfied by the
2152
+ # Meijer G-function.
2153
+ xDx = x*Dx
2154
+ xDx1 = xDx + 1
2155
+ r1 = x*(-1)**(m + n - p)
2156
+ for ai in a: # XXX gives sympify error if args given in list
2157
+ r1 *= xDx1 - ai
2158
+ # r2 = Mul(*[xDx - bi for bi in b]) # gives sympify error
2159
+ r2 = 1
2160
+ for bi in b:
2161
+ r2 *= xDx - bi
2162
+ sol = r1 - r2
2163
+
2164
+ if not initcond:
2165
+ return HolonomicFunction(sol, x).composition(z)
2166
+
2167
+ simp = hyperexpand(func)
2168
+
2169
+ if simp in (Infinity, NegativeInfinity):
2170
+ return HolonomicFunction(sol, x).composition(z)
2171
+
2172
+ # computing initial conditions
2173
+ if not isinstance(simp, meijerg):
2174
+ y0 = _find_conditions(simp, x, x0, sol.order, use_limit=False)
2175
+ while not y0:
2176
+ x0 += 1
2177
+ y0 = _find_conditions(simp, x, x0, sol.order, use_limit=False)
2178
+
2179
+ return HolonomicFunction(sol, x).composition(z, x0, y0)
2180
+
2181
+ if isinstance(simp, meijerg):
2182
+ x0 = 1
2183
+ y0 = _find_conditions(simp, x, x0, sol.order, evalf, use_limit=False)
2184
+ while not y0:
2185
+ x0 += 1
2186
+ y0 = _find_conditions(simp, x, x0, sol.order, evalf, use_limit=False)
2187
+
2188
+ return HolonomicFunction(sol, x).composition(z, x0, y0)
2189
+
2190
+ return HolonomicFunction(sol, x).composition(z)
2191
+
2192
+
2193
+ x_1 = Dummy('x_1')
2194
+ _lookup_table = None
2195
+ domain_for_table = None
2196
+ from sympy.integrals.meijerint import _mytype
2197
+
2198
+
2199
+ def expr_to_holonomic(func, x=None, x0=0, y0=None, lenics=None, domain=None, initcond=True):
2200
+ """
2201
+ Converts a function or an expression to a holonomic function.
2202
+
2203
+ Parameters
2204
+ ==========
2205
+
2206
+ func:
2207
+ The expression to be converted.
2208
+ x:
2209
+ variable for the function.
2210
+ x0:
2211
+ point at which initial condition must be computed.
2212
+ y0:
2213
+ One can optionally provide initial condition if the method
2214
+ is not able to do it automatically.
2215
+ lenics:
2216
+ Number of terms in the initial condition. By default it is
2217
+ equal to the order of the annihilator.
2218
+ domain:
2219
+ Ground domain for the polynomials in ``x`` appearing as coefficients
2220
+ in the annihilator.
2221
+ initcond:
2222
+ Set it false if you do not want the initial conditions to be computed.
2223
+
2224
+ Examples
2225
+ ========
2226
+
2227
+ >>> from sympy.holonomic.holonomic import expr_to_holonomic
2228
+ >>> from sympy import sin, exp, symbols
2229
+ >>> x = symbols('x')
2230
+ >>> expr_to_holonomic(sin(x))
2231
+ HolonomicFunction((1) + (1)*Dx**2, x, 0, [0, 1])
2232
+ >>> expr_to_holonomic(exp(x))
2233
+ HolonomicFunction((-1) + (1)*Dx, x, 0, [1])
2234
+
2235
+ See Also
2236
+ ========
2237
+
2238
+ sympy.integrals.meijerint._rewrite1, _convert_poly_rat_alg, _create_table
2239
+ """
2240
+ func = sympify(func)
2241
+ syms = func.free_symbols
2242
+
2243
+ if not x:
2244
+ if len(syms) == 1:
2245
+ x= syms.pop()
2246
+ else:
2247
+ raise ValueError("Specify the variable for the function")
2248
+ elif x in syms:
2249
+ syms.remove(x)
2250
+
2251
+ extra_syms = list(syms)
2252
+
2253
+ if domain is None:
2254
+ if func.has(Float):
2255
+ domain = RR
2256
+ else:
2257
+ domain = QQ
2258
+ if len(extra_syms) != 0:
2259
+ domain = domain[extra_syms].get_field()
2260
+
2261
+ # try to convert if the function is polynomial or rational
2262
+ solpoly = _convert_poly_rat_alg(func, x, x0=x0, y0=y0, lenics=lenics, domain=domain, initcond=initcond)
2263
+ if solpoly:
2264
+ return solpoly
2265
+
2266
+ # create the lookup table
2267
+ global _lookup_table, domain_for_table
2268
+ if not _lookup_table:
2269
+ domain_for_table = domain
2270
+ _lookup_table = {}
2271
+ _create_table(_lookup_table, domain=domain)
2272
+ elif domain != domain_for_table:
2273
+ domain_for_table = domain
2274
+ _lookup_table = {}
2275
+ _create_table(_lookup_table, domain=domain)
2276
+
2277
+ # use the table directly to convert to Holonomic
2278
+ if func.is_Function:
2279
+ f = func.subs(x, x_1)
2280
+ t = _mytype(f, x_1)
2281
+ if t in _lookup_table:
2282
+ l = _lookup_table[t]
2283
+ sol = l[0][1].change_x(x)
2284
+ else:
2285
+ sol = _convert_meijerint(func, x, initcond=False, domain=domain)
2286
+ if not sol:
2287
+ raise NotImplementedError
2288
+ if y0:
2289
+ sol.y0 = y0
2290
+ if y0 or not initcond:
2291
+ sol.x0 = x0
2292
+ return sol
2293
+ if not lenics:
2294
+ lenics = sol.annihilator.order
2295
+ _y0 = _find_conditions(func, x, x0, lenics)
2296
+ while not _y0:
2297
+ x0 += 1
2298
+ _y0 = _find_conditions(func, x, x0, lenics)
2299
+ return HolonomicFunction(sol.annihilator, x, x0, _y0)
2300
+
2301
+ if y0 or not initcond:
2302
+ sol = sol.composition(func.args[0])
2303
+ if y0:
2304
+ sol.y0 = y0
2305
+ sol.x0 = x0
2306
+ return sol
2307
+ if not lenics:
2308
+ lenics = sol.annihilator.order
2309
+
2310
+ _y0 = _find_conditions(func, x, x0, lenics)
2311
+ while not _y0:
2312
+ x0 += 1
2313
+ _y0 = _find_conditions(func, x, x0, lenics)
2314
+ return sol.composition(func.args[0], x0, _y0)
2315
+
2316
+ # iterate through the expression recursively
2317
+ args = func.args
2318
+ f = func.func
2319
+ sol = expr_to_holonomic(args[0], x=x, initcond=False, domain=domain)
2320
+
2321
+ if f is Add:
2322
+ for i in range(1, len(args)):
2323
+ sol += expr_to_holonomic(args[i], x=x, initcond=False, domain=domain)
2324
+
2325
+ elif f is Mul:
2326
+ for i in range(1, len(args)):
2327
+ sol *= expr_to_holonomic(args[i], x=x, initcond=False, domain=domain)
2328
+
2329
+ elif f is Pow:
2330
+ sol = sol**args[1]
2331
+ sol.x0 = x0
2332
+ if not sol:
2333
+ raise NotImplementedError
2334
+ if y0:
2335
+ sol.y0 = y0
2336
+ if y0 or not initcond:
2337
+ return sol
2338
+ if sol.y0:
2339
+ return sol
2340
+ if not lenics:
2341
+ lenics = sol.annihilator.order
2342
+ if sol.annihilator.is_singular(x0):
2343
+ r = sol._indicial()
2344
+ l = list(r)
2345
+ if len(r) == 1 and r[l[0]] == S.One:
2346
+ r = l[0]
2347
+ g = func / (x - x0)**r
2348
+ singular_ics = _find_conditions(g, x, x0, lenics)
2349
+ singular_ics = [j / factorial(i) for i, j in enumerate(singular_ics)]
2350
+ y0 = {r:singular_ics}
2351
+ return HolonomicFunction(sol.annihilator, x, x0, y0)
2352
+
2353
+ _y0 = _find_conditions(func, x, x0, lenics)
2354
+ while not _y0:
2355
+ x0 += 1
2356
+ _y0 = _find_conditions(func, x, x0, lenics)
2357
+
2358
+ return HolonomicFunction(sol.annihilator, x, x0, _y0)
2359
+
2360
+
2361
+ ## Some helper functions ##
2362
+
2363
+ def _normalize(list_of, parent, negative=True):
2364
+ """
2365
+ Normalize a given annihilator
2366
+ """
2367
+
2368
+ num = []
2369
+ denom = []
2370
+ base = parent.base
2371
+ K = base.get_field()
2372
+ lcm_denom = base.from_sympy(S.One)
2373
+ list_of_coeff = []
2374
+
2375
+ # convert polynomials to the elements of associated
2376
+ # fraction field
2377
+ for i, j in enumerate(list_of):
2378
+ if isinstance(j, base.dtype):
2379
+ list_of_coeff.append(K.new(j.to_list()))
2380
+ elif not isinstance(j, K.dtype):
2381
+ list_of_coeff.append(K.from_sympy(sympify(j)))
2382
+ else:
2383
+ list_of_coeff.append(j)
2384
+
2385
+ # corresponding numerators of the sequence of polynomials
2386
+ num.append(list_of_coeff[i].numer())
2387
+
2388
+ # corresponding denominators
2389
+ denom.append(list_of_coeff[i].denom())
2390
+
2391
+ # lcm of denominators in the coefficients
2392
+ for i in denom:
2393
+ lcm_denom = i.lcm(lcm_denom)
2394
+
2395
+ if negative:
2396
+ lcm_denom = -lcm_denom
2397
+
2398
+ lcm_denom = K.new(lcm_denom.to_list())
2399
+
2400
+ # multiply the coefficients with lcm
2401
+ for i, j in enumerate(list_of_coeff):
2402
+ list_of_coeff[i] = j * lcm_denom
2403
+
2404
+ gcd_numer = base((list_of_coeff[-1].numer() / list_of_coeff[-1].denom()).to_list())
2405
+
2406
+ # gcd of numerators in the coefficients
2407
+ for i in num:
2408
+ gcd_numer = i.gcd(gcd_numer)
2409
+
2410
+ gcd_numer = K.new(gcd_numer.to_list())
2411
+
2412
+ # divide all the coefficients by the gcd
2413
+ for i, j in enumerate(list_of_coeff):
2414
+ frac_ans = j / gcd_numer
2415
+ list_of_coeff[i] = base((frac_ans.numer() / frac_ans.denom()).to_list())
2416
+
2417
+ return DifferentialOperator(list_of_coeff, parent)
2418
+
2419
+
2420
+ def _derivate_diff_eq(listofpoly, K):
2421
+ """
2422
+ Let a differential equation a0(x)y(x) + a1(x)y'(x) + ... = 0
2423
+ where a0, a1,... are polynomials or rational functions. The function
2424
+ returns b0, b1, b2... such that the differential equation
2425
+ b0(x)y(x) + b1(x)y'(x) +... = 0 is formed after differentiating the
2426
+ former equation.
2427
+ """
2428
+
2429
+ sol = []
2430
+ a = len(listofpoly) - 1
2431
+ sol.append(DMFdiff(listofpoly[0], K))
2432
+
2433
+ for i, j in enumerate(listofpoly[1:]):
2434
+ sol.append(DMFdiff(j, K) + listofpoly[i])
2435
+
2436
+ sol.append(listofpoly[a])
2437
+ return sol
2438
+
2439
+
2440
+ def _hyper_to_meijerg(func):
2441
+ """
2442
+ Converts a `hyper` to meijerg.
2443
+ """
2444
+ ap = func.ap
2445
+ bq = func.bq
2446
+
2447
+ if any(i <= 0 and int(i) == i for i in ap):
2448
+ return hyperexpand(func)
2449
+
2450
+ z = func.args[2]
2451
+
2452
+ # parameters of the `meijerg` function.
2453
+ an = (1 - i for i in ap)
2454
+ anp = ()
2455
+ bm = (S.Zero, )
2456
+ bmq = (1 - i for i in bq)
2457
+
2458
+ k = S.One
2459
+
2460
+ for i in bq:
2461
+ k = k * gamma(i)
2462
+
2463
+ for i in ap:
2464
+ k = k / gamma(i)
2465
+
2466
+ return k * meijerg(an, anp, bm, bmq, -z)
2467
+
2468
+
2469
+ def _add_lists(list1, list2):
2470
+ """Takes polynomial sequences of two annihilators a and b and returns
2471
+ the list of polynomials of sum of a and b.
2472
+ """
2473
+ if len(list1) <= len(list2):
2474
+ sol = [a + b for a, b in zip(list1, list2)] + list2[len(list1):]
2475
+ else:
2476
+ sol = [a + b for a, b in zip(list1, list2)] + list1[len(list2):]
2477
+ return sol
2478
+
2479
+
2480
+ def _extend_y0(Holonomic, n):
2481
+ """
2482
+ Tries to find more initial conditions by substituting the initial
2483
+ value point in the differential equation.
2484
+ """
2485
+
2486
+ if Holonomic.annihilator.is_singular(Holonomic.x0) or Holonomic.is_singularics() == True:
2487
+ return Holonomic.y0
2488
+
2489
+ annihilator = Holonomic.annihilator
2490
+ a = annihilator.order
2491
+
2492
+ listofpoly = []
2493
+
2494
+ y0 = Holonomic.y0
2495
+ R = annihilator.parent.base
2496
+ K = R.get_field()
2497
+
2498
+ for j in annihilator.listofpoly:
2499
+ if isinstance(j, annihilator.parent.base.dtype):
2500
+ listofpoly.append(K.new(j.to_list()))
2501
+
2502
+ if len(y0) < a or n <= len(y0):
2503
+ return y0
2504
+ list_red = [-listofpoly[i] / listofpoly[a]
2505
+ for i in range(a)]
2506
+ y1 = y0[:min(len(y0), a)]
2507
+ for _ in range(n - a):
2508
+ sol = 0
2509
+ for a, b in zip(y1, list_red):
2510
+ r = DMFsubs(b, Holonomic.x0)
2511
+ if not getattr(r, 'is_finite', True):
2512
+ return y0
2513
+ if isinstance(r, (PolyElement, FracElement)):
2514
+ r = r.as_expr()
2515
+ sol += a * r
2516
+ y1.append(sol)
2517
+ list_red = _derivate_diff_eq(list_red, K)
2518
+ return y0 + y1[len(y0):]
2519
+
2520
+
2521
+ def DMFdiff(frac, K):
2522
+ # differentiate a DMF object represented as p/q
2523
+ if not isinstance(frac, DMF):
2524
+ return frac.diff()
2525
+
2526
+ p = K.numer(frac)
2527
+ q = K.denom(frac)
2528
+ sol_num = - p * q.diff() + q * p.diff()
2529
+ sol_denom = q**2
2530
+ return K((sol_num.to_list(), sol_denom.to_list()))
2531
+
2532
+
2533
+ def DMFsubs(frac, x0, mpm=False):
2534
+ # substitute the point x0 in DMF object of the form p/q
2535
+ if not isinstance(frac, DMF):
2536
+ return frac
2537
+
2538
+ p = frac.num
2539
+ q = frac.den
2540
+ sol_p = S.Zero
2541
+ sol_q = S.Zero
2542
+
2543
+ if mpm:
2544
+ from mpmath import mp
2545
+
2546
+ for i, j in enumerate(reversed(p)):
2547
+ if mpm:
2548
+ j = sympify(j)._to_mpmath(mp.prec)
2549
+ sol_p += j * x0**i
2550
+
2551
+ for i, j in enumerate(reversed(q)):
2552
+ if mpm:
2553
+ j = sympify(j)._to_mpmath(mp.prec)
2554
+ sol_q += j * x0**i
2555
+
2556
+ if isinstance(sol_p, (PolyElement, FracElement)):
2557
+ sol_p = sol_p.as_expr()
2558
+ if isinstance(sol_q, (PolyElement, FracElement)):
2559
+ sol_q = sol_q.as_expr()
2560
+
2561
+ return sol_p / sol_q
2562
+
2563
+
2564
+ def _convert_poly_rat_alg(func, x, x0=0, y0=None, lenics=None, domain=QQ, initcond=True):
2565
+ """
2566
+ Converts polynomials, rationals and algebraic functions to holonomic.
2567
+ """
2568
+
2569
+ ispoly = func.is_polynomial()
2570
+ if not ispoly:
2571
+ israt = func.is_rational_function()
2572
+ else:
2573
+ israt = True
2574
+
2575
+ if not (ispoly or israt):
2576
+ basepoly, ratexp = func.as_base_exp()
2577
+ if basepoly.is_polynomial() and ratexp.is_Number:
2578
+ if isinstance(ratexp, Float):
2579
+ ratexp = nsimplify(ratexp)
2580
+ m, n = ratexp.p, ratexp.q
2581
+ is_alg = True
2582
+ else:
2583
+ is_alg = False
2584
+ else:
2585
+ is_alg = True
2586
+
2587
+ if not (ispoly or israt or is_alg):
2588
+ return None
2589
+
2590
+ R = domain.old_poly_ring(x)
2591
+ _, Dx = DifferentialOperators(R, 'Dx')
2592
+
2593
+ # if the function is constant
2594
+ if not func.has(x):
2595
+ return HolonomicFunction(Dx, x, 0, [func])
2596
+
2597
+ if ispoly:
2598
+ # differential equation satisfied by polynomial
2599
+ sol = func * Dx - func.diff(x)
2600
+ sol = _normalize(sol.listofpoly, sol.parent, negative=False)
2601
+ is_singular = sol.is_singular(x0)
2602
+
2603
+ # try to compute the conditions for singular points
2604
+ if y0 is None and x0 == 0 and is_singular:
2605
+ rep = R.from_sympy(func).to_list()
2606
+ for i, j in enumerate(reversed(rep)):
2607
+ if j == 0:
2608
+ continue
2609
+ coeff = list(reversed(rep))[i:]
2610
+ indicial = i
2611
+ break
2612
+ for i, j in enumerate(coeff):
2613
+ if isinstance(j, (PolyElement, FracElement)):
2614
+ coeff[i] = j.as_expr()
2615
+ y0 = {indicial: S(coeff)}
2616
+
2617
+ elif israt:
2618
+ p, q = func.as_numer_denom()
2619
+ # differential equation satisfied by rational
2620
+ sol = p * q * Dx + p * q.diff(x) - q * p.diff(x)
2621
+ sol = _normalize(sol.listofpoly, sol.parent, negative=False)
2622
+
2623
+ elif is_alg:
2624
+ sol = n * (x / m) * Dx - 1
2625
+ sol = HolonomicFunction(sol, x).composition(basepoly).annihilator
2626
+ is_singular = sol.is_singular(x0)
2627
+
2628
+ # try to compute the conditions for singular points
2629
+ if y0 is None and x0 == 0 and is_singular and \
2630
+ (lenics is None or lenics <= 1):
2631
+ rep = R.from_sympy(basepoly).to_list()
2632
+ for i, j in enumerate(reversed(rep)):
2633
+ if j == 0:
2634
+ continue
2635
+ if isinstance(j, (PolyElement, FracElement)):
2636
+ j = j.as_expr()
2637
+
2638
+ coeff = S(j)**ratexp
2639
+ indicial = S(i) * ratexp
2640
+ break
2641
+ if isinstance(coeff, (PolyElement, FracElement)):
2642
+ coeff = coeff.as_expr()
2643
+ y0 = {indicial: S([coeff])}
2644
+
2645
+ if y0 or not initcond:
2646
+ return HolonomicFunction(sol, x, x0, y0)
2647
+
2648
+ if not lenics:
2649
+ lenics = sol.order
2650
+
2651
+ if sol.is_singular(x0):
2652
+ r = HolonomicFunction(sol, x, x0)._indicial()
2653
+ l = list(r)
2654
+ if len(r) == 1 and r[l[0]] == S.One:
2655
+ r = l[0]
2656
+ g = func / (x - x0)**r
2657
+ singular_ics = _find_conditions(g, x, x0, lenics)
2658
+ singular_ics = [j / factorial(i) for i, j in enumerate(singular_ics)]
2659
+ y0 = {r:singular_ics}
2660
+ return HolonomicFunction(sol, x, x0, y0)
2661
+
2662
+ y0 = _find_conditions(func, x, x0, lenics)
2663
+ while not y0:
2664
+ x0 += 1
2665
+ y0 = _find_conditions(func, x, x0, lenics)
2666
+
2667
+ return HolonomicFunction(sol, x, x0, y0)
2668
+
2669
+
2670
+ def _convert_meijerint(func, x, initcond=True, domain=QQ):
2671
+ args = meijerint._rewrite1(func, x)
2672
+
2673
+ if args:
2674
+ fac, po, g, _ = args
2675
+ else:
2676
+ return None
2677
+
2678
+ # lists for sum of meijerg functions
2679
+ fac_list = [fac * i[0] for i in g]
2680
+ t = po.as_base_exp()
2681
+ s = t[1] if t[0] == x else S.Zero
2682
+ po_list = [s + i[1] for i in g]
2683
+ G_list = [i[2] for i in g]
2684
+
2685
+ # finds meijerg representation of x**s * meijerg(a1 ... ap, b1 ... bq, z)
2686
+ def _shift(func, s):
2687
+ z = func.args[-1]
2688
+ if z.has(I):
2689
+ z = z.subs(exp_polar, exp)
2690
+
2691
+ d = z.collect(x, evaluate=False)
2692
+ b = list(d)[0]
2693
+ a = d[b]
2694
+
2695
+ t = b.as_base_exp()
2696
+ b = t[1] if t[0] == x else S.Zero
2697
+ r = s / b
2698
+ an = (i + r for i in func.args[0][0])
2699
+ ap = (i + r for i in func.args[0][1])
2700
+ bm = (i + r for i in func.args[1][0])
2701
+ bq = (i + r for i in func.args[1][1])
2702
+
2703
+ return a**-r, meijerg((an, ap), (bm, bq), z)
2704
+
2705
+ coeff, m = _shift(G_list[0], po_list[0])
2706
+ sol = fac_list[0] * coeff * from_meijerg(m, initcond=initcond, domain=domain)
2707
+
2708
+ # add all the meijerg functions after converting to holonomic
2709
+ for i in range(1, len(G_list)):
2710
+ coeff, m = _shift(G_list[i], po_list[i])
2711
+ sol += fac_list[i] * coeff * from_meijerg(m, initcond=initcond, domain=domain)
2712
+
2713
+ return sol
2714
+
2715
+
2716
+ def _create_table(table, domain=QQ):
2717
+ """
2718
+ Creates the look-up table. For a similar implementation
2719
+ see meijerint._create_lookup_table.
2720
+ """
2721
+
2722
+ def add(formula, annihilator, arg, x0=0, y0=()):
2723
+ """
2724
+ Adds a formula in the dictionary
2725
+ """
2726
+ table.setdefault(_mytype(formula, x_1), []).append((formula,
2727
+ HolonomicFunction(annihilator, arg, x0, y0)))
2728
+
2729
+ R = domain.old_poly_ring(x_1)
2730
+ _, Dx = DifferentialOperators(R, 'Dx')
2731
+
2732
+ # add some basic functions
2733
+ add(sin(x_1), Dx**2 + 1, x_1, 0, [0, 1])
2734
+ add(cos(x_1), Dx**2 + 1, x_1, 0, [1, 0])
2735
+ add(exp(x_1), Dx - 1, x_1, 0, 1)
2736
+ add(log(x_1), Dx + x_1*Dx**2, x_1, 1, [0, 1])
2737
+
2738
+ add(erf(x_1), 2*x_1*Dx + Dx**2, x_1, 0, [0, 2/sqrt(pi)])
2739
+ add(erfc(x_1), 2*x_1*Dx + Dx**2, x_1, 0, [1, -2/sqrt(pi)])
2740
+ add(erfi(x_1), -2*x_1*Dx + Dx**2, x_1, 0, [0, 2/sqrt(pi)])
2741
+
2742
+ add(sinh(x_1), Dx**2 - 1, x_1, 0, [0, 1])
2743
+ add(cosh(x_1), Dx**2 - 1, x_1, 0, [1, 0])
2744
+
2745
+ add(sinc(x_1), x_1 + 2*Dx + x_1*Dx**2, x_1)
2746
+
2747
+ add(Si(x_1), x_1*Dx + 2*Dx**2 + x_1*Dx**3, x_1)
2748
+ add(Ci(x_1), x_1*Dx + 2*Dx**2 + x_1*Dx**3, x_1)
2749
+
2750
+ add(Shi(x_1), -x_1*Dx + 2*Dx**2 + x_1*Dx**3, x_1)
2751
+
2752
+
2753
+ def _find_conditions(func, x, x0, order, evalf=False, use_limit=True):
2754
+ y0 = []
2755
+ for _ in range(order):
2756
+ val = func.subs(x, x0)
2757
+ if evalf:
2758
+ val = val.evalf()
2759
+ if use_limit and isinstance(val, NaN):
2760
+ val = limit(func, x, x0)
2761
+ if val.is_finite is False or isinstance(val, NaN):
2762
+ return None
2763
+ y0.append(val)
2764
+ func = func.diff(x)
2765
+ return y0
.venv/lib/python3.12/site-packages/sympy/holonomic/holonomicerrors.py ADDED
@@ -0,0 +1,49 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ """ Common Exceptions for `holonomic` module. """
2
+
3
+ class BaseHolonomicError(Exception):
4
+
5
+ def new(self, *args):
6
+ raise NotImplementedError("abstract base class")
7
+
8
+ class NotPowerSeriesError(BaseHolonomicError):
9
+
10
+ def __init__(self, holonomic, x0):
11
+ self.holonomic = holonomic
12
+ self.x0 = x0
13
+
14
+ def __str__(self):
15
+ s = 'A Power Series does not exists for '
16
+ s += str(self.holonomic)
17
+ s += ' about %s.' %self.x0
18
+ return s
19
+
20
+ class NotHolonomicError(BaseHolonomicError):
21
+
22
+ def __init__(self, m):
23
+ self.m = m
24
+
25
+ def __str__(self):
26
+ return self.m
27
+
28
+ class SingularityError(BaseHolonomicError):
29
+
30
+ def __init__(self, holonomic, x0):
31
+ self.holonomic = holonomic
32
+ self.x0 = x0
33
+
34
+ def __str__(self):
35
+ s = str(self.holonomic)
36
+ s += ' has a singularity at %s.' %self.x0
37
+ return s
38
+
39
+ class NotHyperSeriesError(BaseHolonomicError):
40
+
41
+ def __init__(self, holonomic, x0):
42
+ self.holonomic = holonomic
43
+ self.x0 = x0
44
+
45
+ def __str__(self):
46
+ s = 'Power series expansion of '
47
+ s += str(self.holonomic)
48
+ s += ' about %s is not hypergeometric' %self.x0
49
+ return s
.venv/lib/python3.12/site-packages/sympy/holonomic/numerical.py ADDED
@@ -0,0 +1,98 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ """Numerical Methods for Holonomic Functions"""
2
+
3
+ from sympy.core.sympify import sympify
4
+ from sympy.holonomic.holonomic import DMFsubs
5
+
6
+ from mpmath import mp
7
+
8
+
9
+ def _evalf(func, points, derivatives=False, method='RK4'):
10
+ """
11
+ Numerical methods for numerical integration along a given set of
12
+ points in the complex plane.
13
+ """
14
+
15
+ ann = func.annihilator
16
+ a = ann.order
17
+ R = ann.parent.base
18
+ K = R.get_field()
19
+
20
+ if method == 'Euler':
21
+ meth = _euler
22
+ else:
23
+ meth = _rk4
24
+
25
+ dmf = [K.new(j.to_list()) for j in ann.listofpoly]
26
+ red = [-dmf[i] / dmf[a] for i in range(a)]
27
+
28
+ y0 = func.y0
29
+ if len(y0) < a:
30
+ raise TypeError("Not Enough Initial Conditions")
31
+ x0 = func.x0
32
+ sol = [meth(red, x0, points[0], y0, a)]
33
+
34
+ for i, j in enumerate(points[1:]):
35
+ sol.append(meth(red, points[i], j, sol[-1], a))
36
+
37
+ if not derivatives:
38
+ return [sympify(i[0]) for i in sol]
39
+ else:
40
+ return sympify(sol)
41
+
42
+
43
+ def _euler(red, x0, x1, y0, a):
44
+ """
45
+ Euler's method for numerical integration.
46
+ From x0 to x1 with initial values given at x0 as vector y0.
47
+ """
48
+
49
+ A = sympify(x0)._to_mpmath(mp.prec)
50
+ B = sympify(x1)._to_mpmath(mp.prec)
51
+ y_0 = [sympify(i)._to_mpmath(mp.prec) for i in y0]
52
+ h = B - A
53
+ f_0 = y_0[1:]
54
+ f_0_n = 0
55
+
56
+ for i in range(a):
57
+ f_0_n += sympify(DMFsubs(red[i], A, mpm=True))._to_mpmath(mp.prec) * y_0[i]
58
+ f_0.append(f_0_n)
59
+
60
+ return [y_0[i] + h * f_0[i] for i in range(a)]
61
+
62
+
63
+ def _rk4(red, x0, x1, y0, a):
64
+ """
65
+ Runge-Kutta 4th order numerical method.
66
+ """
67
+
68
+ A = sympify(x0)._to_mpmath(mp.prec)
69
+ B = sympify(x1)._to_mpmath(mp.prec)
70
+ y_0 = [sympify(i)._to_mpmath(mp.prec) for i in y0]
71
+ h = B - A
72
+
73
+ f_0_n = 0
74
+ f_1_n = 0
75
+ f_2_n = 0
76
+ f_3_n = 0
77
+
78
+ f_0 = y_0[1:]
79
+ for i in range(a):
80
+ f_0_n += sympify(DMFsubs(red[i], A, mpm=True))._to_mpmath(mp.prec) * y_0[i]
81
+ f_0.append(f_0_n)
82
+
83
+ f_1 = [y_0[i] + f_0[i]*h/2 for i in range(1, a)]
84
+ for i in range(a):
85
+ f_1_n += sympify(DMFsubs(red[i], A + h/2, mpm=True))._to_mpmath(mp.prec) * (y_0[i] + f_0[i]*h/2)
86
+ f_1.append(f_1_n)
87
+
88
+ f_2 = [y_0[i] + f_1[i]*h/2 for i in range(1, a)]
89
+ for i in range(a):
90
+ f_2_n += sympify(DMFsubs(red[i], A + h/2, mpm=True))._to_mpmath(mp.prec) * (y_0[i] + f_1[i]*h/2)
91
+ f_2.append(f_2_n)
92
+
93
+ f_3 = [y_0[i] + f_2[i]*h for i in range(1, a)]
94
+ for i in range(a):
95
+ f_3_n += sympify(DMFsubs(red[i], A + h, mpm=True))._to_mpmath(mp.prec) * (y_0[i] + f_2[i]*h)
96
+ f_3.append(f_3_n)
97
+
98
+ return [y_0[i] + h*(f_0[i]+2*f_1[i]+2*f_2[i]+f_3[i])/6 for i in range(a)]
.venv/lib/python3.12/site-packages/sympy/holonomic/recurrence.py ADDED
@@ -0,0 +1,342 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ """Recurrence Operators"""
2
+
3
+ from sympy.core.singleton import S
4
+ from sympy.core.symbol import (Symbol, symbols)
5
+ from sympy.printing import sstr
6
+ from sympy.core.sympify import sympify
7
+
8
+
9
+ def RecurrenceOperators(base, generator):
10
+ """
11
+ Returns an Algebra of Recurrence Operators and the operator for
12
+ shifting i.e. the `Sn` operator.
13
+ The first argument needs to be the base polynomial ring for the algebra
14
+ and the second argument must be a generator which can be either a
15
+ noncommutative Symbol or a string.
16
+
17
+ Examples
18
+ ========
19
+
20
+ >>> from sympy import ZZ
21
+ >>> from sympy import symbols
22
+ >>> from sympy.holonomic.recurrence import RecurrenceOperators
23
+ >>> n = symbols('n', integer=True)
24
+ >>> R, Sn = RecurrenceOperators(ZZ.old_poly_ring(n), 'Sn')
25
+ """
26
+
27
+ ring = RecurrenceOperatorAlgebra(base, generator)
28
+ return (ring, ring.shift_operator)
29
+
30
+
31
+ class RecurrenceOperatorAlgebra:
32
+ """
33
+ A Recurrence Operator Algebra is a set of noncommutative polynomials
34
+ in intermediate `Sn` and coefficients in a base ring A. It follows the
35
+ commutation rule:
36
+ Sn * a(n) = a(n + 1) * Sn
37
+
38
+ This class represents a Recurrence Operator Algebra and serves as the parent ring
39
+ for Recurrence Operators.
40
+
41
+ Examples
42
+ ========
43
+
44
+ >>> from sympy import ZZ
45
+ >>> from sympy import symbols
46
+ >>> from sympy.holonomic.recurrence import RecurrenceOperators
47
+ >>> n = symbols('n', integer=True)
48
+ >>> R, Sn = RecurrenceOperators(ZZ.old_poly_ring(n), 'Sn')
49
+ >>> R
50
+ Univariate Recurrence Operator Algebra in intermediate Sn over the base ring
51
+ ZZ[n]
52
+
53
+ See Also
54
+ ========
55
+
56
+ RecurrenceOperator
57
+ """
58
+
59
+ def __init__(self, base, generator):
60
+ # the base ring for the algebra
61
+ self.base = base
62
+ # the operator representing shift i.e. `Sn`
63
+ self.shift_operator = RecurrenceOperator(
64
+ [base.zero, base.one], self)
65
+
66
+ if generator is None:
67
+ self.gen_symbol = symbols('Sn', commutative=False)
68
+ else:
69
+ if isinstance(generator, str):
70
+ self.gen_symbol = symbols(generator, commutative=False)
71
+ elif isinstance(generator, Symbol):
72
+ self.gen_symbol = generator
73
+
74
+ def __str__(self):
75
+ string = 'Univariate Recurrence Operator Algebra in intermediate '\
76
+ + sstr(self.gen_symbol) + ' over the base ring ' + \
77
+ (self.base).__str__()
78
+
79
+ return string
80
+
81
+ __repr__ = __str__
82
+
83
+ def __eq__(self, other):
84
+ if self.base == other.base and self.gen_symbol == other.gen_symbol:
85
+ return True
86
+ else:
87
+ return False
88
+
89
+
90
+ def _add_lists(list1, list2):
91
+ if len(list1) <= len(list2):
92
+ sol = [a + b for a, b in zip(list1, list2)] + list2[len(list1):]
93
+ else:
94
+ sol = [a + b for a, b in zip(list1, list2)] + list1[len(list2):]
95
+ return sol
96
+
97
+
98
+ class RecurrenceOperator:
99
+ """
100
+ The Recurrence Operators are defined by a list of polynomials
101
+ in the base ring and the parent ring of the Operator.
102
+
103
+ Explanation
104
+ ===========
105
+
106
+ Takes a list of polynomials for each power of Sn and the
107
+ parent ring which must be an instance of RecurrenceOperatorAlgebra.
108
+
109
+ A Recurrence Operator can be created easily using
110
+ the operator `Sn`. See examples below.
111
+
112
+ Examples
113
+ ========
114
+
115
+ >>> from sympy.holonomic.recurrence import RecurrenceOperator, RecurrenceOperators
116
+ >>> from sympy import ZZ
117
+ >>> from sympy import symbols
118
+ >>> n = symbols('n', integer=True)
119
+ >>> R, Sn = RecurrenceOperators(ZZ.old_poly_ring(n),'Sn')
120
+
121
+ >>> RecurrenceOperator([0, 1, n**2], R)
122
+ (1)Sn + (n**2)Sn**2
123
+
124
+ >>> Sn*n
125
+ (n + 1)Sn
126
+
127
+ >>> n*Sn*n + 1 - Sn**2*n
128
+ (1) + (n**2 + n)Sn + (-n - 2)Sn**2
129
+
130
+ See Also
131
+ ========
132
+
133
+ DifferentialOperatorAlgebra
134
+ """
135
+
136
+ _op_priority = 20
137
+
138
+ def __init__(self, list_of_poly, parent):
139
+ # the parent ring for this operator
140
+ # must be an RecurrenceOperatorAlgebra object
141
+ self.parent = parent
142
+ # sequence of polynomials in n for each power of Sn
143
+ # represents the operator
144
+ # convert the expressions into ring elements using from_sympy
145
+ if isinstance(list_of_poly, list):
146
+ for i, j in enumerate(list_of_poly):
147
+ if isinstance(j, int):
148
+ list_of_poly[i] = self.parent.base.from_sympy(S(j))
149
+ elif not isinstance(j, self.parent.base.dtype):
150
+ list_of_poly[i] = self.parent.base.from_sympy(j)
151
+
152
+ self.listofpoly = list_of_poly
153
+ self.order = len(self.listofpoly) - 1
154
+
155
+ def __mul__(self, other):
156
+ """
157
+ Multiplies two Operators and returns another
158
+ RecurrenceOperator instance using the commutation rule
159
+ Sn * a(n) = a(n + 1) * Sn
160
+ """
161
+
162
+ listofself = self.listofpoly
163
+ base = self.parent.base
164
+
165
+ if not isinstance(other, RecurrenceOperator):
166
+ if not isinstance(other, self.parent.base.dtype):
167
+ listofother = [self.parent.base.from_sympy(sympify(other))]
168
+
169
+ else:
170
+ listofother = [other]
171
+ else:
172
+ listofother = other.listofpoly
173
+ # multiply a polynomial `b` with a list of polynomials
174
+
175
+ def _mul_dmp_diffop(b, listofother):
176
+ if isinstance(listofother, list):
177
+ return [i * b for i in listofother]
178
+ return [b * listofother]
179
+
180
+ sol = _mul_dmp_diffop(listofself[0], listofother)
181
+
182
+ # compute Sn^i * b
183
+ def _mul_Sni_b(b):
184
+ sol = [base.zero]
185
+
186
+ if isinstance(b, list):
187
+ for i in b:
188
+ j = base.to_sympy(i).subs(base.gens[0], base.gens[0] + S.One)
189
+ sol.append(base.from_sympy(j))
190
+
191
+ else:
192
+ j = b.subs(base.gens[0], base.gens[0] + S.One)
193
+ sol.append(base.from_sympy(j))
194
+
195
+ return sol
196
+
197
+ for i in range(1, len(listofself)):
198
+ # find Sn^i * b in ith iteration
199
+ listofother = _mul_Sni_b(listofother)
200
+ # solution = solution + listofself[i] * (Sn^i * b)
201
+ sol = _add_lists(sol, _mul_dmp_diffop(listofself[i], listofother))
202
+
203
+ return RecurrenceOperator(sol, self.parent)
204
+
205
+ def __rmul__(self, other):
206
+ if not isinstance(other, RecurrenceOperator):
207
+
208
+ if isinstance(other, int):
209
+ other = S(other)
210
+
211
+ if not isinstance(other, self.parent.base.dtype):
212
+ other = (self.parent.base).from_sympy(other)
213
+
214
+ sol = [other * j for j in self.listofpoly]
215
+ return RecurrenceOperator(sol, self.parent)
216
+
217
+ def __add__(self, other):
218
+ if isinstance(other, RecurrenceOperator):
219
+
220
+ sol = _add_lists(self.listofpoly, other.listofpoly)
221
+ return RecurrenceOperator(sol, self.parent)
222
+
223
+ else:
224
+
225
+ if isinstance(other, int):
226
+ other = S(other)
227
+ list_self = self.listofpoly
228
+ if not isinstance(other, self.parent.base.dtype):
229
+ list_other = [((self.parent).base).from_sympy(other)]
230
+ else:
231
+ list_other = [other]
232
+ sol = [list_self[0] + list_other[0]] + list_self[1:]
233
+
234
+ return RecurrenceOperator(sol, self.parent)
235
+
236
+ __radd__ = __add__
237
+
238
+ def __sub__(self, other):
239
+ return self + (-1) * other
240
+
241
+ def __rsub__(self, other):
242
+ return (-1) * self + other
243
+
244
+ def __pow__(self, n):
245
+ if n == 1:
246
+ return self
247
+ result = RecurrenceOperator([self.parent.base.one], self.parent)
248
+ if n == 0:
249
+ return result
250
+ # if self is `Sn`
251
+ if self.listofpoly == self.parent.shift_operator.listofpoly:
252
+ sol = [self.parent.base.zero] * n + [self.parent.base.one]
253
+ return RecurrenceOperator(sol, self.parent)
254
+ x = self
255
+ while True:
256
+ if n % 2:
257
+ result *= x
258
+ n >>= 1
259
+ if not n:
260
+ break
261
+ x *= x
262
+ return result
263
+
264
+ def __str__(self):
265
+ listofpoly = self.listofpoly
266
+ print_str = ''
267
+
268
+ for i, j in enumerate(listofpoly):
269
+ if j == self.parent.base.zero:
270
+ continue
271
+
272
+ j = self.parent.base.to_sympy(j)
273
+
274
+ if i == 0:
275
+ print_str += '(' + sstr(j) + ')'
276
+ continue
277
+
278
+ if print_str:
279
+ print_str += ' + '
280
+
281
+ if i == 1:
282
+ print_str += '(' + sstr(j) + ')Sn'
283
+ continue
284
+
285
+ print_str += '(' + sstr(j) + ')' + 'Sn**' + sstr(i)
286
+
287
+ return print_str
288
+
289
+ __repr__ = __str__
290
+
291
+ def __eq__(self, other):
292
+ if isinstance(other, RecurrenceOperator):
293
+ if self.listofpoly == other.listofpoly and self.parent == other.parent:
294
+ return True
295
+ else:
296
+ return False
297
+ return self.listofpoly[0] == other and \
298
+ all(i is self.parent.base.zero for i in self.listofpoly[1:])
299
+
300
+
301
+ class HolonomicSequence:
302
+ """
303
+ A Holonomic Sequence is a type of sequence satisfying a linear homogeneous
304
+ recurrence relation with Polynomial coefficients. Alternatively, A sequence
305
+ is Holonomic if and only if its generating function is a Holonomic Function.
306
+ """
307
+
308
+ def __init__(self, recurrence, u0=[]):
309
+ self.recurrence = recurrence
310
+ if not isinstance(u0, list):
311
+ self.u0 = [u0]
312
+ else:
313
+ self.u0 = u0
314
+
315
+ if len(self.u0) == 0:
316
+ self._have_init_cond = False
317
+ else:
318
+ self._have_init_cond = True
319
+ self.n = recurrence.parent.base.gens[0]
320
+
321
+ def __repr__(self):
322
+ str_sol = 'HolonomicSequence(%s, %s)' % ((self.recurrence).__repr__(), sstr(self.n))
323
+ if not self._have_init_cond:
324
+ return str_sol
325
+ else:
326
+ cond_str = ''
327
+ seq_str = 0
328
+ for i in self.u0:
329
+ cond_str += ', u(%s) = %s' % (sstr(seq_str), sstr(i))
330
+ seq_str += 1
331
+
332
+ sol = str_sol + cond_str
333
+ return sol
334
+
335
+ __str__ = __repr__
336
+
337
+ def __eq__(self, other):
338
+ if self.recurrence != other.recurrence or self.n != other.n:
339
+ return False
340
+ if self._have_init_cond and other._have_init_cond:
341
+ return self.u0 == other.u0
342
+ return True
.venv/lib/python3.12/site-packages/sympy/holonomic/tests/__init__.py ADDED
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1
+ from sympy.holonomic import (DifferentialOperator, HolonomicFunction,
2
+ DifferentialOperators, from_hyper,
3
+ from_meijerg, expr_to_holonomic)
4
+ from sympy.holonomic.recurrence import RecurrenceOperators, HolonomicSequence
5
+ from sympy.core import EulerGamma
6
+ from sympy.core.numbers import (I, Rational, pi)
7
+ from sympy.core.singleton import S
8
+ from sympy.core.symbol import (Symbol, symbols)
9
+ from sympy.functions.elementary.exponential import (exp, log)
10
+ from sympy.functions.elementary.hyperbolic import (asinh, cosh)
11
+ from sympy.functions.elementary.miscellaneous import sqrt
12
+ from sympy.functions.elementary.trigonometric import (cos, sin)
13
+ from sympy.functions.special.bessel import besselj
14
+ from sympy.functions.special.beta_functions import beta
15
+ from sympy.functions.special.error_functions import (Ci, Si, erf, erfc)
16
+ from sympy.functions.special.gamma_functions import gamma
17
+ from sympy.functions.special.hyper import (hyper, meijerg)
18
+ from sympy.printing.str import sstr
19
+ from sympy.series.order import O
20
+ from sympy.simplify.hyperexpand import hyperexpand
21
+ from sympy.polys.domains.integerring import ZZ
22
+ from sympy.polys.domains.rationalfield import QQ
23
+ from sympy.polys.domains.realfield import RR
24
+
25
+
26
+ def test_DifferentialOperator():
27
+ x = symbols('x')
28
+ R, Dx = DifferentialOperators(QQ.old_poly_ring(x), 'Dx')
29
+ assert Dx == R.derivative_operator
30
+ assert Dx == DifferentialOperator([R.base.zero, R.base.one], R)
31
+ assert x * Dx + x**2 * Dx**2 == DifferentialOperator([0, x, x**2], R)
32
+ assert (x**2 + 1) + Dx + x * \
33
+ Dx**5 == DifferentialOperator([x**2 + 1, 1, 0, 0, 0, x], R)
34
+ assert (x * Dx + x**2 + 1 - Dx * (x**3 + x))**3 == (-48 * x**6) + \
35
+ (-57 * x**7) * Dx + (-15 * x**8) * Dx**2 + (-x**9) * Dx**3
36
+ p = (x * Dx**2 + (x**2 + 3) * Dx**5) * (Dx + x**2)
37
+ q = (2 * x) + (4 * x**2) * Dx + (x**3) * Dx**2 + \
38
+ (20 * x**2 + x + 60) * Dx**3 + (10 * x**3 + 30 * x) * Dx**4 + \
39
+ (x**4 + 3 * x**2) * Dx**5 + (x**2 + 3) * Dx**6
40
+ assert p == q
41
+
42
+
43
+ def test_HolonomicFunction_addition():
44
+ x = symbols('x')
45
+ R, Dx = DifferentialOperators(ZZ.old_poly_ring(x), 'Dx')
46
+ p = HolonomicFunction(Dx**2 * x, x)
47
+ q = HolonomicFunction((2) * Dx + (x) * Dx**2, x)
48
+ assert p == q
49
+ p = HolonomicFunction(x * Dx + 1, x)
50
+ q = HolonomicFunction(Dx + 1, x)
51
+ r = HolonomicFunction((x - 2) + (x**2 - 2) * Dx + (x**2 - x) * Dx**2, x)
52
+ assert p + q == r
53
+ p = HolonomicFunction(x * Dx + Dx**2 * (x**2 + 2), x)
54
+ q = HolonomicFunction(Dx - 3, x)
55
+ r = HolonomicFunction((-54 * x**2 - 126 * x - 150) + (-135 * x**3 - 252 * x**2 - 270 * x + 140) * Dx +\
56
+ (-27 * x**4 - 24 * x**2 + 14 * x - 150) * Dx**2 + \
57
+ (9 * x**4 + 15 * x**3 + 38 * x**2 + 30 * x +40) * Dx**3, x)
58
+ assert p + q == r
59
+ p = HolonomicFunction(Dx**5 - 1, x)
60
+ q = HolonomicFunction(x**3 + Dx, x)
61
+ r = HolonomicFunction((-x**18 + 45*x**14 - 525*x**10 + 1575*x**6 - x**3 - 630*x**2) + \
62
+ (-x**15 + 30*x**11 - 195*x**7 + 210*x**3 - 1)*Dx + (x**18 - 45*x**14 + 525*x**10 - \
63
+ 1575*x**6 + x**3 + 630*x**2)*Dx**5 + (x**15 - 30*x**11 + 195*x**7 - 210*x**3 + \
64
+ 1)*Dx**6, x)
65
+ assert p+q == r
66
+
67
+ p = x**2 + 3*x + 8
68
+ q = x**3 - 7*x + 5
69
+ p = p*Dx - p.diff()
70
+ q = q*Dx - q.diff()
71
+ r = HolonomicFunction(p, x) + HolonomicFunction(q, x)
72
+ s = HolonomicFunction((6*x**2 + 18*x + 14) + (-4*x**3 - 18*x**2 - 62*x + 10)*Dx +\
73
+ (x**4 + 6*x**3 + 31*x**2 - 10*x - 71)*Dx**2, x)
74
+ assert r == s
75
+
76
+
77
+ def test_HolonomicFunction_multiplication():
78
+ x = symbols('x')
79
+ R, Dx = DifferentialOperators(ZZ.old_poly_ring(x), 'Dx')
80
+ p = HolonomicFunction(Dx+x+x*Dx**2, x)
81
+ q = HolonomicFunction(x*Dx+Dx*x+Dx**2, x)
82
+ r = HolonomicFunction((8*x**6 + 4*x**4 + 6*x**2 + 3) + (24*x**5 - 4*x**3 + 24*x)*Dx + \
83
+ (8*x**6 + 20*x**4 + 12*x**2 + 2)*Dx**2 + (8*x**5 + 4*x**3 + 4*x)*Dx**3 + \
84
+ (2*x**4 + x**2)*Dx**4, x)
85
+ assert p*q == r
86
+ p = HolonomicFunction(Dx**2+1, x)
87
+ q = HolonomicFunction(Dx-1, x)
88
+ r = HolonomicFunction((2) + (-2)*Dx + (1)*Dx**2, x)
89
+ assert p*q == r
90
+ p = HolonomicFunction(Dx**2+1+x+Dx, x)
91
+ q = HolonomicFunction((Dx*x-1)**2, x)
92
+ r = HolonomicFunction((4*x**7 + 11*x**6 + 16*x**5 + 4*x**4 - 6*x**3 - 7*x**2 - 8*x - 2) + \
93
+ (8*x**6 + 26*x**5 + 24*x**4 - 3*x**3 - 11*x**2 - 6*x - 2)*Dx + \
94
+ (8*x**6 + 18*x**5 + 15*x**4 - 3*x**3 - 6*x**2 - 6*x - 2)*Dx**2 + (8*x**5 + \
95
+ 10*x**4 + 6*x**3 - 2*x**2 - 4*x)*Dx**3 + (4*x**5 + 3*x**4 - x**2)*Dx**4, x)
96
+ assert p*q == r
97
+ p = HolonomicFunction(x*Dx**2-1, x)
98
+ q = HolonomicFunction(Dx*x-x, x)
99
+ r = HolonomicFunction((x - 3) + (-2*x + 2)*Dx + (x)*Dx**2, x)
100
+ assert p*q == r
101
+
102
+
103
+ def test_HolonomicFunction_power():
104
+ x = symbols('x')
105
+ R, Dx = DifferentialOperators(ZZ.old_poly_ring(x), 'Dx')
106
+ p = HolonomicFunction(Dx+x+x*Dx**2, x)
107
+ a = HolonomicFunction(Dx, x)
108
+ for n in range(10):
109
+ assert a == p**n
110
+ a *= p
111
+
112
+
113
+ def test_addition_initial_condition():
114
+ x = symbols('x')
115
+ R, Dx = DifferentialOperators(QQ.old_poly_ring(x), 'Dx')
116
+ p = HolonomicFunction(Dx-1, x, 0, [3])
117
+ q = HolonomicFunction(Dx**2+1, x, 0, [1, 0])
118
+ r = HolonomicFunction(-1 + Dx - Dx**2 + Dx**3, x, 0, [4, 3, 2])
119
+ assert p + q == r
120
+ p = HolonomicFunction(Dx - x + Dx**2, x, 0, [1, 2])
121
+ q = HolonomicFunction(Dx**2 + x, x, 0, [1, 0])
122
+ r = HolonomicFunction((-x**4 - x**3/4 - x**2 + Rational(1, 4)) + (x**3 + x**2/4 + x*Rational(3, 4) + 1)*Dx + \
123
+ (x*Rational(-3, 2) + Rational(7, 4))*Dx**2 + (x**2 - x*Rational(7, 4) + Rational(1, 4))*Dx**3 + (x**2 + x/4 + S.Half)*Dx**4, x, 0, [2, 2, -2, 2])
124
+ assert p + q == r
125
+ p = HolonomicFunction(Dx**2 + 4*x*Dx + x**2, x, 0, [3, 4])
126
+ q = HolonomicFunction(Dx**2 + 1, x, 0, [1, 1])
127
+ r = HolonomicFunction((x**6 + 2*x**4 - 5*x**2 - 6) + (4*x**5 + 36*x**3 - 32*x)*Dx + \
128
+ (x**6 + 3*x**4 + 5*x**2 - 9)*Dx**2 + (4*x**5 + 36*x**3 - 32*x)*Dx**3 + (x**4 + \
129
+ 10*x**2 - 3)*Dx**4, x, 0, [4, 5, -1, -17])
130
+ assert p + q == r
131
+ q = HolonomicFunction(Dx**3 + x, x, 2, [3, 0, 1])
132
+ p = HolonomicFunction(Dx - 1, x, 2, [1])
133
+ r = HolonomicFunction((-x**2 - x + 1) + (x**2 + x)*Dx + (-x - 2)*Dx**3 + \
134
+ (x + 1)*Dx**4, x, 2, [4, 1, 2, -5 ])
135
+ assert p + q == r
136
+ p = expr_to_holonomic(sin(x))
137
+ q = expr_to_holonomic(1/x, x0=1)
138
+ r = HolonomicFunction((x**2 + 6) + (x**3 + 2*x)*Dx + (x**2 + 6)*Dx**2 + (x**3 + 2*x)*Dx**3, \
139
+ x, 1, [sin(1) + 1, -1 + cos(1), -sin(1) + 2])
140
+ assert p + q == r
141
+ C_1 = symbols('C_1')
142
+ p = expr_to_holonomic(sqrt(x))
143
+ q = expr_to_holonomic(sqrt(x**2-x))
144
+ r = (p + q).to_expr().subs(C_1, -I/2).expand()
145
+ assert r == I*sqrt(x)*sqrt(-x + 1) + sqrt(x)
146
+
147
+
148
+ def test_multiplication_initial_condition():
149
+ x = symbols('x')
150
+ R, Dx = DifferentialOperators(QQ.old_poly_ring(x), 'Dx')
151
+ p = HolonomicFunction(Dx**2 + x*Dx - 1, x, 0, [3, 1])
152
+ q = HolonomicFunction(Dx**2 + 1, x, 0, [1, 1])
153
+ r = HolonomicFunction((x**4 + 14*x**2 + 60) + 4*x*Dx + (x**4 + 9*x**2 + 20)*Dx**2 + \
154
+ (2*x**3 + 18*x)*Dx**3 + (x**2 + 10)*Dx**4, x, 0, [3, 4, 2, 3])
155
+ assert p * q == r
156
+ p = HolonomicFunction(Dx**2 + x, x, 0, [1, 0])
157
+ q = HolonomicFunction(Dx**3 - x**2, x, 0, [3, 3, 3])
158
+ r = HolonomicFunction((x**8 - 37*x**7/27 - 10*x**6/27 - 164*x**5/9 - 184*x**4/9 + \
159
+ 160*x**3/27 + 404*x**2/9 + 8*x + Rational(40, 3)) + (6*x**7 - 128*x**6/9 - 98*x**5/9 - 28*x**4/9 + \
160
+ 8*x**3/9 + 28*x**2 + x*Rational(40, 9) - 40)*Dx + (3*x**6 - 82*x**5/9 + 76*x**4/9 + 4*x**3/3 + \
161
+ 220*x**2/9 - x*Rational(80, 3))*Dx**2 + (-2*x**6 + 128*x**5/27 - 2*x**4/3 -80*x**2/9 + Rational(200, 9))*Dx**3 + \
162
+ (3*x**5 - 64*x**4/9 - 28*x**3/9 + 6*x**2 - x*Rational(20, 9) - Rational(20, 3))*Dx**4 + (-4*x**3 + 64*x**2/9 + \
163
+ x*Rational(8, 3))*Dx**5 + (x**4 - 64*x**3/27 - 4*x**2/3 + Rational(20, 9))*Dx**6, x, 0, [3, 3, 3, -3, -12, -24])
164
+ assert p * q == r
165
+ p = HolonomicFunction(Dx - 1, x, 0, [2])
166
+ q = HolonomicFunction(Dx**2 + 1, x, 0, [0, 1])
167
+ r = HolonomicFunction(2 -2*Dx + Dx**2, x, 0, [0, 2])
168
+ assert p * q == r
169
+ q = HolonomicFunction(x*Dx**2 + 1 + 2*Dx, x, 0,[0, 1])
170
+ r = HolonomicFunction((x - 1) + (-2*x + 2)*Dx + x*Dx**2, x, 0, [0, 2])
171
+ assert p * q == r
172
+ p = HolonomicFunction(Dx**2 - 1, x, 0, [1, 3])
173
+ q = HolonomicFunction(Dx**3 + 1, x, 0, [1, 2, 1])
174
+ r = HolonomicFunction(6*Dx + 3*Dx**2 + 2*Dx**3 - 3*Dx**4 + Dx**6, x, 0, [1, 5, 14, 17, 17, 2])
175
+ assert p * q == r
176
+ p = expr_to_holonomic(sin(x))
177
+ q = expr_to_holonomic(1/x, x0=1)
178
+ r = HolonomicFunction(x + 2*Dx + x*Dx**2, x, 1, [sin(1), -sin(1) + cos(1)])
179
+ assert p * q == r
180
+ p = expr_to_holonomic(sqrt(x))
181
+ q = expr_to_holonomic(sqrt(x**2-x))
182
+ r = (p * q).to_expr()
183
+ assert r == I*x*sqrt(-x + 1)
184
+
185
+
186
+ def test_HolonomicFunction_composition():
187
+ x = symbols('x')
188
+ R, Dx = DifferentialOperators(ZZ.old_poly_ring(x), 'Dx')
189
+ p = HolonomicFunction(Dx-1, x).composition(x**2+x)
190
+ r = HolonomicFunction((-2*x - 1) + Dx, x)
191
+ assert p == r
192
+ p = HolonomicFunction(Dx**2+1, x).composition(x**5+x**2+1)
193
+ r = HolonomicFunction((125*x**12 + 150*x**9 + 60*x**6 + 8*x**3) + (-20*x**3 - 2)*Dx + \
194
+ (5*x**4 + 2*x)*Dx**2, x)
195
+ assert p == r
196
+ p = HolonomicFunction(Dx**2*x+x, x).composition(2*x**3+x**2+1)
197
+ r = HolonomicFunction((216*x**9 + 324*x**8 + 180*x**7 + 152*x**6 + 112*x**5 + \
198
+ 36*x**4 + 4*x**3) + (24*x**4 + 16*x**3 + 3*x**2 - 6*x - 1)*Dx + (6*x**5 + 5*x**4 + \
199
+ x**3 + 3*x**2 + x)*Dx**2, x)
200
+ assert p == r
201
+ p = HolonomicFunction(Dx**2+1, x).composition(1-x**2)
202
+ r = HolonomicFunction((4*x**3) - Dx + x*Dx**2, x)
203
+ assert p == r
204
+ p = HolonomicFunction(Dx**2+1, x).composition(x - 2/(x**2 + 1))
205
+ r = HolonomicFunction((x**12 + 6*x**10 + 12*x**9 + 15*x**8 + 48*x**7 + 68*x**6 + \
206
+ 72*x**5 + 111*x**4 + 112*x**3 + 54*x**2 + 12*x + 1) + (12*x**8 + 32*x**6 + \
207
+ 24*x**4 - 4)*Dx + (x**12 + 6*x**10 + 4*x**9 + 15*x**8 + 16*x**7 + 20*x**6 + 24*x**5+ \
208
+ 15*x**4 + 16*x**3 + 6*x**2 + 4*x + 1)*Dx**2, x)
209
+ assert p == r
210
+
211
+
212
+ def test_from_hyper():
213
+ x = symbols('x')
214
+ R, Dx = DifferentialOperators(QQ.old_poly_ring(x), 'Dx')
215
+ p = hyper([1, 1], [Rational(3, 2)], x**2/4)
216
+ q = HolonomicFunction((4*x) + (5*x**2 - 8)*Dx + (x**3 - 4*x)*Dx**2, x, 1, [2*sqrt(3)*pi/9, -4*sqrt(3)*pi/27 + Rational(4, 3)])
217
+ r = from_hyper(p)
218
+ assert r == q
219
+ p = from_hyper(hyper([1], [Rational(3, 2)], x**2/4))
220
+ q = HolonomicFunction(-x + (-x**2/2 + 2)*Dx + x*Dx**2, x)
221
+ # x0 = 1
222
+ y0 = '[sqrt(pi)*exp(1/4)*erf(1/2), -sqrt(pi)*exp(1/4)*erf(1/2)/2 + 1]'
223
+ assert sstr(p.y0) == y0
224
+ assert q.annihilator == p.annihilator
225
+
226
+
227
+ def test_from_meijerg():
228
+ x = symbols('x')
229
+ R, Dx = DifferentialOperators(QQ.old_poly_ring(x), 'Dx')
230
+ p = from_meijerg(meijerg(([], [Rational(3, 2)]), ([S.Half], [S.Half, 1]), x))
231
+ q = HolonomicFunction(x/2 - Rational(1, 4) + (-x**2 + x/4)*Dx + x**2*Dx**2 + x**3*Dx**3, x, 1, \
232
+ [1/sqrt(pi), 1/(2*sqrt(pi)), -1/(4*sqrt(pi))])
233
+ assert p == q
234
+ p = from_meijerg(meijerg(([], []), ([0], []), x))
235
+ q = HolonomicFunction(1 + Dx, x, 0, [1])
236
+ assert p == q
237
+ p = from_meijerg(meijerg(([1], []), ([S.Half], [0]), x))
238
+ q = HolonomicFunction((x + S.Half)*Dx + x*Dx**2, x, 1, [sqrt(pi)*erf(1), exp(-1)])
239
+ assert p == q
240
+ p = from_meijerg(meijerg(([0], [1]), ([0], []), 2*x**2))
241
+ q = HolonomicFunction((3*x**2 - 1)*Dx + x**3*Dx**2, x, 1, [-exp(Rational(-1, 2)) + 1, -exp(Rational(-1, 2))])
242
+ assert p == q
243
+
244
+
245
+ def test_to_Sequence():
246
+ x = symbols('x')
247
+ R, Dx = DifferentialOperators(ZZ.old_poly_ring(x), 'Dx')
248
+ n = symbols('n', integer=True)
249
+ _, Sn = RecurrenceOperators(ZZ.old_poly_ring(n), 'Sn')
250
+ p = HolonomicFunction(x**2*Dx**4 + x + Dx, x).to_sequence()
251
+ q = [(HolonomicSequence(1 + (n + 2)*Sn**2 + (n**4 + 6*n**3 + 11*n**2 + 6*n)*Sn**3), 0, 1)]
252
+ assert p == q
253
+ p = HolonomicFunction(x**2*Dx**4 + x**3 + Dx**2, x).to_sequence()
254
+ q = [(HolonomicSequence(1 + (n**4 + 14*n**3 + 72*n**2 + 163*n + 140)*Sn**5), 0, 0)]
255
+ assert p == q
256
+ p = HolonomicFunction(x**3*Dx**4 + 1 + Dx**2, x).to_sequence()
257
+ q = [(HolonomicSequence(1 + (n**4 - 2*n**3 - n**2 + 2*n)*Sn + (n**2 + 3*n + 2)*Sn**2), 0, 0)]
258
+ assert p == q
259
+ p = HolonomicFunction(3*x**3*Dx**4 + 2*x*Dx + x*Dx**3, x).to_sequence()
260
+ q = [(HolonomicSequence(2*n + (3*n**4 - 6*n**3 - 3*n**2 + 6*n)*Sn + (n**3 + 3*n**2 + 2*n)*Sn**2), 0, 1)]
261
+ assert p == q
262
+
263
+
264
+ def test_to_Sequence_Initial_Coniditons():
265
+ x = symbols('x')
266
+ R, Dx = DifferentialOperators(QQ.old_poly_ring(x), 'Dx')
267
+ n = symbols('n', integer=True)
268
+ _, Sn = RecurrenceOperators(QQ.old_poly_ring(n), 'Sn')
269
+ p = HolonomicFunction(Dx - 1, x, 0, [1]).to_sequence()
270
+ q = [(HolonomicSequence(-1 + (n + 1)*Sn, 1), 0)]
271
+ assert p == q
272
+ p = HolonomicFunction(Dx**2 + 1, x, 0, [0, 1]).to_sequence()
273
+ q = [(HolonomicSequence(1 + (n**2 + 3*n + 2)*Sn**2, [0, 1]), 0)]
274
+ assert p == q
275
+ p = HolonomicFunction(Dx**2 + 1 + x**3*Dx, x, 0, [2, 3]).to_sequence()
276
+ q = [(HolonomicSequence(n + Sn**2 + (n**2 + 7*n + 12)*Sn**4, [2, 3, -1, Rational(-1, 2), Rational(1, 12)]), 1)]
277
+ assert p == q
278
+ p = HolonomicFunction(x**3*Dx**5 + 1 + Dx, x).to_sequence()
279
+ q = [(HolonomicSequence(1 + (n + 1)*Sn + (n**5 - 5*n**3 + 4*n)*Sn**2), 0, 3)]
280
+ assert p == q
281
+ C_0, C_1, C_2, C_3 = symbols('C_0, C_1, C_2, C_3')
282
+ p = expr_to_holonomic(log(1+x**2))
283
+ q = [(HolonomicSequence(n**2 + (n**2 + 2*n)*Sn**2, [0, 0, C_2]), 0, 1)]
284
+ assert p.to_sequence() == q
285
+ p = p.diff()
286
+ q = [(HolonomicSequence((n + 2) + (n + 2)*Sn**2, [C_0, 0]), 1, 0)]
287
+ assert p.to_sequence() == q
288
+ p = expr_to_holonomic(erf(x) + x).to_sequence()
289
+ q = [(HolonomicSequence((2*n**2 - 2*n) + (n**3 + 2*n**2 - n - 2)*Sn**2, [0, 1 + 2/sqrt(pi), 0, C_3]), 0, 2)]
290
+ assert p == q
291
+
292
+ def test_series():
293
+ x = symbols('x')
294
+ R, Dx = DifferentialOperators(ZZ.old_poly_ring(x), 'Dx')
295
+ p = HolonomicFunction(Dx**2 + 2*x*Dx, x, 0, [0, 1]).series(n=10)
296
+ q = x - x**3/3 + x**5/10 - x**7/42 + x**9/216 + O(x**10)
297
+ assert p == q
298
+ p = HolonomicFunction(Dx - 1, x).composition(x**2, 0, [1]) # e^(x**2)
299
+ q = HolonomicFunction(Dx**2 + 1, x, 0, [1, 0]) # cos(x)
300
+ r = (p * q).series(n=10) # expansion of cos(x) * exp(x**2)
301
+ s = 1 + x**2/2 + x**4/24 - 31*x**6/720 - 179*x**8/8064 + O(x**10)
302
+ assert r == s
303
+ t = HolonomicFunction((1 + x)*Dx**2 + Dx, x, 0, [0, 1]) # log(1 + x)
304
+ r = (p * t + q).series(n=10)
305
+ s = 1 + x - x**2 + 4*x**3/3 - 17*x**4/24 + 31*x**5/30 - 481*x**6/720 +\
306
+ 71*x**7/105 - 20159*x**8/40320 + 379*x**9/840 + O(x**10)
307
+ assert r == s
308
+ p = HolonomicFunction((6+6*x-3*x**2) - (10*x-3*x**2-3*x**3)*Dx + \
309
+ (4-6*x**3+2*x**4)*Dx**2, x, 0, [0, 1]).series(n=7)
310
+ q = x + x**3/6 - 3*x**4/16 + x**5/20 - 23*x**6/960 + O(x**7)
311
+ assert p == q
312
+ p = HolonomicFunction((6+6*x-3*x**2) - (10*x-3*x**2-3*x**3)*Dx + \
313
+ (4-6*x**3+2*x**4)*Dx**2, x, 0, [1, 0]).series(n=7)
314
+ q = 1 - 3*x**2/4 - x**3/4 - 5*x**4/32 - 3*x**5/40 - 17*x**6/384 + O(x**7)
315
+ assert p == q
316
+ p = expr_to_holonomic(erf(x) + x).series(n=10)
317
+ C_3 = symbols('C_3')
318
+ q = (erf(x) + x).series(n=10)
319
+ assert p.subs(C_3, -2/(3*sqrt(pi))) == q
320
+ assert expr_to_holonomic(sqrt(x**3 + x)).series(n=10) == sqrt(x**3 + x).series(n=10)
321
+ assert expr_to_holonomic((2*x - 3*x**2)**Rational(1, 3)).series() == ((2*x - 3*x**2)**Rational(1, 3)).series()
322
+ assert expr_to_holonomic(sqrt(x**2-x)).series() == (sqrt(x**2-x)).series()
323
+ assert expr_to_holonomic(cos(x)**2/x**2, y0={-2: [1, 0, -1]}).series(n=10) == (cos(x)**2/x**2).series(n=10)
324
+ assert expr_to_holonomic(cos(x)**2/x**2, x0=1).series(n=10).together() == (cos(x)**2/x**2).series(n=10, x0=1).together()
325
+ assert expr_to_holonomic(cos(x-1)**2/(x-1)**2, x0=1, y0={-2: [1, 0, -1]}).series(n=10) \
326
+ == (cos(x-1)**2/(x-1)**2).series(x0=1, n=10)
327
+
328
+ def test_evalf_euler():
329
+ x = symbols('x')
330
+ R, Dx = DifferentialOperators(QQ.old_poly_ring(x), 'Dx')
331
+
332
+ # log(1+x)
333
+ p = HolonomicFunction((1 + x)*Dx**2 + Dx, x, 0, [0, 1])
334
+
335
+ # path taken is a straight line from 0 to 1, on the real axis
336
+ r = [0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1]
337
+ s = '0.699525841805253' # approx. equal to log(2) i.e. 0.693147180559945
338
+ assert sstr(p.evalf(r, method='Euler')[-1]) == s
339
+
340
+ # path taken is a triangle 0-->1+i-->2
341
+ r = [0.1 + 0.1*I]
342
+ for i in range(9):
343
+ r.append(r[-1]+0.1+0.1*I)
344
+ for i in range(10):
345
+ r.append(r[-1]+0.1-0.1*I)
346
+
347
+ # close to the exact solution 1.09861228866811
348
+ # imaginary part also close to zero
349
+ s = '1.07530466271334 - 0.0251200594793912*I'
350
+ assert sstr(p.evalf(r, method='Euler')[-1]) == s
351
+
352
+ # sin(x)
353
+ p = HolonomicFunction(Dx**2 + 1, x, 0, [0, 1])
354
+ s = '0.905546532085401 - 6.93889390390723e-18*I'
355
+ assert sstr(p.evalf(r, method='Euler')[-1]) == s
356
+
357
+ # computing sin(pi/2) using this method
358
+ # using a linear path from 0 to pi/2
359
+ r = [0.1]
360
+ for i in range(14):
361
+ r.append(r[-1] + 0.1)
362
+ r.append(pi/2)
363
+ s = '1.08016557252834' # close to 1.0 (exact solution)
364
+ assert sstr(p.evalf(r, method='Euler')[-1]) == s
365
+
366
+ # trying different path, a rectangle (0-->i-->pi/2 + i-->pi/2)
367
+ # computing the same value sin(pi/2) using different path
368
+ r = [0.1*I]
369
+ for i in range(9):
370
+ r.append(r[-1]+0.1*I)
371
+ for i in range(15):
372
+ r.append(r[-1]+0.1)
373
+ r.append(pi/2+I)
374
+ for i in range(10):
375
+ r.append(r[-1]-0.1*I)
376
+
377
+ # close to 1.0
378
+ s = '0.976882381836257 - 1.65557671738537e-16*I'
379
+ assert sstr(p.evalf(r, method='Euler')[-1]) == s
380
+
381
+ # cos(x)
382
+ p = HolonomicFunction(Dx**2 + 1, x, 0, [1, 0])
383
+ # compute cos(pi) along 0-->pi
384
+ r = [0.05]
385
+ for i in range(61):
386
+ r.append(r[-1]+0.05)
387
+ r.append(pi)
388
+ # close to -1 (exact answer)
389
+ s = '-1.08140824719196'
390
+ assert sstr(p.evalf(r, method='Euler')[-1]) == s
391
+
392
+ # a rectangular path (0 -> i -> 2+i -> 2)
393
+ r = [0.1*I]
394
+ for i in range(9):
395
+ r.append(r[-1]+0.1*I)
396
+ for i in range(20):
397
+ r.append(r[-1]+0.1)
398
+ for i in range(10):
399
+ r.append(r[-1]-0.1*I)
400
+
401
+ p = HolonomicFunction(Dx**2 + 1, x, 0, [1,1]).evalf(r, method='Euler')
402
+ s = '0.501421652861245 - 3.88578058618805e-16*I'
403
+ assert sstr(p[-1]) == s
404
+
405
+ def test_evalf_rk4():
406
+ x = symbols('x')
407
+ R, Dx = DifferentialOperators(QQ.old_poly_ring(x), 'Dx')
408
+
409
+ # log(1+x)
410
+ p = HolonomicFunction((1 + x)*Dx**2 + Dx, x, 0, [0, 1])
411
+
412
+ # path taken is a straight line from 0 to 1, on the real axis
413
+ r = [0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1]
414
+ s = '0.693146363174626' # approx. equal to log(2) i.e. 0.693147180559945
415
+ assert sstr(p.evalf(r)[-1]) == s
416
+
417
+ # path taken is a triangle 0-->1+i-->2
418
+ r = [0.1 + 0.1*I]
419
+ for i in range(9):
420
+ r.append(r[-1]+0.1+0.1*I)
421
+ for i in range(10):
422
+ r.append(r[-1]+0.1-0.1*I)
423
+
424
+ # close to the exact solution 1.09861228866811
425
+ # imaginary part also close to zero
426
+ s = '1.098616 + 1.36083e-7*I'
427
+ assert sstr(p.evalf(r)[-1].n(7)) == s
428
+
429
+ # sin(x)
430
+ p = HolonomicFunction(Dx**2 + 1, x, 0, [0, 1])
431
+ s = '0.90929463522785 + 1.52655665885959e-16*I'
432
+ assert sstr(p.evalf(r)[-1]) == s
433
+
434
+ # computing sin(pi/2) using this method
435
+ # using a linear path from 0 to pi/2
436
+ r = [0.1]
437
+ for i in range(14):
438
+ r.append(r[-1] + 0.1)
439
+ r.append(pi/2)
440
+ s = '0.999999895088917' # close to 1.0 (exact solution)
441
+ assert sstr(p.evalf(r)[-1]) == s
442
+
443
+ # trying different path, a rectangle (0-->i-->pi/2 + i-->pi/2)
444
+ # computing the same value sin(pi/2) using different path
445
+ r = [0.1*I]
446
+ for i in range(9):
447
+ r.append(r[-1]+0.1*I)
448
+ for i in range(15):
449
+ r.append(r[-1]+0.1)
450
+ r.append(pi/2+I)
451
+ for i in range(10):
452
+ r.append(r[-1]-0.1*I)
453
+
454
+ # close to 1.0
455
+ s = '1.00000003415141 + 6.11940487991086e-16*I'
456
+ assert sstr(p.evalf(r)[-1]) == s
457
+
458
+ # cos(x)
459
+ p = HolonomicFunction(Dx**2 + 1, x, 0, [1, 0])
460
+ # compute cos(pi) along 0-->pi
461
+ r = [0.05]
462
+ for i in range(61):
463
+ r.append(r[-1]+0.05)
464
+ r.append(pi)
465
+ # close to -1 (exact answer)
466
+ s = '-0.999999993238714'
467
+ assert sstr(p.evalf(r)[-1]) == s
468
+
469
+ # a rectangular path (0 -> i -> 2+i -> 2)
470
+ r = [0.1*I]
471
+ for i in range(9):
472
+ r.append(r[-1]+0.1*I)
473
+ for i in range(20):
474
+ r.append(r[-1]+0.1)
475
+ for i in range(10):
476
+ r.append(r[-1]-0.1*I)
477
+
478
+ p = HolonomicFunction(Dx**2 + 1, x, 0, [1,1]).evalf(r)
479
+ s = '0.493152791638442 - 1.41553435639707e-15*I'
480
+ assert sstr(p[-1]) == s
481
+
482
+
483
+ def test_expr_to_holonomic():
484
+ x = symbols('x')
485
+ R, Dx = DifferentialOperators(QQ.old_poly_ring(x), 'Dx')
486
+ p = expr_to_holonomic((sin(x)/x)**2)
487
+ q = HolonomicFunction(8*x + (4*x**2 + 6)*Dx + 6*x*Dx**2 + x**2*Dx**3, x, 0, \
488
+ [1, 0, Rational(-2, 3)])
489
+ assert p == q
490
+ p = expr_to_holonomic(1/(1+x**2)**2)
491
+ q = HolonomicFunction(4*x + (x**2 + 1)*Dx, x, 0, [1])
492
+ assert p == q
493
+ p = expr_to_holonomic(exp(x)*sin(x)+x*log(1+x))
494
+ q = HolonomicFunction((2*x**3 + 10*x**2 + 20*x + 18) + (-2*x**4 - 10*x**3 - 20*x**2 \
495
+ - 18*x)*Dx + (2*x**5 + 6*x**4 + 7*x**3 + 8*x**2 + 10*x - 4)*Dx**2 + \
496
+ (-2*x**5 - 5*x**4 - 2*x**3 + 2*x**2 - x + 4)*Dx**3 + (x**5 + 2*x**4 - x**3 - \
497
+ 7*x**2/2 + x + Rational(5, 2))*Dx**4, x, 0, [0, 1, 4, -1])
498
+ assert p == q
499
+ p = expr_to_holonomic(x*exp(x)+cos(x)+1)
500
+ q = HolonomicFunction((-x - 3)*Dx + (x + 2)*Dx**2 + (-x - 3)*Dx**3 + (x + 2)*Dx**4, x, \
501
+ 0, [2, 1, 1, 3])
502
+ assert p == q
503
+ assert (x*exp(x)+cos(x)+1).series(n=10) == p.series(n=10)
504
+ p = expr_to_holonomic(log(1 + x)**2 + 1)
505
+ q = HolonomicFunction(Dx + (3*x + 3)*Dx**2 + (x**2 + 2*x + 1)*Dx**3, x, 0, [1, 0, 2])
506
+ assert p == q
507
+ p = expr_to_holonomic(erf(x)**2 + x)
508
+ q = HolonomicFunction((8*x**4 - 2*x**2 + 2)*Dx**2 + (6*x**3 - x/2)*Dx**3 + \
509
+ (x**2+ Rational(1, 4))*Dx**4, x, 0, [0, 1, 8/pi, 0])
510
+ assert p == q
511
+ p = expr_to_holonomic(cosh(x)*x)
512
+ q = HolonomicFunction((-x**2 + 2) -2*x*Dx + x**2*Dx**2, x, 0, [0, 1])
513
+ assert p == q
514
+ p = expr_to_holonomic(besselj(2, x))
515
+ q = HolonomicFunction((x**2 - 4) + x*Dx + x**2*Dx**2, x, 0, [0, 0])
516
+ assert p == q
517
+ p = expr_to_holonomic(besselj(0, x) + exp(x))
518
+ q = HolonomicFunction((-x**2 - x/2 + S.Half) + (x**2 - x/2 - Rational(3, 2))*Dx + (-x**2 + x/2 + 1)*Dx**2 +\
519
+ (x**2 + x/2)*Dx**3, x, 0, [2, 1, S.Half])
520
+ assert p == q
521
+ p = expr_to_holonomic(sin(x)**2/x)
522
+ q = HolonomicFunction(4 + 4*x*Dx + 3*Dx**2 + x*Dx**3, x, 0, [0, 1, 0])
523
+ assert p == q
524
+ p = expr_to_holonomic(sin(x)**2/x, x0=2)
525
+ q = HolonomicFunction((4) + (4*x)*Dx + (3)*Dx**2 + (x)*Dx**3, x, 2, [sin(2)**2/2,
526
+ sin(2)*cos(2) - sin(2)**2/4, -3*sin(2)**2/4 + cos(2)**2 - sin(2)*cos(2)])
527
+ assert p == q
528
+ p = expr_to_holonomic(log(x)/2 - Ci(2*x)/2 + Ci(2)/2)
529
+ q = HolonomicFunction(4*Dx + 4*x*Dx**2 + 3*Dx**3 + x*Dx**4, x, 0, \
530
+ [-log(2)/2 - EulerGamma/2 + Ci(2)/2, 0, 1, 0])
531
+ assert p == q
532
+ p = p.to_expr()
533
+ q = log(x)/2 - Ci(2*x)/2 + Ci(2)/2
534
+ assert p == q
535
+ p = expr_to_holonomic(x**S.Half, x0=1)
536
+ q = HolonomicFunction(x*Dx - S.Half, x, 1, [1])
537
+ assert p == q
538
+ p = expr_to_holonomic(sqrt(1 + x**2))
539
+ q = HolonomicFunction((-x) + (x**2 + 1)*Dx, x, 0, [1])
540
+ assert p == q
541
+ assert (expr_to_holonomic(sqrt(x) + sqrt(2*x)).to_expr()-\
542
+ (sqrt(x) + sqrt(2*x))).simplify() == 0
543
+ assert expr_to_holonomic(3*x+2*sqrt(x)).to_expr() == 3*x+2*sqrt(x)
544
+ p = expr_to_holonomic((x**4+x**3+5*x**2+3*x+2)/x**2, lenics=3)
545
+ q = HolonomicFunction((-2*x**4 - x**3 + 3*x + 4) + (x**5 + x**4 + 5*x**3 + 3*x**2 + \
546
+ 2*x)*Dx, x, 0, {-2: [2, 3, 5]})
547
+ assert p == q
548
+ p = expr_to_holonomic(1/(x-1)**2, lenics=3, x0=1)
549
+ q = HolonomicFunction((2) + (x - 1)*Dx, x, 1, {-2: [1, 0, 0]})
550
+ assert p == q
551
+ a = symbols("a")
552
+ p = expr_to_holonomic(sqrt(a*x), x=x)
553
+ assert p.to_expr() == sqrt(a)*sqrt(x)
554
+
555
+ def test_to_hyper():
556
+ x = symbols('x')
557
+ R, Dx = DifferentialOperators(QQ.old_poly_ring(x), 'Dx')
558
+ p = HolonomicFunction(Dx - 2, x, 0, [3]).to_hyper()
559
+ q = 3 * hyper([], [], 2*x)
560
+ assert p == q
561
+ p = hyperexpand(HolonomicFunction((1 + x) * Dx - 3, x, 0, [2]).to_hyper()).expand()
562
+ q = 2*x**3 + 6*x**2 + 6*x + 2
563
+ assert p == q
564
+ p = HolonomicFunction((1 + x)*Dx**2 + Dx, x, 0, [0, 1]).to_hyper()
565
+ q = -x**2*hyper((2, 2, 1), (3, 2), -x)/2 + x
566
+ assert p == q
567
+ p = HolonomicFunction(2*x*Dx + Dx**2, x, 0, [0, 2/sqrt(pi)]).to_hyper()
568
+ q = 2*x*hyper((S.Half,), (Rational(3, 2),), -x**2)/sqrt(pi)
569
+ assert p == q
570
+ p = hyperexpand(HolonomicFunction(2*x*Dx + Dx**2, x, 0, [1, -2/sqrt(pi)]).to_hyper())
571
+ q = erfc(x)
572
+ assert p.rewrite(erfc) == q
573
+ p = hyperexpand(HolonomicFunction((x**2 - 1) + x*Dx + x**2*Dx**2,
574
+ x, 0, [0, S.Half]).to_hyper())
575
+ q = besselj(1, x)
576
+ assert p == q
577
+ p = hyperexpand(HolonomicFunction(x*Dx**2 + Dx + x, x, 0, [1, 0]).to_hyper())
578
+ q = besselj(0, x)
579
+ assert p == q
580
+
581
+ def test_to_expr():
582
+ x = symbols('x')
583
+ R, Dx = DifferentialOperators(ZZ.old_poly_ring(x), 'Dx')
584
+ p = HolonomicFunction(Dx - 1, x, 0, [1]).to_expr()
585
+ q = exp(x)
586
+ assert p == q
587
+ p = HolonomicFunction(Dx**2 + 1, x, 0, [1, 0]).to_expr()
588
+ q = cos(x)
589
+ assert p == q
590
+ p = HolonomicFunction(Dx**2 - 1, x, 0, [1, 0]).to_expr()
591
+ q = cosh(x)
592
+ assert p == q
593
+ p = HolonomicFunction(2 + (4*x - 1)*Dx + \
594
+ (x**2 - x)*Dx**2, x, 0, [1, 2]).to_expr().expand()
595
+ q = 1/(x**2 - 2*x + 1)
596
+ assert p == q
597
+ p = expr_to_holonomic(sin(x)**2/x).integrate((x, 0, x)).to_expr()
598
+ q = (sin(x)**2/x).integrate((x, 0, x))
599
+ assert p == q
600
+ C_0, C_1, C_2, C_3 = symbols('C_0, C_1, C_2, C_3')
601
+ p = expr_to_holonomic(log(1+x**2)).to_expr()
602
+ q = C_2*log(x**2 + 1)
603
+ assert p == q
604
+ p = expr_to_holonomic(log(1+x**2)).diff().to_expr()
605
+ q = C_0*x/(x**2 + 1)
606
+ assert p == q
607
+ p = expr_to_holonomic(erf(x) + x).to_expr()
608
+ q = 3*C_3*x - 3*sqrt(pi)*C_3*erf(x)/2 + x + 2*x/sqrt(pi)
609
+ assert p == q
610
+ p = expr_to_holonomic(sqrt(x), x0=1).to_expr()
611
+ assert p == sqrt(x)
612
+ assert expr_to_holonomic(sqrt(x)).to_expr() == sqrt(x)
613
+ p = expr_to_holonomic(sqrt(1 + x**2)).to_expr()
614
+ assert p == sqrt(1+x**2)
615
+ p = expr_to_holonomic((2*x**2 + 1)**Rational(2, 3)).to_expr()
616
+ assert p == (2*x**2 + 1)**Rational(2, 3)
617
+ p = expr_to_holonomic(sqrt(-x**2+2*x)).to_expr()
618
+ assert p == sqrt(x)*sqrt(-x + 2)
619
+ p = expr_to_holonomic((-2*x**3+7*x)**Rational(2, 3)).to_expr()
620
+ q = x**Rational(2, 3)*(-2*x**2 + 7)**Rational(2, 3)
621
+ assert p == q
622
+ p = from_hyper(hyper((-2, -3), (S.Half, ), x))
623
+ s = hyperexpand(hyper((-2, -3), (S.Half, ), x))
624
+ D_0 = Symbol('D_0')
625
+ C_0 = Symbol('C_0')
626
+ assert (p.to_expr().subs({C_0:1, D_0:0}) - s).simplify() == 0
627
+ p.y0 = {0: [1], S.Half: [0]}
628
+ assert p.to_expr() == s
629
+ assert expr_to_holonomic(x**5).to_expr() == x**5
630
+ assert expr_to_holonomic(2*x**3-3*x**2).to_expr().expand() == \
631
+ 2*x**3-3*x**2
632
+ a = symbols("a")
633
+ p = (expr_to_holonomic(1.4*x)*expr_to_holonomic(a*x, x)).to_expr()
634
+ q = 1.4*a*x**2
635
+ assert p == q
636
+ p = (expr_to_holonomic(1.4*x)+expr_to_holonomic(a*x, x)).to_expr()
637
+ q = x*(a + 1.4)
638
+ assert p == q
639
+ p = (expr_to_holonomic(1.4*x)+expr_to_holonomic(x)).to_expr()
640
+ assert p == 2.4*x
641
+
642
+
643
+ def test_integrate():
644
+ x = symbols('x')
645
+ R, Dx = DifferentialOperators(ZZ.old_poly_ring(x), 'Dx')
646
+ p = expr_to_holonomic(sin(x)**2/x, x0=1).integrate((x, 2, 3))
647
+ q = '0.166270406994788'
648
+ assert sstr(p) == q
649
+ p = expr_to_holonomic(sin(x)).integrate((x, 0, x)).to_expr()
650
+ q = 1 - cos(x)
651
+ assert p == q
652
+ p = expr_to_holonomic(sin(x)).integrate((x, 0, 3))
653
+ q = 1 - cos(3)
654
+ assert p == q
655
+ p = expr_to_holonomic(sin(x)/x, x0=1).integrate((x, 1, 2))
656
+ q = '0.659329913368450'
657
+ assert sstr(p) == q
658
+ p = expr_to_holonomic(sin(x)**2/x, x0=1).integrate((x, 1, 0))
659
+ q = '-0.423690480850035'
660
+ assert sstr(p) == q
661
+ p = expr_to_holonomic(sin(x)/x)
662
+ assert p.integrate(x).to_expr() == Si(x)
663
+ assert p.integrate((x, 0, 2)) == Si(2)
664
+ p = expr_to_holonomic(sin(x)**2/x)
665
+ q = p.to_expr()
666
+ assert p.integrate(x).to_expr() == q.integrate((x, 0, x))
667
+ assert p.integrate((x, 0, 1)) == q.integrate((x, 0, 1))
668
+ assert expr_to_holonomic(1/x, x0=1).integrate(x).to_expr() == log(x)
669
+ p = expr_to_holonomic((x + 1)**3*exp(-x), x0=-1).integrate(x).to_expr()
670
+ q = (-x**3 - 6*x**2 - 15*x + 6*exp(x + 1) - 16)*exp(-x)
671
+ assert p == q
672
+ p = expr_to_holonomic(cos(x)**2/x**2, y0={-2: [1, 0, -1]}).integrate(x).to_expr()
673
+ q = -Si(2*x) - cos(x)**2/x
674
+ assert p == q
675
+ p = expr_to_holonomic(sqrt(x**2+x)).integrate(x).to_expr()
676
+ q = (x**Rational(3, 2)*(2*x**2 + 3*x + 1) - x*sqrt(x + 1)*asinh(sqrt(x)))/(4*x*sqrt(x + 1))
677
+ assert p == q
678
+ p = expr_to_holonomic(sqrt(x**2+1)).integrate(x).to_expr()
679
+ q = (sqrt(x**2+1)).integrate(x)
680
+ assert (p-q).simplify() == 0
681
+ p = expr_to_holonomic(1/x**2, y0={-2:[1, 0, 0]})
682
+ r = expr_to_holonomic(1/x**2, lenics=3)
683
+ assert p == r
684
+ q = expr_to_holonomic(cos(x)**2)
685
+ assert (r*q).integrate(x).to_expr() == -Si(2*x) - cos(x)**2/x
686
+
687
+
688
+ def test_diff():
689
+ x, y = symbols('x, y')
690
+ R, Dx = DifferentialOperators(ZZ.old_poly_ring(x), 'Dx')
691
+ p = HolonomicFunction(x*Dx**2 + 1, x, 0, [0, 1])
692
+ assert p.diff().to_expr() == p.to_expr().diff().simplify()
693
+ p = HolonomicFunction(Dx**2 - 1, x, 0, [1, 0])
694
+ assert p.diff(x, 2).to_expr() == p.to_expr()
695
+ p = expr_to_holonomic(Si(x))
696
+ assert p.diff().to_expr() == sin(x)/x
697
+ assert p.diff(y) == 0
698
+ C_0, C_1, C_2, C_3 = symbols('C_0, C_1, C_2, C_3')
699
+ q = Si(x)
700
+ assert p.diff(x).to_expr() == q.diff()
701
+ assert p.diff(x, 2).to_expr().subs(C_0, Rational(-1, 3)).cancel() == q.diff(x, 2).cancel()
702
+ assert p.diff(x, 3).series().subs({C_3: Rational(-1, 3), C_0: 0}) == q.diff(x, 3).series()
703
+
704
+
705
+ def test_extended_domain_in_expr_to_holonomic():
706
+ x = symbols('x')
707
+ p = expr_to_holonomic(1.2*cos(3.1*x))
708
+ assert p.to_expr() == 1.2*cos(3.1*x)
709
+ assert sstr(p.integrate(x).to_expr()) == '0.387096774193548*sin(3.1*x)'
710
+ _, Dx = DifferentialOperators(RR.old_poly_ring(x), 'Dx')
711
+ p = expr_to_holonomic(1.1329138213*x)
712
+ q = HolonomicFunction((-1.1329138213) + (1.1329138213*x)*Dx, x, 0, {1: [1.1329138213]})
713
+ assert p == q
714
+ assert p.to_expr() == 1.1329138213*x
715
+ assert sstr(p.integrate((x, 1, 2))) == sstr((1.1329138213*x).integrate((x, 1, 2)))
716
+ y, z = symbols('y, z')
717
+ p = expr_to_holonomic(sin(x*y*z), x=x)
718
+ assert p.to_expr() == sin(x*y*z)
719
+ assert p.integrate(x).to_expr() == (-cos(x*y*z) + 1)/(y*z)
720
+ p = expr_to_holonomic(sin(x*y + z), x=x).integrate(x).to_expr()
721
+ q = (cos(z) - cos(x*y + z))/y
722
+ assert p == q
723
+ a = symbols('a')
724
+ p = expr_to_holonomic(a*x, x)
725
+ assert p.to_expr() == a*x
726
+ assert p.integrate(x).to_expr() == a*x**2/2
727
+ D_2, C_1 = symbols("D_2, C_1")
728
+ p = expr_to_holonomic(x) + expr_to_holonomic(1.2*cos(x))
729
+ p = p.to_expr().subs(D_2, 0)
730
+ assert p - x - 1.2*cos(1.0*x) == 0
731
+ p = expr_to_holonomic(x) * expr_to_holonomic(1.2*cos(x))
732
+ p = p.to_expr().subs(C_1, 0)
733
+ assert p - 1.2*x*cos(1.0*x) == 0
734
+
735
+
736
+ def test_to_meijerg():
737
+ x = symbols('x')
738
+ assert hyperexpand(expr_to_holonomic(sin(x)).to_meijerg()) == sin(x)
739
+ assert hyperexpand(expr_to_holonomic(cos(x)).to_meijerg()) == cos(x)
740
+ assert hyperexpand(expr_to_holonomic(exp(x)).to_meijerg()) == exp(x)
741
+ assert hyperexpand(expr_to_holonomic(log(x)).to_meijerg()).simplify() == log(x)
742
+ assert expr_to_holonomic(4*x**2/3 + 7).to_meijerg() == 4*x**2/3 + 7
743
+ assert hyperexpand(expr_to_holonomic(besselj(2, x), lenics=3).to_meijerg()) == besselj(2, x)
744
+ p = hyper((Rational(-1, 2), -3), (), x)
745
+ assert from_hyper(p).to_meijerg() == hyperexpand(p)
746
+ p = hyper((S.One, S(3)), (S(2), ), x)
747
+ assert (hyperexpand(from_hyper(p).to_meijerg()) - hyperexpand(p)).expand() == 0
748
+ p = from_hyper(hyper((-2, -3), (S.Half, ), x))
749
+ s = hyperexpand(hyper((-2, -3), (S.Half, ), x))
750
+ C_0 = Symbol('C_0')
751
+ C_1 = Symbol('C_1')
752
+ D_0 = Symbol('D_0')
753
+ assert (hyperexpand(p.to_meijerg()).subs({C_0:1, D_0:0}) - s).simplify() == 0
754
+ p.y0 = {0: [1], S.Half: [0]}
755
+ assert (hyperexpand(p.to_meijerg()) - s).simplify() == 0
756
+ p = expr_to_holonomic(besselj(S.Half, x), initcond=False)
757
+ assert (p.to_expr() - (D_0*sin(x) + C_0*cos(x) + C_1*sin(x))/sqrt(x)).simplify() == 0
758
+ p = expr_to_holonomic(besselj(S.Half, x), y0={Rational(-1, 2): [sqrt(2)/sqrt(pi), sqrt(2)/sqrt(pi)]})
759
+ assert (p.to_expr() - besselj(S.Half, x) - besselj(Rational(-1, 2), x)).simplify() == 0
760
+
761
+
762
+ def test_gaussian():
763
+ mu, x = symbols("mu x")
764
+ sd = symbols("sd", positive=True)
765
+ Q = QQ[mu, sd].get_field()
766
+ e = sqrt(2)*exp(-(-mu + x)**2/(2*sd**2))/(2*sqrt(pi)*sd)
767
+ h1 = expr_to_holonomic(e, x, domain=Q)
768
+
769
+ _, Dx = DifferentialOperators(Q.old_poly_ring(x), 'Dx')
770
+ h2 = HolonomicFunction((-mu/sd**2 + x/sd**2) + (1)*Dx, x)
771
+
772
+ assert h1 == h2
773
+
774
+
775
+ def test_beta():
776
+ a, b, x = symbols("a b x", positive=True)
777
+ e = x**(a - 1)*(-x + 1)**(b - 1)/beta(a, b)
778
+ Q = QQ[a, b].get_field()
779
+ h1 = expr_to_holonomic(e, x, domain=Q)
780
+
781
+ _, Dx = DifferentialOperators(Q.old_poly_ring(x), 'Dx')
782
+ h2 = HolonomicFunction((a + x*(-a - b + 2) - 1) + (x**2 - x)*Dx, x)
783
+
784
+ assert h1 == h2
785
+
786
+
787
+ def test_gamma():
788
+ a, b, x = symbols("a b x", positive=True)
789
+ e = b**(-a)*x**(a - 1)*exp(-x/b)/gamma(a)
790
+ Q = QQ[a, b].get_field()
791
+ h1 = expr_to_holonomic(e, x, domain=Q)
792
+
793
+ _, Dx = DifferentialOperators(Q.old_poly_ring(x), 'Dx')
794
+ h2 = HolonomicFunction((-a + 1 + x/b) + (x)*Dx, x)
795
+
796
+ assert h1 == h2
797
+
798
+
799
+ def test_symbolic_power():
800
+ x, n = symbols("x n")
801
+ Q = QQ[n].get_field()
802
+ _, Dx = DifferentialOperators(Q.old_poly_ring(x), 'Dx')
803
+ h1 = HolonomicFunction((-1) + (x)*Dx, x) ** -n
804
+ h2 = HolonomicFunction((n) + (x)*Dx, x)
805
+
806
+ assert h1 == h2
807
+
808
+
809
+ def test_negative_power():
810
+ x = symbols("x")
811
+ _, Dx = DifferentialOperators(QQ.old_poly_ring(x), 'Dx')
812
+ h1 = HolonomicFunction((-1) + (x)*Dx, x) ** -2
813
+ h2 = HolonomicFunction((2) + (x)*Dx, x)
814
+
815
+ assert h1 == h2
816
+
817
+
818
+ def test_expr_in_power():
819
+ x, n = symbols("x n")
820
+ Q = QQ[n].get_field()
821
+ _, Dx = DifferentialOperators(Q.old_poly_ring(x), 'Dx')
822
+ h1 = HolonomicFunction((-1) + (x)*Dx, x) ** (n - 3)
823
+ h2 = HolonomicFunction((-n + 3) + (x)*Dx, x)
824
+
825
+ assert h1 == h2
826
+
827
+
828
+ def test_DifferentialOperatorEqPoly():
829
+ x = symbols('x', integer=True)
830
+ R, Dx = DifferentialOperators(QQ.old_poly_ring(x), 'Dx')
831
+ do = DifferentialOperator([x**2, R.base.zero, R.base.zero], R)
832
+ do2 = DifferentialOperator([x**2, 1, x], R)
833
+ assert not do == do2
834
+
835
+ # polynomial comparison issue, see https://github.com/sympy/sympy/pull/15799
836
+ # should work once that is solved
837
+ # p = do.listofpoly[0]
838
+ # assert do == p
839
+
840
+ p2 = do2.listofpoly[0]
841
+ assert not do2 == p2
842
+
843
+
844
+ def test_DifferentialOperatorPow():
845
+ x = symbols('x', integer=True)
846
+ R, _ = DifferentialOperators(QQ.old_poly_ring(x), 'Dx')
847
+ do = DifferentialOperator([x**2, R.base.zero, R.base.zero], R)
848
+ a = DifferentialOperator([R.base.one], R)
849
+ for n in range(10):
850
+ assert a == do**n
851
+ a *= do
.venv/lib/python3.12/site-packages/sympy/holonomic/tests/test_recurrence.py ADDED
@@ -0,0 +1,41 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ from sympy.holonomic.recurrence import RecurrenceOperators, RecurrenceOperator
2
+ from sympy.core.symbol import symbols
3
+ from sympy.polys.domains.rationalfield import QQ
4
+
5
+
6
+ def test_RecurrenceOperator():
7
+ n = symbols('n', integer=True)
8
+ R, Sn = RecurrenceOperators(QQ.old_poly_ring(n), 'Sn')
9
+ assert Sn*n == (n + 1)*Sn
10
+ assert Sn*n**2 == (n**2+1+2*n)*Sn
11
+ assert Sn**2*n**2 == (n**2 + 4*n + 4)*Sn**2
12
+ p = (Sn**3*n**2 + Sn*n)**2
13
+ q = (n**2 + 3*n + 2)*Sn**2 + (2*n**3 + 19*n**2 + 57*n + 52)*Sn**4 + (n**4 + 18*n**3 + \
14
+ 117*n**2 + 324*n + 324)*Sn**6
15
+ assert p == q
16
+
17
+
18
+ def test_RecurrenceOperatorEqPoly():
19
+ n = symbols('n', integer=True)
20
+ R, Sn = RecurrenceOperators(QQ.old_poly_ring(n), 'Sn')
21
+ rr = RecurrenceOperator([n**2, 0, 0], R)
22
+ rr2 = RecurrenceOperator([n**2, 1, n], R)
23
+ assert not rr == rr2
24
+
25
+ # polynomial comparison issue, see https://github.com/sympy/sympy/pull/15799
26
+ # should work once that is solved
27
+ # d = rr.listofpoly[0]
28
+ # assert rr == d
29
+
30
+ d2 = rr2.listofpoly[0]
31
+ assert not rr2 == d2
32
+
33
+
34
+ def test_RecurrenceOperatorPow():
35
+ n = symbols('n', integer=True)
36
+ R, _ = RecurrenceOperators(QQ.old_poly_ring(n), 'Sn')
37
+ rr = RecurrenceOperator([n**2, 0, 0], R)
38
+ a = RecurrenceOperator([R.base.one], R)
39
+ for m in range(10):
40
+ assert a == rr**m
41
+ a *= rr
.venv/lib/python3.12/site-packages/sympy/integrals/__init__.py ADDED
@@ -0,0 +1,45 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ """Integration functions that integrate a SymPy expression.
2
+
3
+ Examples
4
+ ========
5
+
6
+ >>> from sympy import integrate, sin
7
+ >>> from sympy.abc import x
8
+ >>> integrate(1/x,x)
9
+ log(x)
10
+ >>> integrate(sin(x),x)
11
+ -cos(x)
12
+ """
13
+ from .integrals import integrate, Integral, line_integrate
14
+ from .transforms import (mellin_transform, inverse_mellin_transform,
15
+ MellinTransform, InverseMellinTransform,
16
+ laplace_transform, inverse_laplace_transform,
17
+ laplace_correspondence, laplace_initial_conds,
18
+ LaplaceTransform, InverseLaplaceTransform,
19
+ fourier_transform, inverse_fourier_transform,
20
+ FourierTransform, InverseFourierTransform,
21
+ sine_transform, inverse_sine_transform,
22
+ SineTransform, InverseSineTransform,
23
+ cosine_transform, inverse_cosine_transform,
24
+ CosineTransform, InverseCosineTransform,
25
+ hankel_transform, inverse_hankel_transform,
26
+ HankelTransform, InverseHankelTransform)
27
+ from .singularityfunctions import singularityintegrate
28
+
29
+ __all__ = [
30
+ 'integrate', 'Integral', 'line_integrate',
31
+
32
+ 'mellin_transform', 'inverse_mellin_transform', 'MellinTransform',
33
+ 'InverseMellinTransform', 'laplace_transform',
34
+ 'inverse_laplace_transform', 'LaplaceTransform',
35
+ 'laplace_correspondence', 'laplace_initial_conds',
36
+ 'InverseLaplaceTransform', 'fourier_transform',
37
+ 'inverse_fourier_transform', 'FourierTransform',
38
+ 'InverseFourierTransform', 'sine_transform', 'inverse_sine_transform',
39
+ 'SineTransform', 'InverseSineTransform', 'cosine_transform',
40
+ 'inverse_cosine_transform', 'CosineTransform', 'InverseCosineTransform',
41
+ 'hankel_transform', 'inverse_hankel_transform', 'HankelTransform',
42
+ 'InverseHankelTransform',
43
+
44
+ 'singularityintegrate',
45
+ ]
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.venv/lib/python3.12/site-packages/sympy/integrals/benchmarks/bench_integrate.py ADDED
@@ -0,0 +1,21 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ from sympy.core.symbol import Symbol
2
+ from sympy.functions.elementary.trigonometric import sin
3
+ from sympy.integrals.integrals import integrate
4
+
5
+ x = Symbol('x')
6
+
7
+
8
+ def bench_integrate_sin():
9
+ integrate(sin(x), x)
10
+
11
+
12
+ def bench_integrate_x1sin():
13
+ integrate(x**1*sin(x), x)
14
+
15
+
16
+ def bench_integrate_x2sin():
17
+ integrate(x**2*sin(x), x)
18
+
19
+
20
+ def bench_integrate_x3sin():
21
+ integrate(x**3*sin(x), x)
.venv/lib/python3.12/site-packages/sympy/integrals/benchmarks/bench_trigintegrate.py ADDED
@@ -0,0 +1,13 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ from sympy.core.symbol import Symbol
2
+ from sympy.functions.elementary.trigonometric import sin
3
+ from sympy.integrals.trigonometry import trigintegrate
4
+
5
+ x = Symbol('x')
6
+
7
+
8
+ def timeit_trigintegrate_sin3x():
9
+ trigintegrate(sin(x)**3, x)
10
+
11
+
12
+ def timeit_trigintegrate_x2():
13
+ trigintegrate(x**2, x) # -> None
.venv/lib/python3.12/site-packages/sympy/integrals/deltafunctions.py ADDED
@@ -0,0 +1,201 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ from sympy.core.mul import Mul
2
+ from sympy.core.singleton import S
3
+ from sympy.core.sorting import default_sort_key
4
+ from sympy.functions import DiracDelta, Heaviside
5
+ from .integrals import Integral, integrate
6
+
7
+
8
+ def change_mul(node, x):
9
+ """change_mul(node, x)
10
+
11
+ Rearranges the operands of a product, bringing to front any simple
12
+ DiracDelta expression.
13
+
14
+ Explanation
15
+ ===========
16
+
17
+ If no simple DiracDelta expression was found, then all the DiracDelta
18
+ expressions are simplified (using DiracDelta.expand(diracdelta=True, wrt=x)).
19
+
20
+ Return: (dirac, new node)
21
+ Where:
22
+ o dirac is either a simple DiracDelta expression or None (if no simple
23
+ expression was found);
24
+ o new node is either a simplified DiracDelta expressions or None (if it
25
+ could not be simplified).
26
+
27
+ Examples
28
+ ========
29
+
30
+ >>> from sympy import DiracDelta, cos
31
+ >>> from sympy.integrals.deltafunctions import change_mul
32
+ >>> from sympy.abc import x, y
33
+ >>> change_mul(x*y*DiracDelta(x)*cos(x), x)
34
+ (DiracDelta(x), x*y*cos(x))
35
+ >>> change_mul(x*y*DiracDelta(x**2 - 1)*cos(x), x)
36
+ (None, x*y*cos(x)*DiracDelta(x - 1)/2 + x*y*cos(x)*DiracDelta(x + 1)/2)
37
+ >>> change_mul(x*y*DiracDelta(cos(x))*cos(x), x)
38
+ (None, None)
39
+
40
+ See Also
41
+ ========
42
+
43
+ sympy.functions.special.delta_functions.DiracDelta
44
+ deltaintegrate
45
+ """
46
+
47
+ new_args = []
48
+ dirac = None
49
+
50
+ #Sorting is needed so that we consistently collapse the same delta;
51
+ #However, we must preserve the ordering of non-commutative terms
52
+ c, nc = node.args_cnc()
53
+ sorted_args = sorted(c, key=default_sort_key)
54
+ sorted_args.extend(nc)
55
+
56
+ for arg in sorted_args:
57
+ if arg.is_Pow and isinstance(arg.base, DiracDelta):
58
+ new_args.append(arg.func(arg.base, arg.exp - 1))
59
+ arg = arg.base
60
+ if dirac is None and (isinstance(arg, DiracDelta) and arg.is_simple(x)):
61
+ dirac = arg
62
+ else:
63
+ new_args.append(arg)
64
+ if not dirac: # there was no simple dirac
65
+ new_args = []
66
+ for arg in sorted_args:
67
+ if isinstance(arg, DiracDelta):
68
+ new_args.append(arg.expand(diracdelta=True, wrt=x))
69
+ elif arg.is_Pow and isinstance(arg.base, DiracDelta):
70
+ new_args.append(arg.func(arg.base.expand(diracdelta=True, wrt=x), arg.exp))
71
+ else:
72
+ new_args.append(arg)
73
+ if new_args != sorted_args:
74
+ nnode = Mul(*new_args).expand()
75
+ else: # if the node didn't change there is nothing to do
76
+ nnode = None
77
+ return (None, nnode)
78
+ return (dirac, Mul(*new_args))
79
+
80
+
81
+ def deltaintegrate(f, x):
82
+ """
83
+ deltaintegrate(f, x)
84
+
85
+ Explanation
86
+ ===========
87
+
88
+ The idea for integration is the following:
89
+
90
+ - If we are dealing with a DiracDelta expression, i.e. DiracDelta(g(x)),
91
+ we try to simplify it.
92
+
93
+ If we could simplify it, then we integrate the resulting expression.
94
+ We already know we can integrate a simplified expression, because only
95
+ simple DiracDelta expressions are involved.
96
+
97
+ If we couldn't simplify it, there are two cases:
98
+
99
+ 1) The expression is a simple expression: we return the integral,
100
+ taking care if we are dealing with a Derivative or with a proper
101
+ DiracDelta.
102
+
103
+ 2) The expression is not simple (i.e. DiracDelta(cos(x))): we can do
104
+ nothing at all.
105
+
106
+ - If the node is a multiplication node having a DiracDelta term:
107
+
108
+ First we expand it.
109
+
110
+ If the expansion did work, then we try to integrate the expansion.
111
+
112
+ If not, we try to extract a simple DiracDelta term, then we have two
113
+ cases:
114
+
115
+ 1) We have a simple DiracDelta term, so we return the integral.
116
+
117
+ 2) We didn't have a simple term, but we do have an expression with
118
+ simplified DiracDelta terms, so we integrate this expression.
119
+
120
+ Examples
121
+ ========
122
+
123
+ >>> from sympy.abc import x, y, z
124
+ >>> from sympy.integrals.deltafunctions import deltaintegrate
125
+ >>> from sympy import sin, cos, DiracDelta
126
+ >>> deltaintegrate(x*sin(x)*cos(x)*DiracDelta(x - 1), x)
127
+ sin(1)*cos(1)*Heaviside(x - 1)
128
+ >>> deltaintegrate(y**2*DiracDelta(x - z)*DiracDelta(y - z), y)
129
+ z**2*DiracDelta(x - z)*Heaviside(y - z)
130
+
131
+ See Also
132
+ ========
133
+
134
+ sympy.functions.special.delta_functions.DiracDelta
135
+ sympy.integrals.integrals.Integral
136
+ """
137
+ if not f.has(DiracDelta):
138
+ return None
139
+
140
+ # g(x) = DiracDelta(h(x))
141
+ if f.func == DiracDelta:
142
+ h = f.expand(diracdelta=True, wrt=x)
143
+ if h == f: # can't simplify the expression
144
+ #FIXME: the second term tells whether is DeltaDirac or Derivative
145
+ #For integrating derivatives of DiracDelta we need the chain rule
146
+ if f.is_simple(x):
147
+ if (len(f.args) <= 1 or f.args[1] == 0):
148
+ return Heaviside(f.args[0])
149
+ else:
150
+ return (DiracDelta(f.args[0], f.args[1] - 1) /
151
+ f.args[0].as_poly().LC())
152
+ else: # let's try to integrate the simplified expression
153
+ fh = integrate(h, x)
154
+ return fh
155
+ elif f.is_Mul or f.is_Pow: # g(x) = a*b*c*f(DiracDelta(h(x)))*d*e
156
+ g = f.expand()
157
+ if f != g: # the expansion worked
158
+ fh = integrate(g, x)
159
+ if fh is not None and not isinstance(fh, Integral):
160
+ return fh
161
+ else:
162
+ # no expansion performed, try to extract a simple DiracDelta term
163
+ deltaterm, rest_mult = change_mul(f, x)
164
+
165
+ if not deltaterm:
166
+ if rest_mult:
167
+ fh = integrate(rest_mult, x)
168
+ return fh
169
+ else:
170
+ from sympy.solvers import solve
171
+ deltaterm = deltaterm.expand(diracdelta=True, wrt=x)
172
+ if deltaterm.is_Mul: # Take out any extracted factors
173
+ deltaterm, rest_mult_2 = change_mul(deltaterm, x)
174
+ rest_mult = rest_mult*rest_mult_2
175
+ point = solve(deltaterm.args[0], x)[0]
176
+
177
+ # Return the largest hyperreal term left after
178
+ # repeated integration by parts. For example,
179
+ #
180
+ # integrate(y*DiracDelta(x, 1),x) == y*DiracDelta(x,0), not 0
181
+ #
182
+ # This is so Integral(y*DiracDelta(x).diff(x),x).doit()
183
+ # will return y*DiracDelta(x) instead of 0 or DiracDelta(x),
184
+ # both of which are correct everywhere the value is defined
185
+ # but give wrong answers for nested integration.
186
+ n = (0 if len(deltaterm.args)==1 else deltaterm.args[1])
187
+ m = 0
188
+ while n >= 0:
189
+ r = S.NegativeOne**n*rest_mult.diff(x, n).subs(x, point)
190
+ if r.is_zero:
191
+ n -= 1
192
+ m += 1
193
+ else:
194
+ if m == 0:
195
+ return r*Heaviside(x - point)
196
+ else:
197
+ return r*DiracDelta(x,m-1)
198
+ # In some very weak sense, x=0 is still a singularity,
199
+ # but we hope will not be of any practical consequence.
200
+ return S.Zero
201
+ return None
.venv/lib/python3.12/site-packages/sympy/integrals/heurisch.py ADDED
@@ -0,0 +1,781 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ from __future__ import annotations
2
+
3
+ from collections import defaultdict
4
+ from functools import reduce
5
+ from itertools import permutations
6
+
7
+ from sympy.core.add import Add
8
+ from sympy.core.basic import Basic
9
+ from sympy.core.mul import Mul
10
+ from sympy.core.symbol import Wild, Dummy, Symbol
11
+ from sympy.core.basic import sympify
12
+ from sympy.core.numbers import Rational, pi, I
13
+ from sympy.core.relational import Eq, Ne
14
+ from sympy.core.singleton import S
15
+ from sympy.core.sorting import ordered
16
+ from sympy.core.traversal import iterfreeargs
17
+
18
+ from sympy.functions import exp, sin, cos, tan, cot, asin, atan
19
+ from sympy.functions import log, sinh, cosh, tanh, coth, asinh
20
+ from sympy.functions import sqrt, erf, erfi, li, Ei
21
+ from sympy.functions import besselj, bessely, besseli, besselk
22
+ from sympy.functions import hankel1, hankel2, jn, yn
23
+ from sympy.functions.elementary.complexes import Abs, re, im, sign, arg
24
+ from sympy.functions.elementary.exponential import LambertW
25
+ from sympy.functions.elementary.integers import floor, ceiling
26
+ from sympy.functions.elementary.piecewise import Piecewise
27
+ from sympy.functions.special.delta_functions import Heaviside, DiracDelta
28
+
29
+ from sympy.simplify.radsimp import collect
30
+
31
+ from sympy.logic.boolalg import And, Or
32
+ from sympy.utilities.iterables import uniq
33
+
34
+ from sympy.polys import quo, gcd, lcm, factor_list, cancel, PolynomialError
35
+ from sympy.polys.monomials import itermonomials
36
+ from sympy.polys.polyroots import root_factors
37
+
38
+ from sympy.polys.rings import PolyRing
39
+ from sympy.polys.solvers import solve_lin_sys
40
+ from sympy.polys.constructor import construct_domain
41
+
42
+ from sympy.integrals.integrals import integrate
43
+
44
+
45
+ def components(f, x):
46
+ """
47
+ Returns a set of all functional components of the given expression
48
+ which includes symbols, function applications and compositions and
49
+ non-integer powers. Fractional powers are collected with
50
+ minimal, positive exponents.
51
+
52
+ Examples
53
+ ========
54
+
55
+ >>> from sympy import cos, sin
56
+ >>> from sympy.abc import x
57
+ >>> from sympy.integrals.heurisch import components
58
+
59
+ >>> components(sin(x)*cos(x)**2, x)
60
+ {x, sin(x), cos(x)}
61
+
62
+ See Also
63
+ ========
64
+
65
+ heurisch
66
+ """
67
+ result = set()
68
+
69
+ if f.has_free(x):
70
+ if f.is_symbol and f.is_commutative:
71
+ result.add(f)
72
+ elif f.is_Function or f.is_Derivative:
73
+ for g in f.args:
74
+ result |= components(g, x)
75
+
76
+ result.add(f)
77
+ elif f.is_Pow:
78
+ result |= components(f.base, x)
79
+
80
+ if not f.exp.is_Integer:
81
+ if f.exp.is_Rational:
82
+ result.add(f.base**Rational(1, f.exp.q))
83
+ else:
84
+ result |= components(f.exp, x) | {f}
85
+ else:
86
+ for g in f.args:
87
+ result |= components(g, x)
88
+
89
+ return result
90
+
91
+ # name -> [] of symbols
92
+ _symbols_cache: dict[str, list[Dummy]] = {}
93
+
94
+
95
+ # NB @cacheit is not convenient here
96
+ def _symbols(name, n):
97
+ """get vector of symbols local to this module"""
98
+ try:
99
+ lsyms = _symbols_cache[name]
100
+ except KeyError:
101
+ lsyms = []
102
+ _symbols_cache[name] = lsyms
103
+
104
+ while len(lsyms) < n:
105
+ lsyms.append( Dummy('%s%i' % (name, len(lsyms))) )
106
+
107
+ return lsyms[:n]
108
+
109
+
110
+ def heurisch_wrapper(f, x, rewrite=False, hints=None, mappings=None, retries=3,
111
+ degree_offset=0, unnecessary_permutations=None,
112
+ _try_heurisch=None):
113
+ """
114
+ A wrapper around the heurisch integration algorithm.
115
+
116
+ Explanation
117
+ ===========
118
+
119
+ This method takes the result from heurisch and checks for poles in the
120
+ denominator. For each of these poles, the integral is reevaluated, and
121
+ the final integration result is given in terms of a Piecewise.
122
+
123
+ Examples
124
+ ========
125
+
126
+ >>> from sympy import cos, symbols
127
+ >>> from sympy.integrals.heurisch import heurisch, heurisch_wrapper
128
+ >>> n, x = symbols('n x')
129
+ >>> heurisch(cos(n*x), x)
130
+ sin(n*x)/n
131
+ >>> heurisch_wrapper(cos(n*x), x)
132
+ Piecewise((sin(n*x)/n, Ne(n, 0)), (x, True))
133
+
134
+ See Also
135
+ ========
136
+
137
+ heurisch
138
+ """
139
+ from sympy.solvers.solvers import solve, denoms
140
+ f = sympify(f)
141
+ if not f.has_free(x):
142
+ return f*x
143
+
144
+ res = heurisch(f, x, rewrite, hints, mappings, retries, degree_offset,
145
+ unnecessary_permutations, _try_heurisch)
146
+ if not isinstance(res, Basic):
147
+ return res
148
+
149
+ # We consider each denominator in the expression, and try to find
150
+ # cases where one or more symbolic denominator might be zero. The
151
+ # conditions for these cases are stored in the list slns.
152
+ #
153
+ # Since denoms returns a set we use ordered. This is important because the
154
+ # ordering of slns determines the order of the resulting Piecewise so we
155
+ # need a deterministic order here to make the output deterministic.
156
+ slns = []
157
+ for d in ordered(denoms(res)):
158
+ try:
159
+ slns += solve([d], dict=True, exclude=(x,))
160
+ except NotImplementedError:
161
+ pass
162
+ if not slns:
163
+ return res
164
+ slns = list(uniq(slns))
165
+ # Remove the solutions corresponding to poles in the original expression.
166
+ slns0 = []
167
+ for d in denoms(f):
168
+ try:
169
+ slns0 += solve([d], dict=True, exclude=(x,))
170
+ except NotImplementedError:
171
+ pass
172
+ slns = [s for s in slns if s not in slns0]
173
+ if not slns:
174
+ return res
175
+ if len(slns) > 1:
176
+ eqs = []
177
+ for sub_dict in slns:
178
+ eqs.extend([Eq(key, value) for key, value in sub_dict.items()])
179
+ slns = solve(eqs, dict=True, exclude=(x,)) + slns
180
+ # For each case listed in the list slns, we reevaluate the integral.
181
+ pairs = []
182
+ for sub_dict in slns:
183
+ expr = heurisch(f.subs(sub_dict), x, rewrite, hints, mappings, retries,
184
+ degree_offset, unnecessary_permutations,
185
+ _try_heurisch)
186
+ cond = And(*[Eq(key, value) for key, value in sub_dict.items()])
187
+ generic = Or(*[Ne(key, value) for key, value in sub_dict.items()])
188
+ if expr is None:
189
+ expr = integrate(f.subs(sub_dict),x)
190
+ pairs.append((expr, cond))
191
+ # If there is one condition, put the generic case first. Otherwise,
192
+ # doing so may lead to longer Piecewise formulas
193
+ if len(pairs) == 1:
194
+ pairs = [(heurisch(f, x, rewrite, hints, mappings, retries,
195
+ degree_offset, unnecessary_permutations,
196
+ _try_heurisch),
197
+ generic),
198
+ (pairs[0][0], True)]
199
+ else:
200
+ pairs.append((heurisch(f, x, rewrite, hints, mappings, retries,
201
+ degree_offset, unnecessary_permutations,
202
+ _try_heurisch),
203
+ True))
204
+ return Piecewise(*pairs)
205
+
206
+ class BesselTable:
207
+ """
208
+ Derivatives of Bessel functions of orders n and n-1
209
+ in terms of each other.
210
+
211
+ See the docstring of DiffCache.
212
+ """
213
+
214
+ def __init__(self):
215
+ self.table = {}
216
+ self.n = Dummy('n')
217
+ self.z = Dummy('z')
218
+ self._create_table()
219
+
220
+ def _create_table(t):
221
+ table, n, z = t.table, t.n, t.z
222
+ for f in (besselj, bessely, hankel1, hankel2):
223
+ table[f] = (f(n-1, z) - n*f(n, z)/z,
224
+ (n-1)*f(n-1, z)/z - f(n, z))
225
+
226
+ f = besseli
227
+ table[f] = (f(n-1, z) - n*f(n, z)/z,
228
+ (n-1)*f(n-1, z)/z + f(n, z))
229
+ f = besselk
230
+ table[f] = (-f(n-1, z) - n*f(n, z)/z,
231
+ (n-1)*f(n-1, z)/z - f(n, z))
232
+
233
+ for f in (jn, yn):
234
+ table[f] = (f(n-1, z) - (n+1)*f(n, z)/z,
235
+ (n-1)*f(n-1, z)/z - f(n, z))
236
+
237
+ def diffs(t, f, n, z):
238
+ if f in t.table:
239
+ diff0, diff1 = t.table[f]
240
+ repl = [(t.n, n), (t.z, z)]
241
+ return (diff0.subs(repl), diff1.subs(repl))
242
+
243
+ def has(t, f):
244
+ return f in t.table
245
+
246
+ _bessel_table = None
247
+
248
+ class DiffCache:
249
+ """
250
+ Store for derivatives of expressions.
251
+
252
+ Explanation
253
+ ===========
254
+
255
+ The standard form of the derivative of a Bessel function of order n
256
+ contains two Bessel functions of orders n-1 and n+1, respectively.
257
+ Such forms cannot be used in parallel Risch algorithm, because
258
+ there is a linear recurrence relation between the three functions
259
+ while the algorithm expects that functions and derivatives are
260
+ represented in terms of algebraically independent transcendentals.
261
+
262
+ The solution is to take two of the functions, e.g., those of orders
263
+ n and n-1, and to express the derivatives in terms of the pair.
264
+ To guarantee that the proper form is used the two derivatives are
265
+ cached as soon as one is encountered.
266
+
267
+ Derivatives of other functions are also cached at no extra cost.
268
+ All derivatives are with respect to the same variable `x`.
269
+ """
270
+
271
+ def __init__(self, x):
272
+ self.cache = {}
273
+ self.x = x
274
+
275
+ global _bessel_table
276
+ if not _bessel_table:
277
+ _bessel_table = BesselTable()
278
+
279
+ def get_diff(self, f):
280
+ cache = self.cache
281
+
282
+ if f in cache:
283
+ pass
284
+ elif (not hasattr(f, 'func') or
285
+ not _bessel_table.has(f.func)):
286
+ cache[f] = cancel(f.diff(self.x))
287
+ else:
288
+ n, z = f.args
289
+ d0, d1 = _bessel_table.diffs(f.func, n, z)
290
+ dz = self.get_diff(z)
291
+ cache[f] = d0*dz
292
+ cache[f.func(n-1, z)] = d1*dz
293
+
294
+ return cache[f]
295
+
296
+ def heurisch(f, x, rewrite=False, hints=None, mappings=None, retries=3,
297
+ degree_offset=0, unnecessary_permutations=None,
298
+ _try_heurisch=None):
299
+ """
300
+ Compute indefinite integral using heuristic Risch algorithm.
301
+
302
+ Explanation
303
+ ===========
304
+
305
+ This is a heuristic approach to indefinite integration in finite
306
+ terms using the extended heuristic (parallel) Risch algorithm, based
307
+ on Manuel Bronstein's "Poor Man's Integrator".
308
+
309
+ The algorithm supports various classes of functions including
310
+ transcendental elementary or special functions like Airy,
311
+ Bessel, Whittaker and Lambert.
312
+
313
+ Note that this algorithm is not a decision procedure. If it isn't
314
+ able to compute the antiderivative for a given function, then this is
315
+ not a proof that such a functions does not exist. One should use
316
+ recursive Risch algorithm in such case. It's an open question if
317
+ this algorithm can be made a full decision procedure.
318
+
319
+ This is an internal integrator procedure. You should use top level
320
+ 'integrate' function in most cases, as this procedure needs some
321
+ preprocessing steps and otherwise may fail.
322
+
323
+ Specification
324
+ =============
325
+
326
+ heurisch(f, x, rewrite=False, hints=None)
327
+
328
+ where
329
+ f : expression
330
+ x : symbol
331
+
332
+ rewrite -> force rewrite 'f' in terms of 'tan' and 'tanh'
333
+ hints -> a list of functions that may appear in anti-derivate
334
+
335
+ - hints = None --> no suggestions at all
336
+ - hints = [ ] --> try to figure out
337
+ - hints = [f1, ..., fn] --> we know better
338
+
339
+ Examples
340
+ ========
341
+
342
+ >>> from sympy import tan
343
+ >>> from sympy.integrals.heurisch import heurisch
344
+ >>> from sympy.abc import x, y
345
+
346
+ >>> heurisch(y*tan(x), x)
347
+ y*log(tan(x)**2 + 1)/2
348
+
349
+ See Manuel Bronstein's "Poor Man's Integrator":
350
+
351
+ References
352
+ ==========
353
+
354
+ .. [1] https://www-sop.inria.fr/cafe/Manuel.Bronstein/pmint/index.html
355
+
356
+ For more information on the implemented algorithm refer to:
357
+
358
+ .. [2] K. Geddes, L. Stefanus, On the Risch-Norman Integration
359
+ Method and its Implementation in Maple, Proceedings of
360
+ ISSAC'89, ACM Press, 212-217.
361
+
362
+ .. [3] J. H. Davenport, On the Parallel Risch Algorithm (I),
363
+ Proceedings of EUROCAM'82, LNCS 144, Springer, 144-157.
364
+
365
+ .. [4] J. H. Davenport, On the Parallel Risch Algorithm (III):
366
+ Use of Tangents, SIGSAM Bulletin 16 (1982), 3-6.
367
+
368
+ .. [5] J. H. Davenport, B. M. Trager, On the Parallel Risch
369
+ Algorithm (II), ACM Transactions on Mathematical
370
+ Software 11 (1985), 356-362.
371
+
372
+ See Also
373
+ ========
374
+
375
+ sympy.integrals.integrals.Integral.doit
376
+ sympy.integrals.integrals.Integral
377
+ sympy.integrals.heurisch.components
378
+ """
379
+ f = sympify(f)
380
+
381
+ # There are some functions that Heurisch cannot currently handle,
382
+ # so do not even try.
383
+ # Set _try_heurisch=True to skip this check
384
+ if _try_heurisch is not True:
385
+ if f.has(Abs, re, im, sign, Heaviside, DiracDelta, floor, ceiling, arg):
386
+ return
387
+
388
+ if not f.has_free(x):
389
+ return f*x
390
+
391
+ if not f.is_Add:
392
+ indep, f = f.as_independent(x)
393
+ else:
394
+ indep = S.One
395
+
396
+ rewritables = {
397
+ (sin, cos, cot): tan,
398
+ (sinh, cosh, coth): tanh,
399
+ }
400
+
401
+ if rewrite:
402
+ for candidates, rule in rewritables.items():
403
+ f = f.rewrite(candidates, rule)
404
+ else:
405
+ for candidates in rewritables.keys():
406
+ if f.has(*candidates):
407
+ break
408
+ else:
409
+ rewrite = True
410
+
411
+ terms = components(f, x)
412
+ dcache = DiffCache(x)
413
+
414
+ if hints is not None:
415
+ if not hints:
416
+ a = Wild('a', exclude=[x])
417
+ b = Wild('b', exclude=[x])
418
+ c = Wild('c', exclude=[x])
419
+
420
+ for g in set(terms): # using copy of terms
421
+ if g.is_Function:
422
+ if isinstance(g, li):
423
+ M = g.args[0].match(a*x**b)
424
+
425
+ if M is not None:
426
+ terms.add( x*(li(M[a]*x**M[b]) - (M[a]*x**M[b])**(-1/M[b])*Ei((M[b]+1)*log(M[a]*x**M[b])/M[b])) )
427
+ #terms.add( x*(li(M[a]*x**M[b]) - (x**M[b])**(-1/M[b])*Ei((M[b]+1)*log(M[a]*x**M[b])/M[b])) )
428
+ #terms.add( x*(li(M[a]*x**M[b]) - x*Ei((M[b]+1)*log(M[a]*x**M[b])/M[b])) )
429
+ #terms.add( li(M[a]*x**M[b]) - Ei((M[b]+1)*log(M[a]*x**M[b])/M[b]) )
430
+
431
+ elif isinstance(g, exp):
432
+ M = g.args[0].match(a*x**2)
433
+
434
+ if M is not None:
435
+ if M[a].is_positive:
436
+ terms.add(erfi(sqrt(M[a])*x))
437
+ else: # M[a].is_negative or unknown
438
+ terms.add(erf(sqrt(-M[a])*x))
439
+
440
+ M = g.args[0].match(a*x**2 + b*x + c)
441
+
442
+ if M is not None:
443
+ if M[a].is_positive:
444
+ terms.add(sqrt(pi/4*(-M[a]))*exp(M[c] - M[b]**2/(4*M[a]))*
445
+ erfi(sqrt(M[a])*x + M[b]/(2*sqrt(M[a]))))
446
+ elif M[a].is_negative:
447
+ terms.add(sqrt(pi/4*(-M[a]))*exp(M[c] - M[b]**2/(4*M[a]))*
448
+ erf(sqrt(-M[a])*x - M[b]/(2*sqrt(-M[a]))))
449
+
450
+ M = g.args[0].match(a*log(x)**2)
451
+
452
+ if M is not None:
453
+ if M[a].is_positive:
454
+ terms.add(erfi(sqrt(M[a])*log(x) + 1/(2*sqrt(M[a]))))
455
+ if M[a].is_negative:
456
+ terms.add(erf(sqrt(-M[a])*log(x) - 1/(2*sqrt(-M[a]))))
457
+
458
+ elif g.is_Pow:
459
+ if g.exp.is_Rational and g.exp.q == 2:
460
+ M = g.base.match(a*x**2 + b)
461
+
462
+ if M is not None and M[b].is_positive:
463
+ if M[a].is_positive:
464
+ terms.add(asinh(sqrt(M[a]/M[b])*x))
465
+ elif M[a].is_negative:
466
+ terms.add(asin(sqrt(-M[a]/M[b])*x))
467
+
468
+ M = g.base.match(a*x**2 - b)
469
+
470
+ if M is not None and M[b].is_positive:
471
+ if M[a].is_positive:
472
+ dF = 1/sqrt(M[a]*x**2 - M[b])
473
+ F = log(2*sqrt(M[a])*sqrt(M[a]*x**2 - M[b]) + 2*M[a]*x)/sqrt(M[a])
474
+ dcache.cache[F] = dF # hack: F.diff(x) doesn't automatically simplify to f
475
+ terms.add(F)
476
+ elif M[a].is_negative:
477
+ terms.add(-M[b]/2*sqrt(-M[a])*
478
+ atan(sqrt(-M[a])*x/sqrt(M[a]*x**2 - M[b])))
479
+
480
+ else:
481
+ terms |= set(hints)
482
+
483
+ for g in set(terms): # using copy of terms
484
+ terms |= components(dcache.get_diff(g), x)
485
+
486
+ # XXX: The commented line below makes heurisch more deterministic wrt
487
+ # PYTHONHASHSEED and the iteration order of sets. There are other places
488
+ # where sets are iterated over but this one is possibly the most important.
489
+ # Theoretically the order here should not matter but different orderings
490
+ # can expose potential bugs in the different code paths so potentially it
491
+ # is better to keep the non-determinism.
492
+ #
493
+ # terms = list(ordered(terms))
494
+
495
+ # TODO: caching is significant factor for why permutations work at all. Change this.
496
+ V = _symbols('x', len(terms))
497
+
498
+
499
+ # sort mapping expressions from largest to smallest (last is always x).
500
+ mapping = list(reversed(list(zip(*ordered( #
501
+ [(a[0].as_independent(x)[1], a) for a in zip(terms, V)])))[1])) #
502
+ rev_mapping = {v: k for k, v in mapping} #
503
+ if mappings is None: #
504
+ # optimizing the number of permutations of mapping #
505
+ assert mapping[-1][0] == x # if not, find it and correct this comment
506
+ unnecessary_permutations = [mapping.pop(-1)]
507
+ # permute types of objects
508
+ types = defaultdict(list)
509
+ for i in mapping:
510
+ e, _ = i
511
+ types[type(e)].append(i)
512
+ mapping = [types[i] for i in types]
513
+ def _iter_mappings():
514
+ for i in permutations(mapping):
515
+ # make the expression of a given type be ordered
516
+ yield [j for i in i for j in ordered(i)]
517
+ mappings = _iter_mappings()
518
+ else:
519
+ unnecessary_permutations = unnecessary_permutations or []
520
+
521
+ def _substitute(expr):
522
+ return expr.subs(mapping)
523
+
524
+ for mapping in mappings:
525
+ mapping = list(mapping)
526
+ mapping = mapping + unnecessary_permutations
527
+ diffs = [ _substitute(dcache.get_diff(g)) for g in terms ]
528
+ denoms = [ g.as_numer_denom()[1] for g in diffs ]
529
+ if all(h.is_polynomial(*V) for h in denoms) and _substitute(f).is_rational_function(*V):
530
+ denom = reduce(lambda p, q: lcm(p, q, *V), denoms)
531
+ break
532
+ else:
533
+ if not rewrite:
534
+ result = heurisch(f, x, rewrite=True, hints=hints,
535
+ unnecessary_permutations=unnecessary_permutations)
536
+
537
+ if result is not None:
538
+ return indep*result
539
+ return None
540
+
541
+ numers = [ cancel(denom*g) for g in diffs ]
542
+ def _derivation(h):
543
+ return Add(*[ d * h.diff(v) for d, v in zip(numers, V) ])
544
+
545
+ def _deflation(p):
546
+ for y in V:
547
+ if not p.has(y):
548
+ continue
549
+
550
+ if _derivation(p) is not S.Zero:
551
+ c, q = p.as_poly(y).primitive()
552
+ return _deflation(c)*gcd(q, q.diff(y)).as_expr()
553
+
554
+ return p
555
+
556
+ def _splitter(p):
557
+ for y in V:
558
+ if not p.has(y):
559
+ continue
560
+
561
+ if _derivation(y) is not S.Zero:
562
+ c, q = p.as_poly(y).primitive()
563
+
564
+ q = q.as_expr()
565
+
566
+ h = gcd(q, _derivation(q), y)
567
+ s = quo(h, gcd(q, q.diff(y), y), y)
568
+
569
+ c_split = _splitter(c)
570
+
571
+ if s.as_poly(y).degree() == 0:
572
+ return (c_split[0], q * c_split[1])
573
+
574
+ q_split = _splitter(cancel(q / s))
575
+
576
+ return (c_split[0]*q_split[0]*s, c_split[1]*q_split[1])
577
+
578
+ return (S.One, p)
579
+
580
+ special = {}
581
+
582
+ for term in terms:
583
+ if term.is_Function:
584
+ if isinstance(term, tan):
585
+ special[1 + _substitute(term)**2] = False
586
+ elif isinstance(term, tanh):
587
+ special[1 + _substitute(term)] = False
588
+ special[1 - _substitute(term)] = False
589
+ elif isinstance(term, LambertW):
590
+ special[_substitute(term)] = True
591
+
592
+ F = _substitute(f)
593
+
594
+ P, Q = F.as_numer_denom()
595
+
596
+ u_split = _splitter(denom)
597
+ v_split = _splitter(Q)
598
+
599
+ polys = set(list(v_split) + [ u_split[0] ] + list(special.keys()))
600
+
601
+ s = u_split[0] * Mul(*[ k for k, v in special.items() if v ])
602
+ polified = [ p.as_poly(*V) for p in [s, P, Q] ]
603
+
604
+ if None in polified:
605
+ return None
606
+
607
+ #--- definitions for _integrate
608
+ a, b, c = [ p.total_degree() for p in polified ]
609
+
610
+ poly_denom = (s * v_split[0] * _deflation(v_split[1])).as_expr()
611
+
612
+ def _exponent(g):
613
+ if g.is_Pow:
614
+ if g.exp.is_Rational and g.exp.q != 1:
615
+ if g.exp.p > 0:
616
+ return g.exp.p + g.exp.q - 1
617
+ else:
618
+ return abs(g.exp.p + g.exp.q)
619
+ else:
620
+ return 1
621
+ elif not g.is_Atom and g.args:
622
+ return max(_exponent(h) for h in g.args)
623
+ else:
624
+ return 1
625
+
626
+ A, B = _exponent(f), a + max(b, c)
627
+
628
+ if A > 1 and B > 1:
629
+ monoms = tuple(ordered(itermonomials(V, A + B - 1 + degree_offset)))
630
+ else:
631
+ monoms = tuple(ordered(itermonomials(V, A + B + degree_offset)))
632
+
633
+ poly_coeffs = _symbols('A', len(monoms))
634
+
635
+ poly_part = Add(*[ poly_coeffs[i]*monomial
636
+ for i, monomial in enumerate(monoms) ])
637
+
638
+ reducibles = set()
639
+
640
+ for poly in ordered(polys):
641
+ coeff, factors = factor_list(poly, *V)
642
+ reducibles.add(coeff)
643
+ reducibles.update(fact for fact, mul in factors)
644
+
645
+ def _integrate(field=None):
646
+ atans = set()
647
+ pairs = set()
648
+
649
+ if field == 'Q':
650
+ irreducibles = set(reducibles)
651
+ else:
652
+ setV = set(V)
653
+ irreducibles = set()
654
+ for poly in ordered(reducibles):
655
+ zV = setV & set(iterfreeargs(poly))
656
+ for z in ordered(zV):
657
+ s = set(root_factors(poly, z, filter=field))
658
+ irreducibles |= s
659
+ break
660
+
661
+ log_part, atan_part = [], []
662
+
663
+ for poly in ordered(irreducibles):
664
+ m = collect(poly, I, evaluate=False)
665
+ y = m.get(I, S.Zero)
666
+ if y:
667
+ x = m.get(S.One, S.Zero)
668
+ if x.has(I) or y.has(I):
669
+ continue # nontrivial x + I*y
670
+ pairs.add((x, y))
671
+ irreducibles.remove(poly)
672
+
673
+ while pairs:
674
+ x, y = pairs.pop()
675
+ if (x, -y) in pairs:
676
+ pairs.remove((x, -y))
677
+ # Choosing b with no minus sign
678
+ if y.could_extract_minus_sign():
679
+ y = -y
680
+ irreducibles.add(x*x + y*y)
681
+ atans.add(atan(x/y))
682
+ else:
683
+ irreducibles.add(x + I*y)
684
+
685
+
686
+ B = _symbols('B', len(irreducibles))
687
+ C = _symbols('C', len(atans))
688
+
689
+ # Note: the ordering matters here
690
+ for poly, b in reversed(list(zip(ordered(irreducibles), B))):
691
+ if poly.has(*V):
692
+ poly_coeffs.append(b)
693
+ log_part.append(b * log(poly))
694
+
695
+ for poly, c in reversed(list(zip(ordered(atans), C))):
696
+ if poly.has(*V):
697
+ poly_coeffs.append(c)
698
+ atan_part.append(c * poly)
699
+
700
+ # TODO: Currently it's better to use symbolic expressions here instead
701
+ # of rational functions, because it's simpler and FracElement doesn't
702
+ # give big speed improvement yet. This is because cancellation is slow
703
+ # due to slow polynomial GCD algorithms. If this gets improved then
704
+ # revise this code.
705
+ candidate = poly_part/poly_denom + Add(*log_part) + Add(*atan_part)
706
+ h = F - _derivation(candidate) / denom
707
+ raw_numer = h.as_numer_denom()[0]
708
+
709
+ # Rewrite raw_numer as a polynomial in K[coeffs][V] where K is a field
710
+ # that we have to determine. We can't use simply atoms() because log(3),
711
+ # sqrt(y) and similar expressions can appear, leading to non-trivial
712
+ # domains.
713
+ syms = set(poly_coeffs) | set(V)
714
+ non_syms = set()
715
+
716
+ def find_non_syms(expr):
717
+ if expr.is_Integer or expr.is_Rational:
718
+ pass # ignore trivial numbers
719
+ elif expr in syms:
720
+ pass # ignore variables
721
+ elif not expr.has_free(*syms):
722
+ non_syms.add(expr)
723
+ elif expr.is_Add or expr.is_Mul or expr.is_Pow:
724
+ list(map(find_non_syms, expr.args))
725
+ else:
726
+ # TODO: Non-polynomial expression. This should have been
727
+ # filtered out at an earlier stage.
728
+ raise PolynomialError
729
+
730
+ try:
731
+ find_non_syms(raw_numer)
732
+ except PolynomialError:
733
+ return None
734
+ else:
735
+ ground, _ = construct_domain(non_syms, field=True)
736
+
737
+ coeff_ring = PolyRing(poly_coeffs, ground)
738
+ ring = PolyRing(V, coeff_ring)
739
+ try:
740
+ numer = ring.from_expr(raw_numer)
741
+ except ValueError:
742
+ raise PolynomialError
743
+ solution = solve_lin_sys(numer.coeffs(), coeff_ring, _raw=False)
744
+
745
+ if solution is None:
746
+ return None
747
+ else:
748
+ return candidate.xreplace(solution).xreplace(
749
+ dict(zip(poly_coeffs, [S.Zero]*len(poly_coeffs))))
750
+
751
+ if all(isinstance(_, Symbol) for _ in V):
752
+ more_free = F.free_symbols - set(V)
753
+ else:
754
+ Fd = F.as_dummy()
755
+ more_free = Fd.xreplace(dict(zip(V, (Dummy() for _ in V)))
756
+ ).free_symbols & Fd.free_symbols
757
+ if not more_free:
758
+ # all free generators are identified in V
759
+ solution = _integrate('Q')
760
+
761
+ if solution is None:
762
+ solution = _integrate()
763
+ else:
764
+ solution = _integrate()
765
+
766
+ if solution is not None:
767
+ antideriv = solution.subs(rev_mapping)
768
+ antideriv = cancel(antideriv).expand()
769
+
770
+ if antideriv.is_Add:
771
+ antideriv = antideriv.as_independent(x)[1]
772
+
773
+ return indep*antideriv
774
+ else:
775
+ if retries >= 0:
776
+ result = heurisch(f, x, mappings=mappings, rewrite=rewrite, hints=hints, retries=retries - 1, unnecessary_permutations=unnecessary_permutations)
777
+
778
+ if result is not None:
779
+ return indep*result
780
+
781
+ return None
.venv/lib/python3.12/site-packages/sympy/integrals/integrals.py ADDED
@@ -0,0 +1,1640 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ from __future__ import annotations
2
+
3
+ from sympy.concrete.expr_with_limits import AddWithLimits
4
+ from sympy.core.add import Add
5
+ from sympy.core.basic import Basic
6
+ from sympy.core.containers import Tuple
7
+ from sympy.core.expr import Expr
8
+ from sympy.core.exprtools import factor_terms
9
+ from sympy.core.function import diff
10
+ from sympy.core.logic import fuzzy_bool
11
+ from sympy.core.mul import Mul
12
+ from sympy.core.numbers import oo, pi
13
+ from sympy.core.relational import Ne
14
+ from sympy.core.singleton import S
15
+ from sympy.core.symbol import (Dummy, Symbol, Wild)
16
+ from sympy.core.sympify import sympify
17
+ from sympy.functions import Piecewise, sqrt, piecewise_fold, tan, cot, atan
18
+ from sympy.functions.elementary.exponential import log
19
+ from sympy.functions.elementary.integers import floor
20
+ from sympy.functions.elementary.complexes import Abs, sign
21
+ from sympy.functions.elementary.miscellaneous import Min, Max
22
+ from sympy.functions.special.singularity_functions import Heaviside
23
+ from .rationaltools import ratint
24
+ from sympy.matrices import MatrixBase
25
+ from sympy.polys import Poly, PolynomialError
26
+ from sympy.series.formal import FormalPowerSeries
27
+ from sympy.series.limits import limit
28
+ from sympy.series.order import Order
29
+ from sympy.tensor.functions import shape
30
+ from sympy.utilities.exceptions import sympy_deprecation_warning
31
+ from sympy.utilities.iterables import is_sequence
32
+ from sympy.utilities.misc import filldedent
33
+
34
+
35
+ class Integral(AddWithLimits):
36
+ """Represents unevaluated integral."""
37
+
38
+ __slots__ = ()
39
+
40
+ args: tuple[Expr, Tuple] # type: ignore
41
+
42
+ def __new__(cls, function, *symbols, **assumptions) -> Integral:
43
+ """Create an unevaluated integral.
44
+
45
+ Explanation
46
+ ===========
47
+
48
+ Arguments are an integrand followed by one or more limits.
49
+
50
+ If no limits are given and there is only one free symbol in the
51
+ expression, that symbol will be used, otherwise an error will be
52
+ raised.
53
+
54
+ >>> from sympy import Integral
55
+ >>> from sympy.abc import x, y
56
+ >>> Integral(x)
57
+ Integral(x, x)
58
+ >>> Integral(y)
59
+ Integral(y, y)
60
+
61
+ When limits are provided, they are interpreted as follows (using
62
+ ``x`` as though it were the variable of integration):
63
+
64
+ (x,) or x - indefinite integral
65
+ (x, a) - "evaluate at" integral is an abstract antiderivative
66
+ (x, a, b) - definite integral
67
+
68
+ The ``as_dummy`` method can be used to see which symbols cannot be
69
+ targeted by subs: those with a prepended underscore cannot be
70
+ changed with ``subs``. (Also, the integration variables themselves --
71
+ the first element of a limit -- can never be changed by subs.)
72
+
73
+ >>> i = Integral(x, x)
74
+ >>> at = Integral(x, (x, x))
75
+ >>> i.as_dummy()
76
+ Integral(x, x)
77
+ >>> at.as_dummy()
78
+ Integral(_0, (_0, x))
79
+
80
+ """
81
+
82
+ #This will help other classes define their own definitions
83
+ #of behaviour with Integral.
84
+ if hasattr(function, '_eval_Integral'):
85
+ return function._eval_Integral(*symbols, **assumptions)
86
+
87
+ if isinstance(function, Poly):
88
+ sympy_deprecation_warning(
89
+ """
90
+ integrate(Poly) and Integral(Poly) are deprecated. Instead,
91
+ use the Poly.integrate() method, or convert the Poly to an
92
+ Expr first with the Poly.as_expr() method.
93
+ """,
94
+ deprecated_since_version="1.6",
95
+ active_deprecations_target="deprecated-integrate-poly")
96
+
97
+ obj = AddWithLimits.__new__(cls, function, *symbols, **assumptions)
98
+ return obj
99
+
100
+ def __getnewargs__(self):
101
+ return (self.function,) + tuple([tuple(xab) for xab in self.limits])
102
+
103
+ @property
104
+ def free_symbols(self):
105
+ """
106
+ This method returns the symbols that will exist when the
107
+ integral is evaluated. This is useful if one is trying to
108
+ determine whether an integral depends on a certain
109
+ symbol or not.
110
+
111
+ Examples
112
+ ========
113
+
114
+ >>> from sympy import Integral
115
+ >>> from sympy.abc import x, y
116
+ >>> Integral(x, (x, y, 1)).free_symbols
117
+ {y}
118
+
119
+ See Also
120
+ ========
121
+
122
+ sympy.concrete.expr_with_limits.ExprWithLimits.function
123
+ sympy.concrete.expr_with_limits.ExprWithLimits.limits
124
+ sympy.concrete.expr_with_limits.ExprWithLimits.variables
125
+ """
126
+ return super().free_symbols
127
+
128
+ def _eval_is_zero(self):
129
+ # This is a very naive and quick test, not intended to do the integral to
130
+ # answer whether it is zero or not, e.g. Integral(sin(x), (x, 0, 2*pi))
131
+ # is zero but this routine should return None for that case. But, like
132
+ # Mul, there are trivial situations for which the integral will be
133
+ # zero so we check for those.
134
+ if self.function.is_zero:
135
+ return True
136
+ got_none = False
137
+ for l in self.limits:
138
+ if len(l) == 3:
139
+ z = (l[1] == l[2]) or (l[1] - l[2]).is_zero
140
+ if z:
141
+ return True
142
+ elif z is None:
143
+ got_none = True
144
+ free = self.function.free_symbols
145
+ for xab in self.limits:
146
+ if len(xab) == 1:
147
+ free.add(xab[0])
148
+ continue
149
+ if len(xab) == 2 and xab[0] not in free:
150
+ if xab[1].is_zero:
151
+ return True
152
+ elif xab[1].is_zero is None:
153
+ got_none = True
154
+ # take integration symbol out of free since it will be replaced
155
+ # with the free symbols in the limits
156
+ free.discard(xab[0])
157
+ # add in the new symbols
158
+ for i in xab[1:]:
159
+ free.update(i.free_symbols)
160
+ if self.function.is_zero is False and got_none is False:
161
+ return False
162
+
163
+ def transform(self, x, u):
164
+ r"""
165
+ Performs a change of variables from `x` to `u` using the relationship
166
+ given by `x` and `u` which will define the transformations `f` and `F`
167
+ (which are inverses of each other) as follows:
168
+
169
+ 1) If `x` is a Symbol (which is a variable of integration) then `u`
170
+ will be interpreted as some function, f(u), with inverse F(u).
171
+ This, in effect, just makes the substitution of x with f(x).
172
+
173
+ 2) If `u` is a Symbol then `x` will be interpreted as some function,
174
+ F(x), with inverse f(u). This is commonly referred to as
175
+ u-substitution.
176
+
177
+ Once f and F have been identified, the transformation is made as
178
+ follows:
179
+
180
+ .. math:: \int_a^b x \mathrm{d}x \rightarrow \int_{F(a)}^{F(b)} f(x)
181
+ \frac{\mathrm{d}}{\mathrm{d}x}
182
+
183
+ where `F(x)` is the inverse of `f(x)` and the limits and integrand have
184
+ been corrected so as to retain the same value after integration.
185
+
186
+ Notes
187
+ =====
188
+
189
+ The mappings, F(x) or f(u), must lead to a unique integral. Linear
190
+ or rational linear expression, ``2*x``, ``1/x`` and ``sqrt(x)``, will
191
+ always work; quadratic expressions like ``x**2 - 1`` are acceptable
192
+ as long as the resulting integrand does not depend on the sign of
193
+ the solutions (see examples).
194
+
195
+ The integral will be returned unchanged if ``x`` is not a variable of
196
+ integration.
197
+
198
+ ``x`` must be (or contain) only one of of the integration variables. If
199
+ ``u`` has more than one free symbol then it should be sent as a tuple
200
+ (``u``, ``uvar``) where ``uvar`` identifies which variable is replacing
201
+ the integration variable.
202
+ XXX can it contain another integration variable?
203
+
204
+ Examples
205
+ ========
206
+
207
+ >>> from sympy.abc import a, x, u
208
+ >>> from sympy import Integral, cos, sqrt
209
+
210
+ >>> i = Integral(x*cos(x**2 - 1), (x, 0, 1))
211
+
212
+ transform can change the variable of integration
213
+
214
+ >>> i.transform(x, u)
215
+ Integral(u*cos(u**2 - 1), (u, 0, 1))
216
+
217
+ transform can perform u-substitution as long as a unique
218
+ integrand is obtained:
219
+
220
+ >>> ui = i.transform(x**2 - 1, u)
221
+ >>> ui
222
+ Integral(cos(u)/2, (u, -1, 0))
223
+
224
+ This attempt fails because x = +/-sqrt(u + 1) and the
225
+ sign does not cancel out of the integrand:
226
+
227
+ >>> Integral(cos(x**2 - 1), (x, 0, 1)).transform(x**2 - 1, u)
228
+ Traceback (most recent call last):
229
+ ...
230
+ ValueError:
231
+ The mapping between F(x) and f(u) did not give a unique integrand.
232
+
233
+ transform can do a substitution. Here, the previous
234
+ result is transformed back into the original expression
235
+ using "u-substitution":
236
+
237
+ >>> ui.transform(sqrt(u + 1), x) == i
238
+ True
239
+
240
+ We can accomplish the same with a regular substitution:
241
+
242
+ >>> ui.transform(u, x**2 - 1) == i
243
+ True
244
+
245
+ If the `x` does not contain a symbol of integration then
246
+ the integral will be returned unchanged. Integral `i` does
247
+ not have an integration variable `a` so no change is made:
248
+
249
+ >>> i.transform(a, x) == i
250
+ True
251
+
252
+ When `u` has more than one free symbol the symbol that is
253
+ replacing `x` must be identified by passing `u` as a tuple:
254
+
255
+ >>> Integral(x, (x, 0, 1)).transform(x, (u + a, u))
256
+ Integral(a + u, (u, -a, 1 - a))
257
+ >>> Integral(x, (x, 0, 1)).transform(x, (u + a, a))
258
+ Integral(a + u, (a, -u, 1 - u))
259
+
260
+ See Also
261
+ ========
262
+
263
+ sympy.concrete.expr_with_limits.ExprWithLimits.variables : Lists the integration variables
264
+ as_dummy : Replace integration variables with dummy ones
265
+ """
266
+ d = Dummy('d')
267
+
268
+ xfree = x.free_symbols.intersection(self.variables)
269
+ if len(xfree) > 1:
270
+ raise ValueError(
271
+ 'F(x) can only contain one of: %s' % self.variables)
272
+ xvar = xfree.pop() if xfree else d
273
+
274
+ if xvar not in self.variables:
275
+ return self
276
+
277
+ u = sympify(u)
278
+ if isinstance(u, Expr):
279
+ ufree = u.free_symbols
280
+ if len(ufree) == 0:
281
+ raise ValueError(filldedent('''
282
+ f(u) cannot be a constant'''))
283
+ if len(ufree) > 1:
284
+ raise ValueError(filldedent('''
285
+ When f(u) has more than one free symbol, the one replacing x
286
+ must be identified: pass f(u) as (f(u), u)'''))
287
+ uvar = ufree.pop()
288
+ else:
289
+ u, uvar = u
290
+ if uvar not in u.free_symbols:
291
+ raise ValueError(filldedent('''
292
+ Expecting a tuple (expr, symbol) where symbol identified
293
+ a free symbol in expr, but symbol is not in expr's free
294
+ symbols.'''))
295
+ if not isinstance(uvar, Symbol):
296
+ # This probably never evaluates to True
297
+ raise ValueError(filldedent('''
298
+ Expecting a tuple (expr, symbol) but didn't get
299
+ a symbol; got %s''' % uvar))
300
+
301
+ if x.is_Symbol and u.is_Symbol:
302
+ return self.xreplace({x: u})
303
+
304
+ if not x.is_Symbol and not u.is_Symbol:
305
+ raise ValueError('either x or u must be a symbol')
306
+
307
+ if uvar == xvar:
308
+ return self.transform(x, (u.subs(uvar, d), d)).xreplace({d: uvar})
309
+
310
+ if uvar in self.limits:
311
+ raise ValueError(filldedent('''
312
+ u must contain the same variable as in x
313
+ or a variable that is not already an integration variable'''))
314
+
315
+ from sympy.solvers.solvers import solve
316
+ if not x.is_Symbol:
317
+ F = [x.subs(xvar, d)]
318
+ soln = solve(u - x, xvar, check=False)
319
+ if not soln:
320
+ raise ValueError('no solution for solve(F(x) - f(u), x)')
321
+ f = [fi.subs(uvar, d) for fi in soln]
322
+ else:
323
+ f = [u.subs(uvar, d)]
324
+ from sympy.simplify.simplify import posify
325
+ pdiff, reps = posify(u - x)
326
+ puvar = uvar.subs([(v, k) for k, v in reps.items()])
327
+ soln = [s.subs(reps) for s in solve(pdiff, puvar)]
328
+ if not soln:
329
+ raise ValueError('no solution for solve(F(x) - f(u), u)')
330
+ F = [fi.subs(xvar, d) for fi in soln]
331
+
332
+ newfuncs = {(self.function.subs(xvar, fi)*fi.diff(d)
333
+ ).subs(d, uvar) for fi in f}
334
+ if len(newfuncs) > 1:
335
+ raise ValueError(filldedent('''
336
+ The mapping between F(x) and f(u) did not give
337
+ a unique integrand.'''))
338
+ newfunc = newfuncs.pop()
339
+
340
+ def _calc_limit_1(F, a, b):
341
+ """
342
+ replace d with a, using subs if possible, otherwise limit
343
+ where sign of b is considered
344
+ """
345
+ wok = F.subs(d, a)
346
+ if wok is S.NaN or wok.is_finite is False and a.is_finite:
347
+ return limit(sign(b)*F, d, a)
348
+ return wok
349
+
350
+ def _calc_limit(a, b):
351
+ """
352
+ replace d with a, using subs if possible, otherwise limit
353
+ where sign of b is considered
354
+ """
355
+ avals = list({_calc_limit_1(Fi, a, b) for Fi in F})
356
+ if len(avals) > 1:
357
+ raise ValueError(filldedent('''
358
+ The mapping between F(x) and f(u) did not
359
+ give a unique limit.'''))
360
+ return avals[0]
361
+
362
+ newlimits = []
363
+ for xab in self.limits:
364
+ sym = xab[0]
365
+ if sym == xvar:
366
+ if len(xab) == 3:
367
+ a, b = xab[1:]
368
+ a, b = _calc_limit(a, b), _calc_limit(b, a)
369
+ if fuzzy_bool(a - b > 0):
370
+ a, b = b, a
371
+ newfunc = -newfunc
372
+ newlimits.append((uvar, a, b))
373
+ elif len(xab) == 2:
374
+ a = _calc_limit(xab[1], 1)
375
+ newlimits.append((uvar, a))
376
+ else:
377
+ newlimits.append(uvar)
378
+ else:
379
+ newlimits.append(xab)
380
+
381
+ return self.func(newfunc, *newlimits)
382
+
383
+ def doit(self, **hints):
384
+ """
385
+ Perform the integration using any hints given.
386
+
387
+ Examples
388
+ ========
389
+
390
+ >>> from sympy import Piecewise, S
391
+ >>> from sympy.abc import x, t
392
+ >>> p = x**2 + Piecewise((0, x/t < 0), (1, True))
393
+ >>> p.integrate((t, S(4)/5, 1), (x, -1, 1))
394
+ 1/3
395
+
396
+ See Also
397
+ ========
398
+
399
+ sympy.integrals.trigonometry.trigintegrate
400
+ sympy.integrals.heurisch.heurisch
401
+ sympy.integrals.rationaltools.ratint
402
+ as_sum : Approximate the integral using a sum
403
+ """
404
+ if not hints.get('integrals', True):
405
+ return self
406
+
407
+ deep = hints.get('deep', True)
408
+ meijerg = hints.get('meijerg', None)
409
+ conds = hints.get('conds', 'piecewise')
410
+ risch = hints.get('risch', None)
411
+ heurisch = hints.get('heurisch', None)
412
+ manual = hints.get('manual', None)
413
+ if len(list(filter(None, (manual, meijerg, risch, heurisch)))) > 1:
414
+ raise ValueError("At most one of manual, meijerg, risch, heurisch can be True")
415
+ elif manual:
416
+ meijerg = risch = heurisch = False
417
+ elif meijerg:
418
+ manual = risch = heurisch = False
419
+ elif risch:
420
+ manual = meijerg = heurisch = False
421
+ elif heurisch:
422
+ manual = meijerg = risch = False
423
+ eval_kwargs = {"meijerg": meijerg, "risch": risch, "manual": manual, "heurisch": heurisch,
424
+ "conds": conds}
425
+
426
+ if conds not in ('separate', 'piecewise', 'none'):
427
+ raise ValueError('conds must be one of "separate", "piecewise", '
428
+ '"none", got: %s' % conds)
429
+
430
+ if risch and any(len(xab) > 1 for xab in self.limits):
431
+ raise ValueError('risch=True is only allowed for indefinite integrals.')
432
+
433
+ # check for the trivial zero
434
+ if self.is_zero:
435
+ return S.Zero
436
+
437
+ # hacks to handle integrals of
438
+ # nested summations
439
+ from sympy.concrete.summations import Sum
440
+ if isinstance(self.function, Sum):
441
+ if any(v in self.function.limits[0] for v in self.variables):
442
+ raise ValueError('Limit of the sum cannot be an integration variable.')
443
+ if any(l.is_infinite for l in self.function.limits[0][1:]):
444
+ return self
445
+ _i = self
446
+ _sum = self.function
447
+ return _sum.func(_i.func(_sum.function, *_i.limits).doit(), *_sum.limits).doit()
448
+
449
+ # now compute and check the function
450
+ function = self.function
451
+
452
+ # hack to use a consistent Heaviside(x, 1/2)
453
+ function = function.replace(
454
+ lambda x: isinstance(x, Heaviside) and x.args[1]*2 != 1,
455
+ lambda x: Heaviside(x.args[0]))
456
+
457
+ if deep:
458
+ function = function.doit(**hints)
459
+ if function.is_zero:
460
+ return S.Zero
461
+
462
+ # hacks to handle special cases
463
+ if isinstance(function, MatrixBase):
464
+ return function.applyfunc(
465
+ lambda f: self.func(f, *self.limits).doit(**hints))
466
+
467
+ if isinstance(function, FormalPowerSeries):
468
+ if len(self.limits) > 1:
469
+ raise NotImplementedError
470
+ xab = self.limits[0]
471
+ if len(xab) > 1:
472
+ return function.integrate(xab, **eval_kwargs)
473
+ else:
474
+ return function.integrate(xab[0], **eval_kwargs)
475
+
476
+ # There is no trivial answer and special handling
477
+ # is done so continue
478
+
479
+ # first make sure any definite limits have integration
480
+ # variables with matching assumptions
481
+ reps = {}
482
+ for xab in self.limits:
483
+ if len(xab) != 3:
484
+ # it makes sense to just make
485
+ # all x real but in practice with the
486
+ # current state of integration...this
487
+ # doesn't work out well
488
+ # x = xab[0]
489
+ # if x not in reps and not x.is_real:
490
+ # reps[x] = Dummy(real=True)
491
+ continue
492
+ x, a, b = xab
493
+ l = (a, b)
494
+ if all(i.is_nonnegative for i in l) and not x.is_nonnegative:
495
+ d = Dummy(positive=True)
496
+ elif all(i.is_nonpositive for i in l) and not x.is_nonpositive:
497
+ d = Dummy(negative=True)
498
+ elif all(i.is_real for i in l) and not x.is_real:
499
+ d = Dummy(real=True)
500
+ else:
501
+ d = None
502
+ if d:
503
+ reps[x] = d
504
+ if reps:
505
+ undo = {v: k for k, v in reps.items()}
506
+ did = self.xreplace(reps).doit(**hints)
507
+ if isinstance(did, tuple): # when separate=True
508
+ did = tuple([i.xreplace(undo) for i in did])
509
+ else:
510
+ did = did.xreplace(undo)
511
+ return did
512
+
513
+ # continue with existing assumptions
514
+ undone_limits = []
515
+ # ulj = free symbols of any undone limits' upper and lower limits
516
+ ulj = set()
517
+ for xab in self.limits:
518
+ # compute uli, the free symbols in the
519
+ # Upper and Lower limits of limit I
520
+ if len(xab) == 1:
521
+ uli = set(xab[:1])
522
+ elif len(xab) == 2:
523
+ uli = xab[1].free_symbols
524
+ elif len(xab) == 3:
525
+ uli = xab[1].free_symbols.union(xab[2].free_symbols)
526
+ # this integral can be done as long as there is no blocking
527
+ # limit that has been undone. An undone limit is blocking if
528
+ # it contains an integration variable that is in this limit's
529
+ # upper or lower free symbols or vice versa
530
+ if xab[0] in ulj or any(v[0] in uli for v in undone_limits):
531
+ undone_limits.append(xab)
532
+ ulj.update(uli)
533
+ function = self.func(*([function] + [xab]))
534
+ factored_function = function.factor()
535
+ if not isinstance(factored_function, Integral):
536
+ function = factored_function
537
+ continue
538
+
539
+ if function.has(Abs, sign) and (
540
+ (len(xab) < 3 and all(x.is_extended_real for x in xab)) or
541
+ (len(xab) == 3 and all(x.is_extended_real and not x.is_infinite for
542
+ x in xab[1:]))):
543
+ # some improper integrals are better off with Abs
544
+ xr = Dummy("xr", real=True)
545
+ function = (function.xreplace({xab[0]: xr})
546
+ .rewrite(Piecewise).xreplace({xr: xab[0]}))
547
+ elif function.has(Min, Max):
548
+ function = function.rewrite(Piecewise)
549
+ if (function.has(Piecewise) and
550
+ not isinstance(function, Piecewise)):
551
+ function = piecewise_fold(function)
552
+ if isinstance(function, Piecewise):
553
+ if len(xab) == 1:
554
+ antideriv = function._eval_integral(xab[0],
555
+ **eval_kwargs)
556
+ else:
557
+ antideriv = self._eval_integral(
558
+ function, xab[0], **eval_kwargs)
559
+ else:
560
+ # There are a number of tradeoffs in using the
561
+ # Meijer G method. It can sometimes be a lot faster
562
+ # than other methods, and sometimes slower. And
563
+ # there are certain types of integrals for which it
564
+ # is more likely to work than others. These
565
+ # heuristics are incorporated in deciding what
566
+ # integration methods to try, in what order. See the
567
+ # integrate() docstring for details.
568
+ def try_meijerg(function, xab):
569
+ ret = None
570
+ if len(xab) == 3 and meijerg is not False:
571
+ x, a, b = xab
572
+ try:
573
+ res = meijerint_definite(function, x, a, b)
574
+ except NotImplementedError:
575
+ _debug('NotImplementedError '
576
+ 'from meijerint_definite')
577
+ res = None
578
+ if res is not None:
579
+ f, cond = res
580
+ if conds == 'piecewise':
581
+ u = self.func(function, (x, a, b))
582
+ # if Piecewise modifies cond too
583
+ # much it may not be recognized by
584
+ # _condsimp pattern matching so just
585
+ # turn off all evaluation
586
+ return Piecewise((f, cond), (u, True),
587
+ evaluate=False)
588
+ elif conds == 'separate':
589
+ if len(self.limits) != 1:
590
+ raise ValueError(filldedent('''
591
+ conds=separate not supported in
592
+ multiple integrals'''))
593
+ ret = f, cond
594
+ else:
595
+ ret = f
596
+ return ret
597
+
598
+ meijerg1 = meijerg
599
+ if (meijerg is not False and
600
+ len(xab) == 3 and xab[1].is_extended_real and xab[2].is_extended_real
601
+ and not function.is_Poly and
602
+ (xab[1].has(oo, -oo) or xab[2].has(oo, -oo))):
603
+ ret = try_meijerg(function, xab)
604
+ if ret is not None:
605
+ function = ret
606
+ continue
607
+ meijerg1 = False
608
+ # If the special meijerg code did not succeed in
609
+ # finding a definite integral, then the code using
610
+ # meijerint_indefinite will not either (it might
611
+ # find an antiderivative, but the answer is likely
612
+ # to be nonsensical). Thus if we are requested to
613
+ # only use Meijer G-function methods, we give up at
614
+ # this stage. Otherwise we just disable G-function
615
+ # methods.
616
+ if meijerg1 is False and meijerg is True:
617
+ antideriv = None
618
+ else:
619
+ antideriv = self._eval_integral(
620
+ function, xab[0], **eval_kwargs)
621
+ if antideriv is None and meijerg is True:
622
+ ret = try_meijerg(function, xab)
623
+ if ret is not None:
624
+ function = ret
625
+ continue
626
+
627
+ final = hints.get('final', True)
628
+ # dotit may be iterated but floor terms making atan and acot
629
+ # continuous should only be added in the final round
630
+ if (final and not isinstance(antideriv, Integral) and
631
+ antideriv is not None):
632
+ for atan_term in antideriv.atoms(atan):
633
+ atan_arg = atan_term.args[0]
634
+ # Checking `atan_arg` to be linear combination of `tan` or `cot`
635
+ for tan_part in atan_arg.atoms(tan):
636
+ x1 = Dummy('x1')
637
+ tan_exp1 = atan_arg.subs(tan_part, x1)
638
+ # The coefficient of `tan` should be constant
639
+ coeff = tan_exp1.diff(x1)
640
+ if x1 not in coeff.free_symbols:
641
+ a = tan_part.args[0]
642
+ antideriv = antideriv.subs(atan_term, Add(atan_term,
643
+ sign(coeff)*pi*floor((a-pi/2)/pi)))
644
+ for cot_part in atan_arg.atoms(cot):
645
+ x1 = Dummy('x1')
646
+ cot_exp1 = atan_arg.subs(cot_part, x1)
647
+ # The coefficient of `cot` should be constant
648
+ coeff = cot_exp1.diff(x1)
649
+ if x1 not in coeff.free_symbols:
650
+ a = cot_part.args[0]
651
+ antideriv = antideriv.subs(atan_term, Add(atan_term,
652
+ sign(coeff)*pi*floor((a)/pi)))
653
+
654
+ if antideriv is None:
655
+ undone_limits.append(xab)
656
+ function = self.func(*([function] + [xab])).factor()
657
+ factored_function = function.factor()
658
+ if not isinstance(factored_function, Integral):
659
+ function = factored_function
660
+ continue
661
+ else:
662
+ if len(xab) == 1:
663
+ function = antideriv
664
+ else:
665
+ if len(xab) == 3:
666
+ x, a, b = xab
667
+ elif len(xab) == 2:
668
+ x, b = xab
669
+ a = None
670
+ else:
671
+ raise NotImplementedError
672
+
673
+ if deep:
674
+ if isinstance(a, Basic):
675
+ a = a.doit(**hints)
676
+ if isinstance(b, Basic):
677
+ b = b.doit(**hints)
678
+
679
+ if antideriv.is_Poly:
680
+ gens = list(antideriv.gens)
681
+ gens.remove(x)
682
+
683
+ antideriv = antideriv.as_expr()
684
+
685
+ function = antideriv._eval_interval(x, a, b)
686
+ function = Poly(function, *gens)
687
+ else:
688
+ def is_indef_int(g, x):
689
+ return (isinstance(g, Integral) and
690
+ any(i == (x,) for i in g.limits))
691
+
692
+ def eval_factored(f, x, a, b):
693
+ # _eval_interval for integrals with
694
+ # (constant) factors
695
+ # a single indefinite integral is assumed
696
+ args = []
697
+ for g in Mul.make_args(f):
698
+ if is_indef_int(g, x):
699
+ args.append(g._eval_interval(x, a, b))
700
+ else:
701
+ args.append(g)
702
+ return Mul(*args)
703
+
704
+ integrals, others, piecewises = [], [], []
705
+ for f in Add.make_args(antideriv):
706
+ if any(is_indef_int(g, x)
707
+ for g in Mul.make_args(f)):
708
+ integrals.append(f)
709
+ elif any(isinstance(g, Piecewise)
710
+ for g in Mul.make_args(f)):
711
+ piecewises.append(piecewise_fold(f))
712
+ else:
713
+ others.append(f)
714
+ uneval = Add(*[eval_factored(f, x, a, b)
715
+ for f in integrals])
716
+ try:
717
+ evalued = Add(*others)._eval_interval(x, a, b)
718
+ evalued_pw = piecewise_fold(Add(*piecewises))._eval_interval(x, a, b)
719
+ function = uneval + evalued + evalued_pw
720
+ except NotImplementedError:
721
+ # This can happen if _eval_interval depends in a
722
+ # complicated way on limits that cannot be computed
723
+ undone_limits.append(xab)
724
+ function = self.func(*([function] + [xab]))
725
+ factored_function = function.factor()
726
+ if not isinstance(factored_function, Integral):
727
+ function = factored_function
728
+ return function
729
+
730
+ def _eval_derivative(self, sym):
731
+ """Evaluate the derivative of the current Integral object by
732
+ differentiating under the integral sign [1], using the Fundamental
733
+ Theorem of Calculus [2] when possible.
734
+
735
+ Explanation
736
+ ===========
737
+
738
+ Whenever an Integral is encountered that is equivalent to zero or
739
+ has an integrand that is independent of the variable of integration
740
+ those integrals are performed. All others are returned as Integral
741
+ instances which can be resolved with doit() (provided they are integrable).
742
+
743
+ References
744
+ ==========
745
+
746
+ .. [1] https://en.wikipedia.org/wiki/Differentiation_under_the_integral_sign
747
+ .. [2] https://en.wikipedia.org/wiki/Fundamental_theorem_of_calculus
748
+
749
+ Examples
750
+ ========
751
+
752
+ >>> from sympy import Integral
753
+ >>> from sympy.abc import x, y
754
+ >>> i = Integral(x + y, y, (y, 1, x))
755
+ >>> i.diff(x)
756
+ Integral(x + y, (y, x)) + Integral(1, y, (y, 1, x))
757
+ >>> i.doit().diff(x) == i.diff(x).doit()
758
+ True
759
+ >>> i.diff(y)
760
+ 0
761
+
762
+ The previous must be true since there is no y in the evaluated integral:
763
+
764
+ >>> i.free_symbols
765
+ {x}
766
+ >>> i.doit()
767
+ 2*x**3/3 - x/2 - 1/6
768
+
769
+ """
770
+
771
+ # differentiate under the integral sign; we do not
772
+ # check for regularity conditions (TODO), see issue 4215
773
+
774
+ # get limits and the function
775
+ f, limits = self.function, list(self.limits)
776
+
777
+ # the order matters if variables of integration appear in the limits
778
+ # so work our way in from the outside to the inside.
779
+ limit = limits.pop(-1)
780
+ if len(limit) == 3:
781
+ x, a, b = limit
782
+ elif len(limit) == 2:
783
+ x, b = limit
784
+ a = None
785
+ else:
786
+ a = b = None
787
+ x = limit[0]
788
+
789
+ if limits: # f is the argument to an integral
790
+ f = self.func(f, *tuple(limits))
791
+
792
+ # assemble the pieces
793
+ def _do(f, ab):
794
+ dab_dsym = diff(ab, sym)
795
+ if not dab_dsym:
796
+ return S.Zero
797
+ if isinstance(f, Integral):
798
+ limits = [(x, x) if (len(l) == 1 and l[0] == x) else l
799
+ for l in f.limits]
800
+ f = self.func(f.function, *limits)
801
+ return f.subs(x, ab)*dab_dsym
802
+
803
+ rv = S.Zero
804
+ if b is not None:
805
+ rv += _do(f, b)
806
+ if a is not None:
807
+ rv -= _do(f, a)
808
+ if len(limit) == 1 and sym == x:
809
+ # the dummy variable *is* also the real-world variable
810
+ arg = f
811
+ rv += arg
812
+ else:
813
+ # the dummy variable might match sym but it's
814
+ # only a dummy and the actual variable is determined
815
+ # by the limits, so mask off the variable of integration
816
+ # while differentiating
817
+ u = Dummy('u')
818
+ arg = f.subs(x, u).diff(sym).subs(u, x)
819
+ if arg:
820
+ rv += self.func(arg, (x, a, b))
821
+ return rv
822
+
823
+ def _eval_integral(self, f, x, meijerg=None, risch=None, manual=None,
824
+ heurisch=None, conds='piecewise',final=None):
825
+ """
826
+ Calculate the anti-derivative to the function f(x).
827
+
828
+ Explanation
829
+ ===========
830
+
831
+ The following algorithms are applied (roughly in this order):
832
+
833
+ 1. Simple heuristics (based on pattern matching and integral table):
834
+
835
+ - most frequently used functions (e.g. polynomials, products of
836
+ trig functions)
837
+
838
+ 2. Integration of rational functions:
839
+
840
+ - A complete algorithm for integrating rational functions is
841
+ implemented (the Lazard-Rioboo-Trager algorithm). The algorithm
842
+ also uses the partial fraction decomposition algorithm
843
+ implemented in apart() as a preprocessor to make this process
844
+ faster. Note that the integral of a rational function is always
845
+ elementary, but in general, it may include a RootSum.
846
+
847
+ 3. Full Risch algorithm:
848
+
849
+ - The Risch algorithm is a complete decision
850
+ procedure for integrating elementary functions, which means that
851
+ given any elementary function, it will either compute an
852
+ elementary antiderivative, or else prove that none exists.
853
+ Currently, part of transcendental case is implemented, meaning
854
+ elementary integrals containing exponentials, logarithms, and
855
+ (soon!) trigonometric functions can be computed. The algebraic
856
+ case, e.g., functions containing roots, is much more difficult
857
+ and is not implemented yet.
858
+
859
+ - If the routine fails (because the integrand is not elementary, or
860
+ because a case is not implemented yet), it continues on to the
861
+ next algorithms below. If the routine proves that the integrals
862
+ is nonelementary, it still moves on to the algorithms below,
863
+ because we might be able to find a closed-form solution in terms
864
+ of special functions. If risch=True, however, it will stop here.
865
+
866
+ 4. The Meijer G-Function algorithm:
867
+
868
+ - This algorithm works by first rewriting the integrand in terms of
869
+ very general Meijer G-Function (meijerg in SymPy), integrating
870
+ it, and then rewriting the result back, if possible. This
871
+ algorithm is particularly powerful for definite integrals (which
872
+ is actually part of a different method of Integral), since it can
873
+ compute closed-form solutions of definite integrals even when no
874
+ closed-form indefinite integral exists. But it also is capable
875
+ of computing many indefinite integrals as well.
876
+
877
+ - Another advantage of this method is that it can use some results
878
+ about the Meijer G-Function to give a result in terms of a
879
+ Piecewise expression, which allows to express conditionally
880
+ convergent integrals.
881
+
882
+ - Setting meijerg=True will cause integrate() to use only this
883
+ method.
884
+
885
+ 5. The "manual integration" algorithm:
886
+
887
+ - This algorithm tries to mimic how a person would find an
888
+ antiderivative by hand, for example by looking for a
889
+ substitution or applying integration by parts. This algorithm
890
+ does not handle as many integrands but can return results in a
891
+ more familiar form.
892
+
893
+ - Sometimes this algorithm can evaluate parts of an integral; in
894
+ this case integrate() will try to evaluate the rest of the
895
+ integrand using the other methods here.
896
+
897
+ - Setting manual=True will cause integrate() to use only this
898
+ method.
899
+
900
+ 6. The Heuristic Risch algorithm:
901
+
902
+ - This is a heuristic version of the Risch algorithm, meaning that
903
+ it is not deterministic. This is tried as a last resort because
904
+ it can be very slow. It is still used because not enough of the
905
+ full Risch algorithm is implemented, so that there are still some
906
+ integrals that can only be computed using this method. The goal
907
+ is to implement enough of the Risch and Meijer G-function methods
908
+ so that this can be deleted.
909
+
910
+ Setting heurisch=True will cause integrate() to use only this
911
+ method. Set heurisch=False to not use it.
912
+
913
+ """
914
+
915
+ from sympy.integrals.risch import risch_integrate, NonElementaryIntegral
916
+ from sympy.integrals.manualintegrate import manualintegrate
917
+
918
+ if risch:
919
+ try:
920
+ return risch_integrate(f, x, conds=conds)
921
+ except NotImplementedError:
922
+ return None
923
+
924
+ if manual:
925
+ try:
926
+ result = manualintegrate(f, x)
927
+ if result is not None and result.func != Integral:
928
+ return result
929
+ except (ValueError, PolynomialError):
930
+ pass
931
+
932
+ eval_kwargs = {"meijerg": meijerg, "risch": risch, "manual": manual,
933
+ "heurisch": heurisch, "conds": conds}
934
+
935
+ # if it is a poly(x) then let the polynomial integrate itself (fast)
936
+ #
937
+ # It is important to make this check first, otherwise the other code
938
+ # will return a SymPy expression instead of a Polynomial.
939
+ #
940
+ # see Polynomial for details.
941
+ if isinstance(f, Poly) and not (manual or meijerg or risch):
942
+ # Note: this is deprecated, but the deprecation warning is already
943
+ # issued in the Integral constructor.
944
+ return f.integrate(x)
945
+
946
+ # Piecewise antiderivatives need to call special integrate.
947
+ if isinstance(f, Piecewise):
948
+ return f.piecewise_integrate(x, **eval_kwargs)
949
+
950
+ # let's cut it short if `f` does not depend on `x`; if
951
+ # x is only a dummy, that will be handled below
952
+ if not f.has(x):
953
+ return f*x
954
+
955
+ # try to convert to poly(x) and then integrate if successful (fast)
956
+ poly = f.as_poly(x)
957
+ if poly is not None and not (manual or meijerg or risch):
958
+ return poly.integrate().as_expr()
959
+
960
+ if risch is not False:
961
+ try:
962
+ result, i = risch_integrate(f, x, separate_integral=True,
963
+ conds=conds)
964
+ except NotImplementedError:
965
+ pass
966
+ else:
967
+ if i:
968
+ # There was a nonelementary integral. Try integrating it.
969
+
970
+ # if no part of the NonElementaryIntegral is integrated by
971
+ # the Risch algorithm, then use the original function to
972
+ # integrate, instead of re-written one
973
+ if result == 0:
974
+ return NonElementaryIntegral(f, x).doit(risch=False)
975
+ else:
976
+ return result + i.doit(risch=False)
977
+ else:
978
+ return result
979
+
980
+ # since Integral(f=g1+g2+...) == Integral(g1) + Integral(g2) + ...
981
+ # we are going to handle Add terms separately,
982
+ # if `f` is not Add -- we only have one term
983
+
984
+ # Note that in general, this is a bad idea, because Integral(g1) +
985
+ # Integral(g2) might not be computable, even if Integral(g1 + g2) is.
986
+ # For example, Integral(x**x + x**x*log(x)). But many heuristics only
987
+ # work term-wise. So we compute this step last, after trying
988
+ # risch_integrate. We also try risch_integrate again in this loop,
989
+ # because maybe the integral is a sum of an elementary part and a
990
+ # nonelementary part (like erf(x) + exp(x)). risch_integrate() is
991
+ # quite fast, so this is acceptable.
992
+ from sympy.simplify.fu import sincos_to_sum
993
+ parts = []
994
+ args = Add.make_args(f)
995
+ for g in args:
996
+ coeff, g = g.as_independent(x)
997
+
998
+ # g(x) = const
999
+ if g is S.One and not meijerg:
1000
+ parts.append(coeff*x)
1001
+ continue
1002
+
1003
+ # g(x) = expr + O(x**n)
1004
+ order_term = g.getO()
1005
+
1006
+ if order_term is not None:
1007
+ h = self._eval_integral(g.removeO(), x, **eval_kwargs)
1008
+
1009
+ if h is not None:
1010
+ h_order_expr = self._eval_integral(order_term.expr, x, **eval_kwargs)
1011
+
1012
+ if h_order_expr is not None:
1013
+ h_order_term = order_term.func(
1014
+ h_order_expr, *order_term.variables)
1015
+ parts.append(coeff*(h + h_order_term))
1016
+ continue
1017
+
1018
+ # NOTE: if there is O(x**n) and we fail to integrate then
1019
+ # there is no point in trying other methods because they
1020
+ # will fail, too.
1021
+ return None
1022
+
1023
+ # c
1024
+ # g(x) = (a*x+b)
1025
+ if g.is_Pow and not g.exp.has(x) and not meijerg:
1026
+ a = Wild('a', exclude=[x])
1027
+ b = Wild('b', exclude=[x])
1028
+
1029
+ M = g.base.match(a*x + b)
1030
+
1031
+ if M is not None:
1032
+ if g.exp == -1:
1033
+ h = log(g.base)
1034
+ elif conds != 'piecewise':
1035
+ h = g.base**(g.exp + 1) / (g.exp + 1)
1036
+ else:
1037
+ h1 = log(g.base)
1038
+ h2 = g.base**(g.exp + 1) / (g.exp + 1)
1039
+ h = Piecewise((h2, Ne(g.exp, -1)), (h1, True))
1040
+
1041
+ parts.append(coeff * h / M[a])
1042
+ continue
1043
+
1044
+ # poly(x)
1045
+ # g(x) = -------
1046
+ # poly(x)
1047
+ if g.is_rational_function(x) and not (manual or meijerg or risch):
1048
+ parts.append(coeff * ratint(g, x))
1049
+ continue
1050
+
1051
+ if not (manual or meijerg or risch):
1052
+ # g(x) = Mul(trig)
1053
+ h = trigintegrate(g, x, conds=conds)
1054
+ if h is not None:
1055
+ parts.append(coeff * h)
1056
+ continue
1057
+
1058
+ # g(x) has at least a DiracDelta term
1059
+ h = deltaintegrate(g, x)
1060
+ if h is not None:
1061
+ parts.append(coeff * h)
1062
+ continue
1063
+
1064
+ from .singularityfunctions import singularityintegrate
1065
+ # g(x) has at least a Singularity Function term
1066
+ h = singularityintegrate(g, x)
1067
+ if h is not None:
1068
+ parts.append(coeff * h)
1069
+ continue
1070
+
1071
+ # Try risch again.
1072
+ if risch is not False:
1073
+ try:
1074
+ h, i = risch_integrate(g, x,
1075
+ separate_integral=True, conds=conds)
1076
+ except NotImplementedError:
1077
+ h = None
1078
+ else:
1079
+ if i:
1080
+ h = h + i.doit(risch=False)
1081
+
1082
+ parts.append(coeff*h)
1083
+ continue
1084
+
1085
+ # fall back to heurisch
1086
+ if heurisch is not False:
1087
+ from sympy.integrals.heurisch import (heurisch as heurisch_,
1088
+ heurisch_wrapper)
1089
+ try:
1090
+ if conds == 'piecewise':
1091
+ h = heurisch_wrapper(g, x, hints=[])
1092
+ else:
1093
+ h = heurisch_(g, x, hints=[])
1094
+ except PolynomialError:
1095
+ # XXX: this exception means there is a bug in the
1096
+ # implementation of heuristic Risch integration
1097
+ # algorithm.
1098
+ h = None
1099
+ else:
1100
+ h = None
1101
+
1102
+ if meijerg is not False and h is None:
1103
+ # rewrite using G functions
1104
+ try:
1105
+ h = meijerint_indefinite(g, x)
1106
+ except NotImplementedError:
1107
+ _debug('NotImplementedError from meijerint_definite')
1108
+ if h is not None:
1109
+ parts.append(coeff * h)
1110
+ continue
1111
+
1112
+ if h is None and manual is not False:
1113
+ try:
1114
+ result = manualintegrate(g, x)
1115
+ if result is not None and not isinstance(result, Integral):
1116
+ if result.has(Integral) and not manual:
1117
+ # Try to have other algorithms do the integrals
1118
+ # manualintegrate can't handle,
1119
+ # unless we were asked to use manual only.
1120
+ # Keep the rest of eval_kwargs in case another
1121
+ # method was set to False already
1122
+ new_eval_kwargs = eval_kwargs
1123
+ new_eval_kwargs["manual"] = False
1124
+ new_eval_kwargs["final"] = False
1125
+ result = result.func(*[
1126
+ arg.doit(**new_eval_kwargs) if
1127
+ arg.has(Integral) else arg
1128
+ for arg in result.args
1129
+ ]).expand(multinomial=False,
1130
+ log=False,
1131
+ power_exp=False,
1132
+ power_base=False)
1133
+ if not result.has(Integral):
1134
+ parts.append(coeff * result)
1135
+ continue
1136
+ except (ValueError, PolynomialError):
1137
+ # can't handle some SymPy expressions
1138
+ pass
1139
+
1140
+ # if we failed maybe it was because we had
1141
+ # a product that could have been expanded,
1142
+ # so let's try an expansion of the whole
1143
+ # thing before giving up; we don't try this
1144
+ # at the outset because there are things
1145
+ # that cannot be solved unless they are
1146
+ # NOT expanded e.g., x**x*(1+log(x)). There
1147
+ # should probably be a checker somewhere in this
1148
+ # routine to look for such cases and try to do
1149
+ # collection on the expressions if they are already
1150
+ # in an expanded form
1151
+ if not h and len(args) == 1:
1152
+ f = sincos_to_sum(f).expand(mul=True, deep=False)
1153
+ if f.is_Add:
1154
+ # Note: risch will be identical on the expanded
1155
+ # expression, but maybe it will be able to pick out parts,
1156
+ # like x*(exp(x) + erf(x)).
1157
+ return self._eval_integral(f, x, **eval_kwargs)
1158
+
1159
+ if h is not None:
1160
+ parts.append(coeff * h)
1161
+ else:
1162
+ return None
1163
+
1164
+ return Add(*parts)
1165
+
1166
+ def _eval_lseries(self, x, logx=None, cdir=0):
1167
+ expr = self.as_dummy()
1168
+ symb = x
1169
+ for l in expr.limits:
1170
+ if x in l[1:]:
1171
+ symb = l[0]
1172
+ break
1173
+ for term in expr.function.lseries(symb, logx):
1174
+ yield integrate(term, *expr.limits)
1175
+
1176
+ def _eval_nseries(self, x, n, logx=None, cdir=0):
1177
+ symb = x
1178
+ for l in self.limits:
1179
+ if x in l[1:]:
1180
+ symb = l[0]
1181
+ break
1182
+ terms, order = self.function.nseries(
1183
+ x=symb, n=n, logx=logx).as_coeff_add(Order)
1184
+ order = [o.subs(symb, x) for o in order]
1185
+ return integrate(terms, *self.limits) + Add(*order)*x
1186
+
1187
+ def _eval_as_leading_term(self, x, logx, cdir):
1188
+ series_gen = self.args[0].lseries(x)
1189
+ for leading_term in series_gen:
1190
+ if leading_term != 0:
1191
+ break
1192
+ return integrate(leading_term, *self.args[1:])
1193
+
1194
+ def _eval_simplify(self, **kwargs):
1195
+ expr = factor_terms(self)
1196
+ if isinstance(expr, Integral):
1197
+ from sympy.simplify.simplify import simplify
1198
+ return expr.func(*[simplify(i, **kwargs) for i in expr.args])
1199
+ return expr.simplify(**kwargs)
1200
+
1201
+ def as_sum(self, n=None, method="midpoint", evaluate=True):
1202
+ """
1203
+ Approximates a definite integral by a sum.
1204
+
1205
+ Parameters
1206
+ ==========
1207
+
1208
+ n :
1209
+ The number of subintervals to use, optional.
1210
+ method :
1211
+ One of: 'left', 'right', 'midpoint', 'trapezoid'.
1212
+ evaluate : bool
1213
+ If False, returns an unevaluated Sum expression. The default
1214
+ is True, evaluate the sum.
1215
+
1216
+ Notes
1217
+ =====
1218
+
1219
+ These methods of approximate integration are described in [1].
1220
+
1221
+ Examples
1222
+ ========
1223
+
1224
+ >>> from sympy import Integral, sin, sqrt
1225
+ >>> from sympy.abc import x, n
1226
+ >>> e = Integral(sin(x), (x, 3, 7))
1227
+ >>> e
1228
+ Integral(sin(x), (x, 3, 7))
1229
+
1230
+ For demonstration purposes, this interval will only be split into 2
1231
+ regions, bounded by [3, 5] and [5, 7].
1232
+
1233
+ The left-hand rule uses function evaluations at the left of each
1234
+ interval:
1235
+
1236
+ >>> e.as_sum(2, 'left')
1237
+ 2*sin(5) + 2*sin(3)
1238
+
1239
+ The midpoint rule uses evaluations at the center of each interval:
1240
+
1241
+ >>> e.as_sum(2, 'midpoint')
1242
+ 2*sin(4) + 2*sin(6)
1243
+
1244
+ The right-hand rule uses function evaluations at the right of each
1245
+ interval:
1246
+
1247
+ >>> e.as_sum(2, 'right')
1248
+ 2*sin(5) + 2*sin(7)
1249
+
1250
+ The trapezoid rule uses function evaluations on both sides of the
1251
+ intervals. This is equivalent to taking the average of the left and
1252
+ right hand rule results:
1253
+
1254
+ >>> s = e.as_sum(2, 'trapezoid')
1255
+ >>> s
1256
+ 2*sin(5) + sin(3) + sin(7)
1257
+ >>> (e.as_sum(2, 'left') + e.as_sum(2, 'right'))/2 == s
1258
+ True
1259
+
1260
+ Here, the discontinuity at x = 0 can be avoided by using the
1261
+ midpoint or right-hand method:
1262
+
1263
+ >>> e = Integral(1/sqrt(x), (x, 0, 1))
1264
+ >>> e.as_sum(5).n(4)
1265
+ 1.730
1266
+ >>> e.as_sum(10).n(4)
1267
+ 1.809
1268
+ >>> e.doit().n(4) # the actual value is 2
1269
+ 2.000
1270
+
1271
+ The left- or trapezoid method will encounter the discontinuity and
1272
+ return infinity:
1273
+
1274
+ >>> e.as_sum(5, 'left')
1275
+ zoo
1276
+
1277
+ The number of intervals can be symbolic. If omitted, a dummy symbol
1278
+ will be used for it.
1279
+
1280
+ >>> e = Integral(x**2, (x, 0, 2))
1281
+ >>> e.as_sum(n, 'right').expand()
1282
+ 8/3 + 4/n + 4/(3*n**2)
1283
+
1284
+ This shows that the midpoint rule is more accurate, as its error
1285
+ term decays as the square of n:
1286
+
1287
+ >>> e.as_sum(method='midpoint').expand()
1288
+ 8/3 - 2/(3*_n**2)
1289
+
1290
+ A symbolic sum is returned with evaluate=False:
1291
+
1292
+ >>> e.as_sum(n, 'midpoint', evaluate=False)
1293
+ 2*Sum((2*_k/n - 1/n)**2, (_k, 1, n))/n
1294
+
1295
+ See Also
1296
+ ========
1297
+
1298
+ Integral.doit : Perform the integration using any hints
1299
+
1300
+ References
1301
+ ==========
1302
+
1303
+ .. [1] https://en.wikipedia.org/wiki/Riemann_sum#Riemann_summation_methods
1304
+ """
1305
+
1306
+ from sympy.concrete.summations import Sum
1307
+ limits = self.limits
1308
+ if len(limits) > 1:
1309
+ raise NotImplementedError(
1310
+ "Multidimensional midpoint rule not implemented yet")
1311
+ else:
1312
+ limit = limits[0]
1313
+ if (len(limit) != 3 or limit[1].is_finite is False or
1314
+ limit[2].is_finite is False):
1315
+ raise ValueError("Expecting a definite integral over "
1316
+ "a finite interval.")
1317
+ if n is None:
1318
+ n = Dummy('n', integer=True, positive=True)
1319
+ else:
1320
+ n = sympify(n)
1321
+ if (n.is_positive is False or n.is_integer is False or
1322
+ n.is_finite is False):
1323
+ raise ValueError("n must be a positive integer, got %s" % n)
1324
+ x, a, b = limit
1325
+ dx = (b - a)/n
1326
+ k = Dummy('k', integer=True, positive=True)
1327
+ f = self.function
1328
+
1329
+ if method == "left":
1330
+ result = dx*Sum(f.subs(x, a + (k-1)*dx), (k, 1, n))
1331
+ elif method == "right":
1332
+ result = dx*Sum(f.subs(x, a + k*dx), (k, 1, n))
1333
+ elif method == "midpoint":
1334
+ result = dx*Sum(f.subs(x, a + k*dx - dx/2), (k, 1, n))
1335
+ elif method == "trapezoid":
1336
+ result = dx*((f.subs(x, a) + f.subs(x, b))/2 +
1337
+ Sum(f.subs(x, a + k*dx), (k, 1, n - 1)))
1338
+ else:
1339
+ raise ValueError("Unknown method %s" % method)
1340
+ return result.doit() if evaluate else result
1341
+
1342
+ def principal_value(self, **kwargs):
1343
+ """
1344
+ Compute the Cauchy Principal Value of the definite integral of a real function in the given interval
1345
+ on the real axis.
1346
+
1347
+ Explanation
1348
+ ===========
1349
+
1350
+ In mathematics, the Cauchy principal value, is a method for assigning values to certain improper
1351
+ integrals which would otherwise be undefined.
1352
+
1353
+ Examples
1354
+ ========
1355
+
1356
+ >>> from sympy import Integral, oo
1357
+ >>> from sympy.abc import x
1358
+ >>> Integral(x+1, (x, -oo, oo)).principal_value()
1359
+ oo
1360
+ >>> f = 1 / (x**3)
1361
+ >>> Integral(f, (x, -oo, oo)).principal_value()
1362
+ 0
1363
+ >>> Integral(f, (x, -10, 10)).principal_value()
1364
+ 0
1365
+ >>> Integral(f, (x, -10, oo)).principal_value() + Integral(f, (x, -oo, 10)).principal_value()
1366
+ 0
1367
+
1368
+ References
1369
+ ==========
1370
+
1371
+ .. [1] https://en.wikipedia.org/wiki/Cauchy_principal_value
1372
+ .. [2] https://mathworld.wolfram.com/CauchyPrincipalValue.html
1373
+ """
1374
+ if len(self.limits) != 1 or len(list(self.limits[0])) != 3:
1375
+ raise ValueError("You need to insert a variable, lower_limit, and upper_limit correctly to calculate "
1376
+ "cauchy's principal value")
1377
+ x, a, b = self.limits[0]
1378
+ if not (a.is_comparable and b.is_comparable and a <= b):
1379
+ raise ValueError("The lower_limit must be smaller than or equal to the upper_limit to calculate "
1380
+ "cauchy's principal value. Also, a and b need to be comparable.")
1381
+ if a == b:
1382
+ return S.Zero
1383
+
1384
+ from sympy.calculus.singularities import singularities
1385
+
1386
+ r = Dummy('r')
1387
+ f = self.function
1388
+ singularities_list = [s for s in singularities(f, x) if s.is_comparable and a <= s <= b]
1389
+ for i in singularities_list:
1390
+ if i in (a, b):
1391
+ raise ValueError(
1392
+ 'The principal value is not defined in the given interval due to singularity at %d.' % (i))
1393
+ F = integrate(f, x, **kwargs)
1394
+ if F.has(Integral):
1395
+ return self
1396
+ if a is -oo and b is oo:
1397
+ I = limit(F - F.subs(x, -x), x, oo)
1398
+ else:
1399
+ I = limit(F, x, b, '-') - limit(F, x, a, '+')
1400
+ for s in singularities_list:
1401
+ I += limit(((F.subs(x, s - r)) - F.subs(x, s + r)), r, 0, '+')
1402
+ return I
1403
+
1404
+
1405
+
1406
+ def integrate(*args, meijerg=None, conds='piecewise', risch=None, heurisch=None, manual=None, **kwargs):
1407
+ """integrate(f, var, ...)
1408
+
1409
+ .. deprecated:: 1.6
1410
+
1411
+ Using ``integrate()`` with :class:`~.Poly` is deprecated. Use
1412
+ :meth:`.Poly.integrate` instead. See :ref:`deprecated-integrate-poly`.
1413
+
1414
+ Explanation
1415
+ ===========
1416
+
1417
+ Compute definite or indefinite integral of one or more variables
1418
+ using Risch-Norman algorithm and table lookup. This procedure is
1419
+ able to handle elementary algebraic and transcendental functions
1420
+ and also a huge class of special functions, including Airy,
1421
+ Bessel, Whittaker and Lambert.
1422
+
1423
+ var can be:
1424
+
1425
+ - a symbol -- indefinite integration
1426
+ - a tuple (symbol, a) -- indefinite integration with result
1427
+ given with ``a`` replacing ``symbol``
1428
+ - a tuple (symbol, a, b) -- definite integration
1429
+
1430
+ Several variables can be specified, in which case the result is
1431
+ multiple integration. (If var is omitted and the integrand is
1432
+ univariate, the indefinite integral in that variable will be performed.)
1433
+
1434
+ Indefinite integrals are returned without terms that are independent
1435
+ of the integration variables. (see examples)
1436
+
1437
+ Definite improper integrals often entail delicate convergence
1438
+ conditions. Pass conds='piecewise', 'separate' or 'none' to have
1439
+ these returned, respectively, as a Piecewise function, as a separate
1440
+ result (i.e. result will be a tuple), or not at all (default is
1441
+ 'piecewise').
1442
+
1443
+ **Strategy**
1444
+
1445
+ SymPy uses various approaches to definite integration. One method is to
1446
+ find an antiderivative for the integrand, and then use the fundamental
1447
+ theorem of calculus. Various functions are implemented to integrate
1448
+ polynomial, rational and trigonometric functions, and integrands
1449
+ containing DiracDelta terms.
1450
+
1451
+ SymPy also implements the part of the Risch algorithm, which is a decision
1452
+ procedure for integrating elementary functions, i.e., the algorithm can
1453
+ either find an elementary antiderivative, or prove that one does not
1454
+ exist. There is also a (very successful, albeit somewhat slow) general
1455
+ implementation of the heuristic Risch algorithm. This algorithm will
1456
+ eventually be phased out as more of the full Risch algorithm is
1457
+ implemented. See the docstring of Integral._eval_integral() for more
1458
+ details on computing the antiderivative using algebraic methods.
1459
+
1460
+ The option risch=True can be used to use only the (full) Risch algorithm.
1461
+ This is useful if you want to know if an elementary function has an
1462
+ elementary antiderivative. If the indefinite Integral returned by this
1463
+ function is an instance of NonElementaryIntegral, that means that the
1464
+ Risch algorithm has proven that integral to be non-elementary. Note that
1465
+ by default, additional methods (such as the Meijer G method outlined
1466
+ below) are tried on these integrals, as they may be expressible in terms
1467
+ of special functions, so if you only care about elementary answers, use
1468
+ risch=True. Also note that an unevaluated Integral returned by this
1469
+ function is not necessarily a NonElementaryIntegral, even with risch=True,
1470
+ as it may just be an indication that the particular part of the Risch
1471
+ algorithm needed to integrate that function is not yet implemented.
1472
+
1473
+ Another family of strategies comes from re-writing the integrand in
1474
+ terms of so-called Meijer G-functions. Indefinite integrals of a
1475
+ single G-function can always be computed, and the definite integral
1476
+ of a product of two G-functions can be computed from zero to
1477
+ infinity. Various strategies are implemented to rewrite integrands
1478
+ as G-functions, and use this information to compute integrals (see
1479
+ the ``meijerint`` module).
1480
+
1481
+ The option manual=True can be used to use only an algorithm that tries
1482
+ to mimic integration by hand. This algorithm does not handle as many
1483
+ integrands as the other algorithms implemented but may return results in
1484
+ a more familiar form. The ``manualintegrate`` module has functions that
1485
+ return the steps used (see the module docstring for more information).
1486
+
1487
+ In general, the algebraic methods work best for computing
1488
+ antiderivatives of (possibly complicated) combinations of elementary
1489
+ functions. The G-function methods work best for computing definite
1490
+ integrals from zero to infinity of moderately complicated
1491
+ combinations of special functions, or indefinite integrals of very
1492
+ simple combinations of special functions.
1493
+
1494
+ The strategy employed by the integration code is as follows:
1495
+
1496
+ - If computing a definite integral, and both limits are real,
1497
+ and at least one limit is +- oo, try the G-function method of
1498
+ definite integration first.
1499
+
1500
+ - Try to find an antiderivative, using all available methods, ordered
1501
+ by performance (that is try fastest method first, slowest last; in
1502
+ particular polynomial integration is tried first, Meijer
1503
+ G-functions second to last, and heuristic Risch last).
1504
+
1505
+ - If still not successful, try G-functions irrespective of the
1506
+ limits.
1507
+
1508
+ The option meijerg=True, False, None can be used to, respectively:
1509
+ always use G-function methods and no others, never use G-function
1510
+ methods, or use all available methods (in order as described above).
1511
+ It defaults to None.
1512
+
1513
+ Examples
1514
+ ========
1515
+
1516
+ >>> from sympy import integrate, log, exp, oo
1517
+ >>> from sympy.abc import a, x, y
1518
+
1519
+ >>> integrate(x*y, x)
1520
+ x**2*y/2
1521
+
1522
+ >>> integrate(log(x), x)
1523
+ x*log(x) - x
1524
+
1525
+ >>> integrate(log(x), (x, 1, a))
1526
+ a*log(a) - a + 1
1527
+
1528
+ >>> integrate(x)
1529
+ x**2/2
1530
+
1531
+ Terms that are independent of x are dropped by indefinite integration:
1532
+
1533
+ >>> from sympy import sqrt
1534
+ >>> integrate(sqrt(1 + x), (x, 0, x))
1535
+ 2*(x + 1)**(3/2)/3 - 2/3
1536
+ >>> integrate(sqrt(1 + x), x)
1537
+ 2*(x + 1)**(3/2)/3
1538
+
1539
+ >>> integrate(x*y)
1540
+ Traceback (most recent call last):
1541
+ ...
1542
+ ValueError: specify integration variables to integrate x*y
1543
+
1544
+ Note that ``integrate(x)`` syntax is meant only for convenience
1545
+ in interactive sessions and should be avoided in library code.
1546
+
1547
+ >>> integrate(x**a*exp(-x), (x, 0, oo)) # same as conds='piecewise'
1548
+ Piecewise((gamma(a + 1), re(a) > -1),
1549
+ (Integral(x**a*exp(-x), (x, 0, oo)), True))
1550
+
1551
+ >>> integrate(x**a*exp(-x), (x, 0, oo), conds='none')
1552
+ gamma(a + 1)
1553
+
1554
+ >>> integrate(x**a*exp(-x), (x, 0, oo), conds='separate')
1555
+ (gamma(a + 1), re(a) > -1)
1556
+
1557
+ See Also
1558
+ ========
1559
+
1560
+ Integral, Integral.doit
1561
+
1562
+ """
1563
+ doit_flags = {
1564
+ 'deep': False,
1565
+ 'meijerg': meijerg,
1566
+ 'conds': conds,
1567
+ 'risch': risch,
1568
+ 'heurisch': heurisch,
1569
+ 'manual': manual
1570
+ }
1571
+
1572
+ integral = Integral(*args, **kwargs)
1573
+
1574
+ if isinstance(integral, Integral):
1575
+ return integral.doit(**doit_flags)
1576
+ else:
1577
+ new_args = [a.doit(**doit_flags) if isinstance(a, Integral) else a
1578
+ for a in integral.args]
1579
+ return integral.func(*new_args)
1580
+
1581
+ def line_integrate(field, curve, vars):
1582
+ """line_integrate(field, Curve, variables)
1583
+
1584
+ Compute the line integral.
1585
+
1586
+ Examples
1587
+ ========
1588
+
1589
+ >>> from sympy import Curve, line_integrate, E, ln
1590
+ >>> from sympy.abc import x, y, t
1591
+ >>> C = Curve([E**t + 1, E**t - 1], (t, 0, ln(2)))
1592
+ >>> line_integrate(x + y, C, [x, y])
1593
+ 3*sqrt(2)
1594
+
1595
+ See Also
1596
+ ========
1597
+
1598
+ sympy.integrals.integrals.integrate, Integral
1599
+ """
1600
+ from sympy.geometry import Curve
1601
+ F = sympify(field)
1602
+ if not F:
1603
+ raise ValueError(
1604
+ "Expecting function specifying field as first argument.")
1605
+ if not isinstance(curve, Curve):
1606
+ raise ValueError("Expecting Curve entity as second argument.")
1607
+ if not is_sequence(vars):
1608
+ raise ValueError("Expecting ordered iterable for variables.")
1609
+ if len(curve.functions) != len(vars):
1610
+ raise ValueError("Field variable size does not match curve dimension.")
1611
+
1612
+ if curve.parameter in vars:
1613
+ raise ValueError("Curve parameter clashes with field parameters.")
1614
+
1615
+ # Calculate derivatives for line parameter functions
1616
+ # F(r) -> F(r(t)) and finally F(r(t)*r'(t))
1617
+ Ft = F
1618
+ dldt = 0
1619
+ for i, var in enumerate(vars):
1620
+ _f = curve.functions[i]
1621
+ _dn = diff(_f, curve.parameter)
1622
+ # ...arc length
1623
+ dldt = dldt + (_dn * _dn)
1624
+ Ft = Ft.subs(var, _f)
1625
+ Ft = Ft * sqrt(dldt)
1626
+
1627
+ integral = Integral(Ft, curve.limits).doit(deep=False)
1628
+ return integral
1629
+
1630
+
1631
+ ### Property function dispatching ###
1632
+
1633
+ @shape.register(Integral)
1634
+ def _(expr):
1635
+ return shape(expr.function)
1636
+
1637
+ # Delayed imports
1638
+ from .deltafunctions import deltaintegrate
1639
+ from .meijerint import meijerint_definite, meijerint_indefinite, _debug
1640
+ from .trigonometry import trigintegrate
.venv/lib/python3.12/site-packages/sympy/integrals/intpoly.py ADDED
@@ -0,0 +1,1302 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ """
2
+ Module to implement integration of uni/bivariate polynomials over
3
+ 2D Polytopes and uni/bi/trivariate polynomials over 3D Polytopes.
4
+
5
+ Uses evaluation techniques as described in Chin et al. (2015) [1].
6
+
7
+
8
+ References
9
+ ===========
10
+
11
+ .. [1] Chin, Eric B., Jean B. Lasserre, and N. Sukumar. "Numerical integration
12
+ of homogeneous functions on convex and nonconvex polygons and polyhedra."
13
+ Computational Mechanics 56.6 (2015): 967-981
14
+
15
+ PDF link : http://dilbert.engr.ucdavis.edu/~suku/quadrature/cls-integration.pdf
16
+ """
17
+
18
+ from functools import cmp_to_key
19
+
20
+ from sympy.abc import x, y, z
21
+ from sympy.core import S, diff, Expr, Symbol
22
+ from sympy.core.sympify import _sympify
23
+ from sympy.geometry import Segment2D, Polygon, Point, Point2D
24
+ from sympy.polys.polytools import LC, gcd_list, degree_list, Poly
25
+ from sympy.simplify.simplify import nsimplify
26
+
27
+
28
+ def polytope_integrate(poly, expr=None, *, clockwise=False, max_degree=None):
29
+ """Integrates polynomials over 2/3-Polytopes.
30
+
31
+ Explanation
32
+ ===========
33
+
34
+ This function accepts the polytope in ``poly`` and the function in ``expr``
35
+ (uni/bi/trivariate polynomials are implemented) and returns
36
+ the exact integral of ``expr`` over ``poly``.
37
+
38
+ Parameters
39
+ ==========
40
+
41
+ poly : The input Polygon.
42
+
43
+ expr : The input polynomial.
44
+
45
+ clockwise : Binary value to sort input points of 2-Polytope clockwise.(Optional)
46
+
47
+ max_degree : The maximum degree of any monomial of the input polynomial.(Optional)
48
+
49
+ Examples
50
+ ========
51
+
52
+ >>> from sympy.abc import x, y
53
+ >>> from sympy import Point, Polygon
54
+ >>> from sympy.integrals.intpoly import polytope_integrate
55
+ >>> polygon = Polygon(Point(0, 0), Point(0, 1), Point(1, 1), Point(1, 0))
56
+ >>> polys = [1, x, y, x*y, x**2*y, x*y**2]
57
+ >>> expr = x*y
58
+ >>> polytope_integrate(polygon, expr)
59
+ 1/4
60
+ >>> polytope_integrate(polygon, polys, max_degree=3)
61
+ {1: 1, x: 1/2, y: 1/2, x*y: 1/4, x*y**2: 1/6, x**2*y: 1/6}
62
+ """
63
+ if clockwise:
64
+ if isinstance(poly, Polygon):
65
+ poly = Polygon(*point_sort(poly.vertices), evaluate=False)
66
+ else:
67
+ raise TypeError("clockwise=True works for only 2-Polytope"
68
+ "V-representation input")
69
+
70
+ if isinstance(poly, Polygon):
71
+ # For Vertex Representation(2D case)
72
+ hp_params = hyperplane_parameters(poly)
73
+ facets = poly.sides
74
+ elif len(poly[0]) == 2:
75
+ # For Hyperplane Representation(2D case)
76
+ plen = len(poly)
77
+ if len(poly[0][0]) == 2:
78
+ intersections = [intersection(poly[(i - 1) % plen], poly[i],
79
+ "plane2D")
80
+ for i in range(0, plen)]
81
+ hp_params = poly
82
+ lints = len(intersections)
83
+ facets = [Segment2D(intersections[i],
84
+ intersections[(i + 1) % lints])
85
+ for i in range(lints)]
86
+ else:
87
+ raise NotImplementedError("Integration for H-representation 3D"
88
+ "case not implemented yet.")
89
+ else:
90
+ # For Vertex Representation(3D case)
91
+ vertices = poly[0]
92
+ facets = poly[1:]
93
+ hp_params = hyperplane_parameters(facets, vertices)
94
+
95
+ if max_degree is None:
96
+ if expr is None:
97
+ raise TypeError('Input expression must be a valid SymPy expression')
98
+ return main_integrate3d(expr, facets, vertices, hp_params)
99
+
100
+ if max_degree is not None:
101
+ result = {}
102
+ if expr is not None:
103
+ f_expr = []
104
+ for e in expr:
105
+ _ = decompose(e)
106
+ if len(_) == 1 and not _.popitem()[0]:
107
+ f_expr.append(e)
108
+ elif Poly(e).total_degree() <= max_degree:
109
+ f_expr.append(e)
110
+ expr = f_expr
111
+
112
+ if not isinstance(expr, list) and expr is not None:
113
+ raise TypeError('Input polynomials must be list of expressions')
114
+
115
+ if len(hp_params[0][0]) == 3:
116
+ result_dict = main_integrate3d(0, facets, vertices, hp_params,
117
+ max_degree)
118
+ else:
119
+ result_dict = main_integrate(0, facets, hp_params, max_degree)
120
+
121
+ if expr is None:
122
+ return result_dict
123
+
124
+ for poly in expr:
125
+ poly = _sympify(poly)
126
+ if poly not in result:
127
+ if poly.is_zero:
128
+ result[S.Zero] = S.Zero
129
+ continue
130
+ integral_value = S.Zero
131
+ monoms = decompose(poly, separate=True)
132
+ for monom in monoms:
133
+ monom = nsimplify(monom)
134
+ coeff, m = strip(monom)
135
+ integral_value += result_dict[m] * coeff
136
+ result[poly] = integral_value
137
+ return result
138
+
139
+ if expr is None:
140
+ raise TypeError('Input expression must be a valid SymPy expression')
141
+
142
+ return main_integrate(expr, facets, hp_params)
143
+
144
+
145
+ def strip(monom):
146
+ if monom.is_zero:
147
+ return S.Zero, S.Zero
148
+ elif monom.is_number:
149
+ return monom, S.One
150
+ else:
151
+ coeff = LC(monom)
152
+ return coeff, monom / coeff
153
+
154
+ def _polynomial_integrate(polynomials, facets, hp_params):
155
+ dims = (x, y)
156
+ dim_length = len(dims)
157
+ integral_value = S.Zero
158
+ for deg in polynomials:
159
+ poly_contribute = S.Zero
160
+ facet_count = 0
161
+ for hp in hp_params:
162
+ value_over_boundary = integration_reduction(facets,
163
+ facet_count,
164
+ hp[0], hp[1],
165
+ polynomials[deg],
166
+ dims, deg)
167
+ poly_contribute += value_over_boundary * (hp[1] / norm(hp[0]))
168
+ facet_count += 1
169
+ poly_contribute /= (dim_length + deg)
170
+ integral_value += poly_contribute
171
+
172
+ return integral_value
173
+
174
+
175
+ def main_integrate3d(expr, facets, vertices, hp_params, max_degree=None):
176
+ """Function to translate the problem of integrating uni/bi/tri-variate
177
+ polynomials over a 3-Polytope to integrating over its faces.
178
+ This is done using Generalized Stokes' Theorem and Euler's Theorem.
179
+
180
+ Parameters
181
+ ==========
182
+
183
+ expr :
184
+ The input polynomial.
185
+ facets :
186
+ Faces of the 3-Polytope(expressed as indices of `vertices`).
187
+ vertices :
188
+ Vertices that constitute the Polytope.
189
+ hp_params :
190
+ Hyperplane Parameters of the facets.
191
+ max_degree : optional
192
+ Max degree of constituent monomial in given list of polynomial.
193
+
194
+ Examples
195
+ ========
196
+
197
+ >>> from sympy.integrals.intpoly import main_integrate3d, \
198
+ hyperplane_parameters
199
+ >>> cube = [[(0, 0, 0), (0, 0, 5), (0, 5, 0), (0, 5, 5), (5, 0, 0),\
200
+ (5, 0, 5), (5, 5, 0), (5, 5, 5)],\
201
+ [2, 6, 7, 3], [3, 7, 5, 1], [7, 6, 4, 5], [1, 5, 4, 0],\
202
+ [3, 1, 0, 2], [0, 4, 6, 2]]
203
+ >>> vertices = cube[0]
204
+ >>> faces = cube[1:]
205
+ >>> hp_params = hyperplane_parameters(faces, vertices)
206
+ >>> main_integrate3d(1, faces, vertices, hp_params)
207
+ -125
208
+ """
209
+ result = {}
210
+ dims = (x, y, z)
211
+ dim_length = len(dims)
212
+ if max_degree:
213
+ grad_terms = gradient_terms(max_degree, 3)
214
+ flat_list = [term for z_terms in grad_terms
215
+ for x_term in z_terms
216
+ for term in x_term]
217
+
218
+ for term in flat_list:
219
+ result[term[0]] = 0
220
+
221
+ for facet_count, hp in enumerate(hp_params):
222
+ a, b = hp[0], hp[1]
223
+ x0 = vertices[facets[facet_count][0]]
224
+
225
+ for i, monom in enumerate(flat_list):
226
+ # Every monomial is a tuple :
227
+ # (term, x_degree, y_degree, z_degree, value over boundary)
228
+ expr, x_d, y_d, z_d, z_index, y_index, x_index, _ = monom
229
+ degree = x_d + y_d + z_d
230
+ if b.is_zero:
231
+ value_over_face = S.Zero
232
+ else:
233
+ value_over_face = \
234
+ integration_reduction_dynamic(facets, facet_count, a,
235
+ b, expr, degree, dims,
236
+ x_index, y_index,
237
+ z_index, x0, grad_terms,
238
+ i, vertices, hp)
239
+ monom[7] = value_over_face
240
+ result[expr] += value_over_face * \
241
+ (b / norm(a)) / (dim_length + x_d + y_d + z_d)
242
+ return result
243
+ else:
244
+ integral_value = S.Zero
245
+ polynomials = decompose(expr)
246
+ for deg in polynomials:
247
+ poly_contribute = S.Zero
248
+ facet_count = 0
249
+ for i, facet in enumerate(facets):
250
+ hp = hp_params[i]
251
+ if hp[1].is_zero:
252
+ continue
253
+ pi = polygon_integrate(facet, hp, i, facets, vertices, expr, deg)
254
+ poly_contribute += pi *\
255
+ (hp[1] / norm(tuple(hp[0])))
256
+ facet_count += 1
257
+ poly_contribute /= (dim_length + deg)
258
+ integral_value += poly_contribute
259
+ return integral_value
260
+
261
+
262
+ def main_integrate(expr, facets, hp_params, max_degree=None):
263
+ """Function to translate the problem of integrating univariate/bivariate
264
+ polynomials over a 2-Polytope to integrating over its boundary facets.
265
+ This is done using Generalized Stokes's Theorem and Euler's Theorem.
266
+
267
+ Parameters
268
+ ==========
269
+
270
+ expr :
271
+ The input polynomial.
272
+ facets :
273
+ Facets(Line Segments) of the 2-Polytope.
274
+ hp_params :
275
+ Hyperplane Parameters of the facets.
276
+ max_degree : optional
277
+ The maximum degree of any monomial of the input polynomial.
278
+
279
+ >>> from sympy.abc import x, y
280
+ >>> from sympy.integrals.intpoly import main_integrate,\
281
+ hyperplane_parameters
282
+ >>> from sympy import Point, Polygon
283
+ >>> triangle = Polygon(Point(0, 3), Point(5, 3), Point(1, 1))
284
+ >>> facets = triangle.sides
285
+ >>> hp_params = hyperplane_parameters(triangle)
286
+ >>> main_integrate(x**2 + y**2, facets, hp_params)
287
+ 325/6
288
+ """
289
+ dims = (x, y)
290
+ dim_length = len(dims)
291
+ result = {}
292
+
293
+ if max_degree:
294
+ grad_terms = [[0, 0, 0, 0]] + gradient_terms(max_degree)
295
+
296
+ for facet_count, hp in enumerate(hp_params):
297
+ a, b = hp[0], hp[1]
298
+ x0 = facets[facet_count].points[0]
299
+
300
+ for i, monom in enumerate(grad_terms):
301
+ # Every monomial is a tuple :
302
+ # (term, x_degree, y_degree, value over boundary)
303
+ m, x_d, y_d, _ = monom
304
+ value = result.get(m, None)
305
+ degree = S.Zero
306
+ if b.is_zero:
307
+ value_over_boundary = S.Zero
308
+ else:
309
+ degree = x_d + y_d
310
+ value_over_boundary = \
311
+ integration_reduction_dynamic(facets, facet_count, a,
312
+ b, m, degree, dims, x_d,
313
+ y_d, max_degree, x0,
314
+ grad_terms, i)
315
+ monom[3] = value_over_boundary
316
+ if value is not None:
317
+ result[m] += value_over_boundary * \
318
+ (b / norm(a)) / (dim_length + degree)
319
+ else:
320
+ result[m] = value_over_boundary * \
321
+ (b / norm(a)) / (dim_length + degree)
322
+ return result
323
+ else:
324
+ if not isinstance(expr, list):
325
+ polynomials = decompose(expr)
326
+ return _polynomial_integrate(polynomials, facets, hp_params)
327
+ else:
328
+ return {e: _polynomial_integrate(decompose(e), facets, hp_params) for e in expr}
329
+
330
+
331
+ def polygon_integrate(facet, hp_param, index, facets, vertices, expr, degree):
332
+ """Helper function to integrate the input uni/bi/trivariate polynomial
333
+ over a certain face of the 3-Polytope.
334
+
335
+ Parameters
336
+ ==========
337
+
338
+ facet :
339
+ Particular face of the 3-Polytope over which ``expr`` is integrated.
340
+ index :
341
+ The index of ``facet`` in ``facets``.
342
+ facets :
343
+ Faces of the 3-Polytope(expressed as indices of `vertices`).
344
+ vertices :
345
+ Vertices that constitute the facet.
346
+ expr :
347
+ The input polynomial.
348
+ degree :
349
+ Degree of ``expr``.
350
+
351
+ Examples
352
+ ========
353
+
354
+ >>> from sympy.integrals.intpoly import polygon_integrate
355
+ >>> cube = [[(0, 0, 0), (0, 0, 5), (0, 5, 0), (0, 5, 5), (5, 0, 0),\
356
+ (5, 0, 5), (5, 5, 0), (5, 5, 5)],\
357
+ [2, 6, 7, 3], [3, 7, 5, 1], [7, 6, 4, 5], [1, 5, 4, 0],\
358
+ [3, 1, 0, 2], [0, 4, 6, 2]]
359
+ >>> facet = cube[1]
360
+ >>> facets = cube[1:]
361
+ >>> vertices = cube[0]
362
+ >>> polygon_integrate(facet, [(0, 1, 0), 5], 0, facets, vertices, 1, 0)
363
+ -25
364
+ """
365
+ expr = S(expr)
366
+ if expr.is_zero:
367
+ return S.Zero
368
+ result = S.Zero
369
+ x0 = vertices[facet[0]]
370
+ facet_len = len(facet)
371
+ for i, fac in enumerate(facet):
372
+ side = (vertices[fac], vertices[facet[(i + 1) % facet_len]])
373
+ result += distance_to_side(x0, side, hp_param[0]) *\
374
+ lineseg_integrate(facet, i, side, expr, degree)
375
+ if not expr.is_number:
376
+ expr = diff(expr, x) * x0[0] + diff(expr, y) * x0[1] +\
377
+ diff(expr, z) * x0[2]
378
+ result += polygon_integrate(facet, hp_param, index, facets, vertices,
379
+ expr, degree - 1)
380
+ result /= (degree + 2)
381
+ return result
382
+
383
+
384
+ def distance_to_side(point, line_seg, A):
385
+ """Helper function to compute the signed distance between given 3D point
386
+ and a line segment.
387
+
388
+ Parameters
389
+ ==========
390
+
391
+ point : 3D Point
392
+ line_seg : Line Segment
393
+
394
+ Examples
395
+ ========
396
+
397
+ >>> from sympy.integrals.intpoly import distance_to_side
398
+ >>> point = (0, 0, 0)
399
+ >>> distance_to_side(point, [(0, 0, 1), (0, 1, 0)], (1, 0, 0))
400
+ -sqrt(2)/2
401
+ """
402
+ x1, x2 = line_seg
403
+ rev_normal = [-1 * S(i)/norm(A) for i in A]
404
+ vector = [x2[i] - x1[i] for i in range(0, 3)]
405
+ vector = [vector[i]/norm(vector) for i in range(0, 3)]
406
+
407
+ n_side = cross_product((0, 0, 0), rev_normal, vector)
408
+ vectorx0 = [line_seg[0][i] - point[i] for i in range(0, 3)]
409
+ dot_product = sum(vectorx0[i] * n_side[i] for i in range(0, 3))
410
+
411
+ return dot_product
412
+
413
+
414
+ def lineseg_integrate(polygon, index, line_seg, expr, degree):
415
+ """Helper function to compute the line integral of ``expr`` over ``line_seg``.
416
+
417
+ Parameters
418
+ ===========
419
+
420
+ polygon :
421
+ Face of a 3-Polytope.
422
+ index :
423
+ Index of line_seg in polygon.
424
+ line_seg :
425
+ Line Segment.
426
+
427
+ Examples
428
+ ========
429
+
430
+ >>> from sympy.integrals.intpoly import lineseg_integrate
431
+ >>> polygon = [(0, 5, 0), (5, 5, 0), (5, 5, 5), (0, 5, 5)]
432
+ >>> line_seg = [(0, 5, 0), (5, 5, 0)]
433
+ >>> lineseg_integrate(polygon, 0, line_seg, 1, 0)
434
+ 5
435
+ """
436
+ expr = _sympify(expr)
437
+ if expr.is_zero:
438
+ return S.Zero
439
+ result = S.Zero
440
+ x0 = line_seg[0]
441
+ distance = norm(tuple([line_seg[1][i] - line_seg[0][i] for i in
442
+ range(3)]))
443
+ if isinstance(expr, Expr):
444
+ expr_dict = {x: line_seg[1][0],
445
+ y: line_seg[1][1],
446
+ z: line_seg[1][2]}
447
+ result += distance * expr.subs(expr_dict)
448
+ else:
449
+ result += distance * expr
450
+
451
+ expr = diff(expr, x) * x0[0] + diff(expr, y) * x0[1] +\
452
+ diff(expr, z) * x0[2]
453
+
454
+ result += lineseg_integrate(polygon, index, line_seg, expr, degree - 1)
455
+ result /= (degree + 1)
456
+ return result
457
+
458
+
459
+ def integration_reduction(facets, index, a, b, expr, dims, degree):
460
+ """Helper method for main_integrate. Returns the value of the input
461
+ expression evaluated over the polytope facet referenced by a given index.
462
+
463
+ Parameters
464
+ ===========
465
+
466
+ facets :
467
+ List of facets of the polytope.
468
+ index :
469
+ Index referencing the facet to integrate the expression over.
470
+ a :
471
+ Hyperplane parameter denoting direction.
472
+ b :
473
+ Hyperplane parameter denoting distance.
474
+ expr :
475
+ The expression to integrate over the facet.
476
+ dims :
477
+ List of symbols denoting axes.
478
+ degree :
479
+ Degree of the homogeneous polynomial.
480
+
481
+ Examples
482
+ ========
483
+
484
+ >>> from sympy.abc import x, y
485
+ >>> from sympy.integrals.intpoly import integration_reduction,\
486
+ hyperplane_parameters
487
+ >>> from sympy import Point, Polygon
488
+ >>> triangle = Polygon(Point(0, 3), Point(5, 3), Point(1, 1))
489
+ >>> facets = triangle.sides
490
+ >>> a, b = hyperplane_parameters(triangle)[0]
491
+ >>> integration_reduction(facets, 0, a, b, 1, (x, y), 0)
492
+ 5
493
+ """
494
+ expr = _sympify(expr)
495
+ if expr.is_zero:
496
+ return expr
497
+
498
+ value = S.Zero
499
+ x0 = facets[index].points[0]
500
+ m = len(facets)
501
+ gens = (x, y)
502
+
503
+ inner_product = diff(expr, gens[0]) * x0[0] + diff(expr, gens[1]) * x0[1]
504
+
505
+ if inner_product != 0:
506
+ value += integration_reduction(facets, index, a, b,
507
+ inner_product, dims, degree - 1)
508
+
509
+ value += left_integral2D(m, index, facets, x0, expr, gens)
510
+
511
+ return value/(len(dims) + degree - 1)
512
+
513
+
514
+ def left_integral2D(m, index, facets, x0, expr, gens):
515
+ """Computes the left integral of Eq 10 in Chin et al.
516
+ For the 2D case, the integral is just an evaluation of the polynomial
517
+ at the intersection of two facets which is multiplied by the distance
518
+ between the first point of facet and that intersection.
519
+
520
+ Parameters
521
+ ==========
522
+
523
+ m :
524
+ No. of hyperplanes.
525
+ index :
526
+ Index of facet to find intersections with.
527
+ facets :
528
+ List of facets(Line Segments in 2D case).
529
+ x0 :
530
+ First point on facet referenced by index.
531
+ expr :
532
+ Input polynomial
533
+ gens :
534
+ Generators which generate the polynomial
535
+
536
+ Examples
537
+ ========
538
+
539
+ >>> from sympy.abc import x, y
540
+ >>> from sympy.integrals.intpoly import left_integral2D
541
+ >>> from sympy import Point, Polygon
542
+ >>> triangle = Polygon(Point(0, 3), Point(5, 3), Point(1, 1))
543
+ >>> facets = triangle.sides
544
+ >>> left_integral2D(3, 0, facets, facets[0].points[0], 1, (x, y))
545
+ 5
546
+ """
547
+ value = S.Zero
548
+ for j in range(m):
549
+ intersect = ()
550
+ if j in ((index - 1) % m, (index + 1) % m):
551
+ intersect = intersection(facets[index], facets[j], "segment2D")
552
+ if intersect:
553
+ distance_origin = norm(tuple(map(lambda x, y: x - y,
554
+ intersect, x0)))
555
+ if is_vertex(intersect):
556
+ if isinstance(expr, Expr):
557
+ if len(gens) == 3:
558
+ expr_dict = {gens[0]: intersect[0],
559
+ gens[1]: intersect[1],
560
+ gens[2]: intersect[2]}
561
+ else:
562
+ expr_dict = {gens[0]: intersect[0],
563
+ gens[1]: intersect[1]}
564
+ value += distance_origin * expr.subs(expr_dict)
565
+ else:
566
+ value += distance_origin * expr
567
+ return value
568
+
569
+
570
+ def integration_reduction_dynamic(facets, index, a, b, expr, degree, dims,
571
+ x_index, y_index, max_index, x0,
572
+ monomial_values, monom_index, vertices=None,
573
+ hp_param=None):
574
+ """The same integration_reduction function which uses a dynamic
575
+ programming approach to compute terms by using the values of the integral
576
+ of previously computed terms.
577
+
578
+ Parameters
579
+ ==========
580
+
581
+ facets :
582
+ Facets of the Polytope.
583
+ index :
584
+ Index of facet to find intersections with.(Used in left_integral()).
585
+ a, b :
586
+ Hyperplane parameters.
587
+ expr :
588
+ Input monomial.
589
+ degree :
590
+ Total degree of ``expr``.
591
+ dims :
592
+ Tuple denoting axes variables.
593
+ x_index :
594
+ Exponent of 'x' in ``expr``.
595
+ y_index :
596
+ Exponent of 'y' in ``expr``.
597
+ max_index :
598
+ Maximum exponent of any monomial in ``monomial_values``.
599
+ x0 :
600
+ First point on ``facets[index]``.
601
+ monomial_values :
602
+ List of monomial values constituting the polynomial.
603
+ monom_index :
604
+ Index of monomial whose integration is being found.
605
+ vertices : optional
606
+ Coordinates of vertices constituting the 3-Polytope.
607
+ hp_param : optional
608
+ Hyperplane Parameter of the face of the facets[index].
609
+
610
+ Examples
611
+ ========
612
+
613
+ >>> from sympy.abc import x, y
614
+ >>> from sympy.integrals.intpoly import (integration_reduction_dynamic, \
615
+ hyperplane_parameters)
616
+ >>> from sympy import Point, Polygon
617
+ >>> triangle = Polygon(Point(0, 3), Point(5, 3), Point(1, 1))
618
+ >>> facets = triangle.sides
619
+ >>> a, b = hyperplane_parameters(triangle)[0]
620
+ >>> x0 = facets[0].points[0]
621
+ >>> monomial_values = [[0, 0, 0, 0], [1, 0, 0, 5],\
622
+ [y, 0, 1, 15], [x, 1, 0, None]]
623
+ >>> integration_reduction_dynamic(facets, 0, a, b, x, 1, (x, y), 1, 0, 1,\
624
+ x0, monomial_values, 3)
625
+ 25/2
626
+ """
627
+ value = S.Zero
628
+ m = len(facets)
629
+
630
+ if expr == S.Zero:
631
+ return expr
632
+
633
+ if len(dims) == 2:
634
+ if not expr.is_number:
635
+ _, x_degree, y_degree, _ = monomial_values[monom_index]
636
+ x_index = monom_index - max_index + \
637
+ x_index - 2 if x_degree > 0 else 0
638
+ y_index = monom_index - 1 if y_degree > 0 else 0
639
+ x_value, y_value =\
640
+ monomial_values[x_index][3], monomial_values[y_index][3]
641
+
642
+ value += x_degree * x_value * x0[0] + y_degree * y_value * x0[1]
643
+
644
+ value += left_integral2D(m, index, facets, x0, expr, dims)
645
+ else:
646
+ # For 3D use case the max_index contains the z_degree of the term
647
+ z_index = max_index
648
+ if not expr.is_number:
649
+ x_degree, y_degree, z_degree = y_index,\
650
+ z_index - x_index - y_index, x_index
651
+ x_value = monomial_values[z_index - 1][y_index - 1][x_index][7]\
652
+ if x_degree > 0 else 0
653
+ y_value = monomial_values[z_index - 1][y_index][x_index][7]\
654
+ if y_degree > 0 else 0
655
+ z_value = monomial_values[z_index - 1][y_index][x_index - 1][7]\
656
+ if z_degree > 0 else 0
657
+
658
+ value += x_degree * x_value * x0[0] + y_degree * y_value * x0[1] \
659
+ + z_degree * z_value * x0[2]
660
+
661
+ value += left_integral3D(facets, index, expr,
662
+ vertices, hp_param, degree)
663
+ return value / (len(dims) + degree - 1)
664
+
665
+
666
+ def left_integral3D(facets, index, expr, vertices, hp_param, degree):
667
+ """Computes the left integral of Eq 10 in Chin et al.
668
+
669
+ Explanation
670
+ ===========
671
+
672
+ For the 3D case, this is the sum of the integral values over constituting
673
+ line segments of the face (which is accessed by facets[index]) multiplied
674
+ by the distance between the first point of facet and that line segment.
675
+
676
+ Parameters
677
+ ==========
678
+
679
+ facets :
680
+ List of faces of the 3-Polytope.
681
+ index :
682
+ Index of face over which integral is to be calculated.
683
+ expr :
684
+ Input polynomial.
685
+ vertices :
686
+ List of vertices that constitute the 3-Polytope.
687
+ hp_param :
688
+ The hyperplane parameters of the face.
689
+ degree :
690
+ Degree of the ``expr``.
691
+
692
+ Examples
693
+ ========
694
+
695
+ >>> from sympy.integrals.intpoly import left_integral3D
696
+ >>> cube = [[(0, 0, 0), (0, 0, 5), (0, 5, 0), (0, 5, 5), (5, 0, 0),\
697
+ (5, 0, 5), (5, 5, 0), (5, 5, 5)],\
698
+ [2, 6, 7, 3], [3, 7, 5, 1], [7, 6, 4, 5], [1, 5, 4, 0],\
699
+ [3, 1, 0, 2], [0, 4, 6, 2]]
700
+ >>> facets = cube[1:]
701
+ >>> vertices = cube[0]
702
+ >>> left_integral3D(facets, 3, 1, vertices, ([0, -1, 0], -5), 0)
703
+ -50
704
+ """
705
+ value = S.Zero
706
+ facet = facets[index]
707
+ x0 = vertices[facet[0]]
708
+ facet_len = len(facet)
709
+ for i, fac in enumerate(facet):
710
+ side = (vertices[fac], vertices[facet[(i + 1) % facet_len]])
711
+ value += distance_to_side(x0, side, hp_param[0]) * \
712
+ lineseg_integrate(facet, i, side, expr, degree)
713
+ return value
714
+
715
+
716
+ def gradient_terms(binomial_power=0, no_of_gens=2):
717
+ """Returns a list of all the possible monomials between
718
+ 0 and y**binomial_power for 2D case and z**binomial_power
719
+ for 3D case.
720
+
721
+ Parameters
722
+ ==========
723
+
724
+ binomial_power :
725
+ Power upto which terms are generated.
726
+ no_of_gens :
727
+ Denotes whether terms are being generated for 2D or 3D case.
728
+
729
+ Examples
730
+ ========
731
+
732
+ >>> from sympy.integrals.intpoly import gradient_terms
733
+ >>> gradient_terms(2)
734
+ [[1, 0, 0, 0], [y, 0, 1, 0], [y**2, 0, 2, 0], [x, 1, 0, 0],
735
+ [x*y, 1, 1, 0], [x**2, 2, 0, 0]]
736
+ >>> gradient_terms(2, 3)
737
+ [[[[1, 0, 0, 0, 0, 0, 0, 0]]], [[[y, 0, 1, 0, 1, 0, 0, 0],
738
+ [z, 0, 0, 1, 1, 0, 1, 0]], [[x, 1, 0, 0, 1, 1, 0, 0]]],
739
+ [[[y**2, 0, 2, 0, 2, 0, 0, 0], [y*z, 0, 1, 1, 2, 0, 1, 0],
740
+ [z**2, 0, 0, 2, 2, 0, 2, 0]], [[x*y, 1, 1, 0, 2, 1, 0, 0],
741
+ [x*z, 1, 0, 1, 2, 1, 1, 0]], [[x**2, 2, 0, 0, 2, 2, 0, 0]]]]
742
+ """
743
+ if no_of_gens == 2:
744
+ count = 0
745
+ terms = [None] * int((binomial_power ** 2 + 3 * binomial_power + 2) / 2)
746
+ for x_count in range(0, binomial_power + 1):
747
+ for y_count in range(0, binomial_power - x_count + 1):
748
+ terms[count] = [x**x_count*y**y_count,
749
+ x_count, y_count, 0]
750
+ count += 1
751
+ else:
752
+ terms = [[[[x ** x_count * y ** y_count *
753
+ z ** (z_count - y_count - x_count),
754
+ x_count, y_count, z_count - y_count - x_count,
755
+ z_count, x_count, z_count - y_count - x_count, 0]
756
+ for y_count in range(z_count - x_count, -1, -1)]
757
+ for x_count in range(0, z_count + 1)]
758
+ for z_count in range(0, binomial_power + 1)]
759
+ return terms
760
+
761
+
762
+ def hyperplane_parameters(poly, vertices=None):
763
+ """A helper function to return the hyperplane parameters
764
+ of which the facets of the polytope are a part of.
765
+
766
+ Parameters
767
+ ==========
768
+
769
+ poly :
770
+ The input 2/3-Polytope.
771
+ vertices :
772
+ Vertex indices of 3-Polytope.
773
+
774
+ Examples
775
+ ========
776
+
777
+ >>> from sympy import Point, Polygon
778
+ >>> from sympy.integrals.intpoly import hyperplane_parameters
779
+ >>> hyperplane_parameters(Polygon(Point(0, 3), Point(5, 3), Point(1, 1)))
780
+ [((0, 1), 3), ((1, -2), -1), ((-2, -1), -3)]
781
+ >>> cube = [[(0, 0, 0), (0, 0, 5), (0, 5, 0), (0, 5, 5), (5, 0, 0),\
782
+ (5, 0, 5), (5, 5, 0), (5, 5, 5)],\
783
+ [2, 6, 7, 3], [3, 7, 5, 1], [7, 6, 4, 5], [1, 5, 4, 0],\
784
+ [3, 1, 0, 2], [0, 4, 6, 2]]
785
+ >>> hyperplane_parameters(cube[1:], cube[0])
786
+ [([0, -1, 0], -5), ([0, 0, -1], -5), ([-1, 0, 0], -5),
787
+ ([0, 1, 0], 0), ([1, 0, 0], 0), ([0, 0, 1], 0)]
788
+ """
789
+ if isinstance(poly, Polygon):
790
+ vertices = list(poly.vertices) + [poly.vertices[0]] # Close the polygon
791
+ params = [None] * (len(vertices) - 1)
792
+
793
+ for i in range(len(vertices) - 1):
794
+ v1 = vertices[i]
795
+ v2 = vertices[i + 1]
796
+
797
+ a1 = v1[1] - v2[1]
798
+ a2 = v2[0] - v1[0]
799
+ b = v2[0] * v1[1] - v2[1] * v1[0]
800
+
801
+ factor = gcd_list([a1, a2, b])
802
+
803
+ b = S(b) / factor
804
+ a = (S(a1) / factor, S(a2) / factor)
805
+ params[i] = (a, b)
806
+ else:
807
+ params = [None] * len(poly)
808
+ for i, polygon in enumerate(poly):
809
+ v1, v2, v3 = [vertices[vertex] for vertex in polygon[:3]]
810
+ normal = cross_product(v1, v2, v3)
811
+ b = sum(normal[j] * v1[j] for j in range(0, 3))
812
+ fac = gcd_list(normal)
813
+ if fac.is_zero:
814
+ fac = 1
815
+ normal = [j / fac for j in normal]
816
+ b = b / fac
817
+ params[i] = (normal, b)
818
+ return params
819
+
820
+
821
+ def cross_product(v1, v2, v3):
822
+ """Returns the cross-product of vectors (v2 - v1) and (v3 - v1)
823
+ That is : (v2 - v1) X (v3 - v1)
824
+ """
825
+ v2 = [v2[j] - v1[j] for j in range(0, 3)]
826
+ v3 = [v3[j] - v1[j] for j in range(0, 3)]
827
+ return [v3[2] * v2[1] - v3[1] * v2[2],
828
+ v3[0] * v2[2] - v3[2] * v2[0],
829
+ v3[1] * v2[0] - v3[0] * v2[1]]
830
+
831
+
832
+ def best_origin(a, b, lineseg, expr):
833
+ """Helper method for polytope_integrate. Currently not used in the main
834
+ algorithm.
835
+
836
+ Explanation
837
+ ===========
838
+
839
+ Returns a point on the lineseg whose vector inner product with the
840
+ divergence of `expr` yields an expression with the least maximum
841
+ total power.
842
+
843
+ Parameters
844
+ ==========
845
+
846
+ a :
847
+ Hyperplane parameter denoting direction.
848
+ b :
849
+ Hyperplane parameter denoting distance.
850
+ lineseg :
851
+ Line segment on which to find the origin.
852
+ expr :
853
+ The expression which determines the best point.
854
+
855
+ Algorithm(currently works only for 2D use case)
856
+ ===============================================
857
+
858
+ 1 > Firstly, check for edge cases. Here that would refer to vertical
859
+ or horizontal lines.
860
+
861
+ 2 > If input expression is a polynomial containing more than one generator
862
+ then find out the total power of each of the generators.
863
+
864
+ x**2 + 3 + x*y + x**4*y**5 ---> {x: 7, y: 6}
865
+
866
+ If expression is a constant value then pick the first boundary point
867
+ of the line segment.
868
+
869
+ 3 > First check if a point exists on the line segment where the value of
870
+ the highest power generator becomes 0. If not check if the value of
871
+ the next highest becomes 0. If none becomes 0 within line segment
872
+ constraints then pick the first boundary point of the line segment.
873
+ Actually, any point lying on the segment can be picked as best origin
874
+ in the last case.
875
+
876
+ Examples
877
+ ========
878
+
879
+ >>> from sympy.integrals.intpoly import best_origin
880
+ >>> from sympy.abc import x, y
881
+ >>> from sympy import Point, Segment2D
882
+ >>> l = Segment2D(Point(0, 3), Point(1, 1))
883
+ >>> expr = x**3*y**7
884
+ >>> best_origin((2, 1), 3, l, expr)
885
+ (0, 3.0)
886
+ """
887
+ a1, b1 = lineseg.points[0]
888
+
889
+ def x_axis_cut(ls):
890
+ """Returns the point where the input line segment
891
+ intersects the x-axis.
892
+
893
+ Parameters
894
+ ==========
895
+
896
+ ls :
897
+ Line segment
898
+ """
899
+ p, q = ls.points
900
+ if p.y.is_zero:
901
+ return tuple(p)
902
+ elif q.y.is_zero:
903
+ return tuple(q)
904
+ elif p.y/q.y < S.Zero:
905
+ return p.y * (p.x - q.x)/(q.y - p.y) + p.x, S.Zero
906
+ else:
907
+ return ()
908
+
909
+ def y_axis_cut(ls):
910
+ """Returns the point where the input line segment
911
+ intersects the y-axis.
912
+
913
+ Parameters
914
+ ==========
915
+
916
+ ls :
917
+ Line segment
918
+ """
919
+ p, q = ls.points
920
+ if p.x.is_zero:
921
+ return tuple(p)
922
+ elif q.x.is_zero:
923
+ return tuple(q)
924
+ elif p.x/q.x < S.Zero:
925
+ return S.Zero, p.x * (p.y - q.y)/(q.x - p.x) + p.y
926
+ else:
927
+ return ()
928
+
929
+ gens = (x, y)
930
+ power_gens = {}
931
+
932
+ for i in gens:
933
+ power_gens[i] = S.Zero
934
+
935
+ if len(gens) > 1:
936
+ # Special case for vertical and horizontal lines
937
+ if len(gens) == 2:
938
+ if a[0] == 0:
939
+ if y_axis_cut(lineseg):
940
+ return S.Zero, b/a[1]
941
+ else:
942
+ return a1, b1
943
+ elif a[1] == 0:
944
+ if x_axis_cut(lineseg):
945
+ return b/a[0], S.Zero
946
+ else:
947
+ return a1, b1
948
+
949
+ if isinstance(expr, Expr): # Find the sum total of power of each
950
+ if expr.is_Add: # generator and store in a dictionary.
951
+ for monomial in expr.args:
952
+ if monomial.is_Pow:
953
+ if monomial.args[0] in gens:
954
+ power_gens[monomial.args[0]] += monomial.args[1]
955
+ else:
956
+ for univariate in monomial.args:
957
+ term_type = len(univariate.args)
958
+ if term_type == 0 and univariate in gens:
959
+ power_gens[univariate] += 1
960
+ elif term_type == 2 and univariate.args[0] in gens:
961
+ power_gens[univariate.args[0]] +=\
962
+ univariate.args[1]
963
+ elif expr.is_Mul:
964
+ for term in expr.args:
965
+ term_type = len(term.args)
966
+ if term_type == 0 and term in gens:
967
+ power_gens[term] += 1
968
+ elif term_type == 2 and term.args[0] in gens:
969
+ power_gens[term.args[0]] += term.args[1]
970
+ elif expr.is_Pow:
971
+ power_gens[expr.args[0]] = expr.args[1]
972
+ elif expr.is_Symbol:
973
+ power_gens[expr] += 1
974
+ else: # If `expr` is a constant take first vertex of the line segment.
975
+ return a1, b1
976
+
977
+ # TODO : This part is quite hacky. Should be made more robust with
978
+ # TODO : respect to symbol names and scalable w.r.t higher dimensions.
979
+ power_gens = sorted(power_gens.items(), key=lambda k: str(k[0]))
980
+ if power_gens[0][1] >= power_gens[1][1]:
981
+ if y_axis_cut(lineseg):
982
+ x0 = (S.Zero, b / a[1])
983
+ elif x_axis_cut(lineseg):
984
+ x0 = (b / a[0], S.Zero)
985
+ else:
986
+ x0 = (a1, b1)
987
+ else:
988
+ if x_axis_cut(lineseg):
989
+ x0 = (b/a[0], S.Zero)
990
+ elif y_axis_cut(lineseg):
991
+ x0 = (S.Zero, b/a[1])
992
+ else:
993
+ x0 = (a1, b1)
994
+ else:
995
+ x0 = (b/a[0])
996
+ return x0
997
+
998
+
999
+ def decompose(expr, separate=False):
1000
+ """Decomposes an input polynomial into homogeneous ones of
1001
+ smaller or equal degree.
1002
+
1003
+ Explanation
1004
+ ===========
1005
+
1006
+ Returns a dictionary with keys as the degree of the smaller
1007
+ constituting polynomials. Values are the constituting polynomials.
1008
+
1009
+ Parameters
1010
+ ==========
1011
+
1012
+ expr : Expr
1013
+ Polynomial(SymPy expression).
1014
+ separate : bool
1015
+ If True then simply return a list of the constituent monomials
1016
+ If not then break up the polynomial into constituent homogeneous
1017
+ polynomials.
1018
+
1019
+ Examples
1020
+ ========
1021
+
1022
+ >>> from sympy.abc import x, y
1023
+ >>> from sympy.integrals.intpoly import decompose
1024
+ >>> decompose(x**2 + x*y + x + y + x**3*y**2 + y**5)
1025
+ {1: x + y, 2: x**2 + x*y, 5: x**3*y**2 + y**5}
1026
+ >>> decompose(x**2 + x*y + x + y + x**3*y**2 + y**5, True)
1027
+ {x, x**2, y, y**5, x*y, x**3*y**2}
1028
+ """
1029
+ poly_dict = {}
1030
+
1031
+ if isinstance(expr, Expr) and not expr.is_number:
1032
+ if expr.is_Symbol:
1033
+ poly_dict[1] = expr
1034
+ elif expr.is_Add:
1035
+ symbols = expr.atoms(Symbol)
1036
+ degrees = [(sum(degree_list(monom, *symbols)), monom)
1037
+ for monom in expr.args]
1038
+ if separate:
1039
+ return {monom[1] for monom in degrees}
1040
+ else:
1041
+ for monom in degrees:
1042
+ degree, term = monom
1043
+ if poly_dict.get(degree):
1044
+ poly_dict[degree] += term
1045
+ else:
1046
+ poly_dict[degree] = term
1047
+ elif expr.is_Pow:
1048
+ _, degree = expr.args
1049
+ poly_dict[degree] = expr
1050
+ else: # Now expr can only be of `Mul` type
1051
+ degree = 0
1052
+ for term in expr.args:
1053
+ term_type = len(term.args)
1054
+ if term_type == 0 and term.is_Symbol:
1055
+ degree += 1
1056
+ elif term_type == 2:
1057
+ degree += term.args[1]
1058
+ poly_dict[degree] = expr
1059
+ else:
1060
+ poly_dict[0] = expr
1061
+
1062
+ if separate:
1063
+ return set(poly_dict.values())
1064
+ return poly_dict
1065
+
1066
+
1067
+ def point_sort(poly, normal=None, clockwise=True):
1068
+ """Returns the same polygon with points sorted in clockwise or
1069
+ anti-clockwise order.
1070
+
1071
+ Note that it's necessary for input points to be sorted in some order
1072
+ (clockwise or anti-clockwise) for the integration algorithm to work.
1073
+ As a convention algorithm has been implemented keeping clockwise
1074
+ orientation in mind.
1075
+
1076
+ Parameters
1077
+ ==========
1078
+
1079
+ poly:
1080
+ 2D or 3D Polygon.
1081
+ normal : optional
1082
+ The normal of the plane which the 3-Polytope is a part of.
1083
+ clockwise : bool, optional
1084
+ Returns points sorted in clockwise order if True and
1085
+ anti-clockwise if False.
1086
+
1087
+ Examples
1088
+ ========
1089
+
1090
+ >>> from sympy.integrals.intpoly import point_sort
1091
+ >>> from sympy import Point
1092
+ >>> point_sort([Point(0, 0), Point(1, 0), Point(1, 1)])
1093
+ [Point2D(1, 1), Point2D(1, 0), Point2D(0, 0)]
1094
+ """
1095
+ pts = poly.vertices if isinstance(poly, Polygon) else poly
1096
+ n = len(pts)
1097
+ if n < 2:
1098
+ return list(pts)
1099
+
1100
+ order = S.One if clockwise else S.NegativeOne
1101
+ dim = len(pts[0])
1102
+ if dim == 2:
1103
+ center = Point(sum((vertex.x for vertex in pts)) / n,
1104
+ sum((vertex.y for vertex in pts)) / n)
1105
+ else:
1106
+ center = Point(sum((vertex.x for vertex in pts)) / n,
1107
+ sum((vertex.y for vertex in pts)) / n,
1108
+ sum((vertex.z for vertex in pts)) / n)
1109
+
1110
+ def compare(a, b):
1111
+ if a.x - center.x >= S.Zero and b.x - center.x < S.Zero:
1112
+ return -order
1113
+ elif a.x - center.x < 0 and b.x - center.x >= 0:
1114
+ return order
1115
+ elif a.x - center.x == 0 and b.x - center.x == 0:
1116
+ if a.y - center.y >= 0 or b.y - center.y >= 0:
1117
+ return -order if a.y > b.y else order
1118
+ return -order if b.y > a.y else order
1119
+
1120
+ det = (a.x - center.x) * (b.y - center.y) -\
1121
+ (b.x - center.x) * (a.y - center.y)
1122
+ if det < 0:
1123
+ return -order
1124
+ elif det > 0:
1125
+ return order
1126
+
1127
+ first = (a.x - center.x) * (a.x - center.x) +\
1128
+ (a.y - center.y) * (a.y - center.y)
1129
+ second = (b.x - center.x) * (b.x - center.x) +\
1130
+ (b.y - center.y) * (b.y - center.y)
1131
+ return -order if first > second else order
1132
+
1133
+ def compare3d(a, b):
1134
+ det = cross_product(center, a, b)
1135
+ dot_product = sum(det[i] * normal[i] for i in range(0, 3))
1136
+ if dot_product < 0:
1137
+ return -order
1138
+ elif dot_product > 0:
1139
+ return order
1140
+
1141
+ return sorted(pts, key=cmp_to_key(compare if dim==2 else compare3d))
1142
+
1143
+
1144
+ def norm(point):
1145
+ """Returns the Euclidean norm of a point from origin.
1146
+
1147
+ Parameters
1148
+ ==========
1149
+
1150
+ point:
1151
+ This denotes a point in the dimension_al spac_e.
1152
+
1153
+ Examples
1154
+ ========
1155
+
1156
+ >>> from sympy.integrals.intpoly import norm
1157
+ >>> from sympy import Point
1158
+ >>> norm(Point(2, 7))
1159
+ sqrt(53)
1160
+ """
1161
+ half = S.Half
1162
+ if isinstance(point, (list, tuple)):
1163
+ return sum(coord ** 2 for coord in point) ** half
1164
+ elif isinstance(point, Point):
1165
+ if isinstance(point, Point2D):
1166
+ return (point.x ** 2 + point.y ** 2) ** half
1167
+ else:
1168
+ return (point.x ** 2 + point.y ** 2 + point.z) ** half
1169
+ elif isinstance(point, dict):
1170
+ return sum(i**2 for i in point.values()) ** half
1171
+
1172
+
1173
+ def intersection(geom_1, geom_2, intersection_type):
1174
+ """Returns intersection between geometric objects.
1175
+
1176
+ Explanation
1177
+ ===========
1178
+
1179
+ Note that this function is meant for use in integration_reduction and
1180
+ at that point in the calling function the lines denoted by the segments
1181
+ surely intersect within segment boundaries. Coincident lines are taken
1182
+ to be non-intersecting. Also, the hyperplane intersection for 2D case is
1183
+ also implemented.
1184
+
1185
+ Parameters
1186
+ ==========
1187
+
1188
+ geom_1, geom_2:
1189
+ The input line segments.
1190
+
1191
+ Examples
1192
+ ========
1193
+
1194
+ >>> from sympy.integrals.intpoly import intersection
1195
+ >>> from sympy import Point, Segment2D
1196
+ >>> l1 = Segment2D(Point(1, 1), Point(3, 5))
1197
+ >>> l2 = Segment2D(Point(2, 0), Point(2, 5))
1198
+ >>> intersection(l1, l2, "segment2D")
1199
+ (2, 3)
1200
+ >>> p1 = ((-1, 0), 0)
1201
+ >>> p2 = ((0, 1), 1)
1202
+ >>> intersection(p1, p2, "plane2D")
1203
+ (0, 1)
1204
+ """
1205
+ if intersection_type[:-2] == "segment":
1206
+ if intersection_type == "segment2D":
1207
+ x1, y1 = geom_1.points[0]
1208
+ x2, y2 = geom_1.points[1]
1209
+ x3, y3 = geom_2.points[0]
1210
+ x4, y4 = geom_2.points[1]
1211
+ elif intersection_type == "segment3D":
1212
+ x1, y1, z1 = geom_1.points[0]
1213
+ x2, y2, z2 = geom_1.points[1]
1214
+ x3, y3, z3 = geom_2.points[0]
1215
+ x4, y4, z4 = geom_2.points[1]
1216
+
1217
+ denom = (x1 - x2) * (y3 - y4) - (y1 - y2) * (x3 - x4)
1218
+ if denom:
1219
+ t1 = x1 * y2 - y1 * x2
1220
+ t2 = x3 * y4 - x4 * y3
1221
+ return (S(t1 * (x3 - x4) - t2 * (x1 - x2)) / denom,
1222
+ S(t1 * (y3 - y4) - t2 * (y1 - y2)) / denom)
1223
+ if intersection_type[:-2] == "plane":
1224
+ if intersection_type == "plane2D": # Intersection of hyperplanes
1225
+ a1x, a1y = geom_1[0]
1226
+ a2x, a2y = geom_2[0]
1227
+ b1, b2 = geom_1[1], geom_2[1]
1228
+
1229
+ denom = a1x * a2y - a2x * a1y
1230
+ if denom:
1231
+ return (S(b1 * a2y - b2 * a1y) / denom,
1232
+ S(b2 * a1x - b1 * a2x) / denom)
1233
+
1234
+
1235
+ def is_vertex(ent):
1236
+ """If the input entity is a vertex return True.
1237
+
1238
+ Parameter
1239
+ =========
1240
+
1241
+ ent :
1242
+ Denotes a geometric entity representing a point.
1243
+
1244
+ Examples
1245
+ ========
1246
+
1247
+ >>> from sympy import Point
1248
+ >>> from sympy.integrals.intpoly import is_vertex
1249
+ >>> is_vertex((2, 3))
1250
+ True
1251
+ >>> is_vertex((2, 3, 6))
1252
+ True
1253
+ >>> is_vertex(Point(2, 3))
1254
+ True
1255
+ """
1256
+ if isinstance(ent, tuple):
1257
+ if len(ent) in [2, 3]:
1258
+ return True
1259
+ elif isinstance(ent, Point):
1260
+ return True
1261
+ return False
1262
+
1263
+
1264
+ def plot_polytope(poly):
1265
+ """Plots the 2D polytope using the functions written in plotting
1266
+ module which in turn uses matplotlib backend.
1267
+
1268
+ Parameter
1269
+ =========
1270
+
1271
+ poly:
1272
+ Denotes a 2-Polytope.
1273
+ """
1274
+ from sympy.plotting.plot import Plot, List2DSeries
1275
+
1276
+ xl = [vertex.x for vertex in poly.vertices]
1277
+ yl = [vertex.y for vertex in poly.vertices]
1278
+
1279
+ xl.append(poly.vertices[0].x) # Closing the polygon
1280
+ yl.append(poly.vertices[0].y)
1281
+
1282
+ l2ds = List2DSeries(xl, yl)
1283
+ p = Plot(l2ds, axes='label_axes=True')
1284
+ p.show()
1285
+
1286
+
1287
+ def plot_polynomial(expr):
1288
+ """Plots the polynomial using the functions written in
1289
+ plotting module which in turn uses matplotlib backend.
1290
+
1291
+ Parameter
1292
+ =========
1293
+
1294
+ expr:
1295
+ Denotes a polynomial(SymPy expression).
1296
+ """
1297
+ from sympy.plotting.plot import plot3d, plot
1298
+ gens = expr.free_symbols
1299
+ if len(gens) == 2:
1300
+ plot3d(expr)
1301
+ else:
1302
+ plot(expr)
.venv/lib/python3.12/site-packages/sympy/integrals/laplace.py ADDED
@@ -0,0 +1,2377 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ """Laplace Transforms"""
2
+ import sys
3
+ import sympy
4
+ from sympy.core import S, pi, I
5
+ from sympy.core.add import Add
6
+ from sympy.core.cache import cacheit
7
+ from sympy.core.expr import Expr
8
+ from sympy.core.function import (
9
+ AppliedUndef, Derivative, expand, expand_complex, expand_mul, expand_trig,
10
+ Lambda, WildFunction, diff, Subs)
11
+ from sympy.core.mul import Mul, prod
12
+ from sympy.core.relational import (
13
+ _canonical, Ge, Gt, Lt, Unequality, Eq, Ne, Relational)
14
+ from sympy.core.sorting import ordered
15
+ from sympy.core.symbol import Dummy, symbols, Wild
16
+ from sympy.functions.elementary.complexes import (
17
+ re, im, arg, Abs, polar_lift, periodic_argument)
18
+ from sympy.functions.elementary.exponential import exp, log
19
+ from sympy.functions.elementary.hyperbolic import cosh, coth, sinh, asinh
20
+ from sympy.functions.elementary.miscellaneous import Max, Min, sqrt
21
+ from sympy.functions.elementary.piecewise import (
22
+ Piecewise, piecewise_exclusive)
23
+ from sympy.functions.elementary.trigonometric import cos, sin, atan, sinc
24
+ from sympy.functions.special.bessel import besseli, besselj, besselk, bessely
25
+ from sympy.functions.special.delta_functions import DiracDelta, Heaviside
26
+ from sympy.functions.special.error_functions import erf, erfc, Ei
27
+ from sympy.functions.special.gamma_functions import (
28
+ digamma, gamma, lowergamma, uppergamma)
29
+ from sympy.functions.special.singularity_functions import SingularityFunction
30
+ from sympy.integrals import integrate, Integral
31
+ from sympy.integrals.transforms import (
32
+ _simplify, IntegralTransform, IntegralTransformError)
33
+ from sympy.logic.boolalg import to_cnf, conjuncts, disjuncts, Or, And
34
+ from sympy.matrices.matrixbase import MatrixBase
35
+ from sympy.polys.matrices.linsolve import _lin_eq2dict
36
+ from sympy.polys.polyerrors import PolynomialError
37
+ from sympy.polys.polyroots import roots
38
+ from sympy.polys.polytools import Poly
39
+ from sympy.polys.rationaltools import together
40
+ from sympy.polys.rootoftools import RootSum
41
+ from sympy.utilities.exceptions import (
42
+ sympy_deprecation_warning, SymPyDeprecationWarning, ignore_warnings)
43
+ from sympy.utilities.misc import debugf
44
+
45
+ _LT_level = 0
46
+
47
+
48
+ def DEBUG_WRAP(func):
49
+ def wrap(*args, **kwargs):
50
+ from sympy import SYMPY_DEBUG
51
+ global _LT_level
52
+
53
+ if not SYMPY_DEBUG:
54
+ return func(*args, **kwargs)
55
+
56
+ if _LT_level == 0:
57
+ print('\n' + '-'*78, file=sys.stderr)
58
+ print('-LT- %s%s%s' % (' '*_LT_level, func.__name__, args),
59
+ file=sys.stderr)
60
+ _LT_level += 1
61
+ if (
62
+ func.__name__ == '_laplace_transform_integration' or
63
+ func.__name__ == '_inverse_laplace_transform_integration'):
64
+ sympy.SYMPY_DEBUG = False
65
+ print('**** %sIntegrating ...' % (' '*_LT_level), file=sys.stderr)
66
+ result = func(*args, **kwargs)
67
+ sympy.SYMPY_DEBUG = True
68
+ else:
69
+ result = func(*args, **kwargs)
70
+ _LT_level -= 1
71
+ print('-LT- %s---> %s' % (' '*_LT_level, result), file=sys.stderr)
72
+ if _LT_level == 0:
73
+ print('-'*78 + '\n', file=sys.stderr)
74
+ return result
75
+ return wrap
76
+
77
+
78
+ def _debug(text):
79
+ from sympy import SYMPY_DEBUG
80
+
81
+ if SYMPY_DEBUG:
82
+ print('-LT- %s%s' % (' '*_LT_level, text), file=sys.stderr)
83
+
84
+
85
+ def _simplifyconds(expr, s, a):
86
+ r"""
87
+ Naively simplify some conditions occurring in ``expr``,
88
+ given that `\operatorname{Re}(s) > a`.
89
+
90
+ Examples
91
+ ========
92
+
93
+ >>> from sympy.integrals.laplace import _simplifyconds
94
+ >>> from sympy.abc import x
95
+ >>> from sympy import sympify as S
96
+ >>> _simplifyconds(abs(x**2) < 1, x, 1)
97
+ False
98
+ >>> _simplifyconds(abs(x**2) < 1, x, 2)
99
+ False
100
+ >>> _simplifyconds(abs(x**2) < 1, x, 0)
101
+ Abs(x**2) < 1
102
+ >>> _simplifyconds(abs(1/x**2) < 1, x, 1)
103
+ True
104
+ >>> _simplifyconds(S(1) < abs(x), x, 1)
105
+ True
106
+ >>> _simplifyconds(S(1) < abs(1/x), x, 1)
107
+ False
108
+
109
+ >>> from sympy import Ne
110
+ >>> _simplifyconds(Ne(1, x**3), x, 1)
111
+ True
112
+ >>> _simplifyconds(Ne(1, x**3), x, 2)
113
+ True
114
+ >>> _simplifyconds(Ne(1, x**3), x, 0)
115
+ Ne(1, x**3)
116
+ """
117
+
118
+ def power(ex):
119
+ if ex == s:
120
+ return 1
121
+ if ex.is_Pow and ex.base == s:
122
+ return ex.exp
123
+ return None
124
+
125
+ def bigger(ex1, ex2):
126
+ """ Return True only if |ex1| > |ex2|, False only if |ex1| < |ex2|.
127
+ Else return None. """
128
+ if ex1.has(s) and ex2.has(s):
129
+ return None
130
+ if isinstance(ex1, Abs):
131
+ ex1 = ex1.args[0]
132
+ if isinstance(ex2, Abs):
133
+ ex2 = ex2.args[0]
134
+ if ex1.has(s):
135
+ return bigger(1/ex2, 1/ex1)
136
+ n = power(ex2)
137
+ if n is None:
138
+ return None
139
+ try:
140
+ if n > 0 and (Abs(ex1) <= Abs(a)**n) == S.true:
141
+ return False
142
+ if n < 0 and (Abs(ex1) >= Abs(a)**n) == S.true:
143
+ return True
144
+ except TypeError:
145
+ return None
146
+
147
+ def replie(x, y):
148
+ """ simplify x < y """
149
+ if (not (x.is_positive or isinstance(x, Abs))
150
+ or not (y.is_positive or isinstance(y, Abs))):
151
+ return (x < y)
152
+ r = bigger(x, y)
153
+ if r is not None:
154
+ return not r
155
+ return (x < y)
156
+
157
+ def replue(x, y):
158
+ b = bigger(x, y)
159
+ if b in (True, False):
160
+ return True
161
+ return Unequality(x, y)
162
+
163
+ def repl(ex, *args):
164
+ if ex in (True, False):
165
+ return bool(ex)
166
+ return ex.replace(*args)
167
+
168
+ from sympy.simplify.radsimp import collect_abs
169
+ expr = collect_abs(expr)
170
+ expr = repl(expr, Lt, replie)
171
+ expr = repl(expr, Gt, lambda x, y: replie(y, x))
172
+ expr = repl(expr, Unequality, replue)
173
+ return S(expr)
174
+
175
+
176
+ @DEBUG_WRAP
177
+ def expand_dirac_delta(expr):
178
+ """
179
+ Expand an expression involving DiractDelta to get it as a linear
180
+ combination of DiracDelta functions.
181
+ """
182
+ return _lin_eq2dict(expr, expr.atoms(DiracDelta))
183
+
184
+
185
+ @DEBUG_WRAP
186
+ def _laplace_transform_integration(f, t, s_, *, simplify):
187
+ """ The backend function for doing Laplace transforms by integration.
188
+
189
+ This backend assumes that the frontend has already split sums
190
+ such that `f` is to an addition anymore.
191
+ """
192
+ s = Dummy('s')
193
+
194
+ if f.has(DiracDelta):
195
+ return None
196
+
197
+ F = integrate(f*exp(-s*t), (t, S.Zero, S.Infinity))
198
+
199
+ if not F.has(Integral):
200
+ return _simplify(F.subs(s, s_), simplify), S.NegativeInfinity, S.true
201
+
202
+ if not F.is_Piecewise:
203
+ return None
204
+
205
+ F, cond = F.args[0]
206
+ if F.has(Integral):
207
+ return None
208
+
209
+ def process_conds(conds):
210
+ """ Turn ``conds`` into a strip and auxiliary conditions. """
211
+ from sympy.solvers.inequalities import _solve_inequality
212
+ a = S.NegativeInfinity
213
+ aux = S.true
214
+ conds = conjuncts(to_cnf(conds))
215
+ p, q, w1, w2, w3, w4, w5 = symbols(
216
+ 'p q w1 w2 w3 w4 w5', cls=Wild, exclude=[s])
217
+ patterns = (
218
+ p*Abs(arg((s + w3)*q)) < w2,
219
+ p*Abs(arg((s + w3)*q)) <= w2,
220
+ Abs(periodic_argument((s + w3)**p*q, w1)) < w2,
221
+ Abs(periodic_argument((s + w3)**p*q, w1)) <= w2,
222
+ Abs(periodic_argument((polar_lift(s + w3))**p*q, w1)) < w2,
223
+ Abs(periodic_argument((polar_lift(s + w3))**p*q, w1)) <= w2)
224
+ for c in conds:
225
+ a_ = S.Infinity
226
+ aux_ = []
227
+ for d in disjuncts(c):
228
+ if d.is_Relational and s in d.rhs.free_symbols:
229
+ d = d.reversed
230
+ if d.is_Relational and isinstance(d, (Ge, Gt)):
231
+ d = d.reversedsign
232
+ for pat in patterns:
233
+ m = d.match(pat)
234
+ if m:
235
+ break
236
+ if m and m[q].is_positive and m[w2]/m[p] == pi/2:
237
+ d = -re(s + m[w3]) < 0
238
+ m = d.match(p - cos(w1*Abs(arg(s*w5))*w2)*Abs(s**w3)**w4 < 0)
239
+ if not m:
240
+ m = d.match(
241
+ cos(p - Abs(periodic_argument(s**w1*w5, q))*w2) *
242
+ Abs(s**w3)**w4 < 0)
243
+ if not m:
244
+ m = d.match(
245
+ p - cos(
246
+ Abs(periodic_argument(polar_lift(s)**w1*w5, q))*w2
247
+ )*Abs(s**w3)**w4 < 0)
248
+ if m and all(m[wild].is_positive for wild in [
249
+ w1, w2, w3, w4, w5]):
250
+ d = re(s) > m[p]
251
+ d_ = d.replace(
252
+ re, lambda x: x.expand().as_real_imag()[0]).subs(re(s), t)
253
+ if (
254
+ not d.is_Relational or d.rel_op in ('==', '!=')
255
+ or d_.has(s) or not d_.has(t)):
256
+ aux_ += [d]
257
+ continue
258
+ soln = _solve_inequality(d_, t)
259
+ if not soln.is_Relational or soln.rel_op in ('==', '!='):
260
+ aux_ += [d]
261
+ continue
262
+ if soln.lts == t:
263
+ return None
264
+ else:
265
+ a_ = Min(soln.lts, a_)
266
+ if a_ is not S.Infinity:
267
+ a = Max(a_, a)
268
+ else:
269
+ aux = And(aux, Or(*aux_))
270
+ return a, aux.canonical if aux.is_Relational else aux
271
+
272
+ conds = [process_conds(c) for c in disjuncts(cond)]
273
+ conds2 = [x for x in conds if x[1] !=
274
+ S.false and x[0] is not S.NegativeInfinity]
275
+ if not conds2:
276
+ conds2 = [x for x in conds if x[1] != S.false]
277
+ conds = list(ordered(conds2))
278
+
279
+ def cnt(expr):
280
+ if expr in (True, False):
281
+ return 0
282
+ return expr.count_ops()
283
+ conds.sort(key=lambda x: (-x[0], cnt(x[1])))
284
+
285
+ if not conds:
286
+ return None
287
+ a, aux = conds[0] # XXX is [0] always the right one?
288
+
289
+ def sbs(expr):
290
+ return expr.subs(s, s_)
291
+ if simplify:
292
+ F = _simplifyconds(F, s, a)
293
+ aux = _simplifyconds(aux, s, a)
294
+ return _simplify(F.subs(s, s_), simplify), sbs(a), _canonical(sbs(aux))
295
+
296
+
297
+ @DEBUG_WRAP
298
+ def _laplace_deep_collect(f, t):
299
+ """
300
+ This is an internal helper function that traverses through the expression
301
+ tree of `f(t)` and collects arguments. The purpose of it is that
302
+ anything like `f(w*t-1*t-c)` will be written as `f((w-1)*t-c)` such that
303
+ it can match `f(a*t+b)`.
304
+ """
305
+ if not isinstance(f, Expr):
306
+ return f
307
+ if (p := f.as_poly(t)) is not None:
308
+ return p.as_expr()
309
+ func = f.func
310
+ args = [_laplace_deep_collect(arg, t) for arg in f.args]
311
+ return func(*args)
312
+
313
+
314
+ @cacheit
315
+ def _laplace_build_rules():
316
+ """
317
+ This is an internal helper function that returns the table of Laplace
318
+ transform rules in terms of the time variable `t` and the frequency
319
+ variable `s`. It is used by ``_laplace_apply_rules``. Each entry is a
320
+ tuple containing:
321
+
322
+ (time domain pattern,
323
+ frequency-domain replacement,
324
+ condition for the rule to be applied,
325
+ convergence plane,
326
+ preparation function)
327
+
328
+ The preparation function is a function with one argument that is applied
329
+ to the expression before matching. For most rules it should be
330
+ ``_laplace_deep_collect``.
331
+ """
332
+ t = Dummy('t')
333
+ s = Dummy('s')
334
+ a = Wild('a', exclude=[t])
335
+ b = Wild('b', exclude=[t])
336
+ n = Wild('n', exclude=[t])
337
+ tau = Wild('tau', exclude=[t])
338
+ omega = Wild('omega', exclude=[t])
339
+ def dco(f): return _laplace_deep_collect(f, t)
340
+ _debug('_laplace_build_rules is building rules')
341
+
342
+ laplace_transform_rules = [
343
+ (a, a/s,
344
+ S.true, S.Zero, dco), # 4.2.1
345
+ (DiracDelta(a*t-b), exp(-s*b/a)/Abs(a),
346
+ Or(And(a > 0, b >= 0), And(a < 0, b <= 0)),
347
+ S.NegativeInfinity, dco), # Not in Bateman54
348
+ (DiracDelta(a*t-b), S(0),
349
+ Or(And(a < 0, b >= 0), And(a > 0, b <= 0)),
350
+ S.NegativeInfinity, dco), # Not in Bateman54
351
+ (Heaviside(a*t-b), exp(-s*b/a)/s,
352
+ And(a > 0, b > 0), S.Zero, dco), # 4.4.1
353
+ (Heaviside(a*t-b), (1-exp(-s*b/a))/s,
354
+ And(a < 0, b < 0), S.Zero, dco), # 4.4.1
355
+ (Heaviside(a*t-b), 1/s,
356
+ And(a > 0, b <= 0), S.Zero, dco), # 4.4.1
357
+ (Heaviside(a*t-b), 0,
358
+ And(a < 0, b > 0), S.Zero, dco), # 4.4.1
359
+ (t, 1/s**2,
360
+ S.true, S.Zero, dco), # 4.2.3
361
+ (1/(a*t+b), -exp(-b/a*s)*Ei(-b/a*s)/a,
362
+ Abs(arg(b/a)) < pi, S.Zero, dco), # 4.2.6
363
+ (1/sqrt(a*t+b), sqrt(a*pi/s)*exp(b/a*s)*erfc(sqrt(b/a*s))/a,
364
+ Abs(arg(b/a)) < pi, S.Zero, dco), # 4.2.18
365
+ ((a*t+b)**(-S(3)/2),
366
+ 2*b**(-S(1)/2)-2*(pi*s/a)**(S(1)/2)*exp(b/a*s) * erfc(sqrt(b/a*s))/a,
367
+ Abs(arg(b/a)) < pi, S.Zero, dco), # 4.2.20
368
+ (sqrt(t)/(t+b), sqrt(pi/s)-pi*sqrt(b)*exp(b*s)*erfc(sqrt(b*s)),
369
+ Abs(arg(b)) < pi, S.Zero, dco), # 4.2.22
370
+ (1/(a*sqrt(t) + t**(3/2)), pi*a**(S(1)/2)*exp(a*s)*erfc(sqrt(a*s)),
371
+ S.true, S.Zero, dco), # Not in Bateman54
372
+ (t**n, gamma(n+1)/s**(n+1),
373
+ n > -1, S.Zero, dco), # 4.3.1
374
+ ((a*t+b)**n, uppergamma(n+1, b/a*s)*exp(-b/a*s)/s**(n+1)/a,
375
+ And(n > -1, Abs(arg(b/a)) < pi), S.Zero, dco), # 4.3.4
376
+ (t**n/(t+a), a**n*gamma(n+1)*uppergamma(-n, a*s),
377
+ And(n > -1, Abs(arg(a)) < pi), S.Zero, dco), # 4.3.7
378
+ (exp(a*t-tau), exp(-tau)/(s-a),
379
+ S.true, re(a), dco), # 4.5.1
380
+ (t*exp(a*t-tau), exp(-tau)/(s-a)**2,
381
+ S.true, re(a), dco), # 4.5.2
382
+ (t**n*exp(a*t), gamma(n+1)/(s-a)**(n+1),
383
+ re(n) > -1, re(a), dco), # 4.5.3
384
+ (exp(-a*t**2), sqrt(pi/4/a)*exp(s**2/4/a)*erfc(s/sqrt(4*a)),
385
+ re(a) > 0, S.Zero, dco), # 4.5.21
386
+ (t*exp(-a*t**2),
387
+ 1/(2*a)-2/sqrt(pi)/(4*a)**(S(3)/2)*s*erfc(s/sqrt(4*a)),
388
+ re(a) > 0, S.Zero, dco), # 4.5.22
389
+ (exp(-a/t), 2*sqrt(a/s)*besselk(1, 2*sqrt(a*s)),
390
+ re(a) >= 0, S.Zero, dco), # 4.5.25
391
+ (sqrt(t)*exp(-a/t),
392
+ S(1)/2*sqrt(pi/s**3)*(1+2*sqrt(a*s))*exp(-2*sqrt(a*s)),
393
+ re(a) >= 0, S.Zero, dco), # 4.5.26
394
+ (exp(-a/t)/sqrt(t), sqrt(pi/s)*exp(-2*sqrt(a*s)),
395
+ re(a) >= 0, S.Zero, dco), # 4.5.27
396
+ (exp(-a/t)/(t*sqrt(t)), sqrt(pi/a)*exp(-2*sqrt(a*s)),
397
+ re(a) > 0, S.Zero, dco), # 4.5.28
398
+ (t**n*exp(-a/t), 2*(a/s)**((n+1)/2)*besselk(n+1, 2*sqrt(a*s)),
399
+ re(a) > 0, S.Zero, dco), # 4.5.29
400
+ # TODO: rules with sqrt(a*t) and sqrt(a/t) have stopped working after
401
+ # changes to as_base_exp
402
+ # (exp(-2*sqrt(a*t)),
403
+ # s**(-1)-sqrt(pi*a)*s**(-S(3)/2)*exp(a/s) * erfc(sqrt(a/s)),
404
+ # Abs(arg(a)) < pi, S.Zero, dco), # 4.5.31
405
+ # (exp(-2*sqrt(a*t))/sqrt(t), (pi/s)**(S(1)/2)*exp(a/s)*erfc(sqrt(a/s)),
406
+ # Abs(arg(a)) < pi, S.Zero, dco), # 4.5.33
407
+ (exp(-a*exp(-t)), a**(-s)*lowergamma(s, a),
408
+ S.true, S.Zero, dco), # 4.5.36
409
+ (exp(-a*exp(t)), a**s*uppergamma(-s, a),
410
+ re(a) > 0, S.Zero, dco), # 4.5.37
411
+ (log(a*t), -log(exp(S.EulerGamma)*s/a)/s,
412
+ a > 0, S.Zero, dco), # 4.6.1
413
+ (log(1+a*t), -exp(s/a)/s*Ei(-s/a),
414
+ Abs(arg(a)) < pi, S.Zero, dco), # 4.6.4
415
+ (log(a*t+b), (log(b)-exp(s/b/a)/s*a*Ei(-s/b))/s*a,
416
+ And(a > 0, Abs(arg(b)) < pi), S.Zero, dco), # 4.6.5
417
+ (log(t)/sqrt(t), -sqrt(pi/s)*log(4*s*exp(S.EulerGamma)),
418
+ S.true, S.Zero, dco), # 4.6.9
419
+ (t**n*log(t), gamma(n+1)*s**(-n-1)*(digamma(n+1)-log(s)),
420
+ re(n) > -1, S.Zero, dco), # 4.6.11
421
+ (log(a*t)**2, (log(exp(S.EulerGamma)*s/a)**2+pi**2/6)/s,
422
+ a > 0, S.Zero, dco), # 4.6.13
423
+ (sin(omega*t), omega/(s**2+omega**2),
424
+ S.true, Abs(im(omega)), dco), # 4,7,1
425
+ (Abs(sin(omega*t)), omega/(s**2+omega**2)*coth(pi*s/2/omega),
426
+ omega > 0, S.Zero, dco), # 4.7.2
427
+ (sin(omega*t)/t, atan(omega/s),
428
+ S.true, Abs(im(omega)), dco), # 4.7.16
429
+ (sin(omega*t)**2/t, log(1+4*omega**2/s**2)/4,
430
+ S.true, 2*Abs(im(omega)), dco), # 4.7.17
431
+ (sin(omega*t)**2/t**2,
432
+ omega*atan(2*omega/s)-s*log(1+4*omega**2/s**2)/4,
433
+ S.true, 2*Abs(im(omega)), dco), # 4.7.20
434
+ # (sin(2*sqrt(a*t)), sqrt(pi*a)/s/sqrt(s)*exp(-a/s),
435
+ # S.true, S.Zero, dco), # 4.7.32
436
+ # (sin(2*sqrt(a*t))/t, pi*erf(sqrt(a/s)),
437
+ # S.true, S.Zero, dco), # 4.7.34
438
+ (cos(omega*t), s/(s**2+omega**2),
439
+ S.true, Abs(im(omega)), dco), # 4.7.43
440
+ (cos(omega*t)**2, (s**2+2*omega**2)/(s**2+4*omega**2)/s,
441
+ S.true, 2*Abs(im(omega)), dco), # 4.7.45
442
+ # (sqrt(t)*cos(2*sqrt(a*t)), sqrt(pi)/2*s**(-S(5)/2)*(s-2*a)*exp(-a/s),
443
+ # S.true, S.Zero, dco), # 4.7.66
444
+ # (cos(2*sqrt(a*t))/sqrt(t), sqrt(pi/s)*exp(-a/s),
445
+ # S.true, S.Zero, dco), # 4.7.67
446
+ (sin(a*t)*sin(b*t), 2*a*b*s/(s**2+(a+b)**2)/(s**2+(a-b)**2),
447
+ S.true, Abs(im(a))+Abs(im(b)), dco), # 4.7.78
448
+ (cos(a*t)*sin(b*t), b*(s**2-a**2+b**2)/(s**2+(a+b)**2)/(s**2+(a-b)**2),
449
+ S.true, Abs(im(a))+Abs(im(b)), dco), # 4.7.79
450
+ (cos(a*t)*cos(b*t), s*(s**2+a**2+b**2)/(s**2+(a+b)**2)/(s**2+(a-b)**2),
451
+ S.true, Abs(im(a))+Abs(im(b)), dco), # 4.7.80
452
+ (sinh(a*t), a/(s**2-a**2),
453
+ S.true, Abs(re(a)), dco), # 4.9.1
454
+ (cosh(a*t), s/(s**2-a**2),
455
+ S.true, Abs(re(a)), dco), # 4.9.2
456
+ (sinh(a*t)**2, 2*a**2/(s**3-4*a**2*s),
457
+ S.true, 2*Abs(re(a)), dco), # 4.9.3
458
+ (cosh(a*t)**2, (s**2-2*a**2)/(s**3-4*a**2*s),
459
+ S.true, 2*Abs(re(a)), dco), # 4.9.4
460
+ (sinh(a*t)/t, log((s+a)/(s-a))/2,
461
+ S.true, Abs(re(a)), dco), # 4.9.12
462
+ (t**n*sinh(a*t), gamma(n+1)/2*((s-a)**(-n-1)-(s+a)**(-n-1)),
463
+ n > -2, Abs(a), dco), # 4.9.18
464
+ (t**n*cosh(a*t), gamma(n+1)/2*((s-a)**(-n-1)+(s+a)**(-n-1)),
465
+ n > -1, Abs(a), dco), # 4.9.19
466
+ # TODO
467
+ # (sinh(2*sqrt(a*t)), sqrt(pi*a)/s/sqrt(s)*exp(a/s),
468
+ # S.true, S.Zero, dco), # 4.9.34
469
+ # (cosh(2*sqrt(a*t)), 1/s+sqrt(pi*a)/s/sqrt(s)*exp(a/s)*erf(sqrt(a/s)),
470
+ # S.true, S.Zero, dco), # 4.9.35
471
+ # (
472
+ # sqrt(t)*sinh(2*sqrt(a*t)),
473
+ # pi**(S(1)/2)*s**(-S(5)/2)*(s/2+a) *
474
+ # exp(a/s)*erf(sqrt(a/s))-a**(S(1)/2)*s**(-2),
475
+ # S.true, S.Zero, dco), # 4.9.36
476
+ # (sqrt(t)*cosh(2*sqrt(a*t)), pi**(S(1)/2)*s**(-S(5)/2)*(s/2+a)*exp(a/s),
477
+ # S.true, S.Zero, dco), # 4.9.37
478
+ # (sinh(2*sqrt(a*t))/sqrt(t),
479
+ # pi**(S(1)/2)*s**(-S(1)/2)*exp(a/s) * erf(sqrt(a/s)),
480
+ # S.true, S.Zero, dco), # 4.9.38
481
+ # (cosh(2*sqrt(a*t))/sqrt(t), pi**(S(1)/2)*s**(-S(1)/2)*exp(a/s),
482
+ # S.true, S.Zero, dco), # 4.9.39
483
+ # (sinh(sqrt(a*t))**2/sqrt(t), pi**(S(1)/2)/2*s**(-S(1)/2)*(exp(a/s)-1),
484
+ # S.true, S.Zero, dco), # 4.9.40
485
+ # (cosh(sqrt(a*t))**2/sqrt(t), pi**(S(1)/2)/2*s**(-S(1)/2)*(exp(a/s)+1),
486
+ # S.true, S.Zero, dco), # 4.9.41
487
+ (erf(a*t), exp(s**2/(2*a)**2)*erfc(s/(2*a))/s,
488
+ 4*Abs(arg(a)) < pi, S.Zero, dco), # 4.12.2
489
+ # (erf(sqrt(a*t)), sqrt(a)/sqrt(s+a)/s,
490
+ # S.true, Max(S.Zero, -re(a)), dco), # 4.12.4
491
+ # (exp(a*t)*erf(sqrt(a*t)), sqrt(a)/sqrt(s)/(s-a),
492
+ # S.true, Max(S.Zero, re(a)), dco), # 4.12.5
493
+ # (erf(sqrt(a/t)/2), (1-exp(-sqrt(a*s)))/s,
494
+ # re(a) > 0, S.Zero, dco), # 4.12.6
495
+ # (erfc(sqrt(a*t)), (sqrt(s+a)-sqrt(a))/sqrt(s+a)/s,
496
+ # S.true, -re(a), dco), # 4.12.9
497
+ # (exp(a*t)*erfc(sqrt(a*t)), 1/(s+sqrt(a*s)),
498
+ # S.true, S.Zero, dco), # 4.12.10
499
+ # (erfc(sqrt(a/t)/2), exp(-sqrt(a*s))/s,
500
+ # re(a) > 0, S.Zero, dco), # 4.2.11
501
+ (besselj(n, a*t), a**n/(sqrt(s**2+a**2)*(s+sqrt(s**2+a**2))**n),
502
+ re(n) > -1, Abs(im(a)), dco), # 4.14.1
503
+ (t**b*besselj(n, a*t),
504
+ 2**n/sqrt(pi)*gamma(n+S.Half)*a**n*(s**2+a**2)**(-n-S.Half),
505
+ And(re(n) > -S.Half, Eq(b, n)), Abs(im(a)), dco), # 4.14.7
506
+ (t**b*besselj(n, a*t),
507
+ 2**(n+1)/sqrt(pi)*gamma(n+S(3)/2)*a**n*s*(s**2+a**2)**(-n-S(3)/2),
508
+ And(re(n) > -1, Eq(b, n+1)), Abs(im(a)), dco), # 4.14.8
509
+ # (besselj(0, 2*sqrt(a*t)), exp(-a/s)/s,
510
+ # S.true, S.Zero, dco), # 4.14.25
511
+ # (t**(b)*besselj(n, 2*sqrt(a*t)), a**(n/2)*s**(-n-1)*exp(-a/s),
512
+ # And(re(n) > -1, Eq(b, n*S.Half)), S.Zero, dco), # 4.14.30
513
+ (besselj(0, a*sqrt(t**2+b*t)),
514
+ exp(b*s-b*sqrt(s**2+a**2))/sqrt(s**2+a**2),
515
+ Abs(arg(b)) < pi, Abs(im(a)), dco), # 4.15.19
516
+ (besseli(n, a*t), a**n/(sqrt(s**2-a**2)*(s+sqrt(s**2-a**2))**n),
517
+ re(n) > -1, Abs(re(a)), dco), # 4.16.1
518
+ (t**b*besseli(n, a*t),
519
+ 2**n/sqrt(pi)*gamma(n+S.Half)*a**n*(s**2-a**2)**(-n-S.Half),
520
+ And(re(n) > -S.Half, Eq(b, n)), Abs(re(a)), dco), # 4.16.6
521
+ (t**b*besseli(n, a*t),
522
+ 2**(n+1)/sqrt(pi)*gamma(n+S(3)/2)*a**n*s*(s**2-a**2)**(-n-S(3)/2),
523
+ And(re(n) > -1, Eq(b, n+1)), Abs(re(a)), dco), # 4.16.7
524
+ # (t**(b)*besseli(n, 2*sqrt(a*t)), a**(n/2)*s**(-n-1)*exp(a/s),
525
+ # And(re(n) > -1, Eq(b, n*S.Half)), S.Zero, dco), # 4.16.18
526
+ (bessely(0, a*t), -2/pi*asinh(s/a)/sqrt(s**2+a**2),
527
+ S.true, Abs(im(a)), dco), # 4.15.44
528
+ (besselk(0, a*t), log((s + sqrt(s**2-a**2))/a)/(sqrt(s**2-a**2)),
529
+ S.true, -re(a), dco) # 4.16.23
530
+ ]
531
+ return laplace_transform_rules, t, s
532
+
533
+
534
+ @DEBUG_WRAP
535
+ def _laplace_rule_timescale(f, t, s):
536
+ """
537
+ This function applies the time-scaling rule of the Laplace transform in
538
+ a straight-forward way. For example, if it gets ``(f(a*t), t, s)``, it will
539
+ compute ``LaplaceTransform(f(t)/a, t, s/a)`` if ``a>0``.
540
+ """
541
+
542
+ a = Wild('a', exclude=[t])
543
+ g = WildFunction('g', nargs=1)
544
+ ma1 = f.match(g)
545
+ if ma1:
546
+ arg = ma1[g].args[0].collect(t)
547
+ ma2 = arg.match(a*t)
548
+ if ma2 and ma2[a].is_positive and ma2[a] != 1:
549
+ _debug(' rule: time scaling (4.1.4)')
550
+ r, pr, cr = _laplace_transform(
551
+ 1/ma2[a]*ma1[g].func(t), t, s/ma2[a], simplify=False)
552
+ return (r, pr, cr)
553
+ return None
554
+
555
+
556
+ @DEBUG_WRAP
557
+ def _laplace_rule_heaviside(f, t, s):
558
+ """
559
+ This function deals with time-shifted Heaviside step functions. If the time
560
+ shift is positive, it applies the time-shift rule of the Laplace transform.
561
+ For example, if it gets ``(Heaviside(t-a)*f(t), t, s)``, it will compute
562
+ ``exp(-a*s)*LaplaceTransform(f(t+a), t, s)``.
563
+
564
+ If the time shift is negative, the Heaviside function is simply removed
565
+ as it means nothing to the Laplace transform.
566
+
567
+ The function does not remove a factor ``Heaviside(t)``; this is done by
568
+ the simple rules.
569
+ """
570
+
571
+ a = Wild('a', exclude=[t])
572
+ y = Wild('y')
573
+ g = Wild('g')
574
+ if ma1 := f.match(Heaviside(y) * g):
575
+ if ma2 := ma1[y].match(t - a):
576
+ if ma2[a].is_positive:
577
+ _debug(' rule: time shift (4.1.4)')
578
+ r, pr, cr = _laplace_transform(
579
+ ma1[g].subs(t, t + ma2[a]), t, s, simplify=False)
580
+ return (exp(-ma2[a] * s) * r, pr, cr)
581
+ if ma2[a].is_negative:
582
+ _debug(
583
+ ' rule: Heaviside factor; negative time shift (4.1.4)')
584
+ r, pr, cr = _laplace_transform(ma1[g], t, s, simplify=False)
585
+ return (r, pr, cr)
586
+ if ma2 := ma1[y].match(a - t):
587
+ if ma2[a].is_positive:
588
+ _debug(' rule: Heaviside window open')
589
+ r, pr, cr = _laplace_transform(
590
+ (1 - Heaviside(t - ma2[a])) * ma1[g], t, s, simplify=False)
591
+ return (r, pr, cr)
592
+ if ma2[a].is_negative:
593
+ _debug(' rule: Heaviside window closed')
594
+ return (0, 0, S.true)
595
+ return None
596
+
597
+
598
+ @DEBUG_WRAP
599
+ def _laplace_rule_exp(f, t, s):
600
+ """
601
+ If this function finds a factor ``exp(a*t)``, it applies the
602
+ frequency-shift rule of the Laplace transform and adjusts the convergence
603
+ plane accordingly. For example, if it gets ``(exp(-a*t)*f(t), t, s)``, it
604
+ will compute ``LaplaceTransform(f(t), t, s+a)``.
605
+ """
606
+
607
+ a = Wild('a', exclude=[t])
608
+ y = Wild('y')
609
+ z = Wild('z')
610
+ ma1 = f.match(exp(y)*z)
611
+ if ma1:
612
+ ma2 = ma1[y].collect(t).match(a*t)
613
+ if ma2:
614
+ _debug(' rule: multiply with exp (4.1.5)')
615
+ r, pr, cr = _laplace_transform(ma1[z], t, s-ma2[a],
616
+ simplify=False)
617
+ return (r, pr+re(ma2[a]), cr)
618
+ return None
619
+
620
+
621
+ @DEBUG_WRAP
622
+ def _laplace_rule_delta(f, t, s):
623
+ """
624
+ If this function finds a factor ``DiracDelta(b*t-a)``, it applies the
625
+ masking property of the delta distribution. For example, if it gets
626
+ ``(DiracDelta(t-a)*f(t), t, s)``, it will return
627
+ ``(f(a)*exp(-a*s), -a, True)``.
628
+ """
629
+ # This rule is not in Bateman54
630
+
631
+ a = Wild('a', exclude=[t])
632
+ b = Wild('b', exclude=[t])
633
+
634
+ y = Wild('y')
635
+ z = Wild('z')
636
+ ma1 = f.match(DiracDelta(y)*z)
637
+ if ma1 and not ma1[z].has(DiracDelta):
638
+ ma2 = ma1[y].collect(t).match(b*t-a)
639
+ if ma2:
640
+ _debug(' rule: multiply with DiracDelta')
641
+ loc = ma2[a]/ma2[b]
642
+ if re(loc) >= 0 and im(loc) == 0:
643
+ fn = exp(-ma2[a]/ma2[b]*s)*ma1[z]
644
+ if fn.has(sin, cos):
645
+ # Then it may be possible that a sinc() is present in the
646
+ # term; let's try this:
647
+ fn = fn.rewrite(sinc).ratsimp()
648
+ n, d = [x.subs(t, ma2[a]/ma2[b]) for x in fn.as_numer_denom()]
649
+ if d != 0:
650
+ return (n/d/ma2[b], S.NegativeInfinity, S.true)
651
+ else:
652
+ return None
653
+ else:
654
+ return (0, S.NegativeInfinity, S.true)
655
+ if ma1[y].is_polynomial(t):
656
+ ro = roots(ma1[y], t)
657
+ if ro != {} and set(ro.values()) == {1}:
658
+ slope = diff(ma1[y], t)
659
+ r = Add(
660
+ *[exp(-x*s)*ma1[z].subs(t, s)/slope.subs(t, x)
661
+ for x in list(ro.keys()) if im(x) == 0 and re(x) >= 0])
662
+ return (r, S.NegativeInfinity, S.true)
663
+ return None
664
+
665
+
666
+ @DEBUG_WRAP
667
+ def _laplace_trig_split(fn):
668
+ """
669
+ Helper function for `_laplace_rule_trig`. This function returns two terms
670
+ `f` and `g`. `f` contains all product terms with sin, cos, sinh, cosh in
671
+ them; `g` contains everything else.
672
+ """
673
+ trigs = [S.One]
674
+ other = [S.One]
675
+ for term in Mul.make_args(fn):
676
+ if term.has(sin, cos, sinh, cosh, exp):
677
+ trigs.append(term)
678
+ else:
679
+ other.append(term)
680
+ f = Mul(*trigs)
681
+ g = Mul(*other)
682
+ return f, g
683
+
684
+
685
+ @DEBUG_WRAP
686
+ def _laplace_trig_expsum(f, t):
687
+ """
688
+ Helper function for `_laplace_rule_trig`. This function expects the `f`
689
+ from `_laplace_trig_split`. It returns two lists `xm` and `xn`. `xm` is
690
+ a list of dictionaries with keys `k` and `a` representing a function
691
+ `k*exp(a*t)`. `xn` is a list of all terms that cannot be brought into
692
+ that form, which may happen, e.g., when a trigonometric function has
693
+ another function in its argument.
694
+ """
695
+ c1 = Wild('c1', exclude=[t])
696
+ c0 = Wild('c0', exclude=[t])
697
+ p = Wild('p', exclude=[t])
698
+ xm = []
699
+ xn = []
700
+
701
+ x1 = f.rewrite(exp).expand()
702
+
703
+ for term in Add.make_args(x1):
704
+ if not term.has(t):
705
+ xm.append({'k': term, 'a': 0, re: 0, im: 0})
706
+ continue
707
+ term = _laplace_deep_collect(term.powsimp(combine='exp'), t)
708
+
709
+ if (r := term.match(p*exp(c1*t+c0))) is not None:
710
+ xm.append({
711
+ 'k': r[p]*exp(r[c0]), 'a': r[c1],
712
+ re: re(r[c1]), im: im(r[c1])})
713
+ else:
714
+ xn.append(term)
715
+ return xm, xn
716
+
717
+
718
+ @DEBUG_WRAP
719
+ def _laplace_trig_ltex(xm, t, s):
720
+ """
721
+ Helper function for `_laplace_rule_trig`. This function takes the list of
722
+ exponentials `xm` from `_laplace_trig_expsum` and simplifies complex
723
+ conjugate and real symmetric poles. It returns the result as a sum and
724
+ the convergence plane.
725
+ """
726
+ results = []
727
+ planes = []
728
+
729
+ def _simpc(coeffs):
730
+ nc = coeffs.copy()
731
+ for k in range(len(nc)):
732
+ ri = nc[k].as_real_imag()
733
+ if ri[0].has(im):
734
+ nc[k] = nc[k].rewrite(cos)
735
+ else:
736
+ nc[k] = (ri[0] + I*ri[1]).rewrite(cos)
737
+ return nc
738
+
739
+ def _quadpole(t1, k1, k2, k3, s):
740
+ a, k0, a_r, a_i = t1['a'], t1['k'], t1[re], t1[im]
741
+ nc = [
742
+ k0 + k1 + k2 + k3,
743
+ a*(k0 + k1 - k2 - k3) - 2*I*a_i*k1 + 2*I*a_i*k2,
744
+ (
745
+ a**2*(-k0 - k1 - k2 - k3) +
746
+ a*(4*I*a_i*k0 + 4*I*a_i*k3) +
747
+ 4*a_i**2*k0 + 4*a_i**2*k3),
748
+ (
749
+ a**3*(-k0 - k1 + k2 + k3) +
750
+ a**2*(4*I*a_i*k0 + 2*I*a_i*k1 - 2*I*a_i*k2 - 4*I*a_i*k3) +
751
+ a*(4*a_i**2*k0 - 4*a_i**2*k3))
752
+ ]
753
+ dc = [
754
+ S.One, S.Zero, 2*a_i**2 - 2*a_r**2,
755
+ S.Zero, a_i**4 + 2*a_i**2*a_r**2 + a_r**4]
756
+ n = Add(
757
+ *[x*s**y for x, y in zip(_simpc(nc), range(len(nc))[::-1])])
758
+ d = Add(
759
+ *[x*s**y for x, y in zip(dc, range(len(dc))[::-1])])
760
+ return n/d
761
+
762
+ def _ccpole(t1, k1, s):
763
+ a, k0, a_r, a_i = t1['a'], t1['k'], t1[re], t1[im]
764
+ nc = [k0 + k1, -a*k0 - a*k1 + 2*I*a_i*k0]
765
+ dc = [S.One, -2*a_r, a_i**2 + a_r**2]
766
+ n = Add(
767
+ *[x*s**y for x, y in zip(_simpc(nc), range(len(nc))[::-1])])
768
+ d = Add(
769
+ *[x*s**y for x, y in zip(dc, range(len(dc))[::-1])])
770
+ return n/d
771
+
772
+ def _rspole(t1, k2, s):
773
+ a, k0, a_r, a_i = t1['a'], t1['k'], t1[re], t1[im]
774
+ nc = [k0 + k2, a*k0 - a*k2 - 2*I*a_i*k0]
775
+ dc = [S.One, -2*I*a_i, -a_i**2 - a_r**2]
776
+ n = Add(
777
+ *[x*s**y for x, y in zip(_simpc(nc), range(len(nc))[::-1])])
778
+ d = Add(
779
+ *[x*s**y for x, y in zip(dc, range(len(dc))[::-1])])
780
+ return n/d
781
+
782
+ def _sypole(t1, k3, s):
783
+ a, k0 = t1['a'], t1['k']
784
+ nc = [k0 + k3, a*(k0 - k3)]
785
+ dc = [S.One, S.Zero, -a**2]
786
+ n = Add(
787
+ *[x*s**y for x, y in zip(_simpc(nc), range(len(nc))[::-1])])
788
+ d = Add(
789
+ *[x*s**y for x, y in zip(dc, range(len(dc))[::-1])])
790
+ return n/d
791
+
792
+ def _simplepole(t1, s):
793
+ a, k0 = t1['a'], t1['k']
794
+ n = k0
795
+ d = s - a
796
+ return n/d
797
+
798
+ while len(xm) > 0:
799
+ t1 = xm.pop()
800
+ i_imagsym = None
801
+ i_realsym = None
802
+ i_pointsym = None
803
+ # The following code checks all remaining poles. If t1 is a pole at
804
+ # a+b*I, then we check for a-b*I, -a+b*I, and -a-b*I, and
805
+ # assign the respective indices to i_imagsym, i_realsym, i_pointsym.
806
+ # -a-b*I / i_pointsym only applies if both a and b are != 0.
807
+ for i in range(len(xm)):
808
+ real_eq = t1[re] == xm[i][re]
809
+ realsym = t1[re] == -xm[i][re]
810
+ imag_eq = t1[im] == xm[i][im]
811
+ imagsym = t1[im] == -xm[i][im]
812
+ if realsym and imagsym and t1[re] != 0 and t1[im] != 0:
813
+ i_pointsym = i
814
+ elif realsym and imag_eq and t1[re] != 0:
815
+ i_realsym = i
816
+ elif real_eq and imagsym and t1[im] != 0:
817
+ i_imagsym = i
818
+
819
+ # The next part looks for four possible pole constellations:
820
+ # quad: a+b*I, a-b*I, -a+b*I, -a-b*I
821
+ # cc: a+b*I, a-b*I (a may be zero)
822
+ # quad: a+b*I, -a+b*I (b may be zero)
823
+ # point: a+b*I, -a-b*I (a!=0 and b!=0 is needed, but that has been
824
+ # asserted when finding i_pointsym above.)
825
+ # If none apply, then t1 is a simple pole.
826
+ if (
827
+ i_imagsym is not None and i_realsym is not None
828
+ and i_pointsym is not None):
829
+ results.append(
830
+ _quadpole(t1,
831
+ xm[i_imagsym]['k'], xm[i_realsym]['k'],
832
+ xm[i_pointsym]['k'], s))
833
+ planes.append(Abs(re(t1['a'])))
834
+ # The three additional poles have now been used; to pop them
835
+ # easily we have to do it from the back.
836
+ indices_to_pop = [i_imagsym, i_realsym, i_pointsym]
837
+ indices_to_pop.sort(reverse=True)
838
+ for i in indices_to_pop:
839
+ xm.pop(i)
840
+ elif i_imagsym is not None:
841
+ results.append(_ccpole(t1, xm[i_imagsym]['k'], s))
842
+ planes.append(t1[re])
843
+ xm.pop(i_imagsym)
844
+ elif i_realsym is not None:
845
+ results.append(_rspole(t1, xm[i_realsym]['k'], s))
846
+ planes.append(Abs(t1[re]))
847
+ xm.pop(i_realsym)
848
+ elif i_pointsym is not None:
849
+ results.append(_sypole(t1, xm[i_pointsym]['k'], s))
850
+ planes.append(Abs(t1[re]))
851
+ xm.pop(i_pointsym)
852
+ else:
853
+ results.append(_simplepole(t1, s))
854
+ planes.append(t1[re])
855
+
856
+ return Add(*results), Max(*planes)
857
+
858
+
859
+ @DEBUG_WRAP
860
+ def _laplace_rule_trig(fn, t_, s):
861
+ """
862
+ This rule covers trigonometric factors by splitting everything into a
863
+ sum of exponential functions and collecting complex conjugate poles and
864
+ real symmetric poles.
865
+ """
866
+ t = Dummy('t', real=True)
867
+
868
+ if not fn.has(sin, cos, sinh, cosh):
869
+ return None
870
+
871
+ f, g = _laplace_trig_split(fn.subs(t_, t))
872
+ xm, xn = _laplace_trig_expsum(f, t)
873
+
874
+ if len(xn) > 0:
875
+ # TODO not implemented yet, but also not important
876
+ return None
877
+
878
+ if not g.has(t):
879
+ r, p = _laplace_trig_ltex(xm, t, s)
880
+ return g*r, p, S.true
881
+ else:
882
+ # Just transform `g` and make frequency-shifted copies
883
+ planes = []
884
+ results = []
885
+ G, G_plane, G_cond = _laplace_transform(g, t, s, simplify=False)
886
+ for x1 in xm:
887
+ results.append(x1['k']*G.subs(s, s-x1['a']))
888
+ planes.append(G_plane+re(x1['a']))
889
+ return Add(*results).subs(t, t_), Max(*planes), G_cond
890
+
891
+
892
+ @DEBUG_WRAP
893
+ def _laplace_rule_diff(f, t, s):
894
+ """
895
+ This function looks for derivatives in the time domain and replaces it
896
+ by factors of `s` and initial conditions in the frequency domain. For
897
+ example, if it gets ``(diff(f(t), t), t, s)``, it will compute
898
+ ``s*LaplaceTransform(f(t), t, s) - f(0)``.
899
+ """
900
+
901
+ a = Wild('a', exclude=[t])
902
+ n = Wild('n', exclude=[t])
903
+ g = WildFunction('g')
904
+ ma1 = f.match(a*Derivative(g, (t, n)))
905
+ if ma1 and ma1[n].is_integer:
906
+ m = [z.has(t) for z in ma1[g].args]
907
+ if sum(m) == 1:
908
+ _debug(' rule: time derivative (4.1.8)')
909
+ d = []
910
+ for k in range(ma1[n]):
911
+ if k == 0:
912
+ y = ma1[g].subs(t, 0)
913
+ else:
914
+ y = Derivative(ma1[g], (t, k)).subs(t, 0)
915
+ d.append(s**(ma1[n]-k-1)*y)
916
+ r, pr, cr = _laplace_transform(ma1[g], t, s, simplify=False)
917
+ return (ma1[a]*(s**ma1[n]*r - Add(*d)), pr, cr)
918
+ return None
919
+
920
+
921
+ @DEBUG_WRAP
922
+ def _laplace_rule_sdiff(f, t, s):
923
+ """
924
+ This function looks for multiplications with polynoimials in `t` as they
925
+ correspond to differentiation in the frequency domain. For example, if it
926
+ gets ``(t*f(t), t, s)``, it will compute
927
+ ``-Derivative(LaplaceTransform(f(t), t, s), s)``.
928
+ """
929
+
930
+ if f.is_Mul:
931
+ pfac = [1]
932
+ ofac = [1]
933
+ for fac in Mul.make_args(f):
934
+ if fac.is_polynomial(t):
935
+ pfac.append(fac)
936
+ else:
937
+ ofac.append(fac)
938
+ if len(pfac) > 1:
939
+ pex = prod(pfac)
940
+ pc = Poly(pex, t).all_coeffs()
941
+ N = len(pc)
942
+ if N > 1:
943
+ oex = prod(ofac)
944
+ r_, p_, c_ = _laplace_transform(oex, t, s, simplify=False)
945
+ deri = [r_]
946
+ d1 = False
947
+ try:
948
+ d1 = -diff(deri[-1], s)
949
+ except ValueError:
950
+ d1 = False
951
+ if r_.has(LaplaceTransform):
952
+ for k in range(N-1):
953
+ deri.append((-1)**(k+1)*Derivative(r_, s, k+1))
954
+ elif d1:
955
+ deri.append(d1)
956
+ for k in range(N-2):
957
+ deri.append(-diff(deri[-1], s))
958
+ if d1:
959
+ r = Add(*[pc[N-n-1]*deri[n] for n in range(N)])
960
+ return (r, p_, c_)
961
+ # We still have to cover the possibility that there is a symbolic positive
962
+ # integer exponent.
963
+ n = Wild('n', exclude=[t])
964
+ g = Wild('g')
965
+ if ma1 := f.match(t**n*g):
966
+ if ma1[n].is_integer and ma1[n].is_positive:
967
+ r_, p_, c_ = _laplace_transform(ma1[g], t, s, simplify=False)
968
+ return (-1)**ma1[n]*diff(r_, (s, ma1[n])), p_, c_
969
+ return None
970
+
971
+
972
+ @DEBUG_WRAP
973
+ def _laplace_expand(f, t, s):
974
+ """
975
+ This function tries to expand its argument with successively stronger
976
+ methods: first it will expand on the top level, then it will expand any
977
+ multiplications in depth, then it will try all available expansion methods,
978
+ and finally it will try to expand trigonometric functions.
979
+
980
+ If it can expand, it will then compute the Laplace transform of the
981
+ expanded term.
982
+ """
983
+
984
+ r = expand(f, deep=False)
985
+ if r.is_Add:
986
+ return _laplace_transform(r, t, s, simplify=False)
987
+ r = expand_mul(f)
988
+ if r.is_Add:
989
+ return _laplace_transform(r, t, s, simplify=False)
990
+ r = expand(f)
991
+ if r.is_Add:
992
+ return _laplace_transform(r, t, s, simplify=False)
993
+ if r != f:
994
+ return _laplace_transform(r, t, s, simplify=False)
995
+ r = expand(expand_trig(f))
996
+ if r.is_Add:
997
+ return _laplace_transform(r, t, s, simplify=False)
998
+ return None
999
+
1000
+
1001
+ @DEBUG_WRAP
1002
+ def _laplace_apply_prog_rules(f, t, s):
1003
+ """
1004
+ This function applies all program rules and returns the result if one
1005
+ of them gives a result.
1006
+ """
1007
+
1008
+ prog_rules = [_laplace_rule_heaviside, _laplace_rule_delta,
1009
+ _laplace_rule_timescale, _laplace_rule_exp,
1010
+ _laplace_rule_trig,
1011
+ _laplace_rule_diff, _laplace_rule_sdiff]
1012
+
1013
+ for p_rule in prog_rules:
1014
+ if (L := p_rule(f, t, s)) is not None:
1015
+ return L
1016
+ return None
1017
+
1018
+
1019
+ @DEBUG_WRAP
1020
+ def _laplace_apply_simple_rules(f, t, s):
1021
+ """
1022
+ This function applies all simple rules and returns the result if one
1023
+ of them gives a result.
1024
+ """
1025
+ simple_rules, t_, s_ = _laplace_build_rules()
1026
+ prep_old = ''
1027
+ prep_f = ''
1028
+ for t_dom, s_dom, check, plane, prep in simple_rules:
1029
+ if prep_old != prep:
1030
+ prep_f = prep(f.subs({t: t_}))
1031
+ prep_old = prep
1032
+ ma = prep_f.match(t_dom)
1033
+ if ma:
1034
+ try:
1035
+ c = check.xreplace(ma)
1036
+ except TypeError:
1037
+ # This may happen if the time function has imaginary
1038
+ # numbers in it. Then we give up.
1039
+ continue
1040
+ if c == S.true:
1041
+ return (s_dom.xreplace(ma).subs({s_: s}),
1042
+ plane.xreplace(ma), S.true)
1043
+ return None
1044
+
1045
+
1046
+ @DEBUG_WRAP
1047
+ def _piecewise_to_heaviside(f, t):
1048
+ """
1049
+ This function converts a Piecewise expression to an expression written
1050
+ with Heaviside. It is not exact, but valid in the context of the Laplace
1051
+ transform.
1052
+ """
1053
+ if not t.is_real:
1054
+ r = Dummy('r', real=True)
1055
+ return _piecewise_to_heaviside(f.xreplace({t: r}), r).xreplace({r: t})
1056
+ x = piecewise_exclusive(f)
1057
+ r = []
1058
+ for fn, cond in x.args:
1059
+ # Here we do not need to do many checks because piecewise_exclusive
1060
+ # has a clearly predictable output. However, if any of the conditions
1061
+ # is not relative to t, this function just returns the input argument.
1062
+ if isinstance(cond, Relational) and t in cond.args:
1063
+ if isinstance(cond, (Eq, Ne)):
1064
+ # We do not cover this case; these would be single-point
1065
+ # exceptions that do not play a role in Laplace practice,
1066
+ # except if they contain Dirac impulses, and then we can
1067
+ # expect users to not try to use Piecewise for writing it.
1068
+ return f
1069
+ else:
1070
+ r.append(Heaviside(cond.gts - cond.lts)*fn)
1071
+ elif isinstance(cond, Or) and len(cond.args) == 2:
1072
+ # Or(t<2, t>4), Or(t>4, t<=2), ... in any order with any <= >=
1073
+ for c2 in cond.args:
1074
+ if c2.lhs == t:
1075
+ r.append(Heaviside(c2.gts - c2.lts)*fn)
1076
+ else:
1077
+ return f
1078
+ elif isinstance(cond, And) and len(cond.args) == 2:
1079
+ # And(t>2, t<4), And(t>4, t<=2), ... in any order with any <= >=
1080
+ c0, c1 = cond.args
1081
+ if c0.lhs == t and c1.lhs == t:
1082
+ if '>' in c0.rel_op:
1083
+ c0, c1 = c1, c0
1084
+ r.append(
1085
+ (Heaviside(c1.gts - c1.lts) -
1086
+ Heaviside(c0.lts - c0.gts))*fn)
1087
+ else:
1088
+ return f
1089
+ else:
1090
+ return f
1091
+ return Add(*r)
1092
+
1093
+
1094
+ def laplace_correspondence(f, fdict, /):
1095
+ """
1096
+ This helper function takes a function `f` that is the result of a
1097
+ ``laplace_transform`` or an ``inverse_laplace_transform``. It replaces all
1098
+ unevaluated ``LaplaceTransform(y(t), t, s)`` by `Y(s)` for any `s` and
1099
+ all ``InverseLaplaceTransform(Y(s), s, t)`` by `y(t)` for any `t` if
1100
+ ``fdict`` contains a correspondence ``{y: Y}``.
1101
+
1102
+ Parameters
1103
+ ==========
1104
+
1105
+ f : sympy expression
1106
+ Expression containing unevaluated ``LaplaceTransform`` or
1107
+ ``LaplaceTransform`` objects.
1108
+ fdict : dictionary
1109
+ Dictionary containing one or more function correspondences,
1110
+ e.g., ``{x: X, y: Y}`` meaning that ``X`` and ``Y`` are the
1111
+ Laplace transforms of ``x`` and ``y``, respectively.
1112
+
1113
+ Examples
1114
+ ========
1115
+
1116
+ >>> from sympy import laplace_transform, diff, Function
1117
+ >>> from sympy import laplace_correspondence, inverse_laplace_transform
1118
+ >>> from sympy.abc import t, s
1119
+ >>> y = Function("y")
1120
+ >>> Y = Function("Y")
1121
+ >>> z = Function("z")
1122
+ >>> Z = Function("Z")
1123
+ >>> f = laplace_transform(diff(y(t), t, 1) + z(t), t, s, noconds=True)
1124
+ >>> laplace_correspondence(f, {y: Y, z: Z})
1125
+ s*Y(s) + Z(s) - y(0)
1126
+ >>> f = inverse_laplace_transform(Y(s), s, t)
1127
+ >>> laplace_correspondence(f, {y: Y})
1128
+ y(t)
1129
+ """
1130
+ p = Wild('p')
1131
+ s = Wild('s')
1132
+ t = Wild('t')
1133
+ a = Wild('a')
1134
+ if (
1135
+ not isinstance(f, Expr)
1136
+ or (not f.has(LaplaceTransform)
1137
+ and not f.has(InverseLaplaceTransform))):
1138
+ return f
1139
+ for y, Y in fdict.items():
1140
+ if (
1141
+ (m := f.match(LaplaceTransform(y(a), t, s))) is not None
1142
+ and m[a] == m[t]):
1143
+ return Y(m[s])
1144
+ if (
1145
+ (m := f.match(InverseLaplaceTransform(Y(a), s, t, p)))
1146
+ is not None
1147
+ and m[a] == m[s]):
1148
+ return y(m[t])
1149
+ func = f.func
1150
+ args = [laplace_correspondence(arg, fdict) for arg in f.args]
1151
+ return func(*args)
1152
+
1153
+
1154
+ def laplace_initial_conds(f, t, fdict, /):
1155
+ """
1156
+ This helper function takes a function `f` that is the result of a
1157
+ ``laplace_transform``. It takes an fdict of the form ``{y: [1, 4, 2]}``,
1158
+ where the values in the list are the initial value, the initial slope, the
1159
+ initial second derivative, etc., of the function `y(t)`, and replaces all
1160
+ unevaluated initial conditions.
1161
+
1162
+ Parameters
1163
+ ==========
1164
+
1165
+ f : sympy expression
1166
+ Expression containing initial conditions of unevaluated functions.
1167
+ t : sympy expression
1168
+ Variable for which the initial conditions are to be applied.
1169
+ fdict : dictionary
1170
+ Dictionary containing a list of initial conditions for every
1171
+ function, e.g., ``{y: [0, 1, 2], x: [3, 4, 5]}``. The order
1172
+ of derivatives is ascending, so `0`, `1`, `2` are `y(0)`, `y'(0)`,
1173
+ and `y''(0)`, respectively.
1174
+
1175
+ Examples
1176
+ ========
1177
+
1178
+ >>> from sympy import laplace_transform, diff, Function
1179
+ >>> from sympy import laplace_correspondence, laplace_initial_conds
1180
+ >>> from sympy.abc import t, s
1181
+ >>> y = Function("y")
1182
+ >>> Y = Function("Y")
1183
+ >>> f = laplace_transform(diff(y(t), t, 3), t, s, noconds=True)
1184
+ >>> g = laplace_correspondence(f, {y: Y})
1185
+ >>> laplace_initial_conds(g, t, {y: [2, 4, 8, 16, 32]})
1186
+ s**3*Y(s) - 2*s**2 - 4*s - 8
1187
+ """
1188
+ for y, ic in fdict.items():
1189
+ for k in range(len(ic)):
1190
+ if k == 0:
1191
+ f = f.replace(y(0), ic[0])
1192
+ elif k == 1:
1193
+ f = f.replace(Subs(Derivative(y(t), t), t, 0), ic[1])
1194
+ else:
1195
+ f = f.replace(Subs(Derivative(y(t), (t, k)), t, 0), ic[k])
1196
+ return f
1197
+
1198
+
1199
+ @DEBUG_WRAP
1200
+ def _laplace_transform(fn, t_, s_, *, simplify):
1201
+ """
1202
+ Front-end function of the Laplace transform. It tries to apply all known
1203
+ rules recursively, and if everything else fails, it tries to integrate.
1204
+ """
1205
+
1206
+ terms_t = Add.make_args(fn)
1207
+ terms_s = []
1208
+ terms = []
1209
+ planes = []
1210
+ conditions = []
1211
+
1212
+ for ff in terms_t:
1213
+ k, ft = ff.as_independent(t_, as_Add=False)
1214
+ if ft.has(SingularityFunction):
1215
+ _terms = Add.make_args(ft.rewrite(Heaviside))
1216
+ for _term in _terms:
1217
+ k1, f1 = _term.as_independent(t_, as_Add=False)
1218
+ terms.append((k*k1, f1))
1219
+ elif ft.func == Piecewise and not ft.has(DiracDelta(t_)):
1220
+ _terms = Add.make_args(_piecewise_to_heaviside(ft, t_))
1221
+ for _term in _terms:
1222
+ k1, f1 = _term.as_independent(t_, as_Add=False)
1223
+ terms.append((k*k1, f1))
1224
+ else:
1225
+ terms.append((k, ft))
1226
+
1227
+ for k, ft in terms:
1228
+ if ft.has(SingularityFunction):
1229
+ r = (LaplaceTransform(ft, t_, s_), S.NegativeInfinity, True)
1230
+ else:
1231
+ if ft.has(Heaviside(t_)) and not ft.has(DiracDelta(t_)):
1232
+ # For t>=0, Heaviside(t)=1 can be used, except if there is also
1233
+ # a DiracDelta(t) present, in which case removing Heaviside(t)
1234
+ # is unnecessary because _laplace_rule_delta can deal with it.
1235
+ ft = ft.subs(Heaviside(t_), 1)
1236
+ if (
1237
+ (r := _laplace_apply_simple_rules(ft, t_, s_))
1238
+ is not None or
1239
+ (r := _laplace_apply_prog_rules(ft, t_, s_))
1240
+ is not None or
1241
+ (r := _laplace_expand(ft, t_, s_)) is not None):
1242
+ pass
1243
+ elif any(undef.has(t_) for undef in ft.atoms(AppliedUndef)):
1244
+ # If there are undefined functions f(t) then integration is
1245
+ # unlikely to do anything useful so we skip it and given an
1246
+ # unevaluated LaplaceTransform.
1247
+ r = (LaplaceTransform(ft, t_, s_), S.NegativeInfinity, True)
1248
+ elif (r := _laplace_transform_integration(
1249
+ ft, t_, s_, simplify=simplify)) is not None:
1250
+ pass
1251
+ else:
1252
+ r = (LaplaceTransform(ft, t_, s_), S.NegativeInfinity, True)
1253
+ (ri_, pi_, ci_) = r
1254
+ terms_s.append(k*ri_)
1255
+ planes.append(pi_)
1256
+ conditions.append(ci_)
1257
+
1258
+ result = Add(*terms_s)
1259
+ if simplify:
1260
+ result = result.simplify(doit=False)
1261
+ plane = Max(*planes)
1262
+ condition = And(*conditions)
1263
+
1264
+ return result, plane, condition
1265
+
1266
+
1267
+ class LaplaceTransform(IntegralTransform):
1268
+ """
1269
+ Class representing unevaluated Laplace transforms.
1270
+
1271
+ For usage of this class, see the :class:`IntegralTransform` docstring.
1272
+
1273
+ For how to compute Laplace transforms, see the :func:`laplace_transform`
1274
+ docstring.
1275
+
1276
+ If this is called with ``.doit()``, it returns the Laplace transform as an
1277
+ expression. If it is called with ``.doit(noconds=False)``, it returns a
1278
+ tuple containing the same expression, a convergence plane, and conditions.
1279
+ """
1280
+
1281
+ _name = 'Laplace'
1282
+
1283
+ def _compute_transform(self, f, t, s, **hints):
1284
+ _simplify = hints.get('simplify', False)
1285
+ LT = _laplace_transform_integration(f, t, s, simplify=_simplify)
1286
+ return LT
1287
+
1288
+ def _as_integral(self, f, t, s):
1289
+ return Integral(f*exp(-s*t), (t, S.Zero, S.Infinity))
1290
+
1291
+ def doit(self, **hints):
1292
+ """
1293
+ Try to evaluate the transform in closed form.
1294
+
1295
+ Explanation
1296
+ ===========
1297
+
1298
+ Standard hints are the following:
1299
+ - ``noconds``: if True, do not return convergence conditions. The
1300
+ default setting is `True`.
1301
+ - ``simplify``: if True, it simplifies the final result. The
1302
+ default setting is `False`.
1303
+ """
1304
+ _noconds = hints.get('noconds', True)
1305
+ _simplify = hints.get('simplify', False)
1306
+
1307
+ debugf('[LT doit] (%s, %s, %s)', (self.function,
1308
+ self.function_variable,
1309
+ self.transform_variable))
1310
+
1311
+ t_ = self.function_variable
1312
+ s_ = self.transform_variable
1313
+ fn = self.function
1314
+
1315
+ r = _laplace_transform(fn, t_, s_, simplify=_simplify)
1316
+
1317
+ if _noconds:
1318
+ return r[0]
1319
+ else:
1320
+ return r
1321
+
1322
+
1323
+ def laplace_transform(f, t, s, legacy_matrix=True, **hints):
1324
+ r"""
1325
+ Compute the Laplace Transform `F(s)` of `f(t)`,
1326
+
1327
+ .. math :: F(s) = \int_{0^{-}}^\infty e^{-st} f(t) \mathrm{d}t.
1328
+
1329
+ Explanation
1330
+ ===========
1331
+
1332
+ For all sensible functions, this converges absolutely in a
1333
+ half-plane
1334
+
1335
+ .. math :: a < \operatorname{Re}(s)
1336
+
1337
+ This function returns ``(F, a, cond)`` where ``F`` is the Laplace
1338
+ transform of ``f``, `a` is the half-plane of convergence, and `cond` are
1339
+ auxiliary convergence conditions.
1340
+
1341
+ The implementation is rule-based, and if you are interested in which
1342
+ rules are applied, and whether integration is attempted, you can switch
1343
+ debug information on by setting ``sympy.SYMPY_DEBUG=True``. The numbers
1344
+ of the rules in the debug information (and the code) refer to Bateman's
1345
+ Tables of Integral Transforms [1].
1346
+
1347
+ The lower bound is `0-`, meaning that this bound should be approached
1348
+ from the lower side. This is only necessary if distributions are involved.
1349
+ At present, it is only done if `f(t)` contains ``DiracDelta``, in which
1350
+ case the Laplace transform is computed implicitly as
1351
+
1352
+ .. math ::
1353
+ F(s) = \lim_{\tau\to 0^{-}} \int_{\tau}^\infty e^{-st}
1354
+ f(t) \mathrm{d}t
1355
+
1356
+ by applying rules.
1357
+
1358
+ If the Laplace transform cannot be fully computed in closed form, this
1359
+ function returns expressions containing unevaluated
1360
+ :class:`LaplaceTransform` objects.
1361
+
1362
+ For a description of possible hints, refer to the docstring of
1363
+ :func:`sympy.integrals.transforms.IntegralTransform.doit`. If
1364
+ ``noconds=True``, only `F` will be returned (i.e. not ``cond``, and also
1365
+ not the plane ``a``).
1366
+
1367
+ .. deprecated:: 1.9
1368
+ Legacy behavior for matrices where ``laplace_transform`` with
1369
+ ``noconds=False`` (the default) returns a Matrix whose elements are
1370
+ tuples. The behavior of ``laplace_transform`` for matrices will change
1371
+ in a future release of SymPy to return a tuple of the transformed
1372
+ Matrix and the convergence conditions for the matrix as a whole. Use
1373
+ ``legacy_matrix=False`` to enable the new behavior.
1374
+
1375
+ Examples
1376
+ ========
1377
+
1378
+ >>> from sympy import DiracDelta, exp, laplace_transform
1379
+ >>> from sympy.abc import t, s, a
1380
+ >>> laplace_transform(t**4, t, s)
1381
+ (24/s**5, 0, True)
1382
+ >>> laplace_transform(t**a, t, s)
1383
+ (gamma(a + 1)/(s*s**a), 0, re(a) > -1)
1384
+ >>> laplace_transform(DiracDelta(t)-a*exp(-a*t), t, s, simplify=True)
1385
+ (s/(a + s), -re(a), True)
1386
+
1387
+ There are also helper functions that make it easy to solve differential
1388
+ equations by Laplace transform. For example, to solve
1389
+
1390
+ .. math :: m x''(t) + d x'(t) + k x(t) = 0
1391
+
1392
+ with initial value `0` and initial derivative `v`:
1393
+
1394
+ >>> from sympy import Function, laplace_correspondence, diff, solve
1395
+ >>> from sympy import laplace_initial_conds, inverse_laplace_transform
1396
+ >>> from sympy.abc import d, k, m, v
1397
+ >>> x = Function('x')
1398
+ >>> X = Function('X')
1399
+ >>> f = m*diff(x(t), t, 2) + d*diff(x(t), t) + k*x(t)
1400
+ >>> F = laplace_transform(f, t, s, noconds=True)
1401
+ >>> F = laplace_correspondence(F, {x: X})
1402
+ >>> F = laplace_initial_conds(F, t, {x: [0, v]})
1403
+ >>> F
1404
+ d*s*X(s) + k*X(s) + m*(s**2*X(s) - v)
1405
+ >>> Xs = solve(F, X(s))[0]
1406
+ >>> Xs
1407
+ m*v/(d*s + k + m*s**2)
1408
+ >>> inverse_laplace_transform(Xs, s, t)
1409
+ 2*v*exp(-d*t/(2*m))*sin(t*sqrt((-d**2 + 4*k*m)/m**2)/2)*Heaviside(t)/sqrt((-d**2 + 4*k*m)/m**2)
1410
+
1411
+ References
1412
+ ==========
1413
+
1414
+ .. [1] Erdelyi, A. (ed.), Tables of Integral Transforms, Volume 1,
1415
+ Bateman Manuscript Prooject, McGraw-Hill (1954), available:
1416
+ https://resolver.caltech.edu/CaltechAUTHORS:20140123-101456353
1417
+
1418
+ See Also
1419
+ ========
1420
+
1421
+ inverse_laplace_transform, mellin_transform, fourier_transform
1422
+ hankel_transform, inverse_hankel_transform
1423
+
1424
+ """
1425
+
1426
+ _noconds = hints.get('noconds', False)
1427
+ _simplify = hints.get('simplify', False)
1428
+
1429
+ if isinstance(f, MatrixBase) and hasattr(f, 'applyfunc'):
1430
+
1431
+ conds = not hints.get('noconds', False)
1432
+
1433
+ if conds and legacy_matrix:
1434
+ adt = 'deprecated-laplace-transform-matrix'
1435
+ sympy_deprecation_warning(
1436
+ """
1437
+ Calling laplace_transform() on a Matrix with noconds=False (the default) is
1438
+ deprecated. Either noconds=True or use legacy_matrix=False to get the new
1439
+ behavior.
1440
+ """,
1441
+ deprecated_since_version='1.9',
1442
+ active_deprecations_target=adt,
1443
+ )
1444
+ # Temporarily disable the deprecation warning for non-Expr objects
1445
+ # in Matrix
1446
+ with ignore_warnings(SymPyDeprecationWarning):
1447
+ return f.applyfunc(
1448
+ lambda fij: laplace_transform(fij, t, s, **hints))
1449
+ else:
1450
+ elements_trans = [laplace_transform(
1451
+ fij, t, s, **hints) for fij in f]
1452
+ if conds:
1453
+ elements, avals, conditions = zip(*elements_trans)
1454
+ f_laplace = type(f)(*f.shape, elements)
1455
+ return f_laplace, Max(*avals), And(*conditions)
1456
+ else:
1457
+ return type(f)(*f.shape, elements_trans)
1458
+
1459
+ LT, p, c = LaplaceTransform(f, t, s).doit(noconds=False,
1460
+ simplify=_simplify)
1461
+
1462
+ if not _noconds:
1463
+ return LT, p, c
1464
+ else:
1465
+ return LT
1466
+
1467
+
1468
+ @DEBUG_WRAP
1469
+ def _inverse_laplace_transform_integration(F, s, t_, plane, *, simplify):
1470
+ """ The backend function for inverse Laplace transforms. """
1471
+ from sympy.integrals.meijerint import meijerint_inversion, _get_coeff_exp
1472
+ from sympy.integrals.transforms import inverse_mellin_transform
1473
+
1474
+ # There are two strategies we can try:
1475
+ # 1) Use inverse mellin transform, related by a simple change of variables.
1476
+ # 2) Use the inversion integral.
1477
+
1478
+ t = Dummy('t', real=True)
1479
+
1480
+ def pw_simp(*args):
1481
+ """ Simplify a piecewise expression from hyperexpand. """
1482
+ if len(args) != 3:
1483
+ return Piecewise(*args)
1484
+ arg = args[2].args[0].argument
1485
+ coeff, exponent = _get_coeff_exp(arg, t)
1486
+ e1 = args[0].args[0]
1487
+ e2 = args[1].args[0]
1488
+ return (
1489
+ Heaviside(1/Abs(coeff) - t**exponent)*e1 +
1490
+ Heaviside(t**exponent - 1/Abs(coeff))*e2)
1491
+
1492
+ if F.is_rational_function(s):
1493
+ F = F.apart(s)
1494
+
1495
+ if F.is_Add:
1496
+ f = Add(
1497
+ *[_inverse_laplace_transform_integration(X, s, t, plane, simplify)
1498
+ for X in F.args])
1499
+ return _simplify(f.subs(t, t_), simplify), True
1500
+
1501
+ try:
1502
+ f, cond = inverse_mellin_transform(F, s, exp(-t), (None, S.Infinity),
1503
+ needeval=True, noconds=False)
1504
+ except IntegralTransformError:
1505
+ f = None
1506
+
1507
+ if f is None:
1508
+ f = meijerint_inversion(F, s, t)
1509
+ if f is None:
1510
+ return None
1511
+ if f.is_Piecewise:
1512
+ f, cond = f.args[0]
1513
+ if f.has(Integral):
1514
+ return None
1515
+ else:
1516
+ cond = S.true
1517
+ f = f.replace(Piecewise, pw_simp)
1518
+
1519
+ if f.is_Piecewise:
1520
+ # many of the functions called below can't work with piecewise
1521
+ # (b/c it has a bool in args)
1522
+ return f.subs(t, t_), cond
1523
+
1524
+ u = Dummy('u')
1525
+
1526
+ def simp_heaviside(arg, H0=S.Half):
1527
+ a = arg.subs(exp(-t), u)
1528
+ if a.has(t):
1529
+ return Heaviside(arg, H0)
1530
+ from sympy.solvers.inequalities import _solve_inequality
1531
+ rel = _solve_inequality(a > 0, u)
1532
+ if rel.lts == u:
1533
+ k = log(rel.gts)
1534
+ return Heaviside(t + k, H0)
1535
+ else:
1536
+ k = log(rel.lts)
1537
+ return Heaviside(-(t + k), H0)
1538
+
1539
+ f = f.replace(Heaviside, simp_heaviside)
1540
+
1541
+ def simp_exp(arg):
1542
+ return expand_complex(exp(arg))
1543
+
1544
+ f = f.replace(exp, simp_exp)
1545
+
1546
+ return _simplify(f.subs(t, t_), simplify), cond
1547
+
1548
+
1549
+ @DEBUG_WRAP
1550
+ def _complete_the_square_in_denom(f, s):
1551
+ from sympy.simplify.radsimp import fraction
1552
+ [n, d] = fraction(f)
1553
+ if d.is_polynomial(s):
1554
+ cf = d.as_poly(s).all_coeffs()
1555
+ if len(cf) == 3:
1556
+ a, b, c = cf
1557
+ d = a*((s+b/(2*a))**2+c/a-(b/(2*a))**2)
1558
+ return n/d
1559
+
1560
+
1561
+ @cacheit
1562
+ def _inverse_laplace_build_rules():
1563
+ """
1564
+ This is an internal helper function that returns the table of inverse
1565
+ Laplace transform rules in terms of the time variable `t` and the
1566
+ frequency variable `s`. It is used by `_inverse_laplace_apply_rules`.
1567
+ """
1568
+ s = Dummy('s')
1569
+ t = Dummy('t')
1570
+ a = Wild('a', exclude=[s])
1571
+ b = Wild('b', exclude=[s])
1572
+ c = Wild('c', exclude=[s])
1573
+
1574
+ _debug('_inverse_laplace_build_rules is building rules')
1575
+
1576
+ def _frac(f, s):
1577
+ try:
1578
+ return f.factor(s)
1579
+ except PolynomialError:
1580
+ return f
1581
+
1582
+ def same(f): return f
1583
+ # This list is sorted according to the prep function needed.
1584
+ _ILT_rules = [
1585
+ (a/s, a, S.true, same, 1),
1586
+ (
1587
+ b*(s+a)**(-c), t**(c-1)*exp(-a*t)/gamma(c),
1588
+ S.true, same, 1),
1589
+ (1/(s**2+a**2)**2, (sin(a*t) - a*t*cos(a*t))/(2*a**3),
1590
+ S.true, same, 1),
1591
+ # The next two rules must be there in that order. For the second
1592
+ # one, the condition would be a != 0 or, respectively, to take the
1593
+ # limit a -> 0 after the transform if a == 0. It is much simpler if
1594
+ # the case a == 0 has its own rule.
1595
+ (1/(s**b), t**(b - 1)/gamma(b), S.true, same, 1),
1596
+ (1/(s*(s+a)**b), lowergamma(b, a*t)/(a**b*gamma(b)),
1597
+ S.true, same, 1)
1598
+ ]
1599
+ return _ILT_rules, s, t
1600
+
1601
+
1602
+ @DEBUG_WRAP
1603
+ def _inverse_laplace_apply_simple_rules(f, s, t):
1604
+ """
1605
+ Helper function for the class InverseLaplaceTransform.
1606
+ """
1607
+ if f == 1:
1608
+ _debug(' rule: 1 o---o DiracDelta()')
1609
+ return DiracDelta(t), S.true
1610
+
1611
+ _ILT_rules, s_, t_ = _inverse_laplace_build_rules()
1612
+ _prep = ''
1613
+ fsubs = f.subs({s: s_})
1614
+
1615
+ for s_dom, t_dom, check, prep, fac in _ILT_rules:
1616
+ if _prep != (prep, fac):
1617
+ _F = prep(fsubs*fac)
1618
+ _prep = (prep, fac)
1619
+ ma = _F.match(s_dom)
1620
+ if ma:
1621
+ c = check
1622
+ if c is not S.true:
1623
+ args = [x.xreplace(ma) for x in c[0]]
1624
+ c = c[1](*args)
1625
+ if c == S.true:
1626
+ return Heaviside(t)*t_dom.xreplace(ma).subs({t_: t}), S.true
1627
+
1628
+ return None
1629
+
1630
+
1631
+ @DEBUG_WRAP
1632
+ def _inverse_laplace_diff(f, s, t, plane):
1633
+ """
1634
+ Helper function for the class InverseLaplaceTransform.
1635
+ """
1636
+ a = Wild('a', exclude=[s])
1637
+ n = Wild('n', exclude=[s])
1638
+ g = Wild('g')
1639
+ ma = f.match(a*Derivative(g, (s, n)))
1640
+ if ma and ma[n].is_integer:
1641
+ _debug(' rule: t**n*f(t) o---o (-1)**n*diff(F(s), s, n)')
1642
+ r, c = _inverse_laplace_transform(
1643
+ ma[g], s, t, plane, simplify=False, dorational=False)
1644
+ return (-t)**ma[n]*r, c
1645
+ return None
1646
+
1647
+
1648
+ @DEBUG_WRAP
1649
+ def _inverse_laplace_time_shift(F, s, t, plane):
1650
+ """
1651
+ Helper function for the class InverseLaplaceTransform.
1652
+ """
1653
+ a = Wild('a', exclude=[s])
1654
+ g = Wild('g')
1655
+
1656
+ if not F.has(s):
1657
+ return F*DiracDelta(t), S.true
1658
+ if not F.has(exp):
1659
+ return None
1660
+
1661
+ ma1 = F.match(exp(a*s))
1662
+ if ma1:
1663
+ if ma1[a].is_negative:
1664
+ _debug(' rule: exp(-a*s) o---o DiracDelta(t-a)')
1665
+ return DiracDelta(t+ma1[a]), S.true
1666
+ else:
1667
+ return InverseLaplaceTransform(F, s, t, plane), S.true
1668
+
1669
+ ma1 = F.match(exp(a*s)*g)
1670
+ if ma1:
1671
+ if ma1[a].is_negative:
1672
+ _debug(' rule: exp(-a*s)*F(s) o---o Heaviside(t-a)*f(t-a)')
1673
+ return _inverse_laplace_transform(
1674
+ ma1[g], s, t+ma1[a], plane, simplify=False, dorational=True)
1675
+ else:
1676
+ return InverseLaplaceTransform(F, s, t, plane), S.true
1677
+ return None
1678
+
1679
+
1680
+ @DEBUG_WRAP
1681
+ def _inverse_laplace_freq_shift(F, s, t, plane):
1682
+ """
1683
+ Helper function for the class InverseLaplaceTransform.
1684
+ """
1685
+ if not F.has(s):
1686
+ return F*DiracDelta(t), S.true
1687
+ if len(args := F.args) == 1:
1688
+ a = Wild('a', exclude=[s])
1689
+ if (ma := args[0].match(s-a)) and re(ma[a]).is_positive:
1690
+ _debug(' rule: F(s-a) o---o exp(-a*t)*f(t)')
1691
+ return (
1692
+ exp(-ma[a]*t) *
1693
+ InverseLaplaceTransform(F.func(s), s, t, plane), S.true)
1694
+ return None
1695
+
1696
+
1697
+ @DEBUG_WRAP
1698
+ def _inverse_laplace_time_diff(F, s, t, plane):
1699
+ """
1700
+ Helper function for the class InverseLaplaceTransform.
1701
+ """
1702
+ n = Wild('n', exclude=[s])
1703
+ g = Wild('g')
1704
+
1705
+ ma1 = F.match(s**n*g)
1706
+ if ma1 and ma1[n].is_integer and ma1[n].is_positive:
1707
+ _debug(' rule: s**n*F(s) o---o diff(f(t), t, n)')
1708
+ r, c = _inverse_laplace_transform(
1709
+ ma1[g], s, t, plane, simplify=False, dorational=True)
1710
+ r = r.replace(Heaviside(t), 1)
1711
+ if r.has(InverseLaplaceTransform):
1712
+ return diff(r, t, ma1[n]), c
1713
+ else:
1714
+ return Heaviside(t)*diff(r, t, ma1[n]), c
1715
+ return None
1716
+
1717
+
1718
+ @DEBUG_WRAP
1719
+ def _inverse_laplace_irrational(fn, s, t, plane):
1720
+ """
1721
+ Helper function for the class InverseLaplaceTransform.
1722
+ """
1723
+
1724
+ a = Wild('a', exclude=[s])
1725
+ b = Wild('b', exclude=[s])
1726
+ m = Wild('m', exclude=[s])
1727
+ n = Wild('n', exclude=[s])
1728
+
1729
+ result = None
1730
+ condition = S.true
1731
+
1732
+ fa = fn.as_ordered_factors()
1733
+
1734
+ ma = [x.match((a*s**m+b)**n) for x in fa]
1735
+
1736
+ if None in ma:
1737
+ return None
1738
+
1739
+ constants = S.One
1740
+ zeros = []
1741
+ poles = []
1742
+ rest = []
1743
+
1744
+ for term in ma:
1745
+ if term[a] == 0:
1746
+ constants = constants*term
1747
+ elif term[n].is_positive:
1748
+ zeros.append(term)
1749
+ elif term[n].is_negative:
1750
+ poles.append(term)
1751
+ else:
1752
+ rest.append(term)
1753
+
1754
+ # The code below assumes that the poles are sorted in a specific way:
1755
+ poles = sorted(poles, key=lambda x: (x[n], x[b] != 0, x[b]))
1756
+ zeros = sorted(zeros, key=lambda x: (x[n], x[b] != 0, x[b]))
1757
+
1758
+ if len(rest) != 0:
1759
+ return None
1760
+
1761
+ if len(poles) == 1 and len(zeros) == 0:
1762
+ if poles[0][n] == -1 and poles[0][m] == S.Half:
1763
+ # 1/(a0*sqrt(s)+b0) == 1/a0 * 1/(sqrt(s)+b0/a0)
1764
+ a_ = poles[0][b]/poles[0][a]
1765
+ k_ = 1/poles[0][a]*constants
1766
+ if a_.is_positive:
1767
+ result = (
1768
+ k_/sqrt(pi)/sqrt(t) -
1769
+ k_*a_*exp(a_**2*t)*erfc(a_*sqrt(t)))
1770
+ _debug(' rule 5.3.4')
1771
+ elif poles[0][n] == -2 and poles[0][m] == S.Half:
1772
+ # 1/(a0*sqrt(s)+b0)**2 == 1/a0**2 * 1/(sqrt(s)+b0/a0)**2
1773
+ a_sq = poles[0][b]/poles[0][a]
1774
+ a_ = a_sq**2
1775
+ k_ = 1/poles[0][a]**2*constants
1776
+ if a_sq.is_positive:
1777
+ result = (
1778
+ k_*(1 - 2/sqrt(pi)*sqrt(a_)*sqrt(t) +
1779
+ (1-2*a_*t)*exp(a_*t)*(erf(sqrt(a_)*sqrt(t))-1)))
1780
+ _debug(' rule 5.3.10')
1781
+ elif poles[0][n] == -3 and poles[0][m] == S.Half:
1782
+ # 1/(a0*sqrt(s)+b0)**3 == 1/a0**3 * 1/(sqrt(s)+b0/a0)**3
1783
+ a_ = poles[0][b]/poles[0][a]
1784
+ k_ = 1/poles[0][a]**3*constants
1785
+ if a_.is_positive:
1786
+ result = (
1787
+ k_*(2/sqrt(pi)*(a_**2*t+1)*sqrt(t) -
1788
+ a_*t*exp(a_**2*t)*(2*a_**2*t+3)*erfc(a_*sqrt(t))))
1789
+ _debug(' rule 5.3.13')
1790
+ elif poles[0][n] == -4 and poles[0][m] == S.Half:
1791
+ # 1/(a0*sqrt(s)+b0)**4 == 1/a0**4 * 1/(sqrt(s)+b0/a0)**4
1792
+ a_ = poles[0][b]/poles[0][a]
1793
+ k_ = 1/poles[0][a]**4*constants/3
1794
+ if a_.is_positive:
1795
+ result = (
1796
+ k_*(t*(4*a_**4*t**2+12*a_**2*t+3)*exp(a_**2*t) *
1797
+ erfc(a_*sqrt(t)) -
1798
+ 2/sqrt(pi)*a_**3*t**(S(5)/2)*(2*a_**2*t+5)))
1799
+ _debug(' rule 5.3.16')
1800
+ elif poles[0][n] == -S.Half and poles[0][m] == 2:
1801
+ # 1/sqrt(a0*s**2+b0) == 1/sqrt(a0) * 1/sqrt(s**2+b0/a0)
1802
+ a_ = sqrt(poles[0][b]/poles[0][a])
1803
+ k_ = 1/sqrt(poles[0][a])*constants
1804
+ result = (k_*(besselj(0, a_*t)))
1805
+ _debug(' rule 5.3.35/44')
1806
+
1807
+ elif len(poles) == 1 and len(zeros) == 1:
1808
+ if (
1809
+ poles[0][n] == -3 and poles[0][m] == S.Half and
1810
+ zeros[0][n] == S.Half and zeros[0][b] == 0):
1811
+ # sqrt(az*s)/(ap*sqrt(s+bp)**3)
1812
+ # == sqrt(az)/ap * sqrt(s)/(sqrt(s+bp)**3)
1813
+ a_ = poles[0][b]
1814
+ k_ = sqrt(zeros[0][a])/poles[0][a]*constants
1815
+ result = (
1816
+ k_*(2*a_**4*t**2+5*a_**2*t+1)*exp(a_**2*t) *
1817
+ erfc(a_*sqrt(t)) - 2/sqrt(pi)*a_*(a_**2*t+2)*sqrt(t))
1818
+ _debug(' rule 5.3.14')
1819
+ if (
1820
+ poles[0][n] == -1 and poles[0][m] == 1 and
1821
+ zeros[0][n] == S.Half and zeros[0][m] == 1):
1822
+ # sqrt(az*s+bz)/(ap*s+bp)
1823
+ # == sqrt(az)/ap * (sqrt(s+bz/az)/(s+bp/ap))
1824
+ a_ = zeros[0][b]/zeros[0][a]
1825
+ b_ = poles[0][b]/poles[0][a]
1826
+ k_ = sqrt(zeros[0][a])/poles[0][a]*constants
1827
+ result = (
1828
+ k_*(exp(-a_*t)/sqrt(t)/sqrt(pi)+sqrt(a_-b_) *
1829
+ exp(-b_*t)*erf(sqrt(a_-b_)*sqrt(t))))
1830
+ _debug(' rule 5.3.22')
1831
+
1832
+ elif len(poles) == 2 and len(zeros) == 0:
1833
+ if (
1834
+ poles[0][n] == -1 and poles[0][m] == 1 and
1835
+ poles[1][n] == -S.Half and poles[1][m] == 1 and
1836
+ poles[1][b] == 0):
1837
+ # 1/((a0*s+b0)*sqrt(a1*s))
1838
+ # == 1/(a0*sqrt(a1)) * 1/((s+b0/a0)*sqrt(s))
1839
+ a_ = -poles[0][b]/poles[0][a]
1840
+ k_ = 1/sqrt(poles[1][a])/poles[0][a]*constants
1841
+ if a_.is_positive:
1842
+ result = (k_/sqrt(a_)*exp(a_*t)*erf(sqrt(a_)*sqrt(t)))
1843
+ _debug(' rule 5.3.1')
1844
+ elif (
1845
+ poles[0][n] == -1 and poles[0][m] == 1 and poles[0][b] == 0 and
1846
+ poles[1][n] == -1 and poles[1][m] == S.Half):
1847
+ # 1/(a0*s*(a1*sqrt(s)+b1))
1848
+ # == 1/(a0*a1) * 1/(s*(sqrt(s)+b1/a1))
1849
+ a_ = poles[1][b]/poles[1][a]
1850
+ k_ = 1/poles[0][a]/poles[1][a]/a_*constants
1851
+ if a_.is_positive:
1852
+ result = k_*(1-exp(a_**2*t)*erfc(a_*sqrt(t)))
1853
+ _debug(' rule 5.3.5')
1854
+ elif (
1855
+ poles[0][n] == -1 and poles[0][m] == S.Half and
1856
+ poles[1][n] == -S.Half and poles[1][m] == 1 and
1857
+ poles[1][b] == 0):
1858
+ # 1/((a0*sqrt(s)+b0)*(sqrt(a1*s))
1859
+ # == 1/(a0*sqrt(a1)) * 1/((sqrt(s)+b0/a0)"sqrt(s))
1860
+ a_ = poles[0][b]/poles[0][a]
1861
+ k_ = 1/(poles[0][a]*sqrt(poles[1][a]))*constants
1862
+ if a_.is_positive:
1863
+ result = k_*exp(a_**2*t)*erfc(a_*sqrt(t))
1864
+ _debug(' rule 5.3.7')
1865
+ elif (
1866
+ poles[0][n] == -S(3)/2 and poles[0][m] == 1 and
1867
+ poles[0][b] == 0 and poles[1][n] == -1 and
1868
+ poles[1][m] == S.Half):
1869
+ # 1/((a0**(3/2)*s**(3/2))*(a1*sqrt(s)+b1))
1870
+ # == 1/(a0**(3/2)*a1) 1/((s**(3/2))*(sqrt(s)+b1/a1))
1871
+ # Note that Bateman54 5.3 (8) is incorrect; there (sqrt(p)+a)
1872
+ # should be (sqrt(p)+a)**(-1).
1873
+ a_ = poles[1][b]/poles[1][a]
1874
+ k_ = 1/(poles[0][a]**(S(3)/2)*poles[1][a])/a_**2*constants
1875
+ if a_.is_positive:
1876
+ result = (
1877
+ k_*(2/sqrt(pi)*a_*sqrt(t)+exp(a_**2*t)*erfc(a_*sqrt(t))-1))
1878
+ _debug(' rule 5.3.8')
1879
+ elif (
1880
+ poles[0][n] == -2 and poles[0][m] == S.Half and
1881
+ poles[1][n] == -1 and poles[1][m] == 1 and
1882
+ poles[1][b] == 0):
1883
+ # 1/((a0*sqrt(s)+b0)**2*a1*s)
1884
+ # == 1/a0**2/a1 * 1/(sqrt(s)+b0/a0)**2/s
1885
+ a_sq = poles[0][b]/poles[0][a]
1886
+ a_ = a_sq**2
1887
+ k_ = 1/poles[0][a]**2/poles[1][a]*constants
1888
+ if a_sq.is_positive:
1889
+ result = (
1890
+ k_*(1/a_ + (2*t-1/a_)*exp(a_*t)*erfc(sqrt(a_)*sqrt(t)) -
1891
+ 2/sqrt(pi)/sqrt(a_)*sqrt(t)))
1892
+ _debug(' rule 5.3.11')
1893
+ elif (
1894
+ poles[0][n] == -2 and poles[0][m] == S.Half and
1895
+ poles[1][n] == -S.Half and poles[1][m] == 1 and
1896
+ poles[1][b] == 0):
1897
+ # 1/((a0*sqrt(s)+b0)**2*sqrt(a1*s))
1898
+ # == 1/a0**2/sqrt(a1) * 1/(sqrt(s)+b0/a0)**2/sqrt(s)
1899
+ a_ = poles[0][b]/poles[0][a]
1900
+ k_ = 1/poles[0][a]**2/sqrt(poles[1][a])*constants
1901
+ if a_.is_positive:
1902
+ result = (
1903
+ k_*(2/sqrt(pi)*sqrt(t) -
1904
+ 2*a_*t*exp(a_**2*t)*erfc(a_*sqrt(t))))
1905
+ _debug(' rule 5.3.12')
1906
+ elif (
1907
+ poles[0][n] == -3 and poles[0][m] == S.Half and
1908
+ poles[1][n] == -S.Half and poles[1][m] == 1 and
1909
+ poles[1][b] == 0):
1910
+ # 1 / (sqrt(a1*s)*(a0*sqrt(s+b0)**3))
1911
+ # == 1/(sqrt(a1)*a0) * 1/(sqrt(s)*(sqrt(s+b0)**3))
1912
+ a_ = poles[0][b]
1913
+ k_ = constants/sqrt(poles[1][a])/poles[0][a]
1914
+ result = k_*(
1915
+ (2*a_**2*t+1)*t*exp(a_**2*t)*erfc(a_*sqrt(t)) -
1916
+ 2/sqrt(pi)*a_*t**(S(3)/2))
1917
+ _debug(' rule 5.3.15')
1918
+ elif (
1919
+ poles[0][n] == -1 and poles[0][m] == 1 and
1920
+ poles[1][n] == -S.Half and poles[1][m] == 1):
1921
+ # 1 / ( (a0*s+b0)* sqrt(a1*s+b1) )
1922
+ # == 1/(sqrt(a1)*a0) * 1 / ( (s+b0/a0)* sqrt(s+b1/a1) )
1923
+ a_ = poles[0][b]/poles[0][a]
1924
+ b_ = poles[1][b]/poles[1][a]
1925
+ k_ = constants/sqrt(poles[1][a])/poles[0][a]
1926
+ result = k_*(
1927
+ 1/sqrt(b_-a_)*exp(-a_*t)*erf(sqrt(b_-a_)*sqrt(t)))
1928
+ _debug(' rule 5.3.23')
1929
+
1930
+ elif len(poles) == 2 and len(zeros) == 1:
1931
+ if (
1932
+ poles[0][n] == -1 and poles[0][m] == 1 and
1933
+ poles[1][n] == -1 and poles[1][m] == S.Half and
1934
+ zeros[0][n] == S.Half and zeros[0][m] == 1 and
1935
+ zeros[0][b] == 0):
1936
+ # sqrt(za0*s)/((a0*s+b0)*(a1*sqrt(s)+b1))
1937
+ # == sqrt(za0)/(a0*a1) * s/((s+b0/a0)*(sqrt(s)+b1/a1))
1938
+ a_sq = poles[1][b]/poles[1][a]
1939
+ a_ = a_sq**2
1940
+ b_ = -poles[0][b]/poles[0][a]
1941
+ k_ = sqrt(zeros[0][a])/poles[0][a]/poles[1][a]/(a_-b_)*constants
1942
+ if a_sq.is_positive and b_.is_positive:
1943
+ result = k_*(
1944
+ a_*exp(a_*t)*erfc(sqrt(a_)*sqrt(t)) +
1945
+ sqrt(a_)*sqrt(b_)*exp(b_*t)*erfc(sqrt(b_)*sqrt(t)) -
1946
+ b_*exp(b_*t))
1947
+ _debug(' rule 5.3.6')
1948
+ elif (
1949
+ poles[0][n] == -1 and poles[0][m] == 1 and
1950
+ poles[0][b] == 0 and poles[1][n] == -1 and
1951
+ poles[1][m] == S.Half and zeros[0][n] == 1 and
1952
+ zeros[0][m] == S.Half):
1953
+ # (az*sqrt(s)+bz)/(a0*s*(a1*sqrt(s)+b1))
1954
+ # == az/a0/a1 * (sqrt(z)+bz/az)/(s*(sqrt(s)+b1/a1))
1955
+ a_num = zeros[0][b]/zeros[0][a]
1956
+ a_ = poles[1][b]/poles[1][a]
1957
+ if a_+a_num == 0:
1958
+ k_ = zeros[0][a]/poles[0][a]/poles[1][a]*constants
1959
+ result = k_*(
1960
+ 2*exp(a_**2*t)*erfc(a_*sqrt(t))-1)
1961
+ _debug(' rule 5.3.17')
1962
+ elif (
1963
+ poles[1][n] == -1 and poles[1][m] == 1 and
1964
+ poles[1][b] == 0 and poles[0][n] == -2 and
1965
+ poles[0][m] == S.Half and zeros[0][n] == 2 and
1966
+ zeros[0][m] == S.Half):
1967
+ # (az*sqrt(s)+bz)**2/(a1*s*(a0*sqrt(s)+b0)**2)
1968
+ # == az**2/a1/a0**2 * (sqrt(z)+bz/az)**2/(s*(sqrt(s)+b0/a0)**2)
1969
+ a_num = zeros[0][b]/zeros[0][a]
1970
+ a_ = poles[0][b]/poles[0][a]
1971
+ if a_+a_num == 0:
1972
+ k_ = zeros[0][a]**2/poles[1][a]/poles[0][a]**2*constants
1973
+ result = k_*(
1974
+ 1 + 8*a_**2*t*exp(a_**2*t)*erfc(a_*sqrt(t)) -
1975
+ 8/sqrt(pi)*a_*sqrt(t))
1976
+ _debug(' rule 5.3.18')
1977
+ elif (
1978
+ poles[1][n] == -1 and poles[1][m] == 1 and
1979
+ poles[1][b] == 0 and poles[0][n] == -3 and
1980
+ poles[0][m] == S.Half and zeros[0][n] == 3 and
1981
+ zeros[0][m] == S.Half):
1982
+ # (az*sqrt(s)+bz)**3/(a1*s*(a0*sqrt(s)+b0)**3)
1983
+ # == az**3/a1/a0**3 * (sqrt(z)+bz/az)**3/(s*(sqrt(s)+b0/a0)**3)
1984
+ a_num = zeros[0][b]/zeros[0][a]
1985
+ a_ = poles[0][b]/poles[0][a]
1986
+ if a_+a_num == 0:
1987
+ k_ = zeros[0][a]**3/poles[1][a]/poles[0][a]**3*constants
1988
+ result = k_*(
1989
+ 2*(8*a_**4*t**2+8*a_**2*t+1)*exp(a_**2*t) *
1990
+ erfc(a_*sqrt(t))-8/sqrt(pi)*a_*sqrt(t)*(2*a_**2*t+1)-1)
1991
+ _debug(' rule 5.3.19')
1992
+
1993
+ elif len(poles) == 3 and len(zeros) == 0:
1994
+ if (
1995
+ poles[0][n] == -1 and poles[0][b] == 0 and poles[0][m] == 1 and
1996
+ poles[1][n] == -1 and poles[1][m] == 1 and
1997
+ poles[2][n] == -S.Half and poles[2][m] == 1):
1998
+ # 1/((a0*s)*(a1*s+b1)*sqrt(a2*s))
1999
+ # == 1/(a0*a1*sqrt(a2)) * 1/((s)*(s+b1/a1)*sqrt(s))
2000
+ a_ = -poles[1][b]/poles[1][a]
2001
+ k_ = 1/poles[0][a]/poles[1][a]/sqrt(poles[2][a])*constants
2002
+ if a_.is_positive:
2003
+ result = k_ * (
2004
+ a_**(-S(3)/2) * exp(a_*t) * erf(sqrt(a_)*sqrt(t)) -
2005
+ 2/a_/sqrt(pi)*sqrt(t))
2006
+ _debug(' rule 5.3.2')
2007
+ elif (
2008
+ poles[0][n] == -1 and poles[0][m] == 1 and
2009
+ poles[1][n] == -1 and poles[1][m] == S.Half and
2010
+ poles[2][n] == -S.Half and poles[2][m] == 1 and
2011
+ poles[2][b] == 0):
2012
+ # 1/((a0*s+b0)*(a1*sqrt(s)+b1)*(sqrt(a2)*sqrt(s)))
2013
+ # == 1/(a0*a1*sqrt(a2)) * 1/((s+b0/a0)*(sqrt(s)+b1/a1)*sqrt(s))
2014
+ a_sq = poles[1][b]/poles[1][a]
2015
+ a_ = a_sq**2
2016
+ b_ = -poles[0][b]/poles[0][a]
2017
+ k_ = (
2018
+ 1/poles[0][a]/poles[1][a]/sqrt(poles[2][a]) /
2019
+ (sqrt(b_)*(a_-b_)))
2020
+ if a_sq.is_positive and b_.is_positive:
2021
+ result = k_ * (
2022
+ sqrt(b_)*exp(a_*t)*erfc(sqrt(a_)*sqrt(t)) +
2023
+ sqrt(a_)*exp(b_*t)*erf(sqrt(b_)*sqrt(t)) -
2024
+ sqrt(b_)*exp(b_*t))
2025
+ _debug(' rule 5.3.9')
2026
+
2027
+ if result is None:
2028
+ return None
2029
+ else:
2030
+ return Heaviside(t)*result, condition
2031
+
2032
+
2033
+ @DEBUG_WRAP
2034
+ def _inverse_laplace_early_prog_rules(F, s, t, plane):
2035
+ """
2036
+ Helper function for the class InverseLaplaceTransform.
2037
+ """
2038
+ prog_rules = [_inverse_laplace_irrational]
2039
+
2040
+ for p_rule in prog_rules:
2041
+ if (r := p_rule(F, s, t, plane)) is not None:
2042
+ return r
2043
+ return None
2044
+
2045
+
2046
+ @DEBUG_WRAP
2047
+ def _inverse_laplace_apply_prog_rules(F, s, t, plane):
2048
+ """
2049
+ Helper function for the class InverseLaplaceTransform.
2050
+ """
2051
+ prog_rules = [_inverse_laplace_time_shift, _inverse_laplace_freq_shift,
2052
+ _inverse_laplace_time_diff, _inverse_laplace_diff,
2053
+ _inverse_laplace_irrational]
2054
+
2055
+ for p_rule in prog_rules:
2056
+ if (r := p_rule(F, s, t, plane)) is not None:
2057
+ return r
2058
+ return None
2059
+
2060
+
2061
+ @DEBUG_WRAP
2062
+ def _inverse_laplace_expand(fn, s, t, plane):
2063
+ """
2064
+ Helper function for the class InverseLaplaceTransform.
2065
+ """
2066
+ if fn.is_Add:
2067
+ return None
2068
+ r = expand(fn, deep=False)
2069
+ if r.is_Add:
2070
+ return _inverse_laplace_transform(
2071
+ r, s, t, plane, simplify=False, dorational=True)
2072
+ r = expand_mul(fn)
2073
+ if r.is_Add:
2074
+ return _inverse_laplace_transform(
2075
+ r, s, t, plane, simplify=False, dorational=True)
2076
+ r = expand(fn)
2077
+ if r.is_Add:
2078
+ return _inverse_laplace_transform(
2079
+ r, s, t, plane, simplify=False, dorational=True)
2080
+ if fn.is_rational_function(s):
2081
+ r = fn.apart(s).doit()
2082
+ if r.is_Add:
2083
+ return _inverse_laplace_transform(
2084
+ r, s, t, plane, simplify=False, dorational=True)
2085
+ return None
2086
+
2087
+
2088
+ @DEBUG_WRAP
2089
+ def _inverse_laplace_rational(fn, s, t, plane, *, simplify):
2090
+ """
2091
+ Helper function for the class InverseLaplaceTransform.
2092
+ """
2093
+ x_ = symbols('x_')
2094
+ f = fn.apart(s)
2095
+ terms = Add.make_args(f)
2096
+ terms_t = []
2097
+ conditions = [S.true]
2098
+ for term in terms:
2099
+ [n, d] = term.as_numer_denom()
2100
+ dc = d.as_poly(s).all_coeffs()
2101
+ dc_lead = dc[0]
2102
+ dc = [x/dc_lead for x in dc]
2103
+ nc = [x/dc_lead for x in n.as_poly(s).all_coeffs()]
2104
+ if len(dc) == 1:
2105
+ N = len(nc)-1
2106
+ for c in enumerate(nc):
2107
+ r = c[1]*DiracDelta(t, N-c[0])
2108
+ terms_t.append(r)
2109
+ elif len(dc) == 2:
2110
+ r = nc[0]*exp(-dc[1]*t)
2111
+ terms_t.append(Heaviside(t)*r)
2112
+ elif len(dc) == 3:
2113
+ a = dc[1]/2
2114
+ b = (dc[2]-a**2).factor()
2115
+ if len(nc) == 1:
2116
+ nc = [S.Zero] + nc
2117
+ l, m = tuple(nc)
2118
+ if b == 0:
2119
+ r = (m*t+l*(1-a*t))*exp(-a*t)
2120
+ else:
2121
+ hyp = False
2122
+ if b.is_negative:
2123
+ b = -b
2124
+ hyp = True
2125
+ b2 = list(roots(x_**2-b, x_).keys())[0]
2126
+ bs = sqrt(b).simplify()
2127
+ if hyp:
2128
+ r = (
2129
+ l*exp(-a*t)*cosh(b2*t) + (m-a*l) /
2130
+ bs*exp(-a*t)*sinh(bs*t))
2131
+ else:
2132
+ r = l*exp(-a*t)*cos(b2*t) + (m-a*l)/bs*exp(-a*t)*sin(bs*t)
2133
+ terms_t.append(Heaviside(t)*r)
2134
+ else:
2135
+ ft, cond = _inverse_laplace_transform(
2136
+ term, s, t, plane, simplify=simplify, dorational=False)
2137
+ terms_t.append(ft)
2138
+ conditions.append(cond)
2139
+
2140
+ result = Add(*terms_t)
2141
+ if simplify:
2142
+ result = result.simplify(doit=False)
2143
+ return result, And(*conditions)
2144
+
2145
+
2146
+ @DEBUG_WRAP
2147
+ def _inverse_laplace_transform(fn, s_, t_, plane, *, simplify, dorational):
2148
+ """
2149
+ Front-end function of the inverse Laplace transform. It tries to apply all
2150
+ known rules recursively. If everything else fails, it tries to integrate.
2151
+ """
2152
+ terms = Add.make_args(fn)
2153
+ terms_t = []
2154
+ conditions = []
2155
+
2156
+ for term in terms:
2157
+ if term.has(exp):
2158
+ # Simplify expressions with exp() such that time-shifted
2159
+ # expressions have negative exponents in the numerator instead of
2160
+ # positive exponents in the numerator and denominator; this is a
2161
+ # (necessary) trick. It will, for example, convert
2162
+ # (s**2*exp(2*s) + 4*exp(s) - 4)*exp(-2*s)/(s*(s**2 + 1)) into
2163
+ # (s**2 + 4*exp(-s) - 4*exp(-2*s))/(s*(s**2 + 1))
2164
+ term = term.subs(s_, -s_).together().subs(s_, -s_)
2165
+ k, f = term.as_independent(s_, as_Add=False)
2166
+ if (
2167
+ dorational and term.is_rational_function(s_) and
2168
+ (r := _inverse_laplace_rational(
2169
+ f, s_, t_, plane, simplify=simplify))
2170
+ is not None or
2171
+ (r := _inverse_laplace_apply_simple_rules(f, s_, t_))
2172
+ is not None or
2173
+ (r := _inverse_laplace_early_prog_rules(f, s_, t_, plane))
2174
+ is not None or
2175
+ (r := _inverse_laplace_expand(f, s_, t_, plane))
2176
+ is not None or
2177
+ (r := _inverse_laplace_apply_prog_rules(f, s_, t_, plane))
2178
+ is not None):
2179
+ pass
2180
+ elif any(undef.has(s_) for undef in f.atoms(AppliedUndef)):
2181
+ # If there are undefined functions f(t) then integration is
2182
+ # unlikely to do anything useful so we skip it and given an
2183
+ # unevaluated LaplaceTransform.
2184
+ r = (InverseLaplaceTransform(f, s_, t_, plane), S.true)
2185
+ elif (
2186
+ r := _inverse_laplace_transform_integration(
2187
+ f, s_, t_, plane, simplify=simplify)) is not None:
2188
+ pass
2189
+ else:
2190
+ r = (InverseLaplaceTransform(f, s_, t_, plane), S.true)
2191
+ (ri_, ci_) = r
2192
+ terms_t.append(k*ri_)
2193
+ conditions.append(ci_)
2194
+
2195
+ result = Add(*terms_t)
2196
+ if simplify:
2197
+ result = result.simplify(doit=False)
2198
+ condition = And(*conditions)
2199
+
2200
+ return result, condition
2201
+
2202
+
2203
+ class InverseLaplaceTransform(IntegralTransform):
2204
+ """
2205
+ Class representing unevaluated inverse Laplace transforms.
2206
+
2207
+ For usage of this class, see the :class:`IntegralTransform` docstring.
2208
+
2209
+ For how to compute inverse Laplace transforms, see the
2210
+ :func:`inverse_laplace_transform` docstring.
2211
+ """
2212
+
2213
+ _name = 'Inverse Laplace'
2214
+ _none_sentinel = Dummy('None')
2215
+ _c = Dummy('c')
2216
+
2217
+ def __new__(cls, F, s, x, plane, **opts):
2218
+ if plane is None:
2219
+ plane = InverseLaplaceTransform._none_sentinel
2220
+ return IntegralTransform.__new__(cls, F, s, x, plane, **opts)
2221
+
2222
+ @property
2223
+ def fundamental_plane(self):
2224
+ plane = self.args[3]
2225
+ if plane is InverseLaplaceTransform._none_sentinel:
2226
+ plane = None
2227
+ return plane
2228
+
2229
+ def _compute_transform(self, F, s, t, **hints):
2230
+ return _inverse_laplace_transform_integration(
2231
+ F, s, t, self.fundamental_plane, **hints)
2232
+
2233
+ def _as_integral(self, F, s, t):
2234
+ c = self.__class__._c
2235
+ return (
2236
+ Integral(exp(s*t)*F, (s, c - S.ImaginaryUnit*S.Infinity,
2237
+ c + S.ImaginaryUnit*S.Infinity)) /
2238
+ (2*S.Pi*S.ImaginaryUnit))
2239
+
2240
+ def doit(self, **hints):
2241
+ """
2242
+ Try to evaluate the transform in closed form.
2243
+
2244
+ Explanation
2245
+ ===========
2246
+
2247
+ Standard hints are the following:
2248
+ - ``noconds``: if True, do not return convergence conditions. The
2249
+ default setting is `True`.
2250
+ - ``simplify``: if True, it simplifies the final result. The
2251
+ default setting is `False`.
2252
+ """
2253
+ _noconds = hints.get('noconds', True)
2254
+ _simplify = hints.get('simplify', False)
2255
+
2256
+ debugf('[ILT doit] (%s, %s, %s)', (self.function,
2257
+ self.function_variable,
2258
+ self.transform_variable))
2259
+
2260
+ s_ = self.function_variable
2261
+ t_ = self.transform_variable
2262
+ fn = self.function
2263
+ plane = self.fundamental_plane
2264
+
2265
+ r = _inverse_laplace_transform(
2266
+ fn, s_, t_, plane, simplify=_simplify, dorational=True)
2267
+
2268
+ if _noconds:
2269
+ return r[0]
2270
+ else:
2271
+ return r
2272
+
2273
+
2274
+ def inverse_laplace_transform(F, s, t, plane=None, **hints):
2275
+ r"""
2276
+ Compute the inverse Laplace transform of `F(s)`, defined as
2277
+
2278
+ .. math ::
2279
+ f(t) = \frac{1}{2\pi i} \int_{c-i\infty}^{c+i\infty} e^{st}
2280
+ F(s) \mathrm{d}s,
2281
+
2282
+ for `c` so large that `F(s)` has no singularites in the
2283
+ half-plane `\operatorname{Re}(s) > c-\epsilon`.
2284
+
2285
+ Explanation
2286
+ ===========
2287
+
2288
+ The plane can be specified by
2289
+ argument ``plane``, but will be inferred if passed as None.
2290
+
2291
+ Under certain regularity conditions, this recovers `f(t)` from its
2292
+ Laplace Transform `F(s)`, for non-negative `t`, and vice
2293
+ versa.
2294
+
2295
+ If the integral cannot be computed in closed form, this function returns
2296
+ an unevaluated :class:`InverseLaplaceTransform` object.
2297
+
2298
+ Note that this function will always assume `t` to be real,
2299
+ regardless of the SymPy assumption on `t`.
2300
+
2301
+ For a description of possible hints, refer to the docstring of
2302
+ :func:`sympy.integrals.transforms.IntegralTransform.doit`.
2303
+
2304
+ Examples
2305
+ ========
2306
+
2307
+ >>> from sympy import inverse_laplace_transform, exp, Symbol
2308
+ >>> from sympy.abc import s, t
2309
+ >>> a = Symbol('a', positive=True)
2310
+ >>> inverse_laplace_transform(exp(-a*s)/s, s, t)
2311
+ Heaviside(-a + t)
2312
+
2313
+ See Also
2314
+ ========
2315
+
2316
+ laplace_transform
2317
+ hankel_transform, inverse_hankel_transform
2318
+ """
2319
+ _noconds = hints.get('noconds', True)
2320
+ _simplify = hints.get('simplify', False)
2321
+
2322
+ if isinstance(F, MatrixBase) and hasattr(F, 'applyfunc'):
2323
+ return F.applyfunc(
2324
+ lambda Fij: inverse_laplace_transform(Fij, s, t, plane, **hints))
2325
+
2326
+ r, c = InverseLaplaceTransform(F, s, t, plane).doit(
2327
+ noconds=False, simplify=_simplify)
2328
+
2329
+ if _noconds:
2330
+ return r
2331
+ else:
2332
+ return r, c
2333
+
2334
+
2335
+ def _fast_inverse_laplace(e, s, t):
2336
+ """Fast inverse Laplace transform of rational function including RootSum"""
2337
+ a, b, n = symbols('a, b, n', cls=Wild, exclude=[s])
2338
+
2339
+ def _ilt(e):
2340
+ if not e.has(s):
2341
+ return e
2342
+ elif e.is_Add:
2343
+ return _ilt_add(e)
2344
+ elif e.is_Mul:
2345
+ return _ilt_mul(e)
2346
+ elif e.is_Pow:
2347
+ return _ilt_pow(e)
2348
+ elif isinstance(e, RootSum):
2349
+ return _ilt_rootsum(e)
2350
+ else:
2351
+ raise NotImplementedError
2352
+
2353
+ def _ilt_add(e):
2354
+ return e.func(*map(_ilt, e.args))
2355
+
2356
+ def _ilt_mul(e):
2357
+ coeff, expr = e.as_independent(s)
2358
+ if expr.is_Mul:
2359
+ raise NotImplementedError
2360
+ return coeff * _ilt(expr)
2361
+
2362
+ def _ilt_pow(e):
2363
+ match = e.match((a*s + b)**n)
2364
+ if match is not None:
2365
+ nm, am, bm = match[n], match[a], match[b]
2366
+ if nm.is_Integer and nm < 0:
2367
+ return t**(-nm-1)*exp(-(bm/am)*t)/(am**-nm*gamma(-nm))
2368
+ if nm == 1:
2369
+ return exp(-(bm/am)*t) / am
2370
+ raise NotImplementedError
2371
+
2372
+ def _ilt_rootsum(e):
2373
+ expr = e.fun.expr
2374
+ [variable] = e.fun.variables
2375
+ return RootSum(e.poly, Lambda(variable, together(_ilt(expr))))
2376
+
2377
+ return _ilt(e)
.venv/lib/python3.12/site-packages/sympy/integrals/manualintegrate.py ADDED
@@ -0,0 +1,2174 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ """Integration method that emulates by-hand techniques.
2
+
3
+ This module also provides functionality to get the steps used to evaluate a
4
+ particular integral, in the ``integral_steps`` function. This will return
5
+ nested ``Rule`` s representing the integration rules used.
6
+
7
+ Each ``Rule`` class represents a (maybe parametrized) integration rule, e.g.
8
+ ``SinRule`` for integrating ``sin(x)`` and ``ReciprocalSqrtQuadraticRule``
9
+ for integrating ``1/sqrt(a+b*x+c*x**2)``. The ``eval`` method returns the
10
+ integration result.
11
+
12
+ The ``manualintegrate`` function computes the integral by calling ``eval``
13
+ on the rule returned by ``integral_steps``.
14
+
15
+ The integrator can be extended with new heuristics and evaluation
16
+ techniques. To do so, extend the ``Rule`` class, implement ``eval`` method,
17
+ then write a function that accepts an ``IntegralInfo`` object and returns
18
+ either a ``Rule`` instance or ``None``. If the new technique requires a new
19
+ match, add the key and call to the antiderivative function to integral_steps.
20
+ To enable simple substitutions, add the match to find_substitutions.
21
+
22
+ """
23
+
24
+ from __future__ import annotations
25
+ from typing import NamedTuple, Type, Callable, Sequence
26
+ from abc import ABC, abstractmethod
27
+ from dataclasses import dataclass
28
+ from collections import defaultdict
29
+ from collections.abc import Mapping
30
+
31
+ from sympy.core.add import Add
32
+ from sympy.core.cache import cacheit
33
+ from sympy.core.containers import Dict
34
+ from sympy.core.expr import Expr
35
+ from sympy.core.function import Derivative
36
+ from sympy.core.logic import fuzzy_not
37
+ from sympy.core.mul import Mul
38
+ from sympy.core.numbers import Integer, Number, E
39
+ from sympy.core.power import Pow
40
+ from sympy.core.relational import Eq, Ne, Boolean
41
+ from sympy.core.singleton import S
42
+ from sympy.core.symbol import Dummy, Symbol, Wild
43
+ from sympy.functions.elementary.complexes import Abs
44
+ from sympy.functions.elementary.exponential import exp, log
45
+ from sympy.functions.elementary.hyperbolic import (HyperbolicFunction, csch,
46
+ cosh, coth, sech, sinh, tanh, asinh)
47
+ from sympy.functions.elementary.miscellaneous import sqrt
48
+ from sympy.functions.elementary.piecewise import Piecewise
49
+ from sympy.functions.elementary.trigonometric import (TrigonometricFunction,
50
+ cos, sin, tan, cot, csc, sec, acos, asin, atan, acot, acsc, asec)
51
+ from sympy.functions.special.delta_functions import Heaviside, DiracDelta
52
+ from sympy.functions.special.error_functions import (erf, erfi, fresnelc,
53
+ fresnels, Ci, Chi, Si, Shi, Ei, li)
54
+ from sympy.functions.special.gamma_functions import uppergamma
55
+ from sympy.functions.special.elliptic_integrals import elliptic_e, elliptic_f
56
+ from sympy.functions.special.polynomials import (chebyshevt, chebyshevu,
57
+ legendre, hermite, laguerre, assoc_laguerre, gegenbauer, jacobi,
58
+ OrthogonalPolynomial)
59
+ from sympy.functions.special.zeta_functions import polylog
60
+ from .integrals import Integral
61
+ from sympy.logic.boolalg import And
62
+ from sympy.ntheory.factor_ import primefactors
63
+ from sympy.polys.polytools import degree, lcm_list, gcd_list, Poly
64
+ from sympy.simplify.radsimp import fraction
65
+ from sympy.simplify.simplify import simplify
66
+ from sympy.solvers.solvers import solve
67
+ from sympy.strategies.core import switch, do_one, null_safe, condition
68
+ from sympy.utilities.iterables import iterable
69
+ from sympy.utilities.misc import debug
70
+
71
+
72
+ @dataclass
73
+ class Rule(ABC):
74
+ integrand: Expr
75
+ variable: Symbol
76
+
77
+ @abstractmethod
78
+ def eval(self) -> Expr:
79
+ pass
80
+
81
+ @abstractmethod
82
+ def contains_dont_know(self) -> bool:
83
+ pass
84
+
85
+
86
+ @dataclass
87
+ class AtomicRule(Rule, ABC):
88
+ """A simple rule that does not depend on other rules"""
89
+ def contains_dont_know(self) -> bool:
90
+ return False
91
+
92
+
93
+ @dataclass
94
+ class ConstantRule(AtomicRule):
95
+ """integrate(a, x) -> a*x"""
96
+ def eval(self) -> Expr:
97
+ return self.integrand * self.variable
98
+
99
+
100
+ @dataclass
101
+ class ConstantTimesRule(Rule):
102
+ """integrate(a*f(x), x) -> a*integrate(f(x), x)"""
103
+ constant: Expr
104
+ other: Expr
105
+ substep: Rule
106
+
107
+ def eval(self) -> Expr:
108
+ return self.constant * self.substep.eval()
109
+
110
+ def contains_dont_know(self) -> bool:
111
+ return self.substep.contains_dont_know()
112
+
113
+
114
+ @dataclass
115
+ class PowerRule(AtomicRule):
116
+ """integrate(x**a, x)"""
117
+ base: Expr
118
+ exp: Expr
119
+
120
+ def eval(self) -> Expr:
121
+ return Piecewise(
122
+ ((self.base**(self.exp + 1))/(self.exp + 1), Ne(self.exp, -1)),
123
+ (log(self.base), True),
124
+ )
125
+
126
+
127
+ @dataclass
128
+ class NestedPowRule(AtomicRule):
129
+ """integrate((x**a)**b, x)"""
130
+ base: Expr
131
+ exp: Expr
132
+
133
+ def eval(self) -> Expr:
134
+ m = self.base * self.integrand
135
+ return Piecewise((m / (self.exp + 1), Ne(self.exp, -1)),
136
+ (m * log(self.base), True))
137
+
138
+
139
+ @dataclass
140
+ class AddRule(Rule):
141
+ """integrate(f(x) + g(x), x) -> integrate(f(x), x) + integrate(g(x), x)"""
142
+ substeps: list[Rule]
143
+
144
+ def eval(self) -> Expr:
145
+ return Add(*(substep.eval() for substep in self.substeps))
146
+
147
+ def contains_dont_know(self) -> bool:
148
+ return any(substep.contains_dont_know() for substep in self.substeps)
149
+
150
+
151
+ @dataclass
152
+ class URule(Rule):
153
+ """integrate(f(g(x))*g'(x), x) -> integrate(f(u), u), u = g(x)"""
154
+ u_var: Symbol
155
+ u_func: Expr
156
+ substep: Rule
157
+
158
+ def eval(self) -> Expr:
159
+ result = self.substep.eval()
160
+ if self.u_func.is_Pow:
161
+ base, exp_ = self.u_func.as_base_exp()
162
+ if exp_ == -1:
163
+ # avoid needless -log(1/x) from substitution
164
+ result = result.subs(log(self.u_var), -log(base))
165
+ return result.subs(self.u_var, self.u_func)
166
+
167
+ def contains_dont_know(self) -> bool:
168
+ return self.substep.contains_dont_know()
169
+
170
+
171
+ @dataclass
172
+ class PartsRule(Rule):
173
+ """integrate(u(x)*v'(x), x) -> u(x)*v(x) - integrate(u'(x)*v(x), x)"""
174
+ u: Symbol
175
+ dv: Expr
176
+ v_step: Rule
177
+ second_step: Rule | None # None when is a substep of CyclicPartsRule
178
+
179
+ def eval(self) -> Expr:
180
+ assert self.second_step is not None
181
+ v = self.v_step.eval()
182
+ return self.u * v - self.second_step.eval()
183
+
184
+ def contains_dont_know(self) -> bool:
185
+ return self.v_step.contains_dont_know() or (
186
+ self.second_step is not None and self.second_step.contains_dont_know())
187
+
188
+
189
+ @dataclass
190
+ class CyclicPartsRule(Rule):
191
+ """Apply PartsRule multiple times to integrate exp(x)*sin(x)"""
192
+ parts_rules: list[PartsRule]
193
+ coefficient: Expr
194
+
195
+ def eval(self) -> Expr:
196
+ result = []
197
+ sign = 1
198
+ for rule in self.parts_rules:
199
+ result.append(sign * rule.u * rule.v_step.eval())
200
+ sign *= -1
201
+ return Add(*result) / (1 - self.coefficient)
202
+
203
+ def contains_dont_know(self) -> bool:
204
+ return any(substep.contains_dont_know() for substep in self.parts_rules)
205
+
206
+
207
+ @dataclass
208
+ class TrigRule(AtomicRule, ABC):
209
+ pass
210
+
211
+
212
+ @dataclass
213
+ class SinRule(TrigRule):
214
+ """integrate(sin(x), x) -> -cos(x)"""
215
+ def eval(self) -> Expr:
216
+ return -cos(self.variable)
217
+
218
+
219
+ @dataclass
220
+ class CosRule(TrigRule):
221
+ """integrate(cos(x), x) -> sin(x)"""
222
+ def eval(self) -> Expr:
223
+ return sin(self.variable)
224
+
225
+
226
+ @dataclass
227
+ class SecTanRule(TrigRule):
228
+ """integrate(sec(x)*tan(x), x) -> sec(x)"""
229
+ def eval(self) -> Expr:
230
+ return sec(self.variable)
231
+
232
+
233
+ @dataclass
234
+ class CscCotRule(TrigRule):
235
+ """integrate(csc(x)*cot(x), x) -> -csc(x)"""
236
+ def eval(self) -> Expr:
237
+ return -csc(self.variable)
238
+
239
+
240
+ @dataclass
241
+ class Sec2Rule(TrigRule):
242
+ """integrate(sec(x)**2, x) -> tan(x)"""
243
+ def eval(self) -> Expr:
244
+ return tan(self.variable)
245
+
246
+
247
+ @dataclass
248
+ class Csc2Rule(TrigRule):
249
+ """integrate(csc(x)**2, x) -> -cot(x)"""
250
+ def eval(self) -> Expr:
251
+ return -cot(self.variable)
252
+
253
+
254
+ @dataclass
255
+ class HyperbolicRule(AtomicRule, ABC):
256
+ pass
257
+
258
+
259
+ @dataclass
260
+ class SinhRule(HyperbolicRule):
261
+ """integrate(sinh(x), x) -> cosh(x)"""
262
+ def eval(self) -> Expr:
263
+ return cosh(self.variable)
264
+
265
+
266
+ @dataclass
267
+ class CoshRule(HyperbolicRule):
268
+ """integrate(cosh(x), x) -> sinh(x)"""
269
+ def eval(self):
270
+ return sinh(self.variable)
271
+
272
+
273
+ @dataclass
274
+ class ExpRule(AtomicRule):
275
+ """integrate(a**x, x) -> a**x/ln(a)"""
276
+ base: Expr
277
+ exp: Expr
278
+
279
+ def eval(self) -> Expr:
280
+ return self.integrand / log(self.base)
281
+
282
+
283
+ @dataclass
284
+ class ReciprocalRule(AtomicRule):
285
+ """integrate(1/x, x) -> ln(x)"""
286
+ base: Expr
287
+
288
+ def eval(self) -> Expr:
289
+ return log(self.base)
290
+
291
+
292
+ @dataclass
293
+ class ArcsinRule(AtomicRule):
294
+ """integrate(1/sqrt(1-x**2), x) -> asin(x)"""
295
+ def eval(self) -> Expr:
296
+ return asin(self.variable)
297
+
298
+
299
+ @dataclass
300
+ class ArcsinhRule(AtomicRule):
301
+ """integrate(1/sqrt(1+x**2), x) -> asin(x)"""
302
+ def eval(self) -> Expr:
303
+ return asinh(self.variable)
304
+
305
+
306
+ @dataclass
307
+ class ReciprocalSqrtQuadraticRule(AtomicRule):
308
+ """integrate(1/sqrt(a+b*x+c*x**2), x) -> log(2*sqrt(c)*sqrt(a+b*x+c*x**2)+b+2*c*x)/sqrt(c)"""
309
+ a: Expr
310
+ b: Expr
311
+ c: Expr
312
+
313
+ def eval(self) -> Expr:
314
+ a, b, c, x = self.a, self.b, self.c, self.variable
315
+ return log(2*sqrt(c)*sqrt(a+b*x+c*x**2)+b+2*c*x)/sqrt(c)
316
+
317
+
318
+ @dataclass
319
+ class SqrtQuadraticDenomRule(AtomicRule):
320
+ """integrate(poly(x)/sqrt(a+b*x+c*x**2), x)"""
321
+ a: Expr
322
+ b: Expr
323
+ c: Expr
324
+ coeffs: list[Expr]
325
+
326
+ def eval(self) -> Expr:
327
+ a, b, c, coeffs, x = self.a, self.b, self.c, self.coeffs.copy(), self.variable
328
+ # Integrate poly/sqrt(a+b*x+c*x**2) using recursion.
329
+ # coeffs are coefficients of the polynomial.
330
+ # Let I_n = x**n/sqrt(a+b*x+c*x**2), then
331
+ # I_n = A * x**(n-1)*sqrt(a+b*x+c*x**2) - B * I_{n-1} - C * I_{n-2}
332
+ # where A = 1/(n*c), B = (2*n-1)*b/(2*n*c), C = (n-1)*a/(n*c)
333
+ # See https://github.com/sympy/sympy/pull/23608 for proof.
334
+ result_coeffs = []
335
+ coeffs = coeffs.copy()
336
+ for i in range(len(coeffs)-2):
337
+ n = len(coeffs)-1-i
338
+ coeff = coeffs[i]/(c*n)
339
+ result_coeffs.append(coeff)
340
+ coeffs[i+1] -= (2*n-1)*b/2*coeff
341
+ coeffs[i+2] -= (n-1)*a*coeff
342
+ d, e = coeffs[-1], coeffs[-2]
343
+ s = sqrt(a+b*x+c*x**2)
344
+ constant = d-b*e/(2*c)
345
+ if constant == 0:
346
+ I0 = 0
347
+ else:
348
+ step = inverse_trig_rule(IntegralInfo(1/s, x), degenerate=False)
349
+ I0 = constant*step.eval()
350
+ return Add(*(result_coeffs[i]*x**(len(coeffs)-2-i)
351
+ for i in range(len(result_coeffs))), e/c)*s + I0
352
+
353
+
354
+ @dataclass
355
+ class SqrtQuadraticRule(AtomicRule):
356
+ """integrate(sqrt(a+b*x+c*x**2), x)"""
357
+ a: Expr
358
+ b: Expr
359
+ c: Expr
360
+
361
+ def eval(self) -> Expr:
362
+ step = sqrt_quadratic_rule(IntegralInfo(self.integrand, self.variable), degenerate=False)
363
+ return step.eval()
364
+
365
+
366
+ @dataclass
367
+ class AlternativeRule(Rule):
368
+ """Multiple ways to do integration."""
369
+ alternatives: list[Rule]
370
+
371
+ def eval(self) -> Expr:
372
+ return self.alternatives[0].eval()
373
+
374
+ def contains_dont_know(self) -> bool:
375
+ return any(substep.contains_dont_know() for substep in self.alternatives)
376
+
377
+
378
+ @dataclass
379
+ class DontKnowRule(Rule):
380
+ """Leave the integral as is."""
381
+ def eval(self) -> Expr:
382
+ return Integral(self.integrand, self.variable)
383
+
384
+ def contains_dont_know(self) -> bool:
385
+ return True
386
+
387
+
388
+ @dataclass
389
+ class DerivativeRule(AtomicRule):
390
+ """integrate(f'(x), x) -> f(x)"""
391
+ def eval(self) -> Expr:
392
+ assert isinstance(self.integrand, Derivative)
393
+ variable_count = list(self.integrand.variable_count)
394
+ for i, (var, count) in enumerate(variable_count):
395
+ if var == self.variable:
396
+ variable_count[i] = (var, count - 1)
397
+ break
398
+ return Derivative(self.integrand.expr, *variable_count)
399
+
400
+
401
+ @dataclass
402
+ class RewriteRule(Rule):
403
+ """Rewrite integrand to another form that is easier to handle."""
404
+ rewritten: Expr
405
+ substep: Rule
406
+
407
+ def eval(self) -> Expr:
408
+ return self.substep.eval()
409
+
410
+ def contains_dont_know(self) -> bool:
411
+ return self.substep.contains_dont_know()
412
+
413
+
414
+ @dataclass
415
+ class CompleteSquareRule(RewriteRule):
416
+ """Rewrite a+b*x+c*x**2 to a-b**2/(4*c) + c*(x+b/(2*c))**2"""
417
+ pass
418
+
419
+
420
+ @dataclass
421
+ class PiecewiseRule(Rule):
422
+ subfunctions: Sequence[tuple[Rule, bool | Boolean]]
423
+
424
+ def eval(self) -> Expr:
425
+ return Piecewise(*[(substep.eval(), cond)
426
+ for substep, cond in self.subfunctions])
427
+
428
+ def contains_dont_know(self) -> bool:
429
+ return any(substep.contains_dont_know() for substep, _ in self.subfunctions)
430
+
431
+
432
+ @dataclass
433
+ class HeavisideRule(Rule):
434
+ harg: Expr
435
+ ibnd: Expr
436
+ substep: Rule
437
+
438
+ def eval(self) -> Expr:
439
+ # If we are integrating over x and the integrand has the form
440
+ # Heaviside(m*x+b)*g(x) == Heaviside(harg)*g(symbol)
441
+ # then there needs to be continuity at -b/m == ibnd,
442
+ # so we subtract the appropriate term.
443
+ result = self.substep.eval()
444
+ return Heaviside(self.harg) * (result - result.subs(self.variable, self.ibnd))
445
+
446
+ def contains_dont_know(self) -> bool:
447
+ return self.substep.contains_dont_know()
448
+
449
+
450
+ @dataclass
451
+ class DiracDeltaRule(AtomicRule):
452
+ n: Expr
453
+ a: Expr
454
+ b: Expr
455
+
456
+ def eval(self) -> Expr:
457
+ n, a, b, x = self.n, self.a, self.b, self.variable
458
+ if n == 0:
459
+ return Heaviside(a+b*x)/b
460
+ return DiracDelta(a+b*x, n-1)/b
461
+
462
+
463
+ @dataclass
464
+ class TrigSubstitutionRule(Rule):
465
+ theta: Expr
466
+ func: Expr
467
+ rewritten: Expr
468
+ substep: Rule
469
+ restriction: bool | Boolean
470
+
471
+ def eval(self) -> Expr:
472
+ theta, func, x = self.theta, self.func, self.variable
473
+ func = func.subs(sec(theta), 1/cos(theta))
474
+ func = func.subs(csc(theta), 1/sin(theta))
475
+ func = func.subs(cot(theta), 1/tan(theta))
476
+
477
+ trig_function = list(func.find(TrigonometricFunction))
478
+ assert len(trig_function) == 1
479
+ trig_function = trig_function[0]
480
+ relation = solve(x - func, trig_function)
481
+ assert len(relation) == 1
482
+ numer, denom = fraction(relation[0])
483
+
484
+ if isinstance(trig_function, sin):
485
+ opposite = numer
486
+ hypotenuse = denom
487
+ adjacent = sqrt(denom**2 - numer**2)
488
+ inverse = asin(relation[0])
489
+ elif isinstance(trig_function, cos):
490
+ adjacent = numer
491
+ hypotenuse = denom
492
+ opposite = sqrt(denom**2 - numer**2)
493
+ inverse = acos(relation[0])
494
+ else: # tan
495
+ opposite = numer
496
+ adjacent = denom
497
+ hypotenuse = sqrt(denom**2 + numer**2)
498
+ inverse = atan(relation[0])
499
+
500
+ substitution = [
501
+ (sin(theta), opposite/hypotenuse),
502
+ (cos(theta), adjacent/hypotenuse),
503
+ (tan(theta), opposite/adjacent),
504
+ (theta, inverse)
505
+ ]
506
+ return Piecewise(
507
+ (self.substep.eval().subs(substitution).trigsimp(), self.restriction) # type: ignore
508
+ )
509
+
510
+ def contains_dont_know(self) -> bool:
511
+ return self.substep.contains_dont_know()
512
+
513
+
514
+ @dataclass
515
+ class ArctanRule(AtomicRule):
516
+ """integrate(a/(b*x**2+c), x) -> a/b / sqrt(c/b) * atan(x/sqrt(c/b))"""
517
+ a: Expr
518
+ b: Expr
519
+ c: Expr
520
+
521
+ def eval(self) -> Expr:
522
+ a, b, c, x = self.a, self.b, self.c, self.variable
523
+ return a/b / sqrt(c/b) * atan(x/sqrt(c/b))
524
+
525
+
526
+ @dataclass
527
+ class OrthogonalPolyRule(AtomicRule, ABC):
528
+ n: Expr
529
+
530
+
531
+ @dataclass
532
+ class JacobiRule(OrthogonalPolyRule):
533
+ a: Expr
534
+ b: Expr
535
+
536
+ def eval(self) -> Expr:
537
+ n, a, b, x = self.n, self.a, self.b, self.variable
538
+ return Piecewise(
539
+ (2*jacobi(n + 1, a - 1, b - 1, x)/(n + a + b), Ne(n + a + b, 0)),
540
+ (x, Eq(n, 0)),
541
+ ((a + b + 2)*x**2/4 + (a - b)*x/2, Eq(n, 1)))
542
+
543
+
544
+ @dataclass
545
+ class GegenbauerRule(OrthogonalPolyRule):
546
+ a: Expr
547
+
548
+ def eval(self) -> Expr:
549
+ n, a, x = self.n, self.a, self.variable
550
+ return Piecewise(
551
+ (gegenbauer(n + 1, a - 1, x)/(2*(a - 1)), Ne(a, 1)),
552
+ (chebyshevt(n + 1, x)/(n + 1), Ne(n, -1)),
553
+ (S.Zero, True))
554
+
555
+
556
+ @dataclass
557
+ class ChebyshevTRule(OrthogonalPolyRule):
558
+ def eval(self) -> Expr:
559
+ n, x = self.n, self.variable
560
+ return Piecewise(
561
+ ((chebyshevt(n + 1, x)/(n + 1) -
562
+ chebyshevt(n - 1, x)/(n - 1))/2, Ne(Abs(n), 1)),
563
+ (x**2/2, True))
564
+
565
+
566
+ @dataclass
567
+ class ChebyshevURule(OrthogonalPolyRule):
568
+ def eval(self) -> Expr:
569
+ n, x = self.n, self.variable
570
+ return Piecewise(
571
+ (chebyshevt(n + 1, x)/(n + 1), Ne(n, -1)),
572
+ (S.Zero, True))
573
+
574
+
575
+ @dataclass
576
+ class LegendreRule(OrthogonalPolyRule):
577
+ def eval(self) -> Expr:
578
+ n, x = self.n, self.variable
579
+ return(legendre(n + 1, x) - legendre(n - 1, x))/(2*n + 1)
580
+
581
+
582
+ @dataclass
583
+ class HermiteRule(OrthogonalPolyRule):
584
+ def eval(self) -> Expr:
585
+ n, x = self.n, self.variable
586
+ return hermite(n + 1, x)/(2*(n + 1))
587
+
588
+
589
+ @dataclass
590
+ class LaguerreRule(OrthogonalPolyRule):
591
+ def eval(self) -> Expr:
592
+ n, x = self.n, self.variable
593
+ return laguerre(n, x) - laguerre(n + 1, x)
594
+
595
+
596
+ @dataclass
597
+ class AssocLaguerreRule(OrthogonalPolyRule):
598
+ a: Expr
599
+
600
+ def eval(self) -> Expr:
601
+ return -assoc_laguerre(self.n + 1, self.a - 1, self.variable)
602
+
603
+
604
+ @dataclass
605
+ class IRule(AtomicRule, ABC):
606
+ a: Expr
607
+ b: Expr
608
+
609
+
610
+ @dataclass
611
+ class CiRule(IRule):
612
+ def eval(self) -> Expr:
613
+ a, b, x = self.a, self.b, self.variable
614
+ return cos(b)*Ci(a*x) - sin(b)*Si(a*x)
615
+
616
+
617
+ @dataclass
618
+ class ChiRule(IRule):
619
+ def eval(self) -> Expr:
620
+ a, b, x = self.a, self.b, self.variable
621
+ return cosh(b)*Chi(a*x) + sinh(b)*Shi(a*x)
622
+
623
+
624
+ @dataclass
625
+ class EiRule(IRule):
626
+ def eval(self) -> Expr:
627
+ a, b, x = self.a, self.b, self.variable
628
+ return exp(b)*Ei(a*x)
629
+
630
+
631
+ @dataclass
632
+ class SiRule(IRule):
633
+ def eval(self) -> Expr:
634
+ a, b, x = self.a, self.b, self.variable
635
+ return sin(b)*Ci(a*x) + cos(b)*Si(a*x)
636
+
637
+
638
+ @dataclass
639
+ class ShiRule(IRule):
640
+ def eval(self) -> Expr:
641
+ a, b, x = self.a, self.b, self.variable
642
+ return sinh(b)*Chi(a*x) + cosh(b)*Shi(a*x)
643
+
644
+
645
+ @dataclass
646
+ class LiRule(IRule):
647
+ def eval(self) -> Expr:
648
+ a, b, x = self.a, self.b, self.variable
649
+ return li(a*x + b)/a
650
+
651
+
652
+ @dataclass
653
+ class ErfRule(AtomicRule):
654
+ a: Expr
655
+ b: Expr
656
+ c: Expr
657
+
658
+ def eval(self) -> Expr:
659
+ a, b, c, x = self.a, self.b, self.c, self.variable
660
+ if a.is_extended_real:
661
+ return Piecewise(
662
+ (sqrt(S.Pi)/sqrt(-a)/2 * exp(c - b**2/(4*a)) *
663
+ erf((-2*a*x - b)/(2*sqrt(-a))), a < 0),
664
+ (sqrt(S.Pi)/sqrt(a)/2 * exp(c - b**2/(4*a)) *
665
+ erfi((2*a*x + b)/(2*sqrt(a))), True))
666
+ return sqrt(S.Pi)/sqrt(a)/2 * exp(c - b**2/(4*a)) * \
667
+ erfi((2*a*x + b)/(2*sqrt(a)))
668
+
669
+
670
+ @dataclass
671
+ class FresnelCRule(AtomicRule):
672
+ a: Expr
673
+ b: Expr
674
+ c: Expr
675
+
676
+ def eval(self) -> Expr:
677
+ a, b, c, x = self.a, self.b, self.c, self.variable
678
+ return sqrt(S.Pi)/sqrt(2*a) * (
679
+ cos(b**2/(4*a) - c)*fresnelc((2*a*x + b)/sqrt(2*a*S.Pi)) +
680
+ sin(b**2/(4*a) - c)*fresnels((2*a*x + b)/sqrt(2*a*S.Pi)))
681
+
682
+
683
+ @dataclass
684
+ class FresnelSRule(AtomicRule):
685
+ a: Expr
686
+ b: Expr
687
+ c: Expr
688
+
689
+ def eval(self) -> Expr:
690
+ a, b, c, x = self.a, self.b, self.c, self.variable
691
+ return sqrt(S.Pi)/sqrt(2*a) * (
692
+ cos(b**2/(4*a) - c)*fresnels((2*a*x + b)/sqrt(2*a*S.Pi)) -
693
+ sin(b**2/(4*a) - c)*fresnelc((2*a*x + b)/sqrt(2*a*S.Pi)))
694
+
695
+
696
+ @dataclass
697
+ class PolylogRule(AtomicRule):
698
+ a: Expr
699
+ b: Expr
700
+
701
+ def eval(self) -> Expr:
702
+ return polylog(self.b + 1, self.a * self.variable)
703
+
704
+
705
+ @dataclass
706
+ class UpperGammaRule(AtomicRule):
707
+ a: Expr
708
+ e: Expr
709
+
710
+ def eval(self) -> Expr:
711
+ a, e, x = self.a, self.e, self.variable
712
+ return x**e * (-a*x)**(-e) * uppergamma(e + 1, -a*x)/a
713
+
714
+
715
+ @dataclass
716
+ class EllipticFRule(AtomicRule):
717
+ a: Expr
718
+ d: Expr
719
+
720
+ def eval(self) -> Expr:
721
+ return elliptic_f(self.variable, self.d/self.a)/sqrt(self.a)
722
+
723
+
724
+ @dataclass
725
+ class EllipticERule(AtomicRule):
726
+ a: Expr
727
+ d: Expr
728
+
729
+ def eval(self) -> Expr:
730
+ return elliptic_e(self.variable, self.d/self.a)*sqrt(self.a)
731
+
732
+
733
+ class IntegralInfo(NamedTuple):
734
+ integrand: Expr
735
+ symbol: Symbol
736
+
737
+
738
+ def manual_diff(f, symbol):
739
+ """Derivative of f in form expected by find_substitutions
740
+
741
+ SymPy's derivatives for some trig functions (like cot) are not in a form
742
+ that works well with finding substitutions; this replaces the
743
+ derivatives for those particular forms with something that works better.
744
+
745
+ """
746
+ if f.args:
747
+ arg = f.args[0]
748
+ if isinstance(f, tan):
749
+ return arg.diff(symbol) * sec(arg)**2
750
+ elif isinstance(f, cot):
751
+ return -arg.diff(symbol) * csc(arg)**2
752
+ elif isinstance(f, sec):
753
+ return arg.diff(symbol) * sec(arg) * tan(arg)
754
+ elif isinstance(f, csc):
755
+ return -arg.diff(symbol) * csc(arg) * cot(arg)
756
+ elif isinstance(f, Add):
757
+ return sum(manual_diff(arg, symbol) for arg in f.args)
758
+ elif isinstance(f, Mul):
759
+ if len(f.args) == 2 and isinstance(f.args[0], Number):
760
+ return f.args[0] * manual_diff(f.args[1], symbol)
761
+ return f.diff(symbol)
762
+
763
+ def manual_subs(expr, *args):
764
+ """
765
+ A wrapper for `expr.subs(*args)` with additional logic for substitution
766
+ of invertible functions.
767
+ """
768
+ if len(args) == 1:
769
+ sequence = args[0]
770
+ if isinstance(sequence, (Dict, Mapping)):
771
+ sequence = sequence.items()
772
+ elif not iterable(sequence):
773
+ raise ValueError("Expected an iterable of (old, new) pairs")
774
+ elif len(args) == 2:
775
+ sequence = [args]
776
+ else:
777
+ raise ValueError("subs accepts either 1 or 2 arguments")
778
+
779
+ new_subs = []
780
+ for old, new in sequence:
781
+ if isinstance(old, log):
782
+ # If log(x) = y, then exp(a*log(x)) = exp(a*y)
783
+ # that is, x**a = exp(a*y). Replace nontrivial powers of x
784
+ # before subs turns them into `exp(y)**a`, but
785
+ # do not replace x itself yet, to avoid `log(exp(y))`.
786
+ x0 = old.args[0]
787
+ expr = expr.replace(lambda x: x.is_Pow and x.base == x0,
788
+ lambda x: exp(x.exp*new))
789
+ new_subs.append((x0, exp(new)))
790
+
791
+ return expr.subs(list(sequence) + new_subs)
792
+
793
+ # Method based on that on SIN, described in "Symbolic Integration: The
794
+ # Stormy Decade"
795
+
796
+ inverse_trig_functions = (atan, asin, acos, acot, acsc, asec)
797
+
798
+
799
+ def find_substitutions(integrand, symbol, u_var):
800
+ results = []
801
+
802
+ def test_subterm(u, u_diff):
803
+ if u_diff == 0:
804
+ return False
805
+ substituted = integrand / u_diff
806
+ debug("substituted: {}, u: {}, u_var: {}".format(substituted, u, u_var))
807
+ substituted = manual_subs(substituted, u, u_var).cancel()
808
+
809
+ if substituted.has_free(symbol):
810
+ return False
811
+ # avoid increasing the degree of a rational function
812
+ if integrand.is_rational_function(symbol) and substituted.is_rational_function(u_var):
813
+ deg_before = max(degree(t, symbol) for t in integrand.as_numer_denom())
814
+ deg_after = max(degree(t, u_var) for t in substituted.as_numer_denom())
815
+ if deg_after > deg_before:
816
+ return False
817
+ return substituted.as_independent(u_var, as_Add=False)
818
+
819
+ def exp_subterms(term: Expr):
820
+ linear_coeffs = []
821
+ terms = []
822
+ n = Wild('n', properties=[lambda n: n.is_Integer])
823
+ for exp_ in term.find(exp):
824
+ arg = exp_.args[0]
825
+ if symbol not in arg.free_symbols:
826
+ continue
827
+ match = arg.match(n*symbol)
828
+ if match:
829
+ linear_coeffs.append(match[n])
830
+ else:
831
+ terms.append(exp_)
832
+ if linear_coeffs:
833
+ terms.append(exp(gcd_list(linear_coeffs)*symbol))
834
+ return terms
835
+
836
+ def possible_subterms(term):
837
+ if isinstance(term, (TrigonometricFunction, HyperbolicFunction,
838
+ *inverse_trig_functions,
839
+ exp, log, Heaviside)):
840
+ return [term.args[0]]
841
+ elif isinstance(term, (chebyshevt, chebyshevu,
842
+ legendre, hermite, laguerre)):
843
+ return [term.args[1]]
844
+ elif isinstance(term, (gegenbauer, assoc_laguerre)):
845
+ return [term.args[2]]
846
+ elif isinstance(term, jacobi):
847
+ return [term.args[3]]
848
+ elif isinstance(term, Mul):
849
+ r = []
850
+ for u in term.args:
851
+ r.append(u)
852
+ r.extend(possible_subterms(u))
853
+ return r
854
+ elif isinstance(term, Pow):
855
+ r = [arg for arg in term.args if arg.has(symbol)]
856
+ if term.exp.is_Integer:
857
+ r.extend([term.base**d for d in primefactors(term.exp)
858
+ if 1 < d < abs(term.args[1])])
859
+ if term.base.is_Add:
860
+ r.extend([t for t in possible_subterms(term.base)
861
+ if t.is_Pow])
862
+ return r
863
+ elif isinstance(term, Add):
864
+ r = []
865
+ for arg in term.args:
866
+ r.append(arg)
867
+ r.extend(possible_subterms(arg))
868
+ return r
869
+ return []
870
+
871
+ for u in list(dict.fromkeys(possible_subterms(integrand) + exp_subterms(integrand))):
872
+ if u == symbol:
873
+ continue
874
+ u_diff = manual_diff(u, symbol)
875
+ new_integrand = test_subterm(u, u_diff)
876
+ if new_integrand is not False:
877
+ constant, new_integrand = new_integrand
878
+ if new_integrand == integrand.subs(symbol, u_var):
879
+ continue
880
+ substitution = (u, constant, new_integrand)
881
+ if substitution not in results:
882
+ results.append(substitution)
883
+
884
+ return results
885
+
886
+ def rewriter(condition, rewrite):
887
+ """Strategy that rewrites an integrand."""
888
+ def _rewriter(integral):
889
+ integrand, symbol = integral
890
+ debug("Integral: {} is rewritten with {} on symbol: {}".format(integrand, rewrite, symbol))
891
+ if condition(*integral):
892
+ rewritten = rewrite(*integral)
893
+ if rewritten != integrand:
894
+ substep = integral_steps(rewritten, symbol)
895
+ if not isinstance(substep, DontKnowRule) and substep:
896
+ return RewriteRule(integrand, symbol, rewritten, substep)
897
+ return _rewriter
898
+
899
+ def proxy_rewriter(condition, rewrite):
900
+ """Strategy that rewrites an integrand based on some other criteria."""
901
+ def _proxy_rewriter(criteria):
902
+ criteria, integral = criteria
903
+ integrand, symbol = integral
904
+ debug("Integral: {} is rewritten with {} on symbol: {} and criteria: {}".format(integrand, rewrite, symbol, criteria))
905
+ args = criteria + list(integral)
906
+ if condition(*args):
907
+ rewritten = rewrite(*args)
908
+ if rewritten != integrand:
909
+ return RewriteRule(integrand, symbol, rewritten, integral_steps(rewritten, symbol))
910
+ return _proxy_rewriter
911
+
912
+ def multiplexer(conditions):
913
+ """Apply the rule that matches the condition, else None"""
914
+ def multiplexer_rl(expr):
915
+ for key, rule in conditions.items():
916
+ if key(expr):
917
+ return rule(expr)
918
+ return multiplexer_rl
919
+
920
+ def alternatives(*rules):
921
+ """Strategy that makes an AlternativeRule out of multiple possible results."""
922
+ def _alternatives(integral):
923
+ alts = []
924
+ count = 0
925
+ debug("List of Alternative Rules")
926
+ for rule in rules:
927
+ count = count + 1
928
+ debug("Rule {}: {}".format(count, rule))
929
+
930
+ result = rule(integral)
931
+ if (result and not isinstance(result, DontKnowRule) and
932
+ result != integral and result not in alts):
933
+ alts.append(result)
934
+ if len(alts) == 1:
935
+ return alts[0]
936
+ elif alts:
937
+ doable = [rule for rule in alts if not rule.contains_dont_know()]
938
+ if doable:
939
+ return AlternativeRule(*integral, doable)
940
+ else:
941
+ return AlternativeRule(*integral, alts)
942
+ return _alternatives
943
+
944
+ def constant_rule(integral):
945
+ return ConstantRule(*integral)
946
+
947
+ def power_rule(integral):
948
+ integrand, symbol = integral
949
+ base, expt = integrand.as_base_exp()
950
+
951
+ if symbol not in expt.free_symbols and isinstance(base, Symbol):
952
+ if simplify(expt + 1) == 0:
953
+ return ReciprocalRule(integrand, symbol, base)
954
+ return PowerRule(integrand, symbol, base, expt)
955
+ elif symbol not in base.free_symbols and isinstance(expt, Symbol):
956
+ rule = ExpRule(integrand, symbol, base, expt)
957
+
958
+ if fuzzy_not(log(base).is_zero):
959
+ return rule
960
+ elif log(base).is_zero:
961
+ return ConstantRule(1, symbol)
962
+
963
+ return PiecewiseRule(integrand, symbol, [
964
+ (rule, Ne(log(base), 0)),
965
+ (ConstantRule(1, symbol), True)
966
+ ])
967
+
968
+ def exp_rule(integral):
969
+ integrand, symbol = integral
970
+ if isinstance(integrand.args[0], Symbol):
971
+ return ExpRule(integrand, symbol, E, integrand.args[0])
972
+
973
+
974
+ def orthogonal_poly_rule(integral):
975
+ orthogonal_poly_classes = {
976
+ jacobi: JacobiRule,
977
+ gegenbauer: GegenbauerRule,
978
+ chebyshevt: ChebyshevTRule,
979
+ chebyshevu: ChebyshevURule,
980
+ legendre: LegendreRule,
981
+ hermite: HermiteRule,
982
+ laguerre: LaguerreRule,
983
+ assoc_laguerre: AssocLaguerreRule
984
+ }
985
+ orthogonal_poly_var_index = {
986
+ jacobi: 3,
987
+ gegenbauer: 2,
988
+ assoc_laguerre: 2
989
+ }
990
+ integrand, symbol = integral
991
+ for klass in orthogonal_poly_classes:
992
+ if isinstance(integrand, klass):
993
+ var_index = orthogonal_poly_var_index.get(klass, 1)
994
+ if (integrand.args[var_index] is symbol and not
995
+ any(v.has(symbol) for v in integrand.args[:var_index])):
996
+ return orthogonal_poly_classes[klass](integrand, symbol, *integrand.args[:var_index])
997
+
998
+
999
+ _special_function_patterns: list[tuple[Type, Expr, Callable | None, tuple]] = []
1000
+ _wilds = []
1001
+ _symbol = Dummy('x')
1002
+
1003
+
1004
+ def special_function_rule(integral):
1005
+ integrand, symbol = integral
1006
+ if not _special_function_patterns:
1007
+ a = Wild('a', exclude=[_symbol], properties=[lambda x: not x.is_zero])
1008
+ b = Wild('b', exclude=[_symbol])
1009
+ c = Wild('c', exclude=[_symbol])
1010
+ d = Wild('d', exclude=[_symbol], properties=[lambda x: not x.is_zero])
1011
+ e = Wild('e', exclude=[_symbol], properties=[
1012
+ lambda x: not (x.is_nonnegative and x.is_integer)])
1013
+ _wilds.extend((a, b, c, d, e))
1014
+ # patterns consist of a SymPy class, a wildcard expr, an optional
1015
+ # condition coded as a lambda (when Wild properties are not enough),
1016
+ # followed by an applicable rule
1017
+ linear_pattern = a*_symbol + b
1018
+ quadratic_pattern = a*_symbol**2 + b*_symbol + c
1019
+ _special_function_patterns.extend((
1020
+ (Mul, exp(linear_pattern, evaluate=False)/_symbol, None, EiRule),
1021
+ (Mul, cos(linear_pattern, evaluate=False)/_symbol, None, CiRule),
1022
+ (Mul, cosh(linear_pattern, evaluate=False)/_symbol, None, ChiRule),
1023
+ (Mul, sin(linear_pattern, evaluate=False)/_symbol, None, SiRule),
1024
+ (Mul, sinh(linear_pattern, evaluate=False)/_symbol, None, ShiRule),
1025
+ (Pow, 1/log(linear_pattern, evaluate=False), None, LiRule),
1026
+ (exp, exp(quadratic_pattern, evaluate=False), None, ErfRule),
1027
+ (sin, sin(quadratic_pattern, evaluate=False), None, FresnelSRule),
1028
+ (cos, cos(quadratic_pattern, evaluate=False), None, FresnelCRule),
1029
+ (Mul, _symbol**e*exp(a*_symbol, evaluate=False), None, UpperGammaRule),
1030
+ (Mul, polylog(b, a*_symbol, evaluate=False)/_symbol, None, PolylogRule),
1031
+ (Pow, 1/sqrt(a - d*sin(_symbol, evaluate=False)**2),
1032
+ lambda a, d: a != d, EllipticFRule),
1033
+ (Pow, sqrt(a - d*sin(_symbol, evaluate=False)**2),
1034
+ lambda a, d: a != d, EllipticERule),
1035
+ ))
1036
+ _integrand = integrand.subs(symbol, _symbol)
1037
+ for type_, pattern, constraint, rule in _special_function_patterns:
1038
+ if isinstance(_integrand, type_):
1039
+ match = _integrand.match(pattern)
1040
+ if match:
1041
+ wild_vals = tuple(match.get(w) for w in _wilds
1042
+ if match.get(w) is not None)
1043
+ if constraint is None or constraint(*wild_vals):
1044
+ return rule(integrand, symbol, *wild_vals)
1045
+
1046
+
1047
+ def _add_degenerate_step(generic_cond, generic_step: Rule, degenerate_step: Rule | None) -> Rule:
1048
+ if degenerate_step is None:
1049
+ return generic_step
1050
+ if isinstance(generic_step, PiecewiseRule):
1051
+ subfunctions = [(substep, (cond & generic_cond).simplify())
1052
+ for substep, cond in generic_step.subfunctions]
1053
+ else:
1054
+ subfunctions = [(generic_step, generic_cond)]
1055
+ if isinstance(degenerate_step, PiecewiseRule):
1056
+ subfunctions += degenerate_step.subfunctions
1057
+ else:
1058
+ subfunctions.append((degenerate_step, S.true))
1059
+ return PiecewiseRule(generic_step.integrand, generic_step.variable, subfunctions)
1060
+
1061
+
1062
+ def nested_pow_rule(integral: IntegralInfo):
1063
+ # nested (c*(a+b*x)**d)**e
1064
+ integrand, x = integral
1065
+
1066
+ a_ = Wild('a', exclude=[x])
1067
+ b_ = Wild('b', exclude=[x, 0])
1068
+ pattern = a_+b_*x
1069
+ generic_cond = S.true
1070
+
1071
+ class NoMatch(Exception):
1072
+ pass
1073
+
1074
+ def _get_base_exp(expr: Expr) -> tuple[Expr, Expr]:
1075
+ if not expr.has_free(x):
1076
+ return S.One, S.Zero
1077
+ if expr.is_Mul:
1078
+ _, terms = expr.as_coeff_mul()
1079
+ if not terms:
1080
+ return S.One, S.Zero
1081
+ results = [_get_base_exp(term) for term in terms]
1082
+ bases = {b for b, _ in results}
1083
+ bases.discard(S.One)
1084
+ if len(bases) == 1:
1085
+ return bases.pop(), Add(*(e for _, e in results))
1086
+ raise NoMatch
1087
+ if expr.is_Pow:
1088
+ b, e = expr.base, expr.exp # type: ignore
1089
+ if e.has_free(x):
1090
+ raise NoMatch
1091
+ base_, sub_exp = _get_base_exp(b)
1092
+ return base_, sub_exp * e
1093
+ match = expr.match(pattern)
1094
+ if match:
1095
+ a, b = match[a_], match[b_]
1096
+ base_ = x + a/b
1097
+ nonlocal generic_cond
1098
+ generic_cond = Ne(b, 0)
1099
+ return base_, S.One
1100
+ raise NoMatch
1101
+
1102
+ try:
1103
+ base, exp_ = _get_base_exp(integrand)
1104
+ except NoMatch:
1105
+ return
1106
+ if generic_cond is S.true:
1107
+ degenerate_step = None
1108
+ else:
1109
+ # equivalent with subs(b, 0) but no need to find b
1110
+ degenerate_step = ConstantRule(integrand.subs(x, 0), x)
1111
+ generic_step = NestedPowRule(integrand, x, base, exp_)
1112
+ return _add_degenerate_step(generic_cond, generic_step, degenerate_step)
1113
+
1114
+
1115
+ def inverse_trig_rule(integral: IntegralInfo, degenerate=True):
1116
+ """
1117
+ Set degenerate=False on recursive call where coefficient of quadratic term
1118
+ is assumed non-zero.
1119
+ """
1120
+ integrand, symbol = integral
1121
+ base, exp = integrand.as_base_exp()
1122
+ a = Wild('a', exclude=[symbol])
1123
+ b = Wild('b', exclude=[symbol])
1124
+ c = Wild('c', exclude=[symbol, 0])
1125
+ match = base.match(a + b*symbol + c*symbol**2)
1126
+
1127
+ if not match:
1128
+ return
1129
+
1130
+ def make_inverse_trig(RuleClass, a, sign_a, c, sign_c, h) -> Rule:
1131
+ u_var = Dummy("u")
1132
+ rewritten = 1/sqrt(sign_a*a + sign_c*c*(symbol-h)**2) # a>0, c>0
1133
+ quadratic_base = sqrt(c/a)*(symbol-h)
1134
+ constant = 1/sqrt(c)
1135
+ u_func = None
1136
+ if quadratic_base is not symbol:
1137
+ u_func = quadratic_base
1138
+ quadratic_base = u_var
1139
+ standard_form = 1/sqrt(sign_a + sign_c*quadratic_base**2)
1140
+ substep = RuleClass(standard_form, quadratic_base)
1141
+ if constant != 1:
1142
+ substep = ConstantTimesRule(constant*standard_form, symbol, constant, standard_form, substep)
1143
+ if u_func is not None:
1144
+ substep = URule(rewritten, symbol, u_var, u_func, substep)
1145
+ if h != 0:
1146
+ substep = CompleteSquareRule(integrand, symbol, rewritten, substep)
1147
+ return substep
1148
+
1149
+ a, b, c = [match.get(i, S.Zero) for i in (a, b, c)]
1150
+ generic_cond = Ne(c, 0)
1151
+ if not degenerate or generic_cond is S.true:
1152
+ degenerate_step = None
1153
+ elif b.is_zero:
1154
+ degenerate_step = ConstantRule(a ** exp, symbol)
1155
+ else:
1156
+ degenerate_step = sqrt_linear_rule(IntegralInfo((a + b * symbol) ** exp, symbol))
1157
+
1158
+ if simplify(2*exp + 1) == 0:
1159
+ h, k = -b/(2*c), a - b**2/(4*c) # rewrite base to k + c*(symbol-h)**2
1160
+ non_square_cond = Ne(k, 0)
1161
+ square_step = None
1162
+ if non_square_cond is not S.true:
1163
+ square_step = NestedPowRule(1/sqrt(c*(symbol-h)**2), symbol, symbol-h, S.NegativeOne)
1164
+ if non_square_cond is S.false:
1165
+ return square_step
1166
+ generic_step = ReciprocalSqrtQuadraticRule(integrand, symbol, a, b, c)
1167
+ step = _add_degenerate_step(non_square_cond, generic_step, square_step)
1168
+ if k.is_real and c.is_real:
1169
+ # list of ((rule, base_exp, a, sign_a, b, sign_b), condition)
1170
+ rules = []
1171
+ for args, cond in ( # don't apply ArccoshRule to x**2-1
1172
+ ((ArcsinRule, k, 1, -c, -1, h), And(k > 0, c < 0)), # 1-x**2
1173
+ ((ArcsinhRule, k, 1, c, 1, h), And(k > 0, c > 0)), # 1+x**2
1174
+ ):
1175
+ if cond is S.true:
1176
+ return make_inverse_trig(*args)
1177
+ if cond is not S.false:
1178
+ rules.append((make_inverse_trig(*args), cond))
1179
+ if rules:
1180
+ if not k.is_positive: # conditions are not thorough, need fall back rule
1181
+ rules.append((generic_step, S.true))
1182
+ step = PiecewiseRule(integrand, symbol, rules)
1183
+ else:
1184
+ step = generic_step
1185
+ return _add_degenerate_step(generic_cond, step, degenerate_step)
1186
+ if exp == S.Half:
1187
+ step = SqrtQuadraticRule(integrand, symbol, a, b, c)
1188
+ return _add_degenerate_step(generic_cond, step, degenerate_step)
1189
+
1190
+
1191
+ def add_rule(integral):
1192
+ integrand, symbol = integral
1193
+ results = [integral_steps(g, symbol)
1194
+ for g in integrand.as_ordered_terms()]
1195
+ return None if None in results else AddRule(integrand, symbol, results)
1196
+
1197
+
1198
+ def mul_rule(integral: IntegralInfo):
1199
+ integrand, symbol = integral
1200
+
1201
+ # Constant times function case
1202
+ coeff, f = integrand.as_independent(symbol)
1203
+ if coeff != 1:
1204
+ next_step = integral_steps(f, symbol)
1205
+ if next_step is not None:
1206
+ return ConstantTimesRule(integrand, symbol, coeff, f, next_step)
1207
+
1208
+
1209
+ def _parts_rule(integrand, symbol) -> tuple[Expr, Expr, Expr, Expr, Rule] | None:
1210
+ # LIATE rule:
1211
+ # log, inverse trig, algebraic, trigonometric, exponential
1212
+ def pull_out_algebraic(integrand):
1213
+ integrand = integrand.cancel().together()
1214
+ # iterating over Piecewise args would not work here
1215
+ algebraic = ([] if isinstance(integrand, Piecewise) or not integrand.is_Mul
1216
+ else [arg for arg in integrand.args if arg.is_algebraic_expr(symbol)])
1217
+ if algebraic:
1218
+ u = Mul(*algebraic)
1219
+ dv = (integrand / u).cancel()
1220
+ return u, dv
1221
+
1222
+ def pull_out_u(*functions) -> Callable[[Expr], tuple[Expr, Expr] | None]:
1223
+ def pull_out_u_rl(integrand: Expr) -> tuple[Expr, Expr] | None:
1224
+ if any(integrand.has(f) for f in functions):
1225
+ args = [arg for arg in integrand.args
1226
+ if any(isinstance(arg, cls) for cls in functions)]
1227
+ if args:
1228
+ u = Mul(*args) # type: ignore
1229
+ dv = integrand / u
1230
+ return u, dv
1231
+ return None
1232
+
1233
+ return pull_out_u_rl
1234
+
1235
+ liate_rules = [pull_out_u(log), pull_out_u(*inverse_trig_functions),
1236
+ pull_out_algebraic, pull_out_u(sin, cos),
1237
+ pull_out_u(exp)]
1238
+
1239
+
1240
+ dummy = Dummy("temporary")
1241
+ # we can integrate log(x) and atan(x) by setting dv = 1
1242
+ if isinstance(integrand, (log, *inverse_trig_functions)):
1243
+ integrand = dummy * integrand
1244
+
1245
+ for index, rule in enumerate(liate_rules):
1246
+ result = rule(integrand)
1247
+
1248
+ if result:
1249
+ u, dv = result
1250
+
1251
+ # Don't pick u to be a constant if possible
1252
+ if symbol not in u.free_symbols and not u.has(dummy):
1253
+ return None
1254
+
1255
+ u = u.subs(dummy, 1)
1256
+ dv = dv.subs(dummy, 1)
1257
+
1258
+ # Don't pick a non-polynomial algebraic to be differentiated
1259
+ if rule == pull_out_algebraic and not u.is_polynomial(symbol):
1260
+ return None
1261
+ # Don't trade one logarithm for another
1262
+ if isinstance(u, log):
1263
+ rec_dv = 1/dv
1264
+ if (rec_dv.is_polynomial(symbol) and
1265
+ degree(rec_dv, symbol) == 1):
1266
+ return None
1267
+
1268
+ # Can integrate a polynomial times OrthogonalPolynomial
1269
+ if rule == pull_out_algebraic:
1270
+ if dv.is_Derivative or dv.has(TrigonometricFunction) or \
1271
+ isinstance(dv, OrthogonalPolynomial):
1272
+ v_step = integral_steps(dv, symbol)
1273
+ if v_step.contains_dont_know():
1274
+ return None
1275
+ else:
1276
+ du = u.diff(symbol)
1277
+ v = v_step.eval()
1278
+ return u, dv, v, du, v_step
1279
+
1280
+ # make sure dv is amenable to integration
1281
+ accept = False
1282
+ if index < 2: # log and inverse trig are usually worth trying
1283
+ accept = True
1284
+ elif (rule == pull_out_algebraic and dv.args and
1285
+ all(isinstance(a, (sin, cos, exp))
1286
+ for a in dv.args)):
1287
+ accept = True
1288
+ else:
1289
+ for lrule in liate_rules[index + 1:]:
1290
+ r = lrule(integrand)
1291
+ if r and r[0].subs(dummy, 1).equals(dv):
1292
+ accept = True
1293
+ break
1294
+
1295
+ if accept:
1296
+ du = u.diff(symbol)
1297
+ v_step = integral_steps(simplify(dv), symbol)
1298
+ if not v_step.contains_dont_know():
1299
+ v = v_step.eval()
1300
+ return u, dv, v, du, v_step
1301
+ return None
1302
+
1303
+
1304
+ def parts_rule(integral):
1305
+ integrand, symbol = integral
1306
+ constant, integrand = integrand.as_coeff_Mul()
1307
+
1308
+ result = _parts_rule(integrand, symbol)
1309
+
1310
+ steps = []
1311
+ if result:
1312
+ u, dv, v, du, v_step = result
1313
+ debug("u : {}, dv : {}, v : {}, du : {}, v_step: {}".format(u, dv, v, du, v_step))
1314
+ steps.append(result)
1315
+
1316
+ if isinstance(v, Integral):
1317
+ return
1318
+
1319
+ # Set a limit on the number of times u can be used
1320
+ if isinstance(u, (sin, cos, exp, sinh, cosh)):
1321
+ cachekey = u.xreplace({symbol: _cache_dummy})
1322
+ if _parts_u_cache[cachekey] > 2:
1323
+ return
1324
+ _parts_u_cache[cachekey] += 1
1325
+
1326
+ # Try cyclic integration by parts a few times
1327
+ for _ in range(4):
1328
+ debug("Cyclic integration {} with v: {}, du: {}, integrand: {}".format(_, v, du, integrand))
1329
+ coefficient = ((v * du) / integrand).cancel()
1330
+ if coefficient == 1:
1331
+ break
1332
+ if symbol not in coefficient.free_symbols:
1333
+ rule = CyclicPartsRule(integrand, symbol,
1334
+ [PartsRule(None, None, u, dv, v_step, None)
1335
+ for (u, dv, v, du, v_step) in steps],
1336
+ (-1) ** len(steps) * coefficient)
1337
+ if (constant != 1) and rule:
1338
+ rule = ConstantTimesRule(constant * integrand, symbol, constant, integrand, rule)
1339
+ return rule
1340
+
1341
+ # _parts_rule is sensitive to constants, factor it out
1342
+ next_constant, next_integrand = (v * du).as_coeff_Mul()
1343
+ result = _parts_rule(next_integrand, symbol)
1344
+
1345
+ if result:
1346
+ u, dv, v, du, v_step = result
1347
+ u *= next_constant
1348
+ du *= next_constant
1349
+ steps.append((u, dv, v, du, v_step))
1350
+ else:
1351
+ break
1352
+
1353
+ def make_second_step(steps, integrand):
1354
+ if steps:
1355
+ u, dv, v, du, v_step = steps[0]
1356
+ return PartsRule(integrand, symbol, u, dv, v_step, make_second_step(steps[1:], v * du))
1357
+ return integral_steps(integrand, symbol)
1358
+
1359
+ if steps:
1360
+ u, dv, v, du, v_step = steps[0]
1361
+ rule = PartsRule(integrand, symbol, u, dv, v_step, make_second_step(steps[1:], v * du))
1362
+ if (constant != 1) and rule:
1363
+ rule = ConstantTimesRule(constant * integrand, symbol, constant, integrand, rule)
1364
+ return rule
1365
+
1366
+
1367
+ def trig_rule(integral):
1368
+ integrand, symbol = integral
1369
+ if integrand == sin(symbol):
1370
+ return SinRule(integrand, symbol)
1371
+ if integrand == cos(symbol):
1372
+ return CosRule(integrand, symbol)
1373
+ if integrand == sec(symbol)**2:
1374
+ return Sec2Rule(integrand, symbol)
1375
+ if integrand == csc(symbol)**2:
1376
+ return Csc2Rule(integrand, symbol)
1377
+
1378
+ if isinstance(integrand, tan):
1379
+ rewritten = sin(*integrand.args) / cos(*integrand.args)
1380
+ elif isinstance(integrand, cot):
1381
+ rewritten = cos(*integrand.args) / sin(*integrand.args)
1382
+ elif isinstance(integrand, sec):
1383
+ arg = integrand.args[0]
1384
+ rewritten = ((sec(arg)**2 + tan(arg) * sec(arg)) /
1385
+ (sec(arg) + tan(arg)))
1386
+ elif isinstance(integrand, csc):
1387
+ arg = integrand.args[0]
1388
+ rewritten = ((csc(arg)**2 + cot(arg) * csc(arg)) /
1389
+ (csc(arg) + cot(arg)))
1390
+ else:
1391
+ return
1392
+
1393
+ return RewriteRule(integrand, symbol, rewritten, integral_steps(rewritten, symbol))
1394
+
1395
+ def trig_product_rule(integral: IntegralInfo):
1396
+ integrand, symbol = integral
1397
+ if integrand == sec(symbol) * tan(symbol):
1398
+ return SecTanRule(integrand, symbol)
1399
+ if integrand == csc(symbol) * cot(symbol):
1400
+ return CscCotRule(integrand, symbol)
1401
+
1402
+
1403
+ def quadratic_denom_rule(integral):
1404
+ integrand, symbol = integral
1405
+ a = Wild('a', exclude=[symbol])
1406
+ b = Wild('b', exclude=[symbol])
1407
+ c = Wild('c', exclude=[symbol])
1408
+
1409
+ match = integrand.match(a / (b * symbol ** 2 + c))
1410
+
1411
+ if match:
1412
+ a, b, c = match[a], match[b], match[c]
1413
+ general_rule = ArctanRule(integrand, symbol, a, b, c)
1414
+ if b.is_extended_real and c.is_extended_real:
1415
+ positive_cond = c/b > 0
1416
+ if positive_cond is S.true:
1417
+ return general_rule
1418
+ coeff = a/(2*sqrt(-c)*sqrt(b))
1419
+ constant = sqrt(-c/b)
1420
+ r1 = 1/(symbol-constant)
1421
+ r2 = 1/(symbol+constant)
1422
+ log_steps = [ReciprocalRule(r1, symbol, symbol-constant),
1423
+ ConstantTimesRule(-r2, symbol, -1, r2, ReciprocalRule(r2, symbol, symbol+constant))]
1424
+ rewritten = sub = r1 - r2
1425
+ negative_step = AddRule(sub, symbol, log_steps)
1426
+ if coeff != 1:
1427
+ rewritten = Mul(coeff, sub, evaluate=False)
1428
+ negative_step = ConstantTimesRule(rewritten, symbol, coeff, sub, negative_step)
1429
+ negative_step = RewriteRule(integrand, symbol, rewritten, negative_step)
1430
+ if positive_cond is S.false:
1431
+ return negative_step
1432
+ return PiecewiseRule(integrand, symbol, [(general_rule, positive_cond), (negative_step, S.true)])
1433
+
1434
+ power = PowerRule(integrand, symbol, symbol, -2)
1435
+ if b != 1:
1436
+ power = ConstantTimesRule(integrand, symbol, 1/b, symbol**-2, power)
1437
+
1438
+ return PiecewiseRule(integrand, symbol, [(general_rule, Ne(c, 0)), (power, True)])
1439
+
1440
+ d = Wild('d', exclude=[symbol])
1441
+ match2 = integrand.match(a / (b * symbol ** 2 + c * symbol + d))
1442
+ if match2:
1443
+ b, c = match2[b], match2[c]
1444
+ if b.is_zero:
1445
+ return
1446
+ u = Dummy('u')
1447
+ u_func = symbol + c/(2*b)
1448
+ integrand2 = integrand.subs(symbol, u - c / (2*b))
1449
+ next_step = integral_steps(integrand2, u)
1450
+ if next_step:
1451
+ return URule(integrand2, symbol, u, u_func, next_step)
1452
+ else:
1453
+ return
1454
+ e = Wild('e', exclude=[symbol])
1455
+ match3 = integrand.match((a* symbol + b) / (c * symbol ** 2 + d * symbol + e))
1456
+ if match3:
1457
+ a, b, c, d, e = match3[a], match3[b], match3[c], match3[d], match3[e]
1458
+ if c.is_zero:
1459
+ return
1460
+ denominator = c * symbol**2 + d * symbol + e
1461
+ const = a/(2*c)
1462
+ numer1 = (2*c*symbol+d)
1463
+ numer2 = - const*d + b
1464
+ u = Dummy('u')
1465
+ step1 = URule(integrand, symbol,
1466
+ u, denominator, integral_steps(u**(-1), u))
1467
+ if const != 1:
1468
+ step1 = ConstantTimesRule(const*numer1/denominator, symbol,
1469
+ const, numer1/denominator, step1)
1470
+ if numer2.is_zero:
1471
+ return step1
1472
+ step2 = integral_steps(numer2/denominator, symbol)
1473
+ substeps = AddRule(integrand, symbol, [step1, step2])
1474
+ rewriten = const*numer1/denominator+numer2/denominator
1475
+ return RewriteRule(integrand, symbol, rewriten, substeps)
1476
+
1477
+ return
1478
+
1479
+
1480
+ def sqrt_linear_rule(integral: IntegralInfo):
1481
+ """
1482
+ Substitute common (a+b*x)**(1/n)
1483
+ """
1484
+ integrand, x = integral
1485
+ a = Wild('a', exclude=[x])
1486
+ b = Wild('b', exclude=[x, 0])
1487
+ a0 = b0 = 0
1488
+ bases, qs, bs = [], [], []
1489
+ for pow_ in integrand.find(Pow): # collect all (a+b*x)**(p/q)
1490
+ base, exp_ = pow_.base, pow_.exp
1491
+ if exp_.is_Integer or x not in base.free_symbols: # skip 1/x and sqrt(2)
1492
+ continue
1493
+ if not exp_.is_Rational: # exclude x**pi
1494
+ return
1495
+ match = base.match(a+b*x)
1496
+ if not match: # skip non-linear
1497
+ continue # for sqrt(x+sqrt(x)), although base is non-linear, we can still substitute sqrt(x)
1498
+ a1, b1 = match[a], match[b]
1499
+ if a0*b1 != a1*b0 or not (b0/b1).is_nonnegative: # cannot transform sqrt(x) to sqrt(x+1) or sqrt(-x)
1500
+ return
1501
+ if b0 == 0 or (b0/b1 > 1) is S.true: # choose the latter of sqrt(2*x) and sqrt(x) as representative
1502
+ a0, b0 = a1, b1
1503
+ bases.append(base)
1504
+ bs.append(b1)
1505
+ qs.append(exp_.q)
1506
+ if b0 == 0: # no such pattern found
1507
+ return
1508
+ q0: Integer = lcm_list(qs)
1509
+ u_x = (a0 + b0*x)**(1/q0)
1510
+ u = Dummy("u")
1511
+ substituted = integrand.subs({base**(S.One/q): (b/b0)**(S.One/q)*u**(q0/q)
1512
+ for base, b, q in zip(bases, bs, qs)}).subs(x, (u**q0-a0)/b0)
1513
+ substep = integral_steps(substituted*u**(q0-1)*q0/b0, u)
1514
+ if not substep.contains_dont_know():
1515
+ step: Rule = URule(integrand, x, u, u_x, substep)
1516
+ generic_cond = Ne(b0, 0)
1517
+ if generic_cond is not S.true: # possible degenerate case
1518
+ simplified = integrand.subs(dict.fromkeys(bs, 0))
1519
+ degenerate_step = integral_steps(simplified, x)
1520
+ step = PiecewiseRule(integrand, x, [(step, generic_cond), (degenerate_step, S.true)])
1521
+ return step
1522
+
1523
+
1524
+ def sqrt_quadratic_rule(integral: IntegralInfo, degenerate=True):
1525
+ integrand, x = integral
1526
+ a = Wild('a', exclude=[x])
1527
+ b = Wild('b', exclude=[x])
1528
+ c = Wild('c', exclude=[x, 0])
1529
+ f = Wild('f')
1530
+ n = Wild('n', properties=[lambda n: n.is_Integer and n.is_odd])
1531
+ match = integrand.match(f*sqrt(a+b*x+c*x**2)**n)
1532
+ if not match:
1533
+ return
1534
+ a, b, c, f, n = match[a], match[b], match[c], match[f], match[n]
1535
+ f_poly = f.as_poly(x)
1536
+ if f_poly is None:
1537
+ return
1538
+
1539
+ generic_cond = Ne(c, 0)
1540
+ if not degenerate or generic_cond is S.true:
1541
+ degenerate_step = None
1542
+ elif b.is_zero:
1543
+ degenerate_step = integral_steps(f*sqrt(a)**n, x)
1544
+ else:
1545
+ degenerate_step = sqrt_linear_rule(IntegralInfo(f*sqrt(a+b*x)**n, x))
1546
+
1547
+ def sqrt_quadratic_denom_rule(numer_poly: Poly, integrand: Expr):
1548
+ denom = sqrt(a+b*x+c*x**2)
1549
+ deg = numer_poly.degree()
1550
+ if deg <= 1:
1551
+ # integrand == (d+e*x)/sqrt(a+b*x+c*x**2)
1552
+ e, d = numer_poly.all_coeffs() if deg == 1 else (S.Zero, numer_poly.as_expr())
1553
+ # rewrite numerator to A*(2*c*x+b) + B
1554
+ A = e/(2*c)
1555
+ B = d-A*b
1556
+ pre_substitute = (2*c*x+b)/denom
1557
+ constant_step: Rule | None = None
1558
+ linear_step: Rule | None = None
1559
+ if A != 0:
1560
+ u = Dummy("u")
1561
+ pow_rule = PowerRule(1/sqrt(u), u, u, -S.Half)
1562
+ linear_step = URule(pre_substitute, x, u, a+b*x+c*x**2, pow_rule)
1563
+ if A != 1:
1564
+ linear_step = ConstantTimesRule(A*pre_substitute, x, A, pre_substitute, linear_step)
1565
+ if B != 0:
1566
+ constant_step = inverse_trig_rule(IntegralInfo(1/denom, x), degenerate=False)
1567
+ if B != 1:
1568
+ constant_step = ConstantTimesRule(B/denom, x, B, 1/denom, constant_step) # type: ignore
1569
+ if linear_step and constant_step:
1570
+ add = Add(A*pre_substitute, B/denom, evaluate=False)
1571
+ step: Rule | None = RewriteRule(integrand, x, add, AddRule(add, x, [linear_step, constant_step]))
1572
+ else:
1573
+ step = linear_step or constant_step
1574
+ else:
1575
+ coeffs = numer_poly.all_coeffs()
1576
+ step = SqrtQuadraticDenomRule(integrand, x, a, b, c, coeffs)
1577
+ return step
1578
+
1579
+ if n > 0: # rewrite poly * sqrt(s)**(2*k-1) to poly*s**k / sqrt(s)
1580
+ numer_poly = f_poly * (a+b*x+c*x**2)**((n+1)/2)
1581
+ rewritten = numer_poly.as_expr()/sqrt(a+b*x+c*x**2)
1582
+ substep = sqrt_quadratic_denom_rule(numer_poly, rewritten)
1583
+ generic_step = RewriteRule(integrand, x, rewritten, substep)
1584
+ elif n == -1:
1585
+ generic_step = sqrt_quadratic_denom_rule(f_poly, integrand)
1586
+ else:
1587
+ return # todo: handle n < -1 case
1588
+ return _add_degenerate_step(generic_cond, generic_step, degenerate_step)
1589
+
1590
+
1591
+ def hyperbolic_rule(integral: tuple[Expr, Symbol]):
1592
+ integrand, symbol = integral
1593
+ if isinstance(integrand, HyperbolicFunction) and integrand.args[0] == symbol:
1594
+ if integrand.func == sinh:
1595
+ return SinhRule(integrand, symbol)
1596
+ if integrand.func == cosh:
1597
+ return CoshRule(integrand, symbol)
1598
+ u = Dummy('u')
1599
+ if integrand.func == tanh:
1600
+ rewritten = sinh(symbol)/cosh(symbol)
1601
+ return RewriteRule(integrand, symbol, rewritten,
1602
+ URule(rewritten, symbol, u, cosh(symbol), ReciprocalRule(1/u, u, u)))
1603
+ if integrand.func == coth:
1604
+ rewritten = cosh(symbol)/sinh(symbol)
1605
+ return RewriteRule(integrand, symbol, rewritten,
1606
+ URule(rewritten, symbol, u, sinh(symbol), ReciprocalRule(1/u, u, u)))
1607
+ else:
1608
+ rewritten = integrand.rewrite(tanh)
1609
+ if integrand.func == sech:
1610
+ return RewriteRule(integrand, symbol, rewritten,
1611
+ URule(rewritten, symbol, u, tanh(symbol/2),
1612
+ ArctanRule(2/(u**2 + 1), u, S(2), S.One, S.One)))
1613
+ if integrand.func == csch:
1614
+ return RewriteRule(integrand, symbol, rewritten,
1615
+ URule(rewritten, symbol, u, tanh(symbol/2),
1616
+ ReciprocalRule(1/u, u, u)))
1617
+
1618
+ @cacheit
1619
+ def make_wilds(symbol):
1620
+ a = Wild('a', exclude=[symbol])
1621
+ b = Wild('b', exclude=[symbol])
1622
+ m = Wild('m', exclude=[symbol], properties=[lambda n: isinstance(n, Integer)])
1623
+ n = Wild('n', exclude=[symbol], properties=[lambda n: isinstance(n, Integer)])
1624
+
1625
+ return a, b, m, n
1626
+
1627
+ @cacheit
1628
+ def sincos_pattern(symbol):
1629
+ a, b, m, n = make_wilds(symbol)
1630
+ pattern = sin(a*symbol)**m * cos(b*symbol)**n
1631
+
1632
+ return pattern, a, b, m, n
1633
+
1634
+ @cacheit
1635
+ def tansec_pattern(symbol):
1636
+ a, b, m, n = make_wilds(symbol)
1637
+ pattern = tan(a*symbol)**m * sec(b*symbol)**n
1638
+
1639
+ return pattern, a, b, m, n
1640
+
1641
+ @cacheit
1642
+ def cotcsc_pattern(symbol):
1643
+ a, b, m, n = make_wilds(symbol)
1644
+ pattern = cot(a*symbol)**m * csc(b*symbol)**n
1645
+
1646
+ return pattern, a, b, m, n
1647
+
1648
+ @cacheit
1649
+ def heaviside_pattern(symbol):
1650
+ m = Wild('m', exclude=[symbol])
1651
+ b = Wild('b', exclude=[symbol])
1652
+ g = Wild('g')
1653
+ pattern = Heaviside(m*symbol + b) * g
1654
+
1655
+ return pattern, m, b, g
1656
+
1657
+ def uncurry(func):
1658
+ def uncurry_rl(args):
1659
+ return func(*args)
1660
+ return uncurry_rl
1661
+
1662
+ def trig_rewriter(rewrite):
1663
+ def trig_rewriter_rl(args):
1664
+ a, b, m, n, integrand, symbol = args
1665
+ rewritten = rewrite(a, b, m, n, integrand, symbol)
1666
+ if rewritten != integrand:
1667
+ return RewriteRule(integrand, symbol, rewritten, integral_steps(rewritten, symbol))
1668
+ return trig_rewriter_rl
1669
+
1670
+ sincos_botheven_condition = uncurry(
1671
+ lambda a, b, m, n, i, s: m.is_even and n.is_even and
1672
+ m.is_nonnegative and n.is_nonnegative)
1673
+
1674
+ sincos_botheven = trig_rewriter(
1675
+ lambda a, b, m, n, i, symbol: ( (((1 - cos(2*a*symbol)) / 2) ** (m / 2)) *
1676
+ (((1 + cos(2*b*symbol)) / 2) ** (n / 2)) ))
1677
+
1678
+ sincos_sinodd_condition = uncurry(lambda a, b, m, n, i, s: m.is_odd and m >= 3)
1679
+
1680
+ sincos_sinodd = trig_rewriter(
1681
+ lambda a, b, m, n, i, symbol: ( (1 - cos(a*symbol)**2)**((m - 1) / 2) *
1682
+ sin(a*symbol) *
1683
+ cos(b*symbol) ** n))
1684
+
1685
+ sincos_cosodd_condition = uncurry(lambda a, b, m, n, i, s: n.is_odd and n >= 3)
1686
+
1687
+ sincos_cosodd = trig_rewriter(
1688
+ lambda a, b, m, n, i, symbol: ( (1 - sin(b*symbol)**2)**((n - 1) / 2) *
1689
+ cos(b*symbol) *
1690
+ sin(a*symbol) ** m))
1691
+
1692
+ tansec_seceven_condition = uncurry(lambda a, b, m, n, i, s: n.is_even and n >= 4)
1693
+ tansec_seceven = trig_rewriter(
1694
+ lambda a, b, m, n, i, symbol: ( (1 + tan(b*symbol)**2) ** (n/2 - 1) *
1695
+ sec(b*symbol)**2 *
1696
+ tan(a*symbol) ** m ))
1697
+
1698
+ tansec_tanodd_condition = uncurry(lambda a, b, m, n, i, s: m.is_odd)
1699
+ tansec_tanodd = trig_rewriter(
1700
+ lambda a, b, m, n, i, symbol: ( (sec(a*symbol)**2 - 1) ** ((m - 1) / 2) *
1701
+ tan(a*symbol) *
1702
+ sec(b*symbol) ** n ))
1703
+
1704
+ tan_tansquared_condition = uncurry(lambda a, b, m, n, i, s: m == 2 and n == 0)
1705
+ tan_tansquared = trig_rewriter(
1706
+ lambda a, b, m, n, i, symbol: ( sec(a*symbol)**2 - 1))
1707
+
1708
+ cotcsc_csceven_condition = uncurry(lambda a, b, m, n, i, s: n.is_even and n >= 4)
1709
+ cotcsc_csceven = trig_rewriter(
1710
+ lambda a, b, m, n, i, symbol: ( (1 + cot(b*symbol)**2) ** (n/2 - 1) *
1711
+ csc(b*symbol)**2 *
1712
+ cot(a*symbol) ** m ))
1713
+
1714
+ cotcsc_cotodd_condition = uncurry(lambda a, b, m, n, i, s: m.is_odd)
1715
+ cotcsc_cotodd = trig_rewriter(
1716
+ lambda a, b, m, n, i, symbol: ( (csc(a*symbol)**2 - 1) ** ((m - 1) / 2) *
1717
+ cot(a*symbol) *
1718
+ csc(b*symbol) ** n ))
1719
+
1720
+ def trig_sincos_rule(integral):
1721
+ integrand, symbol = integral
1722
+
1723
+ if any(integrand.has(f) for f in (sin, cos)):
1724
+ pattern, a, b, m, n = sincos_pattern(symbol)
1725
+ match = integrand.match(pattern)
1726
+ if not match:
1727
+ return
1728
+
1729
+ return multiplexer({
1730
+ sincos_botheven_condition: sincos_botheven,
1731
+ sincos_sinodd_condition: sincos_sinodd,
1732
+ sincos_cosodd_condition: sincos_cosodd
1733
+ })(tuple(
1734
+ [match.get(i, S.Zero) for i in (a, b, m, n)] +
1735
+ [integrand, symbol]))
1736
+
1737
+ def trig_tansec_rule(integral):
1738
+ integrand, symbol = integral
1739
+
1740
+ integrand = integrand.subs({
1741
+ 1 / cos(symbol): sec(symbol)
1742
+ })
1743
+
1744
+ if any(integrand.has(f) for f in (tan, sec)):
1745
+ pattern, a, b, m, n = tansec_pattern(symbol)
1746
+ match = integrand.match(pattern)
1747
+ if not match:
1748
+ return
1749
+
1750
+ return multiplexer({
1751
+ tansec_tanodd_condition: tansec_tanodd,
1752
+ tansec_seceven_condition: tansec_seceven,
1753
+ tan_tansquared_condition: tan_tansquared
1754
+ })(tuple(
1755
+ [match.get(i, S.Zero) for i in (a, b, m, n)] +
1756
+ [integrand, symbol]))
1757
+
1758
+ def trig_cotcsc_rule(integral):
1759
+ integrand, symbol = integral
1760
+ integrand = integrand.subs({
1761
+ 1 / sin(symbol): csc(symbol),
1762
+ 1 / tan(symbol): cot(symbol),
1763
+ cos(symbol) / tan(symbol): cot(symbol)
1764
+ })
1765
+
1766
+ if any(integrand.has(f) for f in (cot, csc)):
1767
+ pattern, a, b, m, n = cotcsc_pattern(symbol)
1768
+ match = integrand.match(pattern)
1769
+ if not match:
1770
+ return
1771
+
1772
+ return multiplexer({
1773
+ cotcsc_cotodd_condition: cotcsc_cotodd,
1774
+ cotcsc_csceven_condition: cotcsc_csceven
1775
+ })(tuple(
1776
+ [match.get(i, S.Zero) for i in (a, b, m, n)] +
1777
+ [integrand, symbol]))
1778
+
1779
+ def trig_sindouble_rule(integral):
1780
+ integrand, symbol = integral
1781
+ a = Wild('a', exclude=[sin(2*symbol)])
1782
+ match = integrand.match(sin(2*symbol)*a)
1783
+ if match:
1784
+ sin_double = 2*sin(symbol)*cos(symbol)/sin(2*symbol)
1785
+ return integral_steps(integrand * sin_double, symbol)
1786
+
1787
+ def trig_powers_products_rule(integral):
1788
+ return do_one(null_safe(trig_sincos_rule),
1789
+ null_safe(trig_tansec_rule),
1790
+ null_safe(trig_cotcsc_rule),
1791
+ null_safe(trig_sindouble_rule))(integral)
1792
+
1793
+ def trig_substitution_rule(integral):
1794
+ integrand, symbol = integral
1795
+ A = Wild('a', exclude=[0, symbol])
1796
+ B = Wild('b', exclude=[0, symbol])
1797
+ theta = Dummy("theta")
1798
+ target_pattern = A + B*symbol**2
1799
+
1800
+ matches = integrand.find(target_pattern)
1801
+ for expr in matches:
1802
+ match = expr.match(target_pattern)
1803
+ a = match.get(A, S.Zero)
1804
+ b = match.get(B, S.Zero)
1805
+
1806
+ a_positive = ((a.is_number and a > 0) or a.is_positive)
1807
+ b_positive = ((b.is_number and b > 0) or b.is_positive)
1808
+ a_negative = ((a.is_number and a < 0) or a.is_negative)
1809
+ b_negative = ((b.is_number and b < 0) or b.is_negative)
1810
+ x_func = None
1811
+ if a_positive and b_positive:
1812
+ # a**2 + b*x**2. Assume sec(theta) > 0, -pi/2 < theta < pi/2
1813
+ x_func = (sqrt(a)/sqrt(b)) * tan(theta)
1814
+ # Do not restrict the domain: tan(theta) takes on any real
1815
+ # value on the interval -pi/2 < theta < pi/2 so x takes on
1816
+ # any value
1817
+ restriction = True
1818
+ elif a_positive and b_negative:
1819
+ # a**2 - b*x**2. Assume cos(theta) > 0, -pi/2 < theta < pi/2
1820
+ constant = sqrt(a)/sqrt(-b)
1821
+ x_func = constant * sin(theta)
1822
+ restriction = And(symbol > -constant, symbol < constant)
1823
+ elif a_negative and b_positive:
1824
+ # b*x**2 - a**2. Assume sin(theta) > 0, 0 < theta < pi
1825
+ constant = sqrt(-a)/sqrt(b)
1826
+ x_func = constant * sec(theta)
1827
+ restriction = And(symbol > -constant, symbol < constant)
1828
+ if x_func:
1829
+ # Manually simplify sqrt(trig(theta)**2) to trig(theta)
1830
+ # Valid due to assumed domain restriction
1831
+ substitutions = {}
1832
+ for f in [sin, cos, tan,
1833
+ sec, csc, cot]:
1834
+ substitutions[sqrt(f(theta)**2)] = f(theta)
1835
+ substitutions[sqrt(f(theta)**(-2))] = 1/f(theta)
1836
+
1837
+ replaced = integrand.subs(symbol, x_func).trigsimp()
1838
+ replaced = manual_subs(replaced, substitutions)
1839
+ if not replaced.has(symbol):
1840
+ replaced *= manual_diff(x_func, theta)
1841
+ replaced = replaced.trigsimp()
1842
+ secants = replaced.find(1/cos(theta))
1843
+ if secants:
1844
+ replaced = replaced.xreplace({
1845
+ 1/cos(theta): sec(theta)
1846
+ })
1847
+
1848
+ substep = integral_steps(replaced, theta)
1849
+ if not substep.contains_dont_know():
1850
+ return TrigSubstitutionRule(integrand, symbol,
1851
+ theta, x_func, replaced, substep, restriction)
1852
+
1853
+ def heaviside_rule(integral):
1854
+ integrand, symbol = integral
1855
+ pattern, m, b, g = heaviside_pattern(symbol)
1856
+ match = integrand.match(pattern)
1857
+ if match and 0 != match[g]:
1858
+ # f = Heaviside(m*x + b)*g
1859
+ substep = integral_steps(match[g], symbol)
1860
+ m, b = match[m], match[b]
1861
+ return HeavisideRule(integrand, symbol, m*symbol + b, -b/m, substep)
1862
+
1863
+
1864
+ def dirac_delta_rule(integral: IntegralInfo):
1865
+ integrand, x = integral
1866
+ if len(integrand.args) == 1:
1867
+ n = S.Zero
1868
+ else:
1869
+ n = integrand.args[1] # type: ignore
1870
+ if not n.is_Integer or n < 0:
1871
+ return
1872
+ a, b = Wild('a', exclude=[x]), Wild('b', exclude=[x, 0])
1873
+ match = integrand.args[0].match(a+b*x)
1874
+ if not match:
1875
+ return
1876
+ a, b = match[a], match[b]
1877
+ generic_cond = Ne(b, 0)
1878
+ if generic_cond is S.true:
1879
+ degenerate_step = None
1880
+ else:
1881
+ degenerate_step = ConstantRule(DiracDelta(a, n), x)
1882
+ generic_step = DiracDeltaRule(integrand, x, n, a, b)
1883
+ return _add_degenerate_step(generic_cond, generic_step, degenerate_step)
1884
+
1885
+
1886
+ def substitution_rule(integral):
1887
+ integrand, symbol = integral
1888
+
1889
+ u_var = Dummy("u")
1890
+ substitutions = find_substitutions(integrand, symbol, u_var)
1891
+ count = 0
1892
+ if substitutions:
1893
+ debug("List of Substitution Rules")
1894
+ ways = []
1895
+ for u_func, c, substituted in substitutions:
1896
+ subrule = integral_steps(substituted, u_var)
1897
+ count = count + 1
1898
+ debug("Rule {}: {}".format(count, subrule))
1899
+
1900
+ if subrule.contains_dont_know():
1901
+ continue
1902
+
1903
+ if simplify(c - 1) != 0:
1904
+ _, denom = c.as_numer_denom()
1905
+ if subrule:
1906
+ subrule = ConstantTimesRule(c * substituted, u_var, c, substituted, subrule)
1907
+
1908
+ if denom.free_symbols:
1909
+ piecewise = []
1910
+ could_be_zero = []
1911
+
1912
+ if isinstance(denom, Mul):
1913
+ could_be_zero = denom.args
1914
+ else:
1915
+ could_be_zero.append(denom)
1916
+
1917
+ for expr in could_be_zero:
1918
+ if not fuzzy_not(expr.is_zero):
1919
+ substep = integral_steps(manual_subs(integrand, expr, 0), symbol)
1920
+
1921
+ if substep:
1922
+ piecewise.append((
1923
+ substep,
1924
+ Eq(expr, 0)
1925
+ ))
1926
+ piecewise.append((subrule, True))
1927
+ subrule = PiecewiseRule(substituted, symbol, piecewise)
1928
+
1929
+ ways.append(URule(integrand, symbol, u_var, u_func, subrule))
1930
+
1931
+ if len(ways) > 1:
1932
+ return AlternativeRule(integrand, symbol, ways)
1933
+ elif ways:
1934
+ return ways[0]
1935
+
1936
+
1937
+ partial_fractions_rule = rewriter(
1938
+ lambda integrand, symbol: integrand.is_rational_function(),
1939
+ lambda integrand, symbol: integrand.apart(symbol))
1940
+
1941
+ cancel_rule = rewriter(
1942
+ # lambda integrand, symbol: integrand.is_algebraic_expr(),
1943
+ # lambda integrand, symbol: isinstance(integrand, Mul),
1944
+ lambda integrand, symbol: True,
1945
+ lambda integrand, symbol: integrand.cancel())
1946
+
1947
+ distribute_expand_rule = rewriter(
1948
+ lambda integrand, symbol: (
1949
+ isinstance(integrand, (Pow, Mul)) or all(arg.is_Pow or arg.is_polynomial(symbol) for arg in integrand.args)),
1950
+ lambda integrand, symbol: integrand.expand())
1951
+
1952
+ trig_expand_rule = rewriter(
1953
+ # If there are trig functions with different arguments, expand them
1954
+ lambda integrand, symbol: (
1955
+ len({a.args[0] for a in integrand.atoms(TrigonometricFunction)}) > 1),
1956
+ lambda integrand, symbol: integrand.expand(trig=True))
1957
+
1958
+ def derivative_rule(integral):
1959
+ integrand = integral[0]
1960
+ diff_variables = integrand.variables
1961
+ undifferentiated_function = integrand.expr
1962
+ integrand_variables = undifferentiated_function.free_symbols
1963
+
1964
+ if integral.symbol in integrand_variables:
1965
+ if integral.symbol in diff_variables:
1966
+ return DerivativeRule(*integral)
1967
+ else:
1968
+ return DontKnowRule(integrand, integral.symbol)
1969
+ else:
1970
+ return ConstantRule(*integral)
1971
+
1972
+ def rewrites_rule(integral):
1973
+ integrand, symbol = integral
1974
+
1975
+ if integrand.match(1/cos(symbol)):
1976
+ rewritten = integrand.subs(1/cos(symbol), sec(symbol))
1977
+ return RewriteRule(integrand, symbol, rewritten, integral_steps(rewritten, symbol))
1978
+
1979
+ def fallback_rule(integral):
1980
+ return DontKnowRule(*integral)
1981
+
1982
+ # Cache is used to break cyclic integrals.
1983
+ # Need to use the same dummy variable in cached expressions for them to match.
1984
+ # Also record "u" of integration by parts, to avoid infinite repetition.
1985
+ _integral_cache: dict[Expr, Expr | None] = {}
1986
+ _parts_u_cache: dict[Expr, int] = defaultdict(int)
1987
+ _cache_dummy = Dummy("z")
1988
+
1989
+ def integral_steps(integrand, symbol, **options):
1990
+ """Returns the steps needed to compute an integral.
1991
+
1992
+ Explanation
1993
+ ===========
1994
+
1995
+ This function attempts to mirror what a student would do by hand as
1996
+ closely as possible.
1997
+
1998
+ SymPy Gamma uses this to provide a step-by-step explanation of an
1999
+ integral. The code it uses to format the results of this function can be
2000
+ found at
2001
+ https://github.com/sympy/sympy_gamma/blob/master/app/logic/intsteps.py.
2002
+
2003
+ Examples
2004
+ ========
2005
+
2006
+ >>> from sympy import exp, sin
2007
+ >>> from sympy.integrals.manualintegrate import integral_steps
2008
+ >>> from sympy.abc import x
2009
+ >>> print(repr(integral_steps(exp(x) / (1 + exp(2 * x)), x))) \
2010
+ # doctest: +NORMALIZE_WHITESPACE
2011
+ URule(integrand=exp(x)/(exp(2*x) + 1), variable=x, u_var=_u, u_func=exp(x),
2012
+ substep=ArctanRule(integrand=1/(_u**2 + 1), variable=_u, a=1, b=1, c=1))
2013
+ >>> print(repr(integral_steps(sin(x), x))) \
2014
+ # doctest: +NORMALIZE_WHITESPACE
2015
+ SinRule(integrand=sin(x), variable=x)
2016
+ >>> print(repr(integral_steps((x**2 + 3)**2, x))) \
2017
+ # doctest: +NORMALIZE_WHITESPACE
2018
+ RewriteRule(integrand=(x**2 + 3)**2, variable=x, rewritten=x**4 + 6*x**2 + 9,
2019
+ substep=AddRule(integrand=x**4 + 6*x**2 + 9, variable=x,
2020
+ substeps=[PowerRule(integrand=x**4, variable=x, base=x, exp=4),
2021
+ ConstantTimesRule(integrand=6*x**2, variable=x, constant=6, other=x**2,
2022
+ substep=PowerRule(integrand=x**2, variable=x, base=x, exp=2)),
2023
+ ConstantRule(integrand=9, variable=x)]))
2024
+
2025
+ Returns
2026
+ =======
2027
+
2028
+ rule : Rule
2029
+ The first step; most rules have substeps that must also be
2030
+ considered. These substeps can be evaluated using ``manualintegrate``
2031
+ to obtain a result.
2032
+
2033
+ """
2034
+ cachekey = integrand.xreplace({symbol: _cache_dummy})
2035
+ if cachekey in _integral_cache:
2036
+ if _integral_cache[cachekey] is None:
2037
+ # Stop this attempt, because it leads around in a loop
2038
+ return DontKnowRule(integrand, symbol)
2039
+ else:
2040
+ # TODO: This is for future development, as currently
2041
+ # _integral_cache gets no values other than None
2042
+ return (_integral_cache[cachekey].xreplace(_cache_dummy, symbol),
2043
+ symbol)
2044
+ else:
2045
+ _integral_cache[cachekey] = None
2046
+
2047
+ integral = IntegralInfo(integrand, symbol)
2048
+
2049
+ def key(integral):
2050
+ integrand = integral.integrand
2051
+
2052
+ if symbol not in integrand.free_symbols:
2053
+ return Number
2054
+ for cls in (Symbol, TrigonometricFunction, OrthogonalPolynomial):
2055
+ if isinstance(integrand, cls):
2056
+ return cls
2057
+ return type(integrand)
2058
+
2059
+ def integral_is_subclass(*klasses):
2060
+ def _integral_is_subclass(integral):
2061
+ k = key(integral)
2062
+ return k and issubclass(k, klasses)
2063
+ return _integral_is_subclass
2064
+
2065
+ result = do_one(
2066
+ null_safe(special_function_rule),
2067
+ null_safe(switch(key, {
2068
+ Pow: do_one(null_safe(power_rule), null_safe(inverse_trig_rule),
2069
+ null_safe(sqrt_linear_rule),
2070
+ null_safe(quadratic_denom_rule)),
2071
+ Symbol: power_rule,
2072
+ exp: exp_rule,
2073
+ Add: add_rule,
2074
+ Mul: do_one(null_safe(mul_rule), null_safe(trig_product_rule),
2075
+ null_safe(heaviside_rule), null_safe(quadratic_denom_rule),
2076
+ null_safe(sqrt_linear_rule),
2077
+ null_safe(sqrt_quadratic_rule)),
2078
+ Derivative: derivative_rule,
2079
+ TrigonometricFunction: trig_rule,
2080
+ Heaviside: heaviside_rule,
2081
+ DiracDelta: dirac_delta_rule,
2082
+ OrthogonalPolynomial: orthogonal_poly_rule,
2083
+ Number: constant_rule
2084
+ })),
2085
+ do_one(
2086
+ null_safe(trig_rule),
2087
+ null_safe(hyperbolic_rule),
2088
+ null_safe(alternatives(
2089
+ rewrites_rule,
2090
+ substitution_rule,
2091
+ condition(
2092
+ integral_is_subclass(Mul, Pow),
2093
+ partial_fractions_rule),
2094
+ condition(
2095
+ integral_is_subclass(Mul, Pow),
2096
+ cancel_rule),
2097
+ condition(
2098
+ integral_is_subclass(Mul, log,
2099
+ *inverse_trig_functions),
2100
+ parts_rule),
2101
+ condition(
2102
+ integral_is_subclass(Mul, Pow),
2103
+ distribute_expand_rule),
2104
+ trig_powers_products_rule,
2105
+ trig_expand_rule
2106
+ )),
2107
+ null_safe(condition(integral_is_subclass(Mul, Pow), nested_pow_rule)),
2108
+ null_safe(trig_substitution_rule)
2109
+ ),
2110
+ fallback_rule)(integral)
2111
+ del _integral_cache[cachekey]
2112
+ return result
2113
+
2114
+
2115
+ def manualintegrate(f, var):
2116
+ """manualintegrate(f, var)
2117
+
2118
+ Explanation
2119
+ ===========
2120
+
2121
+ Compute indefinite integral of a single variable using an algorithm that
2122
+ resembles what a student would do by hand.
2123
+
2124
+ Unlike :func:`~.integrate`, var can only be a single symbol.
2125
+
2126
+ Examples
2127
+ ========
2128
+
2129
+ >>> from sympy import sin, cos, tan, exp, log, integrate
2130
+ >>> from sympy.integrals.manualintegrate import manualintegrate
2131
+ >>> from sympy.abc import x
2132
+ >>> manualintegrate(1 / x, x)
2133
+ log(x)
2134
+ >>> integrate(1/x)
2135
+ log(x)
2136
+ >>> manualintegrate(log(x), x)
2137
+ x*log(x) - x
2138
+ >>> integrate(log(x))
2139
+ x*log(x) - x
2140
+ >>> manualintegrate(exp(x) / (1 + exp(2 * x)), x)
2141
+ atan(exp(x))
2142
+ >>> integrate(exp(x) / (1 + exp(2 * x)))
2143
+ RootSum(4*_z**2 + 1, Lambda(_i, _i*log(2*_i + exp(x))))
2144
+ >>> manualintegrate(cos(x)**4 * sin(x), x)
2145
+ -cos(x)**5/5
2146
+ >>> integrate(cos(x)**4 * sin(x), x)
2147
+ -cos(x)**5/5
2148
+ >>> manualintegrate(cos(x)**4 * sin(x)**3, x)
2149
+ cos(x)**7/7 - cos(x)**5/5
2150
+ >>> integrate(cos(x)**4 * sin(x)**3, x)
2151
+ cos(x)**7/7 - cos(x)**5/5
2152
+ >>> manualintegrate(tan(x), x)
2153
+ -log(cos(x))
2154
+ >>> integrate(tan(x), x)
2155
+ -log(cos(x))
2156
+
2157
+ See Also
2158
+ ========
2159
+
2160
+ sympy.integrals.integrals.integrate
2161
+ sympy.integrals.integrals.Integral.doit
2162
+ sympy.integrals.integrals.Integral
2163
+ """
2164
+ result = integral_steps(f, var).eval()
2165
+ # Clear the cache of u-parts
2166
+ _parts_u_cache.clear()
2167
+ # If we got Piecewise with two parts, put generic first
2168
+ if isinstance(result, Piecewise) and len(result.args) == 2:
2169
+ cond = result.args[0][1]
2170
+ if isinstance(cond, Eq) and result.args[1][1] == True:
2171
+ result = result.func(
2172
+ (result.args[1][0], Ne(*cond.args)),
2173
+ (result.args[0][0], True))
2174
+ return result
.venv/lib/python3.12/site-packages/sympy/integrals/meijerint.py ADDED
@@ -0,0 +1,2191 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ """
2
+ Integrate functions by rewriting them as Meijer G-functions.
3
+
4
+ There are three user-visible functions that can be used by other parts of the
5
+ sympy library to solve various integration problems:
6
+
7
+ - meijerint_indefinite
8
+ - meijerint_definite
9
+ - meijerint_inversion
10
+
11
+ They can be used to compute, respectively, indefinite integrals, definite
12
+ integrals over intervals of the real line, and inverse laplace-type integrals
13
+ (from c-I*oo to c+I*oo). See the respective docstrings for details.
14
+
15
+ The main references for this are:
16
+
17
+ [L] Luke, Y. L. (1969), The Special Functions and Their Approximations,
18
+ Volume 1
19
+
20
+ [R] Kelly B. Roach. Meijer G Function Representations.
21
+ In: Proceedings of the 1997 International Symposium on Symbolic and
22
+ Algebraic Computation, pages 205-211, New York, 1997. ACM.
23
+
24
+ [P] A. P. Prudnikov, Yu. A. Brychkov and O. I. Marichev (1990).
25
+ Integrals and Series: More Special Functions, Vol. 3,.
26
+ Gordon and Breach Science Publisher
27
+ """
28
+
29
+ from __future__ import annotations
30
+ import itertools
31
+
32
+ from sympy import SYMPY_DEBUG
33
+ from sympy.core import S, Expr
34
+ from sympy.core.add import Add
35
+ from sympy.core.basic import Basic
36
+ from sympy.core.cache import cacheit
37
+ from sympy.core.containers import Tuple
38
+ from sympy.core.exprtools import factor_terms
39
+ from sympy.core.function import (expand, expand_mul, expand_power_base,
40
+ expand_trig, Function)
41
+ from sympy.core.mul import Mul
42
+ from sympy.core.intfunc import ilcm
43
+ from sympy.core.numbers import Rational, pi
44
+ from sympy.core.relational import Eq, Ne, _canonical_coeff
45
+ from sympy.core.sorting import default_sort_key, ordered
46
+ from sympy.core.symbol import Dummy, symbols, Wild, Symbol
47
+ from sympy.core.sympify import sympify
48
+ from sympy.functions.combinatorial.factorials import factorial
49
+ from sympy.functions.elementary.complexes import (re, im, arg, Abs, sign,
50
+ unpolarify, polarify, polar_lift, principal_branch, unbranched_argument,
51
+ periodic_argument)
52
+ from sympy.functions.elementary.exponential import exp, exp_polar, log
53
+ from sympy.functions.elementary.integers import ceiling
54
+ from sympy.functions.elementary.hyperbolic import (cosh, sinh,
55
+ _rewrite_hyperbolics_as_exp, HyperbolicFunction)
56
+ from sympy.functions.elementary.miscellaneous import sqrt
57
+ from sympy.functions.elementary.piecewise import Piecewise, piecewise_fold
58
+ from sympy.functions.elementary.trigonometric import (cos, sin, sinc,
59
+ TrigonometricFunction)
60
+ from sympy.functions.special.bessel import besselj, bessely, besseli, besselk
61
+ from sympy.functions.special.delta_functions import DiracDelta, Heaviside
62
+ from sympy.functions.special.elliptic_integrals import elliptic_k, elliptic_e
63
+ from sympy.functions.special.error_functions import (erf, erfc, erfi, Ei,
64
+ expint, Si, Ci, Shi, Chi, fresnels, fresnelc)
65
+ from sympy.functions.special.gamma_functions import gamma
66
+ from sympy.functions.special.hyper import hyper, meijerg
67
+ from sympy.functions.special.singularity_functions import SingularityFunction
68
+ from .integrals import Integral
69
+ from sympy.logic.boolalg import And, Or, BooleanAtom, Not, BooleanFunction
70
+ from sympy.polys import cancel, factor
71
+ from sympy.utilities.iterables import multiset_partitions
72
+ from sympy.utilities.misc import debug as _debug
73
+ from sympy.utilities.misc import debugf as _debugf
74
+
75
+ # keep this at top for easy reference
76
+ z = Dummy('z')
77
+
78
+
79
+ def _has(res, *f):
80
+ # return True if res has f; in the case of Piecewise
81
+ # only return True if *all* pieces have f
82
+ res = piecewise_fold(res)
83
+ if getattr(res, 'is_Piecewise', False):
84
+ return all(_has(i, *f) for i in res.args)
85
+ return res.has(*f)
86
+
87
+
88
+ def _create_lookup_table(table):
89
+ """ Add formulae for the function -> meijerg lookup table. """
90
+ def wild(n):
91
+ return Wild(n, exclude=[z])
92
+ p, q, a, b, c = list(map(wild, 'pqabc'))
93
+ n = Wild('n', properties=[lambda x: x.is_Integer and x > 0])
94
+ t = p*z**q
95
+
96
+ def add(formula, an, ap, bm, bq, arg=t, fac=S.One, cond=True, hint=True):
97
+ table.setdefault(_mytype(formula, z), []).append((formula,
98
+ [(fac, meijerg(an, ap, bm, bq, arg))], cond, hint))
99
+
100
+ def addi(formula, inst, cond, hint=True):
101
+ table.setdefault(
102
+ _mytype(formula, z), []).append((formula, inst, cond, hint))
103
+
104
+ def constant(a):
105
+ return [(a, meijerg([1], [], [], [0], z)),
106
+ (a, meijerg([], [1], [0], [], z))]
107
+ table[()] = [(a, constant(a), True, True)]
108
+
109
+ # [P], Section 8.
110
+ class IsNonPositiveInteger(Function):
111
+
112
+ @classmethod
113
+ def eval(cls, arg):
114
+ arg = unpolarify(arg)
115
+ if arg.is_Integer is True:
116
+ return arg <= 0
117
+
118
+ # Section 8.4.2
119
+ # TODO this needs more polar_lift (c/f entry for exp)
120
+ add(Heaviside(t - b)*(t - b)**(a - 1), [a], [], [], [0], t/b,
121
+ gamma(a)*b**(a - 1), And(b > 0))
122
+ add(Heaviside(b - t)*(b - t)**(a - 1), [], [a], [0], [], t/b,
123
+ gamma(a)*b**(a - 1), And(b > 0))
124
+ add(Heaviside(z - (b/p)**(1/q))*(t - b)**(a - 1), [a], [], [], [0], t/b,
125
+ gamma(a)*b**(a - 1), And(b > 0))
126
+ add(Heaviside((b/p)**(1/q) - z)*(b - t)**(a - 1), [], [a], [0], [], t/b,
127
+ gamma(a)*b**(a - 1), And(b > 0))
128
+ add((b + t)**(-a), [1 - a], [], [0], [], t/b, b**(-a)/gamma(a),
129
+ hint=Not(IsNonPositiveInteger(a)))
130
+ add(Abs(b - t)**(-a), [1 - a], [(1 - a)/2], [0], [(1 - a)/2], t/b,
131
+ 2*sin(pi*a/2)*gamma(1 - a)*Abs(b)**(-a), re(a) < 1)
132
+ add((t**a - b**a)/(t - b), [0, a], [], [0, a], [], t/b,
133
+ b**(a - 1)*sin(a*pi)/pi)
134
+
135
+ # 12
136
+ def A1(r, sign, nu):
137
+ return pi**Rational(-1, 2)*(-sign*nu/2)**(1 - 2*r)
138
+
139
+ def tmpadd(r, sgn):
140
+ # XXX the a**2 is bad for matching
141
+ add((sqrt(a**2 + t) + sgn*a)**b/(a**2 + t)**r,
142
+ [(1 + b)/2, 1 - 2*r + b/2], [],
143
+ [(b - sgn*b)/2], [(b + sgn*b)/2], t/a**2,
144
+ a**(b - 2*r)*A1(r, sgn, b))
145
+ tmpadd(0, 1)
146
+ tmpadd(0, -1)
147
+ tmpadd(S.Half, 1)
148
+ tmpadd(S.Half, -1)
149
+
150
+ # 13
151
+ def tmpadd(r, sgn):
152
+ add((sqrt(a + p*z**q) + sgn*sqrt(p)*z**(q/2))**b/(a + p*z**q)**r,
153
+ [1 - r + sgn*b/2], [1 - r - sgn*b/2], [0, S.Half], [],
154
+ p*z**q/a, a**(b/2 - r)*A1(r, sgn, b))
155
+ tmpadd(0, 1)
156
+ tmpadd(0, -1)
157
+ tmpadd(S.Half, 1)
158
+ tmpadd(S.Half, -1)
159
+ # (those after look obscure)
160
+
161
+ # Section 8.4.3
162
+ add(exp(polar_lift(-1)*t), [], [], [0], [])
163
+
164
+ # TODO can do sin^n, sinh^n by expansion ... where?
165
+ # 8.4.4 (hyperbolic functions)
166
+ add(sinh(t), [], [1], [S.Half], [1, 0], t**2/4, pi**Rational(3, 2))
167
+ add(cosh(t), [], [S.Half], [0], [S.Half, S.Half], t**2/4, pi**Rational(3, 2))
168
+
169
+ # Section 8.4.5
170
+ # TODO can do t + a. but can also do by expansion... (XXX not really)
171
+ add(sin(t), [], [], [S.Half], [0], t**2/4, sqrt(pi))
172
+ add(cos(t), [], [], [0], [S.Half], t**2/4, sqrt(pi))
173
+
174
+ # Section 8.4.6 (sinc function)
175
+ add(sinc(t), [], [], [0], [Rational(-1, 2)], t**2/4, sqrt(pi)/2)
176
+
177
+ # Section 8.5.5
178
+ def make_log1(subs):
179
+ N = subs[n]
180
+ return [(S.NegativeOne**N*factorial(N),
181
+ meijerg([], [1]*(N + 1), [0]*(N + 1), [], t))]
182
+
183
+ def make_log2(subs):
184
+ N = subs[n]
185
+ return [(factorial(N),
186
+ meijerg([1]*(N + 1), [], [], [0]*(N + 1), t))]
187
+ # TODO these only hold for positive p, and can be made more general
188
+ # but who uses log(x)*Heaviside(a-x) anyway ...
189
+ # TODO also it would be nice to derive them recursively ...
190
+ addi(log(t)**n*Heaviside(1 - t), make_log1, True)
191
+ addi(log(t)**n*Heaviside(t - 1), make_log2, True)
192
+
193
+ def make_log3(subs):
194
+ return make_log1(subs) + make_log2(subs)
195
+ addi(log(t)**n, make_log3, True)
196
+ addi(log(t + a),
197
+ constant(log(a)) + [(S.One, meijerg([1, 1], [], [1], [0], t/a))],
198
+ True)
199
+ addi(log(Abs(t - a)), constant(log(Abs(a))) +
200
+ [(pi, meijerg([1, 1], [S.Half], [1], [0, S.Half], t/a))],
201
+ True)
202
+ # TODO log(x)/(x+a) and log(x)/(x-1) can also be done. should they
203
+ # be derivable?
204
+ # TODO further formulae in this section seem obscure
205
+
206
+ # Sections 8.4.9-10
207
+ # TODO
208
+
209
+ # Section 8.4.11
210
+ addi(Ei(t),
211
+ constant(-S.ImaginaryUnit*pi) + [(S.NegativeOne, meijerg([], [1], [0, 0], [],
212
+ t*polar_lift(-1)))],
213
+ True)
214
+
215
+ # Section 8.4.12
216
+ add(Si(t), [1], [], [S.Half], [0, 0], t**2/4, sqrt(pi)/2)
217
+ add(Ci(t), [], [1], [0, 0], [S.Half], t**2/4, -sqrt(pi)/2)
218
+
219
+ # Section 8.4.13
220
+ add(Shi(t), [S.Half], [], [0], [Rational(-1, 2), Rational(-1, 2)], polar_lift(-1)*t**2/4,
221
+ t*sqrt(pi)/4)
222
+ add(Chi(t), [], [S.Half, 1], [0, 0], [S.Half, S.Half], t**2/4, -
223
+ pi**S('3/2')/2)
224
+
225
+ # generalized exponential integral
226
+ add(expint(a, t), [], [a], [a - 1, 0], [], t)
227
+
228
+ # Section 8.4.14
229
+ add(erf(t), [1], [], [S.Half], [0], t**2, 1/sqrt(pi))
230
+ # TODO exp(-x)*erf(I*x) does not work
231
+ add(erfc(t), [], [1], [0, S.Half], [], t**2, 1/sqrt(pi))
232
+ # This formula for erfi(z) yields a wrong(?) minus sign
233
+ #add(erfi(t), [1], [], [S.Half], [0], -t**2, I/sqrt(pi))
234
+ add(erfi(t), [S.Half], [], [0], [Rational(-1, 2)], -t**2, t/sqrt(pi))
235
+
236
+ # Fresnel Integrals
237
+ add(fresnels(t), [1], [], [Rational(3, 4)], [0, Rational(1, 4)], pi**2*t**4/16, S.Half)
238
+ add(fresnelc(t), [1], [], [Rational(1, 4)], [0, Rational(3, 4)], pi**2*t**4/16, S.Half)
239
+
240
+ ##### bessel-type functions #####
241
+ # Section 8.4.19
242
+ add(besselj(a, t), [], [], [a/2], [-a/2], t**2/4)
243
+
244
+ # all of the following are derivable
245
+ #add(sin(t)*besselj(a, t), [Rational(1, 4), Rational(3, 4)], [], [(1+a)/2],
246
+ # [-a/2, a/2, (1-a)/2], t**2, 1/sqrt(2))
247
+ #add(cos(t)*besselj(a, t), [Rational(1, 4), Rational(3, 4)], [], [a/2],
248
+ # [-a/2, (1+a)/2, (1-a)/2], t**2, 1/sqrt(2))
249
+ #add(besselj(a, t)**2, [S.Half], [], [a], [-a, 0], t**2, 1/sqrt(pi))
250
+ #add(besselj(a, t)*besselj(b, t), [0, S.Half], [], [(a + b)/2],
251
+ # [-(a+b)/2, (a - b)/2, (b - a)/2], t**2, 1/sqrt(pi))
252
+
253
+ # Section 8.4.20
254
+ add(bessely(a, t), [], [-(a + 1)/2], [a/2, -a/2], [-(a + 1)/2], t**2/4)
255
+
256
+ # TODO all of the following should be derivable
257
+ #add(sin(t)*bessely(a, t), [Rational(1, 4), Rational(3, 4)], [(1 - a - 1)/2],
258
+ # [(1 + a)/2, (1 - a)/2], [(1 - a - 1)/2, (1 - 1 - a)/2, (1 - 1 + a)/2],
259
+ # t**2, 1/sqrt(2))
260
+ #add(cos(t)*bessely(a, t), [Rational(1, 4), Rational(3, 4)], [(0 - a - 1)/2],
261
+ # [(0 + a)/2, (0 - a)/2], [(0 - a - 1)/2, (1 - 0 - a)/2, (1 - 0 + a)/2],
262
+ # t**2, 1/sqrt(2))
263
+ #add(besselj(a, t)*bessely(b, t), [0, S.Half], [(a - b - 1)/2],
264
+ # [(a + b)/2, (a - b)/2], [(a - b - 1)/2, -(a + b)/2, (b - a)/2],
265
+ # t**2, 1/sqrt(pi))
266
+ #addi(bessely(a, t)**2,
267
+ # [(2/sqrt(pi), meijerg([], [S.Half, S.Half - a], [0, a, -a],
268
+ # [S.Half - a], t**2)),
269
+ # (1/sqrt(pi), meijerg([S.Half], [], [a], [-a, 0], t**2))],
270
+ # True)
271
+ #addi(bessely(a, t)*bessely(b, t),
272
+ # [(2/sqrt(pi), meijerg([], [0, S.Half, (1 - a - b)/2],
273
+ # [(a + b)/2, (a - b)/2, (b - a)/2, -(a + b)/2],
274
+ # [(1 - a - b)/2], t**2)),
275
+ # (1/sqrt(pi), meijerg([0, S.Half], [], [(a + b)/2],
276
+ # [-(a + b)/2, (a - b)/2, (b - a)/2], t**2))],
277
+ # True)
278
+
279
+ # Section 8.4.21 ?
280
+ # Section 8.4.22
281
+ add(besseli(a, t), [], [(1 + a)/2], [a/2], [-a/2, (1 + a)/2], t**2/4, pi)
282
+ # TODO many more formulas. should all be derivable
283
+
284
+ # Section 8.4.23
285
+ add(besselk(a, t), [], [], [a/2, -a/2], [], t**2/4, S.Half)
286
+ # TODO many more formulas. should all be derivable
287
+
288
+ # Complete elliptic integrals K(z) and E(z)
289
+ add(elliptic_k(t), [S.Half, S.Half], [], [0], [0], -t, S.Half)
290
+ add(elliptic_e(t), [S.Half, 3*S.Half], [], [0], [0], -t, Rational(-1, 2)/2)
291
+
292
+
293
+ ####################################################################
294
+ # First some helper functions.
295
+ ####################################################################
296
+
297
+ from sympy.utilities.timeutils import timethis
298
+ timeit = timethis('meijerg')
299
+
300
+
301
+ def _mytype(f: Basic, x: Symbol) -> tuple[type[Basic], ...]:
302
+ """ Create a hashable entity describing the type of f. """
303
+ def key(x: type[Basic]) -> tuple[int, int, str]:
304
+ return x.class_key()
305
+
306
+ if x not in f.free_symbols:
307
+ return ()
308
+ elif f.is_Function:
309
+ return type(f),
310
+ return tuple(sorted((t for a in f.args for t in _mytype(a, x)), key=key))
311
+
312
+
313
+ class _CoeffExpValueError(ValueError):
314
+ """
315
+ Exception raised by _get_coeff_exp, for internal use only.
316
+ """
317
+ pass
318
+
319
+
320
+ def _get_coeff_exp(expr, x):
321
+ """
322
+ When expr is known to be of the form c*x**b, with c and/or b possibly 1,
323
+ return c, b.
324
+
325
+ Examples
326
+ ========
327
+
328
+ >>> from sympy.abc import x, a, b
329
+ >>> from sympy.integrals.meijerint import _get_coeff_exp
330
+ >>> _get_coeff_exp(a*x**b, x)
331
+ (a, b)
332
+ >>> _get_coeff_exp(x, x)
333
+ (1, 1)
334
+ >>> _get_coeff_exp(2*x, x)
335
+ (2, 1)
336
+ >>> _get_coeff_exp(x**3, x)
337
+ (1, 3)
338
+ """
339
+ from sympy.simplify import powsimp
340
+ (c, m) = expand_power_base(powsimp(expr)).as_coeff_mul(x)
341
+ if not m:
342
+ return c, S.Zero
343
+ [m] = m
344
+ if m.is_Pow:
345
+ if m.base != x:
346
+ raise _CoeffExpValueError('expr not of form a*x**b')
347
+ return c, m.exp
348
+ elif m == x:
349
+ return c, S.One
350
+ else:
351
+ raise _CoeffExpValueError('expr not of form a*x**b: %s' % expr)
352
+
353
+
354
+ def _exponents(expr, x):
355
+ """
356
+ Find the exponents of ``x`` (not including zero) in ``expr``.
357
+
358
+ Examples
359
+ ========
360
+
361
+ >>> from sympy.integrals.meijerint import _exponents
362
+ >>> from sympy.abc import x, y
363
+ >>> from sympy import sin
364
+ >>> _exponents(x, x)
365
+ {1}
366
+ >>> _exponents(x**2, x)
367
+ {2}
368
+ >>> _exponents(x**2 + x, x)
369
+ {1, 2}
370
+ >>> _exponents(x**3*sin(x + x**y) + 1/x, x)
371
+ {-1, 1, 3, y}
372
+ """
373
+ def _exponents_(expr, x, res):
374
+ if expr == x:
375
+ res.update([1])
376
+ return
377
+ if expr.is_Pow and expr.base == x:
378
+ res.update([expr.exp])
379
+ return
380
+ for argument in expr.args:
381
+ _exponents_(argument, x, res)
382
+ res = set()
383
+ _exponents_(expr, x, res)
384
+ return res
385
+
386
+
387
+ def _functions(expr, x):
388
+ """ Find the types of functions in expr, to estimate the complexity. """
389
+ return {e.func for e in expr.atoms(Function) if x in e.free_symbols}
390
+
391
+
392
+ def _find_splitting_points(expr, x):
393
+ """
394
+ Find numbers a such that a linear substitution x -> x + a would
395
+ (hopefully) simplify expr.
396
+
397
+ Examples
398
+ ========
399
+
400
+ >>> from sympy.integrals.meijerint import _find_splitting_points as fsp
401
+ >>> from sympy import sin
402
+ >>> from sympy.abc import x
403
+ >>> fsp(x, x)
404
+ {0}
405
+ >>> fsp((x-1)**3, x)
406
+ {1}
407
+ >>> fsp(sin(x+3)*x, x)
408
+ {-3, 0}
409
+ """
410
+ p, q = [Wild(n, exclude=[x]) for n in 'pq']
411
+
412
+ def compute_innermost(expr, res):
413
+ if not isinstance(expr, Expr):
414
+ return
415
+ m = expr.match(p*x + q)
416
+ if m and m[p] != 0:
417
+ res.add(-m[q]/m[p])
418
+ return
419
+ if expr.is_Atom:
420
+ return
421
+ for argument in expr.args:
422
+ compute_innermost(argument, res)
423
+ innermost = set()
424
+ compute_innermost(expr, innermost)
425
+ return innermost
426
+
427
+
428
+ def _split_mul(f, x):
429
+ """
430
+ Split expression ``f`` into fac, po, g, where fac is a constant factor,
431
+ po = x**s for some s independent of s, and g is "the rest".
432
+
433
+ Examples
434
+ ========
435
+
436
+ >>> from sympy.integrals.meijerint import _split_mul
437
+ >>> from sympy import sin
438
+ >>> from sympy.abc import s, x
439
+ >>> _split_mul((3*x)**s*sin(x**2)*x, x)
440
+ (3**s, x*x**s, sin(x**2))
441
+ """
442
+ fac = S.One
443
+ po = S.One
444
+ g = S.One
445
+ f = expand_power_base(f)
446
+
447
+ args = Mul.make_args(f)
448
+ for a in args:
449
+ if a == x:
450
+ po *= x
451
+ elif x not in a.free_symbols:
452
+ fac *= a
453
+ else:
454
+ if a.is_Pow and x not in a.exp.free_symbols:
455
+ c, t = a.base.as_coeff_mul(x)
456
+ if t != (x,):
457
+ c, t = expand_mul(a.base).as_coeff_mul(x)
458
+ if t == (x,):
459
+ po *= x**a.exp
460
+ fac *= unpolarify(polarify(c**a.exp, subs=False))
461
+ continue
462
+ g *= a
463
+
464
+ return fac, po, g
465
+
466
+
467
+ def _mul_args(f):
468
+ """
469
+ Return a list ``L`` such that ``Mul(*L) == f``.
470
+
471
+ If ``f`` is not a ``Mul`` or ``Pow``, ``L=[f]``.
472
+ If ``f=g**n`` for an integer ``n``, ``L=[g]*n``.
473
+ If ``f`` is a ``Mul``, ``L`` comes from applying ``_mul_args`` to all factors of ``f``.
474
+ """
475
+ args = Mul.make_args(f)
476
+ gs = []
477
+ for g in args:
478
+ if g.is_Pow and g.exp.is_Integer:
479
+ n = g.exp
480
+ base = g.base
481
+ if n < 0:
482
+ n = -n
483
+ base = 1/base
484
+ gs += [base]*n
485
+ else:
486
+ gs.append(g)
487
+ return gs
488
+
489
+
490
+ def _mul_as_two_parts(f):
491
+ """
492
+ Find all the ways to split ``f`` into a product of two terms.
493
+ Return None on failure.
494
+
495
+ Explanation
496
+ ===========
497
+
498
+ Although the order is canonical from multiset_partitions, this is
499
+ not necessarily the best order to process the terms. For example,
500
+ if the case of len(gs) == 2 is removed and multiset is allowed to
501
+ sort the terms, some tests fail.
502
+
503
+ Examples
504
+ ========
505
+
506
+ >>> from sympy.integrals.meijerint import _mul_as_two_parts
507
+ >>> from sympy import sin, exp, ordered
508
+ >>> from sympy.abc import x
509
+ >>> list(ordered(_mul_as_two_parts(x*sin(x)*exp(x))))
510
+ [(x, exp(x)*sin(x)), (x*exp(x), sin(x)), (x*sin(x), exp(x))]
511
+ """
512
+
513
+ gs = _mul_args(f)
514
+ if len(gs) < 2:
515
+ return None
516
+ if len(gs) == 2:
517
+ return [tuple(gs)]
518
+ return [(Mul(*x), Mul(*y)) for (x, y) in multiset_partitions(gs, 2)]
519
+
520
+
521
+ def _inflate_g(g, n):
522
+ """ Return C, h such that h is a G function of argument z**n and
523
+ g = C*h. """
524
+ # TODO should this be a method of meijerg?
525
+ # See: [L, page 150, equation (5)]
526
+ def inflate(params, n):
527
+ """ (a1, .., ak) -> (a1/n, (a1+1)/n, ..., (ak + n-1)/n) """
528
+ return [(a + i)/n for a, i in itertools.product(params, range(n))]
529
+ v = S(len(g.ap) - len(g.bq))
530
+ C = n**(1 + g.nu + v/2)
531
+ C /= (2*pi)**((n - 1)*g.delta)
532
+ return C, meijerg(inflate(g.an, n), inflate(g.aother, n),
533
+ inflate(g.bm, n), inflate(g.bother, n),
534
+ g.argument**n * n**(n*v))
535
+
536
+
537
+ def _flip_g(g):
538
+ """ Turn the G function into one of inverse argument
539
+ (i.e. G(1/x) -> G'(x)) """
540
+ # See [L], section 5.2
541
+ def tr(l):
542
+ return [1 - a for a in l]
543
+ return meijerg(tr(g.bm), tr(g.bother), tr(g.an), tr(g.aother), 1/g.argument)
544
+
545
+
546
+ def _inflate_fox_h(g, a):
547
+ r"""
548
+ Let d denote the integrand in the definition of the G function ``g``.
549
+ Consider the function H which is defined in the same way, but with
550
+ integrand d/Gamma(a*s) (contour conventions as usual).
551
+
552
+ If ``a`` is rational, the function H can be written as C*G, for a constant C
553
+ and a G-function G.
554
+
555
+ This function returns C, G.
556
+ """
557
+ if a < 0:
558
+ return _inflate_fox_h(_flip_g(g), -a)
559
+ p = S(a.p)
560
+ q = S(a.q)
561
+ # We use the substitution s->qs, i.e. inflate g by q. We are left with an
562
+ # extra factor of Gamma(p*s), for which we use Gauss' multiplication
563
+ # theorem.
564
+ D, g = _inflate_g(g, q)
565
+ z = g.argument
566
+ D /= (2*pi)**((1 - p)/2)*p**Rational(-1, 2)
567
+ z /= p**p
568
+ bs = [(n + 1)/p for n in range(p)]
569
+ return D, meijerg(g.an, g.aother, g.bm, list(g.bother) + bs, z)
570
+
571
+
572
+ _dummies: dict[tuple[str, str], Dummy] = {}
573
+
574
+
575
+ def _dummy(name, token, expr, **kwargs):
576
+ """
577
+ Return a dummy. This will return the same dummy if the same token+name is
578
+ requested more than once, and it is not already in expr.
579
+ This is for being cache-friendly.
580
+ """
581
+ d = _dummy_(name, token, **kwargs)
582
+ if d in expr.free_symbols:
583
+ return Dummy(name, **kwargs)
584
+ return d
585
+
586
+
587
+ def _dummy_(name, token, **kwargs):
588
+ """
589
+ Return a dummy associated to name and token. Same effect as declaring
590
+ it globally.
591
+ """
592
+ if not (name, token) in _dummies:
593
+ _dummies[(name, token)] = Dummy(name, **kwargs)
594
+ return _dummies[(name, token)]
595
+
596
+
597
+ def _is_analytic(f, x):
598
+ """ Check if f(x), when expressed using G functions on the positive reals,
599
+ will in fact agree with the G functions almost everywhere """
600
+ return not any(x in expr.free_symbols for expr in f.atoms(Heaviside, Abs))
601
+
602
+
603
+ def _condsimp(cond, first=True):
604
+ """
605
+ Do naive simplifications on ``cond``.
606
+
607
+ Explanation
608
+ ===========
609
+
610
+ Note that this routine is completely ad-hoc, simplification rules being
611
+ added as need arises rather than following any logical pattern.
612
+
613
+ Examples
614
+ ========
615
+
616
+ >>> from sympy.integrals.meijerint import _condsimp as simp
617
+ >>> from sympy import Or, Eq
618
+ >>> from sympy.abc import x, y
619
+ >>> simp(Or(x < y, Eq(x, y)))
620
+ x <= y
621
+ """
622
+ if first:
623
+ cond = cond.replace(lambda _: _.is_Relational, _canonical_coeff)
624
+ first = False
625
+ if not isinstance(cond, BooleanFunction):
626
+ return cond
627
+ p, q, r = symbols('p q r', cls=Wild)
628
+ # transforms tests use 0, 4, 5 and 11-14
629
+ # meijer tests use 0, 2, 11, 14
630
+ # joint_rv uses 6, 7
631
+ rules = [
632
+ (Or(p < q, Eq(p, q)), p <= q), # 0
633
+ # The next two obviously are instances of a general pattern, but it is
634
+ # easier to spell out the few cases we care about.
635
+ (And(Abs(arg(p)) <= pi, Abs(arg(p) - 2*pi) <= pi),
636
+ Eq(arg(p) - pi, 0)), # 1
637
+ (And(Abs(2*arg(p) + pi) <= pi, Abs(2*arg(p) - pi) <= pi),
638
+ Eq(arg(p), 0)), # 2
639
+ (And(Abs(2*arg(p) + pi) < pi, Abs(2*arg(p) - pi) <= pi),
640
+ S.false), # 3
641
+ (And(Abs(arg(p) - pi/2) <= pi/2, Abs(arg(p) + pi/2) <= pi/2),
642
+ Eq(arg(p), 0)), # 4
643
+ (And(Abs(arg(p) - pi/2) <= pi/2, Abs(arg(p) + pi/2) < pi/2),
644
+ S.false), # 5
645
+ (And(Abs(arg(p**2/2 + 1)) < pi, Ne(Abs(arg(p**2/2 + 1)), pi)),
646
+ S.true), # 6
647
+ (Or(Abs(arg(p**2/2 + 1)) < pi, Ne(1/(p**2/2 + 1), 0)),
648
+ S.true), # 7
649
+ (And(Abs(unbranched_argument(p)) <= pi,
650
+ Abs(unbranched_argument(exp_polar(-2*pi*S.ImaginaryUnit)*p)) <= pi),
651
+ Eq(unbranched_argument(exp_polar(-S.ImaginaryUnit*pi)*p), 0)), # 8
652
+ (And(Abs(unbranched_argument(p)) <= pi/2,
653
+ Abs(unbranched_argument(exp_polar(-pi*S.ImaginaryUnit)*p)) <= pi/2),
654
+ Eq(unbranched_argument(exp_polar(-S.ImaginaryUnit*pi/2)*p), 0)), # 9
655
+ (Or(p <= q, And(p < q, r)), p <= q), # 10
656
+ (Ne(p**2, 1) & (p**2 > 1), p**2 > 1), # 11
657
+ (Ne(1/p, 1) & (cos(Abs(arg(p)))*Abs(p) > 1), Abs(p) > 1), # 12
658
+ (Ne(p, 2) & (cos(Abs(arg(p)))*Abs(p) > 2), Abs(p) > 2), # 13
659
+ ((Abs(arg(p)) < pi/2) & (cos(Abs(arg(p)))*sqrt(Abs(p**2)) > 1), p**2 > 1), # 14
660
+ ]
661
+ cond = cond.func(*[_condsimp(_, first) for _ in cond.args])
662
+ change = True
663
+ while change:
664
+ change = False
665
+ for irule, (fro, to) in enumerate(rules):
666
+ if fro.func != cond.func:
667
+ continue
668
+ for n, arg1 in enumerate(cond.args):
669
+ if r in fro.args[0].free_symbols:
670
+ m = arg1.match(fro.args[1])
671
+ num = 1
672
+ else:
673
+ num = 0
674
+ m = arg1.match(fro.args[0])
675
+ if not m:
676
+ continue
677
+ otherargs = [x.subs(m) for x in fro.args[:num] + fro.args[num + 1:]]
678
+ otherlist = [n]
679
+ for arg2 in otherargs:
680
+ for k, arg3 in enumerate(cond.args):
681
+ if k in otherlist:
682
+ continue
683
+ if arg2 == arg3:
684
+ otherlist += [k]
685
+ break
686
+ if isinstance(arg3, And) and arg2.args[1] == r and \
687
+ isinstance(arg2, And) and arg2.args[0] in arg3.args:
688
+ otherlist += [k]
689
+ break
690
+ if isinstance(arg3, And) and arg2.args[0] == r and \
691
+ isinstance(arg2, And) and arg2.args[1] in arg3.args:
692
+ otherlist += [k]
693
+ break
694
+ if len(otherlist) != len(otherargs) + 1:
695
+ continue
696
+ newargs = [arg_ for (k, arg_) in enumerate(cond.args)
697
+ if k not in otherlist] + [to.subs(m)]
698
+ if SYMPY_DEBUG:
699
+ if irule not in (0, 2, 4, 5, 6, 7, 11, 12, 13, 14):
700
+ print('used new rule:', irule)
701
+ cond = cond.func(*newargs)
702
+ change = True
703
+ break
704
+
705
+ # final tweak
706
+ def rel_touchup(rel):
707
+ if rel.rel_op != '==' or rel.rhs != 0:
708
+ return rel
709
+
710
+ # handle Eq(*, 0)
711
+ LHS = rel.lhs
712
+ m = LHS.match(arg(p)**q)
713
+ if not m:
714
+ m = LHS.match(unbranched_argument(polar_lift(p)**q))
715
+ if not m:
716
+ if isinstance(LHS, periodic_argument) and not LHS.args[0].is_polar \
717
+ and LHS.args[1] is S.Infinity:
718
+ return (LHS.args[0] > 0)
719
+ return rel
720
+ return (m[p] > 0)
721
+ cond = cond.replace(lambda _: _.is_Relational, rel_touchup)
722
+ if SYMPY_DEBUG:
723
+ print('_condsimp: ', cond)
724
+ return cond
725
+
726
+ def _eval_cond(cond):
727
+ """ Re-evaluate the conditions. """
728
+ if isinstance(cond, bool):
729
+ return cond
730
+ return _condsimp(cond.doit())
731
+
732
+ ####################################################################
733
+ # Now the "backbone" functions to do actual integration.
734
+ ####################################################################
735
+
736
+
737
+ def _my_principal_branch(expr, period, full_pb=False):
738
+ """ Bring expr nearer to its principal branch by removing superfluous
739
+ factors.
740
+ This function does *not* guarantee to yield the principal branch,
741
+ to avoid introducing opaque principal_branch() objects,
742
+ unless full_pb=True. """
743
+ res = principal_branch(expr, period)
744
+ if not full_pb:
745
+ res = res.replace(principal_branch, lambda x, y: x)
746
+ return res
747
+
748
+
749
+ def _rewrite_saxena_1(fac, po, g, x):
750
+ """
751
+ Rewrite the integral fac*po*g dx, from zero to infinity, as
752
+ integral fac*G, where G has argument a*x. Note po=x**s.
753
+ Return fac, G.
754
+ """
755
+ _, s = _get_coeff_exp(po, x)
756
+ a, b = _get_coeff_exp(g.argument, x)
757
+ period = g.get_period()
758
+ a = _my_principal_branch(a, period)
759
+
760
+ # We substitute t = x**b.
761
+ C = fac/(Abs(b)*a**((s + 1)/b - 1))
762
+ # Absorb a factor of (at)**((1 + s)/b - 1).
763
+
764
+ def tr(l):
765
+ return [a + (1 + s)/b - 1 for a in l]
766
+ return C, meijerg(tr(g.an), tr(g.aother), tr(g.bm), tr(g.bother),
767
+ a*x)
768
+
769
+
770
+ def _check_antecedents_1(g, x, helper=False):
771
+ r"""
772
+ Return a condition under which the mellin transform of g exists.
773
+ Any power of x has already been absorbed into the G function,
774
+ so this is just $\int_0^\infty g\, dx$.
775
+
776
+ See [L, section 5.6.1]. (Note that s=1.)
777
+
778
+ If ``helper`` is True, only check if the MT exists at infinity, i.e. if
779
+ $\int_1^\infty g\, dx$ exists.
780
+ """
781
+ # NOTE if you update these conditions, please update the documentation as well
782
+ delta = g.delta
783
+ eta, _ = _get_coeff_exp(g.argument, x)
784
+ m, n, p, q = S([len(g.bm), len(g.an), len(g.ap), len(g.bq)])
785
+
786
+ if p > q:
787
+ def tr(l):
788
+ return [1 - x for x in l]
789
+ return _check_antecedents_1(meijerg(tr(g.bm), tr(g.bother),
790
+ tr(g.an), tr(g.aother), x/eta),
791
+ x)
792
+
793
+ tmp = [-re(b) < 1 for b in g.bm] + [1 < 1 - re(a) for a in g.an]
794
+ cond_3 = And(*tmp)
795
+
796
+ tmp += [-re(b) < 1 for b in g.bother]
797
+ tmp += [1 < 1 - re(a) for a in g.aother]
798
+ cond_3_star = And(*tmp)
799
+
800
+ cond_4 = (-re(g.nu) + (q + 1 - p)/2 > q - p)
801
+
802
+ def debug(*msg):
803
+ _debug(*msg)
804
+
805
+ def debugf(string, arg):
806
+ _debugf(string, arg)
807
+
808
+ debug('Checking antecedents for 1 function:')
809
+ debugf(' delta=%s, eta=%s, m=%s, n=%s, p=%s, q=%s',
810
+ (delta, eta, m, n, p, q))
811
+ debugf(' ap = %s, %s', (list(g.an), list(g.aother)))
812
+ debugf(' bq = %s, %s', (list(g.bm), list(g.bother)))
813
+ debugf(' cond_3=%s, cond_3*=%s, cond_4=%s', (cond_3, cond_3_star, cond_4))
814
+
815
+ conds = []
816
+
817
+ # case 1
818
+ case1 = []
819
+ tmp1 = [1 <= n, p < q, 1 <= m]
820
+ tmp2 = [1 <= p, 1 <= m, Eq(q, p + 1), Not(And(Eq(n, 0), Eq(m, p + 1)))]
821
+ tmp3 = [1 <= p, Eq(q, p)]
822
+ for k in range(ceiling(delta/2) + 1):
823
+ tmp3 += [Ne(Abs(unbranched_argument(eta)), (delta - 2*k)*pi)]
824
+ tmp = [delta > 0, Abs(unbranched_argument(eta)) < delta*pi]
825
+ extra = [Ne(eta, 0), cond_3]
826
+ if helper:
827
+ extra = []
828
+ for t in [tmp1, tmp2, tmp3]:
829
+ case1 += [And(*(t + tmp + extra))]
830
+ conds += case1
831
+ debug(' case 1:', case1)
832
+
833
+ # case 2
834
+ extra = [cond_3]
835
+ if helper:
836
+ extra = []
837
+ case2 = [And(Eq(n, 0), p + 1 <= m, m <= q,
838
+ Abs(unbranched_argument(eta)) < delta*pi, *extra)]
839
+ conds += case2
840
+ debug(' case 2:', case2)
841
+
842
+ # case 3
843
+ extra = [cond_3, cond_4]
844
+ if helper:
845
+ extra = []
846
+ case3 = [And(p < q, 1 <= m, delta > 0, Eq(Abs(unbranched_argument(eta)), delta*pi),
847
+ *extra)]
848
+ case3 += [And(p <= q - 2, Eq(delta, 0), Eq(Abs(unbranched_argument(eta)), 0), *extra)]
849
+ conds += case3
850
+ debug(' case 3:', case3)
851
+
852
+ # TODO altered cases 4-7
853
+
854
+ # extra case from wofram functions site:
855
+ # (reproduced verbatim from Prudnikov, section 2.24.2)
856
+ # https://functions.wolfram.com/HypergeometricFunctions/MeijerG/21/02/01/
857
+ case_extra = []
858
+ case_extra += [Eq(p, q), Eq(delta, 0), Eq(unbranched_argument(eta), 0), Ne(eta, 0)]
859
+ if not helper:
860
+ case_extra += [cond_3]
861
+ s = []
862
+ for a, b in zip(g.ap, g.bq):
863
+ s += [b - a]
864
+ case_extra += [re(Add(*s)) < 0]
865
+ case_extra = And(*case_extra)
866
+ conds += [case_extra]
867
+ debug(' extra case:', [case_extra])
868
+
869
+ case_extra_2 = [And(delta > 0, Abs(unbranched_argument(eta)) < delta*pi)]
870
+ if not helper:
871
+ case_extra_2 += [cond_3]
872
+ case_extra_2 = And(*case_extra_2)
873
+ conds += [case_extra_2]
874
+ debug(' second extra case:', [case_extra_2])
875
+
876
+ # TODO This leaves only one case from the three listed by Prudnikov.
877
+ # Investigate if these indeed cover everything; if so, remove the rest.
878
+
879
+ return Or(*conds)
880
+
881
+
882
+ def _int0oo_1(g, x):
883
+ r"""
884
+ Evaluate $\int_0^\infty g\, dx$ using G functions,
885
+ assuming the necessary conditions are fulfilled.
886
+
887
+ Examples
888
+ ========
889
+
890
+ >>> from sympy.abc import a, b, c, d, x, y
891
+ >>> from sympy import meijerg
892
+ >>> from sympy.integrals.meijerint import _int0oo_1
893
+ >>> _int0oo_1(meijerg([a], [b], [c], [d], x*y), x)
894
+ gamma(-a)*gamma(c + 1)/(y*gamma(-d)*gamma(b + 1))
895
+ """
896
+ from sympy.simplify import gammasimp
897
+ # See [L, section 5.6.1]. Note that s=1.
898
+ eta, _ = _get_coeff_exp(g.argument, x)
899
+ res = 1/eta
900
+ # XXX TODO we should reduce order first
901
+ for b in g.bm:
902
+ res *= gamma(b + 1)
903
+ for a in g.an:
904
+ res *= gamma(1 - a - 1)
905
+ for b in g.bother:
906
+ res /= gamma(1 - b - 1)
907
+ for a in g.aother:
908
+ res /= gamma(a + 1)
909
+ return gammasimp(unpolarify(res))
910
+
911
+
912
+ def _rewrite_saxena(fac, po, g1, g2, x, full_pb=False):
913
+ """
914
+ Rewrite the integral ``fac*po*g1*g2`` from 0 to oo in terms of G
915
+ functions with argument ``c*x``.
916
+
917
+ Explanation
918
+ ===========
919
+
920
+ Return C, f1, f2 such that integral C f1 f2 from 0 to infinity equals
921
+ integral fac ``po``, ``g1``, ``g2`` from 0 to infinity.
922
+
923
+ Examples
924
+ ========
925
+
926
+ >>> from sympy.integrals.meijerint import _rewrite_saxena
927
+ >>> from sympy.abc import s, t, m
928
+ >>> from sympy import meijerg
929
+ >>> g1 = meijerg([], [], [0], [], s*t)
930
+ >>> g2 = meijerg([], [], [m/2], [-m/2], t**2/4)
931
+ >>> r = _rewrite_saxena(1, t**0, g1, g2, t)
932
+ >>> r[0]
933
+ s/(4*sqrt(pi))
934
+ >>> r[1]
935
+ meijerg(((), ()), ((-1/2, 0), ()), s**2*t/4)
936
+ >>> r[2]
937
+ meijerg(((), ()), ((m/2,), (-m/2,)), t/4)
938
+ """
939
+ def pb(g):
940
+ a, b = _get_coeff_exp(g.argument, x)
941
+ per = g.get_period()
942
+ return meijerg(g.an, g.aother, g.bm, g.bother,
943
+ _my_principal_branch(a, per, full_pb)*x**b)
944
+
945
+ _, s = _get_coeff_exp(po, x)
946
+ _, b1 = _get_coeff_exp(g1.argument, x)
947
+ _, b2 = _get_coeff_exp(g2.argument, x)
948
+ if (b1 < 0) == True:
949
+ b1 = -b1
950
+ g1 = _flip_g(g1)
951
+ if (b2 < 0) == True:
952
+ b2 = -b2
953
+ g2 = _flip_g(g2)
954
+ if not b1.is_Rational or not b2.is_Rational:
955
+ return
956
+ m1, n1 = b1.p, b1.q
957
+ m2, n2 = b2.p, b2.q
958
+ tau = ilcm(m1*n2, m2*n1)
959
+ r1 = tau//(m1*n2)
960
+ r2 = tau//(m2*n1)
961
+
962
+ C1, g1 = _inflate_g(g1, r1)
963
+ C2, g2 = _inflate_g(g2, r2)
964
+ g1 = pb(g1)
965
+ g2 = pb(g2)
966
+
967
+ fac *= C1*C2
968
+ a1, b = _get_coeff_exp(g1.argument, x)
969
+ a2, _ = _get_coeff_exp(g2.argument, x)
970
+
971
+ # arbitrarily tack on the x**s part to g1
972
+ # TODO should we try both?
973
+ exp = (s + 1)/b - 1
974
+ fac = fac/(Abs(b) * a1**exp)
975
+
976
+ def tr(l):
977
+ return [a + exp for a in l]
978
+ g1 = meijerg(tr(g1.an), tr(g1.aother), tr(g1.bm), tr(g1.bother), a1*x)
979
+ g2 = meijerg(g2.an, g2.aother, g2.bm, g2.bother, a2*x)
980
+
981
+ from sympy.simplify import powdenest
982
+ return powdenest(fac, polar=True), g1, g2
983
+
984
+
985
+ def _check_antecedents(g1, g2, x):
986
+ """ Return a condition under which the integral theorem applies. """
987
+ # Yes, this is madness.
988
+ # XXX TODO this is a testing *nightmare*
989
+ # NOTE if you update these conditions, please update the documentation as well
990
+
991
+ # The following conditions are found in
992
+ # [P], Section 2.24.1
993
+ #
994
+ # They are also reproduced (verbatim!) at
995
+ # https://functions.wolfram.com/HypergeometricFunctions/MeijerG/21/02/03/
996
+ #
997
+ # Note: k=l=r=alpha=1
998
+ sigma, _ = _get_coeff_exp(g1.argument, x)
999
+ omega, _ = _get_coeff_exp(g2.argument, x)
1000
+ s, t, u, v = S([len(g1.bm), len(g1.an), len(g1.ap), len(g1.bq)])
1001
+ m, n, p, q = S([len(g2.bm), len(g2.an), len(g2.ap), len(g2.bq)])
1002
+ bstar = s + t - (u + v)/2
1003
+ cstar = m + n - (p + q)/2
1004
+ rho = g1.nu + (u - v)/2 + 1
1005
+ mu = g2.nu + (p - q)/2 + 1
1006
+ phi = q - p - (v - u)
1007
+ eta = 1 - (v - u) - mu - rho
1008
+ psi = (pi*(q - m - n) + Abs(unbranched_argument(omega)))/(q - p)
1009
+ theta = (pi*(v - s - t) + Abs(unbranched_argument(sigma)))/(v - u)
1010
+
1011
+ _debug('Checking antecedents:')
1012
+ _debugf(' sigma=%s, s=%s, t=%s, u=%s, v=%s, b*=%s, rho=%s',
1013
+ (sigma, s, t, u, v, bstar, rho))
1014
+ _debugf(' omega=%s, m=%s, n=%s, p=%s, q=%s, c*=%s, mu=%s,',
1015
+ (omega, m, n, p, q, cstar, mu))
1016
+ _debugf(' phi=%s, eta=%s, psi=%s, theta=%s', (phi, eta, psi, theta))
1017
+
1018
+ def _c1():
1019
+ for g in [g1, g2]:
1020
+ for i, j in itertools.product(g.an, g.bm):
1021
+ diff = i - j
1022
+ if diff.is_integer and diff.is_positive:
1023
+ return False
1024
+ return True
1025
+ c1 = _c1()
1026
+ c2 = And(*[re(1 + i + j) > 0 for i in g1.bm for j in g2.bm])
1027
+ c3 = And(*[re(1 + i + j) < 1 + 1 for i in g1.an for j in g2.an])
1028
+ c4 = And(*[(p - q)*re(1 + i - 1) - re(mu) > Rational(-3, 2) for i in g1.an])
1029
+ c5 = And(*[(p - q)*re(1 + i) - re(mu) > Rational(-3, 2) for i in g1.bm])
1030
+ c6 = And(*[(u - v)*re(1 + i - 1) - re(rho) > Rational(-3, 2) for i in g2.an])
1031
+ c7 = And(*[(u - v)*re(1 + i) - re(rho) > Rational(-3, 2) for i in g2.bm])
1032
+ c8 = (Abs(phi) + 2*re((rho - 1)*(q - p) + (v - u)*(q - p) + (mu -
1033
+ 1)*(v - u)) > 0)
1034
+ c9 = (Abs(phi) - 2*re((rho - 1)*(q - p) + (v - u)*(q - p) + (mu -
1035
+ 1)*(v - u)) > 0)
1036
+ c10 = (Abs(unbranched_argument(sigma)) < bstar*pi)
1037
+ c11 = Eq(Abs(unbranched_argument(sigma)), bstar*pi)
1038
+ c12 = (Abs(unbranched_argument(omega)) < cstar*pi)
1039
+ c13 = Eq(Abs(unbranched_argument(omega)), cstar*pi)
1040
+
1041
+ # The following condition is *not* implemented as stated on the wolfram
1042
+ # function site. In the book of Prudnikov there is an additional part
1043
+ # (the And involving re()). However, I only have this book in russian, and
1044
+ # I don't read any russian. The following condition is what other people
1045
+ # have told me it means.
1046
+ # Worryingly, it is different from the condition implemented in REDUCE.
1047
+ # The REDUCE implementation:
1048
+ # https://reduce-algebra.svn.sourceforge.net/svnroot/reduce-algebra/trunk/packages/defint/definta.red
1049
+ # (search for tst14)
1050
+ # The Wolfram alpha version:
1051
+ # https://functions.wolfram.com/HypergeometricFunctions/MeijerG/21/02/03/03/0014/
1052
+ z0 = exp(-(bstar + cstar)*pi*S.ImaginaryUnit)
1053
+ zos = unpolarify(z0*omega/sigma)
1054
+ zso = unpolarify(z0*sigma/omega)
1055
+ if zos == 1/zso:
1056
+ c14 = And(Eq(phi, 0), bstar + cstar <= 1,
1057
+ Or(Ne(zos, 1), re(mu + rho + v - u) < 1,
1058
+ re(mu + rho + q - p) < 1))
1059
+ else:
1060
+ def _cond(z):
1061
+ '''Returns True if abs(arg(1-z)) < pi, avoiding arg(0).
1062
+
1063
+ Explanation
1064
+ ===========
1065
+
1066
+ If ``z`` is 1 then arg is NaN. This raises a
1067
+ TypeError on `NaN < pi`. Previously this gave `False` so
1068
+ this behavior has been hardcoded here but someone should
1069
+ check if this NaN is more serious! This NaN is triggered by
1070
+ test_meijerint() in test_meijerint.py:
1071
+ `meijerint_definite(exp(x), x, 0, I)`
1072
+ '''
1073
+ return z != 1 and Abs(arg(1 - z)) < pi
1074
+
1075
+ c14 = And(Eq(phi, 0), bstar - 1 + cstar <= 0,
1076
+ Or(And(Ne(zos, 1), _cond(zos)),
1077
+ And(re(mu + rho + v - u) < 1, Eq(zos, 1))))
1078
+
1079
+ c14_alt = And(Eq(phi, 0), cstar - 1 + bstar <= 0,
1080
+ Or(And(Ne(zso, 1), _cond(zso)),
1081
+ And(re(mu + rho + q - p) < 1, Eq(zso, 1))))
1082
+
1083
+ # Since r=k=l=1, in our case there is c14_alt which is the same as calling
1084
+ # us with (g1, g2) = (g2, g1). The conditions below enumerate all cases
1085
+ # (i.e. we don't have to try arguments reversed by hand), and indeed try
1086
+ # all symmetric cases. (i.e. whenever there is a condition involving c14,
1087
+ # there is also a dual condition which is exactly what we would get when g1,
1088
+ # g2 were interchanged, *but c14 was unaltered*).
1089
+ # Hence the following seems correct:
1090
+ c14 = Or(c14, c14_alt)
1091
+
1092
+ '''
1093
+ When `c15` is NaN (e.g. from `psi` being NaN as happens during
1094
+ 'test_issue_4992' and/or `theta` is NaN as in 'test_issue_6253',
1095
+ both in `test_integrals.py`) the comparison to 0 formerly gave False
1096
+ whereas now an error is raised. To keep the old behavior, the value
1097
+ of NaN is replaced with False but perhaps a closer look at this condition
1098
+ should be made: XXX how should conditions leading to c15=NaN be handled?
1099
+ '''
1100
+ try:
1101
+ lambda_c = (q - p)*Abs(omega)**(1/(q - p))*cos(psi) \
1102
+ + (v - u)*Abs(sigma)**(1/(v - u))*cos(theta)
1103
+ # the TypeError might be raised here, e.g. if lambda_c is NaN
1104
+ if _eval_cond(lambda_c > 0) != False:
1105
+ c15 = (lambda_c > 0)
1106
+ else:
1107
+ def lambda_s0(c1, c2):
1108
+ return c1*(q - p)*Abs(omega)**(1/(q - p))*sin(psi) \
1109
+ + c2*(v - u)*Abs(sigma)**(1/(v - u))*sin(theta)
1110
+ lambda_s = Piecewise(
1111
+ ((lambda_s0(+1, +1)*lambda_s0(-1, -1)),
1112
+ And(Eq(unbranched_argument(sigma), 0), Eq(unbranched_argument(omega), 0))),
1113
+ (lambda_s0(sign(unbranched_argument(omega)), +1)*lambda_s0(sign(unbranched_argument(omega)), -1),
1114
+ And(Eq(unbranched_argument(sigma), 0), Ne(unbranched_argument(omega), 0))),
1115
+ (lambda_s0(+1, sign(unbranched_argument(sigma)))*lambda_s0(-1, sign(unbranched_argument(sigma))),
1116
+ And(Ne(unbranched_argument(sigma), 0), Eq(unbranched_argument(omega), 0))),
1117
+ (lambda_s0(sign(unbranched_argument(omega)), sign(unbranched_argument(sigma))), True))
1118
+ tmp = [lambda_c > 0,
1119
+ And(Eq(lambda_c, 0), Ne(lambda_s, 0), re(eta) > -1),
1120
+ And(Eq(lambda_c, 0), Eq(lambda_s, 0), re(eta) > 0)]
1121
+ c15 = Or(*tmp)
1122
+ except TypeError:
1123
+ c15 = False
1124
+ for cond, i in [(c1, 1), (c2, 2), (c3, 3), (c4, 4), (c5, 5), (c6, 6),
1125
+ (c7, 7), (c8, 8), (c9, 9), (c10, 10), (c11, 11),
1126
+ (c12, 12), (c13, 13), (c14, 14), (c15, 15)]:
1127
+ _debugf(' c%s: %s', (i, cond))
1128
+
1129
+ # We will return Or(*conds)
1130
+ conds = []
1131
+
1132
+ def pr(count):
1133
+ _debugf(' case %s: %s', (count, conds[-1]))
1134
+ conds += [And(m*n*s*t != 0, bstar.is_positive is True, cstar.is_positive is True, c1, c2, c3, c10,
1135
+ c12)] # 1
1136
+ pr(1)
1137
+ conds += [And(Eq(u, v), Eq(bstar, 0), cstar.is_positive is True, sigma.is_positive is True, re(rho) < 1,
1138
+ c1, c2, c3, c12)] # 2
1139
+ pr(2)
1140
+ conds += [And(Eq(p, q), Eq(cstar, 0), bstar.is_positive is True, omega.is_positive is True, re(mu) < 1,
1141
+ c1, c2, c3, c10)] # 3
1142
+ pr(3)
1143
+ conds += [And(Eq(p, q), Eq(u, v), Eq(bstar, 0), Eq(cstar, 0),
1144
+ sigma.is_positive is True, omega.is_positive is True, re(mu) < 1, re(rho) < 1,
1145
+ Ne(sigma, omega), c1, c2, c3)] # 4
1146
+ pr(4)
1147
+ conds += [And(Eq(p, q), Eq(u, v), Eq(bstar, 0), Eq(cstar, 0),
1148
+ sigma.is_positive is True, omega.is_positive is True, re(mu + rho) < 1,
1149
+ Ne(omega, sigma), c1, c2, c3)] # 5
1150
+ pr(5)
1151
+ conds += [And(p > q, s.is_positive is True, bstar.is_positive is True, cstar >= 0,
1152
+ c1, c2, c3, c5, c10, c13)] # 6
1153
+ pr(6)
1154
+ conds += [And(p < q, t.is_positive is True, bstar.is_positive is True, cstar >= 0,
1155
+ c1, c2, c3, c4, c10, c13)] # 7
1156
+ pr(7)
1157
+ conds += [And(u > v, m.is_positive is True, cstar.is_positive is True, bstar >= 0,
1158
+ c1, c2, c3, c7, c11, c12)] # 8
1159
+ pr(8)
1160
+ conds += [And(u < v, n.is_positive is True, cstar.is_positive is True, bstar >= 0,
1161
+ c1, c2, c3, c6, c11, c12)] # 9
1162
+ pr(9)
1163
+ conds += [And(p > q, Eq(u, v), Eq(bstar, 0), cstar >= 0, sigma.is_positive is True,
1164
+ re(rho) < 1, c1, c2, c3, c5, c13)] # 10
1165
+ pr(10)
1166
+ conds += [And(p < q, Eq(u, v), Eq(bstar, 0), cstar >= 0, sigma.is_positive is True,
1167
+ re(rho) < 1, c1, c2, c3, c4, c13)] # 11
1168
+ pr(11)
1169
+ conds += [And(Eq(p, q), u > v, bstar >= 0, Eq(cstar, 0), omega.is_positive is True,
1170
+ re(mu) < 1, c1, c2, c3, c7, c11)] # 12
1171
+ pr(12)
1172
+ conds += [And(Eq(p, q), u < v, bstar >= 0, Eq(cstar, 0), omega.is_positive is True,
1173
+ re(mu) < 1, c1, c2, c3, c6, c11)] # 13
1174
+ pr(13)
1175
+ conds += [And(p < q, u > v, bstar >= 0, cstar >= 0,
1176
+ c1, c2, c3, c4, c7, c11, c13)] # 14
1177
+ pr(14)
1178
+ conds += [And(p > q, u < v, bstar >= 0, cstar >= 0,
1179
+ c1, c2, c3, c5, c6, c11, c13)] # 15
1180
+ pr(15)
1181
+ conds += [And(p > q, u > v, bstar >= 0, cstar >= 0,
1182
+ c1, c2, c3, c5, c7, c8, c11, c13, c14)] # 16
1183
+ pr(16)
1184
+ conds += [And(p < q, u < v, bstar >= 0, cstar >= 0,
1185
+ c1, c2, c3, c4, c6, c9, c11, c13, c14)] # 17
1186
+ pr(17)
1187
+ conds += [And(Eq(t, 0), s.is_positive is True, bstar.is_positive is True, phi.is_positive is True, c1, c2, c10)] # 18
1188
+ pr(18)
1189
+ conds += [And(Eq(s, 0), t.is_positive is True, bstar.is_positive is True, phi.is_negative is True, c1, c3, c10)] # 19
1190
+ pr(19)
1191
+ conds += [And(Eq(n, 0), m.is_positive is True, cstar.is_positive is True, phi.is_negative is True, c1, c2, c12)] # 20
1192
+ pr(20)
1193
+ conds += [And(Eq(m, 0), n.is_positive is True, cstar.is_positive is True, phi.is_positive is True, c1, c3, c12)] # 21
1194
+ pr(21)
1195
+ conds += [And(Eq(s*t, 0), bstar.is_positive is True, cstar.is_positive is True,
1196
+ c1, c2, c3, c10, c12)] # 22
1197
+ pr(22)
1198
+ conds += [And(Eq(m*n, 0), bstar.is_positive is True, cstar.is_positive is True,
1199
+ c1, c2, c3, c10, c12)] # 23
1200
+ pr(23)
1201
+
1202
+ # The following case is from [Luke1969]. As far as I can tell, it is *not*
1203
+ # covered by Prudnikov's.
1204
+ # Let G1 and G2 be the two G-functions. Suppose the integral exists from
1205
+ # 0 to a > 0 (this is easy the easy part), that G1 is exponential decay at
1206
+ # infinity, and that the mellin transform of G2 exists.
1207
+ # Then the integral exists.
1208
+ mt1_exists = _check_antecedents_1(g1, x, helper=True)
1209
+ mt2_exists = _check_antecedents_1(g2, x, helper=True)
1210
+ conds += [And(mt2_exists, Eq(t, 0), u < s, bstar.is_positive is True, c10, c1, c2, c3)]
1211
+ pr('E1')
1212
+ conds += [And(mt2_exists, Eq(s, 0), v < t, bstar.is_positive is True, c10, c1, c2, c3)]
1213
+ pr('E2')
1214
+ conds += [And(mt1_exists, Eq(n, 0), p < m, cstar.is_positive is True, c12, c1, c2, c3)]
1215
+ pr('E3')
1216
+ conds += [And(mt1_exists, Eq(m, 0), q < n, cstar.is_positive is True, c12, c1, c2, c3)]
1217
+ pr('E4')
1218
+
1219
+ # Let's short-circuit if this worked ...
1220
+ # the rest is corner-cases and terrible to read.
1221
+ r = Or(*conds)
1222
+ if _eval_cond(r) != False:
1223
+ return r
1224
+
1225
+ conds += [And(m + n > p, Eq(t, 0), Eq(phi, 0), s.is_positive is True, bstar.is_positive is True, cstar.is_negative is True,
1226
+ Abs(unbranched_argument(omega)) < (m + n - p + 1)*pi,
1227
+ c1, c2, c10, c14, c15)] # 24
1228
+ pr(24)
1229
+ conds += [And(m + n > q, Eq(s, 0), Eq(phi, 0), t.is_positive is True, bstar.is_positive is True, cstar.is_negative is True,
1230
+ Abs(unbranched_argument(omega)) < (m + n - q + 1)*pi,
1231
+ c1, c3, c10, c14, c15)] # 25
1232
+ pr(25)
1233
+ conds += [And(Eq(p, q - 1), Eq(t, 0), Eq(phi, 0), s.is_positive is True, bstar.is_positive is True,
1234
+ cstar >= 0, cstar*pi < Abs(unbranched_argument(omega)),
1235
+ c1, c2, c10, c14, c15)] # 26
1236
+ pr(26)
1237
+ conds += [And(Eq(p, q + 1), Eq(s, 0), Eq(phi, 0), t.is_positive is True, bstar.is_positive is True,
1238
+ cstar >= 0, cstar*pi < Abs(unbranched_argument(omega)),
1239
+ c1, c3, c10, c14, c15)] # 27
1240
+ pr(27)
1241
+ conds += [And(p < q - 1, Eq(t, 0), Eq(phi, 0), s.is_positive is True, bstar.is_positive is True,
1242
+ cstar >= 0, cstar*pi < Abs(unbranched_argument(omega)),
1243
+ Abs(unbranched_argument(omega)) < (m + n - p + 1)*pi,
1244
+ c1, c2, c10, c14, c15)] # 28
1245
+ pr(28)
1246
+ conds += [And(
1247
+ p > q + 1, Eq(s, 0), Eq(phi, 0), t.is_positive is True, bstar.is_positive is True, cstar >= 0,
1248
+ cstar*pi < Abs(unbranched_argument(omega)),
1249
+ Abs(unbranched_argument(omega)) < (m + n - q + 1)*pi,
1250
+ c1, c3, c10, c14, c15)] # 29
1251
+ pr(29)
1252
+ conds += [And(Eq(n, 0), Eq(phi, 0), s + t > 0, m.is_positive is True, cstar.is_positive is True, bstar.is_negative is True,
1253
+ Abs(unbranched_argument(sigma)) < (s + t - u + 1)*pi,
1254
+ c1, c2, c12, c14, c15)] # 30
1255
+ pr(30)
1256
+ conds += [And(Eq(m, 0), Eq(phi, 0), s + t > v, n.is_positive is True, cstar.is_positive is True, bstar.is_negative is True,
1257
+ Abs(unbranched_argument(sigma)) < (s + t - v + 1)*pi,
1258
+ c1, c3, c12, c14, c15)] # 31
1259
+ pr(31)
1260
+ conds += [And(Eq(n, 0), Eq(phi, 0), Eq(u, v - 1), m.is_positive is True, cstar.is_positive is True,
1261
+ bstar >= 0, bstar*pi < Abs(unbranched_argument(sigma)),
1262
+ Abs(unbranched_argument(sigma)) < (bstar + 1)*pi,
1263
+ c1, c2, c12, c14, c15)] # 32
1264
+ pr(32)
1265
+ conds += [And(Eq(m, 0), Eq(phi, 0), Eq(u, v + 1), n.is_positive is True, cstar.is_positive is True,
1266
+ bstar >= 0, bstar*pi < Abs(unbranched_argument(sigma)),
1267
+ Abs(unbranched_argument(sigma)) < (bstar + 1)*pi,
1268
+ c1, c3, c12, c14, c15)] # 33
1269
+ pr(33)
1270
+ conds += [And(
1271
+ Eq(n, 0), Eq(phi, 0), u < v - 1, m.is_positive is True, cstar.is_positive is True, bstar >= 0,
1272
+ bstar*pi < Abs(unbranched_argument(sigma)),
1273
+ Abs(unbranched_argument(sigma)) < (s + t - u + 1)*pi,
1274
+ c1, c2, c12, c14, c15)] # 34
1275
+ pr(34)
1276
+ conds += [And(
1277
+ Eq(m, 0), Eq(phi, 0), u > v + 1, n.is_positive is True, cstar.is_positive is True, bstar >= 0,
1278
+ bstar*pi < Abs(unbranched_argument(sigma)),
1279
+ Abs(unbranched_argument(sigma)) < (s + t - v + 1)*pi,
1280
+ c1, c3, c12, c14, c15)] # 35
1281
+ pr(35)
1282
+
1283
+ return Or(*conds)
1284
+
1285
+ # NOTE An alternative, but as far as I can tell weaker, set of conditions
1286
+ # can be found in [L, section 5.6.2].
1287
+
1288
+
1289
+ def _int0oo(g1, g2, x):
1290
+ """
1291
+ Express integral from zero to infinity g1*g2 using a G function,
1292
+ assuming the necessary conditions are fulfilled.
1293
+
1294
+ Examples
1295
+ ========
1296
+
1297
+ >>> from sympy.integrals.meijerint import _int0oo
1298
+ >>> from sympy.abc import s, t, m
1299
+ >>> from sympy import meijerg, S
1300
+ >>> g1 = meijerg([], [], [-S(1)/2, 0], [], s**2*t/4)
1301
+ >>> g2 = meijerg([], [], [m/2], [-m/2], t/4)
1302
+ >>> _int0oo(g1, g2, t)
1303
+ 4*meijerg(((0, 1/2), ()), ((m/2,), (-m/2,)), s**(-2))/s**2
1304
+ """
1305
+ # See: [L, section 5.6.2, equation (1)]
1306
+ eta, _ = _get_coeff_exp(g1.argument, x)
1307
+ omega, _ = _get_coeff_exp(g2.argument, x)
1308
+
1309
+ def neg(l):
1310
+ return [-x for x in l]
1311
+ a1 = neg(g1.bm) + list(g2.an)
1312
+ a2 = list(g2.aother) + neg(g1.bother)
1313
+ b1 = neg(g1.an) + list(g2.bm)
1314
+ b2 = list(g2.bother) + neg(g1.aother)
1315
+ return meijerg(a1, a2, b1, b2, omega/eta)/eta
1316
+
1317
+
1318
+ def _rewrite_inversion(fac, po, g, x):
1319
+ """ Absorb ``po`` == x**s into g. """
1320
+ _, s = _get_coeff_exp(po, x)
1321
+ a, b = _get_coeff_exp(g.argument, x)
1322
+
1323
+ def tr(l):
1324
+ return [t + s/b for t in l]
1325
+ from sympy.simplify import powdenest
1326
+ return (powdenest(fac/a**(s/b), polar=True),
1327
+ meijerg(tr(g.an), tr(g.aother), tr(g.bm), tr(g.bother), g.argument))
1328
+
1329
+
1330
+ def _check_antecedents_inversion(g, x):
1331
+ """ Check antecedents for the laplace inversion integral. """
1332
+ _debug('Checking antecedents for inversion:')
1333
+ z = g.argument
1334
+ _, e = _get_coeff_exp(z, x)
1335
+ if e < 0:
1336
+ _debug(' Flipping G.')
1337
+ # We want to assume that argument gets large as |x| -> oo
1338
+ return _check_antecedents_inversion(_flip_g(g), x)
1339
+
1340
+ def statement_half(a, b, c, z, plus):
1341
+ coeff, exponent = _get_coeff_exp(z, x)
1342
+ a *= exponent
1343
+ b *= coeff**c
1344
+ c *= exponent
1345
+ conds = []
1346
+ wp = b*exp(S.ImaginaryUnit*re(c)*pi/2)
1347
+ wm = b*exp(-S.ImaginaryUnit*re(c)*pi/2)
1348
+ if plus:
1349
+ w = wp
1350
+ else:
1351
+ w = wm
1352
+ conds += [And(Or(Eq(b, 0), re(c) <= 0), re(a) <= -1)]
1353
+ conds += [And(Ne(b, 0), Eq(im(c), 0), re(c) > 0, re(w) < 0)]
1354
+ conds += [And(Ne(b, 0), Eq(im(c), 0), re(c) > 0, re(w) <= 0,
1355
+ re(a) <= -1)]
1356
+ return Or(*conds)
1357
+
1358
+ def statement(a, b, c, z):
1359
+ """ Provide a convergence statement for z**a * exp(b*z**c),
1360
+ c/f sphinx docs. """
1361
+ return And(statement_half(a, b, c, z, True),
1362
+ statement_half(a, b, c, z, False))
1363
+
1364
+ # Notations from [L], section 5.7-10
1365
+ m, n, p, q = S([len(g.bm), len(g.an), len(g.ap), len(g.bq)])
1366
+ tau = m + n - p
1367
+ nu = q - m - n
1368
+ rho = (tau - nu)/2
1369
+ sigma = q - p
1370
+ if sigma == 1:
1371
+ epsilon = S.Half
1372
+ elif sigma > 1:
1373
+ epsilon = 1
1374
+ else:
1375
+ epsilon = S.NaN
1376
+ theta = ((1 - sigma)/2 + Add(*g.bq) - Add(*g.ap))/sigma
1377
+ delta = g.delta
1378
+ _debugf(' m=%s, n=%s, p=%s, q=%s, tau=%s, nu=%s, rho=%s, sigma=%s',
1379
+ (m, n, p, q, tau, nu, rho, sigma))
1380
+ _debugf(' epsilon=%s, theta=%s, delta=%s', (epsilon, theta, delta))
1381
+
1382
+ # First check if the computation is valid.
1383
+ if not (g.delta >= e/2 or (p >= 1 and p >= q)):
1384
+ _debug(' Computation not valid for these parameters.')
1385
+ return False
1386
+
1387
+ # Now check if the inversion integral exists.
1388
+
1389
+ # Test "condition A"
1390
+ for a, b in itertools.product(g.an, g.bm):
1391
+ if (a - b).is_integer and a > b:
1392
+ _debug(' Not a valid G function.')
1393
+ return False
1394
+
1395
+ # There are two cases. If p >= q, we can directly use a slater expansion
1396
+ # like [L], 5.2 (11). Note in particular that the asymptotics of such an
1397
+ # expansion even hold when some of the parameters differ by integers, i.e.
1398
+ # the formula itself would not be valid! (b/c G functions are cts. in their
1399
+ # parameters)
1400
+ # When p < q, we need to use the theorems of [L], 5.10.
1401
+
1402
+ if p >= q:
1403
+ _debug(' Using asymptotic Slater expansion.')
1404
+ return And(*[statement(a - 1, 0, 0, z) for a in g.an])
1405
+
1406
+ def E(z):
1407
+ return And(*[statement(a - 1, 0, 0, z) for a in g.an])
1408
+
1409
+ def H(z):
1410
+ return statement(theta, -sigma, 1/sigma, z)
1411
+
1412
+ def Hp(z):
1413
+ return statement_half(theta, -sigma, 1/sigma, z, True)
1414
+
1415
+ def Hm(z):
1416
+ return statement_half(theta, -sigma, 1/sigma, z, False)
1417
+
1418
+ # [L], section 5.10
1419
+ conds = []
1420
+ # Theorem 1 -- p < q from test above
1421
+ conds += [And(1 <= n, 1 <= m, rho*pi - delta >= pi/2, delta > 0,
1422
+ E(z*exp(S.ImaginaryUnit*pi*(nu + 1))))]
1423
+ # Theorem 2, statements (2) and (3)
1424
+ conds += [And(p + 1 <= m, m + 1 <= q, delta > 0, delta < pi/2, n == 0,
1425
+ (m - p + 1)*pi - delta >= pi/2,
1426
+ Hp(z*exp(S.ImaginaryUnit*pi*(q - m))),
1427
+ Hm(z*exp(-S.ImaginaryUnit*pi*(q - m))))]
1428
+ # Theorem 2, statement (5) -- p < q from test above
1429
+ conds += [And(m == q, n == 0, delta > 0,
1430
+ (sigma + epsilon)*pi - delta >= pi/2, H(z))]
1431
+ # Theorem 3, statements (6) and (7)
1432
+ conds += [And(Or(And(p <= q - 2, 1 <= tau, tau <= sigma/2),
1433
+ And(p + 1 <= m + n, m + n <= (p + q)/2)),
1434
+ delta > 0, delta < pi/2, (tau + 1)*pi - delta >= pi/2,
1435
+ Hp(z*exp(S.ImaginaryUnit*pi*nu)),
1436
+ Hm(z*exp(-S.ImaginaryUnit*pi*nu)))]
1437
+ # Theorem 4, statements (10) and (11) -- p < q from test above
1438
+ conds += [And(1 <= m, rho > 0, delta > 0, delta + rho*pi < pi/2,
1439
+ (tau + epsilon)*pi - delta >= pi/2,
1440
+ Hp(z*exp(S.ImaginaryUnit*pi*nu)),
1441
+ Hm(z*exp(-S.ImaginaryUnit*pi*nu)))]
1442
+ # Trivial case
1443
+ conds += [m == 0]
1444
+
1445
+ # TODO
1446
+ # Theorem 5 is quite general
1447
+ # Theorem 6 contains special cases for q=p+1
1448
+
1449
+ return Or(*conds)
1450
+
1451
+
1452
+ def _int_inversion(g, x, t):
1453
+ """
1454
+ Compute the laplace inversion integral, assuming the formula applies.
1455
+ """
1456
+ b, a = _get_coeff_exp(g.argument, x)
1457
+ C, g = _inflate_fox_h(meijerg(g.an, g.aother, g.bm, g.bother, b/t**a), -a)
1458
+ return C/t*g
1459
+
1460
+
1461
+ ####################################################################
1462
+ # Finally, the real meat.
1463
+ ####################################################################
1464
+
1465
+ _lookup_table = None
1466
+
1467
+
1468
+ @cacheit
1469
+ @timeit
1470
+ def _rewrite_single(f, x, recursive=True):
1471
+ """
1472
+ Try to rewrite f as a sum of single G functions of the form
1473
+ C*x**s*G(a*x**b), where b is a rational number and C is independent of x.
1474
+ We guarantee that result.argument.as_coeff_mul(x) returns (a, (x**b,))
1475
+ or (a, ()).
1476
+ Returns a list of tuples (C, s, G) and a condition cond.
1477
+ Returns None on failure.
1478
+ """
1479
+ from .transforms import (mellin_transform, inverse_mellin_transform,
1480
+ IntegralTransformError, MellinTransformStripError)
1481
+
1482
+ global _lookup_table
1483
+ if not _lookup_table:
1484
+ _lookup_table = {}
1485
+ _create_lookup_table(_lookup_table)
1486
+
1487
+ if isinstance(f, meijerg):
1488
+ coeff, m = factor(f.argument, x).as_coeff_mul(x)
1489
+ if len(m) > 1:
1490
+ return None
1491
+ m = m[0]
1492
+ if m.is_Pow:
1493
+ if m.base != x or not m.exp.is_Rational:
1494
+ return None
1495
+ elif m != x:
1496
+ return None
1497
+ return [(1, 0, meijerg(f.an, f.aother, f.bm, f.bother, coeff*m))], True
1498
+
1499
+ f_ = f
1500
+ f = f.subs(x, z)
1501
+ t = _mytype(f, z)
1502
+ if t in _lookup_table:
1503
+ l = _lookup_table[t]
1504
+ for formula, terms, cond, hint in l:
1505
+ subs = f.match(formula, old=True)
1506
+ if subs:
1507
+ subs_ = {}
1508
+ for fro, to in subs.items():
1509
+ subs_[fro] = unpolarify(polarify(to, lift=True),
1510
+ exponents_only=True)
1511
+ subs = subs_
1512
+ if not isinstance(hint, bool):
1513
+ hint = hint.subs(subs)
1514
+ if hint == False:
1515
+ continue
1516
+ if not isinstance(cond, (bool, BooleanAtom)):
1517
+ cond = unpolarify(cond.subs(subs))
1518
+ if _eval_cond(cond) == False:
1519
+ continue
1520
+ if not isinstance(terms, list):
1521
+ terms = terms(subs)
1522
+ res = []
1523
+ for fac, g in terms:
1524
+ r1 = _get_coeff_exp(unpolarify(fac.subs(subs).subs(z, x),
1525
+ exponents_only=True), x)
1526
+ try:
1527
+ g = g.subs(subs).subs(z, x)
1528
+ except ValueError:
1529
+ continue
1530
+ # NOTE these substitutions can in principle introduce oo,
1531
+ # zoo and other absurdities. It shouldn't matter,
1532
+ # but better be safe.
1533
+ if Tuple(*(r1 + (g,))).has(S.Infinity, S.ComplexInfinity, S.NegativeInfinity):
1534
+ continue
1535
+ g = meijerg(g.an, g.aother, g.bm, g.bother,
1536
+ unpolarify(g.argument, exponents_only=True))
1537
+ res.append(r1 + (g,))
1538
+ if res:
1539
+ return res, cond
1540
+
1541
+ # try recursive mellin transform
1542
+ if not recursive:
1543
+ return None
1544
+ _debug('Trying recursive Mellin transform method.')
1545
+
1546
+ def my_imt(F, s, x, strip):
1547
+ """ Calling simplify() all the time is slow and not helpful, since
1548
+ most of the time it only factors things in a way that has to be
1549
+ un-done anyway. But sometimes it can remove apparent poles. """
1550
+ # XXX should this be in inverse_mellin_transform?
1551
+ try:
1552
+ return inverse_mellin_transform(F, s, x, strip,
1553
+ as_meijerg=True, needeval=True)
1554
+ except MellinTransformStripError:
1555
+ from sympy.simplify import simplify
1556
+ return inverse_mellin_transform(
1557
+ simplify(cancel(expand(F))), s, x, strip,
1558
+ as_meijerg=True, needeval=True)
1559
+ f = f_
1560
+ s = _dummy('s', 'rewrite-single', f)
1561
+ # to avoid infinite recursion, we have to force the two g functions case
1562
+
1563
+ def my_integrator(f, x):
1564
+ r = _meijerint_definite_4(f, x, only_double=True)
1565
+ if r is not None:
1566
+ from sympy.simplify import hyperexpand
1567
+ res, cond = r
1568
+ res = _my_unpolarify(hyperexpand(res, rewrite='nonrepsmall'))
1569
+ return Piecewise((res, cond),
1570
+ (Integral(f, (x, S.Zero, S.Infinity)), True))
1571
+ return Integral(f, (x, S.Zero, S.Infinity))
1572
+ try:
1573
+ F, strip, _ = mellin_transform(f, x, s, integrator=my_integrator,
1574
+ simplify=False, needeval=True)
1575
+ g = my_imt(F, s, x, strip)
1576
+ except IntegralTransformError:
1577
+ g = None
1578
+ if g is None:
1579
+ # We try to find an expression by analytic continuation.
1580
+ # (also if the dummy is already in the expression, there is no point in
1581
+ # putting in another one)
1582
+ a = _dummy_('a', 'rewrite-single')
1583
+ if a not in f.free_symbols and _is_analytic(f, x):
1584
+ try:
1585
+ F, strip, _ = mellin_transform(f.subs(x, a*x), x, s,
1586
+ integrator=my_integrator,
1587
+ needeval=True, simplify=False)
1588
+ g = my_imt(F, s, x, strip).subs(a, 1)
1589
+ except IntegralTransformError:
1590
+ g = None
1591
+ if g is None or g.has(S.Infinity, S.NaN, S.ComplexInfinity):
1592
+ _debug('Recursive Mellin transform failed.')
1593
+ return None
1594
+ args = Add.make_args(g)
1595
+ res = []
1596
+ for f in args:
1597
+ c, m = f.as_coeff_mul(x)
1598
+ if len(m) > 1:
1599
+ raise NotImplementedError('Unexpected form...')
1600
+ g = m[0]
1601
+ a, b = _get_coeff_exp(g.argument, x)
1602
+ res += [(c, 0, meijerg(g.an, g.aother, g.bm, g.bother,
1603
+ unpolarify(polarify(
1604
+ a, lift=True), exponents_only=True)
1605
+ *x**b))]
1606
+ _debug('Recursive Mellin transform worked:', g)
1607
+ return res, True
1608
+
1609
+
1610
+ def _rewrite1(f, x, recursive=True):
1611
+ """
1612
+ Try to rewrite ``f`` using a (sum of) single G functions with argument a*x**b.
1613
+ Return fac, po, g such that f = fac*po*g, fac is independent of ``x``.
1614
+ and po = x**s.
1615
+ Here g is a result from _rewrite_single.
1616
+ Return None on failure.
1617
+ """
1618
+ fac, po, g = _split_mul(f, x)
1619
+ g = _rewrite_single(g, x, recursive)
1620
+ if g:
1621
+ return fac, po, g[0], g[1]
1622
+
1623
+
1624
+ def _rewrite2(f, x):
1625
+ """
1626
+ Try to rewrite ``f`` as a product of two G functions of arguments a*x**b.
1627
+ Return fac, po, g1, g2 such that f = fac*po*g1*g2, where fac is
1628
+ independent of x and po is x**s.
1629
+ Here g1 and g2 are results of _rewrite_single.
1630
+ Returns None on failure.
1631
+ """
1632
+ fac, po, g = _split_mul(f, x)
1633
+ if any(_rewrite_single(expr, x, False) is None for expr in _mul_args(g)):
1634
+ return None
1635
+ l = _mul_as_two_parts(g)
1636
+ if not l:
1637
+ return None
1638
+ l = list(ordered(l, [
1639
+ lambda p: max(len(_exponents(p[0], x)), len(_exponents(p[1], x))),
1640
+ lambda p: max(len(_functions(p[0], x)), len(_functions(p[1], x))),
1641
+ lambda p: max(len(_find_splitting_points(p[0], x)),
1642
+ len(_find_splitting_points(p[1], x)))]))
1643
+
1644
+ for recursive, (fac1, fac2) in itertools.product((False, True), l):
1645
+ g1 = _rewrite_single(fac1, x, recursive)
1646
+ g2 = _rewrite_single(fac2, x, recursive)
1647
+ if g1 and g2:
1648
+ cond = And(g1[1], g2[1])
1649
+ if cond != False:
1650
+ return fac, po, g1[0], g2[0], cond
1651
+
1652
+
1653
+ def meijerint_indefinite(f, x):
1654
+ """
1655
+ Compute an indefinite integral of ``f`` by rewriting it as a G function.
1656
+
1657
+ Examples
1658
+ ========
1659
+
1660
+ >>> from sympy.integrals.meijerint import meijerint_indefinite
1661
+ >>> from sympy import sin
1662
+ >>> from sympy.abc import x
1663
+ >>> meijerint_indefinite(sin(x), x)
1664
+ -cos(x)
1665
+ """
1666
+ f = sympify(f)
1667
+ results = []
1668
+ for a in sorted(_find_splitting_points(f, x) | {S.Zero}, key=default_sort_key):
1669
+ res = _meijerint_indefinite_1(f.subs(x, x + a), x)
1670
+ if not res:
1671
+ continue
1672
+ res = res.subs(x, x - a)
1673
+ if _has(res, hyper, meijerg):
1674
+ results.append(res)
1675
+ else:
1676
+ return res
1677
+ if f.has(HyperbolicFunction):
1678
+ _debug('Try rewriting hyperbolics in terms of exp.')
1679
+ rv = meijerint_indefinite(
1680
+ _rewrite_hyperbolics_as_exp(f), x)
1681
+ if rv:
1682
+ if not isinstance(rv, list):
1683
+ from sympy.simplify.radsimp import collect
1684
+ return collect(factor_terms(rv), rv.atoms(exp))
1685
+ results.extend(rv)
1686
+ if results:
1687
+ return next(ordered(results))
1688
+
1689
+
1690
+ def _meijerint_indefinite_1(f, x):
1691
+ """ Helper that does not attempt any substitution. """
1692
+ _debug('Trying to compute the indefinite integral of', f, 'wrt', x)
1693
+ from sympy.simplify import hyperexpand, powdenest
1694
+
1695
+ gs = _rewrite1(f, x)
1696
+ if gs is None:
1697
+ # Note: the code that calls us will do expand() and try again
1698
+ return None
1699
+
1700
+ fac, po, gl, cond = gs
1701
+ _debug(' could rewrite:', gs)
1702
+ res = S.Zero
1703
+ for C, s, g in gl:
1704
+ a, b = _get_coeff_exp(g.argument, x)
1705
+ _, c = _get_coeff_exp(po, x)
1706
+ c += s
1707
+
1708
+ # we do a substitution t=a*x**b, get integrand fac*t**rho*g
1709
+ fac_ = fac * C * x**(1 + c) / b
1710
+ rho = (c + 1)/b
1711
+
1712
+ # we now use t**rho*G(params, t) = G(params + rho, t)
1713
+ # [L, page 150, equation (4)]
1714
+ # and integral G(params, t) dt = G(1, params+1, 0, t)
1715
+ # (or a similar expression with 1 and 0 exchanged ... pick the one
1716
+ # which yields a well-defined function)
1717
+ # [R, section 5]
1718
+ # (Note that this dummy will immediately go away again, so we
1719
+ # can safely pass S.One for ``expr``.)
1720
+ t = _dummy('t', 'meijerint-indefinite', S.One)
1721
+
1722
+ def tr(p):
1723
+ return [a + rho for a in p]
1724
+ if any(b.is_integer and (b <= 0) == True for b in tr(g.bm)):
1725
+ r = -meijerg(
1726
+ list(g.an), list(g.aother) + [1-rho], list(g.bm) + [-rho], list(g.bother), t)
1727
+ else:
1728
+ r = meijerg(
1729
+ list(g.an) + [1-rho], list(g.aother), list(g.bm), list(g.bother) + [-rho], t)
1730
+ # The antiderivative is most often expected to be defined
1731
+ # in the neighborhood of x = 0.
1732
+ if b.is_extended_nonnegative and not f.subs(x, 0).has(S.NaN, S.ComplexInfinity):
1733
+ place = 0 # Assume we can expand at zero
1734
+ else:
1735
+ place = None
1736
+ r = hyperexpand(r.subs(t, a*x**b), place=place)
1737
+
1738
+ # now substitute back
1739
+ # Note: we really do want the powers of x to combine.
1740
+ res += powdenest(fac_*r, polar=True)
1741
+
1742
+ def _clean(res):
1743
+ """This multiplies out superfluous powers of x we created, and chops off
1744
+ constants:
1745
+
1746
+ >> _clean(x*(exp(x)/x - 1/x) + 3)
1747
+ exp(x)
1748
+
1749
+ cancel is used before mul_expand since it is possible for an
1750
+ expression to have an additive constant that does not become isolated
1751
+ with simple expansion. Such a situation was identified in issue 6369:
1752
+
1753
+ Examples
1754
+ ========
1755
+
1756
+ >>> from sympy import sqrt, cancel
1757
+ >>> from sympy.abc import x
1758
+ >>> a = sqrt(2*x + 1)
1759
+ >>> bad = (3*x*a**5 + 2*x - a**5 + 1)/a**2
1760
+ >>> bad.expand().as_independent(x)[0]
1761
+ 0
1762
+ >>> cancel(bad).expand().as_independent(x)[0]
1763
+ 1
1764
+ """
1765
+ res = expand_mul(cancel(res), deep=False)
1766
+ return Add._from_args(res.as_coeff_add(x)[1])
1767
+
1768
+ res = piecewise_fold(res, evaluate=None)
1769
+ if res.is_Piecewise:
1770
+ newargs = []
1771
+ for e, c in res.args:
1772
+ e = _my_unpolarify(_clean(e))
1773
+ newargs += [(e, c)]
1774
+ res = Piecewise(*newargs, evaluate=False)
1775
+ else:
1776
+ res = _my_unpolarify(_clean(res))
1777
+ return Piecewise((res, _my_unpolarify(cond)), (Integral(f, x), True))
1778
+
1779
+
1780
+ @timeit
1781
+ def meijerint_definite(f, x, a, b):
1782
+ """
1783
+ Integrate ``f`` over the interval [``a``, ``b``], by rewriting it as a product
1784
+ of two G functions, or as a single G function.
1785
+
1786
+ Return res, cond, where cond are convergence conditions.
1787
+
1788
+ Examples
1789
+ ========
1790
+
1791
+ >>> from sympy.integrals.meijerint import meijerint_definite
1792
+ >>> from sympy import exp, oo
1793
+ >>> from sympy.abc import x
1794
+ >>> meijerint_definite(exp(-x**2), x, -oo, oo)
1795
+ (sqrt(pi), True)
1796
+
1797
+ This function is implemented as a succession of functions
1798
+ meijerint_definite, _meijerint_definite_2, _meijerint_definite_3,
1799
+ _meijerint_definite_4. Each function in the list calls the next one
1800
+ (presumably) several times. This means that calling meijerint_definite
1801
+ can be very costly.
1802
+ """
1803
+ # This consists of three steps:
1804
+ # 1) Change the integration limits to 0, oo
1805
+ # 2) Rewrite in terms of G functions
1806
+ # 3) Evaluate the integral
1807
+ #
1808
+ # There are usually several ways of doing this, and we want to try all.
1809
+ # This function does (1), calls _meijerint_definite_2 for step (2).
1810
+ _debugf('Integrating %s wrt %s from %s to %s.', (f, x, a, b))
1811
+ f = sympify(f)
1812
+ if f.has(DiracDelta):
1813
+ _debug('Integrand has DiracDelta terms - giving up.')
1814
+ return None
1815
+
1816
+ if f.has(SingularityFunction):
1817
+ _debug('Integrand has Singularity Function terms - giving up.')
1818
+ return None
1819
+
1820
+ f_, x_, a_, b_ = f, x, a, b
1821
+
1822
+ # Let's use a dummy in case any of the boundaries has x.
1823
+ d = Dummy('x')
1824
+ f = f.subs(x, d)
1825
+ x = d
1826
+
1827
+ if a == b:
1828
+ return (S.Zero, True)
1829
+
1830
+ results = []
1831
+ if a is S.NegativeInfinity and b is not S.Infinity:
1832
+ return meijerint_definite(f.subs(x, -x), x, -b, -a)
1833
+
1834
+ elif a is S.NegativeInfinity:
1835
+ # Integrating -oo to oo. We need to find a place to split the integral.
1836
+ _debug(' Integrating -oo to +oo.')
1837
+ innermost = _find_splitting_points(f, x)
1838
+ _debug(' Sensible splitting points:', innermost)
1839
+ for c in sorted(innermost, key=default_sort_key, reverse=True) + [S.Zero]:
1840
+ _debug(' Trying to split at', c)
1841
+ if not c.is_extended_real:
1842
+ _debug(' Non-real splitting point.')
1843
+ continue
1844
+ res1 = _meijerint_definite_2(f.subs(x, x + c), x)
1845
+ if res1 is None:
1846
+ _debug(' But could not compute first integral.')
1847
+ continue
1848
+ res2 = _meijerint_definite_2(f.subs(x, c - x), x)
1849
+ if res2 is None:
1850
+ _debug(' But could not compute second integral.')
1851
+ continue
1852
+ res1, cond1 = res1
1853
+ res2, cond2 = res2
1854
+ cond = _condsimp(And(cond1, cond2))
1855
+ if cond == False:
1856
+ _debug(' But combined condition is always false.')
1857
+ continue
1858
+ res = res1 + res2
1859
+ return res, cond
1860
+
1861
+ elif a is S.Infinity:
1862
+ res = meijerint_definite(f, x, b, S.Infinity)
1863
+ return -res[0], res[1]
1864
+
1865
+ elif (a, b) == (S.Zero, S.Infinity):
1866
+ # This is a common case - try it directly first.
1867
+ res = _meijerint_definite_2(f, x)
1868
+ if res:
1869
+ if _has(res[0], meijerg):
1870
+ results.append(res)
1871
+ else:
1872
+ return res
1873
+
1874
+ else:
1875
+ if b is S.Infinity:
1876
+ for split in _find_splitting_points(f, x):
1877
+ if (a - split >= 0) == True:
1878
+ _debugf('Trying x -> x + %s', split)
1879
+ res = _meijerint_definite_2(f.subs(x, x + split)
1880
+ *Heaviside(x + split - a), x)
1881
+ if res:
1882
+ if _has(res[0], meijerg):
1883
+ results.append(res)
1884
+ else:
1885
+ return res
1886
+
1887
+ f = f.subs(x, x + a)
1888
+ b = b - a
1889
+ a = 0
1890
+ if b is not S.Infinity:
1891
+ phi = exp(S.ImaginaryUnit*arg(b))
1892
+ b = Abs(b)
1893
+ f = f.subs(x, phi*x)
1894
+ f *= Heaviside(b - x)*phi
1895
+ b = S.Infinity
1896
+
1897
+ _debug('Changed limits to', a, b)
1898
+ _debug('Changed function to', f)
1899
+ res = _meijerint_definite_2(f, x)
1900
+ if res:
1901
+ if _has(res[0], meijerg):
1902
+ results.append(res)
1903
+ else:
1904
+ return res
1905
+ if f_.has(HyperbolicFunction):
1906
+ _debug('Try rewriting hyperbolics in terms of exp.')
1907
+ rv = meijerint_definite(
1908
+ _rewrite_hyperbolics_as_exp(f_), x_, a_, b_)
1909
+ if rv:
1910
+ if not isinstance(rv, list):
1911
+ from sympy.simplify.radsimp import collect
1912
+ rv = (collect(factor_terms(rv[0]), rv[0].atoms(exp)),) + rv[1:]
1913
+ return rv
1914
+ results.extend(rv)
1915
+ if results:
1916
+ return next(ordered(results))
1917
+
1918
+
1919
+ def _guess_expansion(f, x):
1920
+ """ Try to guess sensible rewritings for integrand f(x). """
1921
+ res = [(f, 'original integrand')]
1922
+
1923
+ orig = res[-1][0]
1924
+ saw = {orig}
1925
+ expanded = expand_mul(orig)
1926
+ if expanded not in saw:
1927
+ res += [(expanded, 'expand_mul')]
1928
+ saw.add(expanded)
1929
+
1930
+ expanded = expand(orig)
1931
+ if expanded not in saw:
1932
+ res += [(expanded, 'expand')]
1933
+ saw.add(expanded)
1934
+
1935
+ if orig.has(TrigonometricFunction, HyperbolicFunction):
1936
+ expanded = expand_mul(expand_trig(orig))
1937
+ if expanded not in saw:
1938
+ res += [(expanded, 'expand_trig, expand_mul')]
1939
+ saw.add(expanded)
1940
+
1941
+ if orig.has(cos, sin):
1942
+ from sympy.simplify.fu import sincos_to_sum
1943
+ reduced = sincos_to_sum(orig)
1944
+ if reduced not in saw:
1945
+ res += [(reduced, 'trig power reduction')]
1946
+ saw.add(reduced)
1947
+
1948
+ return res
1949
+
1950
+
1951
+ def _meijerint_definite_2(f, x):
1952
+ """
1953
+ Try to integrate f dx from zero to infinity.
1954
+
1955
+ The body of this function computes various 'simplifications'
1956
+ f1, f2, ... of f (e.g. by calling expand_mul(), trigexpand()
1957
+ - see _guess_expansion) and calls _meijerint_definite_3 with each of
1958
+ these in succession.
1959
+ If _meijerint_definite_3 succeeds with any of the simplified functions,
1960
+ returns this result.
1961
+ """
1962
+ # This function does preparation for (2), calls
1963
+ # _meijerint_definite_3 for (2) and (3) combined.
1964
+
1965
+ # use a positive dummy - we integrate from 0 to oo
1966
+ # XXX if a nonnegative symbol is used there will be test failures
1967
+ dummy = _dummy('x', 'meijerint-definite2', f, positive=True)
1968
+ f = f.subs(x, dummy)
1969
+ x = dummy
1970
+
1971
+ if f == 0:
1972
+ return S.Zero, True
1973
+
1974
+ for g, explanation in _guess_expansion(f, x):
1975
+ _debug('Trying', explanation)
1976
+ res = _meijerint_definite_3(g, x)
1977
+ if res:
1978
+ return res
1979
+
1980
+
1981
+ def _meijerint_definite_3(f, x):
1982
+ """
1983
+ Try to integrate f dx from zero to infinity.
1984
+
1985
+ This function calls _meijerint_definite_4 to try to compute the
1986
+ integral. If this fails, it tries using linearity.
1987
+ """
1988
+ res = _meijerint_definite_4(f, x)
1989
+ if res and res[1] != False:
1990
+ return res
1991
+ if f.is_Add:
1992
+ _debug('Expanding and evaluating all terms.')
1993
+ ress = [_meijerint_definite_4(g, x) for g in f.args]
1994
+ if all(r is not None for r in ress):
1995
+ conds = []
1996
+ res = S.Zero
1997
+ for r, c in ress:
1998
+ res += r
1999
+ conds += [c]
2000
+ c = And(*conds)
2001
+ if c != False:
2002
+ return res, c
2003
+
2004
+
2005
+ def _my_unpolarify(f):
2006
+ return _eval_cond(unpolarify(f))
2007
+
2008
+
2009
+ @timeit
2010
+ def _meijerint_definite_4(f, x, only_double=False):
2011
+ """
2012
+ Try to integrate f dx from zero to infinity.
2013
+
2014
+ Explanation
2015
+ ===========
2016
+
2017
+ This function tries to apply the integration theorems found in literature,
2018
+ i.e. it tries to rewrite f as either one or a product of two G-functions.
2019
+
2020
+ The parameter ``only_double`` is used internally in the recursive algorithm
2021
+ to disable trying to rewrite f as a single G-function.
2022
+ """
2023
+ from sympy.simplify import hyperexpand
2024
+ # This function does (2) and (3)
2025
+ _debug('Integrating', f)
2026
+ # Try single G function.
2027
+ if not only_double:
2028
+ gs = _rewrite1(f, x, recursive=False)
2029
+ if gs is not None:
2030
+ fac, po, g, cond = gs
2031
+ _debug('Could rewrite as single G function:', fac, po, g)
2032
+ res = S.Zero
2033
+ for C, s, f in g:
2034
+ if C == 0:
2035
+ continue
2036
+ C, f = _rewrite_saxena_1(fac*C, po*x**s, f, x)
2037
+ res += C*_int0oo_1(f, x)
2038
+ cond = And(cond, _check_antecedents_1(f, x))
2039
+ if cond == False:
2040
+ break
2041
+ cond = _my_unpolarify(cond)
2042
+ if cond == False:
2043
+ _debug('But cond is always False.')
2044
+ else:
2045
+ _debug('Result before branch substitutions is:', res)
2046
+ return _my_unpolarify(hyperexpand(res)), cond
2047
+
2048
+ # Try two G functions.
2049
+ gs = _rewrite2(f, x)
2050
+ if gs is not None:
2051
+ for full_pb in [False, True]:
2052
+ fac, po, g1, g2, cond = gs
2053
+ _debug('Could rewrite as two G functions:', fac, po, g1, g2)
2054
+ res = S.Zero
2055
+ for C1, s1, f1 in g1:
2056
+ for C2, s2, f2 in g2:
2057
+ r = _rewrite_saxena(fac*C1*C2, po*x**(s1 + s2),
2058
+ f1, f2, x, full_pb)
2059
+ if r is None:
2060
+ _debug('Non-rational exponents.')
2061
+ return
2062
+ C, f1_, f2_ = r
2063
+ _debug('Saxena subst for yielded:', C, f1_, f2_)
2064
+ cond = And(cond, _check_antecedents(f1_, f2_, x))
2065
+ if cond == False:
2066
+ break
2067
+ res += C*_int0oo(f1_, f2_, x)
2068
+ else:
2069
+ continue
2070
+ break
2071
+ cond = _my_unpolarify(cond)
2072
+ if cond == False:
2073
+ _debugf('But cond is always False (full_pb=%s).', full_pb)
2074
+ else:
2075
+ _debugf('Result before branch substitutions is: %s', (res, ))
2076
+ if only_double:
2077
+ return res, cond
2078
+ return _my_unpolarify(hyperexpand(res)), cond
2079
+
2080
+
2081
+ def meijerint_inversion(f, x, t):
2082
+ r"""
2083
+ Compute the inverse laplace transform
2084
+ $\int_{c+i\infty}^{c-i\infty} f(x) e^{tx}\, dx$,
2085
+ for real c larger than the real part of all singularities of ``f``.
2086
+
2087
+ Note that ``t`` is always assumed real and positive.
2088
+
2089
+ Return None if the integral does not exist or could not be evaluated.
2090
+
2091
+ Examples
2092
+ ========
2093
+
2094
+ >>> from sympy.abc import x, t
2095
+ >>> from sympy.integrals.meijerint import meijerint_inversion
2096
+ >>> meijerint_inversion(1/x, x, t)
2097
+ Heaviside(t)
2098
+ """
2099
+ f_ = f
2100
+ t_ = t
2101
+ t = Dummy('t', polar=True) # We don't want sqrt(t**2) = abs(t) etc
2102
+ f = f.subs(t_, t)
2103
+ _debug('Laplace-inverting', f)
2104
+ if not _is_analytic(f, x):
2105
+ _debug('But expression is not analytic.')
2106
+ return None
2107
+ # Exponentials correspond to shifts; we filter them out and then
2108
+ # shift the result later. If we are given an Add this will not
2109
+ # work, but the calling code will take care of that.
2110
+ shift = S.Zero
2111
+
2112
+ if f.is_Mul:
2113
+ args = list(f.args)
2114
+ elif isinstance(f, exp):
2115
+ args = [f]
2116
+ else:
2117
+ args = None
2118
+
2119
+ if args:
2120
+ newargs = []
2121
+ exponentials = []
2122
+ while args:
2123
+ arg = args.pop()
2124
+ if isinstance(arg, exp):
2125
+ arg2 = expand(arg)
2126
+ if arg2.is_Mul:
2127
+ args += arg2.args
2128
+ continue
2129
+ try:
2130
+ a, b = _get_coeff_exp(arg.args[0], x)
2131
+ except _CoeffExpValueError:
2132
+ b = 0
2133
+ if b == 1:
2134
+ exponentials.append(a)
2135
+ else:
2136
+ newargs.append(arg)
2137
+ elif arg.is_Pow:
2138
+ arg2 = expand(arg)
2139
+ if arg2.is_Mul:
2140
+ args += arg2.args
2141
+ continue
2142
+ if x not in arg.base.free_symbols:
2143
+ try:
2144
+ a, b = _get_coeff_exp(arg.exp, x)
2145
+ except _CoeffExpValueError:
2146
+ b = 0
2147
+ if b == 1:
2148
+ exponentials.append(a*log(arg.base))
2149
+ newargs.append(arg)
2150
+ else:
2151
+ newargs.append(arg)
2152
+ shift = Add(*exponentials)
2153
+ f = Mul(*newargs)
2154
+
2155
+ if x not in f.free_symbols:
2156
+ _debug('Expression consists of constant and exp shift:', f, shift)
2157
+ cond = Eq(im(shift), 0)
2158
+ if cond == False:
2159
+ _debug('but shift is nonreal, cannot be a Laplace transform')
2160
+ return None
2161
+ res = f*DiracDelta(t + shift)
2162
+ _debug('Result is a delta function, possibly conditional:', res, cond)
2163
+ # cond is True or Eq
2164
+ return Piecewise((res.subs(t, t_), cond))
2165
+
2166
+ gs = _rewrite1(f, x)
2167
+ if gs is not None:
2168
+ fac, po, g, cond = gs
2169
+ _debug('Could rewrite as single G function:', fac, po, g)
2170
+ res = S.Zero
2171
+ for C, s, f in g:
2172
+ C, f = _rewrite_inversion(fac*C, po*x**s, f, x)
2173
+ res += C*_int_inversion(f, x, t)
2174
+ cond = And(cond, _check_antecedents_inversion(f, x))
2175
+ if cond == False:
2176
+ break
2177
+ cond = _my_unpolarify(cond)
2178
+ if cond == False:
2179
+ _debug('But cond is always False.')
2180
+ else:
2181
+ _debug('Result before branch substitution:', res)
2182
+ from sympy.simplify import hyperexpand
2183
+ res = _my_unpolarify(hyperexpand(res))
2184
+ if not res.has(Heaviside):
2185
+ res *= Heaviside(t)
2186
+ res = res.subs(t, t + shift)
2187
+ if not isinstance(cond, bool):
2188
+ cond = cond.subs(t, t + shift)
2189
+ from .transforms import InverseLaplaceTransform
2190
+ return Piecewise((res.subs(t, t_), cond),
2191
+ (InverseLaplaceTransform(f_.subs(t, t_), x, t_, None), True))
.venv/lib/python3.12/site-packages/sympy/integrals/meijerint_doc.py ADDED
@@ -0,0 +1,38 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ """ This module cooks up a docstring when imported. Its only purpose is to
2
+ be displayed in the sphinx documentation. """
3
+
4
+ from __future__ import annotations
5
+ from typing import Any
6
+
7
+ from sympy.integrals.meijerint import _create_lookup_table
8
+ from sympy.core.add import Add
9
+ from sympy.core.basic import Basic
10
+ from sympy.core.expr import Expr
11
+ from sympy.core.relational import Eq
12
+ from sympy.core.symbol import Symbol
13
+ from sympy.printing.latex import latex
14
+
15
+ t: dict[tuple[type[Basic], ...], list[Any]] = {}
16
+ _create_lookup_table(t)
17
+
18
+
19
+ doc = ""
20
+ for about, category in t.items():
21
+ if about == ():
22
+ doc += 'Elementary functions:\n\n'
23
+ else:
24
+ doc += 'Functions involving ' + ', '.join('`%s`' % latex(
25
+ list(category[0][0].atoms(func))[0]) for func in about) + ':\n\n'
26
+ for formula, gs, cond, hint in category:
27
+ if not isinstance(gs, list):
28
+ g: Expr = Symbol('\\text{generated}')
29
+ else:
30
+ g = Add(*[fac*f for (fac, f) in gs])
31
+ obj = Eq(formula, g)
32
+ if cond is True:
33
+ cond = ""
34
+ else:
35
+ cond = ',\\text{ if } %s' % latex(cond)
36
+ doc += ".. math::\n %s%s\n\n" % (latex(obj), cond)
37
+
38
+ __doc__ = doc