/
basic.py
874 lines (774 loc) · 27.3 KB
/
basic.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
#
# Author: Travis Oliphant, 2002
#
from numpy import pi, asarray, floor, isscalar, iscomplex, real, imag, sqrt, \
where, mgrid, cos, sin, exp, place, seterr, issubdtype, extract, \
complexfloating, less, vectorize, inexact, nan, zeros, sometrue
from _cephes import ellipkm1, mathieu_a, mathieu_b, iv, jv, gamma, psi, zeta, \
hankel1, hankel2, yv, kv, gammaln, errprint, ndtri
import types
import specfun
import orthogonal
__all__ = ['agm', 'ai_zeros', 'assoc_laguerre', 'bei_zeros', 'beip_zeros',
'ber_zeros', 'bernoulli', 'berp_zeros', 'bessel_diff_formula',
'bi_zeros', 'digamma', 'diric', 'ellipk', 'erf_zeros', 'erfcinv',
'erfinv', 'errprint', 'euler', 'fresnel_zeros',
'fresnelc_zeros', 'fresnels_zeros', 'gamma', 'gammaln', 'h1vp',
'h2vp', 'hankel1', 'hankel2', 'hyp0f1', 'iv', 'ivp', 'jn_zeros',
'jnjnp_zeros', 'jnp_zeros', 'jnyn_zeros', 'jv', 'jvp', 'kei_zeros',
'keip_zeros', 'kelvin_zeros', 'ker_zeros', 'kerp_zeros', 'kv',
'kvp', 'lmbda', 'lpmn', 'lpn', 'lqmn', 'lqn', 'mathieu_a',
'mathieu_b', 'mathieu_even_coef', 'mathieu_odd_coef', 'ndtri',
'obl_cv_seq', 'pbdn_seq', 'pbdv_seq', 'pbvv_seq',
'polygamma', 'pro_cv_seq', 'psi', 'riccati_jn', 'riccati_yn',
'sinc', 'sph_harm', 'sph_in', 'sph_inkn',
'sph_jn', 'sph_jnyn', 'sph_kn', 'sph_yn', 'y0_zeros', 'y1_zeros',
'y1p_zeros', 'yn_zeros', 'ynp_zeros', 'yv', 'yvp', 'zeta']
def sinc(x):
"""Returns sin(pi*x)/(pi*x) at all points of array x.
"""
w = pi * asarray(x)
# w might contain 0, and so temporarily turn off warnings
# while calculating sin(w)/w.
old_settings = seterr(all='ignore')
s = sin(w) / w
seterr(**old_settings)
return where(x==0, 1.0, s)
def diric(x,n):
"""Returns the periodic sinc function also called the dirichlet function:
diric(x) = sin(x *n / 2) / (n sin(x / 2))
where n is a positive integer.
"""
x,n = asarray(x), asarray(n)
n = asarray(n + (x-x))
x = asarray(x + (n-n))
if issubdtype(x.dtype, inexact):
ytype = x.dtype
else:
ytype = float
y = zeros(x.shape,ytype)
mask1 = (n <= 0) | (n <> floor(n))
place(y,mask1,nan)
z = asarray(x / 2.0 / pi)
mask2 = (1-mask1) & (z == floor(z))
zsub = extract(mask2,z)
nsub = extract(mask2,n)
place(y,mask2,pow(-1,zsub*(nsub-1)))
mask = (1-mask1) & (1-mask2)
xsub = extract(mask,x)
nsub = extract(mask,n)
place(y,mask,sin(nsub*xsub/2.0)/(nsub*sin(xsub/2.0)))
return y
def jnjnp_zeros(nt):
"""Compute nt (<=1200) zeros of the bessel functions Jn and Jn'
and arange them in order of their magnitudes.
Returns
-------
zo[l-1] : ndarray
Value of the lth zero of of Jn(x) and Jn'(x). Of length `nt`.
n[l-1] : ndarray
Order of the Jn(x) or Jn'(x) associated with lth zero. Of length `nt`.
m[l-1] : ndarray
Serial number of the zeros of Jn(x) or Jn'(x) associated
with lth zero. Of length `nt`.
t[l-1] : ndarray
0 if lth zero in zo is zero of Jn(x), 1 if it is a zero of Jn'(x). Of
length `nt`.
See Also
--------
jn_zeros, jnp_zeros : to get separated arrays of zeros.
"""
if not isscalar(nt) or (floor(nt)!=nt) or (nt>1200):
raise ValueError("Number must be integer <= 1200.")
nt = int(nt)
n,m,t,zo = specfun.jdzo(nt)
return zo[1:nt+1],n[:nt],m[:nt],t[:nt]
def jnyn_zeros(n,nt):
"""Compute nt zeros of the Bessel functions Jn(x), Jn'(x), Yn(x), and
Yn'(x), respectively. Returns 4 arrays of length nt.
See jn_zeros, jnp_zeros, yn_zeros, ynp_zeros to get separate arrays.
"""
if not (isscalar(nt) and isscalar(n)):
raise ValueError("Arguments must be scalars.")
if (floor(n)!=n) or (floor(nt)!=nt):
raise ValueError("Arguments must be integers.")
if (nt <=0):
raise ValueError("nt > 0")
return specfun.jyzo(abs(n),nt)
def jn_zeros(n,nt):
"""Compute nt zeros of the Bessel function Jn(x).
"""
return jnyn_zeros(n,nt)[0]
def jnp_zeros(n,nt):
"""Compute nt zeros of the Bessel function Jn'(x).
"""
return jnyn_zeros(n,nt)[1]
def yn_zeros(n,nt):
"""Compute nt zeros of the Bessel function Yn(x).
"""
return jnyn_zeros(n,nt)[2]
def ynp_zeros(n,nt):
"""Compute nt zeros of the Bessel function Yn'(x).
"""
return jnyn_zeros(n,nt)[3]
def y0_zeros(nt,complex=0):
"""Returns nt (complex or real) zeros of Y0(z), z0, and the value
of Y0'(z0) = -Y1(z0) at each zero.
"""
if not isscalar(nt) or (floor(nt)!=nt) or (nt <=0):
raise ValueError("Arguments must be scalar positive integer.")
kf = 0
kc = (complex != 1)
return specfun.cyzo(nt,kf,kc)
def y1_zeros(nt,complex=0):
"""Returns nt (complex or real) zeros of Y1(z), z1, and the value
of Y1'(z1) = Y0(z1) at each zero.
"""
if not isscalar(nt) or (floor(nt)!=nt) or (nt <=0):
raise ValueError("Arguments must be scalar positive integer.")
kf = 1
kc = (complex != 1)
return specfun.cyzo(nt,kf,kc)
def y1p_zeros(nt,complex=0):
"""Returns nt (complex or real) zeros of Y1'(z), z1', and the value
of Y1(z1') at each zero.
"""
if not isscalar(nt) or (floor(nt)!=nt) or (nt <=0):
raise ValueError("Arguments must be scalar positive integer.")
kf = 2
kc = (complex != 1)
return specfun.cyzo(nt,kf,kc)
def bessel_diff_formula(v, z, n, L, phase):
# from AMS55.
# L(v,z) = J(v,z), Y(v,z), H1(v,z), H2(v,z), phase = -1
# L(v,z) = I(v,z) or exp(v*pi*i)K(v,z), phase = 1
# For K, you can pull out the exp((v-k)*pi*i) into the caller
p = 1.0
s = L(v-n, z)
for i in xrange(1, n+1):
p = phase * (p * (n-i+1)) / i # = choose(k, i)
s += p*L(v-n + i*2, z)
return s / (2.**n)
def jvp(v,z,n=1):
"""Return the nth derivative of Jv(z) with respect to z.
"""
if not isinstance(n,types.IntType) or (n<0):
raise ValueError("n must be a non-negative integer.")
if n == 0:
return jv(v,z)
else:
return bessel_diff_formula(v, z, n, jv, -1)
# return (jvp(v-1,z,n-1) - jvp(v+1,z,n-1))/2.0
def yvp(v,z,n=1):
"""Return the nth derivative of Yv(z) with respect to z.
"""
if not isinstance(n,types.IntType) or (n<0):
raise ValueError("n must be a non-negative integer.")
if n == 0:
return yv(v,z)
else:
return bessel_diff_formula(v, z, n, yv, -1)
# return (yvp(v-1,z,n-1) - yvp(v+1,z,n-1))/2.0
def kvp(v,z,n=1):
"""Return the nth derivative of Kv(z) with respect to z.
"""
if not isinstance(n,types.IntType) or (n<0):
raise ValueError("n must be a non-negative integer.")
if n == 0:
return kv(v,z)
else:
return (-1)**n * bessel_diff_formula(v, z, n, kv, 1)
def ivp(v,z,n=1):
"""Return the nth derivative of Iv(z) with respect to z.
"""
if not isinstance(n,types.IntType) or (n<0):
raise ValueError("n must be a non-negative integer.")
if n == 0:
return iv(v,z)
else:
return bessel_diff_formula(v, z, n, iv, 1)
def h1vp(v,z,n=1):
"""Return the nth derivative of H1v(z) with respect to z.
"""
if not isinstance(n,types.IntType) or (n<0):
raise ValueError("n must be a non-negative integer.")
if n == 0:
return hankel1(v,z)
else:
return bessel_diff_formula(v, z, n, hankel1, -1)
# return (h1vp(v-1,z,n-1) - h1vp(v+1,z,n-1))/2.0
def h2vp(v,z,n=1):
"""Return the nth derivative of H2v(z) with respect to z.
"""
if not isinstance(n,types.IntType) or (n<0):
raise ValueError("n must be a non-negative integer.")
if n == 0:
return hankel2(v,z)
else:
return bessel_diff_formula(v, z, n, hankel2, -1)
# return (h2vp(v-1,z,n-1) - h2vp(v+1,z,n-1))/2.0
def sph_jn(n,z):
"""Compute the spherical Bessel function jn(z) and its derivative for
all orders up to and including n.
"""
if not (isscalar(n) and isscalar(z)):
raise ValueError("arguments must be scalars.")
if (n!= floor(n)) or (n<0):
raise ValueError("n must be a non-negative integer.")
if (n < 1): n1 = 1
else: n1 = n
if iscomplex(z):
nm,jn,jnp,yn,ynp = specfun.csphjy(n1,z)
else:
nm,jn,jnp = specfun.sphj(n1,z)
return jn[:(n+1)], jnp[:(n+1)]
def sph_yn(n,z):
"""Compute the spherical Bessel function yn(z) and its derivative for
all orders up to and including n.
"""
if not (isscalar(n) and isscalar(z)):
raise ValueError("arguments must be scalars.")
if (n!= floor(n)) or (n<0):
raise ValueError("n must be a non-negative integer.")
if (n < 1): n1 = 1
else: n1 = n
if iscomplex(z) or less(z,0):
nm,jn,jnp,yn,ynp = specfun.csphjy(n1,z)
else:
nm,yn,ynp = specfun.sphy(n1,z)
return yn[:(n+1)], ynp[:(n+1)]
def sph_jnyn(n,z):
"""Compute the spherical Bessel functions, jn(z) and yn(z) and their
derivatives for all orders up to and including n.
"""
if not (isscalar(n) and isscalar(z)):
raise ValueError("arguments must be scalars.")
if (n!= floor(n)) or (n<0):
raise ValueError("n must be a non-negative integer.")
if (n < 1): n1 = 1
else: n1 = n
if iscomplex(z) or less(z,0):
nm,jn,jnp,yn,ynp = specfun.csphjy(n1,z)
else:
nm,yn,ynp = specfun.sphy(n1,z)
nm,jn,jnp = specfun.sphj(n1,z)
return jn[:(n+1)],jnp[:(n+1)],yn[:(n+1)],ynp[:(n+1)]
def sph_in(n,z):
"""Compute the spherical Bessel function in(z) and its derivative for
all orders up to and including n.
"""
if not (isscalar(n) and isscalar(z)):
raise ValueError("arguments must be scalars.")
if (n!= floor(n)) or (n<0):
raise ValueError("n must be a non-negative integer.")
if (n < 1): n1 = 1
else: n1 = n
if iscomplex(z):
nm,In,Inp,kn,knp = specfun.csphik(n1,z)
else:
nm,In,Inp = specfun.sphi(n1,z)
return In[:(n+1)], Inp[:(n+1)]
def sph_kn(n,z):
"""Compute the spherical Bessel function kn(z) and its derivative for
all orders up to and including n.
"""
if not (isscalar(n) and isscalar(z)):
raise ValueError("arguments must be scalars.")
if (n!= floor(n)) or (n<0):
raise ValueError("n must be a non-negative integer.")
if (n < 1): n1 = 1
else: n1 = n
if iscomplex(z) or less(z,0):
nm,In,Inp,kn,knp = specfun.csphik(n1,z)
else:
nm,kn,knp = specfun.sphk(n1,z)
return kn[:(n+1)], knp[:(n+1)]
def sph_inkn(n,z):
"""Compute the spherical Bessel functions, in(z) and kn(z) and their
derivatives for all orders up to and including n.
"""
if not (isscalar(n) and isscalar(z)):
raise ValueError("arguments must be scalars.")
if (n!= floor(n)) or (n<0):
raise ValueError("n must be a non-negative integer.")
if iscomplex(z) or less(z,0):
nm,In,Inp,kn,knp = specfun.csphik(n,z)
else:
nm,In,Inp = specfun.sphi(n,z)
nm,kn,knp = specfun.sphk(n,z)
return In,Inp,kn,knp
def riccati_jn(n,x):
"""Compute the Ricatti-Bessel function of the first kind and its
derivative for all orders up to and including n.
"""
if not (isscalar(n) and isscalar(x)):
raise ValueError("arguments must be scalars.")
if (n!= floor(n)) or (n<0):
raise ValueError("n must be a non-negative integer.")
if (n == 0): n1 = 1
else: n1 = n
nm,jn,jnp = specfun.rctj(n1,x)
return jn[:(n+1)],jnp[:(n+1)]
def riccati_yn(n,x):
"""Compute the Ricatti-Bessel function of the second kind and its
derivative for all orders up to and including n.
"""
if not (isscalar(n) and isscalar(x)):
raise ValueError("arguments must be scalars.")
if (n!= floor(n)) or (n<0):
raise ValueError("n must be a non-negative integer.")
if (n == 0): n1 = 1
else: n1 = n
nm,jn,jnp = specfun.rcty(n1,x)
return jn[:(n+1)],jnp[:(n+1)]
def _sph_harmonic(m,n,theta,phi):
"""Compute spherical harmonics.
This is a ufunc and may take scalar or array arguments like any
other ufunc. The inputs will be broadcasted against each other.
Parameters
----------
m : int
|m| <= n; the order of the harmonic.
n : int
where `n` >= 0; the degree of the harmonic. This is often called
``l`` (lower case L) in descriptions of spherical harmonics.
theta : float
[0, 2*pi]; the azimuthal (longitudinal) coordinate.
phi : float
[0, pi]; the polar (colatitudinal) coordinate.
Returns
-------
y_mn : complex float
The harmonic $Y^m_n$ sampled at `theta` and `phi`
Notes
-----
There are different conventions for the meaning of input arguments
`theta` and `phi`. We take `theta` to be the azimuthal angle and
`phi` to be the polar angle. It is common to see the opposite
convention - that is `theta` as the polar angle and `phi` as the
azimuthal angle.
"""
x = cos(phi)
m,n = int(m), int(n)
Pmn,Pmn_deriv = lpmn(m,n,x)
# Legendre call generates all orders up to m and degrees up to n
val = Pmn[-1, -1]
val *= sqrt((2*n+1)/4.0/pi)
val *= exp(0.5*(gammaln(n-m+1)-gammaln(n+m+1)))
val *= exp(1j*m*theta)
return val
sph_harm = vectorize(_sph_harmonic,'D')
def erfinv(y):
return ndtri((y+1)/2.0)/sqrt(2)
def erfcinv(y):
return ndtri((2-y)/2.0)/sqrt(2)
def erf_zeros(nt):
"""Compute nt complex zeros of the error function erf(z).
"""
if (floor(nt)!=nt) or (nt<=0) or not isscalar(nt):
raise ValueError("Argument must be positive scalar integer.")
return specfun.cerzo(nt)
def fresnelc_zeros(nt):
"""Compute nt complex zeros of the cosine fresnel integral C(z).
"""
if (floor(nt)!=nt) or (nt<=0) or not isscalar(nt):
raise ValueError("Argument must be positive scalar integer.")
return specfun.fcszo(1,nt)
def fresnels_zeros(nt):
"""Compute nt complex zeros of the sine fresnel integral S(z).
"""
if (floor(nt)!=nt) or (nt<=0) or not isscalar(nt):
raise ValueError("Argument must be positive scalar integer.")
return specfun.fcszo(2,nt)
def fresnel_zeros(nt):
"""Compute nt complex zeros of the sine and cosine fresnel integrals
S(z) and C(z).
"""
if (floor(nt)!=nt) or (nt<=0) or not isscalar(nt):
raise ValueError("Argument must be positive scalar integer.")
return specfun.fcszo(2,nt), specfun.fcszo(1,nt)
def hyp0f1(v,z):
"""Confluent hypergeometric limit function 0F1.
Limit as q->infinity of 1F1(q;a;z/q)
"""
z = asarray(z)
if issubdtype(z.dtype, complexfloating):
arg = 2*sqrt(abs(z))
num = where(z>=0, iv(v-1,arg), jv(v-1,arg))
den = abs(z)**((v-1.0)/2)
else:
num = iv(v-1,2*sqrt(z))
den = z**((v-1.0)/2.0)
num *= gamma(v)
return where(z==0,1.0,num/ asarray(den))
def assoc_laguerre(x,n,k=0.0):
return orthogonal.eval_genlaguerre(n, k, x)
digamma = psi
def polygamma(n, x):
"""Polygamma function which is the nth derivative of the digamma (psi)
function."""
n, x = asarray(n), asarray(x)
cond = (n==0)
fac2 = (-1.0)**(n+1) * gamma(n+1.0) * zeta(n+1,x)
if sometrue(cond,axis=0):
return where(cond, psi(x), fac2)
return fac2
def mathieu_even_coef(m,q):
"""Compute expansion coefficients for even mathieu functions and
modified mathieu functions.
"""
if not (isscalar(m) and isscalar(q)):
raise ValueError("m and q must be scalars.")
if (q < 0):
raise ValueError("q >=0")
if (m != floor(m)) or (m<0):
raise ValueError("m must be an integer >=0.")
if (q <= 1):
qm = 7.5+56.1*sqrt(q)-134.7*q+90.7*sqrt(q)*q
else:
qm=17.0+3.1*sqrt(q)-.126*q+.0037*sqrt(q)*q
km = int(qm+0.5*m)
if km > 251:
print "Warning, too many predicted coefficients."
kd = 1
m = int(floor(m))
if m % 2:
kd = 2
a = mathieu_a(m,q)
fc = specfun.fcoef(kd,m,q,a)
return fc[:km]
def mathieu_odd_coef(m,q):
"""Compute expansion coefficients for even mathieu functions and
modified mathieu functions.
"""
if not (isscalar(m) and isscalar(q)):
raise ValueError("m and q must be scalars.")
if (q < 0):
raise ValueError("q >=0")
if (m != floor(m)) or (m<=0):
raise ValueError("m must be an integer > 0")
if (q <= 1):
qm = 7.5+56.1*sqrt(q)-134.7*q+90.7*sqrt(q)*q
else:
qm=17.0+3.1*sqrt(q)-.126*q+.0037*sqrt(q)*q
km = int(qm+0.5*m)
if km > 251:
print "Warning, too many predicted coefficients."
kd = 4
m = int(floor(m))
if m % 2:
kd = 3
b = mathieu_b(m,q)
fc = specfun.fcoef(kd,m,q,b)
return fc[:km]
def lpmn(m,n,z):
"""Associated Legendre functions of the first kind, Pmn(z) and its
derivative, ``Pmn'(z)`` of order m and degree n. Returns two
arrays of size ``(m+1, n+1)`` containing ``Pmn(z)`` and ``Pmn'(z)`` for
all orders from ``0..m`` and degrees from ``0..n``.
Parameters
----------
m : int
``|m| <= n``; the order of the Legendre function.
n : int
where ``n >= 0``; the degree of the Legendre function. Often
called ``l`` (lower case L) in descriptions of the associated
Legendre function
z : float or complex
Input value.
Returns
-------
Pmn_z : (m+1, n+1) array
Values for all orders 0..m and degrees 0..n
Pmn_d_z : (m+1, n+1) array
Derivatives for all orders 0..m and degrees 0..n
"""
if not isscalar(m) or (abs(m)>n):
raise ValueError("m must be <= n.")
if not isscalar(n) or (n<0):
raise ValueError("n must be a non-negative integer.")
if not isscalar(z):
raise ValueError("z must be scalar.")
if (m < 0):
mp = -m
mf,nf = mgrid[0:mp+1,0:n+1]
sv = errprint(0)
fixarr = where(mf>nf,0.0,(-1)**mf * gamma(nf-mf+1) / gamma(nf+mf+1))
sv = errprint(sv)
else:
mp = m
if iscomplex(z):
p,pd = specfun.clpmn(mp,n,real(z),imag(z))
else:
p,pd = specfun.lpmn(mp,n,z)
if (m < 0):
p = p * fixarr
pd = pd * fixarr
return p,pd
def lqmn(m,n,z):
"""Associated Legendre functions of the second kind, Qmn(z) and its
derivative, ``Qmn'(z)`` of order m and degree n. Returns two
arrays of size ``(m+1, n+1)`` containing ``Qmn(z)`` and ``Qmn'(z)`` for
all orders from ``0..m`` and degrees from ``0..n``.
z can be complex.
"""
if not isscalar(m) or (m<0):
raise ValueError("m must be a non-negative integer.")
if not isscalar(n) or (n<0):
raise ValueError("n must be a non-negative integer.")
if not isscalar(z):
raise ValueError("z must be scalar.")
m = int(m)
n = int(n)
# Ensure neither m nor n == 0
mm = max(1,m)
nn = max(1,n)
if iscomplex(z):
q,qd = specfun.clqmn(mm,nn,z)
else:
q,qd = specfun.lqmn(mm,nn,z)
return q[:(m+1),:(n+1)],qd[:(m+1),:(n+1)]
def bernoulli(n):
"""Return an array of the Bernoulli numbers B0..Bn
"""
if not isscalar(n) or (n<0):
raise ValueError("n must be a non-negative integer.")
n = int(n)
if (n < 2): n1 = 2
else: n1 = n
return specfun.bernob(int(n1))[:(n+1)]
def euler(n):
"""Return an array of the Euler numbers E0..En (inclusive)
"""
if not isscalar(n) or (n<0):
raise ValueError("n must be a non-negative integer.")
n = int(n)
if (n < 2): n1 = 2
else: n1 = n
return specfun.eulerb(n1)[:(n+1)]
def lpn(n,z):
"""Compute sequence of Legendre functions of the first kind (polynomials),
Pn(z) and derivatives for all degrees from 0 to n (inclusive).
See also special.legendre for polynomial class.
"""
if not (isscalar(n) and isscalar(z)):
raise ValueError("arguments must be scalars.")
if (n!= floor(n)) or (n<0):
raise ValueError("n must be a non-negative integer.")
if (n < 1): n1 = 1
else: n1 = n
if iscomplex(z):
pn,pd = specfun.clpn(n1,z)
else:
pn,pd = specfun.lpn(n1,z)
return pn[:(n+1)],pd[:(n+1)]
## lpni
def lqn(n,z):
"""Compute sequence of Legendre functions of the second kind,
Qn(z) and derivatives for all degrees from 0 to n (inclusive).
"""
if not (isscalar(n) and isscalar(z)):
raise ValueError("arguments must be scalars.")
if (n!= floor(n)) or (n<0):
raise ValueError("n must be a non-negative integer.")
if (n < 1): n1 = 1
else: n1 = n
if iscomplex(z):
qn,qd = specfun.clqn(n1,z)
else:
qn,qd = specfun.lqnb(n1,z)
return qn[:(n+1)],qd[:(n+1)]
def ai_zeros(nt):
"""Compute the zeros of Airy Functions Ai(x) and Ai'(x), a and a'
respectively, and the associated values of Ai(a') and Ai'(a).
Returns
-------
a[l-1] -- the lth zero of Ai(x)
ap[l-1] -- the lth zero of Ai'(x)
ai[l-1] -- Ai(ap[l-1])
aip[l-1] -- Ai'(a[l-1])
"""
kf = 1
if not isscalar(nt) or (floor(nt)!=nt) or (nt<=0):
raise ValueError("nt must be a positive integer scalar.")
return specfun.airyzo(nt,kf)
def bi_zeros(nt):
"""Compute the zeros of Airy Functions Bi(x) and Bi'(x), b and b'
respectively, and the associated values of Ai(b') and Ai'(b).
Returns
-------
b[l-1] -- the lth zero of Bi(x)
bp[l-1] -- the lth zero of Bi'(x)
bi[l-1] -- Bi(bp[l-1])
bip[l-1] -- Bi'(b[l-1])
"""
kf = 2
if not isscalar(nt) or (floor(nt)!=nt) or (nt<=0):
raise ValueError("nt must be a positive integer scalar.")
return specfun.airyzo(nt,kf)
def lmbda(v,x):
"""Compute sequence of lambda functions with arbitrary order v
and their derivatives. Lv0(x)..Lv(x) are computed with v0=v-int(v).
"""
if not (isscalar(v) and isscalar(x)):
raise ValueError("arguments must be scalars.")
if (v<0):
raise ValueError("argument must be > 0.")
n = int(v)
v0 = v - n
if (n < 1): n1 = 1
else: n1 = n
v1 = n1 + v0
if (v!=floor(v)):
vm, vl, dl = specfun.lamv(v1,x)
else:
vm, vl, dl = specfun.lamn(v1,x)
return vl[:(n+1)], dl[:(n+1)]
def pbdv_seq(v,x):
"""Compute sequence of parabolic cylinder functions Dv(x) and
their derivatives for Dv0(x)..Dv(x) with v0=v-int(v).
"""
if not (isscalar(v) and isscalar(x)):
raise ValueError("arguments must be scalars.")
n = int(v)
v0 = v-n
if (n < 1): n1=1
else: n1 = n
v1 = n1 + v0
dv,dp,pdf,pdd = specfun.pbdv(v1,x)
return dv[:n1+1],dp[:n1+1]
def pbvv_seq(v,x):
"""Compute sequence of parabolic cylinder functions Dv(x) and
their derivatives for Dv0(x)..Dv(x) with v0=v-int(v).
"""
if not (isscalar(v) and isscalar(x)):
raise ValueError("arguments must be scalars.")
n = int(v)
v0 = v-n
if (n <= 1): n1=1
else: n1 = n
v1 = n1 + v0
dv,dp,pdf,pdd = specfun.pbvv(v1,x)
return dv[:n1+1],dp[:n1+1]
def pbdn_seq(n,z):
"""Compute sequence of parabolic cylinder functions Dn(z) and
their derivatives for D0(z)..Dn(z).
"""
if not (isscalar(n) and isscalar(z)):
raise ValueError("arguments must be scalars.")
if (floor(n)!=n):
raise ValueError("n must be an integer.")
if (abs(n) <= 1):
n1 = 1
else:
n1 = n
cpb,cpd = specfun.cpbdn(n1,z)
return cpb[:n1+1],cpd[:n1+1]
def ber_zeros(nt):
"""Compute nt zeros of the kelvin function ber x
"""
if not isscalar(nt) or (floor(nt)!=nt) or (nt<=0):
raise ValueError("nt must be positive integer scalar.")
return specfun.klvnzo(nt,1)
def bei_zeros(nt):
"""Compute nt zeros of the kelvin function bei x
"""
if not isscalar(nt) or (floor(nt)!=nt) or (nt<=0):
raise ValueError("nt must be positive integer scalar.")
return specfun.klvnzo(nt,2)
def ker_zeros(nt):
"""Compute nt zeros of the kelvin function ker x
"""
if not isscalar(nt) or (floor(nt)!=nt) or (nt<=0):
raise ValueError("nt must be positive integer scalar.")
return specfun.klvnzo(nt,3)
def kei_zeros(nt):
"""Compute nt zeros of the kelvin function kei x
"""
if not isscalar(nt) or (floor(nt)!=nt) or (nt<=0):
raise ValueError("nt must be positive integer scalar.")
return specfun.klvnzo(nt,4)
def berp_zeros(nt):
"""Compute nt zeros of the kelvin function ber' x
"""
if not isscalar(nt) or (floor(nt)!=nt) or (nt<=0):
raise ValueError("nt must be positive integer scalar.")
return specfun.klvnzo(nt,5)
def beip_zeros(nt):
"""Compute nt zeros of the kelvin function bei' x
"""
if not isscalar(nt) or (floor(nt)!=nt) or (nt<=0):
raise ValueError("nt must be positive integer scalar.")
return specfun.klvnzo(nt,6)
def kerp_zeros(nt):
"""Compute nt zeros of the kelvin function ker' x
"""
if not isscalar(nt) or (floor(nt)!=nt) or (nt<=0):
raise ValueError("nt must be positive integer scalar.")
return specfun.klvnzo(nt,7)
def keip_zeros(nt):
"""Compute nt zeros of the kelvin function kei' x
"""
if not isscalar(nt) or (floor(nt)!=nt) or (nt<=0):
raise ValueError("nt must be positive integer scalar.")
return specfun.klvnzo(nt,8)
def kelvin_zeros(nt):
"""Compute nt zeros of all the kelvin functions returned in a
length 8 tuple of arrays of length nt.
The tuple containse the arrays of zeros of
(ber, bei, ker, kei, ber', bei', ker', kei')
"""
if not isscalar(nt) or (floor(nt)!=nt) or (nt<=0):
raise ValueError("nt must be positive integer scalar.")
return specfun.klvnzo(nt,1), \
specfun.klvnzo(nt,2), \
specfun.klvnzo(nt,3), \
specfun.klvnzo(nt,4), \
specfun.klvnzo(nt,5), \
specfun.klvnzo(nt,6), \
specfun.klvnzo(nt,7), \
specfun.klvnzo(nt,8)
def pro_cv_seq(m,n,c):
"""Compute a sequence of characteristic values for the prolate
spheroidal wave functions for mode m and n'=m..n and spheroidal
parameter c.
"""
if not (isscalar(m) and isscalar(n) and isscalar(c)):
raise ValueError("Arguments must be scalars.")
if (n!=floor(n)) or (m!=floor(m)):
raise ValueError("Modes must be integers.")
if (n-m > 199):
raise ValueError("Difference between n and m is too large.")
maxL = n-m+1
return specfun.segv(m,n,c,1)[1][:maxL]
def obl_cv_seq(m,n,c):
"""Compute a sequence of characteristic values for the oblate
spheroidal wave functions for mode m and n'=m..n and spheroidal
parameter c.
"""
if not (isscalar(m) and isscalar(n) and isscalar(c)):
raise ValueError("Arguments must be scalars.")
if (n!=floor(n)) or (m!=floor(m)):
raise ValueError("Modes must be integers.")
if (n-m > 199):
raise ValueError("Difference between n and m is too large.")
maxL = n-m+1
return specfun.segv(m,n,c,-1)[1][:maxL]
def ellipk(m):
"""y=ellipk(m) returns the complete integral of the first kind:
integral(1/sqrt(1-m*sin(t)**2),t=0..pi/2)
This function is rather imprecise around m==1. For more precision
around this point, use ellipkm1."""
return ellipkm1(1 - asarray(m))
def agm(a,b):
"""Arithmetic, Geometric Mean
Start with a_0=a and b_0=b and iteratively compute
a_{n+1} = (a_n+b_n)/2
b_{n+1} = sqrt(a_n*b_n)
until a_n=b_n. The result is agm(a,b)
agm(a,b)=agm(b,a)
agm(a,a) = a
min(a,b) < agm(a,b) < max(a,b)
"""
s = a + b + 0.0
return (pi / 4) * s / ellipkm1(4 * a * b / s ** 2)