forked from NIFTI-Imaging/nifti_clib
-
Notifications
You must be signed in to change notification settings - Fork 0
/
nifticdf.c
11106 lines (9918 loc) · 283 KB
/
nifticdf.c
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
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/************************************************************************/
/** Functions to compute cumulative distributions and their inverses **/
/** for the NIfTI-1 statistical types. Much of this code is taken **/
/** from other sources. In particular, the cdflib functions by **/
/** Brown and Lovato make up the bulk of this file. That code **/
/** was placed in the public domain. The code by K. Krishnamoorthy **/
/** is also released for unrestricted use. Finally, the other parts **/
/** of this file (by RW Cox) are released to the public domain. **/
/** **/
/** Most of this file comprises a set of "static" functions, to be **/
/** called by the user-level functions at the very end of the file. **/
/** At the end of the file is a simple main program to drive these **/
/** functions. **/
/** **/
/** To find the user-level functions, search forward for the string **/
/** "nifti_", which will be at about line 11000. **/
/************************************************************************/
/*****==============================================================*****/
/***** Neither the National Institutes of Health (NIH), the DFWG, *****/
/***** nor any of the members or employees of these institutions *****/
/***** imply any warranty of usefulness of this material for any *****/
/***** purpose, and do not assume any liability for damages, *****/
/***** incidental or otherwise, caused by any use of this document. *****/
/***** If these conditions are not acceptable, do not use this! *****/
/*****==============================================================*****/
/************************************************************************/
#include "nifti1.h" /* for the NIFTI_INTENT_* constants */
#include "nifticdf.h"
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <ctype.h>
#include <string.h>
/************************************************************************/
/************ Include all the cdflib functions here and now *************/
/************ [about 9900 lines of code below here] *************/
/************************************************************************/
/***=====================================================================***/
double algdiv(double *a,double *b)
/*
-----------------------------------------------------------------------
COMPUTATION OF LN(GAMMA(B)/GAMMA(A+B)) WHEN B .GE. 8
--------
IN THIS ALGORITHM, DEL(X) IS THE FUNCTION DEFINED BY
LN(GAMMA(X)) = (X - 0.5)*LN(X) - X + 0.5*LN(2*PI) + DEL(X).
-----------------------------------------------------------------------
*/
{
static double c0 = .833333333333333e-01;
static double c1 = -.277777777760991e-02;
static double c2 = .793650666825390e-03;
static double c3 = -.595202931351870e-03;
static double c4 = .837308034031215e-03;
static double c5 = -.165322962780713e-02;
static double algdiv,c,d,h,s11,s3,s5,s7,s9,t,u,v,w,x,x2,T1;
/*
..
.. Executable Statements ..
*/
if(*a <= *b) goto S10;
h = *b/ *a;
c = 1.0e0/(1.0e0+h);
x = h/(1.0e0+h);
d = *a+(*b-0.5e0);
goto S20;
S10:
h = *a/ *b;
c = h/(1.0e0+h);
x = 1.0e0/(1.0e0+h);
d = *b+(*a-0.5e0);
S20:
/*
SET SN = (1 - X**N)/(1 - X)
*/
x2 = x*x;
s3 = 1.0e0+(x+x2);
s5 = 1.0e0+(x+x2*s3);
s7 = 1.0e0+(x+x2*s5);
s9 = 1.0e0+(x+x2*s7);
s11 = 1.0e0+(x+x2*s9);
/*
SET W = DEL(B) - DEL(A + B)
*/
t = pow(1.0e0/ *b,2.0);
w = ((((c5*s11*t+c4*s9)*t+c3*s7)*t+c2*s5)*t+c1*s3)*t+c0;
w *= (c/ *b);
/*
COMBINE THE RESULTS
*/
T1 = *a/ *b;
u = d*alnrel(&T1);
v = *a*(log(*b)-1.0e0);
if(u <= v) goto S30;
algdiv = w-v-u;
return algdiv;
S30:
algdiv = w-u-v;
return algdiv;
} /* END */
/***=====================================================================***/
double alngam(double *x)
/*
**********************************************************************
double alngam(double *x)
double precision LN of the GAMma function
Function
Returns the natural logarithm of GAMMA(X).
Arguments
X --> value at which scaled log gamma is to be returned
X is DOUBLE PRECISION
Method
If X .le. 6.0, then use recursion to get X below 3
then apply rational approximation number 5236 of
Hart et al, Computer Approximations, John Wiley and
Sons, NY, 1968.
If X .gt. 6.0, then use recursion to get X to at least 12 and
then use formula 5423 of the same source.
**********************************************************************
*/
{
#define hln2pi 0.91893853320467274178e0
static double coef[5] = {
0.83333333333333023564e-1,-0.27777777768818808e-2,0.79365006754279e-3,
-0.594997310889e-3,0.8065880899e-3
};
static double scoefd[4] = {
0.62003838007126989331e2,0.9822521104713994894e1,-0.8906016659497461257e1,
0.1000000000000000000e1
};
static double scoefn[9] = {
0.62003838007127258804e2,0.36036772530024836321e2,0.20782472531792126786e2,
0.6338067999387272343e1,0.215994312846059073e1,0.3980671310203570498e0,
0.1093115956710439502e0,0.92381945590275995e-2,0.29737866448101651e-2
};
static int K1 = 9;
static int K3 = 4;
static int K5 = 5;
static double alngam,offset,prod,xx;
static int i,n;
static double T2,T4,T6;
/*
..
.. Executable Statements ..
*/
if(!(*x <= 6.0e0)) goto S70;
prod = 1.0e0;
xx = *x;
if(!(*x > 3.0e0)) goto S30;
S10:
if(!(xx > 3.0e0)) goto S20;
xx -= 1.0e0;
prod *= xx;
goto S10;
S30:
S20:
if(!(*x < 2.0e0)) goto S60;
S40:
if(!(xx < 2.0e0)) goto S50;
prod /= xx;
xx += 1.0e0;
goto S40;
S60:
S50:
T2 = xx-2.0e0;
T4 = xx-2.0e0;
alngam = devlpl(scoefn,&K1,&T2)/devlpl(scoefd,&K3,&T4);
/*
COMPUTE RATIONAL APPROXIMATION TO GAMMA(X)
*/
alngam *= prod;
alngam = log(alngam);
goto S110;
S70:
offset = hln2pi;
/*
IF NECESSARY MAKE X AT LEAST 12 AND CARRY CORRECTION IN OFFSET
*/
n = fifidint(12.0e0-*x);
if(!(n > 0)) goto S90;
prod = 1.0e0;
for(i=1; i<=n; i++) prod *= (*x+(double)(i-1));
offset -= log(prod);
xx = *x+(double)n;
goto S100;
S90:
xx = *x;
S100:
/*
COMPUTE POWER SERIES
*/
T6 = 1.0e0/pow(xx,2.0);
alngam = devlpl(coef,&K5,&T6)/xx;
alngam += (offset+(xx-0.5e0)*log(xx)-xx);
S110:
return alngam;
#undef hln2pi
} /* END */
/***=====================================================================***/
double alnrel(double *a)
/*
-----------------------------------------------------------------------
EVALUATION OF THE FUNCTION LN(1 + A)
-----------------------------------------------------------------------
*/
{
static double p1 = -.129418923021993e+01;
static double p2 = .405303492862024e+00;
static double p3 = -.178874546012214e-01;
static double q1 = -.162752256355323e+01;
static double q2 = .747811014037616e+00;
static double q3 = -.845104217945565e-01;
static double alnrel,t,t2,w,x;
/*
..
.. Executable Statements ..
*/
if(fabs(*a) > 0.375e0) goto S10;
t = *a/(*a+2.0e0);
t2 = t*t;
w = (((p3*t2+p2)*t2+p1)*t2+1.0e0)/(((q3*t2+q2)*t2+q1)*t2+1.0e0);
alnrel = 2.0e0*t*w;
return alnrel;
S10:
x = 1.e0+*a;
alnrel = log(x);
return alnrel;
} /* END */
/***=====================================================================***/
double apser(double *a,double *b,double *x,double *eps)
/*
-----------------------------------------------------------------------
APSER YIELDS THE INCOMPLETE BETA RATIO I(SUB(1-X))(B,A) FOR
A .LE. MIN(EPS,EPS*B), B*X .LE. 1, AND X .LE. 0.5. USED WHEN
A IS VERY SMALL. USE ONLY IF ABOVE INEQUALITIES ARE SATISFIED.
-----------------------------------------------------------------------
*/
{
static double g = .577215664901533e0;
static double apser,aj,bx,c,j,s,t,tol;
/*
..
.. Executable Statements ..
*/
bx = *b**x;
t = *x-bx;
if(*b**eps > 2.e-2) goto S10;
c = log(*x)+psi(b)+g+t;
goto S20;
S10:
c = log(bx)+g+t;
S20:
tol = 5.0e0**eps*fabs(c);
j = 1.0e0;
s = 0.0e0;
S30:
j += 1.0e0;
t *= (*x-bx/j);
aj = t/j;
s += aj;
if(fabs(aj) > tol) goto S30;
apser = -(*a*(c+s));
return apser;
} /* END */
/***=====================================================================***/
double basym(double *a,double *b,double *lambda,double *eps)
/*
-----------------------------------------------------------------------
ASYMPTOTIC EXPANSION FOR IX(A,B) FOR LARGE A AND B.
LAMBDA = (A + B)*Y - B AND EPS IS THE TOLERANCE USED.
IT IS ASSUMED THAT LAMBDA IS NONNEGATIVE AND THAT
A AND B ARE GREATER THAN OR EQUAL TO 15.
-----------------------------------------------------------------------
*/
{
static double e0 = 1.12837916709551e0;
static double e1 = .353553390593274e0;
static int num = 20;
/*
------------------------
****** NUM IS THE MAXIMUM VALUE THAT N CAN TAKE IN THE DO LOOP
ENDING AT STATEMENT 50. IT IS REQUIRED THAT NUM BE EVEN.
THE ARRAYS A0, B0, C, D HAVE DIMENSION NUM + 1.
------------------------
E0 = 2/SQRT(PI)
E1 = 2**(-3/2)
------------------------
*/
static int K3 = 1;
static double basym,bsum,dsum,f,h,h2,hn,j0,j1,r,r0,r1,s,sum,t,t0,t1,u,w,w0,z,z0,
z2,zn,znm1;
static int i,im1,imj,j,m,mm1,mmj,n,np1;
static double a0[21],b0[21],c[21],d[21],T1,T2;
/*
..
.. Executable Statements ..
*/
basym = 0.0e0;
if(*a >= *b) goto S10;
h = *a/ *b;
r0 = 1.0e0/(1.0e0+h);
r1 = (*b-*a)/ *b;
w0 = 1.0e0/sqrt(*a*(1.0e0+h));
goto S20;
S10:
h = *b/ *a;
r0 = 1.0e0/(1.0e0+h);
r1 = (*b-*a)/ *a;
w0 = 1.0e0/sqrt(*b*(1.0e0+h));
S20:
T1 = -(*lambda/ *a);
T2 = *lambda/ *b;
f = *a*rlog1(&T1)+*b*rlog1(&T2);
t = exp(-f);
if(t == 0.0e0) return basym;
z0 = sqrt(f);
z = 0.5e0*(z0/e1);
z2 = f+f;
a0[0] = 2.0e0/3.0e0*r1;
c[0] = -(0.5e0*a0[0]);
d[0] = -c[0];
j0 = 0.5e0/e0*erfc1(&K3,&z0);
j1 = e1;
sum = j0+d[0]*w0*j1;
s = 1.0e0;
h2 = h*h;
hn = 1.0e0;
w = w0;
znm1 = z;
zn = z2;
for(n=2; n<=num; n+=2) {
hn = h2*hn;
a0[n-1] = 2.0e0*r0*(1.0e0+h*hn)/((double)n+2.0e0);
np1 = n+1;
s += hn;
a0[np1-1] = 2.0e0*r1*s/((double)n+3.0e0);
for(i=n; i<=np1; i++) {
r = -(0.5e0*((double)i+1.0e0));
b0[0] = r*a0[0];
for(m=2; m<=i; m++) {
bsum = 0.0e0;
mm1 = m-1;
for(j=1; j<=mm1; j++) {
mmj = m-j;
bsum += (((double)j*r-(double)mmj)*a0[j-1]*b0[mmj-1]);
}
b0[m-1] = r*a0[m-1]+bsum/(double)m;
}
c[i-1] = b0[i-1]/((double)i+1.0e0);
dsum = 0.0e0;
im1 = i-1;
for(j=1; j<=im1; j++) {
imj = i-j;
dsum += (d[imj-1]*c[j-1]);
}
d[i-1] = -(dsum+c[i-1]);
}
j0 = e1*znm1+((double)n-1.0e0)*j0;
j1 = e1*zn+(double)n*j1;
znm1 = z2*znm1;
zn = z2*zn;
w = w0*w;
t0 = d[n-1]*w*j0;
w = w0*w;
t1 = d[np1-1]*w*j1;
sum += (t0+t1);
if(fabs(t0)+fabs(t1) <= *eps*sum) goto S80;
}
S80:
u = exp(-bcorr(a,b));
basym = e0*t*u*sum;
return basym;
} /* END */
/***=====================================================================***/
double bcorr(double *a0,double *b0)
/*
-----------------------------------------------------------------------
EVALUATION OF DEL(A0) + DEL(B0) - DEL(A0 + B0) WHERE
LN(GAMMA(A)) = (A - 0.5)*LN(A) - A + 0.5*LN(2*PI) + DEL(A).
IT IS ASSUMED THAT A0 .GE. 8 AND B0 .GE. 8.
-----------------------------------------------------------------------
*/
{
static double c0 = .833333333333333e-01;
static double c1 = -.277777777760991e-02;
static double c2 = .793650666825390e-03;
static double c3 = -.595202931351870e-03;
static double c4 = .837308034031215e-03;
static double c5 = -.165322962780713e-02;
static double bcorr,a,b,c,h,s11,s3,s5,s7,s9,t,w,x,x2;
/*
..
.. Executable Statements ..
*/
a = fifdmin1(*a0,*b0);
b = fifdmax1(*a0,*b0);
h = a/b;
c = h/(1.0e0+h);
x = 1.0e0/(1.0e0+h);
x2 = x*x;
/*
SET SN = (1 - X**N)/(1 - X)
*/
s3 = 1.0e0+(x+x2);
s5 = 1.0e0+(x+x2*s3);
s7 = 1.0e0+(x+x2*s5);
s9 = 1.0e0+(x+x2*s7);
s11 = 1.0e0+(x+x2*s9);
/*
SET W = DEL(B) - DEL(A + B)
*/
t = pow(1.0e0/b,2.0);
w = ((((c5*s11*t+c4*s9)*t+c3*s7)*t+c2*s5)*t+c1*s3)*t+c0;
w *= (c/b);
/*
COMPUTE DEL(A) + W
*/
t = pow(1.0e0/a,2.0);
bcorr = (((((c5*t+c4)*t+c3)*t+c2)*t+c1)*t+c0)/a+w;
return bcorr;
} /* END */
/***=====================================================================***/
double betaln(double *a0,double *b0)
/*
-----------------------------------------------------------------------
EVALUATION OF THE LOGARITHM OF THE BETA FUNCTION
-----------------------------------------------------------------------
E = 0.5*LN(2*PI)
--------------------------
*/
{
static double e = .918938533204673e0;
static double betaln,a,b,c,h,u,v,w,z;
static int i,n;
static double T1;
/*
..
.. Executable Statements ..
*/
a = fifdmin1(*a0,*b0);
b = fifdmax1(*a0,*b0);
if(a >= 8.0e0) goto S100;
if(a >= 1.0e0) goto S20;
/*
-----------------------------------------------------------------------
PROCEDURE WHEN A .LT. 1
-----------------------------------------------------------------------
*/
if(b >= 8.0e0) goto S10;
T1 = a+b;
betaln = gamln(&a)+(gamln(&b)-gamln(&T1));
return betaln;
S10:
betaln = gamln(&a)+algdiv(&a,&b);
return betaln;
S20:
/*
-----------------------------------------------------------------------
PROCEDURE WHEN 1 .LE. A .LT. 8
-----------------------------------------------------------------------
*/
if(a > 2.0e0) goto S40;
if(b > 2.0e0) goto S30;
betaln = gamln(&a)+gamln(&b)-gsumln(&a,&b);
return betaln;
S30:
w = 0.0e0;
if(b < 8.0e0) goto S60;
betaln = gamln(&a)+algdiv(&a,&b);
return betaln;
S40:
/*
REDUCTION OF A WHEN B .LE. 1000
*/
if(b > 1000.0e0) goto S80;
n = a-1.0e0;
w = 1.0e0;
for(i=1; i<=n; i++) {
a -= 1.0e0;
h = a/b;
w *= (h/(1.0e0+h));
}
w = log(w);
if(b < 8.0e0) goto S60;
betaln = w+gamln(&a)+algdiv(&a,&b);
return betaln;
S60:
/*
REDUCTION OF B WHEN B .LT. 8
*/
n = b-1.0e0;
z = 1.0e0;
for(i=1; i<=n; i++) {
b -= 1.0e0;
z *= (b/(a+b));
}
betaln = w+log(z)+(gamln(&a)+(gamln(&b)-gsumln(&a,&b)));
return betaln;
S80:
/*
REDUCTION OF A WHEN B .GT. 1000
*/
n = a-1.0e0;
w = 1.0e0;
for(i=1; i<=n; i++) {
a -= 1.0e0;
w *= (a/(1.0e0+a/b));
}
betaln = log(w)-(double)n*log(b)+(gamln(&a)+algdiv(&a,&b));
return betaln;
S100:
/*
-----------------------------------------------------------------------
PROCEDURE WHEN A .GE. 8
-----------------------------------------------------------------------
*/
w = bcorr(&a,&b);
h = a/b;
c = h/(1.0e0+h);
u = -((a-0.5e0)*log(c));
v = b*alnrel(&h);
if(u <= v) goto S110;
betaln = -(0.5e0*log(b))+e+w-v-u;
return betaln;
S110:
betaln = -(0.5e0*log(b))+e+w-u-v;
return betaln;
} /* END */
/***=====================================================================***/
double bfrac(double *a,double *b,double *x,double *y,double *lambda,
double *eps)
/*
-----------------------------------------------------------------------
CONTINUED FRACTION EXPANSION FOR IX(A,B) WHEN A,B .GT. 1.
IT IS ASSUMED THAT LAMBDA = (A + B)*Y - B.
-----------------------------------------------------------------------
*/
{
static double bfrac,alpha,an,anp1,beta,bn,bnp1,c,c0,c1,e,n,p,r,r0,s,t,w,yp1;
/*
..
.. Executable Statements ..
*/
bfrac = brcomp(a,b,x,y);
if(bfrac == 0.0e0) return bfrac;
c = 1.0e0+*lambda;
c0 = *b/ *a;
c1 = 1.0e0+1.0e0/ *a;
yp1 = *y+1.0e0;
n = 0.0e0;
p = 1.0e0;
s = *a+1.0e0;
an = 0.0e0;
bn = anp1 = 1.0e0;
bnp1 = c/c1;
r = c1/c;
S10:
/*
CONTINUED FRACTION CALCULATION
*/
n += 1.0e0;
t = n/ *a;
w = n*(*b-n)**x;
e = *a/s;
alpha = p*(p+c0)*e*e*(w**x);
e = (1.0e0+t)/(c1+t+t);
beta = n+w/s+e*(c+n*yp1);
p = 1.0e0+t;
s += 2.0e0;
/*
UPDATE AN, BN, ANP1, AND BNP1
*/
t = alpha*an+beta*anp1;
an = anp1;
anp1 = t;
t = alpha*bn+beta*bnp1;
bn = bnp1;
bnp1 = t;
r0 = r;
r = anp1/bnp1;
if(fabs(r-r0) <= *eps*r) goto S20;
/*
RESCALE AN, BN, ANP1, AND BNP1
*/
an /= bnp1;
bn /= bnp1;
anp1 = r;
bnp1 = 1.0e0;
goto S10;
S20:
/*
TERMINATION
*/
bfrac *= r;
return bfrac;
} /* END */
/***=====================================================================***/
void bgrat(double *a,double *b,double *x,double *y,double *w,
double *eps,int *ierr)
/*
-----------------------------------------------------------------------
ASYMPTOTIC EXPANSION FOR IX(A,B) WHEN A IS LARGER THAN B.
THE RESULT OF THE EXPANSION IS ADDED TO W. IT IS ASSUMED
THAT A .GE. 15 AND B .LE. 1. EPS IS THE TOLERANCE USED.
IERR IS A VARIABLE THAT REPORTS THE STATUS OF THE RESULTS.
-----------------------------------------------------------------------
*/
{
static double bm1,bp2n,cn,coef,dj,j,l,lnx,n2,nu,p,q,r,s,sum,t,t2,u,v,z;
static int i,n,nm1;
static double c[30],d[30],T1;
/*
..
.. Executable Statements ..
*/
bm1 = *b-0.5e0-0.5e0;
nu = *a+0.5e0*bm1;
if(*y > 0.375e0) goto S10;
T1 = -*y;
lnx = alnrel(&T1);
goto S20;
S10:
lnx = log(*x);
S20:
z = -(nu*lnx);
if(*b*z == 0.0e0) goto S70;
/*
COMPUTATION OF THE EXPANSION
SET R = EXP(-Z)*Z**B/GAMMA(B)
*/
r = *b*(1.0e0+gam1(b))*exp(*b*log(z));
r *= (exp(*a*lnx)*exp(0.5e0*bm1*lnx));
u = algdiv(b,a)+*b*log(nu);
u = r*exp(-u);
if(u == 0.0e0) goto S70;
grat1(b,&z,&r,&p,&q,eps);
v = 0.25e0*pow(1.0e0/nu,2.0);
t2 = 0.25e0*lnx*lnx;
l = *w/u;
j = q/r;
sum = j;
t = cn = 1.0e0;
n2 = 0.0e0;
for(n=1; n<=30; n++) {
bp2n = *b+n2;
j = (bp2n*(bp2n+1.0e0)*j+(z+bp2n+1.0e0)*t)*v;
n2 += 2.0e0;
t *= t2;
cn /= (n2*(n2+1.0e0));
c[n-1] = cn;
s = 0.0e0;
if(n == 1) goto S40;
nm1 = n-1;
coef = *b-(double)n;
for(i=1; i<=nm1; i++) {
s += (coef*c[i-1]*d[n-i-1]);
coef += *b;
}
S40:
d[n-1] = bm1*cn+s/(double)n;
dj = d[n-1]*j;
sum += dj;
if(sum <= 0.0e0) goto S70;
if(fabs(dj) <= *eps*(sum+l)) goto S60;
}
S60:
/*
ADD THE RESULTS TO W
*/
*ierr = 0;
*w += (u*sum);
return;
S70:
/*
THE EXPANSION CANNOT BE COMPUTED
*/
*ierr = 1;
return;
} /* END */
/***=====================================================================***/
double bpser(double *a,double *b,double *x,double *eps)
/*
-----------------------------------------------------------------------
POWER SERIES EXPANSION FOR EVALUATING IX(A,B) WHEN B .LE. 1
OR B*X .LE. 0.7. EPS IS THE TOLERANCE USED.
-----------------------------------------------------------------------
*/
{
static double bpser,a0,apb,b0,c,n,sum,t,tol,u,w,z;
static int i,m;
/*
..
.. Executable Statements ..
*/
bpser = 0.0e0;
if(*x == 0.0e0) return bpser;
/*
-----------------------------------------------------------------------
COMPUTE THE FACTOR X**A/(A*BETA(A,B))
-----------------------------------------------------------------------
*/
a0 = fifdmin1(*a,*b);
if(a0 < 1.0e0) goto S10;
z = *a*log(*x)-betaln(a,b);
bpser = exp(z)/ *a;
goto S100;
S10:
b0 = fifdmax1(*a,*b);
if(b0 >= 8.0e0) goto S90;
if(b0 > 1.0e0) goto S40;
/*
PROCEDURE FOR A0 .LT. 1 AND B0 .LE. 1
*/
bpser = pow(*x,*a);
if(bpser == 0.0e0) return bpser;
apb = *a+*b;
if(apb > 1.0e0) goto S20;
z = 1.0e0+gam1(&apb);
goto S30;
S20:
u = *a+*b-1.e0;
z = (1.0e0+gam1(&u))/apb;
S30:
c = (1.0e0+gam1(a))*(1.0e0+gam1(b))/z;
bpser *= (c*(*b/apb));
goto S100;
S40:
/*
PROCEDURE FOR A0 .LT. 1 AND 1 .LT. B0 .LT. 8
*/
u = gamln1(&a0);
m = b0-1.0e0;
if(m < 1) goto S60;
c = 1.0e0;
for(i=1; i<=m; i++) {
b0 -= 1.0e0;
c *= (b0/(a0+b0));
}
u = log(c)+u;
S60:
z = *a*log(*x)-u;
b0 -= 1.0e0;
apb = a0+b0;
if(apb > 1.0e0) goto S70;
t = 1.0e0+gam1(&apb);
goto S80;
S70:
u = a0+b0-1.e0;
t = (1.0e0+gam1(&u))/apb;
S80:
bpser = exp(z)*(a0/ *a)*(1.0e0+gam1(&b0))/t;
goto S100;
S90:
/*
PROCEDURE FOR A0 .LT. 1 AND B0 .GE. 8
*/
u = gamln1(&a0)+algdiv(&a0,&b0);
z = *a*log(*x)-u;
bpser = a0/ *a*exp(z);
S100:
if(bpser == 0.0e0 || *a <= 0.1e0**eps) return bpser;
/*
-----------------------------------------------------------------------
COMPUTE THE SERIES
-----------------------------------------------------------------------
*/
sum = n = 0.0e0;
c = 1.0e0;
tol = *eps/ *a;
S110:
n += 1.0e0;
c *= ((0.5e0+(0.5e0-*b/n))**x);
w = c/(*a+n);
sum += w;
if(fabs(w) > tol) goto S110;
bpser *= (1.0e0+*a*sum);
return bpser;
} /* END */
/***=====================================================================***/
void bratio(double *a,double *b,double *x,double *y,double *w,
double *w1,int *ierr)
/*
-----------------------------------------------------------------------
EVALUATION OF THE INCOMPLETE BETA FUNCTION IX(A,B)
--------------------
IT IS ASSUMED THAT A AND B ARE NONNEGATIVE, AND THAT X .LE. 1
AND Y = 1 - X. BRATIO ASSIGNS W AND W1 THE VALUES
W = IX(A,B)
W1 = 1 - IX(A,B)
IERR IS A VARIABLE THAT REPORTS THE STATUS OF THE RESULTS.
IF NO INPUT ERRORS ARE DETECTED THEN IERR IS SET TO 0 AND
W AND W1 ARE COMPUTED. OTHERWISE, IF AN ERROR IS DETECTED,
THEN W AND W1 ARE ASSIGNED THE VALUE 0 AND IERR IS SET TO
ONE OF THE FOLLOWING VALUES ...
IERR = 1 IF A OR B IS NEGATIVE
IERR = 2 IF A = B = 0
IERR = 3 IF X .LT. 0 OR X .GT. 1
IERR = 4 IF Y .LT. 0 OR Y .GT. 1
IERR = 5 IF X + Y .NE. 1
IERR = 6 IF X = A = 0
IERR = 7 IF Y = B = 0
--------------------
WRITTEN BY ALFRED H. MORRIS, JR.
NAVAL SURFACE WARFARE CENTER
DAHLGREN, VIRGINIA
REVISED ... NOV 1991
-----------------------------------------------------------------------
*/
{
static int K1 = 1;
static double a0,b0,eps,lambda,t,x0,y0,z;
static int ierr1,ind,n;
static double T2,T3,T4,T5;
/*
..
.. Executable Statements ..
*/
/*
****** EPS IS A MACHINE DEPENDENT CONSTANT. EPS IS THE SMALLEST
FLOATING POINT NUMBER FOR WHICH 1.0 + EPS .GT. 1.0
*/
eps = spmpar(&K1);
*w = *w1 = 0.0e0;
if(*a < 0.0e0 || *b < 0.0e0) goto S270;
if(*a == 0.0e0 && *b == 0.0e0) goto S280;
if(*x < 0.0e0 || *x > 1.0e0) goto S290;
if(*y < 0.0e0 || *y > 1.0e0) goto S300;
z = *x+*y-0.5e0-0.5e0;
if(fabs(z) > 3.0e0*eps) goto S310;
*ierr = 0;
if(*x == 0.0e0) goto S210;
if(*y == 0.0e0) goto S230;
if(*a == 0.0e0) goto S240;
if(*b == 0.0e0) goto S220;
eps = fifdmax1(eps,1.e-15);
if(fifdmax1(*a,*b) < 1.e-3*eps) goto S260;
ind = 0;
a0 = *a;
b0 = *b;
x0 = *x;
y0 = *y;
if(fifdmin1(a0,b0) > 1.0e0) goto S40;
/*
PROCEDURE FOR A0 .LE. 1 OR B0 .LE. 1
*/
if(*x <= 0.5e0) goto S10;
ind = 1;
a0 = *b;
b0 = *a;
x0 = *y;
y0 = *x;
S10:
if(b0 < fifdmin1(eps,eps*a0)) goto S90;
if(a0 < fifdmin1(eps,eps*b0) && b0*x0 <= 1.0e0) goto S100;
if(fifdmax1(a0,b0) > 1.0e0) goto S20;
if(a0 >= fifdmin1(0.2e0,b0)) goto S110;
if(pow(x0,a0) <= 0.9e0) goto S110;
if(x0 >= 0.3e0) goto S120;
n = 20;
goto S140;
S20:
if(b0 <= 1.0e0) goto S110;
if(x0 >= 0.3e0) goto S120;
if(x0 >= 0.1e0) goto S30;
if(pow(x0*b0,a0) <= 0.7e0) goto S110;
S30:
if(b0 > 15.0e0) goto S150;
n = 20;
goto S140;
S40:
/*
PROCEDURE FOR A0 .GT. 1 AND B0 .GT. 1
*/
if(*a > *b) goto S50;
lambda = *a-(*a+*b)**x;
goto S60;
S50:
lambda = (*a+*b)**y-*b;
S60:
if(lambda >= 0.0e0) goto S70;
ind = 1;
a0 = *b;
b0 = *a;
x0 = *y;
y0 = *x;
lambda = fabs(lambda);
S70:
if(b0 < 40.0e0 && b0*x0 <= 0.7e0) goto S110;
if(b0 < 40.0e0) goto S160;
if(a0 > b0) goto S80;
if(a0 <= 100.0e0) goto S130;
if(lambda > 0.03e0*a0) goto S130;
goto S200;
S80:
if(b0 <= 100.0e0) goto S130;
if(lambda > 0.03e0*b0) goto S130;
goto S200;
S90:
/*
EVALUATION OF THE APPROPRIATE ALGORITHM
*/
*w = fpser(&a0,&b0,&x0,&eps);
*w1 = 0.5e0+(0.5e0-*w);
goto S250;
S100:
*w1 = apser(&a0,&b0,&x0,&eps);
*w = 0.5e0+(0.5e0-*w1);
goto S250;
S110:
*w = bpser(&a0,&b0,&x0,&eps);
*w1 = 0.5e0+(0.5e0-*w);
goto S250;
S120:
*w1 = bpser(&b0,&a0,&y0,&eps);
*w = 0.5e0+(0.5e0-*w1);
goto S250;
S130:
T2 = 15.0e0*eps;
*w = bfrac(&a0,&b0,&x0,&y0,&lambda,&T2);
*w1 = 0.5e0+(0.5e0-*w);
goto S250;
S140:
*w1 = bup(&b0,&a0,&y0,&x0,&n,&eps);
b0 += (double)n;
S150:
T3 = 15.0e0*eps;
bgrat(&b0,&a0,&y0,&x0,w1,&T3,&ierr1);
*w = 0.5e0+(0.5e0-*w1);
goto S250;
S160:
n = b0;
b0 -= (double)n;
if(b0 != 0.0e0) goto S170;
n -= 1;
b0 = 1.0e0;
S170:
*w = bup(&b0,&a0,&y0,&x0,&n,&eps);
if(x0 > 0.7e0) goto S180;
*w += bpser(&a0,&b0,&x0,&eps);
*w1 = 0.5e0+(0.5e0-*w);
goto S250;
S180:
if(a0 > 15.0e0) goto S190;
n = 20;
*w += bup(&a0,&b0,&x0,&y0,&n,&eps);
a0 += (double)n;
S190:
T4 = 15.0e0*eps;
bgrat(&a0,&b0,&x0,&y0,w,&T4,&ierr1);
*w1 = 0.5e0+(0.5e0-*w);
goto S250;
S200:
T5 = 100.0e0*eps;
*w = basym(&a0,&b0,&lambda,&T5);
*w1 = 0.5e0+(0.5e0-*w);
goto S250;
S210:
/*
TERMINATION OF THE PROCEDURE