1 | /* w_jnl.c -- long double version of w_jn.c. |
2 | * Conversion to long double by Ulrich Drepper, |
3 | * Cygnus Support, drepper@cygnus.com. |
4 | */ |
5 | |
6 | /* |
7 | * ==================================================== |
8 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
9 | * |
10 | * Developed at SunPro, a Sun Microsystems, Inc. business. |
11 | * Permission to use, copy, modify, and distribute this |
12 | * software is freely granted, provided that this notice |
13 | * is preserved. |
14 | * ==================================================== |
15 | */ |
16 | |
17 | #if defined(LIBM_SCCS) && !defined(lint) |
18 | static char rcsid[] = "$NetBSD: $" ; |
19 | #endif |
20 | |
21 | /* |
22 | * wrapper jn(int n, double x), yn(int n, double x) |
23 | * floating point Bessel's function of the 1st and 2nd kind |
24 | * of order n |
25 | * |
26 | * Special cases: |
27 | * y0(0)=y1(0)=yn(n,0) = -inf with division by zero signal; |
28 | * y0(-ve)=y1(-ve)=yn(n,-ve) are NaN with invalid signal. |
29 | * Note 2. About jn(n,x), yn(n,x) |
30 | * For n=0, j0(x) is called, |
31 | * for n=1, j1(x) is called, |
32 | * for n<x, forward recursion us used starting |
33 | * from values of j0(x) and j1(x). |
34 | * for n>x, a continued fraction approximation to |
35 | * j(n,x)/j(n-1,x) is evaluated and then backward |
36 | * recursion is used starting from a supposed value |
37 | * for j(n,x). The resulting value of j(0,x) is |
38 | * compared with the actual value to correct the |
39 | * supposed value of j(n,x). |
40 | * |
41 | * yn(n,x) is similar in all respects, except |
42 | * that forward recursion is used for all |
43 | * values of n>1. |
44 | * |
45 | */ |
46 | |
47 | #include <math.h> |
48 | #include <math_private.h> |
49 | #include <math-svid-compat.h> |
50 | #include <libm-alias-ldouble.h> |
51 | |
52 | #if LIBM_SVID_COMPAT |
53 | long double __jnl(int n, long double x) /* wrapper jnl */ |
54 | { |
55 | # ifdef _IEEE_LIBM |
56 | return __ieee754_jnl(n,x); |
57 | # else |
58 | long double z; |
59 | z = __ieee754_jnl(n,x); |
60 | if (_LIB_VERSION == _IEEE_ |
61 | || _LIB_VERSION == _POSIX_ |
62 | || isnan(x)) |
63 | return z; |
64 | if(fabsl(x)>X_TLOSS) { |
65 | return __kernel_standard_l((double)n,x,238); /* jn(|x|>X_TLOSS,n) */ |
66 | } else |
67 | return z; |
68 | # endif |
69 | } |
70 | libm_alias_ldouble (__jn, jn) |
71 | |
72 | long double __ynl(int n, long double x) /* wrapper ynl */ |
73 | { |
74 | # ifdef _IEEE_LIBM |
75 | return __ieee754_ynl(n,x); |
76 | # else |
77 | long double z; |
78 | z = __ieee754_ynl(n,x); |
79 | if(_LIB_VERSION == _IEEE_ || isnan(x) ) return z; |
80 | if(x <= 0.0){ |
81 | if(x==0.0) |
82 | /* d= -one/(x-x); */ |
83 | return __kernel_standard_l((double)n,x,212); |
84 | else |
85 | /* d = zero/(x-x); */ |
86 | return __kernel_standard_l((double)n,x,213); |
87 | } |
88 | if(x>X_TLOSS && _LIB_VERSION != _POSIX_) { |
89 | return __kernel_standard_l((double)n,x,239); /* yn(x>X_TLOSS,n) */ |
90 | } else |
91 | return z; |
92 | # endif |
93 | } |
94 | libm_alias_ldouble (__yn, yn) |
95 | #endif |
96 | |