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