| lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame] | 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 | |
| 50 | long double __jnl(int n, long double x) /* wrapper jnl */ |
| 51 | { |
| 52 | #ifdef _IEEE_LIBM |
| 53 | return __ieee754_jnl(n,x); |
| 54 | #else |
| 55 | long double z; |
| 56 | z = __ieee754_jnl(n,x); |
| 57 | if (_LIB_VERSION == _IEEE_ |
| 58 | || _LIB_VERSION == _POSIX_ |
| 59 | || isnan(x)) |
| 60 | return z; |
| 61 | if(fabsl(x)>X_TLOSS) { |
| 62 | return __kernel_standard_l((double)n,x,238); /* jn(|x|>X_TLOSS,n) */ |
| 63 | } else |
| 64 | return z; |
| 65 | #endif |
| 66 | } |
| 67 | weak_alias (__jnl, jnl) |
| 68 | |
| 69 | long double __ynl(int n, long double x) /* wrapper ynl */ |
| 70 | { |
| 71 | #ifdef _IEEE_LIBM |
| 72 | return __ieee754_ynl(n,x); |
| 73 | #else |
| 74 | long double z; |
| 75 | z = __ieee754_ynl(n,x); |
| 76 | if(_LIB_VERSION == _IEEE_ || isnan(x) ) return z; |
| 77 | if(x <= 0.0){ |
| 78 | if(x==0.0) |
| 79 | /* d= -one/(x-x); */ |
| 80 | return __kernel_standard_l((double)n,x,212); |
| 81 | else |
| 82 | /* d = zero/(x-x); */ |
| 83 | return __kernel_standard_l((double)n,x,213); |
| 84 | } |
| 85 | if(x>X_TLOSS && _LIB_VERSION != _POSIX_) { |
| 86 | return __kernel_standard_l((double)n,x,239); /* yn(x>X_TLOSS,n) */ |
| 87 | } else |
| 88 | return z; |
| 89 | #endif |
| 90 | } |
| 91 | weak_alias (__ynl, ynl) |