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) 18static 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#ifdef __STDC__ 51 long double jnl(int n, long double x) /* wrapper jnl */ 52#else 53 long double jnl(n,x) /* wrapper jnl */ 54 long double x; int n; 55#endif 56{ 57#ifdef _IEEE_LIBM 58 return __ieee754_jnl(n,x); 59#else 60 long double z; 61 z = __ieee754_jnl(n,x); 62 if(_LIB_VERSION == _IEEE_ || __isnanl(x) ) return z; 63 if(fabsl(x)>X_TLOSS) { 64 return __kernel_standard((double)n,x,238); /* jn(|x|>X_TLOSS,n) */ 65 } else 66 return z; 67#endif 68} 69 70#ifdef __STDC__ 71 long double ynl(int n, long double x) /* wrapper ynl */ 72#else 73 long double ynl(n,x) /* wrapper ynl */ 74 long double x; int n; 75#endif 76{ 77#ifdef _IEEE_LIBM 78 return __ieee754_ynl(n,x); 79#else 80 long double z; 81 z = __ieee754_ynl(n,x); 82 if(_LIB_VERSION == _IEEE_ || __isnanl(x) ) return z; 83 if(x <= 0.0){ 84 if(x==0.0) 85 /* d= -one/(x-x); */ 86 return __kernel_standard((double)n,x,212); 87 else 88 /* d = zero/(x-x); */ 89 return __kernel_standard((double)n,x,213); 90 } 91 if(x>X_TLOSS) { 92 return __kernel_standard((double)n,x,239); /* yn(x>X_TLOSS,n) */ 93 } else 94 return z; 95#endif 96} 97