You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
89 lines
2.4 KiB
89 lines
2.4 KiB
4 months ago
|
|
||
|
|
/* @(#)w_jn.c 1.3 95/01/18 */
|
||
|
|
/*
|
||
|
|
* ====================================================
|
||
|
|
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
|
||
|
|
*
|
||
|
|
* Developed at SunSoft, a Sun Microsystems, Inc. business.
|
||
|
|
* Permission to use, copy, modify, and distribute this
|
||
|
|
* software is freely granted, provided that this notice
|
||
|
|
* is preserved.
|
||
|
|
* ====================================================
|
||
|
|
*/
|
||
|
|
|
||
|
|
/*
|
||
|
|
* wrapper ieee_jn(int n, double x), ieee_yn(int n, double x)
|
||
|
|
* floating point Bessel's function of the 1st and 2nd kind
|
||
|
|
* of order n
|
||
|
|
*
|
||
|
|
* Special cases:
|
||
|
|
* y0(0)=ieee_y1(0)=ieee_yn(n,0) = -inf with division by zero signal;
|
||
|
|
* y0(-ve)=ieee_y1(-ve)=ieee_yn(n,-ve) are NaN with invalid signal.
|
||
|
|
* Note 2. About ieee_jn(n,x), ieee_yn(n,x)
|
||
|
|
* For n=0, ieee_j0(x) is called,
|
||
|
|
* for n=1, ieee_j1(x) is called,
|
||
|
|
* for n<x, forward recursion us used starting
|
||
|
|
* from values of ieee_j0(x) and ieee_j1(x).
|
||
|
|
* for n>x, a continued fraction approximation to
|
||
|
|
* j(n,x)/j(n-1,x) is evaluated and then backward
|
||
|
|
* recursion is used starting from a supposed value
|
||
|
|
* for j(n,x). The resulting value of j(0,x) is
|
||
|
|
* compared with the actual value to correct the
|
||
|
|
* supposed value of j(n,x).
|
||
|
|
*
|
||
|
|
* yn(n,x) is similar in all respects, except
|
||
|
|
* that forward recursion is used for all
|
||
|
|
* values of n>1.
|
||
|
|
*
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include "fdlibm.h"
|
||
|
|
|
||
|
|
#ifdef __STDC__
|
||
|
|
double ieee_jn(int n, double x) /* wrapper jn */
|
||
|
|
#else
|
||
|
|
double ieee_jn(n,x) /* wrapper jn */
|
||
|
|
double x; int n;
|
||
|
|
#endif
|
||
|
|
{
|
||
|
|
#ifdef _IEEE_LIBM
|
||
|
|
return __ieee754_jn(n,x);
|
||
|
|
#else
|
||
|
|
double z;
|
||
|
|
z = __ieee754_jn(n,x);
|
||
|
|
if(_LIB_VERSION == _IEEE_ || ieee_isnan(x) ) return z;
|
||
|
|
if(ieee_fabs(x)>X_TLOSS) {
|
||
|
|
return __kernel_standard((double)n,x,38); /* ieee_jn(|x|>X_TLOSS,n) */
|
||
|
|
} else
|
||
|
|
return z;
|
||
|
|
#endif
|
||
|
|
}
|
||
|
|
|
||
|
|
#ifdef __STDC__
|
||
|
|
double ieee_yn(int n, double x) /* wrapper yn */
|
||
|
|
#else
|
||
|
|
double ieee_yn(n,x) /* wrapper yn */
|
||
|
|
double x; int n;
|
||
|
|
#endif
|
||
|
|
{
|
||
|
|
#ifdef _IEEE_LIBM
|
||
|
|
return __ieee754_yn(n,x);
|
||
|
|
#else
|
||
|
|
double z;
|
||
|
|
z = __ieee754_yn(n,x);
|
||
|
|
if(_LIB_VERSION == _IEEE_ || ieee_isnan(x) ) return z;
|
||
|
|
if(x <= 0.0){
|
||
|
|
if(x==0.0)
|
||
|
|
/* d= -one/(x-x); */
|
||
|
|
return __kernel_standard((double)n,x,12);
|
||
|
|
else
|
||
|
|
/* d = zero/(x-x); */
|
||
|
|
return __kernel_standard((double)n,x,13);
|
||
|
|
}
|
||
|
|
if(x>X_TLOSS) {
|
||
|
|
return __kernel_standard((double)n,x,39); /* ieee_yn(x>X_TLOSS,n) */
|
||
|
|
} else
|
||
|
|
return z;
|
||
|
|
#endif
|
||
|
|
}
|