| |
| /* |
| * Copyright 1998-2001 Sun Microsystems, Inc. All Rights Reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Sun designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Sun in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| * CA 95054 USA or visit www.sun.com if you need additional information or |
| * have any questions. |
| */ |
| |
| /* |
| * wrapper jn(int n, double x), yn(int n, double x) |
| * floating point Bessel's function of the 1st and 2nd kind |
| * of order n |
| * |
| * Special cases: |
| * y0(0)=y1(0)=yn(n,0) = -inf with division by zero signal; |
| * y0(-ve)=y1(-ve)=yn(n,-ve) are NaN with invalid signal. |
| * Note 2. About jn(n,x), yn(n,x) |
| * For n=0, j0(x) is called, |
| * for n=1, j1(x) is called, |
| * for n<x, forward recursion us used starting |
| * from values of j0(x) and 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 jn(int n, double x) /* wrapper jn */ |
| #else |
| double 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_ || isnan(x) ) return z; |
| if(fabs(x)>X_TLOSS) { |
| return __kernel_standard((double)n,x,38); /* jn(|x|>X_TLOSS,n) */ |
| } else |
| return z; |
| #endif |
| } |
| |
| #ifdef __STDC__ |
| double yn(int n, double x) /* wrapper yn */ |
| #else |
| double 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_ || 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); /* yn(x>X_TLOSS,n) */ |
| } else |
| return z; |
| #endif |
| } |