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[/] [openrisc/] [trunk/] [gnu-src/] [newlib-1.18.0/] [newlib/] [libm/] [math/] [w_jn.c] - Rev 232
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/* @(#)w_jn.c 5.1 93/09/24 */ /* * ==================================================== * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. * * Developed at SunPro, a Sun Microsystems, Inc. business. * Permission to use, copy, modify, and distribute this * software is freely granted, provided that this notice * is preserved. * ==================================================== */ /* * 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" #include <errno.h> #ifndef _DOUBLE_IS_32BITS #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; struct exception exc; z = __ieee754_jn(n,x); if(_LIB_VERSION == _IEEE_ || isnan(x) ) return z; if(fabs(x)>X_TLOSS) { /* jn(|x|>X_TLOSS) */ exc.type = TLOSS; exc.name = "jn"; exc.err = 0; exc.arg1 = n; exc.arg2 = x; exc.retval = 0.0; if (_LIB_VERSION == _POSIX_) errno = ERANGE; else if (!matherr(&exc)) { errno = ERANGE; } if (exc.err != 0) errno = exc.err; return exc.retval; } 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; struct exception exc; z = __ieee754_yn(n,x); if(_LIB_VERSION == _IEEE_ || isnan(x) ) return z; if(x <= 0.0){ /* yn(n,0) = -inf or yn(x<0) = NaN */ #ifndef HUGE_VAL #define HUGE_VAL inf double inf = 0.0; SET_HIGH_WORD(inf,0x7ff00000); /* set inf to infinite */ #endif exc.type = DOMAIN; /* should be SING for IEEE */ exc.name = "yn"; exc.err = 0; exc.arg1 = n; exc.arg2 = x; if (_LIB_VERSION == _SVID_) exc.retval = -HUGE; else exc.retval = -HUGE_VAL; if (_LIB_VERSION == _POSIX_) errno = EDOM; else if (!matherr(&exc)) { errno = EDOM; } if (exc.err != 0) errno = exc.err; return exc.retval; } if(x>X_TLOSS) { /* yn(x>X_TLOSS) */ exc.type = TLOSS; exc.name = "yn"; exc.err = 0; exc.arg1 = n; exc.arg2 = x; exc.retval = 0.0; if (_LIB_VERSION == _POSIX_) errno = ERANGE; else if (!matherr(&exc)) { errno = ERANGE; } if (exc.err != 0) errno = exc.err; return exc.retval; } else return z; #endif } #endif /* defined(_DOUBLE_IS_32BITS) */
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