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[/] [openrisc/] [trunk/] [gnu-old/] [newlib-1.17.0/] [newlib/] [libm/] [math/] [w_j0.c] - Rev 148
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/* @(#)w_j0.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. * ==================================================== */ /* FUNCTION <<jN>>, <<jNf>>, <<yN>>, <<yNf>>---Bessel functions INDEX j0 INDEX j0f INDEX j1 INDEX j1f INDEX jn INDEX jnf INDEX y0 INDEX y0f INDEX y1 INDEX y1f INDEX yn INDEX ynf ANSI_SYNOPSIS #include <math.h> double j0(double <[x]>); float j0f(float <[x]>); double j1(double <[x]>); float j1f(float <[x]>); double jn(int <[n]>, double <[x]>); float jnf(int <[n]>, float <[x]>); double y0(double <[x]>); float y0f(float <[x]>); double y1(double <[x]>); float y1f(float <[x]>); double yn(int <[n]>, double <[x]>); float ynf(int <[n]>, float <[x]>); TRAD_SYNOPSIS #include <math.h> double j0(<[x]>) double <[x]>; float j0f(<[x]>) float <[x]>; double j1(<[x]>) double <[x]>; float j1f(<[x]>) float <[x]>; double jn(<[n]>, <[x]>) int <[n]>; double <[x]>; float jnf(<[n]>, <[x]>) int <[n]>; float <[x]>; double y0(<[x]>) double <[x]>; float y0f(<[x]>) float <[x]>; double y1(<[x]>) double <[x]>; float y1f(<[x]>) float <[x]>; double yn(<[n]>, <[x]>) int <[n]>; double <[x]>; float ynf(<[n]>, <[x]>) int <[n]>; float <[x]>; DESCRIPTION The Bessel functions are a family of functions that solve the differential equation @ifnottex . 2 2 2 . x y'' + xy' + (x - p )y = 0 @end ifnottex @tex $$x^2{d^2y\over dx^2} + x{dy\over dx} + (x^2-p^2)y = 0$$ @end tex These functions have many applications in engineering and physics. <<jn>> calculates the Bessel function of the first kind of order <[n]>. <<j0>> and <<j1>> are special cases for order 0 and order 1 respectively. Similarly, <<yn>> calculates the Bessel function of the second kind of order <[n]>, and <<y0>> and <<y1>> are special cases for order 0 and 1. <<jnf>>, <<j0f>>, <<j1f>>, <<ynf>>, <<y0f>>, and <<y1f>> perform the same calculations, but on <<float>> rather than <<double>> values. RETURNS The value of each Bessel function at <[x]> is returned. PORTABILITY None of the Bessel functions are in ANSI C. */ /* * wrapper j0(double x), y0(double x) */ #include "fdlibm.h" #include <errno.h> #ifndef _DOUBLE_IS_32BITS #ifdef __STDC__ double j0(double x) /* wrapper j0 */ #else double j0(x) /* wrapper j0 */ double x; #endif { #ifdef _IEEE_LIBM return __ieee754_j0(x); #else struct exception exc; double z = __ieee754_j0(x); if(_LIB_VERSION == _IEEE_ || isnan(x)) return z; if(fabs(x)>X_TLOSS) { /* j0(|x|>X_TLOSS) */ exc.type = TLOSS; exc.name = "j0"; exc.err = 0; exc.arg1 = 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 y0(double x) /* wrapper y0 */ #else double y0(x) /* wrapper y0 */ double x; #endif { #ifdef _IEEE_LIBM return __ieee754_y0(x); #else double z; struct exception exc; z = __ieee754_y0(x); if(_LIB_VERSION == _IEEE_ || isnan(x) ) return z; if(x <= 0.0){ #ifndef HUGE_VAL #define HUGE_VAL inf double inf = 0.0; SET_HIGH_WORD(inf,0x7ff00000); /* set inf to infinite */ #endif /* y0(0) = -inf or y0(x<0) = NaN */ exc.type = DOMAIN; /* should be SING for IEEE y0(0) */ exc.name = "y0"; exc.err = 0; exc.arg1 = 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) { /* y0(x>X_TLOSS) */ exc.type = TLOSS; exc.name = "y0"; exc.err = 0; exc.arg1 = 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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