mirror of
https://github.com/autc04/Retro68.git
synced 2024-12-01 11:52:47 +00:00
54 lines
1.2 KiB
C
54 lines
1.2 KiB
C
/* @(#)w_gamma.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.
|
|
* ====================================================
|
|
*/
|
|
|
|
/* double gamma(double x)
|
|
* Return the logarithm of the Gamma function of x or the Gamma function of x,
|
|
* depending on the library mode.
|
|
*/
|
|
|
|
#include <math.h>
|
|
#include <errno.h>
|
|
|
|
#ifdef __STDC__
|
|
double tgamma(double x)
|
|
#else
|
|
double tgamma(x)
|
|
double x;
|
|
#endif
|
|
{
|
|
double y;
|
|
int local_signgam;
|
|
y = gamma_r(x,&local_signgam);
|
|
if (local_signgam < 0) y = -y;
|
|
#ifdef _IEEE_LIBM
|
|
return y;
|
|
#else
|
|
if(_LIB_VERSION == _IEEE_) return y;
|
|
|
|
if(!finite(y)&&finite(x)) {
|
|
if(floor(x)==x&&x<=0.0)
|
|
{
|
|
/* tgamma pole */
|
|
errno = EDOM;
|
|
return HUGE_VAL;
|
|
}
|
|
else
|
|
{
|
|
/* tgamma overflow */
|
|
errno = ERANGE;
|
|
return HUGE_VAL;
|
|
}
|
|
}
|
|
return y;
|
|
#endif
|
|
}
|