5980be9b3c
This work is based in part on code from NetBSD libm, libc and kernel. The library is partly public domain and partly BSD-style licensed.
45 lines
1.2 KiB
C
45 lines
1.2 KiB
C
/* @(#)w_gamma.c 5.1 93/09/24 */
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/*
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* ====================================================
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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*
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* Developed at SunPro, a Sun Microsystems, Inc. business.
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* Permission to use, copy, modify, and distribute this
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* software is freely granted, provided that this notice
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* is preserved.
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* ====================================================
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*/
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#include <sys/cdefs.h>
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#if defined(LIBM_SCCS) && !defined(lint)
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__RCSID("$NetBSD: w_gamma.c,v 1.11 2002/05/26 22:02:00 wiz Exp $");
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#endif
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/* double gamma(double x)
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* Return the logarithm of the Gamma function of x.
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*
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* Method: call gamma_r
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*/
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#include "math.h"
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#include "math_private.h"
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double
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gamma(double x)
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{
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#ifdef _IEEE_LIBM
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return __ieee754_lgamma_r(x,&signgam);
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#else
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double y;
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y = __ieee754_lgamma_r(x,&signgam);
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if(_LIB_VERSION == _IEEE_) return y;
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if(!finite(y)&&finite(x)) {
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if(floor(x)==x&&x<=0.0)
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return __kernel_standard(x,x,41); /* gamma pole */
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else
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return __kernel_standard(x,x,40); /* gamma overflow */
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} else
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return y;
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#endif
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}
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