1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
|
/* @(#)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 <errno.h>
#include <math.h>
#include <math_private.h>
double
__tgamma(double x)
{
int local_signgam;
double y = __ieee754_gamma_r(x,&local_signgam);
if(__glibc_unlikely (!__finite (y) || y == 0)
&& (__finite (x) || __isinf (x) < 0)
&& _LIB_VERSION != _IEEE_) {
if (x == 0.0)
return __kernel_standard(x,x,50); /* tgamma pole */
else if(__floor(x)==x&&x<0.0)
return __kernel_standard(x,x,41); /* tgamma domain */
else if (y == 0)
__set_errno (ERANGE); /* tgamma underflow */
else
return __kernel_standard(x,x,40); /* tgamma overflow */
}
return local_signgam < 0 ? -y : y;
}
weak_alias (__tgamma, tgamma)
#ifdef NO_LONG_DOUBLE
strong_alias (__tgamma, __tgammal)
weak_alias (__tgamma, tgammal)
#endif
|
