| The Android Open Source Project | b07e1d9 | 2009-03-03 19:29:30 -0800 | [diff] [blame] | 1 | |
| 2 | /* @(#)w_gamma.c 1.3 95/01/18 */ |
| 3 | /* |
| 4 | * ==================================================== |
| 5 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
| 6 | * |
| 7 | * Developed at SunSoft, a Sun Microsystems, Inc. business. |
| 8 | * Permission to use, copy, modify, and distribute this |
| 9 | * software is freely granted, provided that this notice |
| 10 | * is preserved. |
| 11 | * ==================================================== |
| 12 | * |
| 13 | */ |
| 14 | |
| 15 | /* double ieee_gamma(double x) |
| 16 | * Return the logarithm of the Gamma function of x. |
| 17 | * |
| 18 | * Method: call gamma_r |
| 19 | */ |
| 20 | |
| 21 | #include "fdlibm.h" |
| 22 | |
| 23 | extern int signgam; |
| 24 | |
| 25 | #ifdef __STDC__ |
| 26 | double ieee_gamma(double x) |
| 27 | #else |
| 28 | double ieee_gamma(x) |
| 29 | double x; |
| 30 | #endif |
| 31 | { |
| 32 | #ifdef _IEEE_LIBM |
| 33 | return __ieee754_gamma_r(x,&signgam); |
| 34 | #else |
| 35 | double y; |
| 36 | y = __ieee754_gamma_r(x,&signgam); |
| 37 | if(_LIB_VERSION == _IEEE_) return y; |
| 38 | if(!ieee_finite(y)&&ieee_finite(x)) { |
| 39 | if(ieee_floor(x)==x&&x<=0.0) |
| 40 | return __kernel_standard(x,x,41); /* gamma pole */ |
| 41 | else |
| 42 | return __kernel_standard(x,x,40); /* gamma overflow */ |
| 43 | } else |
| 44 | return y; |
| 45 | #endif |
| 46 | } |