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| 2 | /* @(#)w_lgamma.c 5.1 93/09/24 */ |
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| 3 | /* |
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| 4 | * ==================================================== |
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| 5 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
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| 6 | * |
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| 7 | * Developed at SunPro, a Sun Microsystems, Inc. business. |
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| 8 | * Permission to use, copy, modify, and distribute this |
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| 9 | * software is freely granted, provided that this notice |
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| 10 | * is preserved. |
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| 11 | * ==================================================== |
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| 12 | * |
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| 13 | */ |
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| 14 | |
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| 15 | /* double lgamma(double x) |
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| 16 | * Return the logarithm of the Gamma function of x. |
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| 17 | * |
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| 18 | * Method: call __ieee754_lgamma_r |
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| 19 | */ |
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| 20 | |
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| 21 | #include "fdlibm.h" |
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| 22 | #include <reent.h> |
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| 23 | #include <errno.h> |
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| 24 | |
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| 25 | #ifndef _DOUBLE_IS_32BITS |
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| 26 | |
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| 27 | #ifdef __STDC__ |
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| 28 | double lgamma(double x) |
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| 29 | #else |
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| 30 | double lgamma(x) |
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| 31 | double x; |
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| 32 | #endif |
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| 33 | { |
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| 34 | #ifdef _IEEE_LIBM |
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| 35 | return __ieee754_lgamma_r(x,&(_REENT_SIGNGAM(_REENT))); |
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| 36 | #else |
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| 37 | double y; |
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| 38 | struct exception exc; |
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| 39 | y = __ieee754_lgamma_r(x,&(_REENT_SIGNGAM(_REENT))); |
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| 40 | if(_LIB_VERSION == _IEEE_) return y; |
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| 41 | if(!finite(y)&&finite(x)) { |
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| 42 | #ifndef HUGE_VAL |
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| 43 | #define HUGE_VAL inf |
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| 44 | double inf = 0.0; |
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| 45 | |
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| 46 | SET_HIGH_WORD(inf,0x7ff00000); /* set inf to infinite */ |
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| 47 | #endif |
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| 48 | exc.name = "lgamma"; |
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| 49 | exc.err = 0; |
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| 50 | exc.arg1 = x; |
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| 51 | exc.arg2 = x; |
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| 52 | if (_LIB_VERSION == _SVID_) |
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| 53 | exc.retval = HUGE; |
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| 54 | else |
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| 55 | exc.retval = HUGE_VAL; |
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| 56 | if(floor(x)==x&&x<=0.0) { |
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| 57 | /* lgamma(-integer) */ |
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| 58 | exc.type = SING; |
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| 59 | if (_LIB_VERSION == _POSIX_) |
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| 60 | errno = EDOM; |
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| 61 | else if (!matherr(&exc)) { |
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| 62 | errno = EDOM; |
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| 63 | } |
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| 64 | |
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| 65 | } else { |
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| 66 | /* lgamma(finite) overflow */ |
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| 67 | exc.type = OVERFLOW; |
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| 68 | if (_LIB_VERSION == _POSIX_) |
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| 69 | errno = ERANGE; |
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| 70 | else if (!matherr(&exc)) { |
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| 71 | errno = ERANGE; |
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| 72 | } |
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| 73 | } |
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| 74 | if (exc.err != 0) |
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| 75 | errno = exc.err; |
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| 76 | return exc.retval; |
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| 77 | } else |
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| 78 | return y; |
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| 79 | #endif |
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| 80 | } |
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| 81 | |
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| 82 | #endif /* defined(_DOUBLE_IS_32BITS) */ |
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