[444] | 1 | |
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| 2 | /* @(#)w_atanh.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 | FUNCTION |
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| 16 | <<atanh>>, <<atanhf>>---inverse hyperbolic tangent |
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| 17 | |
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| 18 | INDEX |
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| 19 | atanh |
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| 20 | INDEX |
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| 21 | atanhf |
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| 22 | |
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| 23 | SYNOPSIS |
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| 24 | #include <math.h> |
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| 25 | double atanh(double <[x]>); |
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| 26 | float atanhf(float <[x]>); |
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| 27 | |
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| 28 | DESCRIPTION |
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| 29 | <<atanh>> calculates the inverse hyperbolic tangent of <[x]>. |
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| 30 | |
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| 31 | <<atanhf>> is identical, other than taking and returning |
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| 32 | <<float>> values. |
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| 33 | |
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| 34 | RETURNS |
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| 35 | <<atanh>> and <<atanhf>> return the calculated value. |
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| 36 | |
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| 37 | If |
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| 38 | @ifnottex |
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| 39 | |<[x]>| |
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| 40 | @end ifnottex |
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| 41 | @tex |
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| 42 | $|x|$ |
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| 43 | @end tex |
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| 44 | is greater than 1, the global <<errno>> is set to <<EDOM>> and |
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| 45 | the result is a NaN. A <<DOMAIN error>> is reported. |
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| 46 | |
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| 47 | If |
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| 48 | @ifnottex |
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| 49 | |<[x]>| |
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| 50 | @end ifnottex |
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| 51 | @tex |
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| 52 | $|x|$ |
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| 53 | @end tex |
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| 54 | is 1, the global <<errno>> is set to <<EDOM>>; and the result is |
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| 55 | infinity with the same sign as <<x>>. A <<SING error>> is reported. |
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| 56 | |
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| 57 | You can modify the error handling for these routines using |
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| 58 | <<matherr>>. |
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| 59 | |
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| 60 | PORTABILITY |
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| 61 | Neither <<atanh>> nor <<atanhf>> are ANSI C. |
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| 62 | |
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| 63 | QUICKREF |
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| 64 | atanh - pure |
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| 65 | atanhf - pure |
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| 66 | |
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| 67 | |
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| 68 | */ |
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| 69 | |
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| 70 | /* |
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| 71 | * wrapper atanh(x) |
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| 72 | */ |
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| 73 | |
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| 74 | #include "fdlibm.h" |
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| 75 | #include <errno.h> |
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| 76 | |
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| 77 | #ifndef _DOUBLE_IS_32BITS |
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| 78 | |
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| 79 | #ifdef __STDC__ |
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| 80 | double atanh(double x) /* wrapper atanh */ |
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| 81 | #else |
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| 82 | double atanh(x) /* wrapper atanh */ |
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| 83 | double x; |
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| 84 | #endif |
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| 85 | { |
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| 86 | #ifdef _IEEE_LIBM |
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| 87 | return __ieee754_atanh(x); |
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| 88 | #else |
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| 89 | double z,y; |
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| 90 | struct exception exc; |
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| 91 | z = __ieee754_atanh(x); |
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| 92 | if(_LIB_VERSION == _IEEE_ || isnan(x)) return z; |
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| 93 | y = fabs(x); |
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| 94 | if(y>=1.0) { |
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| 95 | if(y>1.0) { |
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| 96 | /* atanh(|x|>1) */ |
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| 97 | exc.type = DOMAIN; |
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| 98 | exc.name = "atanh"; |
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| 99 | exc.err = 0; |
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| 100 | exc.arg1 = exc.arg2 = x; |
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| 101 | exc.retval = 0.0/0.0; |
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| 102 | if (_LIB_VERSION == _POSIX_) |
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| 103 | errno = EDOM; |
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| 104 | else if (!matherr(&exc)) { |
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| 105 | errno = EDOM; |
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| 106 | } |
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| 107 | } else { |
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| 108 | /* atanh(|x|=1) */ |
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| 109 | exc.type = SING; |
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| 110 | exc.name = "atanh"; |
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| 111 | exc.err = 0; |
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| 112 | exc.arg1 = exc.arg2 = x; |
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| 113 | exc.retval = x/0.0; /* sign(x)*inf */ |
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| 114 | if (_LIB_VERSION == _POSIX_) |
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| 115 | errno = EDOM; |
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| 116 | else if (!matherr(&exc)) { |
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| 117 | errno = EDOM; |
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| 118 | } |
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| 119 | } |
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| 120 | if (exc.err != 0) |
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| 121 | errno = exc.err; |
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| 122 | return exc.retval; |
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| 123 | } else |
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| 124 | return z; |
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| 125 | #endif |
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| 126 | } |
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| 127 | |
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| 128 | #endif /* defined(_DOUBLE_IS_32BITS) */ |
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| 129 | |
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| 130 | |
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| 131 | |
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| 132 | |
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