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Diffstat (limited to 'libm/double/atanh.c')
-rw-r--r-- | libm/double/atanh.c | 156 |
1 files changed, 0 insertions, 156 deletions
diff --git a/libm/double/atanh.c b/libm/double/atanh.c deleted file mode 100644 index 7bb742d3d..000000000 --- a/libm/double/atanh.c +++ /dev/null @@ -1,156 +0,0 @@ -/* atanh.c - * - * Inverse hyperbolic tangent - * - * - * - * SYNOPSIS: - * - * double x, y, atanh(); - * - * y = atanh( x ); - * - * - * - * DESCRIPTION: - * - * Returns inverse hyperbolic tangent of argument in the range - * MINLOG to MAXLOG. - * - * If |x| < 0.5, the rational form x + x**3 P(x)/Q(x) is - * employed. Otherwise, - * atanh(x) = 0.5 * log( (1+x)/(1-x) ). - * - * - * - * ACCURACY: - * - * Relative error: - * arithmetic domain # trials peak rms - * DEC -1,1 50000 2.4e-17 6.4e-18 - * IEEE -1,1 30000 1.9e-16 5.2e-17 - * - */ - -/* atanh.c */ - - -/* -Cephes Math Library Release 2.8: June, 2000 -Copyright (C) 1987, 1995, 2000 by Stephen L. Moshier -*/ - -#include <math.h> - -#ifdef UNK -static double P[] = { --8.54074331929669305196E-1, - 1.20426861384072379242E1, --4.61252884198732692637E1, - 6.54566728676544377376E1, --3.09092539379866942570E1 -}; -static double Q[] = { -/* 1.00000000000000000000E0,*/ --1.95638849376911654834E1, - 1.08938092147140262656E2, --2.49839401325893582852E2, - 2.52006675691344555838E2, --9.27277618139601130017E1 -}; -#endif -#ifdef DEC -static unsigned short P[] = { -0140132,0122235,0105775,0130300, -0041100,0127327,0124407,0034722, -0141470,0100113,0115607,0130535, -0041602,0164721,0003257,0013673, -0141367,0043046,0166673,0045750 -}; -static unsigned short Q[] = { -/*0040200,0000000,0000000,0000000,*/ -0141234,0101326,0015460,0134564, -0041731,0160115,0116451,0032045, -0142171,0153343,0000532,0167226, -0042174,0000665,0077604,0000310, -0141671,0072235,0031114,0074377 -}; -#endif - -#ifdef IBMPC -static unsigned short P[] = { -0xb618,0xb17f,0x5493,0xbfeb, -0xe73a,0xf520,0x15da,0x4028, -0xf62c,0x7370,0x1009,0xc047, -0xe2f7,0x20d5,0x5d3a,0x4050, -0x697d,0xddb7,0xe8c4,0xc03e -}; -static unsigned short Q[] = { -/*0x0000,0x0000,0x0000,0x3ff0,*/ -0x172f,0xc366,0x905a,0xc033, -0x2685,0xb3a5,0x3c09,0x405b, -0x5dd3,0x602b,0x3adc,0xc06f, -0x8019,0xaff0,0x8036,0x406f, -0x8f20,0xa649,0x2e93,0xc057 -}; -#endif - -#ifdef MIEEE -static unsigned short P[] = { -0xbfeb,0x5493,0xb17f,0xb618, -0x4028,0x15da,0xf520,0xe73a, -0xc047,0x1009,0x7370,0xf62c, -0x4050,0x5d3a,0x20d5,0xe2f7, -0xc03e,0xe8c4,0xddb7,0x697d -}; -static unsigned short Q[] = { -0xc033,0x905a,0xc366,0x172f, -0x405b,0x3c09,0xb3a5,0x2685, -0xc06f,0x3adc,0x602b,0x5dd3, -0x406f,0x8036,0xaff0,0x8019, -0xc057,0x2e93,0xa649,0x8f20 -}; -#endif - -#ifdef ANSIPROT -extern double fabs ( double ); -extern double log ( double x ); -extern double polevl ( double x, void *P, int N ); -extern double p1evl ( double x, void *P, int N ); -#else -double fabs(), log(), polevl(), p1evl(); -#endif -extern double INFINITY, NAN; - -double atanh(x) -double x; -{ -double s, z; - -#ifdef MINUSZERO -if( x == 0.0 ) - return(x); -#endif -z = fabs(x); -if( z >= 1.0 ) - { - if( x == 1.0 ) - return( INFINITY ); - if( x == -1.0 ) - return( -INFINITY ); - mtherr( "atanh", DOMAIN ); - return( NAN ); - } - -if( z < 1.0e-7 ) - return(x); - -if( z < 0.5 ) - { - z = x * x; - s = x + x * z * (polevl(z, P, 4) / p1evl(z, Q, 5)); - return(s); - } - -return( 0.5 * log((1.0+x)/(1.0-x)) ); -} |