diff options
author | Eric Andersen <andersen@codepoet.org> | 2001-05-10 00:40:28 +0000 |
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committer | Eric Andersen <andersen@codepoet.org> | 2001-05-10 00:40:28 +0000 |
commit | 1077fa4d772832f77a677ce7fb7c2d513b959e3f (patch) | |
tree | 579bee13fb0b58d2800206366ec2caecbb15f3fc /libm/ldouble/atanhl.c | |
parent | 22358dd7ce7bb49792204b698f01a6f69b9c8e08 (diff) |
uClibc now has a math library. muahahahaha!
-Erik
Diffstat (limited to 'libm/ldouble/atanhl.c')
-rw-r--r-- | libm/ldouble/atanhl.c | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/libm/ldouble/atanhl.c b/libm/ldouble/atanhl.c new file mode 100644 index 000000000..3dc7bd2eb --- /dev/null +++ b/libm/ldouble/atanhl.c @@ -0,0 +1,163 @@ +/* atanhl.c + * + * Inverse hyperbolic tangent, long double precision + * + * + * + * SYNOPSIS: + * + * long double x, y, atanhl(); + * + * y = atanhl( x ); + * + * + * + * DESCRIPTION: + * + * Returns inverse hyperbolic tangent of argument in the range + * MINLOGL to MAXLOGL. + * + * 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 + * IEEE -1,1 30000 1.1e-19 3.3e-20 + * + */ + + + +/* +Cephes Math Library Release 2.7: May, 1998 +Copyright (C) 1987, 1991, 1998 by Stephen L. Moshier +*/ + +#include <math.h> + +#ifdef UNK +static long double P[] = { + 2.9647757819596835680719E-3L, +-8.0026596513099094380633E-1L, + 7.7920941408493040219831E0L, +-2.4330686602187898836837E1L, + 3.0204265014595622991082E1L, +-1.2961142942114056581210E1L, +}; +static long double Q[] = { +/* 1.0000000000000000000000E0L,*/ +-1.3729634163247557081869E1L, + 6.2320841104088512332185E1L, +-1.2469344457045341444078E2L, + 1.1394285233959210574352E2L, +-3.8883428826342169425890E1L, +}; +#endif + +#ifdef IBMPC +static short P[] = { +0x3aa2,0x036b,0xaf06,0xc24c,0x3ff6, XPD +0x528e,0x56e8,0x3af4,0xccde,0xbffe, XPD +0x9d89,0xc9a1,0xd5cf,0xf958,0x4001, XPD +0xa653,0x6cfa,0x3f04,0xc2a5,0xc003, XPD +0xc651,0x2b3d,0x55b2,0xf1a2,0x4003, XPD +0xd76d,0xf293,0xd76b,0xcf60,0xc002, XPD +}; +static short Q[] = { +/*0x0000,0x0000,0x0000,0x8000,0x3fff,*/ +0xd1b9,0x5314,0x94df,0xdbac,0xc002, XPD +0x3caa,0x0517,0x8a92,0xf948,0x4004, XPD +0x535e,0xaf5f,0x0b2a,0xf963,0xc005, XPD +0xa6f9,0xb702,0xbd8a,0xe3e2,0x4005, XPD +0xe136,0xf5ee,0xa190,0x9b88,0xc004, XPD +}; +#endif + +#ifdef MIEEE +static long P[] = { +0x3ff60000,0xc24caf06,0x036b3aa2, +0xbffe0000,0xccde3af4,0x56e8528e, +0x40010000,0xf958d5cf,0xc9a19d89, +0xc0030000,0xc2a53f04,0x6cfaa653, +0x40030000,0xf1a255b2,0x2b3dc651, +0xc0020000,0xcf60d76b,0xf293d76d, +}; +static long Q[] = { +/*0x3fff0000,0x80000000,0x00000000,*/ +0xc0020000,0xdbac94df,0x5314d1b9, +0x40040000,0xf9488a92,0x05173caa, +0xc0050000,0xf9630b2a,0xaf5f535e, +0x40050000,0xe3e2bd8a,0xb702a6f9, +0xc0040000,0x9b88a190,0xf5eee136, +}; +#endif + +extern long double MAXNUML; +#ifdef ANSIPROT +extern long double fabsl ( long double ); +extern long double logl ( long double ); +extern long double polevll ( long double, void *, int ); +extern long double p1evll ( long double, void *, int ); +#else +long double fabsl(), logl(), polevll(), p1evll(); +#endif +#ifdef INFINITIES +extern long double INFINITYL; +#endif +#ifdef NANS +extern long double NANL; +#endif + +long double atanhl(x) +long double x; +{ +long double s, z; + +#ifdef MINUSZERO +if( x == 0.0L ) + return(x); +#endif +z = fabsl(x); +if( z >= 1.0L ) + { + if( x == 1.0L ) + { +#ifdef INFINITIES + return( INFINITYL ); +#else + return( MAXNUML ); +#endif + } + if( x == -1.0L ) + { +#ifdef INFINITIES + return( -INFINITYL ); +#else + return( -MAXNUML ); +#endif + } + mtherr( "atanhl", DOMAIN ); +#ifdef NANS + return( NANL ); +#else + return( MAXNUML ); +#endif + } + +if( z < 1.0e-8L ) + return(x); + +if( z < 0.5L ) + { + z = x * x; + s = x + x * z * (polevll(z, P, 5) / p1evll(z, Q, 5)); + return(s); + } + +return( 0.5L * logl((1.0L+x)/(1.0L-x)) ); +} |