diff options
author | Eric Andersen <andersen@codepoet.org> | 2001-05-10 00:40:28 +0000 |
---|---|---|
committer | Eric Andersen <andersen@codepoet.org> | 2001-05-10 00:40:28 +0000 |
commit | 1077fa4d772832f77a677ce7fb7c2d513b959e3f (patch) | |
tree | 579bee13fb0b58d2800206366ec2caecbb15f3fc /libm/float/asinhf.c | |
parent | 22358dd7ce7bb49792204b698f01a6f69b9c8e08 (diff) |
uClibc now has a math library. muahahahaha!
-Erik
Diffstat (limited to 'libm/float/asinhf.c')
-rw-r--r-- | libm/float/asinhf.c | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/libm/float/asinhf.c b/libm/float/asinhf.c new file mode 100644 index 000000000..d3fbe10a7 --- /dev/null +++ b/libm/float/asinhf.c @@ -0,0 +1,88 @@ +/* asinhf.c + * + * Inverse hyperbolic sine + * + * + * + * SYNOPSIS: + * + * float x, y, asinhf(); + * + * y = asinhf( x ); + * + * + * + * DESCRIPTION: + * + * Returns inverse hyperbolic sine of argument. + * + * If |x| < 0.5, the function is approximated by a rational + * form x + x**3 P(x)/Q(x). Otherwise, + * + * asinh(x) = log( x + sqrt(1 + x*x) ). + * + * + * + * ACCURACY: + * + * Relative error: + * arithmetic domain # trials peak rms + * IEEE -3,3 100000 2.4e-7 4.1e-8 + * + */ + +/* asinh.c */ + +/* +Cephes Math Library Release 2.2: June, 1992 +Copyright 1984, 1987, 1988, 1992 by Stephen L. Moshier +Direct inquiries to 30 Frost Street, Cambridge, MA 02140 +*/ + +/* Single precision inverse hyperbolic sine + * test interval: [-0.5, +0.5] + * trials: 10000 + * peak relative error: 8.8e-8 + * rms relative error: 3.2e-8 + */ +#include <math.h> +extern float LOGE2F; + +float logf( float ); +float sqrtf( float ); + +float asinhf( float xx ) +{ +float x, z; + +if( xx < 0 ) + x = -xx; +else + x = xx; + +if( x > 1500.0 ) + { + z = logf(x) + LOGE2F; + goto done; + } +z = x * x; +if( x < 0.5 ) + { + z = + ((( 2.0122003309E-2 * z + - 4.2699340972E-2) * z + + 7.4847586088E-2) * z + - 1.6666288134E-1) * z * x + + x; + } +else + { + z = sqrtf( z + 1.0 ); + z = logf( x + z ); + } +done: +if( xx < 0 ) + z = -z; +return( z ); +} + |