/* sinhf.c * * Hyperbolic sine * * * * SYNOPSIS: * * float x, y, sinhf(); * * y = sinhf( x ); * * * * DESCRIPTION: * * Returns hyperbolic sine of argument in the range MINLOGF to * MAXLOGF. * * The range is partitioned into two segments. If |x| <= 1, a * polynomial approximation is used. * Otherwise the calculation is sinh(x) = ( exp(x) - exp(-x) )/2. * * * * ACCURACY: * * Relative error: * arithmetic domain # trials peak rms * IEEE +-MAXLOG 100000 1.1e-7 2.9e-8 * */ /* Cephes Math Library Release 2.2: June, 1992 Copyright 1984, 1987, 1989, 1992 by Stephen L. Moshier Direct inquiries to 30 Frost Street, Cambridge, MA 02140 */ /* Single precision hyperbolic sine * test interval: [-1, +1] * trials: 10000 * peak relative error: 9.0e-8 * rms relative error: 3.0e-8 */ #include <math.h> extern float MAXLOGF, MAXNUMF; float expf( float ); float sinhf( float xx ) { register float z; float x; x = xx; if( xx < 0 ) z = -x; else z = x; if( z > MAXLOGF ) { mtherr( "sinhf", DOMAIN ); if( x > 0 ) return( MAXNUMF ); else return( -MAXNUMF ); } if( z > 1.0 ) { z = expf(z); z = 0.5*z - (0.5/z); if( x < 0 ) z = -z; } else { z = x * x; z = (( 2.03721912945E-4 * z + 8.33028376239E-3) * z + 1.66667160211E-1) * z * x + x; } return( z ); }