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Diffstat (limited to 'libm/float/asinf.c')
-rw-r--r-- | libm/float/asinf.c | 186 |
1 files changed, 0 insertions, 186 deletions
diff --git a/libm/float/asinf.c b/libm/float/asinf.c deleted file mode 100644 index c96d75acb..000000000 --- a/libm/float/asinf.c +++ /dev/null @@ -1,186 +0,0 @@ -/* asinf.c - * - * Inverse circular sine - * - * - * - * SYNOPSIS: - * - * float x, y, asinf(); - * - * y = asinf( x ); - * - * - * - * DESCRIPTION: - * - * Returns radian angle between -pi/2 and +pi/2 whose sine is x. - * - * A polynomial of the form x + x**3 P(x**2) - * is used for |x| in the interval [0, 0.5]. If |x| > 0.5 it is - * transformed by the identity - * - * asin(x) = pi/2 - 2 asin( sqrt( (1-x)/2 ) ). - * - * - * ACCURACY: - * - * Relative error: - * arithmetic domain # trials peak rms - * IEEE -1, 1 100000 2.5e-7 5.0e-8 - * - * - * ERROR MESSAGES: - * - * message condition value returned - * asinf domain |x| > 1 0.0 - * - */ -/* acosf() - * - * Inverse circular cosine - * - * - * - * SYNOPSIS: - * - * float x, y, acosf(); - * - * y = acosf( x ); - * - * - * - * DESCRIPTION: - * - * Returns radian angle between -pi/2 and +pi/2 whose cosine - * is x. - * - * Analytically, acos(x) = pi/2 - asin(x). However if |x| is - * near 1, there is cancellation error in subtracting asin(x) - * from pi/2. Hence if x < -0.5, - * - * acos(x) = pi - 2.0 * asin( sqrt((1+x)/2) ); - * - * or if x > +0.5, - * - * acos(x) = 2.0 * asin( sqrt((1-x)/2) ). - * - * - * ACCURACY: - * - * Relative error: - * arithmetic domain # trials peak rms - * IEEE -1, 1 100000 1.4e-7 4.2e-8 - * - * - * ERROR MESSAGES: - * - * message condition value returned - * acosf domain |x| > 1 0.0 - */ - -/* asin.c */ - -/* -Cephes Math Library Release 2.2: June, 1992 -Copyright 1984, 1987, 1992 by Stephen L. Moshier -Direct inquiries to 30 Frost Street, Cambridge, MA 02140 -*/ - -/* Single precision circular arcsine - * test interval: [-0.5, +0.5] - * trials: 10000 - * peak relative error: 6.7e-8 - * rms relative error: 2.5e-8 - */ -#include <math.h> -extern float PIF, PIO2F; - -float sqrtf( float ); - -float asinf( float xx ) -{ -float a, x, z; -int sign, flag; - -x = xx; - -if( x > 0 ) - { - sign = 1; - a = x; - } -else - { - sign = -1; - a = -x; - } - -if( a > 1.0 ) - { - mtherr( "asinf", DOMAIN ); - return( 0.0 ); - } - -if( a < 1.0e-4 ) - { - z = a; - goto done; - } - -if( a > 0.5 ) - { - z = 0.5 * (1.0 - a); - x = sqrtf( z ); - flag = 1; - } -else - { - x = a; - z = x * x; - flag = 0; - } - -z = -(((( 4.2163199048E-2 * z - + 2.4181311049E-2) * z - + 4.5470025998E-2) * z - + 7.4953002686E-2) * z - + 1.6666752422E-1) * z * x - + x; - -if( flag != 0 ) - { - z = z + z; - z = PIO2F - z; - } -done: -if( sign < 0 ) - z = -z; -return( z ); -} - - - - -float acosf( float x ) -{ - -if( x < -1.0 ) - goto domerr; - -if( x < -0.5) - return( PIF - 2.0 * asinf( sqrtf(0.5*(1.0+x)) ) ); - -if( x > 1.0 ) - { -domerr: mtherr( "acosf", DOMAIN ); - return( 0.0 ); - } - -if( x > 0.5 ) - return( 2.0 * asinf( sqrtf(0.5*(1.0-x) ) ) ); - -return( PIO2F - asinf(x) ); -} - |