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Diffstat (limited to 'libm/float/k1f.c')
-rw-r--r-- | libm/float/k1f.c | 174 |
1 files changed, 0 insertions, 174 deletions
diff --git a/libm/float/k1f.c b/libm/float/k1f.c deleted file mode 100644 index d5b9bdfce..000000000 --- a/libm/float/k1f.c +++ /dev/null @@ -1,174 +0,0 @@ -/* k1f.c - * - * Modified Bessel function, third kind, order one - * - * - * - * SYNOPSIS: - * - * float x, y, k1f(); - * - * y = k1f( x ); - * - * - * - * DESCRIPTION: - * - * Computes the modified Bessel function of the third kind - * of order one of the argument. - * - * The range is partitioned into the two intervals [0,2] and - * (2, infinity). Chebyshev polynomial expansions are employed - * in each interval. - * - * - * - * ACCURACY: - * - * Relative error: - * arithmetic domain # trials peak rms - * IEEE 0, 30 30000 4.6e-7 7.6e-8 - * - * ERROR MESSAGES: - * - * message condition value returned - * k1 domain x <= 0 MAXNUM - * - */ -/* k1ef.c - * - * Modified Bessel function, third kind, order one, - * exponentially scaled - * - * - * - * SYNOPSIS: - * - * float x, y, k1ef(); - * - * y = k1ef( x ); - * - * - * - * DESCRIPTION: - * - * Returns exponentially scaled modified Bessel function - * of the third kind of order one of the argument: - * - * k1e(x) = exp(x) * k1(x). - * - * - * - * ACCURACY: - * - * Relative error: - * arithmetic domain # trials peak rms - * IEEE 0, 30 30000 4.9e-7 6.7e-8 - * See k1(). - * - */ - -/* -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 -*/ - -#include <math.h> - -/* Chebyshev coefficients for x(K1(x) - log(x/2) I1(x)) - * in the interval [0,2]. - * - * lim(x->0){ x(K1(x) - log(x/2) I1(x)) } = 1. - */ - -#define MINNUMF 6.0e-39 -static float A[] = -{ --2.21338763073472585583E-8f, --2.43340614156596823496E-6f, --1.73028895751305206302E-4f, --6.97572385963986435018E-3f, --1.22611180822657148235E-1f, --3.53155960776544875667E-1f, - 1.52530022733894777053E0f -}; - - - - -/* Chebyshev coefficients for exp(x) sqrt(x) K1(x) - * in the interval [2,infinity]. - * - * lim(x->inf){ exp(x) sqrt(x) K1(x) } = sqrt(pi/2). - */ - -static float B[] = -{ - 2.01504975519703286596E-9f, --1.03457624656780970260E-8f, - 5.74108412545004946722E-8f, --3.50196060308781257119E-7f, - 2.40648494783721712015E-6f, --1.93619797416608296024E-5f, - 1.95215518471351631108E-4f, --2.85781685962277938680E-3f, - 1.03923736576817238437E-1f, - 2.72062619048444266945E0f -}; - - - -extern float MAXNUMF; -#ifdef ANSIC -float chbevlf(float, float *, int); -float expf(float), i1f(float), logf(float), sqrtf(float); -#else -float chbevlf(), expf(), i1f(), logf(), sqrtf(); -#endif - -float k1f(float xx) -{ -float x, y; - -x = xx; -if( x <= MINNUMF ) - { - mtherr( "k1f", DOMAIN ); - return( MAXNUMF ); - } - -if( x <= 2.0f ) - { - y = x * x - 2.0f; - y = logf( 0.5f * x ) * i1f(x) + chbevlf( y, A, 7 ) / x; - return( y ); - } - -return( expf(-x) * chbevlf( 8.0f/x - 2.0f, B, 10 ) / sqrtf(x) ); - -} - - - -float k1ef( float xx ) -{ -float x, y; - -x = xx; -if( x <= 0.0f ) - { - mtherr( "k1ef", DOMAIN ); - return( MAXNUMF ); - } - -if( x <= 2.0f ) - { - y = x * x - 2.0f; - y = logf( 0.5f * x ) * i1f(x) + chbevlf( y, A, 7 ) / x; - return( y * expf(x) ); - } - -return( chbevlf( 8.0f/x - 2.0f, B, 10 ) / sqrtf(x) ); - -} |