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authorEric Andersen <andersen@codepoet.org>2001-11-22 14:04:29 +0000
committerEric Andersen <andersen@codepoet.org>2001-11-22 14:04:29 +0000
commit7ce331c01ce6eb7b3f5c715a38a24359da9c6ee2 (patch)
tree3a7e8476e868ae15f4da1b7ce26b2db6f434468c /libm/float/ivf.c
parentc117dd5fb183afb1a4790a6f6110d88704be6bf8 (diff)
Totally rework the math library, this time based on the MacOs X
math library (which is itself based on the math lib from FreeBSD). -Erik
Diffstat (limited to 'libm/float/ivf.c')
-rw-r--r--libm/float/ivf.c114
1 files changed, 0 insertions, 114 deletions
diff --git a/libm/float/ivf.c b/libm/float/ivf.c
deleted file mode 100644
index b7ab2b619..000000000
--- a/libm/float/ivf.c
+++ /dev/null
@@ -1,114 +0,0 @@
-/* ivf.c
- *
- * Modified Bessel function of noninteger order
- *
- *
- *
- * SYNOPSIS:
- *
- * float v, x, y, ivf();
- *
- * y = ivf( v, x );
- *
- *
- *
- * DESCRIPTION:
- *
- * Returns modified Bessel function of order v of the
- * argument. If x is negative, v must be integer valued.
- *
- * The function is defined as Iv(x) = Jv( ix ). It is
- * here computed in terms of the confluent hypergeometric
- * function, according to the formula
- *
- * v -x
- * Iv(x) = (x/2) e hyperg( v+0.5, 2v+1, 2x ) / gamma(v+1)
- *
- * If v is a negative integer, then v is replaced by -v.
- *
- *
- * ACCURACY:
- *
- * Tested at random points (v, x), with v between 0 and
- * 30, x between 0 and 28.
- * arithmetic domain # trials peak rms
- * Relative error:
- * IEEE 0,15 3000 4.7e-6 5.4e-7
- * Absolute error (relative when function > 1)
- * IEEE 0,30 5000 8.5e-6 1.3e-6
- *
- * Accuracy is diminished if v is near a negative integer.
- * The useful domain for relative error is limited by overflow
- * of the single precision exponential function.
- *
- * See also hyperg.c.
- *
- */
- /* iv.c */
-/* Modified Bessel function of noninteger order */
-/* If x < 0, then v must be an integer. */
-
-
-/*
-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
-*/
-
-
-#include <math.h>
-
-extern float MAXNUMF;
-#define fabsf(x) ( (x) < 0 ? -(x) : (x) )
-
-float hypergf(float, float, float);
-float expf(float), gammaf(float), logf(float), floorf(float);
-
-float ivf( float v, float x )
-{
-int sign;
-float t, ax;
-
-/* If v is a negative integer, invoke symmetry */
-t = floorf(v);
-if( v < 0.0 )
- {
- if( t == v )
- {
- v = -v; /* symmetry */
- t = -t;
- }
- }
-/* If x is negative, require v to be an integer */
-sign = 1;
-if( x < 0.0 )
- {
- if( t != v )
- {
- mtherr( "ivf", DOMAIN );
- return( 0.0 );
- }
- if( v != 2.0 * floorf(v/2.0) )
- sign = -1;
- }
-
-/* Avoid logarithm singularity */
-if( x == 0.0 )
- {
- if( v == 0.0 )
- return( 1.0 );
- if( v < 0.0 )
- {
- mtherr( "ivf", OVERFLOW );
- return( MAXNUMF );
- }
- else
- return( 0.0 );
- }
-
-ax = fabsf(x);
-t = v * logf( 0.5 * ax ) - x;
-t = sign * expf(t) / gammaf( v + 1.0 );
-ax = v + 0.5;
-return( t * hypergf( ax, 2.0 * ax, 2.0 * x ) );
-}