diff options
author | Eric Andersen <andersen@codepoet.org> | 2001-05-10 00:40:28 +0000 |
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committer | Eric Andersen <andersen@codepoet.org> | 2001-05-10 00:40:28 +0000 |
commit | 1077fa4d772832f77a677ce7fb7c2d513b959e3f (patch) | |
tree | 579bee13fb0b58d2800206366ec2caecbb15f3fc /libm/ldouble/nbdtrl.c | |
parent | 22358dd7ce7bb49792204b698f01a6f69b9c8e08 (diff) |
uClibc now has a math library. muahahahaha!
-Erik
Diffstat (limited to 'libm/ldouble/nbdtrl.c')
-rw-r--r-- | libm/ldouble/nbdtrl.c | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/libm/ldouble/nbdtrl.c b/libm/ldouble/nbdtrl.c new file mode 100644 index 000000000..91593f544 --- /dev/null +++ b/libm/ldouble/nbdtrl.c @@ -0,0 +1,197 @@ +/* nbdtrl.c + * + * Negative binomial distribution + * + * + * + * SYNOPSIS: + * + * int k, n; + * long double p, y, nbdtrl(); + * + * y = nbdtrl( k, n, p ); + * + * + * + * DESCRIPTION: + * + * Returns the sum of the terms 0 through k of the negative + * binomial distribution: + * + * k + * -- ( n+j-1 ) n j + * > ( ) p (1-p) + * -- ( j ) + * j=0 + * + * In a sequence of Bernoulli trials, this is the probability + * that k or fewer failures precede the nth success. + * + * The terms are not computed individually; instead the incomplete + * beta integral is employed, according to the formula + * + * y = nbdtr( k, n, p ) = incbet( n, k+1, p ). + * + * The arguments must be positive, with p ranging from 0 to 1. + * + * + * + * ACCURACY: + * + * Tested at random points (k,n,p) with k and n between 1 and 10,000 + * and p between 0 and 1. + * + * arithmetic domain # trials peak rms + * Absolute error: + * IEEE 0,10000 10000 9.8e-15 2.1e-16 + * + */ +/* nbdtrcl.c + * + * Complemented negative binomial distribution + * + * + * + * SYNOPSIS: + * + * int k, n; + * long double p, y, nbdtrcl(); + * + * y = nbdtrcl( k, n, p ); + * + * + * + * DESCRIPTION: + * + * Returns the sum of the terms k+1 to infinity of the negative + * binomial distribution: + * + * inf + * -- ( n+j-1 ) n j + * > ( ) p (1-p) + * -- ( j ) + * j=k+1 + * + * The terms are not computed individually; instead the incomplete + * beta integral is employed, according to the formula + * + * y = nbdtrc( k, n, p ) = incbet( k+1, n, 1-p ). + * + * The arguments must be positive, with p ranging from 0 to 1. + * + * + * + * ACCURACY: + * + * See incbetl.c. + * + */ +/* nbdtril + * + * Functional inverse of negative binomial distribution + * + * + * + * SYNOPSIS: + * + * int k, n; + * long double p, y, nbdtril(); + * + * p = nbdtril( k, n, y ); + * + * + * + * DESCRIPTION: + * + * Finds the argument p such that nbdtr(k,n,p) is equal to y. + * + * ACCURACY: + * + * Tested at random points (a,b,y), with y between 0 and 1. + * + * a,b Relative error: + * arithmetic domain # trials peak rms + * IEEE 0,100 + * See also incbil.c. + */ + +/* +Cephes Math Library Release 2.3: January,1995 +Copyright 1984, 1995 by Stephen L. Moshier +*/ + +#include <math.h> +#ifdef ANSIPROT +extern long double incbetl ( long double, long double, long double ); +extern long double powl ( long double, long double ); +extern long double incbil ( long double, long double, long double ); +#else +long double incbetl(), powl(), incbil(); +#endif + +long double nbdtrcl( k, n, p ) +int k, n; +long double p; +{ +long double dk, dn; + +if( (p < 0.0L) || (p > 1.0L) ) + goto domerr; +if( k < 0 ) + { +domerr: + mtherr( "nbdtrl", DOMAIN ); + return( 0.0L ); + } +dn = n; +if( k == 0 ) + return( 1.0L - powl( p, dn ) ); + +dk = k+1; +return( incbetl( dk, dn, 1.0L - p ) ); +} + + + +long double nbdtrl( k, n, p ) +int k, n; +long double p; +{ +long double dk, dn; + +if( (p < 0.0L) || (p > 1.0L) ) + goto domerr; +if( k < 0 ) + { +domerr: + mtherr( "nbdtrl", DOMAIN ); + return( 0.0L ); + } +dn = n; +if( k == 0 ) + return( powl( p, dn ) ); + +dk = k+1; +return( incbetl( dn, dk, p ) ); +} + + +long double nbdtril( k, n, p ) +int k, n; +long double p; +{ +long double dk, dn, w; + +if( (p < 0.0L) || (p > 1.0L) ) + goto domerr; +if( k < 0 ) + { +domerr: + mtherr( "nbdtrl", DOMAIN ); + return( 0.0L ); + } +dk = k+1; +dn = n; +w = incbil( dn, dk, p ); +return( w ); +} |