pal.math

## Class GammaFunction

• public class GammaFunction
extends Object
gamma function
Version:
\$Id: GammaFunction.java,v 1.1 2006/06/01 15:27:32 gene099 Exp \$
Author:
Korbinian Strimmer
• ### Constructor Summary

Constructors
Constructor and Description
GammaFunction()
• ### Method Summary

All Methods
Modifier and Type Method and Description
static double incompleteGammaP(double a, double x)
Incomplete Gamma function P(a,x) = 1-Q(a,x) (a cleanroom implementation of Numerical Recipes gammp(a,x); in Mathematica this function is 1-GammaRegularized)
static double incompleteGammaP(double a, double x, double lnGammaA)
Incomplete Gamma function P(a,x) = 1-Q(a,x) (a cleanroom implementation of Numerical Recipes gammp(a,x); in Mathematica this function is 1-GammaRegularized)
static double incompleteGammaQ(double a, double x)
Incomplete Gamma function Q(a,x) (a cleanroom implementation of Numerical Recipes gammq(a,x); in Mathematica this function is called GammaRegularized)
static double lnGamma(double alpha)
log Gamma function: ln(gamma(alpha)) for alpha>0, accurate to 10 decimal places
• ### Constructor Detail

• #### GammaFunction

public GammaFunction()
• ### Method Detail

• #### lnGamma

public static double lnGamma(double alpha)
log Gamma function: ln(gamma(alpha)) for alpha>0, accurate to 10 decimal places
Parameters:
alpha - argument
• #### incompleteGammaQ

public static double incompleteGammaQ(double a,
double x)
Incomplete Gamma function Q(a,x) (a cleanroom implementation of Numerical Recipes gammq(a,x); in Mathematica this function is called GammaRegularized)
Parameters:
a - parameter
x - argument
Returns:
function value
• #### incompleteGammaP

public static double incompleteGammaP(double a,
double x)
Incomplete Gamma function P(a,x) = 1-Q(a,x) (a cleanroom implementation of Numerical Recipes gammp(a,x); in Mathematica this function is 1-GammaRegularized)
Parameters:
a - parameter
x - argument
Returns:
function value
• #### incompleteGammaP

public static double incompleteGammaP(double a,
double x,
double lnGammaA)
Incomplete Gamma function P(a,x) = 1-Q(a,x) (a cleanroom implementation of Numerical Recipes gammp(a,x); in Mathematica this function is 1-GammaRegularized)
Parameters:
a - parameter
x - argument
lnGammaA - precomputed lnGamma(a)
Returns:
function value