vec_math
Class Gamma

java.lang.Object
  vec_math.Gamma

public class Gamma
extends Object

Class containing statically versions of the gamma and incomplete gamma function. Lit: Num.Rec. p206ff.

Nested Class Summary

static class	Gamma.Erf Error function.
static class	Gamma.InverseErf Inverse of error function: determine the argument, where erf(x) = the given vaule.

Field Summary

protected static double	EPS
protected static double	FPMIN
static double[]	GAMCOEF
protected static int	ITERMAX
static double	SER
static double	STP

Constructor Summary

Gamma()

Method Summary

static double	betai(double a, double b, double x)
private static double	contFrac(double a, double b, double x)
static double	erf(double x)
static double	erfc(double x)
protected static double	gammcf(double a, double x) Does not check right range on a,x; returns 1-P(a,x)
static double	gammln(double x) Calculates the ln of Gamma(x) if x>0.
static double	gammp(double a, double x)
static double	gammq(double a, double x) Returns the incomplete gamma functon 1-P(a,x).
protected static double	gamser(double a, double x) Does not check for right range in a,x; returns P(a,x)
static void	main(String[] arg)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

GAMCOEF

public static final double[] GAMCOEF

STP

public static final double STP

See Also:

Constant Field Values

SER

public static final double SER

See Also:

Constant Field Values

ITERMAX

protected static final int ITERMAX

See Also:

Constant Field Values

EPS

protected static final double EPS

See Also:

Constant Field Values

FPMIN

protected static final double FPMIN

See Also:

Constant Field Values

Constructor Detail

Gamma

public Gamma()

Method Detail

gammln

public static double gammln(double x)

Calculates the ln of Gamma(x) if x>0.

Parameters:

x -

Returns:

double

gammq

public static double gammq(double a,
                           double x)

Returns the incomplete gamma functon 1-P(a,x).

Parameters:

a -

x -

Returns:

double

gammp

public static double gammp(double a,
                           double x)

erf

public static double erf(double x)

erfc

public static double erfc(double x)

betai

public static double betai(double a,
                           double b,
                           double x)

contFrac

private static final double contFrac(double a,
                                     double b,
                                     double x)

gamser

protected static double gamser(double a,
                               double x)

Does not check for right range in a,x; returns P(a,x)

Parameters:

a -

x -

Returns:

double

gammcf

protected static double gammcf(double a,
                               double x)

Does not check right range on a,x; returns 1-P(a,x)

Parameters:

a -

x -

Returns:

double

main

public static void main(String[] arg)

Parameters:

arg -