Gamma (Colt 1.2.0 - API Specification)

Overview

Package

Class

Use

Tree

Deprecated

Index

Help

Colt 1.2.0

PREV CLASS NEXT CLASS

FRAMES NO FRAMES

SUMMARY: NESTED | FIELD | CONSTR | METHOD

DETAIL: FIELD | CONSTR | METHOD

cern.jet.stat
Class Gamma

java.lang.Object
  cern.jet.math.Constants
      cern.jet.stat.Gamma

public class Gamma
extends Constants

Gamma and Beta functions.

Implementation:

Some code taken and adapted from the Java 2D Graph Package 2.4, which in turn is a port from the Cephes 2.2 Math Library (C). Most Cephes code (missing from the 2D Graph Package) directly ported.

Version:: 0.9, 22-Jun-99

Method Summary
`static double`	`beta(double a, double b)` Returns the beta function of the arguments.
`static double`	`gamma(double x)` Returns the Gamma function of the argument.
`static double`	`incompleteBeta(double aa, double bb, double xx)` Returns the Incomplete Beta Function evaluated from zero to `xx`; formerly named `ibeta`.
`static double`	`incompleteGamma(double a, double x)` Returns the Incomplete Gamma function; formerly named `igamma`.
`static double`	`incompleteGammaComplement(double a, double x)` Returns the Complemented Incomplete Gamma function; formerly named `igamc`.
`static double`	`logGamma(double x)` Returns the natural logarithm of the gamma function; formerly named `lgamma`.

Methods inherited from class java.lang.Object

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

Method Detail

beta

public static double beta(double a,
                          double b)
                   throws ArithmeticException

Returns the beta function of the arguments.

                   -     -
                  | (a) | (b)
 beta( a, b )  =  -----------.
                     -
                    | (a+b)

Throws:: ArithmeticException

gamma

public static double gamma(double x)
                    throws ArithmeticException

Returns the Gamma function of the argument.

Throws:: ArithmeticException

incompleteBeta

public static double incompleteBeta(double aa,
                                    double bb,
                                    double xx)
                             throws ArithmeticException

Returns the Incomplete Beta Function evaluated from zero to xx; formerly named ibeta.

Parameters:: aa - the alpha parameter of the beta distribution.; bb - the beta parameter of the beta distribution.; xx - the integration end point.
Throws:: ArithmeticException

incompleteGamma

public static double incompleteGamma(double a,
                                     double x)
                              throws ArithmeticException

Returns the Incomplete Gamma function; formerly named igamma.

Parameters:: a - the parameter of the gamma distribution.; x - the integration end point.
Throws:: ArithmeticException

incompleteGammaComplement

public static double incompleteGammaComplement(double a,
                                               double x)
                                        throws ArithmeticException

Returns the Complemented Incomplete Gamma function; formerly named igamc.

Parameters:: a - the parameter of the gamma distribution.; x - the integration start point.
Throws:: ArithmeticException

logGamma

public static double logGamma(double x)
                       throws ArithmeticException

Returns the natural logarithm of the gamma function; formerly named lgamma.

Throws:: ArithmeticException