umontreal.iro.lecuyer.randvar

Class ChiSquareGen

java.lang.Object

umontreal.iro.lecuyer.randvar.RandomVariateGen

umontreal.iro.lecuyer.randvar.ChiSquareGen

public class ChiSquareGen
extends RandomVariateGen

This class implements random variate generators with the chi square distribution with n > 0 degrees of freedom. Its density function is

f (x) = x^n/2-1e^-x/2/(2^n/2Γ(n/2)) for x > 0, 0 elsewhere

where Γ(x) is the gamma function defined in GammaGen.

The (non-static) nextDouble method simply calls inverseF on the distribution.

Constructor Summary

Constructors

Constructor and Description
ChiSquareGen(RandomStream s, ChiSquareDist dist) Create a new generator for the distribution dist and stream s.
ChiSquareGen(RandomStream s, int n) Creates a chi square random variate generator with n degrees of freedom, using stream s.

Method Summary

Modifier and Type	Method and Description
int	getN() Returns the value of n for this object.
static double	nextDouble(RandomStream s, int n) Generates a new variate from the chi square distribution with n degrees of freedom, using stream s.

Methods inherited from class umontreal.iro.lecuyer.randvar.RandomVariateGen

getDistribution, getStream, nextArrayOfDouble, nextDouble, setStream, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

ChiSquareGen

public ChiSquareGen(RandomStream s,
                    int n)

Creates a chi square random variate generator with n degrees of freedom, using stream s.

ChiSquareGen

public ChiSquareGen(RandomStream s,
                    ChiSquareDist dist)

Create a new generator for the distribution dist and stream s.

Method Detail

nextDouble

public static double nextDouble(RandomStream s,
                                int n)

Generates a new variate from the chi square distribution with n degrees of freedom, using stream s.

getN

public int getN()

Returns the value of n for this object.