SSJ
V. 1.2.5.

umontreal.iro.lecuyer.randvar
Class ChiSquareGen

java.lang.Object
  extended by umontreal.iro.lecuyer.randvar.RandomVariateGen
      extended by 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) = xn/2-1e-x/2/(2n/2Γ(n/2)) for x > 0, 0 elsewhere

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

No local copy of the parameter n is maintained in this class. The (non-static) nextDouble method simply calls inverseF on the distribution.


Constructor Summary
ChiSquareGen(RandomStream s, ChiSquareDist dist)
          Create a new generator for the distribution dist and stream s.
 
Method Summary
 double nextDouble()
          Generates a random number from the continuous distribution contained in 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, setStream
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

ChiSquareGen

public ChiSquareGen(RandomStream s,
                    ChiSquareDist dist)
Create a new generator for the distribution dist and stream s.

Method Detail

nextDouble

public double nextDouble()
Description copied from class: RandomVariateGen
Generates a random number from the continuous distribution contained in this object. By default, this method uses inversion by calling the inverseF method of the distribution object. Alternative generating methods are provided in subclasses.

Overrides:
nextDouble in class RandomVariateGen
Returns:
the generated value

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.


SSJ
V. 1.2.5.

To submit a bug or ask questions, send an e-mail to Pierre L'Ecuyer.