SSJ
V. 1.2.5.

umontreal.iro.lecuyer.randvar
Class ChiGen

java.lang.Object
  extended by umontreal.iro.lecuyer.randvar.RandomVariateGen
      extended by umontreal.iro.lecuyer.randvar.ChiGen
Direct Known Subclasses:
ChiRatioOfUniformsGen

public class ChiGen
extends RandomVariateGen

This class implements random variate generators for the chi distribution. It has ν > 0 degrees of freedom and its density function is

f (x) = e-x2/2xν-1/(2(ν/2)-1Γ(ν/2))        for x > 0

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

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


Constructor Summary
ChiGen(RandomStream s, ChiDist dist)
          Create a new generator for the distribution dist, using stream s.
 
Method Summary
 double nextDouble()
          Generates a random number from the continuous distribution contained in this object.
static double nextDouble(RandomStream s, int nu)
          Generates a random variate from the chi distribution with ν = nu 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

ChiGen

public ChiGen(RandomStream s,
              ChiDist dist)
Create a new generator for the distribution dist, using 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 nu)
Generates a random variate from the chi distribution with ν = nu 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.