umontreal.iro.lecuyer.randvar
Class NegativeBinomialConvolutionGen

java.lang.Object
  umontreal.iro.lecuyer.randvar.RandomVariateGenInt
      umontreal.iro.lecuyer.randvar.NegativeBinomialGen
          umontreal.iro.lecuyer.randvar.NegativeBinomialConvolutionGen

public class NegativeBinomialConvolutionGen
extends NegativeBinomialGen

Implements negative binomial random variate generators by the convolution method. The method generates n geometric variates with probability p and adds them up.

The algorithm is slow if n is large. A local copy of the parameters n and p is maintained in this class.

Constructor Summary

NegativeBinomialConvolutionGen(RandomStream s, NegativeBinomialDist dist)
Creates a new generator for the distribution dist, using stream s.

Method Summary

int	nextInt() Generates a random number (an integer) from the discrete distribution contained in this object.
static int	nextInt(RandomStream s, int n, double p)

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

getDistribution, getStream, nextArrayOfInt

Methods inherited from class java.lang.Object

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

Constructor Detail

NegativeBinomialConvolutionGen

public NegativeBinomialConvolutionGen(RandomStream s,
                                      NegativeBinomialDist dist)

Creates a new generator for the distribution dist, using stream s.

Method Detail

nextInt

public int nextInt()

Description copied from class: RandomVariateGenInt

Generates a random number (an integer) from the discrete 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:

nextInt in class NegativeBinomialGen

Returns:

the generated value

nextInt

public static int nextInt(RandomStream s,
                          int n,
                          double p)