SSJ
V. 2.6.

umontreal.iro.lecuyer.randvar
Class NegativeBinomialGen

java.lang.Object
  extended by umontreal.iro.lecuyer.randvar.RandomVariateGen
      extended by umontreal.iro.lecuyer.randvar.RandomVariateGenInt
          extended by umontreal.iro.lecuyer.randvar.NegativeBinomialGen

public class NegativeBinomialGen
extends RandomVariateGenInt

This class implements random variate generators having the negative binomial distribution. Its mass function is

p(x) = Γ(γ + x)/(xΓ(γ)) pγ(1 - p)x,        for x = 0, 1, 2,…

where Γ is the gamma function, γ > 0 and 0 <= p <= 1. No local copy of the parameters γ and p is maintained in this class. The (non-static) nextInt method simply calls inverseF on the distribution.


Constructor Summary
NegativeBinomialGen(RandomStream s, double gamma, double p)
          Creates a negative binomial random variate generator with parameters γ = gamma and p, using stream s.
NegativeBinomialGen(RandomStream s, NegativeBinomialDist dist)
          Creates a new generator for the distribution dist, using stream s.
 
Method Summary
 double getGamma()
          Returns the parameter γ of this object.
 double getP()
          Returns the parameter p of this object.
static int nextInt(RandomStream s, double gamma, double p)
          Generates a new variate from the negative binomial distribution, with parameters γ = gamma and p = p, using stream s.
 
Methods inherited from class umontreal.iro.lecuyer.randvar.RandomVariateGenInt
getDistribution, nextArrayOfInt, nextInt
 
Methods inherited from class umontreal.iro.lecuyer.randvar.RandomVariateGen
getStream, nextArrayOfDouble, nextDouble, setStream, toString
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

NegativeBinomialGen

public NegativeBinomialGen(RandomStream s,
                           double gamma,
                           double p)
Creates a negative binomial random variate generator with parameters γ = gamma and p, using stream s.


NegativeBinomialGen

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

Method Detail

nextInt

public static int nextInt(RandomStream s,
                          double gamma,
                          double p)
Generates a new variate from the negative binomial distribution, with parameters γ = gamma and p = p, using stream s.


getGamma

public double getGamma()
Returns the parameter γ of this object.


getP

public double getP()
Returns the parameter p of this object.


SSJ
V. 2.6.

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