umontreal.iro.lecuyer.randvar

Class PoissonGen

java.lang.Object

umontreal.iro.lecuyer.randvar.RandomVariateGen

umontreal.iro.lecuyer.randvar.RandomVariateGenInt

umontreal.iro.lecuyer.randvar.PoissonGen

Direct Known Subclasses:

PoissonTIACGen

public class PoissonGen
extends RandomVariateGenInt

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

p(x) = e^-λλ^x/(x!) for x = 0, 1,...

where λ > 0 is a real valued parameter equal to the mean.

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

Constructor Summary

Constructors

Constructor and Description
PoissonGen(RandomStream s, double lambda) Creates a Poisson random variate generator with parameter λ = lambda, using stream s.
PoissonGen(RandomStream s, PoissonDist dist) Creates a new random variate generator using the Poisson distribution dist and stream s.

Method Summary

Modifier and Type	Method and Description
double	getLambda() Returns the λ associated with this object.
static int	nextInt(RandomStream s, double lambda) A static method for generating a random variate from a Poisson distribution with parameter λ = lambda.

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

PoissonGen

public PoissonGen(RandomStream s,
                  double lambda)

Creates a Poisson random variate generator with parameter λ = lambda, using stream s.

PoissonGen

public PoissonGen(RandomStream s,
                  PoissonDist dist)

Creates a new random variate generator using the Poisson distribution dist and stream s.

Method Detail

nextInt

public static int nextInt(RandomStream s,
                          double lambda)

A static method for generating a random variate from a Poisson distribution with parameter λ = lambda.

getLambda

public double getLambda()

Returns the λ associated with this object.