umontreal.iro.lecuyer.randvar

Class RandomVariateGenInt

java.lang.Object

umontreal.iro.lecuyer.randvar.RandomVariateGen

umontreal.iro.lecuyer.randvar.RandomVariateGenInt

Direct Known Subclasses:

BinomialGen, GeometricGen, HypergeometricGen, LogarithmicGen, NegativeBinomialGen, PascalGen, PoissonGen, UniformIntGen, UnuranDiscreteInt

public class RandomVariateGenInt
extends RandomVariateGen

This is the base class for all generators of discrete random variates over the set of integers. Similar to RandomVariateGen, except that the generators produce integers, via the nextInt method, instead of real numbers.

Constructor Summary

Constructors

Constructor and Description
RandomVariateGenInt(RandomStream s, DiscreteDistributionInt dist) Creates a new random variate generator for the discrete distribution dist, using stream s.

Method Summary

Methods

Modifier and Type	Method and Description
DiscreteDistributionInt	getDistribution() Returns the DiscreteDistributionInt used by this generator.
void	nextArrayOfInt(int[] v, int start, int n) Generates n random numbers from the discrete distribution contained in this object.
int	nextInt() Generates a random number (an integer) from the discrete distribution contained in this object.

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

getStream, nextArrayOfDouble, nextDouble, setStream

Methods inherited from class java.lang.Object

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

Constructor Detail

RandomVariateGenInt

public RandomVariateGenInt(RandomStream s,
                   DiscreteDistributionInt dist)

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

Parameters:

s - random stream used for generating uniforms

dist - discrete distribution object of the generated values

Method Detail

nextInt

public int nextInt()

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.

Returns:

the generated value

nextArrayOfInt

public void nextArrayOfInt(int[] v,
                  int start,
                  int n)

Generates n random numbers from the discrete distribution contained in this object. The results are stored into the array v, starting from index start. By default, this method calls nextInt() n times, but one can reimplement it in subclasses for better efficiency.

Parameters:

v - array into which the variates will be stored

start - starting index, in v, of the new variates

n - number of variates being generated

getDistribution

public DiscreteDistributionInt getDistribution()

Returns the DiscreteDistributionInt used by this generator.

Overrides:

getDistribution in class RandomVariateGen

Returns:

the distribution associated to that object