uk.ac.liv.prng
Class DiscreteProbabilityDistribution

java.lang.Object
  uk.ac.liv.prng.DiscreteProbabilityDistribution

All Implemented Interfaces:

java.lang.Cloneable, Prototypeable, Resetable, java.io.Serializable

public class DiscreteProbabilityDistribution

extends java.lang.Object

implements Resetable, java.io.Serializable, Prototypeable

A class representing a discrete probability distribution which can used to generate random events according to the specified distribution. The output from a uniform PRNG is used to to select from the different possible events.

Version:

$Revision: 1.7 $

Author:

Steve Phelps

See Also:

Serialized Form

Nested Class Summary

class

DiscreteProbabilityDistribution.ProbabilityError

Field Summary

protected int	k The number of possible events for this distribution.
protected double[]	p The probability distribution.

Constructor Summary

DiscreteProbabilityDistribution(int k)
Construct a new distribution with k possible events.

Method Summary

int	computeMax() Compute the maximum value of the random variable defined by this distribution.
double	computeMean() Compute the expected value of the random variable defined by this distribution.
int	computeMin() Compute the minimum value of the random variable defined by this distribution.
void	computeStats(CummulativeDistribution stats)
int	generateRandomEvent() Generate a random event according to the probability distribution.
double	getProbability(int i) Get the probability of the ith event.
java.lang.Object	protoClone()
void	reset() Reinitialise our state to the original settings.
void	setProbability(int i, double probability) Set the probability of the ith event.
java.lang.String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

p

protected double[] p

The probability distribution.

k

protected int k

The number of possible events for this distribution.

Constructor Detail

DiscreteProbabilityDistribution

public DiscreteProbabilityDistribution(int k)

Construct a new distribution with k possible events.

Parameters:

k - The number of possible events for this random variable

Method Detail

protoClone

public java.lang.Object protoClone()

Specified by:

protoClone in interface Prototypeable

setProbability

public void setProbability(int i,
                           double probability)

Set the probability of the ith event.

Parameters:

i - The event

probability - The probability of event i occuring

getProbability

public double getProbability(int i)

Get the probability of the ith event.

Parameters:

i - The event

generateRandomEvent

public int generateRandomEvent()

Generate a random event according to the probability distribution.

Returns:

An integer value representing one of the possible events.

reset

public void reset()

Description copied from interface: Resetable

Reinitialise our state to the original settings.

Specified by:

reset in interface Resetable

computeMean

public double computeMean()

Compute the expected value of the random variable defined by this distribution.

Returns:

The expected value of the distribution

computeMin

public int computeMin()

Compute the minimum value of the random variable defined by this distribution.

Returns:

The minimum integer value

computeMax

public int computeMax()

Compute the maximum value of the random variable defined by this distribution.

Returns:

The maximum integer value

computeStats

public void computeStats(CummulativeDistribution stats)

toString

public java.lang.String toString()