broadwick.statistics.distributions

Class MultinomialDistribution

java.lang.Object

broadwick.statistics.distributions.MultinomialDistribution

All Implemented Interfaces:

Serializable

public class MultinomialDistribution
extends Object
implements Serializable

Defines the Multinomial distribution with parameters numSamples and probabilities₁, ...,probabilities_d. The probability mass function is

P[X = (x₁,..., x_d)] = numSamples!∏_i=1^dprobabilities_i^x_i/(∏_i=1^dx_i!),

where ∑_i=1^dx_i = numSamples and ∑_i=1^dprobabilities_i = 1.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
private int	dimension
private int	numSamples
private double[]	probabilities

Constructor Summary

Constructors

Constructor and Description
MultinomialDistribution(int n, double[] p) Creates a MultinomialDist object with parameters numSamples and (probabilities1,...,probabilitiesd) such that ∑i=1dprobabilitiesi = 1.

Method Summary

Modifier and Type	Method and Description
int	getN() Returns the parameter N of this object.
double[]	getP() Returns the parameters (probabilities1,...,probabilitiesd) of this object.
double	prob(int[] x) Returns the probability mass function p(x1, x2,…, xd), which should be a real number in [0, 1].
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

numSamples

private int numSamples

probabilities

private double[] probabilities

dimension

private int dimension

Constructor Detail

MultinomialDistribution

public MultinomialDistribution(int n,
                               double[] p)

Creates a MultinomialDist object with parameters numSamples and (probabilities₁,...,probabilities_d) such that ∑_i=1^dprobabilities_i = 1. We have probabilities_i = probabilities[i-1].

Parameters:

n - the number of samples.

p - the array of probabilities

Method Detail

getN

public final int getN()

Returns the parameter N of this object.

Returns:

the total number of samples.

getP

public final double[] getP()

Returns the parameters (probabilities₁,...,probabilities_d) of this object.

Returns:

the array of probabilities.

prob

public final double prob(int[] x)

Returns the probability mass function p(x₁, x₂,…, x_d), which should be a real number in [0, 1].

Parameters:

x - value at which the mass function must be evaluated

Returns:

the mass function evaluated at x

toString

public final String toString()

Overrides:

toString in class Object