com.mapr.stats.random

Class BetaBinomialDistribution

java.lang.Object

org.apache.mahout.math.jet.random.AbstractDistribution

org.apache.mahout.math.jet.random.AbstractContinousDistribution

com.mapr.stats.random.AbstractBayesianDistribution

com.mapr.stats.random.BetaBinomialDistribution

All Implemented Interfaces:

org.apache.mahout.math.function.DoubleFunction, org.apache.mahout.math.function.IntFunction

public class BetaBinomialDistribution
extends AbstractBayesianDistribution

Implements a beta-binomial pair of conjugate distributions.

In this model, samples are distributed according to \[ \pi \sim \mathrm {Beta}(\alpha, \beta) \\ x \sim \mathrm {Bernoulli} (\pi) \] The nextDouble() method returns a sample of \(x\) and the nextMean() returns a sample of \(\pi\).

Constructor Summary

Constructors

Constructor and Description
BetaBinomialDistribution(double alpha, double beta, Random gen)

Method Summary

Methods

Modifier and Type	Method and Description
void	add(double x)
double	getMean()
double	getSamples()
double	nextDouble() Samples from a binomial whose underlying probability is distributed according to a beta distribution.
double	nextMean()
org.apache.mahout.math.jet.random.AbstractContinousDistribution	posteriorDistribution()

Methods inherited from class org.apache.mahout.math.jet.random.AbstractContinousDistribution

cdf, nextInt, pdf

Methods inherited from class org.apache.mahout.math.jet.random.AbstractDistribution

apply, apply, getRandomGenerator, randomDouble, setRandomGenerator

Methods inherited from class java.lang.Object

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

Constructor Detail

BetaBinomialDistribution

public BetaBinomialDistribution(double alpha,
                        double beta,
                        Random gen)

Method Detail

nextDouble

public double nextDouble()

Samples from a binomial whose underlying probability is distributed according to a beta distribution.

Specified by:

nextDouble in class AbstractBayesianDistribution

Returns:

A sample.

add

public void add(double x)

Specified by:

add in class AbstractBayesianDistribution

nextMean

public double nextMean()

Specified by:

nextMean in class AbstractBayesianDistribution

posteriorDistribution

public org.apache.mahout.math.jet.random.AbstractContinousDistribution posteriorDistribution()

Specified by:

posteriorDistribution in class AbstractBayesianDistribution

getMean

public double getMean()

Specified by:

getMean in class AbstractBayesianDistribution

getSamples

public double getSamples()

Specified by:

getSamples in class AbstractBayesianDistribution