org.grouplens.lenskit.util.statistics

Class MutualInformationAccumulator

java.lang.Object

org.grouplens.lenskit.util.statistics.MutualInformationAccumulator

public class MutualInformationAccumulator
extends Object

Accumulate mutual information over two discrete variables. Slightly incorrectly, this reports 0 as the entropy and mutual information of empty sets.

Constructor Summary

Constructors

Constructor and Description
MutualInformationAccumulator(int n) Construct a new accumulator with equal-sized event spaces.
MutualInformationAccumulator(int n1, int n2) Construct a new accumulator.

Method Summary

Modifier and Type	Method and Description
void	count(int v1, int v2) Count an occurrence.
int	getCount() Get the number of events.
double	getMutualInformation() Get the mutual information.
double	getV1Entropy() Get the entropy of the first variable.
double	getV2Entropy() Get the entropy of the second variable.
void	reset() Reset to start accumulating again.

Methods inherited from class java.lang.Object

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

Constructor Detail

MutualInformationAccumulator

public MutualInformationAccumulator(int n1,
                                    int n2)

Construct a new accumulator.

Parameters:

n1 - The number of discrete values of the first variable.

n2 - The number of discrete values of the second variable.

MutualInformationAccumulator

public MutualInformationAccumulator(int n)

Construct a new accumulator with equal-sized event spaces.

Parameters:

n - The number of discrete values of each variable.

Method Detail

count

public void count(int v1,
                  int v2)

Count an occurrence.

Parameters:

v1 - The value of the first variable.

v2 - The value of the second variable.

getMutualInformation

public double getMutualInformation()

Get the mutual information.

Returns:

The mutual information accumulated so far.

getV1Entropy

public double getV1Entropy()

Get the entropy of the first variable.

Returns:

The accumulated entropy of the first variable.

getV2Entropy

public double getV2Entropy()

Get the entropy of the second variable.

Returns:

The accumulated entropy of the second variable.

getCount

public int getCount()

Get the number of events.

Returns:

The number of events accumulated.

reset

public void reset()

Reset to start accumulating again.