de.lmu.ifi.dbs.elki.distance.distancefunction.probabilistic

Class KullbackLeiblerDivergenceAsymmetricDistanceFunction

java.lang.Object

de.lmu.ifi.dbs.elki.distance.distancefunction.AbstractNumberVectorDistanceFunction

de.lmu.ifi.dbs.elki.distance.distancefunction.probabilistic.KullbackLeiblerDivergenceAsymmetricDistanceFunction

All Implemented Interfaces:

DistanceFunction<NumberVector>, NumberVectorDistanceFunction<NumberVector>, PrimitiveDistanceFunction<NumberVector>

@Reference(authors="S. Kullback",
           title="Information theory and statistics",
           booktitle="",
           bibkey="books/dover/Kullback59")
 @Alias(value="kl")
public class KullbackLeiblerDivergenceAsymmetricDistanceFunction
extends AbstractNumberVectorDistanceFunction

Kullback-Leibler divergence, also known as relative entropy, information deviation, or just KL-distance (albeit asymmetric).

\[KL(\vec{x},\vec{y}):=\sum\nolimits_i x_i\log\tfrac{x_i}{y_i}\]

For a version with the arguments reversed, see KullbackLeiblerDivergenceReverseAsymmetricDistanceFunction.

For a symmetric version, see JeffreyDivergenceDistanceFunction.

Reference:

S. Kullback
Information theory and statistics

Since:

0.6.0

Author:

Erich Schubert

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	KullbackLeiblerDivergenceAsymmetricDistanceFunction.Parameterizer Parameterization class, using the static instance.

Field Summary

Fields

Modifier and Type	Field and Description
static KullbackLeiblerDivergenceAsymmetricDistanceFunction	STATIC Static instance.

Constructor Summary

Constructors

Constructor and Description
KullbackLeiblerDivergenceAsymmetricDistanceFunction() Deprecated. Use static instance!

Method Summary

Modifier and Type	Method and Description
double	distance(NumberVector v1, NumberVector v2) Computes the distance between two given vectors according to this distance function.
boolean	equals(java.lang.Object obj)
int	hashCode()
boolean	isSymmetric() Is this function symmetric?
java.lang.String	toString()

Methods inherited from class de.lmu.ifi.dbs.elki.distance.distancefunction.AbstractNumberVectorDistanceFunction

dimensionality, dimensionality, dimensionality, dimensionality, dimensionality, dimensionality, dimensionality, dimensionality, getInputTypeRestriction

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface de.lmu.ifi.dbs.elki.distance.distancefunction.PrimitiveDistanceFunction

instantiate

Methods inherited from interface de.lmu.ifi.dbs.elki.distance.distancefunction.DistanceFunction

isMetric, isSquared

Field Detail

STATIC

public static final KullbackLeiblerDivergenceAsymmetricDistanceFunction STATIC

Static instance. Use this!

Constructor Detail

KullbackLeiblerDivergenceAsymmetricDistanceFunction

@Deprecated
public KullbackLeiblerDivergenceAsymmetricDistanceFunction()

Deprecated. Use static instance!

Constructor for the Kullback-Leibler divergence.

Method Detail

distance

public double distance(NumberVector v1,
                       NumberVector v2)

Description copied from interface: NumberVectorDistanceFunction

Computes the distance between two given vectors according to this distance function.

Parameters:

v1 - first vector

v2 - second vector

Returns:

the distance between two given vectors according to this distance function

isSymmetric

public boolean isSymmetric()

Description copied from interface: DistanceFunction

Is this function symmetric?

Returns:

true when symmetric

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object