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

Class ChiSquaredDistanceFunction

java.lang.Object

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

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

All Implemented Interfaces:

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

Direct Known Subclasses:

ChiDistanceFunction

@Alias(value="chisq")
 @Priority(value=100)
 @Reference(authors="J. Puzicha, J. M. Buhmann, Y. Rubner, C. Tomasi",
           title="Empirical evaluation of dissimilarity measures for color and texture",
           booktitle="Proc. 7th IEEE International Conference on Computer Vision",
           url="https://doi.org/10.1109/ICCV.1999.790412",
           bibkey="DBLP:conf/iccv/PuzichaRTB99")
public class ChiSquaredDistanceFunction
extends AbstractNumberVectorDistanceFunction
implements SpatialPrimitiveDistanceFunction<NumberVector>

χ² distance function, symmetric version.

This implementation assumes \(\sum_i x_i=\sum_i y_i\), and is defined as: \[\chi^2(\vec{x},\vec{y}):=2\sum\nolimits_i \tfrac{(x_i-x_i)^2}{x_i+y_i}\]

Reference:

J. Puzicha, J. M. Buhmann, Y. Rubner, C. Tomasi
Empirical evaluation of dissimilarity measures for color and texture
Proc. 7th IEEE International Conference on Computer Vision

Since:

0.6.0

Author:

Erich Schubert

Nested Class Summary

Nested Classes

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

Field Summary

Fields

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

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method and Description
double	distance(NumberVector v1, NumberVector v2) Computes the distance between two given DatabaseObjects according to this distance function.
boolean	equals(java.lang.Object obj)
SimpleTypeInformation<? super NumberVector>	getInputTypeRestriction() Get the input data type of the function.
int	hashCode()
boolean	isSquared() Squared distances, that would become metric after square root.
double	minDist(SpatialComparable mbr1, SpatialComparable mbr2) Computes the distance between the two given MBRs according to this distance function.
java.lang.String	toString()

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

dimensionality, dimensionality, dimensionality, dimensionality, dimensionality, dimensionality, dimensionality, dimensionality

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.SpatialPrimitiveDistanceFunction

instantiate

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

isMetric, isSymmetric

Field Detail

STATIC

public static final ChiSquaredDistanceFunction STATIC

Static instance. Use this!

Constructor Detail

ChiSquaredDistanceFunction

@Deprecated
public ChiSquaredDistanceFunction()

Deprecated. Use static instance!

Constructor for the Chi-Squared distance function.

Method Detail

distance

public double distance(NumberVector v1,
                       NumberVector v2)

Description copied from interface: PrimitiveDistanceFunction

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

Specified by:

distance in interface NumberVectorDistanceFunction<NumberVector>

Specified by:

distance in interface PrimitiveDistanceFunction<NumberVector>

Parameters:

v1 - first DatabaseObject

v2 - second DatabaseObject

Returns:

the distance between two given DatabaseObjects according to this distance function

minDist

public double minDist(SpatialComparable mbr1,
                      SpatialComparable mbr2)

Description copied from interface: SpatialPrimitiveDistanceFunction

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

Specified by:

minDist in interface SpatialPrimitiveDistanceFunction<NumberVector>

Parameters:

mbr1 - the first MBR object

mbr2 - the second MBR object

Returns:

the distance between the two given MBRs according to this distance function

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

isSquared

public boolean isSquared()

Description copied from interface: DistanceFunction

Squared distances, that would become metric after square root. E.g. squared Euclidean.

Specified by:

isSquared in interface DistanceFunction<NumberVector>

Returns:

true when squared.

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

getInputTypeRestriction

public SimpleTypeInformation<? super NumberVector> getInputTypeRestriction()

Description copied from interface: DistanceFunction

Get the input data type of the function.

Specified by:

getInputTypeRestriction in interface DistanceFunction<NumberVector>

Specified by:

getInputTypeRestriction in interface PrimitiveDistanceFunction<NumberVector>

Overrides:

getInputTypeRestriction in class AbstractNumberVectorDistanceFunction

Returns:

Type restriction