Package elki.distance.probabilistic

Class ChiSquaredDistance

java.lang.Object

elki.distance.AbstractNumberVectorDistance

elki.distance.probabilistic.ChiSquaredDistance

All Implemented Interfaces:

Distance<NumberVector>, NumberVectorDistance<NumberVector>, PrimitiveDistance<NumberVector>, SpatialPrimitiveDistance<NumberVector>

Direct Known Subclasses:

ChiDistance

@Alias("chisq")
@Priority(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 ChiSquaredDistance
extends AbstractNumberVectorDistance
implements SpatialPrimitiveDistance<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	Description
static class	ChiSquaredDistance.Par	Parameterization class, using the static instance.

Field Summary

Fields

Modifier and Type	Field	Description
static ChiSquaredDistance	STATIC	Static instance.

Constructor Summary

Constructors

Constructor	Description
ChiSquaredDistance()	Deprecated. Use static instance!

Method Summary

Modifier and Type	Method	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 elki.distance.AbstractNumberVectorDistance

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 elki.distance.Distance

isMetric, isSymmetric

Methods inherited from interface elki.distance.SpatialPrimitiveDistance

instantiate

Field Detail

STATIC

public static final ChiSquaredDistance STATIC

Static instance. Use this!

Constructor Detail

ChiSquaredDistance

@Deprecated
public ChiSquaredDistance()

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: PrimitiveDistance

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

Specified by:

distance in interface NumberVectorDistance<NumberVector>

Specified by:

distance in interface PrimitiveDistance<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: SpatialPrimitiveDistance

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

Specified by:

minDist in interface SpatialPrimitiveDistance<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: Distance

Squared distances, that would become metric after square root.

E.g. squared Euclidean.

Specified by:

isSquared in interface Distance<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: Distance

Get the input data type of the function.

Specified by:

getInputTypeRestriction in interface Distance<NumberVector>

Specified by:

getInputTypeRestriction in interface PrimitiveDistance<NumberVector>

Overrides:

getInputTypeRestriction in class AbstractNumberVectorDistance

Returns:

Type restriction