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

Class CanberraDistanceFunction

java.lang.Object

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

All Implemented Interfaces:

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

@Priority(value=200)
 @Reference(authors="G. N. Lance, W. T. Williams",
           title="Computer Programs for Hierarchical Polythetic Classification (Similarity Analyses)",
           booktitle="Computer Journal, Volume 9, Issue 1",
           url="https://doi.org/10.1093/comjnl/9.1.60",
           bibkey="doi:10.1093/comjnl/9.1.60")
 @Alias(value="canberra")
public class CanberraDistanceFunction
extends java.lang.Object
implements SpatialPrimitiveDistanceFunction<NumberVector>, NumberVectorDistanceFunction<NumberVector>

Canberra distance function, a variation of Manhattan distance.

Canberra distance is defined as: \[ \text{Canberra}(\vec{x},\vec{y}) := \sum\nolimits_i \tfrac{|x_i-y_i|}{|x_i|+|y_i|} \]

Reference:
G. N. Lance, W. T. Williams
Computer Programs for Hierarchical Polythetic Classification ("Similarity Analyses")
In: Computer Journal, Volume 9, Issue 1

Since:

0.5.0

Author:

Erich Schubert

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	CanberraDistanceFunction.Parameterizer Parameterization class.

Field Summary

Fields

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

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	CanberraDistanceFunction() Constructor.

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	isMetric() Is this distance function metric (satisfy the triangle inequality)
double	minDist(SpatialComparable mbr1, SpatialComparable mbr2) Computes the distance between the two given MBRs according to this distance function.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, 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

isSquared, isSymmetric

Field Detail

STATIC

public static final CanberraDistanceFunction STATIC

Static instance. Use this!

Constructor Detail

CanberraDistanceFunction

protected CanberraDistanceFunction()

Constructor.

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

isMetric

public boolean isMetric()

Description copied from interface: DistanceFunction

Is this distance function metric (satisfy the triangle inequality)

Specified by:

isMetric in interface DistanceFunction<NumberVector>

Returns:

true when metric.

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>

Returns:

Type restriction

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