Package elki.distance.set

Class HammingDistance

java.lang.Object

elki.distance.set.AbstractSetDistance<FeatureVector<?>>

elki.distance.set.HammingDistance

All Implemented Interfaces:

Distance<FeatureVector<?>>, NumberVectorDistance<FeatureVector<?>>, PrimitiveDistance<FeatureVector<?>>

@Reference(authors="R. W. Hamming",
           title="Error detecting and error correcting codes",
           booktitle="Bell System technical journal, 29(2)",
           url="https://doi.org/10.1002/j.1538-7305.1950.tb00463.x",
           bibkey="doi:10.1002/j.1538-7305.1950.tb00463.x")
public class HammingDistance
extends AbstractSetDistance<FeatureVector<?>>
implements NumberVectorDistance<FeatureVector<?>>

Computes the Hamming distance of arbitrary vectors - i.e. counting, on how many places they differ.

Reference:

R. W. Hamming
Error detecting and error correcting codes
Bell System technical journal, 29(2)

TODO: add a sparse (but not binary) optimized version?

Since:

0.7.0

Author:

Erich Schubert

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	HammingDistance.Par	Parameterization class.

Field Summary

Fields

Modifier and Type	Field	Description
static HammingDistance	STATIC	Static instance.

Fields inherited from class elki.distance.set.AbstractSetDistance

DOUBLE_NULL, INTEGER_NULL, STRING_NULL

Constructor Summary

Constructors

Constructor	Description
HammingDistance()

Method Summary

Modifier and Type	Method	Description
double	distance(FeatureVector<?> o1, FeatureVector<?> o2)	Computes the distance between two given DatabaseObjects according to this distance function.
double	distance(NumberVector o1, NumberVector o2)	Computes the distance between two given vectors according to this distance function.
boolean	equals(java.lang.Object obj)
SimpleTypeInformation<? super FeatureVector<?>>	getInputTypeRestriction()	Get the input data type of the function.
private double	hammingDistanceNumberVector(NumberVector o1, NumberVector o2)	Version for number vectors.
int	hashCode()
boolean	isMetric()	Is this distance function metric (satisfy the triangle inequality)

Methods inherited from class elki.distance.set.AbstractSetDistance

isNull

Methods inherited from class java.lang.Object

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

Methods inherited from interface elki.distance.Distance

isSquared, isSymmetric

Methods inherited from interface elki.distance.PrimitiveDistance

instantiate

Field Detail

STATIC

public static final HammingDistance STATIC

Static instance.

Constructor Detail

HammingDistance

public HammingDistance()

Method Detail

isMetric

public boolean isMetric()

Description copied from interface: Distance

Is this distance function metric (satisfy the triangle inequality)

Specified by:

isMetric in interface Distance<FeatureVector<?>>

Returns:

true when metric.

distance

public double distance(FeatureVector<?> o1,
                       FeatureVector<?> o2)

Description copied from interface: PrimitiveDistance

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

Specified by:

distance in interface PrimitiveDistance<FeatureVector<?>>

Parameters:

o1 - first DatabaseObject

o2 - second DatabaseObject

Returns:

the distance between two given DatabaseObjects according to this distance function

distance

public double distance(NumberVector o1,
                       NumberVector o2)

Description copied from interface: NumberVectorDistance

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

Specified by:

distance in interface NumberVectorDistance<FeatureVector<?>>

Parameters:

o1 - first vector

o2 - second vector

Returns:

the distance between two given vectors according to this distance function

hammingDistanceNumberVector

private double hammingDistanceNumberVector(NumberVector o1,
                                           NumberVector o2)

Version for number vectors.

Parameters:

o1 - First vector

o2 - Second vector

Returns:

hamming distance

getInputTypeRestriction

public SimpleTypeInformation<? super FeatureVector<?>> getInputTypeRestriction()

Description copied from interface: Distance

Get the input data type of the function.

Specified by:

getInputTypeRestriction in interface Distance<FeatureVector<?>>

Specified by:

getInputTypeRestriction in interface PrimitiveDistance<FeatureVector<?>>

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