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

Class SparseSquaredEuclideanDistanceFunction

java.lang.Object

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

All Implemented Interfaces:

DistanceFunction<SparseNumberVector>, Norm<SparseNumberVector>, PrimitiveDistanceFunction<SparseNumberVector>

public class SparseSquaredEuclideanDistanceFunction
extends java.lang.Object
implements PrimitiveDistanceFunction<SparseNumberVector>, Norm<SparseNumberVector>

Squared Euclidean distance function, optimized for SparseNumberVectors.

Squared Euclidean distance is defined as: \[ \text{Euclidean}^2(\vec{x},\vec{y}) := \sum\nolimits_i (x_i-y_i)^2 \]

For sparse vectors, we can skip those i where both vectors are 0.

Since:

0.7.5

Author:

Erich Schubert

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	SparseSquaredEuclideanDistanceFunction.Parameterizer Parameterizer

Field Summary

Fields

Modifier and Type	Field and Description
static SparseSquaredEuclideanDistanceFunction	STATIC Static instance

Constructor Summary

Constructors

Constructor and Description
SparseSquaredEuclideanDistanceFunction() Deprecated. Use static instance instead.

Method Summary

Modifier and Type	Method and Description
double	distance(SparseNumberVector v1, SparseNumberVector v2) Computes the distance between two given DatabaseObjects according to this distance function.
SimpleTypeInformation<? super SparseNumberVector>	getInputTypeRestriction() Get the input data type of the function.
boolean	isMetric() Is this distance function metric (satisfy the triangle inequality)
boolean	isSquared() Squared distances, that would become metric after square root.
double	norm(SparseNumberVector v1) Compute the norm of object obj.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, 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

isSymmetric

Field Detail

STATIC

public static final SparseSquaredEuclideanDistanceFunction STATIC

Static instance

Constructor Detail

SparseSquaredEuclideanDistanceFunction

@Deprecated
public SparseSquaredEuclideanDistanceFunction()

Deprecated. Use static instance instead.

Constructor - use STATIC instead.

Method Detail

distance

public double distance(SparseNumberVector v1,
                       SparseNumberVector v2)

Description copied from interface: PrimitiveDistanceFunction

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

Specified by:

distance in interface PrimitiveDistanceFunction<SparseNumberVector>

Parameters:

v1 - first DatabaseObject

v2 - second DatabaseObject

Returns:

the distance between two given DatabaseObjects according to this distance function

norm

public double norm(SparseNumberVector v1)

Description copied from interface: Norm

Compute the norm of object obj.

Specified by:

norm in interface Norm<SparseNumberVector>

Parameters:

v1 - Object

Returns:

Norm

getInputTypeRestriction

public SimpleTypeInformation<? super SparseNumberVector> getInputTypeRestriction()

Description copied from interface: DistanceFunction

Get the input data type of the function.

Specified by:

getInputTypeRestriction in interface DistanceFunction<SparseNumberVector>

Specified by:

getInputTypeRestriction in interface PrimitiveDistanceFunction<SparseNumberVector>

Returns:

Type restriction

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<SparseNumberVector>

Returns:

true when squared.

isMetric

public boolean isMetric()

Description copied from interface: DistanceFunction

Is this distance function metric (satisfy the triangle inequality)

Specified by:

isMetric in interface DistanceFunction<SparseNumberVector>

Returns:

true when metric.