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

Class WeightedSquaredEuclideanDistanceFunction

java.lang.Object

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

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

All Implemented Interfaces:

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

@Alias(value="de.lmu.ifi.dbs.elki.distance.distancefunction.WeightedSquaredEuclideanDistanceFunction")
public class WeightedSquaredEuclideanDistanceFunction
extends AbstractNumberVectorDistanceFunction
implements SpatialPrimitiveDistanceFunction<NumberVector>, WeightedNumberVectorDistanceFunction<NumberVector>, Norm<NumberVector>

Weighted squared Euclidean distance for NumberVectors. This results in the same rankings as weighted Euclidean distance, but saves computing the square root.

Weighted squared Euclidean is defined as: \[ \text{Euclidean}^2_{\vec{w}}(\vec{x},\vec{y}) := \sum_i w_i (x_i-y_i)^2 \]

Since:

0.4.0

Author:

Arthur Zimek

Nested Class Summary

Nested Classes

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

Field Summary

Fields

Modifier and Type	Field and Description
protected double[]	weights Weight array

Fields inherited from interface de.lmu.ifi.dbs.elki.distance.distancefunction.WeightedNumberVectorDistanceFunction

WEIGHTS_ID

Constructor Summary

Constructors

Constructor and Description
WeightedSquaredEuclideanDistanceFunction(double[] weights) 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)
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.
double	norm(NumberVector obj) Compute the norm of object obj.

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

dimensionality, dimensionality, dimensionality, dimensionality, dimensionality, dimensionality, dimensionality, dimensionality, getInputTypeRestriction

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.PrimitiveDistanceFunction

getInputTypeRestriction

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

isMetric, isSymmetric

Field Detail

weights

protected double[] weights

Weight array

Constructor Detail

WeightedSquaredEuclideanDistanceFunction

public WeightedSquaredEuclideanDistanceFunction(double[] weights)

Constructor.

Parameters:

weights - Weight vector

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

norm

public double norm(NumberVector obj)

Description copied from interface: Norm

Compute the norm of object obj.

Specified by:

norm in interface Norm<NumberVector>

Parameters:

obj - Object

Returns:

Norm

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

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