Package elki.distance.minkowski

Class WeightedSquaredEuclideanDistance

java.lang.Object

elki.distance.AbstractNumberVectorDistance

elki.distance.minkowski.WeightedSquaredEuclideanDistance

All Implemented Interfaces:

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

public class WeightedSquaredEuclideanDistance
extends AbstractNumberVectorDistance
implements SpatialPrimitiveDistance<NumberVector>, WeightedNumberVectorDistance<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	Description
static class	WeightedSquaredEuclideanDistance.Par	Parameterization class.

Field Summary

Fields

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

Fields inherited from interface elki.distance.WeightedNumberVectorDistance

WEIGHTS_ID

Constructor Summary

Constructors

Constructor	Description
WeightedSquaredEuclideanDistance(double[] weights)	Constructor.

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)
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 elki.distance.AbstractNumberVectorDistance

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 elki.distance.Distance

isMetric, isSymmetric

Methods inherited from interface elki.distance.PrimitiveDistance

getInputTypeRestriction

Methods inherited from interface elki.distance.SpatialPrimitiveDistance

instantiate

Field Detail

weights

protected double[] weights

Weight array

Constructor Detail

WeightedSquaredEuclideanDistance

public WeightedSquaredEuclideanDistance(double[] weights)

Constructor.

Parameters:

weights - Weight vector

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

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: 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

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