Package elki.distance.minkowski

Class SparseSquaredEuclideanDistance

java.lang.Object

elki.distance.minkowski.SparseSquaredEuclideanDistance

All Implemented Interfaces:

Distance<SparseNumberVector>, Norm<SparseNumberVector>, PrimitiveDistance<SparseNumberVector>

public class SparseSquaredEuclideanDistance
extends java.lang.Object
implements PrimitiveDistance<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	Description
static class	SparseSquaredEuclideanDistance.Par	Parameterizer

Field Summary

Fields

Modifier and Type	Field	Description
static SparseSquaredEuclideanDistance	STATIC	Static instance

Constructor Summary

Constructors

Constructor	Description
SparseSquaredEuclideanDistance()	Deprecated. Use static instance instead.

Method Summary

Modifier and Type	Method	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 elki.distance.Distance

isSymmetric

Methods inherited from interface elki.distance.PrimitiveDistance

instantiate

Field Detail

STATIC

public static final SparseSquaredEuclideanDistance STATIC

Static instance

Constructor Detail

SparseSquaredEuclideanDistance

@Deprecated
public SparseSquaredEuclideanDistance()

Deprecated.

Use static instance instead.

Constructor - use STATIC instead.

Method Detail

distance

public double distance(SparseNumberVector v1,
                       SparseNumberVector v2)

Description copied from interface: PrimitiveDistance

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

Specified by:

distance in interface PrimitiveDistance<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: Distance

Get the input data type of the function.

Specified by:

getInputTypeRestriction in interface Distance<SparseNumberVector>

Specified by:

getInputTypeRestriction in interface PrimitiveDistance<SparseNumberVector>

Returns:

Type restriction

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<SparseNumberVector>

Returns:

true when squared.

isMetric

public boolean isMetric()

Description copied from interface: Distance

Is this distance function metric (satisfy the triangle inequality)

Specified by:

isMetric in interface Distance<SparseNumberVector>

Returns:

true when metric.