de.lmu.ifi.dbs.elki.algorithm.clustering.hierarchical

Class WardLinkageMethod

java.lang.Object

de.lmu.ifi.dbs.elki.algorithm.clustering.hierarchical.WardLinkageMethod

All Implemented Interfaces:

LinkageMethod

@Reference(authors="J. H. Ward Jr",
           title="Hierarchical grouping to optimize an objective function",
           booktitle="Journal of the American statistical association 58.301",
           url="http://dx.doi.org/10.1080/01621459.1963.10500845")
@Alias(value={"ward","variance"})
public class WardLinkageMethod
extends Object
implements LinkageMethod

Ward's method clustering method. This criterion minimizes variances, and makes most sense when used with squared Euclidean distance, see SquaredEuclideanDistanceFunction Reference:

Ward Jr, Joe H.
Hierarchical grouping to optimize an objective function
Journal of the American statistical association 58.301 (1963): 236-244.

Since:

0.6.0

Author:

Erich Schubert

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	WardLinkageMethod.Parameterizer Class parameterizer.

Field Summary

Fields

Modifier and Type	Field and Description
static WardLinkageMethod	STATIC Static instance of class.

Constructor Summary

Constructors

Constructor and Description
WardLinkageMethod() Deprecated. use the static instance STATIC instead.

Method Summary

Methods

Modifier and Type	Method and Description
double	combine(int sizex, double dx, int sizey, double dy, int sizej, double dxy) Compute combined linkage for two clusters.

Methods inherited from class java.lang.Object

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

Field Detail

STATIC

public static final WardLinkageMethod STATIC

Static instance of class.

Constructor Detail

WardLinkageMethod

@Deprecated
public WardLinkageMethod()

Deprecated. use the static instance STATIC instead.

Constructor.

Method Detail

combine

public double combine(int sizex,
             double dx,
             int sizey,
             double dy,
             int sizej,
             double dxy)

Description copied from interface: LinkageMethod

Compute combined linkage for two clusters.

Specified by:

combine in interface LinkageMethod

Parameters:

sizex - Size of first cluster x before merging

dx - Distance of cluster x to j before merging

sizey - Size of second cluster y before merging

dy - Distance of cluster y to j before merging

sizej - Size of candidate cluster j

dxy - Distance between clusters x and y before merging

Returns:

Combined distance