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

Class SingleLinkage

java.lang.Object

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

All Implemented Interfaces:

Linkage

@Reference(authors="K. Florek, J. \u0141ukaszewicz, J. Perkal, H. Steinhaus, S. Zubrzycki",
           title="Sur la liaison et la division des points d\'un ensemble fini",
           booktitle="Colloquium Mathematicae 2(3-4)",
           bibkey="journals/misc/FlorekLPSZ51")
 @Alias(value={"single-link","single","slink","nearest","nearest-neighbor","de.lmu.ifi.dbs.elki.algorithm.clustering.hierarchical.SingleLinkageMethod"})
 @Priority(value=100)
public class SingleLinkage
extends java.lang.Object
implements Linkage

Single-linkage ("minimum") clustering method.

The distance of two clusters is simply the minimum of all pairwise distances between the two clusters.

The distance of two clusters is defined as: \[d_{\min}(A,B):=\min_{a\in A}\min_{b\in B} d(a,b)\]

This can be computed recursively using: \[d_{\min}(A\cup B,C) = \min(d(A,C), d(B,C))\]

Note that with similarity functions, one would need to use the maximum instead to get the same effect.

Reference:

K. Florek, J. Łukaszewicz, J. Perkal, H. Steinhaus, S. Zubrzycki
Sur la liaison et la division des points d'un ensemble fini
Colloquium Mathematicae 2(3-4)

Since:

0.6.0

Author:

Erich Schubert

Nested Class Summary

Nested Classes

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

Field Summary

Fields

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

Constructor Summary

Constructors

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

Method Summary

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

Methods inherited from interface de.lmu.ifi.dbs.elki.algorithm.clustering.hierarchical.linkage.Linkage

initial, restore

Field Detail

STATIC

public static final SingleLinkage STATIC

Static instance of class.

Constructor Detail

SingleLinkage

@Deprecated
public SingleLinkage()

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: Linkage

Compute combined linkage for two clusters.

Specified by:

combine in interface Linkage

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