edu.uci.ics.jung.algorithms.cluster
Class EdgeBetweennessClusterer<V,E>

java.lang.Object
  edu.uci.ics.jung.algorithms.cluster.EdgeBetweennessClusterer<V,E>

All Implemented Interfaces:

org.apache.commons.collections15.Transformer<Graph<V,E>,Set<Set<V>>>

public class EdgeBetweennessClusterer<V,E>
extends Object
implements org.apache.commons.collections15.Transformer<Graph<V,E>,Set<Set<V>>>

An algorithm for computing clusters (community structure) in graphs based on edge betweenness. The betweenness of an edge is defined as the extent to which that edge lies along shortest paths between all pairs of nodes. This algorithm works by iteratively following the 2 step process:

• Compute edge betweenness for all edges in current graph
• Remove edge with highest betweenness

Running time is: O(kmn) where k is the number of edges to remove, m is the total number of edges, and n is the total number of vertices. For very sparse graphs the running time is closer to O(kn^2) and for graphs with strong community structure, the complexity is even lower.

This algorithm is a slight modification of the algorithm discussed below in that the number of edges to be removed is parameterized.

Author:

Scott White, Tom Nelson (converted to jung2)

See Also:

"Community structure in social and biological networks by Michelle Girvan and Mark Newman"

Constructor Summary

EdgeBetweennessClusterer(int numEdgesToRemove)
Constructs a new clusterer for the specified graph.

Method Summary

List<E>	getEdgesRemoved() Retrieves the list of all edges that were removed (assuming extract(...) was previously called).
Set<Set<V>>	transform(Graph<V,E> graph) Finds the set of clusters which have the strongest "community structure".

Methods inherited from class java.lang.Object

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

Constructor Detail

EdgeBetweennessClusterer

public EdgeBetweennessClusterer(int numEdgesToRemove)

Constructs a new clusterer for the specified graph.

Parameters:

numEdgesToRemove - the number of edges to be progressively removed from the graph

Method Detail

transform

public Set<Set<V>> transform(Graph<V,E> graph)

Finds the set of clusters which have the strongest "community structure". The more edges removed the smaller and more cohesive the clusters.

Specified by:

transform in interface org.apache.commons.collections15.Transformer<Graph<V,E>,Set<Set<V>>>

Parameters:

graph - the graph

getEdgesRemoved

public List<E> getEdgesRemoved()

Retrieves the list of all edges that were removed (assuming extract(...) was previously called). The edges returned are stored in order in which they were removed.

Returns:

the edges in the original graph