org.neo4j.graphalgo.impl.centrality
Class BetweennessCentrality<ShortestPathCostType>

java.lang.Object
  org.neo4j.graphalgo.impl.centrality.ShortestPathBasedCentrality<Double,ShortestPathCostType>
      org.neo4j.graphalgo.impl.centrality.BetweennessCentrality<ShortestPathCostType>

Type Parameters:

ShortestPathCostType - The datatype used by the underlying SingleSourceShortestPath algorithm, i.e. the type the edge weights are represented by.

public class BetweennessCentrality<ShortestPathCostType>
extends ShortestPathBasedCentrality<Double,ShortestPathCostType>

Class for computing betweenness centrality as defined by Linton C. Freeman (1977) using the algorithm by Ulrik Brandes (2001).

Author:

Patrik Larsson

Field Summary

protected Double

globalFactor

Fields inherited from class org.neo4j.graphalgo.impl.centrality.ShortestPathBasedCentrality

centralities, centralityAccumulator, doneCalculation, nodeSet, singleSourceShortestPath, zeroValue

Constructor Summary

BetweennessCentrality(SingleSourceShortestPath<ShortestPathCostType> singleSourceShortestPath, Set<Node> nodeSet)
Default constructor.

Method Summary

protected Double	getAndUpdateNodeDependency(Node node, boolean skipFirstNode, Map<Node,List<Relationship>> successors, Util.PathCounter counter, Map<Node,Double> dependencies) This recursively updates the node dependencies
void	processShortestPaths(Node node, SingleSourceShortestPath<ShortestPathCostType> singleSourceShortestPath) This is the abstract method all centrality algorithms based on this class need to implement.
void	reset() The calculation is normally only done once, this resets it so it can be run again.

Methods inherited from class org.neo4j.graphalgo.impl.centrality.ShortestPathBasedCentrality

addCentralityToNode, calculate, getCentrality, setCentralityForNode

Methods inherited from class java.lang.Object

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

Field Detail

globalFactor

protected Double globalFactor

Constructor Detail

BetweennessCentrality

public BetweennessCentrality(SingleSourceShortestPath<ShortestPathCostType> singleSourceShortestPath,
                             Set<Node> nodeSet)

Default constructor.

Parameters:

singleSourceShortestPath - Underlying singleSourceShortestPath.

nodeSet - A set containing the nodes for which centrality values should be computed.

Method Detail

reset

public void reset()

Description copied from class: ShortestPathBasedCentrality

The calculation is normally only done once, this resets it so it can be run again. Also used locally for initialization.

Overrides:

reset in class ShortestPathBasedCentrality<Double,ShortestPathCostType>

getAndUpdateNodeDependency

protected Double getAndUpdateNodeDependency(Node node,
                                            boolean skipFirstNode,
                                            Map<Node,List<Relationship>> successors,
                                            Util.PathCounter counter,
                                            Map<Node,Double> dependencies)

This recursively updates the node dependencies

Parameters:

node - The start node

skipFirstNode - If true, the start node is not updated. Useful, since the first node in any path doesnt need to be updated.

successors -

counter - Object that can return the number of paths from the initial start node to any node.

dependencies - A map used to limit the recursion where possible (dynamic programming)

Returns:

processShortestPaths

public void processShortestPaths(Node node,
                                 SingleSourceShortestPath<ShortestPathCostType> singleSourceShortestPath)

Description copied from class: ShortestPathBasedCentrality

This is the abstract method all centrality algorithms based on this class need to implement. It is called once for every node in the node set, along with a SingleSourceShortestPath starting in that node.

Specified by:

processShortestPaths in class ShortestPathBasedCentrality<Double,ShortestPathCostType>