Module org.jgrapht.core
Package org.jgrapht.alg.scoring

Class ClosenessCentrality<V,​E>

java.lang.Object
org.jgrapht.alg.scoring.ClosenessCentrality<V,​E>
Type Parameters:
V - the graph vertex type
E - the graph edge type
All Implemented Interfaces:
VertexScoringAlgorithm<V,​java.lang.Double>
Direct Known Subclasses:
HarmonicCentrality
public class ClosenessCentrality<V,​E>
extends java.lang.Object
implements VertexScoringAlgorithm<V,​java.lang.Double>
Closeness centrality.

Computes the closeness centrality of each vertex of a graph. The closeness of a vertex $x$ is defined as the reciprocal of the farness, that is $H(x)= 1 / \sum_{y \neq x} d(x,y)$, where $d(x,y)$ is the shortest path distance from $x$ to $y$. When normalization is used, the score is multiplied by $n-1$ where $n$ is the total number of vertices in the graph. For more details see wikipedia and

  • Alex Bavelas. Communication patterns in task-oriented groups. J. Acoust. Soc. Am, 22(6):725–730, 1950.

This implementation computes by default the closeness centrality using outgoing paths and normalizes the scores. This behavior can be adjusted by the constructor arguments.

When the graph is disconnected, the closeness centrality score equals $0$ for all vertices. In the case of weakly connected digraphs, the closeness centrality of several vertices might be 0. See HarmonicCentrality for a different approach in case of disconnected graphs.

Shortest paths are computed either by using Dijkstra's algorithm or Floyd-Warshall depending on whether the graph has edges with negative edge weights. Thus, the running time is either $O(n (m +n \log n))$ or $O(n^3)$ respectively, where $n$ is the number of vertices and $m$ the number of edges of the graph.

Author:
Dimitrios Michail

  • Field Summary

    Fields 
    Modifier and Type Field Description
    protected Graph<V,​E> graph
    Underlying graph
    protected boolean incoming
    Whether to use incoming or outgoing paths
    protected boolean normalize
    Whether to normalize scores
    protected java.util.Map<V,​java.lang.Double> scores
    The actual scores

  • Constructor Summary

    Constructors 
    Constructor Description
    ClosenessCentrality​(Graph<V,​E> graph)
    Construct a new instance.
    ClosenessCentrality​(Graph<V,​E> graph, boolean incoming, boolean normalize)
    Construct a new instance.

  • Method Summary

    Modifier and Type Method Description
    protected void compute()
    Compute the centrality index
    java.util.Map<V,​java.lang.Double> getScores()
    Get a map with the scores of all vertices
    protected ShortestPathAlgorithm<V,​E> getShortestPathAlgorithm()
    Get the shortest path algorithm for the paths computation.
    java.lang.Double getVertexScore​(V v)
    Get a vertex score

    Methods inherited from class java.lang.Object

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

  • Field Details

    • graph

      protected final Graph<V,​E> graph
      Underlying graph

    • incoming

      protected final boolean incoming
      Whether to use incoming or outgoing paths

    • normalize

      protected final boolean normalize
      Whether to normalize scores

    • scores

      protected java.util.Map<V,​java.lang.Double> scores
      The actual scores

  • Constructor Details

    • ClosenessCentrality

      public ClosenessCentrality​(Graph<V,​E> graph)
      Construct a new instance. By default the centrality is normalized and computed using outgoing paths.
      Parameters:
      graph - the input graph

    • ClosenessCentrality

      public ClosenessCentrality​(Graph<V,​E> graph, boolean incoming, boolean normalize)
      Construct a new instance.
      Parameters:
      graph - the input graph
      incoming - if true incoming paths are used, otherwise outgoing paths
      normalize - whether to normalize by multiplying the closeness by $n-1$, where $n$ is the number of vertices of the graph

  • Method Details