Class StrongConnectivityInspector<V,E>

java.lang.Object
org.jgrapht.alg.StrongConnectivityInspector<V,E>

public class StrongConnectivityInspector<V,E> extends Object

Complements the ConnectivityInspector class with the capability to compute the strongly connected components of a directed graph. The algorithm is implemented after "Cormen et al: Introduction to agorithms", Chapter 22.5. It has a running time of O(V + E).

Unlike ConnectivityInspector, this class does not implement incremental inspection. The full algorithm is executed at the first call of stronglyConnectedSets() or isStronglyConnected().

Since:
Feb 2, 2005
Author:
Christian Soltenborn, Christian Hammer
  • Constructor Details

    • StrongConnectivityInspector

      public StrongConnectivityInspector(DirectedGraph<V,E> directedGraph)
      The constructor of the StrongConnectivityInspector class.
      Parameters:
      directedGraph - the graph to inspect
      Throws:
      IllegalArgumentException
  • Method Details

    • getGraph

      public DirectedGraph<V,E> getGraph()
      Returns the graph inspected by the StrongConnectivityInspector.
      Returns:
      the graph inspected by this StrongConnectivityInspector
    • isStronglyConnected

      public boolean isStronglyConnected()
      Returns true if the graph of this StronglyConnectivityInspector instance is strongly connected.
      Returns:
      true if the graph is strongly connected, false otherwise
    • stronglyConnectedSets

      public List<Set<V>> stronglyConnectedSets()
      Computes a List of Sets, where each set contains vertices which together form a strongly connected component within the given graph.
      Returns:
      List of Set s containing the strongly connected components
    • stronglyConnectedSubgraphs

      public List<DirectedSubgraph<V,E>> stronglyConnectedSubgraphs()

      Computes a list of DirectedSubgraphs of the given graph. Each subgraph will represent a strongly connected component and will contain all vertices of that component. The subgraph will have an edge (u,v) iff u and v are contained in the strongly connected component.

      NOTE: Calling this method will first execute stronglyConnectedSets(). If you don't need subgraphs, use that method.

      Returns:
      a list of subgraphs representing the strongly connected components