Module org.jgrapht.core
Package org.jgrapht.alg.shortestpath

Class DijkstraShortestPath<V,E>

java.lang.Object
org.jgrapht.alg.shortestpath.DijkstraShortestPath<V,E>
Type Parameters:
V - the graph vertex type
E - the graph edge type
All Implemented Interfaces:
ShortestPathAlgorithm<V,E>
public final class DijkstraShortestPath<V,E> extends Object
An implementation of Dijkstra's shortest path algorithm using a pairing heap by default. A custom heap implementation can by specified during the construction time.
Author:
John V. Sichi

  • Field Details

    • GRAPH_CONTAINS_A_NEGATIVE_WEIGHT_CYCLE

      protected static final String GRAPH_CONTAINS_A_NEGATIVE_WEIGHT_CYCLE
      Error message for reporting the existence of a negative-weight cycle.
      See Also:

    • GRAPH_MUST_CONTAIN_THE_SOURCE_VERTEX

      protected static final String GRAPH_MUST_CONTAIN_THE_SOURCE_VERTEX
      Error message for reporting that a source vertex is missing.
      See Also:

    • GRAPH_MUST_CONTAIN_THE_SINK_VERTEX

      protected static final String GRAPH_MUST_CONTAIN_THE_SINK_VERTEX
      Error message for reporting that a sink vertex is missing.
      See Also:

    • graph

      protected final Graph<V,E> graph
      The underlying graph.

  • Constructor Details

    • DijkstraShortestPath

      public DijkstraShortestPath(Graph<V,E> graph)
      Constructs a new instance of the algorithm for a given graph. The constructed algorithm will use pairing heap as a default heap implementation.
      Parameters:
      graph - the graph

    • DijkstraShortestPath

      public DijkstraShortestPath(Graph<V,E> graph, double radius)
      Constructs a new instance of the algorithm for a given graph. The constructed algorithm will use pairing heap as a default heap implementation.
      Parameters:
      graph - the graph
      radius - limit on path length, or Double.POSITIVE_INFINITY for unbounded search

    • DijkstraShortestPath

      public DijkstraShortestPath(Graph<V,E> graph, Supplier<org.jheaps.AddressableHeap<Double,Pair<V,E>>> heapSupplier)
      Constructs a new instance of the algorithm for a given graph. The constructed algorithm will use the heap supplied by the heapSupplier
      Parameters:
      graph - the graph
      heapSupplier - supplier of the preferable heap implementation

    • DijkstraShortestPath

      public DijkstraShortestPath(Graph<V,E> graph, double radius, Supplier<org.jheaps.AddressableHeap<Double,Pair<V,E>>> heapSupplier)
      Constructs a new instance of the algorithm for a given graph.
      Parameters:
      graph - the graph
      radius - limit on path length, or Double.POSITIVE_INFINITY for unbounded search
      heapSupplier - supplier of the preferable heap implementation

  • Method Details

    • findPathBetween

      public static <V, E> GraphPath<V,E> findPathBetween(Graph<V,E> graph, V source, V sink)
      Find a path between two vertices. For a more advanced search (e.g. limited by radius or using another heap), use the constructor instead.
      Type Parameters:
      V - the graph vertex type
      E - the graph edge type
      Parameters:
      graph - the graph to be searched
      source - the vertex at which the path should start
      sink - the vertex at which the path should end
      Returns:
      a shortest path, or null if no path exists

    • getPath

      public GraphPath<V,E> getPath(V source, V sink)
      Get a shortest path from a source vertex to a sink vertex.
      Parameters:
      source - the source vertex
      sink - the target vertex
      Returns:
      a shortest path or null if no path exists

    • getPaths

      public ShortestPathAlgorithm.SingleSourcePaths<V,E> getPaths(V source)
      Compute all shortest paths starting from a single source vertex.

      Note that in the case of Dijkstra's algorithm it is more efficient to compute all single-source shortest paths using this method than repeatedly invoking getPath(Object, Object) for the same source but different sink vertex.

      Specified by:
      getPaths in interface ShortestPathAlgorithm<V,E>
      Parameters:
      source - the source vertex
      Returns:
      the shortest paths

    • getPathWeight

      public double getPathWeight(V source, V sink)
      Get the weight of the shortest path from a source vertex to a sink vertex. Returns Double.POSITIVE_INFINITY if no path exists.
      Specified by:
      getPathWeight in interface ShortestPathAlgorithm<V,E>
      Parameters:
      source - the source vertex
      sink - the sink vertex
      Returns:
      the weight of the shortest path from a source vertex to a sink vertex, or Double.POSITIVE_INFINITY if no path exists

    • createEmptyPath

      protected final GraphPath<V,E> createEmptyPath(V source, V sink)
      Create an empty path. Returns null if the source vertex is different than the target vertex.
      Parameters:
      source - the source vertex
      sink - the sink vertex
      Returns:
      an empty path or null null if the source vertex is different than the target vertex