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

Class BidirectionalDijkstraShortestPath<V,E>

java.lang.Object
org.jgrapht.alg.shortestpath.BaseBidirectionalShortestPathAlgorithm<V,E>
org.jgrapht.alg.shortestpath.BidirectionalDijkstraShortestPath<V,E>
Type Parameters:
V - the graph vertex type
E - the graph edge type
All Implemented Interfaces:
ShortestPathAlgorithm<V,E>
public final class BidirectionalDijkstraShortestPath<V,E> extends BaseBidirectionalShortestPathAlgorithm<V,E>
A bidirectional version of Dijkstra's algorithm.

See the Wikipedia article for details and references about bidirectional search. This technique does not change the worst-case behavior of the algorithm but reduces, in some cases, the number of visited vertices in practice. This implementation alternatively constructs forward and reverse paths from the source and target vertices respectively.

This iterator can use a custom heap implementation, which can specified during the construction time. Pairing heap is used by default

Author:
Dimitrios Michail
See Also:

  • 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

    • BidirectionalDijkstraShortestPath

      public BidirectionalDijkstraShortestPath(Graph<V,E> graph)
      Constructs a new instance for a specified graph.
      Parameters:
      graph - the input graph

    • BidirectionalDijkstraShortestPath

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

    • BidirectionalDijkstraShortestPath

      public BidirectionalDijkstraShortestPath(Graph<V,E> graph, double radius)
      Constructs a new instance for a specified graph.
      Parameters:
      graph - the input graph
      radius - limit on path length, or Double.POSITIVE_INFINITY for unbounded search

    • BidirectionalDijkstraShortestPath

      public BidirectionalDijkstraShortestPath(Graph<V,E> graph, double radius, Supplier<org.jheaps.AddressableHeap<Double,Pair<V,E>>> heapSupplier)
      Constructs a new instance for a specified graph. The constructed algorithm will use the heap supplied by the heapSupplier.
      Parameters:
      graph - the input 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), 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)
      Description copied from interface: ShortestPathAlgorithm
      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.
      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