Package edu.uci.ics.jung.algorithms.shortestpath

Class DijkstraShortestPath<V,E>

java.lang.Object
edu.uci.ics.jung.algorithms.shortestpath.DijkstraDistance<V,E>
edu.uci.ics.jung.algorithms.shortestpath.DijkstraShortestPath<V,E>
All Implemented Interfaces:
Distance<V>, ShortestPath<V,E>
public class DijkstraShortestPath<V,E> extends DijkstraDistance<V,E> implements ShortestPath<V,E>

Calculates distances and shortest paths using Dijkstra's single-source-shortest-path algorithm. This is a lightweight extension of DijkstraDistance that also stores path information, so that the shortest paths can be reconstructed.

The elements in the maps returned by getIncomingEdgeMap are ordered (that is, returned by the iterator) by nondecreasing distance from source.

Author:
Joshua O'Madadhain, Tom Nelson converted to jung2
See Also:

  • Constructor Details

    • DijkstraShortestPath

      public DijkstraShortestPath(Graph<V,E> g, com.google.common.base.Function<E,? extends Number> nev, boolean cached)

      Creates an instance of DijkstraShortestPath for the specified graph and the specified method of extracting weights from edges, which caches results locally if and only if cached is true.

      Parameters:
      g - the graph on which distances will be calculated
      nev - the class responsible for returning weights for edges
      cached - specifies whether the results are to be cached

    • DijkstraShortestPath

      public DijkstraShortestPath(Graph<V,E> g, com.google.common.base.Function<E,? extends Number> nev)

      Creates an instance of DijkstraShortestPath for the specified graph and the specified method of extracting weights from edges, which caches results locally.

      Parameters:
      g - the graph on which distances will be calculated
      nev - the class responsible for returning weights for edges

    • DijkstraShortestPath

      public DijkstraShortestPath(Graph<V,E> g)

      Creates an instance of DijkstraShortestPath for the specified unweighted graph (that is, all weights 1) which caches results locally.

      Parameters:
      g - the graph on which distances will be calculated

    • DijkstraShortestPath

      public DijkstraShortestPath(Graph<V,E> g, boolean cached)

      Creates an instance of DijkstraShortestPath for the specified unweighted graph (that is, all weights 1) which caches results locally.

      Parameters:
      g - the graph on which distances will be calculated
      cached - specifies whether the results are to be cached

  • Method Details

    • getSourceData

      protected DijkstraDistance<V,E>.SourceData getSourceData(V source)
      Overrides:
      getSourceData in class DijkstraDistance<V,E>

    • getIncomingEdge

      public E getIncomingEdge(V source, V target)

      Returns the last edge on a shortest path from source to target, or null if target is not reachable from source.

      If either vertex is not in the graph for which this instance was created, throws IllegalArgumentException.

      Parameters:
      source - the vertex where the shortest path starts
      target - the vertex where the shortest path ends
      Returns:
      the last edge on a shortest path from source to target or null if target is not reachable from source

    • getIncomingEdgeMap

      public Map<V,E> getIncomingEdgeMap(V source)

      Returns a LinkedHashMap which maps each vertex in the graph (including the source vertex) to the last edge on the shortest path from the source vertex. The map's iterator will return the elements in order of increasing distance from source.

      Specified by:
      getIncomingEdgeMap in interface ShortestPath<V,E>
      Parameters:
      source - the vertex from which distances are measured
      Returns:
      a map from vertices to the last edge on the shortest path to that vertex starting from source
      See Also:

    • getPath

      public List<E> getPath(V source, V target)
      Returns a List of the edges on the shortest path from source to target, in order of their occurrence on this path. If either vertex is not in the graph for which this instance was created, throws IllegalArgumentException.
      Parameters:
      source - the starting vertex for the path to generate
      target - the ending vertex for the path to generate
      Returns:
      the edges on the shortest path from source to target, in order of their occurrence

    • getIncomingEdgeMap

      public LinkedHashMap<V,E> getIncomingEdgeMap(V source, int numDests)

      Returns a LinkedHashMap which maps each of the closest numDests vertices to the source vertex in the graph (including the source vertex) to the incoming edge along the path from that vertex. Throws an IllegalArgumentException if source is not in this instance's graph, or if numDests is either less than 1 or greater than the number of vertices in the graph.

      Parameters:
      source - the vertex from which distances are measured
      numDests - the number of vertices for which to measure distances
      Returns:
      a map from each of the closest numDests vertices to the last edge on the shortest path to that vertex starting from source
      See Also: