- Type Parameters:
E
- the graph edge type
- All Implemented Interfaces:
ShortestPathAlgorithm<Integer,
E>
This class avoids using hash tables when the vertices are numbered from $0$ to $n-1$ where $n$ is the number of vertices of the graph. If vertices are not in this range, then they are mapped in this range using an open addressing hash table (linear probing).
This implementation should be faster than our more generic one which is
DijkstraShortestPath
since it avoids the extensive use of hash tables.
By default a 4-ary heap is used. The user is free to use a custom heap implementation during construction time. Regarding the choice of heap, it is generally known that it depends on the particular workload. For more details and experiments which can help someone make the choice, read the following paper: Larkin, Daniel H., Siddhartha Sen, and Robert E. Tarjan. "A back-to-basics empirical study of priority queues." 2014 Proceedings of the Sixteenth Workshop on Algorithm Engineering and Experiments (ALENEX). Society for Industrial and Applied Mathematics, 2014.
-
Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionprivate class
The actual implementation class.private class
private class
A very special case linear probing hash table, fit for this particular use case.Nested classes/interfaces inherited from interface org.jgrapht.alg.interfaces.ShortestPathAlgorithm
ShortestPathAlgorithm.SingleSourcePaths<V,
E> -
Field Summary
FieldsModifier and TypeFieldDescriptionFields inherited from class org.jgrapht.alg.shortestpath.BaseShortestPathAlgorithm
graph, GRAPH_CONTAINS_A_NEGATIVE_WEIGHT_CYCLE, GRAPH_MUST_CONTAIN_THE_SINK_VERTEX, GRAPH_MUST_CONTAIN_THE_SOURCE_VERTEX
-
Constructor Summary
ConstructorsConstructorDescriptionIntVertexDijkstraShortestPath
(Graph<Integer, E> graph) Constructs a new instance of the algorithm for a given graph.IntVertexDijkstraShortestPath
(Graph<Integer, E> graph, Supplier<org.jheaps.AddressableHeap<Double, Integer>> heapSupplier) Constructs a new instance of the algorithm for a given graph. -
Method Summary
Modifier and TypeMethodDescriptionfindPathBetween
(Graph<Integer, E> graph, Integer source, Integer sink) Find a path between two vertices.Get a shortest path from a source vertex to a sink vertex.Compute all shortest paths starting from a single source vertex.Methods inherited from class org.jgrapht.alg.shortestpath.BaseShortestPathAlgorithm
createEmptyPath, getPathWeight
-
Field Details
-
heapSupplier
-
-
Constructor Details
-
IntVertexDijkstraShortestPath
Constructs a new instance of the algorithm for a given graph.- Parameters:
graph
- the graph
-
IntVertexDijkstraShortestPath
public IntVertexDijkstraShortestPath(Graph<Integer, E> graph, Supplier<org.jheaps.AddressableHeap<Double, Integer>> heapSupplier) Constructs a new instance of the algorithm for a given graph.- Parameters:
graph
- the graphheapSupplier
- supplier of the preferable heap implementation
-
-
Method Details
-
findPathBetween
public static <E> GraphPath<Integer,E> findPathBetween(Graph<Integer, E> graph, Integer source, Integer sink) Find a path between two vertices. For a more advanced search (e.g. using another heap), use the constructor instead.- Type Parameters:
E
- the graph edge type- Parameters:
graph
- the graph to be searchedsource
- the vertex at which the path should startsink
- the vertex at which the path should end- Returns:
- a shortest path, or null if no path exists
-
getPath
Description copied from interface:ShortestPathAlgorithm
Get a shortest path from a source vertex to a sink vertex.- Parameters:
source
- the source vertexsink
- the target vertex- Returns:
- a shortest path or null if no path exists
-
getPaths
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(Integer, Integer)
for the same source but different sink vertex.- Specified by:
getPaths
in interfaceShortestPathAlgorithm<Integer,
E> - Overrides:
getPaths
in classBaseShortestPathAlgorithm<Integer,
E> - Parameters:
source
- the source vertex- Returns:
- the shortest paths
-