- java.lang.Object
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- org.jgrapht.alg.shortestpath.BaseShortestPathAlgorithm<java.lang.Integer,E>
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- org.jgrapht.alg.shortestpath.IntVertexDijkstraShortestPath<E>
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- Type Parameters:
E
- the graph edge type
- All Implemented Interfaces:
ShortestPathAlgorithm<java.lang.Integer,E>
public final class IntVertexDijkstraShortestPath<E> extends BaseShortestPathAlgorithm<java.lang.Integer,E>
Dijkstra Shortest Path implementation specialized for graphs with integer vertices.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.
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Nested Class Summary
Nested Classes Modifier and Type Class Description private class
IntVertexDijkstraShortestPath.Algorithm
The actual implementation class.private class
IntVertexDijkstraShortestPath.ArrayBasedSingleSourcePathsImpl
private class
IntVertexDijkstraShortestPath.IdentifierMap
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>
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Field Summary
Fields Modifier and Type Field Description private java.util.function.Supplier<org.jheaps.AddressableHeap<java.lang.Double,java.lang.Integer>>
heapSupplier
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Fields 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
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Constructor Summary
Constructors Constructor Description IntVertexDijkstraShortestPath(Graph<java.lang.Integer,E> graph)
Constructs a new instance of the algorithm for a given graph.IntVertexDijkstraShortestPath(Graph<java.lang.Integer,E> graph, java.util.function.Supplier<org.jheaps.AddressableHeap<java.lang.Double,java.lang.Integer>> heapSupplier)
Constructs a new instance of the algorithm for a given graph.
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description static <E> GraphPath<java.lang.Integer,E>
findPathBetween(Graph<java.lang.Integer,E> graph, java.lang.Integer source, java.lang.Integer sink)
Find a path between two vertices.GraphPath<java.lang.Integer,E>
getPath(java.lang.Integer source, java.lang.Integer sink)
Get a shortest path from a source vertex to a sink vertex.ShortestPathAlgorithm.SingleSourcePaths<java.lang.Integer,E>
getPaths(java.lang.Integer source)
Compute all shortest paths starting from a single source vertex.-
Methods inherited from class org.jgrapht.alg.shortestpath.BaseShortestPathAlgorithm
createEmptyPath, getPathWeight
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Constructor Detail
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IntVertexDijkstraShortestPath
public IntVertexDijkstraShortestPath(Graph<java.lang.Integer,E> graph)
Constructs a new instance of the algorithm for a given graph.- Parameters:
graph
- the graph
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IntVertexDijkstraShortestPath
public IntVertexDijkstraShortestPath(Graph<java.lang.Integer,E> graph, java.util.function.Supplier<org.jheaps.AddressableHeap<java.lang.Double,java.lang.Integer>> heapSupplier)
Constructs a new instance of the algorithm for a given graph.- Parameters:
graph
- the graphheapSupplier
- supplier of the preferable heap implementation
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Method Detail
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findPathBetween
public static <E> GraphPath<java.lang.Integer,E> findPathBetween(Graph<java.lang.Integer,E> graph, java.lang.Integer source, java.lang.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
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getPath
public GraphPath<java.lang.Integer,E> getPath(java.lang.Integer source, java.lang.Integer sink)
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
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getPaths
public ShortestPathAlgorithm.SingleSourcePaths<java.lang.Integer,E> getPaths(java.lang.Integer 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(Integer, Integer)
for the same source but different sink vertex.- Specified by:
getPaths
in interfaceShortestPathAlgorithm<java.lang.Integer,E>
- Overrides:
getPaths
in classBaseShortestPathAlgorithm<java.lang.Integer,E>
- Parameters:
source
- the source vertex- Returns:
- the shortest paths
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