Module org.jgrapht.opt

Package org.jgrapht.opt.graph.sparse

Class SparseIntUndirectedGraph

java.lang.Object

org.jgrapht.graph.AbstractGraph<Integer,Integer>

org.jgrapht.opt.graph.sparse.specifics.AbstractSparseSpecificsGraph<org.jgrapht.opt.graph.sparse.specifics.SparseGraphSpecifics>

org.jgrapht.opt.graph.sparse.SparseIntUndirectedGraph

All Implemented Interfaces:

Graph<Integer,Integer>

Direct Known Subclasses:

SparseIntUndirectedWeightedGraph

public class SparseIntUndirectedGraph
extends org.jgrapht.opt.graph.sparse.specifics.AbstractSparseSpecificsGraph<org.jgrapht.opt.graph.sparse.specifics.SparseGraphSpecifics>

Sparse undirected graph.

Assuming the graph has $n$ vertices, the vertices are numbered from $0$ to $n-1$. Similarly, edges are numbered from $0$ to $m-1$ where $m$ is the total number of edges.

It stores the boolean incidence matrix of the graph (rows are vertices and columns are edges) as Compressed Sparse Rows (CSR). In order to also support constant time source and target lookups from an edge identifier we also store the transposed of the incidence matrix again in compressed sparse rows format. This is a classic format for write-once read-many use cases. Thus, the graph is unmodifiable.

The question of whether a sparse or dense representation is more appropriate is highly dependent on various factors such as the graph, the machine running the algorithm and the algorithm itself. Wilkinson defined a matrix as "sparse" if it has enough zeros that it pays to take advantage of them. For more details see

• Wilkinson, J. H. 1971. Linear algebra; part II: the algebraic eigenvalue problem. In Handbook for Automatic Computation, J. H. Wilkinson and C. Reinsch, Eds. Vol. 2. Springer-Verlag, Berlin, New York.

Additional information about sparse representations can be found in the wikipedia.

Author:

Dimitrios Michail

Field Summary

Fields inherited from class org.jgrapht.opt.graph.sparse.specifics.AbstractSparseSpecificsGraph

specifics, UNMODIFIABLE

Fields inherited from interface org.jgrapht.Graph

DEFAULT_EDGE_WEIGHT

Constructor Summary

Constructors

Constructor	Description
SparseIntUndirectedGraph(int numVertices, int numEdges, Supplier<Stream<Pair<Integer,Integer>>> edges)	Create a new graph from an edge stream
SparseIntUndirectedGraph(int numVertices, List<Pair<Integer,Integer>> edges)	Create a new graph from an edge list

Method Summary

Methods inherited from class org.jgrapht.opt.graph.sparse.specifics.AbstractSparseSpecificsGraph

addEdge, addEdge, addVertex, addVertex, containsEdge, containsVertex, degreeOf, edgeSet, edgesOf, getAllEdges, getEdge, getEdgeSource, getEdgeSupplier, getEdgeTarget, getEdgeWeight, getType, getVertexSupplier, incomingEdgesOf, inDegreeOf, outDegreeOf, outgoingEdgesOf, removeEdge, removeEdge, removeVertex, setEdgeWeight, vertexSet

Methods inherited from class org.jgrapht.graph.AbstractGraph

assertVertexExist, containsEdge, equals, hashCode, removeAllEdges, removeAllEdges, removeAllEdges, removeAllVertices, toString, toStringFromSets

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.jgrapht.Graph

iterables, setEdgeWeight

Constructor Details

SparseIntUndirectedGraph

public SparseIntUndirectedGraph(int numVertices,
 List<Pair<Integer,Integer>> edges)

Create a new graph from an edge list

Parameters:

numVertices - number of vertices

edges - edge list

SparseIntUndirectedGraph

public SparseIntUndirectedGraph(int numVertices,
 int numEdges,
 Supplier<Stream<Pair<Integer,Integer>>> edges)

Create a new graph from an edge stream

Parameters:

numVertices - number of vertices

numEdges - number of edges

edges - supplier of an edge stream