Module org.jgrapht.opt

Package org.jgrapht.opt.graph.sparse

Class SparseIntDirectedGraph

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.SparseIntDirectedGraph

All Implemented Interfaces:

Graph<Integer,Integer>

Direct Known Subclasses:

SparseIntDirectedWeightedGraph

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

A sparse directed 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 two boolean incidence matrix of the graph (rows are vertices and columns are edges) as Compressed Sparse Rows (CSR). Constant time source and target lookups are provided by storing the edge lists in arrays. 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

Modifier and Type	Field	Description
protected static final String	UNMODIFIABLE

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

specifics

Fields inherited from interface org.jgrapht.Graph

DEFAULT_EDGE_WEIGHT

Constructor Summary

Constructors

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

Field Details

UNMODIFIABLE

protected static final String UNMODIFIABLE

See Also:

• Constant Field Values

Constructor Details

SparseIntDirectedGraph

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

Create a new graph from an edge list.

Parameters:

numVertices - the number of vertices

edges - the edge list

SparseIntDirectedGraph

public SparseIntDirectedGraph(int numVertices,
 List<Pair<Integer,Integer>> edges,
 IncomingEdgesSupport incomingEdgesSupport)

Create a new graph from an edge list.

Parameters:

numVertices - the number of vertices

edges - the edge list

incomingEdgesSupport - whether to support incoming edges or not

SparseIntDirectedGraph

public SparseIntDirectedGraph(int numVertices,
 int numEdges,
 Supplier<Stream<Pair<Integer,Integer>>> edges,
 IncomingEdgesSupport incomingEdgesSupport)

Create a new graph from an edge stream.

Parameters:

numVertices - the number of vertices

numEdges - the number of edges

edges - the edge stream

incomingEdgesSupport - whether to support incoming edges or not