org.jgrapht.generate

Class RandomGraphGenerator.DefaultEdgeTopologyFactory<VV,EE>

java.lang.Object

org.jgrapht.generate.RandomGraphGenerator.DefaultEdgeTopologyFactory<VV,EE>

All Implemented Interfaces:

RandomGraphGenerator.EdgeTopologyFactory<VV,EE>

Enclosing class:

RandomGraphGenerator<V,E>

public class RandomGraphGenerator.DefaultEdgeTopologyFactory<VV,EE>
extends Object
implements RandomGraphGenerator.EdgeTopologyFactory<VV,EE>

Default implementation of the EdgeTopologyFactory interface. randomly chooses an edge and tries to add it. If the add fails from any reason (like: self edge / multiple edges in unpermitted graph type) it will just choose another and try again. Performance:

1. when the number of possible edges becomes slim , this class will have a very poor performance , cause it will not use gready methods to choose them. for example : In simple graph , if #V = N (#x = number Of x) and we want full mesh #edges= N*(N-1)/2 , the first added edges will do so quickly (O(1) , the last will take O(N^2). So , do not use it in this kind of graphs.
2. If the numberOfEdges is bigger than what the graph can add, there will be an infinite loop here. It is not tested.

Since:

Aug 6, 2005

Author:

Assaf

Constructor Summary

Constructors

Constructor and Description
RandomGraphGenerator.DefaultEdgeTopologyFactory()

Method Summary

Methods

Modifier and Type	Method and Description
void	createEdges(Graph<VV,EE> targetGraph, Map<Integer,VV> orderToVertexMap, int numberOfEdges, Random randomizer) Two different calls to the createEdges() with the same parameters must result in the generation of the same.
int	getMaxEdgesForVertexNum(Graph<VV,EE> targetGraph) Return max edges for that graph.
boolean	isNumberOfEdgesValid(Graph<VV,EE> targetGraph, int numberOfEdges) checks if the numOfEdges is smaller than the Max edges according to the following table:

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RandomGraphGenerator.DefaultEdgeTopologyFactory

public RandomGraphGenerator.DefaultEdgeTopologyFactory()

Method Detail

createEdges

public void createEdges(Graph<VV,EE> targetGraph,
               Map<Integer,VV> orderToVertexMap,
               int numberOfEdges,
               Random randomizer)

Description copied from interface: RandomGraphGenerator.EdgeTopologyFactory

Two different calls to the createEdges() with the same parameters must result in the generation of the same. But if the randomizer is different, it should, usually, create different edge topology.

Specified by:

createEdges in interface RandomGraphGenerator.EdgeTopologyFactory<VV,EE>

Parameters:

targetGraph - - guranteed to start with zero edges.

orderToVertexMap - - key=Integer of vertex order . between zero to numOfVertexes (exclusive). value = vertex from the graph. unique.

numberOfEdges - - to create in the graph

isNumberOfEdgesValid

public boolean isNumberOfEdgesValid(Graph<VV,EE> targetGraph,
                           int numberOfEdges)

checks if the numOfEdges is smaller than the Max edges according to the following table:

Graph Type	Directed / UnDirected	multiple edges	loops	Max Edges
SimpleGraph	UnDirected	-	-	N(N-1)/2
Multigraph	UnDirected	+	-	Infinite
Pseudograph	UnDirected	+	+	Infinite
SimpleDirectedGraph	Directed	-	-	N (N-1)
DefaultDirectedGraph	Directed	-	+	N*(N-1)+ N = N^2
DirectedMultigraph	Directed	+	+	Infinite

Specified by:

isNumberOfEdgesValid in interface RandomGraphGenerator.EdgeTopologyFactory<VV,EE>

Parameters:

targetGraph - guranteed to start with zero edges.

See Also:

RandomGraphGenerator.EdgeTopologyFactory.isNumberOfEdgesValid(Graph, int)

getMaxEdgesForVertexNum

public int getMaxEdgesForVertexNum(Graph<VV,EE> targetGraph)

Return max edges for that graph. If it is infinite return -1 instead.