Package org.jgrapht.generate

Class BarabasiAlbertForestGenerator<V,E>

java.lang.Object

org.jgrapht.generate.BarabasiAlbertForestGenerator<V,E>

Type Parameters:

V - the graph vertex type

E - the graph edge type

All Implemented Interfaces:

GraphGenerator<V,E,V>

public class BarabasiAlbertForestGenerator<V,E>
extends Object
implements GraphGenerator<V,E,V>

Barabási-Albert growth and preferential attachment forest generator.

The general graph generator is described in the paper: A.-L. Barabási and R. Albert. Emergence of scaling in random networks. Science, 286:509-512, 1999.

The generator starts with a $t$ isolated nodes and grows the network by adding $n - t$ additional nodes. The additional nodes are added one by one and each of them is connected to one previously added node, where the probability of connecting to a node is proportional to its degree.

Note that this Barabàsi-Albert generator only works on undirected graphs. For a version that works on both directed and undirected graphs and generates only connected graphs see BarabasiAlbertGraphGenerator.

Author:

Alexandru Valeanu

Constructor Summary

Constructors

Constructor	Description
BarabasiAlbertForestGenerator(int t, int n)	Constructor
BarabasiAlbertForestGenerator(int t, int n, long seed)	Constructor
BarabasiAlbertForestGenerator(int t, int n, Random rng)	Constructor

Method Summary

Modifier and Type	Method	Description
void	generateGraph(Graph<V,E> target, Map<String,V> resultMap)	Generates an instance.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.jgrapht.generate.GraphGenerator

generateGraph

Constructor Detail

BarabasiAlbertForestGenerator

public BarabasiAlbertForestGenerator(int t,
                                     int n)

Constructor

Parameters:

t - number of trees

n - final number of nodes

Throws:

IllegalArgumentException - in case of invalid parameters

BarabasiAlbertForestGenerator

public BarabasiAlbertForestGenerator(int t,
                                     int n,
                                     long seed)

Constructor

Parameters:

t - number of trees

n - final number of nodes

seed - seed for the random number generator

Throws:

IllegalArgumentException - in case of invalid parameters

BarabasiAlbertForestGenerator

public BarabasiAlbertForestGenerator(int t,
                                     int n,
                                     Random rng)

Constructor

Parameters:

t - number of trees

n - final number of nodes

rng - the random number generator to use

Throws:

IllegalArgumentException - in case of invalid parameters

Method Detail

generateGraph

public void generateGraph(Graph<V,E> target,
                          Map<String,V> resultMap)

Generates an instance.

Note: An exception will be thrown if the target graph is not empty (i.e. contains at least one vertex)

Specified by:

generateGraph in interface GraphGenerator<V,E,V>

Parameters:

target - the target graph

resultMap - not used by this generator, can be null

Throws:

NullPointerException - if target is null

IllegalArgumentException - if target is not undirected

IllegalArgumentException - if target is not empty