- Type Parameters:
V
- the graph vertex typeE
- the graph edge type
- All Implemented Interfaces:
GraphGenerator<V,E,V>
public class BarabasiAlbertForestGenerator<V,E> extends java.lang.Object implements GraphGenerator<V,E,V>
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)
ConstructorBarabasiAlbertForestGenerator(int t, int n, long seed)
ConstructorBarabasiAlbertForestGenerator(int t, int n, java.util.Random rng)
Constructor -
Method Summary
Modifier and Type Method Description void
generateGraph(Graph<V,E> target, java.util.Map<java.lang.String,V> resultMap)
Generates an instance.
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Constructor Details
-
BarabasiAlbertForestGenerator
public BarabasiAlbertForestGenerator(int t, int n)Constructor- Parameters:
t
- number of treesn
- final number of nodes- Throws:
java.lang.IllegalArgumentException
- in case of invalid parameters
-
BarabasiAlbertForestGenerator
public BarabasiAlbertForestGenerator(int t, int n, long seed)Constructor- Parameters:
t
- number of treesn
- final number of nodesseed
- seed for the random number generator- Throws:
java.lang.IllegalArgumentException
- in case of invalid parameters
-
BarabasiAlbertForestGenerator
public BarabasiAlbertForestGenerator(int t, int n, java.util.Random rng)Constructor- Parameters:
t
- number of treesn
- final number of nodesrng
- the random number generator to use- Throws:
java.lang.IllegalArgumentException
- in case of invalid parameters
-
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Method Details
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generateGraph
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 interfaceGraphGenerator<V,E,V>
- Parameters:
target
- the target graphresultMap
- not used by this generator, can be null- Throws:
java.lang.NullPointerException
- iftarget
isnull
java.lang.IllegalArgumentException
- iftarget
is not undirectedjava.lang.IllegalArgumentException
- iftarget
is not empty
-