Initial opendaylight infrastructure commit!!

[controller.git] / third-party / net.sf.jung2 / src / main / java / edu / uci / ics / jung / algorithms / generators / random / ErdosRenyiGenerator.java

diff --git a/third-party/net.sf.jung2/src/main/java/edu/uci/ics/jung/algorithms/generators/random/ErdosRenyiGenerator.java b/third-party/net.sf.jung2/src/main/java/edu/uci/ics/jung/algorithms/generators/random/ErdosRenyiGenerator.java
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+++ b/third-party/net.sf.jung2/src/main/java/edu/uci/ics/jung/algorithms/generators/random/ErdosRenyiGenerator.java
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+/*
+* Copyright (c) 2003, the JUNG Project and the Regents of the University
+* of California
+* All rights reserved.
+*
+* This software is open-source under the BSD license; see either
+* "license.txt" or
+* http://jung.sourceforge.net/license.txt for a description.
+*/
+package edu.uci.ics.jung.algorithms.generators.random;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+
+import org.apache.commons.collections15.Factory;
+
+import edu.uci.ics.jung.algorithms.generators.GraphGenerator;
+import edu.uci.ics.jung.graph.Graph;
+import edu.uci.ics.jung.graph.UndirectedGraph;
+
+/**
+ * Generates a random graph using the Erdos-Renyi binomial model
+ * (each pair of vertices is connected with probability p).
+ * 
+ *  @author William Giordano, Scott White, Joshua O'Madadhain
+ */
+public class ErdosRenyiGenerator<V,E> implements GraphGenerator<V,E> {
+    private int mNumVertices;
+    private double mEdgeConnectionProbability;
+    private Random mRandom;
+    Factory<UndirectedGraph<V,E>> graphFactory;
+    Factory<V> vertexFactory;
+    Factory<E> edgeFactory;
+
+    /**
+     *
+     * @param numVertices number of vertices graph should have
+     * @param p Connection's probability between 2 vertices
+     */
+       public ErdosRenyiGenerator(Factory<UndirectedGraph<V,E>> graphFactory,
+                       Factory<V> vertexFactory, Factory<E> edgeFactory,
+                       int numVertices,double p)
+    {
+        if (numVertices <= 0) {
+            throw new IllegalArgumentException("A positive # of vertices must be specified.");
+        }
+        mNumVertices = numVertices;
+        if (p < 0 || p > 1) {
+            throw new IllegalArgumentException("p must be between 0 and 1.");
+        }
+        this.graphFactory = graphFactory;
+        this.vertexFactory = vertexFactory;
+        this.edgeFactory = edgeFactory;
+        mEdgeConnectionProbability = p;
+        mRandom = new Random();
+       }
+
+    /**
+     * Returns a graph in which each pair of vertices is connected by 
+     * an undirected edge with the probability specified by the constructor.
+     */
+       public Graph<V,E> create() {
+        UndirectedGraph<V,E> g = graphFactory.create();
+        for(int i=0; i<mNumVertices; i++) {
+               g.addVertex(vertexFactory.create());
+        }
+        List<V> list = new ArrayList<V>(g.getVertices());
+
+               for (int i = 0; i < mNumVertices-1; i++) {
+            V v_i = list.get(i);
+                       for (int j = i+1; j < mNumVertices; j++) {
+                V v_j = list.get(j);
+                               if (mRandom.nextDouble() < mEdgeConnectionProbability) {
+                                       g.addEdge(edgeFactory.create(), v_i, v_j);
+                               }
+                       }
+               }
+        return g;
+    }
+
+    /**
+     * Sets the seed of the internal random number generator to {@code seed}.
+     * Enables consistent behavior.
+     */
+    public void setSeed(long seed) {
+        mRandom.setSeed(seed);
+    }
+}
+
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