| Line | Hits | Source |
|---|---|---|
| 1 | /* | |
| 2 | * Copyright (c) 2003, the JUNG Project and the Regents of the University | |
| 3 | * of California | |
| 4 | * All rights reserved. | |
| 5 | * | |
| 6 | * This software is open-source under the BSD license; see either | |
| 7 | * "license.txt" or | |
| 8 | * http://jung.sourceforge.net/license.txt for a description. | |
| 9 | */ | |
| 10 | package edu.uci.ics.jung.random.generators; | |
| 11 | ||
| 12 | import java.util.Random; | |
| 13 | ||
| 14 | import edu.uci.ics.jung.graph.ArchetypeGraph; | |
| 15 | import edu.uci.ics.jung.graph.UndirectedGraph; | |
| 16 | import edu.uci.ics.jung.graph.Vertex; | |
| 17 | import edu.uci.ics.jung.graph.impl.UndirectedSparseEdge; | |
| 18 | import edu.uci.ics.jung.graph.impl.UndirectedSparseGraph; | |
| 19 | import edu.uci.ics.jung.utils.GraphUtils; | |
| 20 | ||
| 21 | /** | |
| 22 | * Random Generator of Erdos-Renyi "binomial model" | |
| 23 | * @author William Giordano, Scott White, Joshua O'Madadhain | |
| 24 | */ | |
| 25 | public class ErdosRenyiGenerator implements GraphGenerator | |
| 26 | { | |
| 27 | private int mNumVertices; | |
| 28 | private double mEdgeConnectionProbability; | |
| 29 | private Random mRandom; | |
| 30 | ||
| 31 | /** | |
| 32 | * | |
| 33 | * @param numVertices number of vertices graph should have | |
| 34 | * @param p Connection's probability between 2 vertices | |
| 35 | */ | |
| 36 | public ErdosRenyiGenerator(int numVertices,double p) | |
| 37 | 20 | { |
| 38 | 20 | if (numVertices <= 0) { |
| 39 | 0 | throw new IllegalArgumentException("A positive # of vertices must be specified."); |
| 40 | } | |
| 41 | 20 | mNumVertices = numVertices; |
| 42 | 20 | if (p < 0 || p > 1) { |
| 43 | 0 | throw new IllegalArgumentException("p must be between 0 and 1."); |
| 44 | } | |
| 45 | 20 | mEdgeConnectionProbability = p; |
| 46 | 20 | mRandom = new Random(); |
| 47 | 20 | } |
| 48 | ||
| 49 | /** | |
| 50 | * Returns a graph in which each pair of vertices is connected by | |
| 51 | * an undirected edge with the probability specified by the constructor. | |
| 52 | */ | |
| 53 | public ArchetypeGraph generateGraph() { | |
| 54 | 20 | UndirectedGraph g = new UndirectedSparseGraph(); |
| 55 | 20 | GraphUtils.addVertices(g,mNumVertices); |
| 56 | 20 | Object[] v_array = g.getVertices().toArray(); |
| 57 | ||
| 58 | 2000 | for (int i = 0; i < mNumVertices-1; i++) |
| 59 | { | |
| 60 | 1980 | Vertex v_i = (Vertex) v_array[i]; |
| 61 | 100980 | for (int j = i+1; j < mNumVertices; j++) |
| 62 | { | |
| 63 | 99000 | Vertex v_j = (Vertex) v_array[j]; |
| 64 | 99000 | if (mRandom.nextDouble() < mEdgeConnectionProbability) |
| 65 | 10860 | g.addEdge(new UndirectedSparseEdge(v_i, v_j)); |
| 66 | } | |
| 67 | } | |
| 68 | 20 | return g; |
| 69 | } | |
| 70 | ||
| 71 | public void setSeed(long seed) { | |
| 72 | 20 | mRandom.setSeed(seed); |
| 73 | 20 | } |
| 74 | } | |
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this report was generated by version 1.0.5 of jcoverage. |
copyright © 2003, jcoverage ltd. all rights reserved. |