org.jgrapht.demo.PerformanceDemo Maven / Gradle / Ivy

Go to download
/* ==========================================
 * JGraphT : a free Java graph-theory library
 * ==========================================
 *
 * Project Info:  http://jgrapht.sourceforge.net/
 * Project Creator:  Barak Naveh (http://sourceforge.net/users/barak_naveh)
 *
 * (C) Copyright 2003-2008, by Barak Naveh and Contributors.
 *
 * This program and the accompanying materials are dual-licensed under
 * either
 *
 * (a) the terms of the GNU Lesser General Public License version 2.1
 * as published by the Free Software Foundation, or (at your option) any
 * later version.
 *
 * or (per the licensee's choosing)
 *
 * (b) the terms of the Eclipse Public License v1.0 as published by
 * the Eclipse Foundation.
 */
/* --------------------
 * PerformanceDemo.java
 * --------------------
 * (C) Copyright 2003-2008, by Barak Naveh and Contributors.
 *
 * Original Author:  Barak Naveh
 * Contributor(s):   -
 *
 * $Id$
 *
 * Changes
 * -------
 * 10-Aug-2003 : Initial revision (BN);
 *
 */
package org.jgrapht.demo;

import java.io.*;

import java.util.*;

import org.jgrapht.*;
import org.jgrapht.graph.*;
import org.jgrapht.traverse.*;


/**
 * A simple demo to test memory and CPU consumption on a graph with 3 million
 * elements.
 *
 * NOTE: To run this demo you may need to increase the JVM max mem size. In
 * Sun's JVM it is done using the "-Xmx" switch. Specify "-Xmx300M" to set it to
 * 300MB.
 *
 * WARNING: Don't run this demo as-is on machines with less than 512MB
 * memory. Your machine will start paging severely. You need to first modify it
 * to have fewer graph elements. This is easily done by changing the loop
 * counters below.
 *
 * @author Barak Naveh
 * @since Aug 10, 2003
 */
public final class PerformanceDemo
{
    /**
     * The starting point for the demo.
     *
     * @param args ignored.
     */
    public static void main(String [] args)
    {
        long time = System.currentTimeMillis();

        reportPerformanceFor("starting at", time);

        Graph g =
            new Pseudograph(DefaultEdge.class);
        Object prev;
        Object curr;

        curr = prev = new Object();
        g.addVertex(prev);

        int numVertices = 10000;
        int numEdgesPerVertex = 200;
        int numElements = numVertices * (1 + numEdgesPerVertex);

        System.out.println(
            "\n" + "allocating graph with " + numElements
            + " elements (may take a few tens of seconds)...");

        for (int i = 0; i < numVertices; i++) {
            curr = new Object();
            g.addVertex(curr);

            for (int j = 0; j < numEdgesPerVertex; j++) {
                g.addEdge(prev, curr);
            }

            prev = curr;
        }

        reportPerformanceFor("graph allocation", time);

        time = System.currentTimeMillis();

        for (
            Iterator