/* ==========================================
* 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.
*
* <p>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.</p>
*
* <p>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.</p>
*
* @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<Object, DefaultEdge> g =
new Pseudograph<Object, DefaultEdge>(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<Object> i =
new BreadthFirstIterator<Object, DefaultEdge>(g);
i.hasNext();)
{
i.next();
}
reportPerformanceFor("breadth traversal", time);
time = System.currentTimeMillis();
for (
Iterator<Object> i = new DepthFirstIterator<Object, DefaultEdge>(g);
i.hasNext();)
{
i.next();
}
reportPerformanceFor("depth traversal", time);
System.out.println(
"\n"
+ "Paused: graph is still in memory (to check mem consumption).");
System.out.print("press enter to free memory and finish...");
try {
System.in.read();
} catch (IOException e) {
e.printStackTrace();
}
System.out.println("done.");
}
private static void reportPerformanceFor(String msg, long refTime)
{
double time = (System.currentTimeMillis() - refTime) / 1000.0;
double mem = usedMemory()
/ (1024.0 * 1024.0);
mem = Math.round(mem * 100) / 100.0;
System.out.println(msg + " (" + time + " sec, " + mem + "MB)");
}
private static long usedMemory()
{
Runtime rt = Runtime.getRuntime();
return rt.totalMemory() - rt.freeMemory();
}
}
// End PerformanceDemo.java