/* ==========================================
* 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.
*/
/* -------------------
* DirectedAcyclicGraphTest.java
* -------------------
* (C) Copyright 2008-2008, by Peter Giles and Contributors.
*
* Original Author: Peter Giles
* Contributor(s): -
*
* $Id$
*
* Changes
* -------
* 17-Mar-2008 : Initial revision (PG);
*
*/
package org.jgrapht.experimental.dag;
import java.util.*;
import junit.framework.*;
import org.jgrapht.*;
import org.jgrapht.alg.*;
import org.jgrapht.experimental.dag.DirectedAcyclicGraph.CycleFoundException;
import org.jgrapht.generate.*;
import org.jgrapht.graph.*;
import org.jgrapht.traverse.*;
/**
* Unit tests for the DirectedAcyclicGraph, a dynamic DAG implementation.
*
* @author gilesp@u.washington.edu
*/
public class DirectedAcyclicGraphTest
extends TestCase
{
//~ Instance fields --------------------------------------------------------
private RandomGraphGenerator<Long, DefaultEdge> randomGraphGenerator = null;
private Graph<Long, DefaultEdge> sourceGraph = null;
//~ Methods ----------------------------------------------------------------
@Override protected void setUp()
throws Exception
{
super.setUp();
setUpWithSeed(100, 5000, 2);
}
private void setUpWithSeed(int vertices, int edges, long seed)
{
randomGraphGenerator =
new RepeatableRandomGraphGenerator<Long, DefaultEdge>(
vertices,
edges,
seed);
sourceGraph =
new SimpleDirectedGraph<Long, DefaultEdge>(DefaultEdge.class);
randomGraphGenerator.generateGraph(
sourceGraph,
new LongVertexFactory(),
null);
}
/**
* Tests the cycle detection capabilities of DirectedAcyclicGraph by
* building a parallel SimpleDirectedGraph and using a CycleDetector to
* check for cycles, and comparing the results.
*/
public void testCycleDetectionInRandomGraphBuild()
{
for (int i = 0; i < 50; i++) { // test with 50 random graph
// configurations
setUpWithSeed(20, 200, i);
DirectedAcyclicGraph<Long, DefaultEdge> dag =
new DirectedAcyclicGraph<Long, DefaultEdge>(DefaultEdge.class);
SimpleDirectedGraph<Long, DefaultEdge> compareGraph =
new SimpleDirectedGraph<Long, DefaultEdge>(DefaultEdge.class);
for (Long vertex : sourceGraph.vertexSet()) {
dag.addVertex(vertex);
compareGraph.addVertex(vertex);
}
for (DefaultEdge edge : sourceGraph.edgeSet()) {
Long edgeSource = sourceGraph.getEdgeSource(edge);
Long edgeTarget = sourceGraph.getEdgeTarget(edge);
boolean dagRejectedEdge = false;
try {
dag.addDagEdge(edgeSource, edgeTarget);
} catch (DirectedAcyclicGraph.CycleFoundException e) {
// okay, it did't add that edge
dagRejectedEdge = true;
}
DefaultEdge compareEdge =
compareGraph.addEdge(edgeSource, edgeTarget);
CycleDetector<Long, DefaultEdge> cycleDetector =
new CycleDetector<Long, DefaultEdge>(compareGraph);
boolean cycleDetected = cycleDetector.detectCycles();
assertTrue(dagRejectedEdge == cycleDetected);
if (cycleDetected) {
// remove the edge from the compareGraph so the graphs
// remain in sync
compareGraph.removeEdge(compareEdge);
}
}
// after all this, our graphs must be equal
assertEquals(compareGraph.vertexSet(), dag.vertexSet());
// for some reason comparing vertex sets doesn't work, so doing it
// the hard way:
for (Long sourceVertex : compareGraph.vertexSet()) {
for (
DefaultEdge outgoingEdge
: compareGraph.outgoingEdgesOf(sourceVertex))
{
Long targetVertex =
compareGraph.getEdgeTarget(outgoingEdge);
assertTrue(dag.containsEdge(sourceVertex, targetVertex));
}
}
}
}
/**
* trivial test of topological order using a linear graph
*/
public void testTopoIterationOrderLinearGraph()
{
DirectedAcyclicGraph<Long, DefaultEdge> dag =
new DirectedAcyclicGraph<Long, DefaultEdge>(DefaultEdge.class);
LinearGraphGenerator<Long, DefaultEdge> graphGen =
new LinearGraphGenerator<Long, DefaultEdge>(100);
graphGen.generateGraph(dag, new LongVertexFactory(), null);
Iterator<Long> internalTopoIter = dag.iterator();
TopologicalOrderIterator<Long, DefaultEdge> comparTopoIter =
new TopologicalOrderIterator<Long, DefaultEdge>(dag);
while (comparTopoIter.hasNext()) {
Long compareNext = comparTopoIter.next();
Long myNext = null;
if (internalTopoIter.hasNext()) {
myNext = internalTopoIter.next();
}
assertSame(compareNext, myNext);
assertEquals(comparTopoIter.hasNext(), internalTopoIter.hasNext());
}
}
/**
* more rigorous test of topological iteration order, by assuring that each
* visited vertex adheres to the definition of topological order, that is
* that it doesn't have a path leading to any of its predecessors.
*/
public void testTopoIterationOrderComplexGraph()
{
for (int seed = 0; seed < 20; seed++) {
DirectedAcyclicGraph<Long, DefaultEdge> dag =
new DirectedAcyclicGraph<Long, DefaultEdge>(DefaultEdge.class);
RepeatableRandomGraphGenerator<Long, DefaultEdge> graphGen =
new RepeatableRandomGraphGenerator<Long, DefaultEdge>(
100,
500,
seed);
graphGen.generateGraph(dag, new LongVertexFactory(), null);
ConnectivityInspector<Long, DefaultEdge> connectivityInspector =
new ConnectivityInspector<Long, DefaultEdge>(dag);
Iterator<Long> internalTopoIter = dag.iterator();
List<Long> previousVertices = new ArrayList<Long>();
while (internalTopoIter.hasNext()) {
Long vertex = internalTopoIter.next();
for (Long previousVertex : previousVertices) {
connectivityInspector.pathExists(vertex, previousVertex);
}
previousVertices.add(vertex);
}
}
}
public void testIterationBehaviors()
{
int vertexCount = 100;
DirectedAcyclicGraph<Long, DefaultEdge> dag =
new DirectedAcyclicGraph<Long, DefaultEdge>(DefaultEdge.class);
RepeatableRandomGraphGenerator<Long, DefaultEdge> graphGen =
new RepeatableRandomGraphGenerator<Long, DefaultEdge>(
vertexCount,
500,
2);
graphGen.generateGraph(dag, new LongVertexFactory(), null);
Iterator<Long> dagIter = dag.iterator();
// Scroll through all the elements, then make sure things happen as
// should when an iterator is all used up
for (int i = 0; i < vertexCount; i++) {
assertTrue(dagIter.hasNext());
dagIter.next();
}
assertFalse(dagIter.hasNext());
try {
dagIter.next();
fail();
} catch (NoSuchElementException e) {
// good, we already looked at all of the elements
}
assertFalse(dagIter.hasNext());
dagIter = dag.iterator(); // replace dagIter;
assertNotNull(dagIter.next()); // make sure it works on first element
// even if hasNext() wasn't called
// Test that ConcurrentModificationExceptionS happen as they should when
// the topology is modified during iteration
// remove a random vertex
dag.removeVertex(dag.vertexSet().iterator().next());
// now we expect exceptions since the topological order has been
// modified (albeit trivially)
try {
dagIter.next();
fail(); // fail, no exception was thrown
} catch (ConcurrentModificationException e) {
// good, this is expected
}
try {
dagIter.hasNext();
fail(); // fail, no exception was thrown
} catch (ConcurrentModificationException e) {
// good, this is expected
}
try {
dagIter.remove();
fail(); // fail, no exception was thrown
} catch (ConcurrentModificationException e) {
// good, this is expected
}
// TODO: further iterator tests
}
// Performance tests have underscores in the names so that they
// they are only run explicitly (not automatically as part of
// default JUnit runs).
/**
* A somewhat frivolous test of the performance difference between doing a
* full cycle detection (non-dynamic algorithm) for each edge added versus
* the dynamic algorithm used by DirectedAcyclicGraph.
*/
public void _testPerformanceVersusStaticChecking()
{
int trialsPerConfiguration = 10;
int maxVertices = 1024;
int maxConnectednessFactor = 4;
for (
int numVertices = 1024;
numVertices <= maxVertices;
numVertices *= 2)
{
for (
int connectednessFactor = 1;
(connectednessFactor <= maxConnectednessFactor)
&& (connectednessFactor < (numVertices - 1));
connectednessFactor *= 2)
{
long dynamicDagTime = 0;
long staticDagTime = 0;
for (int seed = 0; seed < trialsPerConfiguration; seed++) { // test with random graph configurations
setUpWithSeed(
numVertices,
numVertices * connectednessFactor,
seed);
DirectedAcyclicGraph<Long, DefaultEdge> dag =
new DirectedAcyclicGraph<Long, DefaultEdge>(
DefaultEdge.class);
long dynamicOpStart = System.nanoTime();
for (Long vertex : sourceGraph.vertexSet()) {
dag.addVertex(vertex);
}
for (DefaultEdge edge : sourceGraph.edgeSet()) {
Long edgeSource = sourceGraph.getEdgeSource(edge);
Long edgeTarget = sourceGraph.getEdgeTarget(edge);
dag.addEdge(edgeSource, edgeTarget);
}
dynamicDagTime += System.nanoTime() - dynamicOpStart;
SimpleDirectedGraph<Long, DefaultEdge> compareGraph =
new SimpleDirectedGraph<Long, DefaultEdge>(
DefaultEdge.class);
long staticOpStart = System.nanoTime();
for (Long vertex : sourceGraph.vertexSet()) {
compareGraph.addVertex(vertex);
}
for (DefaultEdge edge : sourceGraph.edgeSet()) {
Long edgeSource = sourceGraph.getEdgeSource(edge);
Long edgeTarget = sourceGraph.getEdgeTarget(edge);
DefaultEdge compareEdge =
compareGraph.addEdge(edgeSource, edgeTarget);
CycleDetector<Long, DefaultEdge> cycleDetector =
new CycleDetector<Long, DefaultEdge>(compareGraph);
boolean cycleDetected = cycleDetector.detectCycles();
if (cycleDetected) {
// remove the edge from the compareGraph
compareGraph.removeEdge(compareEdge);
}
}
staticDagTime += System.nanoTime() - staticOpStart;
}
System.out.println(
"vertices = " + numVertices + " connectednessFactor = "
+ connectednessFactor + " trialsPerConfiguration = "
+ trialsPerConfiguration);
System.out.println(
"total static DAG time = " + staticDagTime + " ns");
System.out.println(
"total dynamic DAG time = " + dynamicDagTime + " ns");
System.out.println();
}
}
}
/**
* A somewhat frivolous test of the performance difference between doing a
* full cycle detection (non-dynamic algorithm) for each edge added versus
* the dynamic algorithm used by DirectedAcyclicGraph.
*/
public void _testVisitedImplementationPerformance()
{
int trialsPerConfiguration = 10;
int maxVertices = 1024;
int maxConnectednessFactor = 4;
for (
int numVertices = 64;
numVertices <= maxVertices;
numVertices *= 2)
{
for (
int connectednessFactor = 1;
(connectednessFactor <= maxConnectednessFactor)
&& (connectednessFactor < (numVertices - 1));
connectednessFactor *= 2)
{
long arrayDagTime = 0;
long arrayListDagTime = 0;
long hashSetDagTime = 0;
long bitSetDagTime = 0;
for (int seed = 0; seed < trialsPerConfiguration; seed++) { // test with random graph configurations
setUpWithSeed(
numVertices,
numVertices * connectednessFactor,
seed);
DirectedAcyclicGraph<Long, DefaultEdge> arrayDag =
new DirectedAcyclicGraph<Long, DefaultEdge>(
DefaultEdge.class,
new DirectedAcyclicGraph.VisitedArrayImpl(),
null);
DirectedAcyclicGraph<Long, DefaultEdge> arrayListDag =
new DirectedAcyclicGraph<Long, DefaultEdge>(
DefaultEdge.class,
new DirectedAcyclicGraph.VisitedArrayListImpl(),
null);
DirectedAcyclicGraph<Long, DefaultEdge> hashSetDag =
new DirectedAcyclicGraph<Long, DefaultEdge>(
DefaultEdge.class,
new DirectedAcyclicGraph.VisitedHashSetImpl(),
null);
DirectedAcyclicGraph<Long, DefaultEdge> bitSetDag =
new DirectedAcyclicGraph<Long, DefaultEdge>(
DefaultEdge.class,
new DirectedAcyclicGraph.VisitedBitSetImpl(),
null);
long arrayStart = System.nanoTime();
for (Long vertex : sourceGraph.vertexSet()) {
arrayDag.addVertex(vertex);
}
for (DefaultEdge edge : sourceGraph.edgeSet()) {
Long edgeSource = sourceGraph.getEdgeSource(edge);
Long edgeTarget = sourceGraph.getEdgeTarget(edge);
try {
arrayDag.addDagEdge(edgeSource, edgeTarget);
} catch (DirectedAcyclicGraph.CycleFoundException e) {
// okay
}
}
arrayDagTime += System.nanoTime() - arrayStart;
long arrayListStart = System.nanoTime();
for (Long vertex : sourceGraph.vertexSet()) {
arrayListDag.addVertex(vertex);
}
for (DefaultEdge edge : sourceGraph.edgeSet()) {
Long edgeSource = sourceGraph.getEdgeSource(edge);
Long edgeTarget = sourceGraph.getEdgeTarget(edge);
try {
arrayListDag.addDagEdge(edgeSource, edgeTarget);
} catch (DirectedAcyclicGraph.CycleFoundException e) {
// okay
}
}
arrayListDagTime += System.nanoTime() - arrayListStart;
long hashSetStart = System.nanoTime();
for (Long vertex : sourceGraph.vertexSet()) {
hashSetDag.addVertex(vertex);
}
for (DefaultEdge edge : sourceGraph.edgeSet()) {
Long edgeSource = sourceGraph.getEdgeSource(edge);
Long edgeTarget = sourceGraph.getEdgeTarget(edge);
try {
hashSetDag.addDagEdge(edgeSource, edgeTarget);
} catch (DirectedAcyclicGraph.CycleFoundException e) {
// okay
}
}
hashSetDagTime += System.nanoTime() - hashSetStart;
long bitSetStart = System.nanoTime();
for (Long vertex : sourceGraph.vertexSet()) {
bitSetDag.addVertex(vertex);
}
for (DefaultEdge edge : sourceGraph.edgeSet()) {
Long edgeSource = sourceGraph.getEdgeSource(edge);
Long edgeTarget = sourceGraph.getEdgeTarget(edge);
try {
bitSetDag.addDagEdge(edgeSource, edgeTarget);
} catch (DirectedAcyclicGraph.CycleFoundException e) {
// okay
}
}
bitSetDagTime += System.nanoTime() - bitSetStart;
}
System.out.println(
"vertices = " + numVertices + " connectednessFactor = "
+ connectednessFactor + " trialsPerConfiguration = "
+ trialsPerConfiguration);
System.out.println(
"total array time = " + arrayDagTime + " ns");
System.out.println(
"total ArrayList time = " + arrayListDagTime + " ns");
System.out.println(
"total HashSet time = " + hashSetDagTime + " ns");
System.out.println(
"total BitSet time = " + bitSetDagTime + " ns");
System.out.println();
}
}
}
public void testWhenVertexIsNotInGraph_Then_ThowException() {
DirectedAcyclicGraph<Long, DefaultEdge> dag =
new DirectedAcyclicGraph<Long, DefaultEdge>(DefaultEdge.class);
try {
dag.addDagEdge(1l, 2l);
} catch(IllegalArgumentException e) {
return;
} catch (CycleFoundException e) {
e.printStackTrace();
fail("Unexpected 'CycleFoundException' catched");
}
fail("No exception 'IllegalArgumentException' catched");
}
//~ Inner Classes ----------------------------------------------------------
private static class LongVertexFactory
implements VertexFactory<Long>
{
private long nextVertex = 0;
public Long createVertex()
{
return nextVertex++;
}
}
// it is nice for tests to be easily repeatable, so we use a graph generator
// that we can seed for specific configurations
private static class RepeatableRandomGraphGenerator<V, E>
extends RandomGraphGenerator<V, E>
{
public RepeatableRandomGraphGenerator(
int vertices,
int edges,
long seed)
{
super(vertices, edges);
randomizer = new Random(seed);
}
@Override public void generateGraph(
Graph<V, E> graph,
VertexFactory<V> vertexFactory,
Map<String, V> namedVerticesMap)
{
List<V> vertices = new ArrayList<V>(numOfVertexes);
Set<Integer> edgeGeneratorIds = new HashSet<Integer>();
for (int i = 0; i < numOfVertexes; i++) {
V vertex = vertexFactory.createVertex();
vertices.add(vertex);
graph.addVertex(vertex);
}
for (int i = 0; i < numOfEdges; i++) {
Integer edgeGeneratorId;
do {
edgeGeneratorId =
randomizer.nextInt(numOfVertexes * (numOfVertexes - 1));
} while (edgeGeneratorIds.contains(edgeGeneratorId));
int fromVertexId = edgeGeneratorId / numOfVertexes;
int toVertexId = edgeGeneratorId % (numOfVertexes - 1);
if (toVertexId >= fromVertexId) {
++toVertexId;
}
try {
graph.addEdge(
vertices.get(fromVertexId),
vertices.get(toVertexId));
} catch (IllegalArgumentException e) {
// okay, that's fine; omit cycle
}
}
}
}
}
// End DirectedAcyclicGraphTest.java