/**
* Copyright (c) 2002-2011 "Neo Technology,"
* Network Engine for Objects in Lund AB [http://neotechnology.com]
*
* This file is part of Neo4j.
*
* Neo4j is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.neo4j.graphalgo.centrality;
import static org.junit.Assert.assertTrue;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.junit.Test;
import org.neo4j.graphalgo.CostEvaluator;
import org.neo4j.graphalgo.impl.centrality.BetweennessCentrality;
import org.neo4j.graphalgo.impl.shortestpath.SingleSourceShortestPath;
import org.neo4j.graphalgo.impl.shortestpath.SingleSourceShortestPathDijkstra;
import org.neo4j.graphalgo.impl.shortestpath.Util;
import org.neo4j.graphalgo.impl.shortestpath.Util.PathCounter;
import org.neo4j.graphdb.Direction;
import org.neo4j.graphdb.Node;
import org.neo4j.graphdb.Relationship;
import common.Neo4jAlgoTestCase;
public class BetweennessCentralityTest extends Neo4jAlgoTestCase
{
protected SingleSourceShortestPath<Double> getSingleSourceShortestPath()
{
return new SingleSourceShortestPathDijkstra<Double>( 0.0, null,
new CostEvaluator<Double>()
{
public Double getCost( Relationship relationship,
Direction direction )
{
return 1.0;
}
}, new org.neo4j.graphalgo.impl.util.DoubleAdder(),
new org.neo4j.graphalgo.impl.util.DoubleComparator(),
Direction.BOTH, MyRelTypes.R1, MyRelTypes.R2, MyRelTypes.R3 );
}
protected void assertCentrality(
BetweennessCentrality<Double> betweennessCentrality, String nodeId,
Double value )
{
assertTrue( betweennessCentrality
.getCentrality( graph.getNode( nodeId ) ).equals( value ) );
}
@Test
public void testBox()
{
graph.makeEdgeChain( "a,b,c,d,a" );
BetweennessCentrality<Double> betweennessCentrality = new BetweennessCentrality<Double>(
getSingleSourceShortestPath(), graph.getAllNodes() );
betweennessCentrality.calculate();
assertCentrality( betweennessCentrality, "a", 0.5 );
assertCentrality( betweennessCentrality, "b", 0.5 );
assertCentrality( betweennessCentrality, "c", 0.5 );
assertCentrality( betweennessCentrality, "d", 0.5 );
}
@Test
public void testPlusShape()
{
graph.makeEdgeChain( "a,b,c" );
graph.setCurrentRelType( MyRelTypes.R3 );
graph.makeEdgeChain( "d,b,e" );
BetweennessCentrality<Double> betweennessCentrality = new BetweennessCentrality<Double>(
getSingleSourceShortestPath(), graph.getAllNodes() );
betweennessCentrality.calculate();
assertCentrality( betweennessCentrality, "a", 0.0 );
assertCentrality( betweennessCentrality, "b", 6.0 );
assertCentrality( betweennessCentrality, "c", 0.0 );
assertCentrality( betweennessCentrality, "d", 0.0 );
assertCentrality( betweennessCentrality, "e", 0.0 );
}
@Test
public void testChain()
{
graph.makeEdgeChain( "a,b,c,d,e" );
BetweennessCentrality<Double> betweennessCentrality = new BetweennessCentrality<Double>(
getSingleSourceShortestPath(), graph.getAllNodes() );
betweennessCentrality.calculate();
assertCentrality( betweennessCentrality, "a", 0.0 );
assertCentrality( betweennessCentrality, "b", 3.0 );
assertCentrality( betweennessCentrality, "c", 4.0 );
assertCentrality( betweennessCentrality, "d", 3.0 );
assertCentrality( betweennessCentrality, "e", 0.0 );
}
@Test
public void testXlike()
{
graph.makeEdgeChain( "a,c,a");
graph.makeEdgeChain( "b,c,b");
graph.makeEdgeChain( "b,d,b");
graph.makeEdgeChain( "c,d,c");
graph.makeEdgeChain( "d,e,d");
graph.makeEdgeChain( "d,f,d");
BetweennessCentrality<Double> betweennessCentrality = new BetweennessCentrality<Double>(
getSingleSourceShortestPath(), graph.getAllNodes() );
betweennessCentrality.calculate();
assertCentrality( betweennessCentrality, "a", 0.0 );
assertCentrality( betweennessCentrality, "b", 0.0 );
assertCentrality( betweennessCentrality, "c", 4.0 );
assertCentrality( betweennessCentrality, "d", 7.0 );
assertCentrality( betweennessCentrality, "e", 0.0 );
assertCentrality( betweennessCentrality, "f", 0.0 );
}
@Test
public void testDependencyUpdating()
{
graph.makeEdgeChain( "a,b,d,e,f,h" );
graph.makeEdgeChain( "a,c,d" );
graph.makeEdgeChain( "e,g,h" );
new DependencyTest( getSingleSourceShortestPath(), graph.getAllNodes() )
.test();
}
class DependencyTest extends BetweennessCentrality<Double>
{
public DependencyTest(
SingleSourceShortestPath<Double> singleSourceShortestPath,
Set<Node> nodeSet )
{
super( singleSourceShortestPath, nodeSet );
}
public void test()
{
// avoid starting the real calculation by mistake
this.doneCalculation = true;
// set things up
Node startNode = graph.getNode( "a" );
singleSourceShortestPath.reset();
singleSourceShortestPath.setStartNode( startNode );
Map<Node,List<Relationship>> predecessors = singleSourceShortestPath
.getPredecessors();
Map<Node,List<Relationship>> successors = Util
.reversedPredecessors( predecessors );
PathCounter counter = new Util.PathCounter( predecessors );
// Recursively update the node dependencies
getAndUpdateNodeDependency( startNode, true, successors, counter,
new HashMap<Node,Double>() );
Double adjustment = 0.5; // since direction is BOTH
assertCentrality( this, "a", 0.0 * adjustment );
assertCentrality( this, "b", 2.5 * adjustment );
assertCentrality( this, "c", 2.5 * adjustment );
assertCentrality( this, "d", 4.0 * adjustment );
assertCentrality( this, "e", 3.0 * adjustment );
assertCentrality( this, "f", 0.5 * adjustment );
assertCentrality( this, "g", 0.5 * adjustment );
assertCentrality( this, "h", 0.0 * adjustment );
}
}
}