/**
* 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.Set;
import org.junit.Test;
import org.neo4j.graphalgo.CostEvaluator;
import org.neo4j.graphalgo.impl.centrality.StressCentrality;
import org.neo4j.graphalgo.impl.shortestpath.SingleSourceShortestPath;
import org.neo4j.graphalgo.impl.shortestpath.SingleSourceShortestPathDijkstra;
import org.neo4j.graphdb.Direction;
import org.neo4j.graphdb.Node;
import org.neo4j.graphdb.Relationship;
import common.Neo4jAlgoTestCase;
public class StressCentralityTest 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 );
}
protected void assertCentrality( StressCentrality<Double> stressCentrality,
String nodeId, Double value )
{
assertTrue( stressCentrality.getCentrality( graph.getNode( nodeId ) )
.equals( value ) );
}
@Test
public void testBox()
{
graph.makeEdgeChain( "a,b,c,d,a" );
StressCentrality<Double> stressCentrality = new StressCentrality<Double>(
getSingleSourceShortestPath(), graph.getAllNodes() );
stressCentrality.calculate();
assertCentrality( stressCentrality, "a", 1.0 );
assertCentrality( stressCentrality, "b", 1.0 );
assertCentrality( stressCentrality, "c", 1.0 );
assertCentrality( stressCentrality, "d", 1.0 );
}
@Test
public void testPlusShape()
{
graph.makeEdgeChain( "a,b,c" );
graph.makeEdgeChain( "d,b,e" );
StressCentrality<Double> stressCentrality = new StressCentrality<Double>(
getSingleSourceShortestPath(), graph.getAllNodes() );
stressCentrality.calculate();
assertCentrality( stressCentrality, "a", 0.0 );
assertCentrality( stressCentrality, "b", 6.0 );
assertCentrality( stressCentrality, "c", 0.0 );
assertCentrality( stressCentrality, "d", 0.0 );
assertCentrality( stressCentrality, "e", 0.0 );
}
@Test
public void testChain()
{
graph.makeEdgeChain( "a,b,c,d,e" );
StressCentrality<Double> stressCentrality = new StressCentrality<Double>(
getSingleSourceShortestPath(), graph.getAllNodes() );
stressCentrality.calculate();
assertCentrality( stressCentrality, "a", 0.0 );
assertCentrality( stressCentrality, "b", 3.0 );
assertCentrality( stressCentrality, "c", 4.0 );
assertCentrality( stressCentrality, "d", 3.0 );
assertCentrality( stressCentrality, "e", 0.0 );
}
@Test
public void testStressUpdating()
{
graph.makeEdgeChain( "a,b,c,d,e,f" );
new StressTest( getSingleSourceShortestPath(), graph.getAllNodes() )
.test();
}
class StressTest extends StressCentrality<Double>
{
public StressTest(
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( "c" );
singleSourceShortestPath.reset();
singleSourceShortestPath.setStartNode( startNode );
processShortestPaths( startNode, singleSourceShortestPath );
Double adjustment = 0.5; // since direction is BOTH
assertCentrality( this, "a", 0.0 * adjustment );
assertCentrality( this, "b", 1.0 * adjustment );
assertCentrality( this, "c", 0.0 * adjustment );
assertCentrality( this, "d", 2.0 * adjustment );
assertCentrality( this, "e", 1.0 * adjustment );
assertCentrality( this, "f", 0.0 * adjustment );
}
}
}