/*
* Copyright 2008 Network Engine for Objects in Lund AB [neotechnology.com]
*
* This program 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.shortestPath;
import org.neo4j.graphalgo.shortestpath.Dijkstra;
import org.neo4j.graphalgo.testUtil.NeoAlgoTestCase;
import org.neo4j.graphalgo.testUtil.SimpleGraphBuilder;
import org.neo4j.graphdb.Direction;
public class DijkstraTest extends NeoAlgoTestCase
{
public DijkstraTest( String arg0 )
{
super( arg0 );
}
protected Dijkstra<Double> getDijkstra( SimpleGraphBuilder graph,
Double startCost, String startNode, String endNode )
{
return new Dijkstra<Double>( startCost, graph.getNode( startNode ),
graph.getNode( endNode ),
new org.neo4j.graphalgo.shortestpath.std.DoubleEvaluator( "cost" ),
new org.neo4j.graphalgo.shortestpath.std.DoubleAdder(),
new org.neo4j.graphalgo.shortestpath.std.DoubleComparator(),
Direction.BOTH, MyRelTypes.R1 );
}
/**
* Test case for just a single node (path length zero)
*/
public void testDijkstraMinimal()
{
graph.makeNode( "lonely" );
Dijkstra<Double> dijkstra = getDijkstra( graph, 0.0, "lonely", "lonely" );
assertTrue( dijkstra.getCost() == 0.0 );
assertTrue( dijkstra.getPathAsNodes().size() == 1 );
dijkstra = getDijkstra( graph, 3.0, "lonely", "lonely" );
assertTrue( dijkstra.getCost() == 6.0 );
assertTrue( dijkstra.getPathAsNodes().size() == 1 );
assertTrue( dijkstra.getPathsAsNodes().size() == 1 );
}
/**
* Test case for a path of length zero, with some surrounding nodes
*/
public void testDijkstraMinimal2()
{
graph.makeEdge( "a", "b", "cost", (double) 1 );
graph.makeEdge( "a", "c", "cost", (double) 1 );
graph.makeEdge( "a", "d", "cost", (double) 1 );
graph.makeEdge( "a", "e", "cost", (double) 1 );
graph.makeEdge( "b", "c", "cost", (double) 1 );
graph.makeEdge( "c", "d", "cost", (double) 1 );
graph.makeEdge( "d", "e", "cost", (double) 1 );
graph.makeEdge( "e", "f", "cost", (double) 1 );
Dijkstra<Double> dijkstra = getDijkstra( graph, 0.0, "a", "a" );
assertTrue( dijkstra.getCost() == 0.0 );
assertTrue( dijkstra.getPathAsNodes().size() == 1 );
dijkstra = getDijkstra( graph, 3.0, "a", "a" );
assertTrue( dijkstra.getCost() == 6.0 );
assertTrue( dijkstra.getPathAsNodes().size() == 1 );
assertTrue( dijkstra.getPathAsRelationships().size() == 0 );
assertTrue( dijkstra.getPath().size() == 1 );
assertTrue( dijkstra.getPathsAsNodes().size() == 1 );
}
public void testDijkstraChain()
{
graph.makeEdge( "a", "b", "cost", (double) 1 );
graph.makeEdge( "b", "c", "cost", (double) 2 );
graph.makeEdge( "c", "d", "cost", (double) 3 );
Dijkstra<Double> dijkstra = getDijkstra( graph, 0.0, "a", "d" );
assertTrue( dijkstra.getCost() == 6.0 );
assertTrue( dijkstra.getPathAsNodes() != null );
assertTrue( dijkstra.getPathAsNodes().size() == 4 );
assertTrue( dijkstra.getPathsAsNodes().size() == 1 );
dijkstra = getDijkstra( graph, 0.0, "d", "a" );
assertTrue( dijkstra.getCost() == 6.0 );
assertTrue( dijkstra.getPathAsNodes().size() == 4 );
dijkstra = getDijkstra( graph, 0.0, "d", "b" );
assertTrue( dijkstra.getCost() == 5.0 );
assertTrue( dijkstra.getPathAsNodes().size() == 3 );
assertTrue( dijkstra.getPathAsRelationships().size() == 2 );
assertTrue( dijkstra.getPath().size() == 5 );
}
/**
* /--2--A--7--B--2--\ S E \----7---C---7----/
*/
public void testDijstraTraverserMeeting()
{
graph.makeEdge( "s", "c", "cost", (double) 7 );
graph.makeEdge( "c", "e", "cost", (double) 7 );
graph.makeEdge( "s", "a", "cost", (double) 2 );
graph.makeEdge( "a", "b", "cost", (double) 7 );
graph.makeEdge( "b", "e", "cost", (double) 2 );
Dijkstra<Double> dijkstra = getDijkstra( graph, 0.0, "s", "e" );
assertTrue( dijkstra.getCost() == 11.0 );
assertTrue( dijkstra.getPathAsNodes() != null );
assertTrue( dijkstra.getPathAsNodes().size() == 4 );
assertTrue( dijkstra.getPathsAsNodes().size() == 1 );
}
}