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Posted to commits@commons.apache.org by si...@apache.org on 2011/06/30 21:47:47 UTC
svn commit: r1141686 - in /commons/sandbox/graph/trunk/src:
main/java/org/apache/commons/graph/shortestpath/BellmannFord.java
test/java/org/apache/commons/graph/shortestpath/BellmannFordTestCase.java
Author: simonetripodi
Date: Thu Jun 30 19:47:47 2011
New Revision: 1141686
URL: http://svn.apache.org/viewvc?rev=1141686&view=rev
Log:
first checkin of BellmannFordTestCase
fixed BellmannFord algorithm (changed also the signature, it is the single source algorithm)
Added:
commons/sandbox/graph/trunk/src/test/java/org/apache/commons/graph/shortestpath/BellmannFordTestCase.java (with props)
Modified:
commons/sandbox/graph/trunk/src/main/java/org/apache/commons/graph/shortestpath/BellmannFord.java
Modified: commons/sandbox/graph/trunk/src/main/java/org/apache/commons/graph/shortestpath/BellmannFord.java
URL: http://svn.apache.org/viewvc/commons/sandbox/graph/trunk/src/main/java/org/apache/commons/graph/shortestpath/BellmannFord.java?rev=1141686&r1=1141685&r2=1141686&view=diff
==============================================================================
--- commons/sandbox/graph/trunk/src/main/java/org/apache/commons/graph/shortestpath/BellmannFord.java (original)
+++ commons/sandbox/graph/trunk/src/main/java/org/apache/commons/graph/shortestpath/BellmannFord.java Thu Jun 30 19:47:47 2011
@@ -50,30 +50,32 @@ public final class BellmannFord
* @param target the shortest path target Vertex
* @return a path which describes the shortest path, if any, otherwise a {@link PathNotFoundException} will be thrown
*/
- public static <V extends Vertex, WE extends WeightedEdge, G extends WeightedGraph<V, WE> & DirectedGraph<V, WE>> WeightedPath<V, WE> findShortestPath( G graph,
- V source,
- V target )
+ public static <V extends Vertex, WE extends WeightedEdge, G extends WeightedGraph<V, WE> & DirectedGraph<V, WE>> AllVertexPairsShortestPath<V, WE> findShortestPath( G graph,
+ V source)
{
final ShortestDistances<V> shortestDistances = new ShortestDistances<V>();
shortestDistances.setWeight( source, 0D );
final PredecessorsList<V, WE> predecessors = new PredecessorsList<V, WE>( graph );
- for ( WE edge : graph.getEdges() )
+ for ( int i = 0; i < graph.getOrder(); i++ )
{
- VertexPair<V> vertexPair = graph.getVertices( edge );
- V u = vertexPair.getHead();
- V v = vertexPair.getTail();
-
- Double shortDist = shortestDistances.getWeight( u ) + edge.getWeight();
-
- if ( shortDist.compareTo( shortestDistances.getWeight( v ) ) < 0 )
+ for ( WE edge : graph.getEdges() )
{
- // assign new shortest distance and mark unsettled
- shortestDistances.setWeight( v, shortDist );
-
- // assign predecessor in shortest path
- predecessors.addPredecessor( v, u );
+ VertexPair<V> vertexPair = graph.getVertices( edge );
+ V u = vertexPair.getHead();
+ V v = vertexPair.getTail();
+
+ Double shortDist = shortestDistances.getWeight( u ) + edge.getWeight();
+
+ if ( shortDist.compareTo( shortestDistances.getWeight( v ) ) < 0 )
+ {
+ // assign new shortest distance and mark unsettled
+ shortestDistances.setWeight( v, shortDist );
+
+ // assign predecessor in shortest path
+ predecessors.addPredecessor( v, u );
+ }
}
}
@@ -93,7 +95,18 @@ public final class BellmannFord
}
}
- return null;
+ AllVertexPairsShortestPath<V, WE> allVertexPairsShortestPath = new AllVertexPairsShortestPath<V, WE>();
+
+ for ( V target : graph.getVertices() )
+ {
+ if ( !source.equals( target ) )
+ {
+ WeightedPath<V, WE> weightedPath = predecessors.buildPath( source, target );
+ allVertexPairsShortestPath.addShortestPath( source, target, weightedPath );
+ }
+ }
+
+ return allVertexPairsShortestPath;
}
}
Added: commons/sandbox/graph/trunk/src/test/java/org/apache/commons/graph/shortestpath/BellmannFordTestCase.java
URL: http://svn.apache.org/viewvc/commons/sandbox/graph/trunk/src/test/java/org/apache/commons/graph/shortestpath/BellmannFordTestCase.java?rev=1141686&view=auto
==============================================================================
--- commons/sandbox/graph/trunk/src/test/java/org/apache/commons/graph/shortestpath/BellmannFordTestCase.java (added)
+++ commons/sandbox/graph/trunk/src/test/java/org/apache/commons/graph/shortestpath/BellmannFordTestCase.java Thu Jun 30 19:47:47 2011
@@ -0,0 +1,92 @@
+package org.apache.commons.graph.shortestpath;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import static junit.framework.Assert.assertEquals;
+import static org.apache.commons.graph.shortestpath.BellmannFord.findShortestPath;
+
+import org.apache.commons.graph.WeightedPath;
+import org.apache.commons.graph.model.BaseLabeledVertex;
+import org.apache.commons.graph.model.BaseLabeledWeightedEdge;
+import org.apache.commons.graph.model.DirectedMutableWeightedGraph;
+import org.apache.commons.graph.model.InMemoryWeightedPath;
+import org.junit.Test;
+
+public final class BellmannFordTestCase
+{
+
+ /**
+ * Test Graph and Dijkstra's solution can be seen on
+ * <a href="http://compprog.wordpress.com/2007/11/29/one-source-shortest-path-the-bellman-ford-algorithm/">Wikipedia</a>
+ */
+ @Test
+ public void findShortestPathAndVerify()
+ {
+ // the input graph
+ DirectedMutableWeightedGraph<BaseLabeledVertex, BaseLabeledWeightedEdge> graph =
+ new DirectedMutableWeightedGraph<BaseLabeledVertex, BaseLabeledWeightedEdge>();
+
+ BaseLabeledVertex one = new BaseLabeledVertex( "1" );
+ BaseLabeledVertex two = new BaseLabeledVertex( "2" );
+ BaseLabeledVertex three = new BaseLabeledVertex( "3" );
+ BaseLabeledVertex four = new BaseLabeledVertex( "4" );
+ BaseLabeledVertex five = new BaseLabeledVertex( "5" );
+
+ graph.addVertex( one );
+ graph.addVertex( two );
+ graph.addVertex( three );
+ graph.addVertex( four );
+ graph.addVertex( five );
+
+ graph.addEdge( one, new BaseLabeledWeightedEdge( "1 -> 2", 6D ), two );
+ graph.addEdge( one, new BaseLabeledWeightedEdge( "1 -> 4", 7D ), four );
+
+ graph.addEdge( two, new BaseLabeledWeightedEdge( "2 -> 3", 5D ), three );
+ graph.addEdge( two, new BaseLabeledWeightedEdge( "2 -> 5", -4D ), five );
+ graph.addEdge( two, new BaseLabeledWeightedEdge( "2 -> 4", 8D ), four );
+
+ graph.addEdge( three, new BaseLabeledWeightedEdge( "3 -> 2", -2D ), two );
+
+ graph.addEdge( four, new BaseLabeledWeightedEdge( "4 -> 3", -3D ), three );
+ graph.addEdge( four, new BaseLabeledWeightedEdge( "4 -> 5", 9D ), five );
+
+ graph.addEdge( five, new BaseLabeledWeightedEdge( "5 -> 3", 7D ), three );
+ graph.addEdge( five, new BaseLabeledWeightedEdge( "5 -> 1", 2D ), one );
+
+ // the expected weighted path
+ InMemoryWeightedPath<BaseLabeledVertex, BaseLabeledWeightedEdge> expected =
+ new InMemoryWeightedPath<BaseLabeledVertex, BaseLabeledWeightedEdge>( one, three );
+ expected.addVertexInTail( one );
+ expected.addVertexInTail( four );
+ expected.addVertexInTail( three );
+
+ expected.addEdgeInTail( new BaseLabeledWeightedEdge( "1 -> 4", 7D ) );
+ expected.addEdgeInTail( new BaseLabeledWeightedEdge( "4 -> 3", -3D ) );
+
+ // the actual weighted path
+ AllVertexPairsShortestPath<BaseLabeledVertex, BaseLabeledWeightedEdge> allVertexPairsShortestPath =
+ findShortestPath( graph, one );
+
+ WeightedPath<BaseLabeledVertex, BaseLabeledWeightedEdge> actual =
+ allVertexPairsShortestPath.findShortestPath( one, three );
+ assertEquals( expected, actual );
+ }
+
+}
Propchange: commons/sandbox/graph/trunk/src/test/java/org/apache/commons/graph/shortestpath/BellmannFordTestCase.java
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