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From simonetrip...@apache.org
Subject svn commit: r1140557 - in /commons/sandbox/graph/trunk/src: main/java/org/apache/commons/graph/coloring/ test/java/org/apache/commons/graph/coloring/ test/java/org/apache/commons/graph/utils/
Date Tue, 28 Jun 2011 12:18:37 GMT
Author: simonetripodi
Date: Tue Jun 28 12:18:36 2011
New Revision: 1140557

URL: http://svn.apache.org/viewvc?rev=1140557&view=rev
Log:
[SANDBOX-333] Graph coloring implementation - patch provided  by Marco Speranza

Added:
    commons/sandbox/graph/trunk/src/main/java/org/apache/commons/graph/coloring/
    commons/sandbox/graph/trunk/src/main/java/org/apache/commons/graph/coloring/GraphColoring.java
  (with props)
    commons/sandbox/graph/trunk/src/test/java/org/apache/commons/graph/coloring/
    commons/sandbox/graph/trunk/src/test/java/org/apache/commons/graph/coloring/GraphColoringTestCase.java
  (with props)
    commons/sandbox/graph/trunk/src/test/java/org/apache/commons/graph/utils/
    commons/sandbox/graph/trunk/src/test/java/org/apache/commons/graph/utils/GraphUtils.java
  (with props)

Added: commons/sandbox/graph/trunk/src/main/java/org/apache/commons/graph/coloring/GraphColoring.java
URL: http://svn.apache.org/viewvc/commons/sandbox/graph/trunk/src/main/java/org/apache/commons/graph/coloring/GraphColoring.java?rev=1140557&view=auto
==============================================================================
--- commons/sandbox/graph/trunk/src/main/java/org/apache/commons/graph/coloring/GraphColoring.java
(added)
+++ commons/sandbox/graph/trunk/src/main/java/org/apache/commons/graph/coloring/GraphColoring.java
Tue Jun 28 12:18:36 2011
@@ -0,0 +1,134 @@
+package org.apache.commons.graph.coloring;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
+
+import org.apache.commons.graph.Edge;
+import org.apache.commons.graph.UndirectedGraph;
+import org.apache.commons.graph.Vertex;
+
+/*
+ * 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.
+ */
+
+/**
+ * Contains the graph coloring implementation. http://scienceblogs.com/goodmath/2007/06/graph_coloring_algorithms_1.php
+ */
+public final class GraphColoring
+{
+
+    /**
+     * Return the color number of the graph. The color number is the minimal number of colors
needed to color each
+     * vertex such that no two adjacent vertices share the same color.
+     *
+     * @param g The graph.
+     * @return the graph color number.
+     */
+    public static <V extends Vertex, E extends Edge> int colorNumber( UndirectedGraph<V,
E> g )
+    {
+        Map<V, Integer> coloredVertices = coloring( g );
+        return Collections.max( coloredVertices.values() ) + 1;
+    }
+
+    /**
+     * Colors the graph such that no two adjacent vertices share the same color.
+     *
+     * @param g The graph.
+     * @return The color - vertex association.
+     */
+    public static <V extends Vertex, E extends Edge> Map<V, Integer> coloring(
UndirectedGraph<V, E> g )
+    {
+        Map<V, Integer> coloredVertices = new HashMap<V, Integer>();
+        List<V> uncoloredVertices = null;
+
+        // decreasing sorting all vertices by degree.
+        Map<Integer, List<V>> orderedVertex = new TreeMap<Integer, List<V>>(
new Comparator<Integer>()
+        {
+            public int compare( Integer o1, Integer o2 )
+            {
+                return o1.compareTo( o2 ) * -1;
+            }
+        } );
+
+        for ( V v : g.getVertices() )
+        {
+            int degree = g.getDegree( v );
+            List<V> vertices = orderedVertex.get( degree );
+
+            if ( vertices == null )
+            {
+                vertices = new ArrayList<V>();
+            }
+
+            vertices.add( v );
+            orderedVertex.put( degree, vertices );
+        }
+
+        uncoloredVertices = new ArrayList<V>();
+        for ( Integer key : orderedVertex.keySet() )
+        {
+            uncoloredVertices.addAll( orderedVertex.get( key ) );
+        }
+
+        // search coloring
+        int currrentColorIndex = 0;
+
+        Iterator<V> it = uncoloredVertices.iterator();
+        while ( it.hasNext() )
+        {
+            V v = it.next();
+
+            // remove vertex from uncolored list.
+            it.remove();
+            coloredVertices.put( v, currrentColorIndex );
+
+            // color all vertex not adiacent
+            Iterator<V> it2 = uncoloredVertices.iterator();
+            while ( it2.hasNext() )
+            {
+                V v2 = it2.next();
+                if ( g.getEdge( v, v2 ) == null )
+                {
+                    // v2 is not connect to v.
+                    it2.remove();
+                    coloredVertices.put( v2, currrentColorIndex );
+                }
+            }
+
+            it = uncoloredVertices.iterator();
+            currrentColorIndex++;
+        }
+
+        return coloredVertices;
+    }
+
+    /**
+     * This class can not be instantiated.
+     */
+    private GraphColoring()
+    {
+        // do nothing
+    }
+
+}

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Added: commons/sandbox/graph/trunk/src/test/java/org/apache/commons/graph/coloring/GraphColoringTestCase.java
URL: http://svn.apache.org/viewvc/commons/sandbox/graph/trunk/src/test/java/org/apache/commons/graph/coloring/GraphColoringTestCase.java?rev=1140557&view=auto
==============================================================================
--- commons/sandbox/graph/trunk/src/test/java/org/apache/commons/graph/coloring/GraphColoringTestCase.java
(added)
+++ commons/sandbox/graph/trunk/src/test/java/org/apache/commons/graph/coloring/GraphColoringTestCase.java
Tue Jun 28 12:18:36 2011
@@ -0,0 +1,92 @@
+package org.apache.commons.graph.coloring;
+
+/*
+ * 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 org.apache.commons.graph.coloring.GraphColoring.colorNumber;
+import static org.apache.commons.graph.utils.GraphUtils.buildBipartedGraph;
+import static org.apache.commons.graph.utils.GraphUtils.buildCompleteGraph;
+import static org.junit.Assert.assertEquals;
+
+import org.apache.commons.graph.Edge;
+import org.apache.commons.graph.Vertex;
+import org.apache.commons.graph.model.BaseLabeledEdge;
+import org.apache.commons.graph.model.BaseLabeledVertex;
+import org.apache.commons.graph.model.UndirectedMutableGraph;
+import org.junit.Test;
+
+/**
+ * 
+ */
+public class GraphColoringTestCase
+{
+
+    @Test
+    public void testCromaticNumber()
+    {
+        UndirectedMutableGraph<BaseLabeledVertex, BaseLabeledEdge> g = new UndirectedMutableGraph<BaseLabeledVertex,
BaseLabeledEdge>();
+
+        BaseLabeledVertex one = new BaseLabeledVertex( "1" );
+        BaseLabeledVertex two = new BaseLabeledVertex( "2" );
+        BaseLabeledVertex three = new BaseLabeledVertex( "3" );
+
+        g.addVertex( one );
+        g.addVertex( two );
+        g.addVertex( three );
+
+        g.addEdge( one, new BaseLabeledEdge( "1 -> 2" ), two );
+        g.addEdge( two, new BaseLabeledEdge( "2 -> 3" ), three );
+        g.addEdge( three, new BaseLabeledEdge( "3 -> 1" ), one );
+
+        assertEquals( 3, colorNumber( g ) );
+    }
+
+    @Test
+    public void testCromaticNumberComplete()
+    {
+        UndirectedMutableGraph<BaseLabeledVertex, BaseLabeledEdge> g1 =
+            new UndirectedMutableGraph<BaseLabeledVertex, BaseLabeledEdge>();
+        buildCompleteGraph( 100, g1 );
+
+        assertEquals( 100, colorNumber( g1 ) );
+    }
+
+    @Test
+    public void testCromaticNumberBiparted()
+    {
+        UndirectedMutableGraph<BaseLabeledVertex, BaseLabeledEdge> g1 =
+            new UndirectedMutableGraph<BaseLabeledVertex, BaseLabeledEdge>();
+        buildBipartedGraph( 100, g1 );
+
+        assertEquals( 2, colorNumber( g1 ) );
+    }
+
+    @Test
+    public void testCromaticNumberSparseGraph()
+    {
+        UndirectedMutableGraph<Vertex, Edge> g1 = new UndirectedMutableGraph<Vertex,
Edge>();
+        for ( int i = 0; i < 100; i++ )
+        {
+            g1.addVertex( new BaseLabeledVertex( "" + i ) );
+        }
+
+        assertEquals( 1, colorNumber( g1 ) );
+    }
+
+}

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Added: commons/sandbox/graph/trunk/src/test/java/org/apache/commons/graph/utils/GraphUtils.java
URL: http://svn.apache.org/viewvc/commons/sandbox/graph/trunk/src/test/java/org/apache/commons/graph/utils/GraphUtils.java?rev=1140557&view=auto
==============================================================================
--- commons/sandbox/graph/trunk/src/test/java/org/apache/commons/graph/utils/GraphUtils.java
(added)
+++ commons/sandbox/graph/trunk/src/test/java/org/apache/commons/graph/utils/GraphUtils.java
Tue Jun 28 12:18:36 2011
@@ -0,0 +1,120 @@
+package org.apache.commons.graph.utils;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.apache.commons.graph.model.BaseLabeledEdge;
+import org.apache.commons.graph.model.BaseLabeledVertex;
+import org.apache.commons.graph.model.UndirectedMutableGraph;
+
+/*
+ * 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.
+ */
+
+/**
+ * Utilities graph class.
+ */
+public class GraphUtils
+{
+
+    /**
+     * Creates a complete graph with nVertices
+     *
+     * @param nVertices number of vertices
+     * @param g graph
+     */
+    public static void buildCompleteGraph( int nVertices, UndirectedMutableGraph<BaseLabeledVertex,
BaseLabeledEdge> g )
+    {
+        // building Graph
+        for ( int i = 0; i < nVertices; i++ )
+        {
+            BaseLabeledVertex v = new BaseLabeledVertex( "" + i );
+            g.addVertex( v );
+        }
+
+        for ( BaseLabeledVertex v1 : g.getVertices() )
+        {
+            for ( BaseLabeledVertex v2 : g.getVertices() )
+            {
+                if ( !v1.equals( v2 ) )
+                {
+                    g.addEdge( v1, new BaseLabeledEdge( "" ), v2 );
+                }
+            }
+        }
+    }
+
+    /**
+     * Create a Biparted graph
+     *
+     * @param nVertices number of vertices
+     * @param g graph
+     */
+    public static void buildBipartedGraph( int nVertices, UndirectedMutableGraph<BaseLabeledVertex,
BaseLabeledEdge> g )
+    {
+        // building Graph
+        for ( int i = 0; i < nVertices; i++ )
+        {
+            BaseLabeledVertex v = new BaseLabeledVertex( "" + i );
+            g.addVertex( v );
+        }
+
+        List<BaseLabeledVertex> fistPartition = new ArrayList<BaseLabeledVertex>();
+        List<BaseLabeledVertex> secondPartition = new ArrayList<BaseLabeledVertex>();
+
+        int count = 0;
+        for ( BaseLabeledVertex v1 : g.getVertices() )
+        {
+            if ( count++ == nVertices / 2 )
+            {
+                break;
+            }
+            fistPartition.add( v1 );
+        }
+
+        count = 0;
+        for ( BaseLabeledVertex v2 : g.getVertices() )
+        {
+            if ( count++ < nVertices / 2 )
+            {
+                continue;
+            }
+            secondPartition.add( v2 );
+        }
+
+        for ( BaseLabeledVertex v1 : fistPartition )
+        {
+            for ( BaseLabeledVertex v2 : secondPartition )
+            {
+                if ( !v1.equals( v2 ) )
+                {
+                    g.addEdge( v1, new BaseLabeledEdge( "" ), v2 );
+                }
+            }
+        }
+    }
+
+    /**
+     * This class can't be instantiated
+     */
+    private GraphUtils()
+    {
+        // do nothing
+    }
+
+}

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