/*

  * 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.

  */

 package org.apache.giraph.block_app.test_setup.graphs;

 import java.util.Random;

 import org.apache.giraph.block_app.test_setup.NumericTestGraph;

 import org.apache.giraph.block_app.test_setup.TestGraphModifier;

 import org.apache.giraph.conf.FloatConfOption;

 import org.apache.giraph.conf.GiraphConfiguration;

 import org.apache.giraph.conf.IntConfOption;

 import org.apache.giraph.function.Supplier;

 import org.apache.hadoop.io.Writable;

 import org.apache.hadoop.io.WritableComparable;

 /**

  * Creates synthetic graphs, that can have community structure.

  *

  * @param <I> Vertex id type

  * @param <V> Vertex value type

  * @param <E> Edge value type

  */

 public class SyntheticGraphInit<I extends WritableComparable,

     V extends Writable, E extends Writable>

     implements TestGraphModifier<I, V, E> {

   public static final IntConfOption NUM_COMMUNITIES = new IntConfOption(

       "test.SyntheticGraphCreator.NUM_COMMUNITIES", -1, "");

   public static final IntConfOption NUM_VERTICES = new IntConfOption(

       "test.SyntheticGraphCreator.NUM_VERTICES", -1, "");

   public static final IntConfOption NUM_EDGES_PER_VERTEX = new IntConfOption(

       "test.SyntheticGraphCreator.NUM_EDGES_PER_VERTEX", -1, "");

   public static final FloatConfOption ACTUAL_LOCALITY_RATIO =

       new FloatConfOption(

             "test.SyntheticGraphCreator.ACTUAL_LOCALITY_RATIO", -1, "");

   protected final Supplier<E> edgeSupplier;

   public SyntheticGraphInit(Supplier<E> edgeSupplier) {

     this.edgeSupplier = edgeSupplier;

   }

   public SyntheticGraphInit() {

     this.edgeSupplier = null;

   }

   @Override

   public void modifyGraph(NumericTestGraph<I, V, E> graph) {

     GiraphConfiguration conf = graph.getConf();

     int numPartitions = NUM_COMMUNITIES.get(conf);

     int numVertices = NUM_VERTICES.get(conf);

     int numEdgesPerVertex = NUM_EDGES_PER_VERTEX.get(conf);

     int communitySize = numVertices / numPartitions;

     float actualLocalityRatio = ACTUAL_LOCALITY_RATIO.get(conf);

     Random random = new Random(42);

     for (int i = 0; i < numVertices; ++i) {

       for (int e = 0; e < numEdgesPerVertex / 2; ++e) {

         boolean localEdge = random.nextFloat() < actualLocalityRatio;

         int community = i / communitySize;

         int j;

         do {

           if (localEdge) {

             j = community * communitySize + random.nextInt(communitySize);

           } else {

             j = random.nextInt(numVertices);

           }

         } while (j == i);

         graph.addSymmetricEdge(

             i, j, edgeSupplier != null ? edgeSupplier.get() : null);

       }

     }

   }

 }