/*

  * 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.benchmark;

 import java.io.DataInput;

 import java.io.DataOutput;

 import java.io.IOException;

 import java.util.Set;

 import org.apache.commons.cli.CommandLine;

 import org.apache.giraph.conf.GiraphConfiguration;

 import org.apache.giraph.conf.GiraphConstants;

 import org.apache.giraph.graph.BasicComputation;

 import org.apache.giraph.graph.Vertex;

 import org.apache.giraph.io.formats.PseudoRandomInputFormatConstants;

 import org.apache.giraph.io.formats.PseudoRandomVertexInputFormat;

 import org.apache.giraph.master.DefaultMasterCompute;

 import org.apache.giraph.reducers.ReduceSameTypeOperation;

 import org.apache.giraph.worker.DefaultWorkerContext;

 import org.apache.hadoop.conf.Configuration;

 import org.apache.hadoop.io.DoubleWritable;

 import org.apache.hadoop.io.LongWritable;

 import org.apache.hadoop.util.ToolRunner;

 import com.google.common.collect.Sets;

 /**

  * Benchmark for reducers. Also checks the correctness.

  */

 public class ReducersBenchmark extends GiraphBenchmark {

   /** Number of reducers setting */

   private static final String REDUCERS_NUM = "reducersbenchmark.num";

   /** Option for number of reducers */

   private static final BenchmarkOption REDUCERS =

       new BenchmarkOption("r", "reducers",

           true, "Reducers", "Need to set number of reducers (-r)");

   /** LongSumReducer */

   public static class TestLongSumReducer

       extends ReduceSameTypeOperation<LongWritable> {

     /** Singleton */

     public static final TestLongSumReducer INSTANCE = new TestLongSumReducer();

     @Override

     public LongWritable createInitialValue() {

       return new LongWritable();

     }

     @Override

     public LongWritable reduce(

         LongWritable curValue, LongWritable valueToReduce) {

       curValue.set(curValue.get() + valueToReduce.get());

       return curValue;

     }

     @Override

     public void readFields(DataInput in) throws IOException {

     }

     @Override

     public void write(DataOutput out) throws IOException {

     }

   }

   /**

    * Vertex class for ReducersBenchmark

    */

   public static class ReducersBenchmarkComputation extends

       BasicComputation<LongWritable, DoubleWritable, DoubleWritable,

           DoubleWritable> {

     @Override

     public void compute(

         Vertex<LongWritable, DoubleWritable, DoubleWritable> vertex,

         Iterable<DoubleWritable> messages) throws IOException {

       int n = getNumReducers(getConf());

       long superstep = getSuperstep();

       int w = getWorkerContextReduced(getConf(), superstep);

       for (int i = 0; i < n; i++) {

         reduce("w" + i, new LongWritable((superstep + 1) * i));

         reduce("p" + i, new LongWritable(i));

         if (superstep > 0) {

           assertEquals(superstep * (getTotalNumVertices() * i) + w,

               ((LongWritable) getBroadcast("w" + i)).get());

           assertEquals(-(superstep * i),

               ((LongWritable) getBroadcast("m" + i)).get());

           assertEquals(superstep * getTotalNumVertices() * i,

               ((LongWritable) getBroadcast("p" + i)).get());

         }

       }

       if (superstep > 2) {

         vertex.voteToHalt();

       }

     }

   }

   /**

    * MasterCompute class for ReducersBenchmark

    */

   public static class ReducersBenchmarkMasterCompute extends

       DefaultMasterCompute {

     @Override

     public void compute() {

       int n = getNumReducers(getConf());

       long superstep = getSuperstep();

       int w = getWorkerContextReduced(getConf(), superstep);

       for (int i = 0; i < n; i++) {

         String wi = "w" + i;

         String mi = "m" + i;

         String pi = "p" + i;

         registerReducer(wi, TestLongSumReducer.INSTANCE);

         registerReducer(mi, new TestLongSumReducer());

         if (superstep > 0) {

           broadcast(wi, getReduced(wi));

           broadcast(mi, new LongWritable(-superstep * i));

           broadcast(pi, getReduced(pi));

           registerReducer(pi, new TestLongSumReducer(),

               (LongWritable) getReduced(pi));

           assertEquals(superstep * (getTotalNumVertices() * i) + w,

               ((LongWritable) getReduced(wi)).get());

           assertEquals(superstep * getTotalNumVertices() * i,

               ((LongWritable) getReduced(pi)).get());

         } else {

           registerReducer(pi, new TestLongSumReducer());

         }

       }

     }

   }

   /**

    * WorkerContext class for ReducersBenchmark

    */

   public static class ReducersBenchmarkWorkerContext

       extends DefaultWorkerContext {

     @Override

     public void preSuperstep() {

       addToWorkerReducers(1);

       checkReducers();

     }

     @Override

     public void postSuperstep() {

       addToWorkerReducers(2);

       checkReducers();

     }

     /**

      * Check if reducer values are correct for current superstep

      */

     private void checkReducers() {

       int n = getNumReducers(getContext().getConfiguration());

       long superstep = getSuperstep();

       int w = getWorkerContextReduced(

           getContext().getConfiguration(), superstep);

       for (int i = 0; i < n; i++) {

         if (superstep > 0) {

           assertEquals(superstep * (getTotalNumVertices() * i) + w,

               ((LongWritable) getBroadcast("w" + i)).get());

           assertEquals(-(superstep * i),

               ((LongWritable) getBroadcast("m" + i)).get());

           assertEquals(superstep * getTotalNumVertices() * i,

               ((LongWritable) getBroadcast("p" + i)).get());

         }

       }

     }

     /**

      * Add some value to worker reducers.

      *

      * @param valueToAdd Which value to add

      */

     private void addToWorkerReducers(int valueToAdd) {

       int n = getNumReducers(getContext().getConfiguration());

       for (int i = 0; i < n; i++) {

         reduce("w" + i, new LongWritable(valueToAdd));

       }

     }

   }

   /**

    * Get the number of reducers from configuration

    *

    * @param conf Configuration

    * @return Number of reducers

    */

   private static int getNumReducers(Configuration conf) {

     return conf.getInt(REDUCERS_NUM, 0);

   }

   /**

    * Get the value which should be reduced by worker context

    *

    * @param conf Configuration

    * @param superstep Superstep

    * @return The value which should be reduced by worker context

    */

   private static int getWorkerContextReduced(Configuration conf,

       long superstep) {

     return (superstep <= 0) ? 0 : conf.getInt("workers", 0) * 3;

   }

   /**

    * Check if values are equal, throw an exception if they aren't

    *

    * @param expected Expected value

    * @param actual Actual value

    */

   private static void assertEquals(long expected, long actual) {

     if (expected != actual) {

       throw new RuntimeException("expected: " + expected +

           ", actual: " + actual);

     }

   }

   @Override

   public Set<BenchmarkOption> getBenchmarkOptions() {

     return Sets.newHashSet(BenchmarkOption.VERTICES, REDUCERS);

   }

   @Override

   protected void prepareConfiguration(GiraphConfiguration conf,

       CommandLine cmd) {

     conf.setComputationClass(ReducersBenchmarkComputation.class);

     conf.setMasterComputeClass(ReducersBenchmarkMasterCompute.class);

     conf.setVertexInputFormatClass(PseudoRandomVertexInputFormat.class);

     conf.setWorkerContextClass(ReducersBenchmarkWorkerContext.class);

     conf.setLong(PseudoRandomInputFormatConstants.AGGREGATE_VERTICES,

         BenchmarkOption.VERTICES.getOptionLongValue(cmd));

     conf.setLong(PseudoRandomInputFormatConstants.EDGES_PER_VERTEX, 1);

     conf.setInt(REDUCERS_NUM, REDUCERS.getOptionIntValue(cmd));

     conf.setInt("workers", conf.getInt(GiraphConstants.MAX_WORKERS, -1));

   }

   /**

    * Execute the benchmark.

    *

    * @param args Typically the command line arguments.

    * @throws Exception Any exception from the computation.

    */

   public static void main(final String[] args) throws Exception {

     System.exit(ToolRunner.run(new ReducersBenchmark(), args));

   }

 }