mapreduce/src/examples/org/apache/hadoop/examples/dancing/DistributedPentomino.java - hadoop - Git at Google

 /**
  * 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.hadoop.examples.dancing;

 import java.io.*;
 import java.util.List;
 import java.util.StringTokenizer;

 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.conf.Configured;
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.io.Text;
 import org.apache.hadoop.io.WritableComparable;
 import org.apache.hadoop.mapreduce.*;
 import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
 import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
 import org.apache.hadoop.util.*;

 /**
  * Launch a distributed pentomino solver.
  * It generates a complete list of prefixes of length N with each unique prefix
  * as a separate line. A prefix is a sequence of N integers that denote the
  * index of the row that is choosen for each column in order. Note that the
  * next column is heuristically choosen by the solver, so it is dependant on
  * the previous choice. That file is given as the input to
  * map/reduce. The output key/value are the move prefix/solution as Text/Text.
  */
 public class DistributedPentomino extends Configured implements Tool {

   private static final int PENT_DEPTH = 5;
   private static final int PENT_WIDTH = 9;
   private static final int PENT_HEIGHT = 10;
   private static final int DEFAULT_MAPS = 2000;

   /**
    * Each map takes a line, which represents a prefix move and finds all of
    * the solutions that start with that prefix. The output is the prefix as
    * the key and the solution as the value.
    */
   public static class PentMap extends
       Mapper<WritableComparable<?>, Text, Text, Text> {

     private int width;
     private int height;
     private int depth;
     private Pentomino pent;
     private Text prefixString;
     private Context context;

     /**
      * For each solution, generate the prefix and a string representation
      * of the solution. The solution starts with a newline, so that the output
      * looks like:
      * <prefix>,
      * <solution>
      *
      */
     class SolutionCatcher
     implements DancingLinks.SolutionAcceptor<Pentomino.ColumnName> {
       public void solution(List<List<Pentomino.ColumnName>> answer) {
         String board = Pentomino.stringifySolution(width, height, answer);
         try {
           context.write(prefixString, new Text("\n" + board));
           context.getCounter(pent.getCategory(answer)).increment(1);
         } catch (IOException e) {
           System.err.println(StringUtils.stringifyException(e));
         } catch (InterruptedException ie) {
           System.err.println(StringUtils.stringifyException(ie));
         }
       }
     }

     /**
      * Break the prefix string into moves (a sequence of integer row ids that
      * will be selected for each column in order). Find all solutions with
      * that prefix.
      */
     public void map(WritableComparable<?> key, Text value,Context context)
         throws IOException {
       prefixString = value;
       StringTokenizer itr = new StringTokenizer(prefixString.toString(), ",");
       int[] prefix = new int[depth];
       int idx = 0;
       while (itr.hasMoreTokens()) {
         String num = itr.nextToken();
         prefix[idx++] = Integer.parseInt(num);
       }
       pent.solve(prefix);
     }

     @Override
     public void setup(Context context) {
       this.context = context;
       Configuration conf = context.getConfiguration();
       depth = conf.getInt(Pentomino.DEPTH, PENT_DEPTH);
       width = conf.getInt(Pentomino.WIDTH, PENT_WIDTH);
       height = conf.getInt(Pentomino.HEIGHT, PENT_HEIGHT);
       pent = (Pentomino)
         ReflectionUtils.newInstance(conf.getClass(Pentomino.CLASS,
                                                   OneSidedPentomino.class),
                                     conf);
       pent.initialize(width, height);
       pent.setPrinter(new SolutionCatcher());
     }
   }

   /**
    * Create the input file with all of the possible combinations of the
    * given depth.
    * @param fs the filesystem to write into
    * @param dir the directory to write the input file into
    * @param pent the puzzle
    * @param depth the depth to explore when generating prefixes
    */
   private static long createInputDirectory(FileSystem fs,
                                            Path dir,
                                            Pentomino pent,
                                            int depth
                                            ) throws IOException {
     fs.mkdirs(dir);
     List<int[]> splits = pent.getSplits(depth);
     Path input = new Path(dir, "part1");
     PrintStream file =
       new PrintStream(new BufferedOutputStream
                       (fs.create(input), 64*1024));
     for(int[] prefix: splits) {
       for(int i=0; i < prefix.length; ++i) {
         if (i != 0) {
           file.print(',');
         }
         file.print(prefix[i]);
       }
       file.print('\n');
     }
     file.close();
     return fs.getFileStatus(input).getLen();
   }

   /**
    * Launch the solver on 9x10 board and the one sided pentominos.
    * This takes about 2.5 hours on 20 nodes with 2 cpus/node.
    * Splits the job into 2000 maps and 1 reduce.
    */
   public static void main(String[] args) throws Exception {
     int res = ToolRunner.run(new Configuration(),
                 new DistributedPentomino(), args);
     System.exit(res);
   }

   public int run(String[] args) throws Exception {
     if (args.length == 0) {
       System.out.println("pentomino <output>");
       ToolRunner.printGenericCommandUsage(System.out);
       return 2;
     }

     Configuration conf = getConf();
     int width = conf.getInt(Pentomino.WIDTH, PENT_WIDTH);
     int height = conf.getInt(Pentomino.HEIGHT, PENT_HEIGHT);
     int depth = conf.getInt(Pentomino.DEPTH, PENT_DEPTH);
     Class<? extends Pentomino> pentClass = conf.getClass(Pentomino.CLASS,
       OneSidedPentomino.class, Pentomino.class);
     int numMaps = conf.getInt(JobContext.NUM_MAPS, DEFAULT_MAPS);
     Path output = new Path(args[0]);
     Path input = new Path(output + "_input");
     FileSystem fileSys = FileSystem.get(conf);
     try {
       Job job = new Job(conf);
       FileInputFormat.setInputPaths(job, input);
       FileOutputFormat.setOutputPath(job, output);
       job.setJarByClass(PentMap.class);

       job.setJobName("dancingElephant");
       Pentomino pent = ReflectionUtils.newInstance(pentClass, conf);
       pent.initialize(width, height);
       long inputSize = createInputDirectory(fileSys, input, pent, depth);
       // for forcing the number of maps
       FileInputFormat.setMaxInputSplitSize(job, (inputSize/numMaps));

       // the keys are the prefix strings
       job.setOutputKeyClass(Text.class);
       // the values are puzzle solutions
       job.setOutputValueClass(Text.class);

       job.setMapperClass(PentMap.class);
       job.setReducerClass(Reducer.class);

       job.setNumReduceTasks(1);

       return (job.waitForCompletion(true) ? 0 : 1);
       } finally {
       fileSys.delete(input, true);
     }
   }
 }
	/**
	* 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.hadoop.examples.dancing;

	import java.io.*;
	import java.util.List;
	import java.util.StringTokenizer;

	import org.apache.hadoop.conf.Configuration;
	import org.apache.hadoop.conf.Configured;
	import org.apache.hadoop.fs.FileSystem;
	import org.apache.hadoop.fs.Path;
	import org.apache.hadoop.io.Text;
	import org.apache.hadoop.io.WritableComparable;
	import org.apache.hadoop.mapreduce.*;
	import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
	import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
	import org.apache.hadoop.util.*;

	/**
	* Launch a distributed pentomino solver.
	* It generates a complete list of prefixes of length N with each unique prefix
	* as a separate line. A prefix is a sequence of N integers that denote the
	* index of the row that is choosen for each column in order. Note that the
	* next column is heuristically choosen by the solver, so it is dependant on
	* the previous choice. That file is given as the input to
	* map/reduce. The output key/value are the move prefix/solution as Text/Text.
	*/
	public class DistributedPentomino extends Configured implements Tool {

	private static final int PENT_DEPTH = 5;
	private static final int PENT_WIDTH = 9;
	private static final int PENT_HEIGHT = 10;
	private static final int DEFAULT_MAPS = 2000;

	/**
	* Each map takes a line, which represents a prefix move and finds all of
	* the solutions that start with that prefix. The output is the prefix as
	* the key and the solution as the value.
	*/
	public static class PentMap extends
	Mapper<WritableComparable<?>, Text, Text, Text> {

	private int width;
	private int height;
	private int depth;
	private Pentomino pent;
	private Text prefixString;
	private Context context;

	/**
	* For each solution, generate the prefix and a string representation
	* of the solution. The solution starts with a newline, so that the output
	* looks like:
	* <prefix>,
	* <solution>
	*
	*/
	class SolutionCatcher
	implements DancingLinks.SolutionAcceptor<Pentomino.ColumnName> {
	public void solution(List<List<Pentomino.ColumnName>> answer) {
	String board = Pentomino.stringifySolution(width, height, answer);
	try {
	context.write(prefixString, new Text("\n" + board));
	context.getCounter(pent.getCategory(answer)).increment(1);
	} catch (IOException e) {
	System.err.println(StringUtils.stringifyException(e));
	} catch (InterruptedException ie) {
	System.err.println(StringUtils.stringifyException(ie));
	}
	}
	}

	/**
	* Break the prefix string into moves (a sequence of integer row ids that
	* will be selected for each column in order). Find all solutions with
	* that prefix.
	*/
	public void map(WritableComparable<?> key, Text value,Context context)
	throws IOException {
	prefixString = value;
	StringTokenizer itr = new StringTokenizer(prefixString.toString(), ",");
	int[] prefix = new int[depth];
	int idx = 0;
	while (itr.hasMoreTokens()) {
	String num = itr.nextToken();
	prefix[idx++] = Integer.parseInt(num);
	}
	pent.solve(prefix);
	}

	@Override
	public void setup(Context context) {
	this.context = context;
	Configuration conf = context.getConfiguration();
	depth = conf.getInt(Pentomino.DEPTH, PENT_DEPTH);
	width = conf.getInt(Pentomino.WIDTH, PENT_WIDTH);
	height = conf.getInt(Pentomino.HEIGHT, PENT_HEIGHT);
	pent = (Pentomino)
	ReflectionUtils.newInstance(conf.getClass(Pentomino.CLASS,
	OneSidedPentomino.class),
	conf);
	pent.initialize(width, height);
	pent.setPrinter(new SolutionCatcher());
	}
	}

	/**
	* Create the input file with all of the possible combinations of the
	* given depth.
	* @param fs the filesystem to write into
	* @param dir the directory to write the input file into
	* @param pent the puzzle
	* @param depth the depth to explore when generating prefixes
	*/
	private static long createInputDirectory(FileSystem fs,
	Path dir,
	Pentomino pent,
	int depth
	) throws IOException {
	fs.mkdirs(dir);
	List<int[]> splits = pent.getSplits(depth);
	Path input = new Path(dir, "part1");
	PrintStream file =
	new PrintStream(new BufferedOutputStream
	(fs.create(input), 64*1024));
	for(int[] prefix: splits) {
	for(int i=0; i < prefix.length; ++i) {
	if (i != 0) {
	file.print(',');
	}
	file.print(prefix[i]);
	}
	file.print('\n');
	}
	file.close();
	return fs.getFileStatus(input).getLen();
	}

	/**
	* Launch the solver on 9x10 board and the one sided pentominos.
	* This takes about 2.5 hours on 20 nodes with 2 cpus/node.
	* Splits the job into 2000 maps and 1 reduce.
	*/
	public static void main(String[] args) throws Exception {
	int res = ToolRunner.run(new Configuration(),
	new DistributedPentomino(), args);
	System.exit(res);
	}

	public int run(String[] args) throws Exception {
	if (args.length == 0) {
	System.out.println("pentomino <output>");
	ToolRunner.printGenericCommandUsage(System.out);
	return 2;
	}

	Configuration conf = getConf();
	int width = conf.getInt(Pentomino.WIDTH, PENT_WIDTH);
	int height = conf.getInt(Pentomino.HEIGHT, PENT_HEIGHT);
	int depth = conf.getInt(Pentomino.DEPTH, PENT_DEPTH);
	Class<? extends Pentomino> pentClass = conf.getClass(Pentomino.CLASS,
	OneSidedPentomino.class, Pentomino.class);
	int numMaps = conf.getInt(JobContext.NUM_MAPS, DEFAULT_MAPS);
	Path output = new Path(args[0]);
	Path input = new Path(output + "_input");
	FileSystem fileSys = FileSystem.get(conf);
	try {
	Job job = new Job(conf);
	FileInputFormat.setInputPaths(job, input);
	FileOutputFormat.setOutputPath(job, output);
	job.setJarByClass(PentMap.class);

	job.setJobName("dancingElephant");
	Pentomino pent = ReflectionUtils.newInstance(pentClass, conf);
	pent.initialize(width, height);
	long inputSize = createInputDirectory(fileSys, input, pent, depth);
	// for forcing the number of maps
	FileInputFormat.setMaxInputSplitSize(job, (inputSize/numMaps));

	// the keys are the prefix strings
	job.setOutputKeyClass(Text.class);
	// the values are puzzle solutions
	job.setOutputValueClass(Text.class);

	job.setMapperClass(PentMap.class);
	job.setReducerClass(Reducer.class);

	job.setNumReduceTasks(1);

	return (job.waitForCompletion(true) ? 0 : 1);
	} finally {
	fileSys.delete(input, true);
	}
	}
	}