boostingPL.MR.AdaBoostPLMapper.java Source code

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Here is the source code for boostingPL.MR.AdaBoostPLMapper.java

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/*
 *   BoostingPL - Scalable and Parallel Boosting with MapReduce 
 *   Copyright (C) 2012  Ranler Cao  findfunaax@gmail.com
 *
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.   
 */

package boostingPL.MR;

import java.io.IOException;

import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Counter;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.util.LineReader;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import weka.classifiers.Classifier;
import weka.core.Instances;

import boosting.classifiers.ClassifierWritable;
import boostingPL.boosting.Boosting;
import boostingPL.boosting.BoostingPLFactory;
import boostingPL.boosting.InstancesHelper;
import boostingPL.utils.Sort;

public class AdaBoostPLMapper extends Mapper<LongWritable, Text, IntWritable, ClassifierWritable> {

    private static final Logger LOG = LoggerFactory.getLogger(AdaBoostPLMapper.class);

    private Instances insts = null;

    /** create instances header */
    protected void setup(Context context) throws IOException, InterruptedException {
        String pathSrc = context.getConfiguration().get("BoostingPL.metadata");
        FileSystem hdfs = FileSystem.get(context.getConfiguration());
        FSDataInputStream dis = new FSDataInputStream(hdfs.open(new Path(pathSrc)));
        LineReader in = new LineReader(dis);
        insts = InstancesHelper.createInstancesFromMetadata(in);
        in.close();
        dis.close();
    }

    protected void map(LongWritable key, Text value, Context context) {
        insts.add(InstancesHelper.createInstance(value.toString(), insts));
    }

    protected void cleanup(Context context) throws IOException, InterruptedException {
        int T = Integer.parseInt(context.getConfiguration().get("BoostingPL.numIterations"));
        System.out.println("Iteration = " + T);

        String boostingName = context.getConfiguration().get("BoostingPL.boostingName");
        Boosting boosting = BoostingPLFactory.createBoosting(boostingName, insts, T);
        Counter iterationCounter = context.getCounter("BoostingPL", "current iterations");
        try {
            for (int t = 0; t < T; t++) {
                boosting.run(t);
                context.progress();
                iterationCounter.increment(1);
            }
        } catch (Exception e) {
            LOG.error(e.toString());
            return;
        }

        double[] corWeights = boosting.getClasifiersWeights();
        Classifier[] classifiers = boosting.getClassifiers();
        int taskid = context.getTaskAttemptID().getTaskID().getId();

        Sort.sort(classifiers, corWeights);

        for (int i = 0; i < classifiers.length; i++) {
            System.out.println("nodeid=" + taskid + " cweight=" + corWeights[i]);
            context.write(new IntWritable(taskid), new ClassifierWritable(classifiers[i], corWeights[i]));
        }
    }
}