/**
* 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.mahout.clustering.fuzzykmeans;
import java.io.IOException;
import java.util.Iterator;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.MapReduceBase;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.Reducer;
import org.apache.hadoop.mapred.Reporter;
import org.apache.mahout.matrix.AbstractVector;
import org.apache.mahout.matrix.Vector;
public class FuzzyKMeansCombiner extends MapReduceBase implements
Reducer<Text, Text, Text, Text> {
@Override
public void reduce(Text key, Iterator<Text> values,
OutputCollector<Text, Text> output, Reporter reporter) throws IOException {
SoftCluster cluster = new SoftCluster(key.toString().trim());
while (values.hasNext()) {
String pointInfo = values.next().toString();
// check whether this is already processed
int mapperSepIndex = pointInfo
.indexOf(FuzzyKMeansDriver.MAPPER_VALUE_SEPARATOR); // ~ separator is
// used in mapper
int combinerSepIndex = pointInfo
.indexOf(FuzzyKMeansDriver.COMBINER_VALUE_SEPARATOR); // tab separator
// is used in
// combiner
int index = mapperSepIndex == -1 ? combinerSepIndex : mapperSepIndex;// needed
// to
// split
// prob and vector
double pointProb = Double.parseDouble(pointInfo.substring(0, index));
String encodedVector = pointInfo.substring(index + 1);
Vector v = AbstractVector.decodeVector(encodedVector);
if (mapperSepIndex != -1) // first time thru combiner
{
cluster.addPoint(v, Math.pow(pointProb, SoftCluster.getM()));
} else {
cluster.addPoints(v, pointProb);
}
}
output.collect(key, new Text(cluster.getPointProbSum()
+ FuzzyKMeansDriver.COMBINER_VALUE_SEPARATOR
+ cluster.getWeightedPointTotal().asFormatString()));
}
@Override
public void configure(JobConf job) {
super.configure(job);
SoftCluster.configure(job);
}
}