/**
* 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.canopy;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.Writable;
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;
import java.io.IOException;
import java.util.Iterator;
public class CanopyCombiner 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 {
Writable value = values.next();
Vector center = AbstractVector.decodeVector(value.toString());
Canopy canopy = new Canopy(center);
while (values.hasNext()) {
value = values.next();
Vector point = AbstractVector.decodeVector(value.toString());
canopy.addPoint(point);
}
output.collect(new Text("centroid"), new Text(canopy.computeCentroid()
.asFormatString()));
}
@Override
public void configure(JobConf job) {
super.configure(job);
Canopy.configure(job);
}
}