package org.apache.mahout.vectorizer.pruner;
/**
* 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.
*/
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.mahout.math.Vector;
import org.apache.mahout.math.VectorWritable;
import org.apache.mahout.math.function.Functions;
import org.apache.mahout.vectorizer.common.PartialVectorMerger;
import java.io.IOException;
public class PrunedPartialVectorMergeReducer extends
Reducer<WritableComparable<?>, VectorWritable, WritableComparable<?>, VectorWritable> {
private double normPower;
private boolean logNormalize;
@Override
protected void reduce(WritableComparable<?> key, Iterable<VectorWritable> values, Context context) throws IOException,
InterruptedException {
Vector vector = null;
for (VectorWritable value : values) {
if (vector == null) {
vector = value.get().clone();
continue;
}
//value.get().addTo(vector);
vector.assign(value.get(), Functions.PLUS);
}
if (vector != null && normPower != PartialVectorMerger.NO_NORMALIZING) {
vector = logNormalize ? vector.logNormalize(normPower) : vector.normalize(normPower);
}
VectorWritable vectorWritable = new VectorWritable(vector);
context.write(key, vectorWritable);
}
@Override
protected void setup(Context context) throws IOException, InterruptedException {
super.setup(context);
Configuration conf = context.getConfiguration();
normPower = conf.getFloat(PartialVectorMerger.NORMALIZATION_POWER, PartialVectorMerger.NO_NORMALIZING);
logNormalize = conf.getBoolean(PartialVectorMerger.LOG_NORMALIZE, false);
}
}