org.apache.mahout.vectorizer.pruner.PrunedPartialVectorMergeReducer.java Source code

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Here is the source code for org.apache.mahout.vectorizer.pruner.PrunedPartialVectorMergeReducer.java

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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);
    }
}