org.swjtu.helloworldcn.APCMatrixInputReducer.java Source code

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Here is the source code for org.swjtu.helloworldcn.APCMatrixInputReducer.java

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/**
 * 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.swjtu.helloworldcn;

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.mahout.math.RandomAccessSparseVector;
import org.apache.mahout.math.SequentialAccessSparseVector;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @author Tang
 * @since 2012-3
 * ??Reducer
 */
public class APCMatrixInputReducer
        extends Reducer<IntWritable, APCMatrixEntryWritable, IntWritable, APCRowVectorWritable> {

    private static final Logger log = LoggerFactory.getLogger(APCMatrixInputReducer.class);
    private Double preference = null;

    @Override
    protected void reduce(IntWritable row, Iterable<APCMatrixEntryWritable> values, Context context)
            throws IOException, InterruptedException {
        int size = context.getConfiguration().getInt(APCMatrixInputJob.MATRIX_DIMENSIONS, Integer.MAX_VALUE);
        RandomAccessSparseVector outS = new RandomAccessSparseVector(size, 100);
        RandomAccessSparseVector outA = new RandomAccessSparseVector(size, 100);
        RandomAccessSparseVector outR = new RandomAccessSparseVector(size, 100);

        Configuration conf = context.getConfiguration();
        if (preference == null) {
            preference = Double.parseDouble(conf.get(APCMatrixInputJob.TEMPORARY_SAVE_PREFERENCE));
        }

        //System.out.println("pian du"+preference);

        for (APCMatrixEntryWritable element : values) {
            outS.setQuick(element.getCol(), element.getValS());
            outA.setQuick(element.getCol(), 0.0);
            outR.setQuick(element.getCol(), 0.0);

        }
        //Place preferences on the diagonal of S
        outS.setQuick(row.get(), preference);

        SequentialAccessSparseVector outputS = new SequentialAccessSparseVector(outS);
        SequentialAccessSparseVector outputA = new SequentialAccessSparseVector(outA);
        SequentialAccessSparseVector outputR = new SequentialAccessSparseVector(outR);
        APCRowVectorWritable rowVectorWritable = new APCRowVectorWritable(outputA, outputR, outputS);
        //System.out.println(outputS);
        context.write(row, rowVectorWritable);
    }
}