org.apache.sysml.runtime.instructions.spark.functions.ExtractGroupNWeights.java Source code

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Here is the source code for org.apache.sysml.runtime.instructions.spark.functions.ExtractGroupNWeights.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.apache.sysml.runtime.instructions.spark.functions;

import java.util.ArrayList;
import java.util.Iterator;

import org.apache.spark.api.java.function.PairFlatMapFunction;

import scala.Tuple2;

import org.apache.sysml.runtime.matrix.data.MatrixBlock;
import org.apache.sysml.runtime.matrix.data.MatrixIndexes;
import org.apache.sysml.runtime.matrix.data.WeightedCell;
import org.apache.sysml.runtime.util.UtilFunctions;

public class ExtractGroupNWeights implements
        PairFlatMapFunction<Tuple2<MatrixIndexes, Tuple2<Tuple2<MatrixBlock, MatrixBlock>, MatrixBlock>>, MatrixIndexes, WeightedCell> {

    private static final long serialVersionUID = -188180042997588072L;

    @Override
    public Iterator<Tuple2<MatrixIndexes, WeightedCell>> call(
            Tuple2<MatrixIndexes, Tuple2<Tuple2<MatrixBlock, MatrixBlock>, MatrixBlock>> arg) throws Exception {
        MatrixBlock group = arg._2._1._1;
        MatrixBlock target = arg._2._1._2;
        MatrixBlock weight = arg._2._2;

        //sanity check matching block dimensions
        if (group.getNumRows() != target.getNumRows() || group.getNumRows() != target.getNumRows()) {
            throw new Exception("The blocksize for group/target/weight blocks are mismatched: " + group.getNumRows()
                    + ", " + target.getNumRows() + ", " + weight.getNumRows());
        }

        //output weighted cells      
        ArrayList<Tuple2<MatrixIndexes, WeightedCell>> groupValuePairs = new ArrayList<>();
        for (int i = 0; i < group.getNumRows(); i++) {
            WeightedCell weightedCell = new WeightedCell();
            weightedCell.setValue(target.quickGetValue(i, 0));
            weightedCell.setWeight(weight.quickGetValue(i, 0));
            long groupVal = UtilFunctions.toLong(group.quickGetValue(i, 0));
            if (groupVal < 1) {
                throw new Exception("Expected group values to be greater than equal to 1 but found " + groupVal);
            }
            MatrixIndexes ix = new MatrixIndexes(groupVal, 1);
            groupValuePairs.add(new Tuple2<>(ix, weightedCell));
        }

        return groupValuePairs.iterator();
    }
}