com.ibm.bi.dml.runtime.instructions.spark.functions.MatrixVectorBinaryOpPartitionFunction.java Source code

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/**
 * (C) Copyright IBM Corp. 2010, 2015
 *
 * Licensed 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 com.ibm.bi.dml.runtime.instructions.spark.functions;

import java.util.Iterator;

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

import scala.Tuple2;

import com.ibm.bi.dml.lops.BinaryM.VectorType;
import com.ibm.bi.dml.runtime.instructions.spark.data.LazyIterableIterator;
import com.ibm.bi.dml.runtime.instructions.spark.data.PartitionedBroadcastMatrix;
import com.ibm.bi.dml.runtime.matrix.data.MatrixBlock;
import com.ibm.bi.dml.runtime.matrix.data.MatrixIndexes;
import com.ibm.bi.dml.runtime.matrix.operators.BinaryOperator;

public class MatrixVectorBinaryOpPartitionFunction
        implements PairFlatMapFunction<Iterator<Tuple2<MatrixIndexes, MatrixBlock>>, MatrixIndexes, MatrixBlock> {
    private static final long serialVersionUID = 9096091404578628534L;

    private BinaryOperator _op = null;
    private PartitionedBroadcastMatrix _pmV = null;
    private VectorType _vtype = null;

    public MatrixVectorBinaryOpPartitionFunction(BinaryOperator op, PartitionedBroadcastMatrix binput,
            VectorType vtype) {
        _op = op;
        _pmV = binput;
        _vtype = vtype;
    }

    @Override
    public Iterable<Tuple2<MatrixIndexes, MatrixBlock>> call(Iterator<Tuple2<MatrixIndexes, MatrixBlock>> arg0)
            throws Exception {
        return new MapBinaryPartitionIterator(arg0);
    }

    /**
     * Lazy mbinary iterator to prevent materialization of entire partition output in-memory.
     * The implementation via mapPartitions is required to preserve partitioning information,
     * which is important for performance. 
     */
    private class MapBinaryPartitionIterator extends LazyIterableIterator<Tuple2<MatrixIndexes, MatrixBlock>> {
        public MapBinaryPartitionIterator(Iterator<Tuple2<MatrixIndexes, MatrixBlock>> in) {
            super(in);
        }

        @Override
        protected Tuple2<MatrixIndexes, MatrixBlock> computeNext(Tuple2<MatrixIndexes, MatrixBlock> arg)
                throws Exception {
            //unpack partition key-value pairs
            MatrixIndexes ix = arg._1();
            MatrixBlock in1 = arg._2();

            //get the rhs block 
            int rix = (int) ((_vtype == VectorType.COL_VECTOR) ? ix.getRowIndex() : 1);
            int cix = (int) ((_vtype == VectorType.COL_VECTOR) ? 1 : ix.getColumnIndex());
            MatrixBlock in2 = _pmV.getMatrixBlock(rix, cix);

            //execute the binary operation
            MatrixBlock ret = (MatrixBlock) (in1.binaryOperations(_op, in2, new MatrixBlock()));
            return new Tuple2<MatrixIndexes, MatrixBlock>(ix, ret);
        }
    }
}