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

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

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

import scala.Tuple2;

import org.apache.sysml.lops.Checkpoint;
import org.apache.sysml.runtime.instructions.spark.data.LazyIterableIterator;
import org.apache.sysml.runtime.matrix.data.MatrixBlock;
import org.apache.sysml.runtime.matrix.data.MatrixIndexes;
import org.apache.sysml.runtime.matrix.data.SparseBlock;

/**
 * General purpose copy function for binary block rdds. This function can be used in
 * mapToPair (copy matrix indexes and blocks). It supports both deep and shallow copies 
 * of key/value pairs.
 * 
 */
public class CopyBlockPairFunction
        implements PairFlatMapFunction<Iterator<Tuple2<MatrixIndexes, MatrixBlock>>, MatrixIndexes, MatrixBlock> {
    private static final long serialVersionUID = -196553327495233360L;

    private boolean _deepCopy = true;

    public CopyBlockPairFunction() {
        this(true);
    }

    public CopyBlockPairFunction(boolean deepCopy) {
        _deepCopy = deepCopy;
    }

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

    private class CopyBlockPairIterator extends LazyIterableIterator<Tuple2<MatrixIndexes, MatrixBlock>> {
        public CopyBlockPairIterator(Iterator<Tuple2<MatrixIndexes, MatrixBlock>> iter) {
            super(iter);
        }

        @Override
        protected Tuple2<MatrixIndexes, MatrixBlock> computeNext(Tuple2<MatrixIndexes, MatrixBlock> arg)
                throws Exception {
            if (_deepCopy) {
                MatrixIndexes ix = new MatrixIndexes(arg._1());
                MatrixBlock block = null;
                //always create deep copies in more memory-efficient CSR representation 
                //if block is already in sparse format         
                if (Checkpoint.CHECKPOINT_SPARSE_CSR && arg._2.isInSparseFormat())
                    block = new MatrixBlock(arg._2, SparseBlock.Type.CSR, true);
                else
                    block = new MatrixBlock(arg._2());
                return new Tuple2<>(ix, block);
            } else {
                return arg;
            }
        }
    }
}