org.deeplearning4j.spark.impl.common.SplitPartitionsFunction2 Maven / Gradle / Ivy

Show more of this group Show more artifacts with this name
Show all versions of dl4j-spark3_2.12 Show documentation
The newest version!
/*
 *  ******************************************************************************
 *  *
 *  *
 *  * This program and the accompanying materials are made available under the
 *  * terms of the Apache License, Version 2.0 which is available at
 *  * https://www.apache.org/licenses/LICENSE-2.0.
 *  *
 *  *  See the NOTICE file distributed with this work for additional
 *  *  information regarding copyright ownership.
 *  * 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.
 *  *
 *  * SPDX-License-Identifier: Apache-2.0
 *  *****************************************************************************
 */

package org.deeplearning4j.spark.impl.common;

import lombok.AllArgsConstructor;
import org.apache.spark.api.java.function.Function2;
import scala.Tuple2;

import java.util.*;

@AllArgsConstructor
public class SplitPartitionsFunction2
                implements Function2>, Iterator>> {
    private final int splitIndex;
    private final int numSplits;
    private final long baseRngSeed;

    @Override
    public Iterator> call(Integer v1, Iterator> iter) throws Exception {
        long thisRngSeed = baseRngSeed + v1;

        Random r = new Random(thisRngSeed);
        List list = new ArrayList<>();
        for (int i = 0; i < numSplits; i++) {
            list.add(i);
        }

        List> outputList = new ArrayList<>();
        int i = 0;
        while (iter.hasNext()) {
            if (i % numSplits == 0)
                Collections.shuffle(list, r);

            Tuple2 next = iter.next();
            if (list.get(i % numSplits) == splitIndex)
                outputList.add(next);
            i++;
        }

        return outputList.iterator();
    }
}