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/*
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* * 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
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* * SPDX-License-Identifier: Apache-2.0
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*/
package org.deeplearning4j.spark.impl.common;
import lombok.AllArgsConstructor;
import org.apache.spark.api.java.function.Function2;
import java.util.*;
@AllArgsConstructor
public class SplitPartitionsFunction 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);
T next = iter.next();
if (list.get(i % numSplits) == splitIndex)
outputList.add(next);
i++;
}
return outputList.iterator();
}
}