home | career | drupal | java | mac | mysql | perl | scala | uml | unix  

Java example source code file (RDDMiniBatches.java)

This example Java source code file (RDDMiniBatches.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

arraylist, dataset, exception, flatmapfunction, iterable, javardd, list, minibatchfunction, override, rddminibatches, serializable, util

The RDDMiniBatches.java Java example source code

/*
 *
 *  * Copyright 2015 Skymind,Inc.
 *  *
 *  *    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 org.deeplearning4j.spark.canova;

import org.apache.spark.api.java.JavaRDD;
import org.apache.spark.api.java.function.FlatMapFunction;
import org.nd4j.linalg.dataset.DataSet;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

/**
 * RDD mini batch partitioning
 * @author Adam Gibson
 */
public class RDDMiniBatches  implements Serializable {
    private int miniBatches = 10;
    private JavaRDD<DataSet> toSplitJava;

    public RDDMiniBatches(int miniBatches, JavaRDD<DataSet> toSplit) {
        this.miniBatches = miniBatches;
        this.toSplitJava = toSplit;
    }

    public JavaRDD<DataSet> miniBatchesJava() {
        //need a new mapping function, doesn't handle mini batches properly
        return toSplitJava.mapPartitions(new MiniBatchFunction(miniBatches));
    }


    public static class MiniBatchFunction implements FlatMapFunction<Iterator {
        private int batchSize = 10;

        public MiniBatchFunction(int batchSize) {
            this.batchSize = batchSize;
        }

        @Override
        public Iterable<DataSet> call(Iterator dataSetIterator) throws Exception {
            List<DataSet> ret = new ArrayList<>();
            List<DataSet> temp = new ArrayList<>();
            while (dataSetIterator.hasNext()) {
                temp.add(dataSetIterator.next().copy());
                if (temp.size() == batchSize) {
                    ret.add(DataSet.merge(temp));
                    temp.clear();
                }
            }

            //edge cases with map partitions where one will be left over.
            //this is due to race conditions.
            if(temp.size() > 1)
                ret.add(DataSet.merge(temp));

            return ret;
        }

    }


}

Other Java examples (source code examples)

Here is a short list of links related to this Java RDDMiniBatches.java source code file:



my book on functional programming

 

new blog posts

 

Copyright 1998-2019 Alvin Alexander, alvinalexander.com
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.