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

Java example source code file (MnistDataFetcher.java)

This example Java source code file (MnistDataFetcher.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

dataset, file, indarray, ioexception, mnist_root, mnistdatafetcher, mnistmanager, num_examples, num_examples_test, override, random, shuffle, string, temp_root, util

The MnistDataFetcher.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.datasets.fetchers;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Random;

import org.apache.commons.io.FileUtils;
import org.apache.commons.io.FilenameUtils;
import org.deeplearning4j.base.MnistFetcher;
import org.deeplearning4j.datasets.mnist.MnistManager;
import org.deeplearning4j.util.MathUtils;
import org.nd4j.linalg.api.ndarray.INDArray;
import org.nd4j.linalg.dataset.DataSet;
import org.nd4j.linalg.factory.Nd4j;


/**
 * Data fetcher for the MNIST dataset
 * @author Adam Gibson
 *
 */
public class MnistDataFetcher extends BaseDataFetcher {
    public static final int NUM_EXAMPLES = 60000;
    public static final int NUM_EXAMPLES_TEST = 10000;
    protected static final String TEMP_ROOT = System.getProperty("user.home");
    protected static final String MNIST_ROOT = TEMP_ROOT + File.separator + "MNIST" + File.separator;

    protected transient MnistManager man;
    protected boolean binarize = true;
    protected boolean train;
    protected int[] order;
    protected Random rng;
    protected boolean shuffle;


    /**
     * Constructor telling whether to binarize the dataset or not
     * @param binarize whether to binarize the dataset or not
     * @throws IOException
     */
    public MnistDataFetcher(boolean binarize) throws IOException {
        this(binarize,true,true,System.currentTimeMillis());
    }

    public MnistDataFetcher(boolean binarize, boolean train, boolean shuffle, long rngSeed) throws IOException {
        if(!mnistExists()) {
            new MnistFetcher().downloadAndUntar();
        }
        String images;
        String labels;
        if(train){
            images = MNIST_ROOT + MnistFetcher.trainingFilesFilename_unzipped;
            labels = MNIST_ROOT + MnistFetcher.trainingFileLabelsFilename_unzipped;
            totalExamples = NUM_EXAMPLES;
        } else {
            images = MNIST_ROOT + MnistFetcher.testFilesFilename_unzipped;
            labels = MNIST_ROOT + MnistFetcher.testFileLabelsFilename_unzipped;
            totalExamples = NUM_EXAMPLES_TEST;
        }

        try {
            man = new MnistManager(images, labels, train);
        }catch(Exception e) {
            FileUtils.deleteDirectory(new File(MNIST_ROOT));
            new MnistFetcher().downloadAndUntar();
            man = new MnistManager(images, labels, train);
        }

        numOutcomes = 10;
        this.binarize = binarize;
        cursor = 0;
        inputColumns = man.getImages().getEntryLength();
        this.train = train;
        this.shuffle = shuffle;

        if(train){
            order = new int[NUM_EXAMPLES];
        } else {
            order = new int[NUM_EXAMPLES_TEST];
        }
        for( int i=0; i<order.length; i++ ) order[i] = i;
        rng = new Random(rngSeed);
        reset();    //Shuffle order
    }

    private boolean mnistExists(){
        //Check 4 files:
        File f = new File(MNIST_ROOT,MnistFetcher.trainingFilesFilename_unzipped);
        if(!f.exists()) return false;
        f = new File(MNIST_ROOT,MnistFetcher.trainingFileLabelsFilename_unzipped);
        if(!f.exists()) return false;
        f = new File(MNIST_ROOT,MnistFetcher.testFilesFilename_unzipped);
        if(!f.exists()) return false;
        f = new File(MNIST_ROOT,MnistFetcher.testFileLabelsFilename_unzipped);
        if(!f.exists()) return false;
        return true;
    }

    public MnistDataFetcher() throws IOException {
        this(true);
    }

    @Override
    public void fetch(int numExamples) {
        if(!hasMore()) {
            throw new IllegalStateException("Unable to getFromOrigin more; there are no more images");
        }


        float[][] featureData = new float[numExamples][0];
        float[][] labelData = new float[numExamples][0];

        int actualExamples = 0;
        for( int i=0; i<numExamples; i++, cursor++ ){
            if(!hasMore()) break;

            byte[] img = man.readImageUnsafe(order[cursor]);
            int label = man.readLabel(order[cursor]);

            float[] featureVec = new float[img.length];
            featureData[actualExamples] = featureVec;
            labelData[actualExamples] = new float[10];
            labelData[actualExamples][label] = 1.0f;

            for( int j=0; j<img.length; j++ ){
                float v = ((int)img[j]) & 0xFF; //byte is loaded as signed -> convert to unsigned
                if(binarize){
                    if(v > 30.0f) featureVec[j] = 1.0f;
                    else featureVec[j] = 0.0f;
                } else {
                    featureVec[j] = v/255.0f;
                }
            }

            actualExamples++;
        }

        if(actualExamples < numExamples){
            featureData = Arrays.copyOfRange(featureData,0,actualExamples);
            labelData = Arrays.copyOfRange(labelData,0,actualExamples);
        }

        INDArray features = Nd4j.create(featureData);
        INDArray labels = Nd4j.create(labelData);
        curr = new DataSet(features,labels);
    }

    @Override
    public void reset() {
        cursor = 0;
        curr = null;
        if(shuffle) MathUtils.shuffleArray(order, rng);
    }

    @Override
    public DataSet next() {
        DataSet next = super.next();
        return next;
    }

}

Other Java examples (source code examples)

Here is a short list of links related to this Java MnistDataFetcher.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.