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Java example source code file (NegativeHolder.java)

This example Java source code file (NegativeHolder.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

atomicboolean, floatbuffer, getter, indarray, negativeholder, serializable, string, vocabcache

The NegativeHolder.java Java example source code

package org.deeplearning4j.spark.models.embeddings.word2vec;

import lombok.Getter;
import lombok.NonNull;
import org.deeplearning4j.models.word2vec.VocabWord;
import org.deeplearning4j.models.word2vec.wordstore.VocabCache;
import org.nd4j.linalg.api.buffer.FloatBuffer;
import org.nd4j.linalg.api.ndarray.INDArray;
import org.nd4j.linalg.factory.Nd4j;

import java.io.Serializable;
import java.util.concurrent.atomic.AtomicBoolean;

 * Simple singleton holder class for w2v negative sampling, to avoid syn1Neg creation for each spark node
 * @author raver119@gmail.com
public class NegativeHolder implements Serializable {
    private static NegativeHolder ourInstance = new NegativeHolder();

    public static NegativeHolder getInstance() {
        return ourInstance;

    @Getter private volatile INDArray syn1Neg;
    @Getter private volatile INDArray table;

    private transient AtomicBoolean wasInit = new AtomicBoolean(false);
    private transient VocabCache<VocabWord> vocab;

    private NegativeHolder() {


    public synchronized void initHolder(@NonNull VocabCache<VocabWord> vocabCache, double[] expTable, int layerSize) {
         if (!wasInit.get()) {
            this.vocab = vocabCache;
            this.syn1Neg = Nd4j.zeros(vocabCache.numWords(), layerSize);
            makeTable(Math.max(expTable.length, 100000), 0.75);
    protected void makeTable(int tableSize,double power) {
        int vocabSize = vocab.numWords();
        table = Nd4j.create(new FloatBuffer(tableSize));
        double trainWordsPow = 0.0;
        for(String word : vocab.words()) {
            trainWordsPow += Math.pow(vocab.wordFrequency(word), power);

        int wordIdx = 0;
        String word = vocab.wordAtIndex(wordIdx);
        double d1 = Math.pow(vocab.wordFrequency(word),power) / trainWordsPow;
        for(int i = 0; i < tableSize; i++) {
            double mul = i * 1.0 / (double) tableSize;
            if(mul > d1) {
                if( wordIdx < vocabSize-1 )
                word = vocab.wordAtIndex(wordIdx);
                String wordAtIndex = vocab.wordAtIndex(wordIdx);
                if(word == null)
                d1 += Math.pow(vocab.wordFrequency(wordAtIndex),power) / trainWordsPow;


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