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Java example source code file (HistogramBin.java)

This example Java source code file (HistogramBin.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

atomicinteger, bigdecimal, builder, data, histogrambin, indarray, jsonignore, linkedhashmap, logger, math, serializable, util

The HistogramBin.java Java example source code

package org.deeplearning4j.ui.weights;

import com.fasterxml.jackson.annotation.JsonIgnore;
import lombok.Data;
import org.nd4j.linalg.api.ndarray.INDArray;
import org.nd4j.linalg.factory.Nd4j;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.Serializable;
import java.math.BigDecimal;
import java.math.RoundingMode;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * @author raver119@gmail.com
 */
@Data
public class HistogramBin implements Serializable {
    private transient INDArray sourceArray;
    private int numberOfBins;
    private int rounds;
    private transient INDArray bins;
    private double max;
    private double min;
    private Map<BigDecimal, AtomicInteger> data = new LinkedHashMap<>();

    private static final Logger log = LoggerFactory.getLogger(HistogramBin.class);

    /**
     * No-Args constructor should be used only for serialization/deserialization purposes.
     * In all other cases please use Histogram.Builder()
     */
    public HistogramBin() {

    }

    /**
     * Builds histogram bin for specified array
     * @param array
     */
    public HistogramBin(INDArray array) {

    }

    @JsonIgnore
    private synchronized void calcHistogram() {
        max = sourceArray.maxNumber().doubleValue();
        min = sourceArray.minNumber().doubleValue();

        bins = Nd4j.create(numberOfBins);
        final double binSize = (max - min) / (numberOfBins - 1);


        data = new LinkedHashMap<>();
        BigDecimal[] keys = new BigDecimal[numberOfBins];

        for (int x = 0; x < numberOfBins; x++) {
            BigDecimal pos = new BigDecimal((min + (x * binSize))).setScale(rounds, BigDecimal.ROUND_CEILING);
            data.put(pos, new AtomicInteger(0));
            keys[x] = pos;
        }

        for (int x = 0; x < sourceArray.length(); x++) {
            double d = sourceArray.getDouble(x);
            int bin = (int) ((d - min) / binSize);

            if (bin < 0) {
                bins.putScalar(0, bins.getDouble(0) + 1);
                data.get(keys[0]).incrementAndGet();
            } else if (bin >= numberOfBins) {
                bins.putScalar(numberOfBins - 1, bins.getDouble(numberOfBins-1) + 1);
                data.get(keys[numberOfBins-1]).incrementAndGet();
              } else {
                bins.putScalar(bin, bins.getDouble(bin) + 1);
                data.get(keys[bin]).incrementAndGet();
            }
        }
    }

    public static class Builder {
        private INDArray source;
        private int binCount;
        private int rounds = 2;

        /**
         * Build Histogram Builder instance for specified array
         * @param array
         */
        public Builder(INDArray array) {
            this.source = array;
        }

        /**
         * Sets number of numbers behind decimal part
         *
         * @param rounds
         * @return
         */
        public Builder setRounding(int rounds) {
            this.rounds = rounds;
            return this;
        }

        /**
         * Specifies number of bins for output histogram
         *
         * @param bins
         * @return
         */
        public Builder setBinCount(int bins) {
            this.binCount = bins;
            return this;
        }

        /**
         * Returns ready-to-use Histogram instance
         * @return
         */
        public HistogramBin build() {
            HistogramBin histogram = new HistogramBin();
            histogram.sourceArray = this.source;
            histogram.numberOfBins = this.binCount;
            histogram.rounds = this.rounds;

            histogram.calcHistogram();

            return histogram;
        }
    }
}

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