Example usage for org.apache.commons.math.stat.descriptive.summary SumOfSquares SumOfSquares

Introduction

In this page you can find the example usage for org.apache.commons.math.stat.descriptive.summary SumOfSquares SumOfSquares.

Prototype

public SumOfSquares() 

Source Link

Document

Create a SumOfSquares instance

Usage

From source file:net.sf.jdmf.util.MathCalculator.java

/**
 * Calculates the distance between two points in a nD space (assumes that
 * n = firstPoint.size() = secondPoint.size()). 
 * /*from   w w w.  java 2 s .  co  m*/
 * @param firstPoint the first point
 * @param secondPoint the second point
 * @return the distance between both points
 */
public Double calculateDistance(Vector<Double> firstPoint, Vector<Double> secondPoint) {
    SumOfSquares sumOfSquares = new SumOfSquares();

    for (int i = 0; i < firstPoint.size(); ++i) {
        sumOfSquares.increment(secondPoint.get(i) - firstPoint.get(i));
    }

    return Math.sqrt(sumOfSquares.getResult());
}

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From source file:org.NooLab.math3.stat.inference.OneWayAnova.java

/**
 * This method actually does the calculations (except P-value).
 *
 * @param categoryData <code>Collection</code> of <code>double[]</code>
 * arrays each containing data for one category
 * @return computed AnovaStats//from w  w w.ja v a2s  .c  o  m
 * @throws NullArgumentException if <code>categoryData</code> is <code>null</code>
 * @throws DimensionMismatchException if the length of the <code>categoryData</code>
 * array is less than 2 or a contained <code>double[]</code> array does not contain
 * at least two values
 */
private AnovaStats anovaStats(final Collection<double[]> categoryData)
        throws NullArgumentException, DimensionMismatchException {

    if (categoryData == null) {
        throw new NullArgumentException();
    }

    // check if we have enough categories
    if (categoryData.size() < 2) {
        throw new DimensionMismatchException(LocalizedFormats.TWO_OR_MORE_CATEGORIES_REQUIRED,
                categoryData.size(), 2);
    }

    // check if each category has enough data and all is double[]
    for (double[] array : categoryData) {
        if (array.length <= 1) {
            throw new DimensionMismatchException(LocalizedFormats.TWO_OR_MORE_VALUES_IN_CATEGORY_REQUIRED,
                    array.length, 2);
        }
    }

    int dfwg = 0;
    double sswg = 0;
    Sum totsum = new Sum();
    SumOfSquares totsumsq = new SumOfSquares();
    int totnum = 0;

    for (double[] data : categoryData) {

        Sum sum = new Sum();
        SumOfSquares sumsq = new SumOfSquares();
        int num = 0;

        for (int i = 0; i < data.length; i++) {
            double val = data[i];

            // within category
            num++;
            sum.increment(val);
            sumsq.increment(val);

            // for all categories
            totnum++;
            totsum.increment(val);
            totsumsq.increment(val);
        }
        dfwg += num - 1;
        double ss = sumsq.getResult() - sum.getResult() * sum.getResult() / num;
        sswg += ss;
    }
    double sst = totsumsq.getResult() - totsum.getResult() * totsum.getResult() / totnum;
    double ssbg = sst - sswg;
    int dfbg = categoryData.size() - 1;
    double msbg = ssbg / dfbg;
    double mswg = sswg / dfwg;
    double F = msbg / mswg;

    return new AnovaStats(dfbg, dfwg, F);
}

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