Example usage for org.apache.commons.math.stat.descriptive.moment Skewness Skewness

Introduction

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

Prototype

public Skewness(Skewness original) 

Source Link

Document

Copy constructor, creates a new Skewness identical to the original

Usage

From source file:uk.ac.diamond.scisoft.analysis.dataset.Stats.java

/**
 * @param a dataset// w  w  w.ja  va  2s.  com
 * @return skewness
 */
public static Object skewness(final AbstractDataset a) {
    Object m = getFourthMoment(a);
    if (m instanceof FourthMoment) {
        return Double.valueOf((new Skewness((FourthMoment) m)).getResult());
    }

    FourthMoment[] mos = (FourthMoment[]) m;
    final int is = mos.length;
    double[] skews = new double[is];
    for (int j = 0; j < is; j++) {
        skews[j] = (new Skewness(mos[j])).getResult();
    }
    return skews;
}

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From source file:uk.ac.diamond.scisoft.analysis.dataset.Stats.java

static private void calculateHigherMoments(final AbstractDataset a, int axis) {
    int rank = a.getRank();

    int[] oshape = a.getShape();
    int alen = oshape[axis];
    oshape[axis] = 1;//from ww  w . j a  va  2 s.c  o  m

    int[] nshape = AbstractDataset.squeezeShape(oshape, false);
    DoubleDataset sk = new DoubleDataset(nshape);
    DoubleDataset ku = new DoubleDataset(nshape);

    IndexIterator qiter = sk.getIterator(true);
    int[] qpos = qiter.getPos();
    int[] spos = oshape;

    while (qiter.hasNext()) {
        int i = 0;
        for (; i < axis; i++) {
            spos[i] = qpos[i];
        }
        spos[i++] = 0;
        for (; i < rank; i++) {
            spos[i] = qpos[i - 1];
        }

        FourthMoment moment = new FourthMoment();
        for (int j = 0; j < alen; j++) {
            spos[axis] = j;
            final double val = a.getDouble(spos);
            if (Double.isInfinite(val) || Double.isNaN(val))
                continue;

            moment.increment(val);
        }
        sk.set((new Skewness(moment)).getResult(), spos);
        ku.set((new Kurtosis(moment)).getResult(), spos);
    }
    a.setStoredValue("skewness-" + axis, sk);
    a.setStoredValue("kurtosis-" + axis, ku);
}

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