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

Introduction

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

Prototype

public FourthMoment() 

Source Link

Document

Create a FourthMoment instance

Usage

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

static private Object getFourthMoment(final AbstractDataset a) {
    Object obj = a.getStoredValue("moment4");
    if (obj == null) {
        final int is = a.getElementsPerItem();
        final IndexIterator iter = a.getIterator();

        if (is == 1) {
            FourthMoment moment = new FourthMoment();

            while (iter.hasNext()) {
                moment.increment(a.getElementDoubleAbs(iter.index));
            }// w  w  w . ja v a  2  s.  co m
            a.setStoredValue("moment4", moment);
        } else {
            FourthMoment[] moments = new FourthMoment[is];

            for (int j = 0; j < is; j++) {
                moments[j] = new FourthMoment();
            }
            while (iter.hasNext()) {
                for (int j = 0; j < is; j++)
                    moments[j].increment(a.getElementDoubleAbs(iter.index + j));
            }
            a.setStoredValue("moment4", moments);
        }
        obj = a.getStoredValue("moment4");
    }

    return obj;
}

---

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   w  ww  .  j  av a 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);
}

---