Example usage for org.apache.commons.math3.fitting HarmonicCurveFitter fit

Introduction

In this page you can find the example usage for org.apache.commons.math3.fitting HarmonicCurveFitter fit.

Prototype

public double[] fit(Collection<WeightedObservedPoint> points) 

Source Link

Document

Fits a curve.

Usage

From source file:org.apache.solr.client.solrj.io.eval.HarmonicFitEvaluator.java

@Override
public Object doWork(Object... objects) throws IOException {

    if (objects.length > 3) {
        throw new IOException("harmonicFit function takes a maximum of 2 arguments.");
    }// w w  w.  j  a va  2  s. com

    Object first = objects[0];

    double[] x = null;
    double[] y = null;

    if (objects.length == 1) {
        //Only the y values passed

        y = ((List) first).stream().mapToDouble(value -> ((BigDecimal) value).doubleValue()).toArray();
        x = new double[y.length];
        for (int i = 0; i < y.length; i++) {
            x[i] = i;
        }

    } else if (objects.length == 2) {
        // x and y passed
        Object second = objects[1];
        x = ((List) first).stream().mapToDouble(value -> ((BigDecimal) value).doubleValue()).toArray();
        y = ((List) second).stream().mapToDouble(value -> ((BigDecimal) value).doubleValue()).toArray();

    }

    HarmonicCurveFitter curveFitter = HarmonicCurveFitter.create();

    WeightedObservedPoints points = new WeightedObservedPoints();
    for (int i = 0; i < x.length; i++) {
        points.add(x[i], y[i]);
    }

    double[] coef = curveFitter.fit(points.toList());
    HarmonicOscillator pf = new HarmonicOscillator(coef[0], coef[1], coef[2]);

    List list = new ArrayList();
    for (double xvalue : x) {
        double yvalue = pf.value(xvalue);
        list.add(yvalue);
    }

    return list;
}

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