Example usage for org.apache.commons.math3.analysis.interpolation AkimaSplineInterpolator interpolate

Introduction

In this page you can find the example usage for org.apache.commons.math3.analysis.interpolation AkimaSplineInterpolator interpolate.

Prototype

public PolynomialSplineFunction interpolate(double[] xvals, double[] yvals)
        throws DimensionMismatchException, NumberIsTooSmallException, NonMonotonicSequenceException 

Source Link

Document

Computes an interpolating function for the data set.

Usage

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

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

    Object first = objects[0];//from w w w  .  java  2  s  .c  o  m

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

    if (objects.length == 1) {
        //Only the y values passed
        y = ((List) first).stream().mapToDouble(value -> ((Number) value).doubleValue()).toArray();
        x = new double[y.length];
        for (int i = 0; i < y.length; i++) {
            x[i] = i;
        }
    } else if (objects.length == 2) {
        Object second = objects[1];
        x = ((List) first).stream().mapToDouble(value -> ((Number) value).doubleValue()).toArray();
        y = ((List) second).stream().mapToDouble(value -> ((Number) value).doubleValue()).toArray();
    }

    AkimaSplineInterpolator interpolator = new AkimaSplineInterpolator();
    PolynomialSplineFunction spline = interpolator.interpolate(x, y);

    List<Number> list = new ArrayList();
    for (double xvalue : x) {
        list.add(spline.value(xvalue));
    }

    VectorFunction vec = new VectorFunction(spline, list);
    vec.addToContext("x", x);
    vec.addToContext("y", y);

    return vec;
}

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