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

Introduction

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

Prototype

AkimaSplineInterpolator

Source Link

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. j av  a 2  s. com*/

    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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From source file:org.meteoinfo.math.interpolate.InterpUtil.java

/**
 * Make interpolation function/*from   www  .j  a  v  a2 s . co  m*/
 * @param x X data
 * @param y Y data
 * @param kind Specifies the kind of interpolation as a string (linear, 'spline').
 * @return Interpolation function
 */
public static UnivariateFunction getInterpFunc(Array x, Array y, String kind) {
    double[] xd = (double[]) ArrayUtil.copyToNDJavaArray(x);
    double[] yd = (double[]) ArrayUtil.copyToNDJavaArray(y);
    UnivariateInterpolator li;
    switch (kind) {
    case "spline":
    case "cubic":
        li = new SplineInterpolator();
        break;
    case "akima":
        li = new AkimaSplineInterpolator();
        break;
    case "divided":
        li = new DividedDifferenceInterpolator();
        break;
    case "loess":
        li = new LoessInterpolator();
        break;
    case "neville":
        li = new NevilleInterpolator();
        break;
    default:
        li = new LinearInterpolator();
        break;
    }
    UnivariateFunction psf = li.interpolate(xd, yd);

    return psf;
}

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