Examples with AkimaSplineInterpolator org.apache.commons.math3.analysis.interpolation.AkimaSplineInterpolator used on opensource projects

Example 1 with AkimaSplineInterpolator

use of org.apache.commons.math3.analysis.interpolation.AkimaSplineInterpolator in project mafscaling by vimsh.

the class BilinearInterpolator method interpolate.

/**
 * Method returns an interpolated/extrapolated value, based on
 * @param x, array of x values
 * @param y, array of y values
 * @param xi, is x value you want to interpolate at
 * @param type, interpolation method type
 * @return interpolated value
 * @throws Exception
 */
public static double interpolate(double[] x, double[] y, double xi, InterpolatorType type) throws Exception {
    UnivariateInterpolator interpolator = null;
    switch(type) {
        case AkimaCubicSpline:
            interpolator = new AkimaSplineInterpolator();
            break;
        case Linear:
            interpolator = new LinearInterpolator();
            break;
        case Regression:
            interpolator = new LoessInterpolator();
            break;
        case CubicSpline:
            interpolator = new SplineInterpolator();
            break;
        default:
            throw new Exception("Invalid interpolator type for this function");
    }
    UnivariateFunction function = interpolator.interpolate(x, y);
    PolynomialFunction[] polynomials = ((PolynomialSplineFunction) function).getPolynomials();
    if (xi > x[x.length - 1])
        return polynomials[polynomials.length - 1].value(xi - x[x.length - 2]);
    if (xi < x[0])
        return polynomials[0].value(xi - x[0]);
    return function.value(xi);
}