Example usage for org.apache.commons.math3.analysis.solvers BracketingNthOrderBrentSolver BracketingNthOrderBrentSolver

Introduction

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

Prototype

public BracketingNthOrderBrentSolver(final double relativeAccuracy, final double absoluteAccuracy,
        final int maximalOrder) throws NumberIsTooSmallException 

Source Link

Document

Construct a solver.

Usage

From source file:org.micromanager.asidispim.fit.Fitter.java

/**
 * Finds the x value corresponding to the maximum function value within the 
 * range of the provided data set./* www.j a  v a  2s.co  m*/
 * 
 * @param type one of the Fitter.FunctionType predefined functions
 * @param parms parameters describing the function.  These need to match the
 *             selected function or an IllegalArgumentEception will be thrown
 * @param data JFreeChart series, used to bracket the range in which the 
 *             maximum will be found
 * 
 * @return x value corresponding to the maximum function value
 */
public static double getXofMaxY(XYSeries data, FunctionType type, double[] parms) {
    double xAtMax = 0.0;
    double minX = data.getMinX();
    double maxX = data.getMaxX();
    switch (type) {
    case NoFit:
        //  find the position in data with the highest y value
        double highestScore = data.getY(0).doubleValue();
        int highestIndex = 0;
        for (int i = 1; i < data.getItemCount(); i++) {
            double newVal = data.getY(i).doubleValue();
            if (newVal > highestScore) {
                highestScore = newVal;
                highestIndex = i;
            }
        }
        return data.getX(highestIndex).doubleValue();
    case Pol1:
    case Pol2:
    case Pol3:
        checkParms(type, parms);
        PolynomialFunction derivativePolFunction = (new PolynomialFunction(parms)).polynomialDerivative();

        final double relativeAccuracy = 1.0e-12;
        final double absoluteAccuracy = 1.0e-8;
        final int maxOrder = 5;
        UnivariateSolver solver = new BracketingNthOrderBrentSolver(relativeAccuracy, absoluteAccuracy,
                maxOrder);
        xAtMax = solver.solve(100, derivativePolFunction, minX, maxX);
        break;
    case Gaussian:
        // for a Gaussian we can take the mean and be sure it is the maximum
        // note that this may be outside our range of X values, but 
        // this will be caught by our sanity checks below
        xAtMax = parms[1];
    }

    // sanity checks
    if (xAtMax > maxX)
        xAtMax = maxX;
    if (xAtMax < minX)
        xAtMax = minX;

    return xAtMax;
}

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