Example usage for org.apache.commons.math.analysis UnivariateRealSolver solve

Introduction

In this page you can find the example usage for org.apache.commons.math.analysis UnivariateRealSolver solve.

Prototype

double solve(double min, double max) throws ConvergenceException, FunctionEvaluationException;

Source Link

Document

Solve for a zero root in the given interval.

Usage

From source file:desmoj.core.dist.ContDistCustom.java

/**
 * Returns the next sample from this distribution. The value depends upon
 * the seed, the number of values taken from the stream by using this method
 * before and the alpha and beta parameters specified for this distribution.
 * //w  w  w  . j  ava  2s .  com
 * @return Double : The next gamma distributed sample from this
 *         distribution.
 */
public Double sample() {

    double newSample; //

    incrementObservations(); // increase count of samples

    randomNumber = randomGenerator.nextDouble();
    if (isAntithetic()) {
        randomNumber = 1 - randomNumber;

    }

    Function functiontosolve = new Function() {

        public double value(double x) {

            return distFunction.value(x) - randomNumber;
            // Decrease input function by randomNumber to make the desired
            // sample be at a zero root.
        }

        public String getDescription() {
            return null;
        }
    };

    UnivariateRealSolver solver = new BisectionSolver(functiontosolve);
    try {
        newSample = solver.solve(lowerBound, upperBound); // Finding zero
        // root

    } catch (Exception e) {
        sendWarning("Failed to find sample, returning -1",
                "CustomContDist : " + getName() + " Method: sample()",
                "The solver could not deal with the distribution function specified.",
                "Make sure the CustomFunction this Distribution is using is a proper "
                        + "distribution function and the upper and lower bounds are set accordingly");
        newSample = -1;
    }
    if (this.currentlySendTraceNotes())
        this.traceLastSample(Double.toString(newSample));
    return newSample;

}

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