Example usage for org.apache.commons.math.analysis.integration LegendreGaussIntegrator LegendreGaussIntegrator

Introduction

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

Prototype

public LegendreGaussIntegrator(final int n, final int defaultMaximalIterationCount)
        throws IllegalArgumentException 

Source Link

Document

Build a Legendre-Gauss integrator.

Usage

From source file:geogebra.kernel.AlgoIntegralDefinite.java

private static double doAdaptiveGaussQuad(RealRootFunction fun, double a, double b) {
    if (++adaptiveGaussQuadCounter > MAX_GAUSS_QUAD_CALLS) {
        return Double.NaN;
    }/*  w  w w.  j  av  a 2 s .  com*/

    // init GaussQuad classes for numerical integration
    if (firstGauss == null) {
        firstGauss = new LegendreGaussIntegrator(FIRST_ORDER, MAX_ITER);
        secondGauss = new LegendreGaussIntegrator(SECOND_ORDER, MAX_ITER);
    }

    double firstSum = 0;
    double secondSum = 0;

    boolean error = false;

    // integrate using gauss quadrature
    try {
        firstSum = firstGauss.integrate(new RealRootAdapter(fun), a, b);
        if (Double.isNaN(firstSum))
            return Double.NaN;
        secondSum = secondGauss.integrate(new RealRootAdapter(fun), a, b);
        if (Double.isNaN(secondSum))
            return Double.NaN;
    } catch (MaxIterationsExceededException e) {
        error = true;
    } catch (ConvergenceException e) {
        error = true;
    } catch (FunctionEvaluationException e) {
        return Double.NaN;
    } catch (IllegalArgumentException e) {
        return Double.NaN;
    }

    //if (!error) Application.debug(a+" "+b+" "+(firstSum - secondSum), Kernel.isEqual(firstSum, secondSum, Kernel.STANDARD_PRECISION) ? 1 : 0);
    //else Application.debug(a+" "+b+" error",1);

    // check if both results are equal
    boolean equal = !error && Kernel.isEqual(firstSum, secondSum, Kernel.STANDARD_PRECISION);

    if (equal) {
        // success              
        return secondSum;
    } else {
        double mid = (a + b) / 2;
        double left = doAdaptiveGaussQuad(fun, a, mid);
        if (Double.isNaN(left))
            return Double.NaN;
        else
            return left + doAdaptiveGaussQuad(fun, mid, b);
    }
}

---

From source file:geogebra.common.kernel.cas.AlgoIntegralDefinite.java

private static double doAdaptiveGaussQuad(RealRootFunction fun, double a, double b) {
    if (++adaptiveGaussQuadCounter > MAX_GAUSS_QUAD_CALLS) {
        return Double.NaN;
    }//from   www .j av  a 2 s.c o  m

    // init GaussQuad classes for numerical integration
    if (firstGauss == null) {
        firstGauss = new LegendreGaussIntegrator(FIRST_ORDER, MAX_ITER);
        secondGauss = new LegendreGaussIntegrator(SECOND_ORDER, MAX_ITER);
    }

    double firstSum = 0;
    double secondSum = 0;

    boolean error = false;

    // integrate using gauss quadrature
    try {
        firstSum = firstGauss.integrate((new RealRootAdapter(fun)), a, b);
        if (Double.isNaN(firstSum))
            return Double.NaN;
        secondSum = secondGauss.integrate((new RealRootAdapter(fun)), a, b);
        if (Double.isNaN(secondSum))
            return Double.NaN;
    } catch (MaxIterationsExceededException e) {
        error = true;
    } catch (ConvergenceException e) {
        error = true;
    } catch (FunctionEvaluationException e) {
        return Double.NaN;
    } catch (IllegalArgumentException e) {
        return Double.NaN;
    }

    // if (!error) Application.debug(a+" "+b+" "+(firstSum - secondSum),
    // Kernel.isEqual(firstSum, secondSum, Kernel.STANDARD_PRECISION) ? 1 :
    // 0);
    // else Application.debug(a+" "+b+" error",1);

    // check if both results are equal
    boolean equal = !error && Kernel.isEqual(firstSum, secondSum, Kernel.STANDARD_PRECISION);

    if (equal) {
        // success
        return secondSum;
    }
    double mid = (a + b) / 2;
    double left = doAdaptiveGaussQuad(fun, a, mid);
    if (Double.isNaN(left)) {
        return Double.NaN;
    }
    return left + doAdaptiveGaussQuad(fun, mid, b);
}

---