test/test_adaptsim.cpp

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//
// C++ Implementation: test_romberg
//
// Description: unit tests for romberg integration
//
//
// Author: Roman Geus <geus@maxwell>, (C) 2004
//
// Copyright: See COPYING file that comes with this distribution
//
//

#include <cmath>
#include <tut.h>
#include "rlog/rlog.h"
#include "adaptsim.h"

namespace
{

    double zero(double x) {
        return 0.0;
    }

    double one(double x) {
        return 1.0;
    }

    double ramp(double x) {
        return x;
    }

    double sawtooth(double x) {
        return x-floor(x);
    }

    double recip(double x) {
        return 1.0/x;
    }

    // Example used in Gander Gautschi paper
    struct gg_example {
        gg_example() : num_eval(0)
        {
        }
        double operator()(double x) {
            num_eval ++;
            if (x < 1.0)
                return x + 1.0;
            else if (x < 3.0)
                return 3.0 - x;
            else
                return 2.0;
        }
        int num_eval;
    };

    struct test_data
    {
        test_data()
            : pi(::acos(-1.0)),
              tol(1e-8),
              tol1(1e-11)
        {
        }
        const double pi;
        const double tol;
        const double tol1;
    };

    typedef tut::test_group<test_data> testgroup;
    typedef testgroup::object testobject;
    testgroup group("adaptsim");

    template<>
    template<>
    void testobject::test<1>()
    {
        int info;
        double I = NR::adaptsim(zero, 0.0, 1.0, tol1, info);
        ensure(I == 0.0);
    }

    template<>
    template<>
    void testobject::test<2>()
    {
        int info;
        double I = NR::adaptsim(one, 0.0, 1.0, tol1, info);
        ensure(I == 1.0);
    }

    template<>
    template<>
    void testobject::test<3>()
    {
        int info;
        double I = NR::adaptsim(ramp, 0.0, 1.0, tol1, info);
        ensure(I == 0.5);
    }

    template<>
    template<>
    void testobject::test<4>()
    {
        int info;
        double I = NR::adaptsim(sin, 0.0, pi, tol1, info);
        ensure(fabs(I - 2.0) <= tol);
    }

    template<>
    template<>
    void testobject::test<5>()
    {
        int info;
        double I = NR::adaptsim(sin, 0.0, 2.0*pi, tol1, info);
        ensure(fabs(I) <= tol);
    }

    template<>
    template<>
    void testobject::test<6>()
    {
        int info;
        double I = NR::adaptsim(sawtooth, 0.0, 3.0, tol1, info);
        rDebug("I - 1.5 = %e", I - 1.5);
        ensure(fabs(I - 1.5) <= tol);
    }

    template<>
    template<>
    void testobject::test<7>()
    {
        int info;
        const double left = 1e-5;
        const double right = 1.0;
        double I = NR::adaptsim(recip, left, right, tol1, info);
        double expected = std::log(right) - std::log(left);
        rDebug("I - %e = %e", expected, I - expected);
        ensure(fabs(I - expected) <= tol);
    }

    template<>
    template<>
    void testobject::test<8>()
    {
        int info;
        gg_example f;
        double I = NR::adaptsim(f, 0.0, 5.0, 1e-7, info);
        double expected = 7.5;
        rDebug("I - %e = %e, num_eval=%d", expected, I - expected, f.num_eval);
        ensure(fabs((I - expected)/expected) <= 1e-5);
    }

    template<>
    template<>
    void testobject::test<9>()
    {
        int info;
        double I = NR::adaptsim(sin, pi, 0.0, tol1, info);
        ensure(fabs(I + 2.0) <= tol);
    }

};

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