IntegratorGK.cpp

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//  ************************************************************************************************
//
//  BornAgain: simulate and fit reflection and scattering
//
//! @file      Base/Math/IntegratorGK.cpp
//! @brief     Implements classes RealIntegrator, ComplexIntegrator.
//!
//! @homepage  http://www.bornagainproject.org
//! @license   GNU General Public License v3 or higher (see COPYING)
//! @copyright Forschungszentrum Jülich GmbH 2018
//! @authors   Scientific Computing Group at MLZ (see CITATION, AUTHORS)
//
//  ************************************************************************************************
 
#include "Base/Math/IntegratorGK.h"
 
RealIntegrator::RealIntegrator()
    : m_gsl_f{m_Cfunction, nullptr}
    , m_workspace{gsl_integration_workspace_alloc(200)}
{
}
 
RealIntegrator::~RealIntegrator()
{
    gsl_integration_workspace_free(m_workspace);
}
 
double RealIntegrator::integrate(const std::function<double(double)>& f, double lmin, double lmax)
{
    m_gsl_f.params = (void*)&f;
    double result, error;
    gsl_integration_qag(&m_gsl_f, lmin, lmax, 1e-9, 1e-7, 200, 3, m_workspace, &result, &error);
    // TODO check error
    return result;
}
 
complex_t ComplexIntegrator::integrate(const std::function<complex_t(double)>& f, double lmin,
                                       double lmax)
{
    return {realPart.integrate([f](double x) { return f(x).real(); }, lmin, lmax),
            imagPart.integrate([f](double x) { return f(x).imag(); }, lmin, lmax)};
}