branin.cpp

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#include <boost/math/constants/constants.hpp>
#include <cmath>
#include <string>

#include "../types.h"
#include "base.h"
#include "branin.h"

namespace pagmo { namespace problem {

branin::branin():base(2,0,1,0,0)
{
        const double lb[] = {-5,0};
        const double ub[] = {10,15};
        set_bounds(lb,ub);
}

base_ptr branin::clone() const
{
        return base_ptr(new branin(*this));
}

void branin::objfun_impl(fitness_vector &fv, const decision_vector &x) const
{
        const double x1 = x[0], x2 = x[1];
        const double a = 1, b = 5.1 / (4 * boost::math::constants::pi<double>() * boost::math::constants::pi<double>()),
                c = 5 / boost::math::constants::pi<double>(), d = 6, e = 10, f = 1 / (8 * boost::math::constants::pi<double>());
        fv[0] = a * (x2 - b * x1 * x1 + c * x1 - d) * (x2 - b * x1 * x1 + c * x1 - d) + e * (1 - f) * std::cos(x1) + e;
}

std::string branin::get_name() const
{
        return "Branin";
}

}}

BOOST_CLASS_EXPORT_IMPLEMENT(pagmo::problem::branin)