levy5.cpp

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

#include "../exceptions.h"
#include "../types.h"
#include "base.h"
#include "levy5.h"

namespace pagmo { namespace problem {


levy5::levy5(int n):base(n)
{
        if (n < 2) {
                pagmo_throw(value_error,"the Levy5 problem's dimension must be at least 2");
        }
        // Set bounds.
        set_lb(-100);
        set_ub(100);
}

base_ptr levy5::clone() const
{
        return base_ptr(new levy5(*this));
}

void levy5::objfun_impl(fitness_vector &f, const decision_vector &x) const
{
        pagmo_assert(f.size() == 1);
        decision_vector::size_type n = x.size();
        double isum = 0.0;
        double jsum = 0.0;
        f[0] = 0;

        for ( decision_vector::size_type j=0; j<n; j+=2 ) {
                for ( int i=1; i<=5; i++ ) {
                        isum += (double)(i) * cos((double)(i-1)*x[j] + (double)(i));
                        jsum += (double)(i) * cos((double)(i+1)*x[j+1] + (double)(i));
                }
        }

        f[0] = isum*jsum;
        for ( decision_vector::size_type j=0; j<n; j+=2 )
                f[0] += pow(x[j] + 1.42513,2) + pow(x[j+1] + 0.80032,2);

}

std::string levy5::get_name() const
{
        return "Levy5";
}

}} //namespaces

BOOST_CLASS_EXPORT_IMPLEMENT(pagmo::problem::levy5)