tens_comp_string.cpp

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

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

static const std::vector<double> __constraint_tolerances__(int c_dimension, int ic_dimension)
{
        std::vector<double> constraint_tolerances(c_dimension);
        // equality constraints
        for(int i=0; i<c_dimension-ic_dimension; i++) {
                constraint_tolerances[i] = 0.0001;
        }
        // inequality constraints
        for(int i=c_dimension-ic_dimension; i<c_dimension; i++) {
                constraint_tolerances[i] = 0.;
        }
        return constraint_tolerances;
}

namespace pagmo { namespace problem {


tens_comp_string::tens_comp_string():base(3,0,1,4,4,__constraint_tolerances__(4,4))
{
        // initialize best solution
        initialize_best();

        // set the bounds for the current problem
        const double lb[] = {0.05,0.25,2.};
        const double ub[] = {2.,1.3,15.};
        set_bounds(lb,ub);
}

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

void tens_comp_string::objfun_impl(fitness_vector &f, const decision_vector &x) const
{
        /* objective function */
        f[0] = x[0]*x[0] * x[1] * (x[2] + 2.);
}

void tens_comp_string::compute_constraints_impl(constraint_vector &c, const decision_vector &x) const
{
        c[0] = 1. - (x[1]*x[1]*x[1] * x[2]) / (71785. * x[0]*x[0]*x[0]*x[0]);
        c[1] = (4. * x[1]*x[1] - x[0] * x[1]) /
                        ( 12566. * x[0]*x[0]*x[0] * (x[1] - x[0]) ) +
                        1./(5108. * x[0]*x[0]) - 1.;
        c[2] = 1. - 140.45 * x[0] / (x[2] * x[1]*x[1]);
        c[3] = (x[0] + x[1]) / 1.5 - 1.;
}

std::string tens_comp_string::get_name() const
{
        std::string retval("Tension compression string");
        return retval;
}

void tens_comp_string::initialize_best(void)
{
        std::vector<decision_vector> best_x;

        int x_dimension = 3;
        // He and Wang
        const double x_vector[] = {0.051728, 0.357644, 11.244543};

        decision_vector x(x_dimension);
        std::copy(x_vector,x_vector + x_dimension,x.begin());
        best_x.push_back(x);

        set_best_x(best_x);
}

}} //namespaces

BOOST_CLASS_EXPORT_IMPLEMENT(pagmo::problem::tens_comp_string)