shifted.cpp

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 *   Copyright (C) 2004-2015 The PaGMO development team,                     *
 *   Advanced Concepts Team (ACT), European Space Agency (ESA)               *
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#include <cmath>

#include "../exceptions.h"
#include "../types.h"
#include "../population.h"
#include "base.h"
#include "shifted.h"

namespace pagmo { namespace problem {

shifted::shifted(const base & p,
                                 const decision_vector & translation):
                base_meta(
                 p,
                 p.get_dimension(),
                 p.get_i_dimension(),
                 p.get_f_dimension(),
                 p.get_c_dimension(),
                 p.get_ic_dimension(),
                 p.get_c_tol()),
                m_translation(translation)
{
        if (translation.size() != p.get_dimension()) {
                pagmo_throw(value_error,"The size of the shifting vector must be equal to the problem dimension");
        }
        configure_shifted_bounds(m_translation);
}


shifted::shifted(const base & p,
                                 const double t):
                base_meta(
                 p,
                 p.get_dimension(),
                 p.get_i_dimension(),
                 p.get_f_dimension(),
                 p.get_c_dimension(),
                 p.get_ic_dimension(),
                 p.get_c_tol()),
                m_translation(decision_vector(p.get_dimension(), t))
{
        configure_shifted_bounds(m_translation);
}

shifted::shifted(const base & p):
        base_meta(
                 p,
                 p.get_dimension(),
                 p.get_i_dimension(),
                 p.get_f_dimension(),
                 p.get_c_dimension(),
                 p.get_ic_dimension(),
                 p.get_c_tol()),
                m_translation(decision_vector(p.get_dimension(),0))
{
        for (size_t i=0; i< m_translation.size();++i) {
                m_translation[i] = (2*((double) rand() / (RAND_MAX))-1) * (p.get_ub()[i]-p.get_lb()[i]);
        }
        configure_shifted_bounds(m_translation);
}

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

void shifted::configure_shifted_bounds(const decision_vector & translation)
{
        decision_vector shifted_lb = m_original_problem->get_lb();
        decision_vector shifted_ub = m_original_problem->get_ub();

        for(problem::base::size_type i = 0; i < shifted_lb.size(); ++i) {
                shifted_lb[i] += translation[i];
                shifted_ub[i] += translation[i];
        }
        set_bounds(shifted_lb, shifted_ub);
}

decision_vector shifted::deshift(const decision_vector& x) const
{
        //TODO Need some assertion here?
        decision_vector x_translated(x.size(), 0);
        for(problem::base::size_type i = 0; i < x.size(); ++i) {
                x_translated[i] = x[i] - m_translation[i];
        }
        return x_translated;
}

void shifted::objfun_impl(fitness_vector &f, const decision_vector &x) const
{
        decision_vector x_translated = deshift(x);
        m_original_problem->objfun(f, x_translated);
}

void shifted::compute_constraints_impl(constraint_vector &c, const decision_vector &x) const
{
        decision_vector x_translated = deshift(x);
        m_original_problem->compute_constraints(c, x_translated);
}

const decision_vector& shifted::get_shift_vector() const {
        return m_translation;
}

std::string shifted::get_name() const
{
        return m_original_problem->get_name() + " [Shifted]"; 
}


std::string shifted::human_readable_extra() const
{
        std::ostringstream oss;
        oss << m_original_problem->human_readable_extra() << std::endl;
        oss << "\n\tShift vector: " << m_translation << std::endl;
        return oss.str();
}
}}

BOOST_CLASS_EXPORT_IMPLEMENT(pagmo::problem::shifted)