best_kill_s_policy.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 <algorithm>
#include <vector>

#include "../population.h"
#include "base.h"
#include "base_s_policy.h"
#include "best_kill_s_policy.h"

namespace pagmo { namespace migration {


best_kill_s_policy::best_kill_s_policy(const double &rate, rate_type type):base_s_policy(rate,type) {}

base_s_policy_ptr best_kill_s_policy::clone() const
{
        return base_s_policy_ptr(new best_kill_s_policy(*this));
}

std::vector<population::individual_type> best_kill_s_policy::select(population &pop) const
{
        pagmo_assert(get_n_individuals(pop) <= pop.size());
        // Gets the number of individuals to select
        const population::size_type migration_rate = get_n_individuals(pop);
        // Create a temporary array of individuals.
        std::vector<population::individual_type> result;
        // Gets the indexes of the best individuals
        std::vector<population::size_type> best_idx = pop.get_best_idx(migration_rate);
        // Puts the best individuals in results
        for (population::size_type i =0; i< migration_rate; ++i) {
                result.push_back(pop.get_individual(best_idx[i]));
        }
        // Remove them from the original population 
        // (note: the champion will still carry information on the best guy ...)
        for (population::size_type i=0 ; i<migration_rate; ++i) {
                pop.reinit(best_idx[i]);
        }
        return result;
}

}}

BOOST_CLASS_EXPORT_IMPLEMENT(pagmo::migration::best_kill_s_policy)