facility_location_swap.hpp

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//=======================================================================
// Copyright (c) 2013 Piotr Wygocki
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//=======================================================================
#ifndef PAAL_FACILITY_LOCATION_SWAP_HPP
#define PAAL_FACILITY_LOCATION_SWAP_HPP

#include "paal/data_structures/facility_location/facility_location_solution_traits.hpp"
#include "paal/utils/type_functions.hpp"
#include "paal/data_structures/combine_iterator.hpp"

#include <boost/iterator/iterator_adaptor.hpp>
#include <boost/iterator/transform_iterator.hpp>

#include <cassert>
#include <vector>
#include <numeric>
#include <cstdlib>

namespace paal {
namespace local_search {

template <typename T> class Swap {
  public:
    Swap(T from, T to) : m_from(from), m_to(to) {}

    Swap() = default;

    T get_from() const { return m_from; }

    T get_to() const { return m_to; }

    void set_from(T from) { m_from = from; }

    void set_to(T to) { m_to = to; }

  private:
    T m_from;
    T m_to;
};

struct make_swap {
    template <typename T> Swap<T> operator()(T from, T to) const {
        return Swap<T>(from, to);
    }
};

struct facility_location_gain_swap {
    template <class Solution, class VertexType>
    auto operator()(Solution &sol, const Swap<VertexType> &s) const {

        auto ret = sol.add_facility_tentative(s.get_to());
        ret += sol.remove_facility_tentative(s.get_from());
        auto back = sol.add_facility_tentative(s.get_from());
        back += sol.remove_facility_tentative(s.get_to());
        assert(ret == -back);
        return -ret;
    }
};

struct facility_location_commit_swap {
    template <typename Solution, typename VertexType>
    bool operator()(Solution &sol, const Swap<VertexType> &s) const {
        sol.add_facility(s.get_to());
        sol.remove_facility(s.get_from());
        return true;
    }
};

struct facility_locationget_moves_swap {

    template <typename Solution>
    auto operator()(const Solution &s) const  {
        auto begin = data_structures::make_combine_iterator(
            make_swap{}, s.getChosenCopy(), s.getUnchosenCopy());
        decltype(begin) end;
        return boost::make_iterator_range(begin, end);
    }
};

} // local_search
} // paal

#endif // PAAL_FACILITY_LOCATION_SWAP_HPP