aggregations.hpp

/*********************************************************************
 *
 * Linear Arrangement Library - A library that implements a collection
 * algorithms for linear arrangments of graphs.
 *
 * Copyright (C) 2019 - 2024
 *
 * This file is part of Linear Arrangement Library. The full code is available
 * at:
 *      https://github.com/LAL-project/linear-arrangement-library.git
 *
 * Linear Arrangement Library is free software: you can redistribute it
 * and/or modify it under the terms of the GNU Affero General Public License
 * as published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * Linear Arrangement Library is distributed in the hope that it will be
 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with Linear Arrangement Library.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Contact:
 *
 *     Lluís Alemany Puig (lluis.alemany.puig@upc.edu)
 *         LQMC (Quantitative, Mathematical, and Computational Linguisitcs)
 *         CQL (Complexity and Quantitative Linguistics Lab)
 *         Jordi Girona St 1-3, Campus Nord UPC, 08034 Barcelona.   CATALONIA, SPAIN
 *         Webpage: https://cqllab.upc.edu/people/lalemany/
 *
 *     Ramon Ferrer i Cancho (rferrericancho@cs.upc.edu)
 *         LQMC (Quantitative, Mathematical, and Computational Linguisitcs)
 *         CQL (Complexity and Quantitative Linguistics Lab)
 *         Office 220, Omega building
 *         Jordi Girona St 1-3, Campus Nord UPC, 08034 Barcelona.   CATALONIA, SPAIN
 *         Webpage: https://cqllab.upc.edu/people/rferrericancho/
 *
 ********************************************************************/
 
#pragma once
 
// C++ includes
#if defined DEBUG
#include <iterator>
#include <cassert>
#endif
#include <cstddef>
 
namespace lal {
namespace utilities {
 
template <
    typename result_t, bool second_set_empty,
    typename iterator_first_t, typename iterator_second_t,
    class metric,
    class accumulate_Q, class accumulate_R,
    class make_average_Q, class make_average_R,
    class make_average
>
[[nodiscard]] result_t one_level_aggregation
(
    iterator_first_t bfirst,
    const iterator_first_t efirst,
    iterator_second_t bsecond,
    [[maybe_unused]] const iterator_second_t esecond,
    metric values,
    accumulate_Q accQ,
    accumulate_R accR,
    make_average_Q avgQ,
    make_average_R avgR,
    make_average avg
)
noexcept
{
    if constexpr (second_set_empty) {
        // no elements from the second set
        auto [total_Q, total_R] = values(*bfirst);
        std::size_t amount = 1;
 
        ++bfirst;
        for (; bfirst != efirst; ++bfirst, ++amount) {
            const auto [Qi, Ri] = values(*bfirst);
            accQ(total_Q, Qi);
            accR(total_R, Ri);
        }
 
        return avg(avgQ(total_Q, amount), avgR(total_R, amount));
    }
    else {
#if defined DEBUG
        // ensure same number of elements in both sets
        assert(std::distance(bfirst, efirst) == std::distance(bsecond, esecond));
#endif
 
        auto [total_Q, total_R] = values(*bfirst, *bsecond);
        std::size_t amount = 1;
 
        ++bfirst; ++bsecond;
        for (; bfirst != efirst; ++bfirst, ++bsecond, ++amount) {
            const auto [Qi, Ri] = values(*bfirst, *bsecond);
            accQ(total_Q, Qi);
            accR(total_R, Ri);
        }
 
        return avg(avgQ(total_Q, amount), avgR(total_R, amount));
    }
}
 
template <
    typename result_t, bool second_set_empty,
    typename iterator_first_t,
    typename iterator_second_t,
    class metric, class combine, class accumulate, class make_average
>
[[nodiscard]] result_t two_level_aggregation
(
    iterator_first_t bfirst,
    const iterator_first_t efirst,
    iterator_second_t bsecond,
    [[maybe_unused]] const iterator_second_t esecond,
    metric values,
    combine comb_values,
    accumulate acc_values,
    make_average avg
)
noexcept
{
    if constexpr (second_set_empty) {
        // no elements from the second set
        auto total = comb_values(values(*bfirst));
        std::size_t amount = 1;
 
        ++bfirst;
        for (; bfirst != efirst; ++bfirst, ++amount) {
            acc_values(total, comb_values(values(*bfirst)));
        }
        return avg(total, amount);
    }
    else {
#if defined DEBUG
        // ensure same of elements in both sets
        assert(std::distance(bfirst, efirst) == std::distance(bsecond, esecond));
#endif
        auto total = comb_values(values(*bfirst, *bsecond));
        std::size_t amount = 1;
 
        ++bfirst; ++bsecond;
        for (; bfirst != efirst; ++bfirst, ++bsecond, ++amount) {
            acc_values(total, comb_values(values(*bfirst, *bsecond)));
        }
        return avg(total, amount);
    }
}
 
} // -- namespace utilities
} // -- namespace lal