utils.hpp

/*********************************************************************
 *
 * Linear Arrangement Library - A library that implements a collection
 * algorithms for linear arrangments of graphs.
 *
 * Copyright (C) 2019 - 2023
 *
 * 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 (lalemany@cs.upc.edu)
 *         LARCA (Laboratory for Relational Algorithmics, Complexity and Learning)
 *         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)
 *         LARCA (Laboratory for Relational Algorithmics, Complexity and Learning)
 *         CQL (Complexity and Quantitative Linguistics Lab)
 *         Office S124, 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
#include <algorithm>
 
// lal includes
#include <lal/graphs/directed_graph.hpp>
#include <lal/graphs/undirected_graph.hpp>
 
namespace lal {
namespace detail {
 
template <
    class graph_t,
    typename char_type,
    std::enable_if_t<
        std::is_base_of_v<graphs::graph, graph_t>
        && std::is_integral_v<char_type>,
    bool> = true
>
void get_bool_neighbours(const graph_t& g, node u, char_type * const neighs)
noexcept
{
    if constexpr (std::is_base_of_v<graphs::directed_graph, graph_t>) {
        const auto& in_u = g.get_in_neighbours(u);
        std::for_each(in_u.begin(), in_u.end(), [&](node v) { neighs[v] = 1; });
        const auto& out_u = g.get_out_neighbours(u);
        std::for_each(out_u.begin(), out_u.end(), [&](node v) { neighs[v] = 1; });
    }
    else {
        const auto& neighs_u = g.get_neighbours(u);
        std::for_each(neighs_u.begin(), neighs_u.end(), [&](node v) { neighs[v] = 1; });
    }
}
 
inline
void append_adjacency_lists
(std::vector<neighbourhood>& target, const std::vector<neighbourhood>& source)
noexcept
{
    const uint64_t n_target = target.size();
    for (std::size_t u = 0; u < source.size(); ++u) {
        // add new edges by appending all the neighbours of 'u' in 'g'
        target.push_back( source[u] );
        // relabel the nodes
        for (node& v : target.back()) {
            v += n_target;
        }
    }
}
 
} // -- namespace detail
} // -- namespace lal