generic.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
 
// lal includes
#include <lal/graphs/rooted_tree.hpp>
#include <lal/linarr/chunking/chunk.hpp>
#include <lal/linarr/chunking/chunk_sequence.hpp>
 
namespace lal {
namespace detail {
 
 
template <class arrangement_t>
class chunks_generic {
public:
    chunks_generic(const graphs::rooted_tree& rt, const arrangement_t& arr)
    noexcept
        : m_rt(rt), m_arr(arr),
          m_n(rt.get_num_nodes())
    {
    }
 
    virtual ~chunks_generic() noexcept { }
 
    const linarr::chunk_sequence& get_chunk_sequence() const noexcept {
        return m_sequence;
    }
    /*
    linarr::chunk_sequence& get_chunk_sequence() noexcept {
        return m_sequence;
    }
    */
    [[nodiscard]] linarr::chunk_sequence&& retrieve_chunk_sequence() noexcept {
        return std::move(m_sequence);
    }
 
protected:
    [[nodiscard]] linarr::chunk& last_chunk() noexcept {
        return m_sequence[m_sequence.size() - 1];
    }
 
    [[nodiscard]] std::size_t node_to_chunk(const node u) const noexcept {
        return m_sequence.get_chunk_index(u);
    }
    void set_chunk_index(const node u, const std::size_t i) noexcept {
        m_sequence.set_chunk_index(u, i);
    }
 
    void set_parent_chunk(linarr::chunk& c) noexcept {
#if defined DEBUG
        bool head_found = false;
#endif
        for (node u : c.get_nodes()) {
 
            // if the parent of 'u' (if it exists) is outside the chunk
            // of 'u', then that parent is the parent of this chunk and 'u'
            // is the root node of the chunk.
            if (m_rt.get_in_degree(u) == 1) {
                const node v = m_rt.get_parent_node(u);
                if (node_to_chunk(v) != node_to_chunk(u)) {
                    c.set_root_node(u);
                    c.set_parent_node(v);
#if defined DEBUG
                    head_found = true;
#endif
                }
            }
            else {
                c.set_root_node(u);
#if defined DEBUG
                head_found = true;
#endif
            }
        }
 
#if defined DEBUG
        assert(head_found);
#endif
    }
 
protected:
    const graphs::rooted_tree& m_rt;
    const arrangement_t m_arr;
    const uint64_t m_n;
 
    linarr::chunk_sequence m_sequence;
};
 
} // -- namespace detail
} // -- namespace lal