rand_lab_free_trees.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
#include <random>
 
// lal includes
#include <lal/basic_types.hpp>
#include <lal/graphs/free_tree.hpp>
#include <lal/generate/tree_generator.hpp>
#include <lal/detail/array.hpp>
 
namespace lal {
namespace generate {
 
class _rand_lab_free_trees {
public:
    /* CONSTRUCTORS */
 
    _rand_lab_free_trees() noexcept { }
 
    _rand_lab_free_trees(const uint64_t n, const uint64_t seed = 0) noexcept {
        init(n, seed);
    }
 
    _rand_lab_free_trees(const _rand_lab_free_trees& Gen) noexcept = default;
 
    _rand_lab_free_trees(_rand_lab_free_trees&& Gen) noexcept = default;
 
    ~_rand_lab_free_trees() = default;
 
    _rand_lab_free_trees& operator= (const _rand_lab_free_trees& g) noexcept = default;
    _rand_lab_free_trees& operator= (_rand_lab_free_trees&& g) noexcept = default;
 
    /* INITIALIZE */
 
    void init(const uint64_t n, const uint64_t seed = 0) noexcept {
        m_n = n;
        m_Prufer_seq.resize(m_n <= 2 ? 2 : m_n - 2);
 
        if (seed == 0) {
            std::random_device rd;
            m_gen = std::mt19937(rd());
        }
        else {
            m_gen = std::mt19937(seed);
        }
        m_unif = std::uniform_int_distribution<uint64_t>(0, m_n - 1);
    }
 
    void clear() noexcept {
        m_Prufer_seq.clear();
    }
 
    /* GETTERS */
 
    [[nodiscard]] graphs::free_tree get_tree() noexcept;
 
protected:
    uint64_t m_n;
 
    std::mt19937 m_gen;
    std::uniform_int_distribution<uint64_t> m_unif;
    detail::array<uint64_t> m_Prufer_seq;
};
 
class rand_lab_free_trees : public _tree_generator<graphs::free_tree> {
public:
    /* CONSTRUCTORS */
 
    rand_lab_free_trees() noexcept : _tree_generator<graphs::free_tree>() { }
 
    rand_lab_free_trees(const uint64_t n, const uint64_t seed = 0) noexcept :
        _tree_generator<graphs::free_tree>(n), m_Gen(n, seed) { }
    rand_lab_free_trees(const rand_lab_free_trees& Gen) = default;
 
    rand_lab_free_trees(rand_lab_free_trees&& Gen) = default;
 
    ~rand_lab_free_trees() = default;
 
    rand_lab_free_trees& operator= (const rand_lab_free_trees& g) noexcept = default;
    rand_lab_free_trees& operator= (rand_lab_free_trees&& g) noexcept = default;
 
    void init(const uint64_t n, const uint64_t seed = 0) noexcept {
        _tree_generator::init(n);
        m_Gen.init(n, seed);
    }
 
    void clear() noexcept {
        _tree_generator::clear();
        m_Gen.clear();
    }
 
    [[nodiscard]] graphs::free_tree yield_tree() noexcept {
        return get_tree();
    }
 
protected:
    [[nodiscard]] graphs::free_tree __get_tree() noexcept
    { return m_Gen.get_tree(); }
 
protected:
    _rand_lab_free_trees m_Gen;
};
 
} // -- namespace generate
} // -- namespace lal