directed_graph.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 <cassert>
#endif
#include <vector>
 
// lal includes
#include <lal/basic_types.hpp>
#include <lal/graphs/graph.hpp>
#include <lal/graphs/undirected_graph.hpp>
 
namespace lal {
namespace graphs {
 
class directed_graph : virtual public graph {
public:
    /* CONSTRUCTORS */
 
    directed_graph() noexcept : graph() { }
    directed_graph(const uint64_t n) noexcept {
        init(n);
    }
    directed_graph(const directed_graph& g) noexcept : graph() {
        copy_full_directed_graph(g);
    }
 
    directed_graph(directed_graph&& g) noexcept {
        move_full_directed_graph(std::forward<directed_graph>(g));
    }
 
    virtual ~directed_graph() noexcept { }
 
    /* OPERATORS */
 
    directed_graph& operator= (const directed_graph& g) noexcept {
        copy_full_directed_graph(g);
        return *this;
    }
    directed_graph& operator= (directed_graph&& g) noexcept {
        move_full_directed_graph(std::forward<directed_graph>(g));
        return *this;
    }
 
    /* MODIFIERS */
 
    void reserve_in_degree(const node u, const uint64_t d) noexcept {
#if defined DEBUG
        assert(u < get_num_nodes());
#endif
        m_in_adjacency_list[u].reserve(d);
    }
    void reserve_out_degree(const node u, const uint64_t d) noexcept {
#if defined DEBUG
        assert(u < get_num_nodes());
#endif
        m_adjacency_list[u].reserve(d);
    }
 
    void normalize() noexcept;
 
    [[nodiscard]] bool check_normalized() noexcept;
 
    virtual directed_graph& add_node() noexcept {
        graph::__add_node();
        m_in_adjacency_list.emplace_back();
        return *this;
    }
 
    virtual directed_graph& remove_node
    (
        const node u,
        const bool norm = true,
        const bool check_norm = true
    )
    noexcept;
 
    virtual directed_graph& add_edge
    (
        const node s,
        const node t,
        const bool norm = true,
        const bool check_norm = true
    )
    noexcept;
 
    directed_graph& add_edge_bulk(const node s, const node t) noexcept;
    
    void finish_bulk_add(const bool norm = true, const bool check = true) noexcept;
 
    virtual directed_graph& add_edges
    (
        const std::vector<edge>& edges,
        const bool norm = true,
        const bool check_norm = true
    )
    noexcept;
 
    virtual directed_graph& set_edges
    (
        const std::vector<edge>& edges,
        const bool norm = true,
        const bool check_norm = true
    )
    noexcept;
 
    virtual directed_graph& remove_edge_bulk(const node s, const node t) noexcept;
 
    void finish_bulk_remove(const bool norm = true, const bool check = true) noexcept;
 
    virtual directed_graph& remove_edge
    (
        const node s,
        const node t,
        const bool norm = true,
        const bool check_norm = true
    )
    noexcept;
 
    virtual directed_graph& remove_edges
    (const std::vector<edge>& edges, const bool norm = true, const bool check_norm = true)
    noexcept;
 
    virtual directed_graph& remove_edges_incident_to
    (const node u, const bool norm = true, const bool check_norm = true)
    noexcept;
 
    directed_graph& disjoint_union(const directed_graph& g) noexcept;
 
    /* SETTERS */
 
    /* GETTERS */
 
    [[nodiscard]] std::vector<edge_pair> get_Q() const noexcept;
 
    [[nodiscard]] std::vector<edge> get_edges() const noexcept;
 
    [[nodiscard]] bool has_edge(const node u, const node v) const noexcept;
 
    [[nodiscard]] const neighbourhood& get_out_neighbors(const node u) const noexcept {
#if defined DEBUG
        assert(has_node(u));
#endif
        return m_adjacency_list[u];
    }
    [[nodiscard]] const neighbourhood& get_in_neighbors(const node u) const noexcept {
#if defined DEBUG
        assert(has_node(u));
#endif
        return m_in_adjacency_list[u];
    }
 
    [[nodiscard]] uint64_t get_degree(const node u) const noexcept
    { return get_out_degree(u) + get_in_degree(u); }
 
    [[nodiscard]] uint64_t get_out_degree(const node u) const noexcept {
#if defined DEBUG
        assert(has_node(u));
#endif
        return m_adjacency_list[u].size();
    }
    [[nodiscard]] uint64_t get_in_degree(const node u) const noexcept {
#if defined DEBUG
        assert(has_node(u));
#endif
        return m_in_adjacency_list[u].size();
    }
 
    [[nodiscard]] bool is_directed() const noexcept { return true; }
    [[nodiscard]] bool is_undirected() const noexcept { return false; }
 
    [[nodiscard]] undirected_graph to_undirected
    (const bool norm = true, const bool check = true)
    const noexcept;
 
    [[nodiscard]] std::vector<directed_graph> get_connected_components() const noexcept;
 
protected:
    std::vector<neighbourhood> m_in_adjacency_list;
 
protected:
    virtual void _init(const uint64_t n) noexcept {
        graph::_init(n);
        m_in_adjacency_list.resize(n);
    }
    virtual void _clear() noexcept {
        graph::_clear();
        m_in_adjacency_list.clear();
    }
 
    virtual void actions_after_add_edge(const node u, const node v) noexcept;
 
    virtual void actions_after_add_edges(const edge_list& e) noexcept;
 
    virtual void actions_after_add_edges_bulk() noexcept;
 
    virtual void actions_after_remove_edge(const node u, const node v) noexcept;
 
    virtual void actions_after_remove_edges(const edge_list& e) noexcept;
 
    virtual void actions_after_remove_edges_bulk() noexcept;
 
    virtual void actions_before_remove_edges_incident_to(const node u) noexcept;
 
    virtual void actions_after_remove_node(const node u) noexcept;
 
    void copy_full_directed_graph(const directed_graph& d) noexcept {
        // copy parent class
        copy_full_graph(d);
 
        // copy this class' members
        m_in_adjacency_list = d.m_in_adjacency_list;
    }
    void move_full_directed_graph(directed_graph&& d) noexcept {
        // move-assign parent class
        move_full_graph(std::forward<directed_graph>(d));
 
        // move-assign this class' members
        m_in_adjacency_list = std::move(d.m_in_adjacency_list);
    }
 
private:
    void remove_single_edge
    (
        const node u,
        const node v,
        neighbourhood& out_u,
        neighbourhood& in_v
    )
    noexcept;
};
 
} // -- namespace graphs
} // -- namespace lal