reason_discard.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/
 *
 *     Juan Luis Esteban (esteban@cs.upc.edu)
 *         LOGPROG: Logics and Programming Research Group
 *         Office 110, Omega building
 *         Jordi Girona St 1-3, Campus Nord UPC, 08034 Barcelona.   CATALONIA, SPAIN
 *         Webpage: https://www.cs.upc.edu/~esteban/
 *
 *     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 __LAL_DEBUG_DMax_Unc_BnB
#include <string_view>
#endif
#include <cstdint>
 
namespace lal {
namespace detail {
namespace DMax {
namespace unconstrained {
 
enum class reason_discard : int8_t {
    none,
    will_produce_bipartite_arrangement,
 
    /* -- paths -- */
    node_of_antenna_as_thistle,
    thistle_in_bridge_is_not_the_lowest,
    hub_disallows_placement_of_antennas,
 
    /* -- level values -- */
    placement_is_in_conflict_with_level_prediction,
    level_signature_will_not_be_nonincreasing,
    missing_entire_path,
    missing_degree1,
    missing_degree2_lp2,
    missing_degree2_lm2,
    adjacent_vertices_with_equal_level_value,
    node_disallows_placement_of_neighbors,
    placement_fails_level_propagation,
 
    /* -- optimality -- */
    largest_cut_below_minimum,
 
    /* -- symmetry breaking -- */
    nodes_of_equal_level_disobey_lexicographic_order,
    node_leaves_disobey_lexicographic_order,
    roots_of_isomorphic_subtrees_disobey_lexicographic_order,
 
    // Simply to get the amount of items in this enum safely.
    __last_item
};
 
#if defined __LAL_DEBUG_DMax_Unc_BnB
[[nodiscard]] inline constexpr std::string_view reason_discard_to_string
(const reason_discard at) noexcept
{
    switch (at) {
    case reason_discard::none:
        return "Success";
    case reason_discard::will_produce_bipartite_arrangement:
        return "Placing this vertex will produce a bipartite arrangement";
 
    /* -- paths -- */
    case reason_discard::node_of_antenna_as_thistle:
        return "Vertex of antenna as thistle";
    case reason_discard::thistle_in_bridge_is_not_the_lowest:
        return "The vertex is not adequate to be thistle in its bridge";
    case reason_discard::hub_disallows_placement_of_antennas:
        return "The level of the hub of an antenna is not Ok for the placement of the antenna";
    case reason_discard::placement_fails_level_propagation:
        return "Placing this vertex will eventually prevent the placement of some other vertex in the same path";
 
    /* -- level values -- */
    case reason_discard::placement_is_in_conflict_with_level_prediction:
        return "Conflict in the prediction of level value";
    case reason_discard::level_signature_will_not_be_nonincreasing:
        return "The level signature will not be non-increasing";
    case reason_discard::missing_entire_path:
        return "None of the vertices of a path (degree <= 2) has been assigned";
    case reason_discard::missing_degree1:
        return "Some leaf will be misplaced";
    case reason_discard::missing_degree2_lp2:
        return "Some degree-2 vertex of a path (of level +2) will be misplaced";
    case reason_discard::missing_degree2_lm2:
        return "Some degree-2 vertex of a path (of level -2) will be misplaced";
    case reason_discard::adjacent_vertices_with_equal_level_value:
        return "There will be connected vertices (by an edge) with the same level value";
    case reason_discard::node_disallows_placement_of_neighbors:
        return "Placing will eventually lead to breaking two of Nurse's properties";
 
    /* -- optimality -- */
    case reason_discard::largest_cut_below_minimum:
        return "The largest cut is not large enough";
 
    /* -- symmetry breaking -- */
    case reason_discard::nodes_of_equal_level_disobey_lexicographic_order:
        return "Vertices of equal level value are not arranged in lexicographic order";
    case reason_discard::node_leaves_disobey_lexicographic_order:
        return "Leaves attached to the same vertex are not arranged in lexicographic order";
    case reason_discard::roots_of_isomorphic_subtrees_disobey_lexicographic_order:
        return "Roots of isomorphic subtrees are not arranged in lexicographic order";
 
    /* -- */
    case reason_discard::__last_item:
        return "?";
    }
    return "";
}
 
[[nodiscard]] inline inline constexpr std::size_t reason_discard_to_index
(const reason_discard rd) noexcept
{
    return static_cast<std::size_t>(rd);
}
 
[[nodiscard]] static inline constexpr reason_discard index_to_reason_discard
(const std::size_t i) noexcept
{
    return static_cast<reason_discard>(i);
}
#endif
 
} // -- namespace unconstrained
} // -- namespace DMax
} // -- namespace detail
} // -- namespace lal