C_rla.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
 
// lal includes
#include <lal/numeric/rational.hpp>
#include <lal/graphs/undirected_graph.hpp>
#include <lal/graphs/free_tree.hpp>
#include <lal/graphs/rooted_tree.hpp>
 
namespace lal {
namespace properties {
 
// C: the number of crossings
 
/* -------------------------- */
/* EXPECTATION OF C: E_rla[C] */
 
numeric::rational exp_num_crossings_rational(const graphs::undirected_graph& g)
noexcept;
inline
double exp_num_crossings(const graphs::undirected_graph& g) noexcept
{ return exp_num_crossings_rational(g).to_double(); }
 
/* ----------------------- */
/* VARIANCE OF C: V_rla[C] */
 
// ---------------------------
// VARIANCE FOR GENERAL GRAPHS
 
numeric::rational var_num_crossings_rational
(const graphs::undirected_graph& g, bool reuse = true) noexcept;
inline
double var_num_crossings(const graphs::undirected_graph& g, bool reuse = true)
noexcept
{ return var_num_crossings_rational(g, reuse).to_double(); }
 
// --------------------
// VARIANCE FOR FORESTS
 
numeric::rational var_num_crossings_forest_rational(const graphs::undirected_graph& g)
noexcept;
inline
double var_num_crossings_forest(const graphs::undirected_graph& g) noexcept
{ return var_num_crossings_forest_rational(g).to_double(); }
 
// ------------------
// VARIANCE FOR TREES
 
inline
numeric::rational var_num_crossings_tree_rational(const graphs::free_tree& t)
noexcept {
#if defined DEBUG
    assert(t.is_tree());
#endif
    return var_num_crossings_forest_rational(t);
}
inline
double var_num_crossings_tree(const graphs::free_tree& t) noexcept {
#if defined DEBUG
    assert(t.is_tree());
#endif
    return var_num_crossings_forest_rational(t).to_double();
}
 
inline
numeric::rational var_num_crossings_tree_rational(const graphs::rooted_tree& t)
noexcept {
#if defined DEBUG
    assert(t.is_tree());
#endif
    return var_num_crossings_forest_rational(t.to_free_tree());
}
inline
double var_num_crossings_tree(const graphs::rooted_tree& t) noexcept {
#if defined DEBUG
    assert(t.is_tree());
#endif
    return var_num_crossings_forest_rational(t.to_free_tree()).to_double();
}
 
} // -- namespace properties
} // -- namespace lal