C_rla.hpp

/*********************************************************************
 *
 *  Linear Arrangement Library - A library that implements a collection
 *  algorithms for linear arrangments of graphs.
 *
 *  Copyright (C) 2019 - 2021
 *
 *  This file is part of Linear Arrangement Library. To see the full code
 *  visit the webpage:
 *      https://github.com/lluisalemanypuig/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