// -*- coding: utf-8 -*-
// Copyright (C) 2012, 2013 Laboratoire de Recherche et DÃ©veloppement
// de l'Epita (LRDE).
//
// This file is part of Spot, a model checking library.
//
// Spot is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 3 of the License, or
// (at your option) any later version.
//
// Spot 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 General Public
// License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see .
#ifndef SPOT_TGBAALGOS_SIMULATION_HH
# define SPOT_TGBAALGOS_SIMULATION_HH
namespace spot
{
class tgba;
/// \addtogroup tgba_reduction
/// @{
/// @{
/// \brief Attempt to reduce the automaton by direct simulation.
///
/// When the suffixes (letter and acceptance conditions) reachable
/// from one state are included in the suffixes seen by another one,
/// the former state can be merged into the latter. The algorithm is
/// based on the following paper, but generalized to handle TGBA
/// directly.
///
/// \verbatim
/// @InProceedings{ etessami.00.concur,
/// author = {Kousha Etessami and Gerard J. Holzmann},
/// title = {Optimizing {B\"u}chi Automata},
/// booktitle = {Proceedings of the 11th International Conference on
/// Concurrency Theory (Concur'00)},
/// pages = {153--167},
/// year = {2000},
/// editor = {C. Palamidessi},
/// volume = {1877},
/// series = {Lecture Notes in Computer Science},
/// address = {Pennsylvania, USA},
/// publisher = {Springer-Verlag}
/// }
/// \endverbatim
///
/// Our reconstruction of the quotient automaton based on this
/// suffix-inclusion relation will also improve determinism.
///
/// We recommend to call scc_filter() to first simplify the
/// automaton that should be reduced by simulation.
///
/// Reducing an automaton by simulation does not change the number
/// of acceptance conditions. In some rare cases (1 out of more
/// than 500 in our benchmark), the reduced automaton will use more
/// acceptance conditions than necessary, and running scc_filter()
/// again afterwards will remove these superfluous conditions.
///
/// \param automaton the automaton to simulate.
/// \return a new automaton which is at worst a copy of the received
/// one
tgba* simulation(const tgba* automaton);
tgba* simulation_sba(const tgba* automaton);
/// @}
/// @{
/// \brief Attempt to reduce the automaton by reverse simulation.
///
/// When the prefixes (letter and acceptance conditions) leading to
/// one state are included in the prefixes leading to one, the former
/// state can be merged into the latter.
///
/// Reverse simulation is discussed in the following paper, bu
/// following paper, but generalized to handle TGBA directly.
/// \verbatim
/// @InProceedings{ somenzi.00.cav,
/// author = {Fabio Somenzi and Roderick Bloem},
/// title = {Efficient {B\"u}chi Automata for {LTL} Formul{\ae}},
/// booktitle = {Proceedings of the 12th International Conference on
/// Computer Aided Verification (CAV'00)},
/// pages = {247--263},
/// year = {2000},
/// volume = {1855},
/// series = {Lecture Notes in Computer Science},
/// address = {Chicago, Illinois, USA},
/// publisher = {Springer-Verlag}
/// }
/// \endverbatim
///
/// Our reconstruction of the quotient automaton based on this
/// prefix-inclusion relation will also improve codeterminism.
///
/// We recommend to call scc_filter() to first simplify the
/// automaton that should be reduced by cosimulation.
///
/// Reducing an automaton by reverse simulation (1) does not change
/// the number of acceptance conditions so the resulting automaton
/// may have superfluous acceptance conditions, and (2) can create
/// SCCs that are terminal and non-accepting. For these reasons,
/// you should call scc_filer() to prune useless SCCs and acceptance
/// conditions afterwards.
///
/// If you plan to run both simulation() and cosimulation() on the
/// same automaton, you should start with simulation() so that the
/// codeterminism improvements achieved by cosimulation() does not
/// hinder the determinism improvements attempted by simulation().
/// (This of course assumes that you prefer determinism over
/// codeterminism.)
///
/// \param automaton the automaton to simulate.
/// \return a new automaton which is at worst a copy of the received
/// one
tgba* cosimulation(const tgba* automaton);
tgba* cosimulation_sba(const tgba* automaton);
/// @}
/// @{
/// \brief Iterate simulation() and cosimulation().
///
/// Runs simulation(), cosimulation(), and scc_filter() in a loop,
/// until the automaton does not change size (states and
/// transitions).
///
/// We recommend to call scc_filter() to first simplify the
/// automaton that should be reduced by iterated simulations, since
/// this algorithm will only call scc_filter() at the end of the
/// loop.
///
/// \param automaton the automaton to simulate.
/// \return a new automaton which is at worst a copy of the received
/// one
tgba* iterated_simulations(const tgba* automaton);
tgba* iterated_simulations_sba(const tgba* automaton);
/// @}
tgba* dont_care_simulation(const tgba* t, int limit = -1);
tgba*
dont_care_iterated_simulations(const tgba* t, int limit = -1);
/// @}
} // End namespace spot.
#endif // !SPOT_TGBAALGOS_SIMULATION_HH