spot/spot/twaalgos/toparity.hh
Florian Renkin 6dd99e049b to_parity: Rewrite the function and add new transformations
* spot/twaalgos/synthesis.cc: Now needs to call reduce_parity.
* spot/twaalgos/toparity.cc, spot/twaalgos/toparity.hh: here.
* spot/twaalgos/zlktree.hh: make zielonka_node public
* tests/core/ltlsynt.test, tests/python/games.ipynb,
  tests/python/synthesis.ipynb, tests/python/toparity.py:
  update tests
2022-07-07 20:43:21 +02:00

224 lines
10 KiB
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// -*- coding: utf-8 -*-
// Copyright (C) 2018-2020 Laboratoire de Recherche et Développement
// 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 <http://www.gnu.org/licenses/>.
#pragma once
#include <spot/twa/fwd.hh>
#include <spot/misc/common.hh>
#include <vector>
namespace spot
{
/// Structure used by to_parity to store some information about the
/// construction
struct to_parity_data
{
/// Total number of states created
unsigned nb_states_created = 0;
/// Total number of edges created
unsigned nb_edges_created = 0;
/// Name of algorithms used
std::vector<std::string> algorithms_used;
};
/// \ingroup twa_acc_transform
/// \brief Options to control various optimizations of to_parity().
struct to_parity_options
{
/// If \c search_ex is true, whenever CAR or IAR have to move
/// several elements in a record, it tries to find an order such
/// that the new permutation already exists.
bool search_ex = true;
/// If \c use_last is true and \a search_ex are true, we use the
/// most recent state when we find multiple existing state
/// compatible with the current move.
bool use_last = true;
/// If \c use_last_post_process is true, then when LAR ends, it tries to
/// replace the destination of an edge by the newest compatible state.
bool use_last_post_process = false;
/// If \c force_order is true, we force to use an order when CAR or IAR is
/// applied. Given a state s and a set E ({0}, {0 1}, {2} for example) we
/// construct an order on colors. With the given example, we ask to have
/// a permutation that start with [0 …], [0 1 …] or [2 …] in
/// that order of preference.
bool force_order = true;
/// If \c partial_degen is true, apply a partial
/// degeneralization to remove occurrences of acceptance
/// subformulas such as `Fin(x) | Fin(y)` or `Inf(x) & Inf(y)`.
bool partial_degen = true;
/// If \c scc_acc_clean is true, to_parity() will ignore colors
/// not occurring in an SCC while processing this SCC.
bool acc_clean = true;
/// If \c parity_equiv is true, to_parity() will check if there
/// exists a way to see the acceptance condition as a parity max one.
bool parity_equiv = true;
/// If \c Car is true, to_parity will try to apply CAR. It is a version of
/// LAR that tracks colors.
bool car = true;
/// If \c tar is true, to_parity will try to apply TAR. It is a version of
/// LAR that tracks transitions instead of colors.
bool tar = false;
/// If \c iar is true, to_parity will try to apply IAR.
bool iar = true;
/// if \c lar_dfs is true, then when LAR is used the next state of the
/// result that will be processed is the last created state.
bool lar_dfs = true;
/// If \c bscc is true, to_parity() will only keep the bottommost automaton
/// when it applies LAR.
bool bscc = true;
/// If \c parity_prefix is true, to_parity() will use a special
/// handling for acceptance conditions of the form `Inf(m0) |
/// (Fin(m1) & (Inf(m2) | (… β)))` that start as a parity
/// condition (modulo a renumbering of `m0`, `m1`, `m2`, ...) but where
/// `β` can be an arbitrary formula. In this case, the paritization
/// algorithm is really applied only to `β`, and the marks of the
/// prefix are appended after a suitable renumbering.
bool parity_prefix = true;
/// If \c parity_prefix_general is true, to_parity() will rewrite the
/// acceptance condition as `Inf(m0) | (Fin(m1) & (Inf(m2) | (… β)))` before
/// applying the same construction as with the option \c parity_prefix.
bool parity_prefix_general = false;
/// If \c generic_emptiness is true, to_parity() will check if the automaton
/// does not accept any word with an emptiness check algorithm.
bool generic_emptiness = false;
/// If \c rabin_to_buchi is true, to_parity() tries to convert a Rabin or
/// Streett condition to Büchi or co-Büchi with
/// rabin_to_buchi_if_realizable().
bool rabin_to_buchi = true;
/// If \c buchi_type_to_buchi is true, to_parity converts a
/// (co-)Büchi type automaton to a (co-)Büchi automaton.
bool buchi_type_to_buchi = false;
/// If \c parity_type_to_parity is true, to_parity converts a
/// parity type automaton to a parity automaton.
bool parity_type_to_parity = false;
/// Only allow partial degeneralization if it reduces the number of colors
/// in the acceptance condition or if it implies to apply IAR instead of
/// CAR.
bool reduce_col_deg = false;
/// Use propagate_marks_here to increase the number of marks on transition
/// in order to move more colors (and increase the number of
/// compatible states) when we apply LAR.
bool propagate_col = true;
/// If \c use_generalized_buchi is true, each SCC will use a generalized
/// Rabin acceptance in order to avoid CAR.
bool use_generalized_rabin = false;
/// If \c pretty_print is true, states of the output automaton are
/// named to help debugging.
bool pretty_print = false;
/// Structure used to store some information about the construction.
to_parity_data* datas = nullptr;
};
/// \ingroup twa_acc_transform
/// \brief Take an automaton with any acceptance condition and return an
/// equivalent parity automaton.
///
/// If the input is already a parity automaton of any kind, it is
/// returned unchanged. Otherwise a new parity automaton with max
/// odd or max even condition is created.
///
/// This procedure combines many strategies in an attempt to produce
/// the smallest possible parity automaton. Some of the strategies
/// include CAR (color acceptance record), IAR (index appearance
/// record), partial degenerazation, conversion from Rabin to Büchi
/// when possible, etc.
///
/// The \a options argument can be used to selectively disable some of the
/// optimizations.
SPOT_API twa_graph_ptr
to_parity(const const_twa_graph_ptr &aut,
const to_parity_options options = to_parity_options());
/// \ingroup twa_acc_transform
/// \brief Take an automaton with any acceptance condition and return an
/// equivalent parity automaton.
///
/// The parity condition of the returned automaton is max even.
///
/// This implements a straightforward adaptation of the LAR (latest
/// appearance record) to automata with transition-based marks. We
/// call this adaptation the CAR (color apperance record), as it
/// tracks colors (i.e., acceptance sets) instead of states.
///
/// It is better to use to_parity() instead, as it will use better
/// strategies when possible, and has additional optimizations.
SPOT_API twa_graph_ptr
to_parity_old(const const_twa_graph_ptr& aut, bool pretty_print = false);
/// \ingroup twa_acc_transform
/// \brief Turn a Rabin-like or Streett-like automaton into a parity automaton
/// based on the index appearence record (IAR)
///
/// This is an implementation of \cite kretinsky.17.tacas .
/// If the input automaton has n states and k pairs, the output automaton has
/// at most k!*n states and 2k+1 colors. If the input automaton is
/// deterministic, the output automaton is deterministic as well, which is the
/// intended use case for this function. If the input automaton is
/// non-deterministic, the result is still correct, but way larger than an
/// equivalent Büchi automaton.
///
/// If the input automaton is Rabin-like (resp. Streett-like), the output
/// automaton has max odd (resp. min even) acceptance condition.
///
/// Throws an std::runtime_error if the input is neither Rabin-like nor
/// Street-like.
///
/// It is better to use to_parity() instead, as it will use better
/// strategies when possible, and has additional optimizations.
SPOT_DEPRECATED("use to_parity() instead") // deprecated since Spot 2.9
SPOT_API twa_graph_ptr
iar(const const_twa_graph_ptr& aut, bool pretty_print = false);
/// \ingroup twa_acc_transform
/// \brief Turn a Rabin-like or Streett-like automaton into a parity automaton
/// based on the index appearence record (IAR)
///
/// Returns nullptr if the input automaton is neither Rabin-like nor
/// Streett-like, and calls spot::iar() otherwise.
SPOT_DEPRECATED("use to_parity() and spot::acc_cond::is_rabin_like() instead")
SPOT_API twa_graph_ptr // deprecated since Spot 2.9
iar_maybe(const const_twa_graph_ptr& aut, bool pretty_print = false);
/// \ingroup twa_acc_transform
/// \brief Convert an automaton into a parity max automaton preserving
/// structure when possible.
///
/// Return nullptr if no such automaton is found.
/// \param aut Automaton that we want to convert
SPOT_API twa_graph_ptr
parity_type_to_parity(const twa_graph_ptr &aut);
/// \ingroup twa_acc_transform
/// \brief Convert an automaton into a Büchi automaton preserving structure
/// when possible.
///
/// Return nullptr if no such automaton is found.
/// \param aut Automaton that we want to convert
SPOT_API twa_graph_ptr
buchi_type_to_buchi(const twa_graph_ptr &aut);
/// \ingroup twa_acc_transform
/// \brief Convert an automaton into a co-Büchi automaton preserving structure
/// when possible.
///
/// Return nullptr if no such automaton is found.
/// \param aut Automaton that we want to convert
SPOT_API twa_graph_ptr
co_buchi_type_to_co_buchi(const twa_graph_ptr &aut);
}