introduce delay_branching_here
This is motivated by an example sent by Edmond Irani Liu, that will be tested in next patch. * spot/twaalgos/dbranch.cc, spot/twaalgos/dbranch.hh: New files. * python/spot/impl.i, spot/twaalgos/Makefile.am: Add them. * spot/twaalgos/translate.cc: Call delay_branching_here unconditionally. * spot/twa/twagraph.cc (defrag_states): Do not assume that games are alternating. * tests/core/genltl.test: Adjust expected numbers. * tests/python/dbranch.py: New file. * tests/Makefile.am: Add it.
This commit is contained in:
Alexandre Duret-Lutz
parent
aa7992c65f
commit
3efab05cf2
10 changed files with 378 additions and 24 deletions
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@ -1,5 +1,5 @@
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## -*- coding: utf-8 -*-
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## Copyright (C) 2008-2018, 2020-2021 Laboratoire de Recherche et
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## Copyright (C) 2008-2018, 2020-2022 Laboratoire de Recherche et
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## Développement de l'Epita (LRDE).
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## Copyright (C) 2003-2005 Laboratoire d'Informatique de Paris 6
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## (LIP6), département Systèmes Répartis Coopératifs (SRC), Université
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@ -42,6 +42,7 @@ twaalgos_HEADERS = \
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contains.hh \
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copy.hh \
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cycles.hh \
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dbranch.hh \
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degen.hh \
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determinize.hh \
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dot.hh \
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@ -115,6 +116,7 @@ libtwaalgos_la_SOURCES = \
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compsusp.cc \
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contains.cc \
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cycles.cc \
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dbranch.cc \
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degen.cc \
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determinize.cc \
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dot.cc \
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163
spot/twaalgos/dbranch.cc
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163
spot/twaalgos/dbranch.cc
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@ -0,0 +1,163 @@
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// -*- coding: utf-8 -*-
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// Copyright (C) 2022 Laboratoire de Recherche et Développement
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// de l'Epita (LRDE).
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//
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// This file is part of Spot, a model checking library.
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//
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// Spot is free software; you can redistribute it and/or modify it
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// under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 3 of the License, or
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// (at your option) any later version.
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//
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// Spot is distributed in the hope that it will be useful, but WITHOUT
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// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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// or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
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// License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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#include "config.h"
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#include <spot/twaalgos/dbranch.hh>
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#include <spot/misc/bddlt.hh>
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#include <spot/priv/robin_hood.hh>
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#include <unordered_map>
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#include <utility>
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#include <stack>
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namespace spot
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{
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namespace
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{
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typedef std::pair<bdd, acc_cond::mark_t> bdd_color;
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struct bdd_color_hash
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{
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size_t
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operator()(const bdd_color& bc) const noexcept
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{
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return bc.first.id() ^ bc.second.hash();
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}
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};
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template<bool is_game>
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bool delay_branching_aux(const twa_graph_ptr& aut, std::vector<bool>* owner)
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{
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unsigned ns = aut->num_states();
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// number of predecessors of each state
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std::vector<unsigned> pred_count(ns, 0);
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unsigned init = aut->get_init_state_number();
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pred_count[init] = 2; // pretend the initial state has too many
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// predecessors, so it does not get fused.
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// for each state, number of successors that have a single predecessors
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std::vector<unsigned> succ_cand(ns, 0);
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for (auto& e: aut->edges())
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for (unsigned d: aut->univ_dests(e))
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{
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// Note that e.dst might be a destination group in
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// alternating automata.
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unsigned pc = ++pred_count[d];
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succ_cand[e.src] += (pc == 1) - (pc == 2);
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}
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bool changed = false;
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typedef robin_hood::unordered_map<bdd_color, unsigned,
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bdd_color_hash> hashmap_t;
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hashmap_t first_dest[1 + is_game];
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auto& g = aut->get_graph();
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// setup a DFS
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std::vector<bool> seen(ns);
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std::stack<unsigned> todo;
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auto push_state = [&](unsigned state)
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{
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todo.push(state);
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seen[state] = true;
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};
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push_state(init);
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while (!todo.empty())
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{
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unsigned src = todo.top();
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todo.pop();
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if (succ_cand[src] < 2) // nothing to merge
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{
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for (auto& e: aut->out(src))
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for (unsigned d: aut->univ_dests(e))
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if (!seen[d])
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push_state(d);
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continue;
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}
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first_dest[0].clear();
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if constexpr (is_game)
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first_dest[1].clear();
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auto it = g.out_iteraser(src);
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while (it)
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{
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unsigned canddst = it->dst;
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for (unsigned d: aut->univ_dests(canddst))
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if (!seen[d])
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push_state(d);
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if (aut->is_univ_dest(canddst) || pred_count[canddst] != 1)
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{
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++it;
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continue;
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}
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if (it->cond == bddfalse)
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{
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it.erase();
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continue;
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}
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unsigned mapidx = is_game ? (*owner)[canddst] : 0;
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auto [it2, inserted] =
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first_dest[mapidx].emplace(bdd_color{it->cond, it->acc},
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canddst);
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if (inserted)
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{
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++it;
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continue;
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}
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unsigned mergedst = it2->second;
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// we have to merge canddst into mergedst. This is as
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// simple as:
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// 1) connecting their list of transitions
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unsigned& mergedfirst = g.state_storage(mergedst).succ;
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unsigned& mergedlast = g.state_storage(mergedst).succ_tail;
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unsigned& candfirst = g.state_storage(canddst).succ;
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unsigned& candlast = g.state_storage(canddst).succ_tail;
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if (mergedlast)
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aut->edge_storage(mergedlast).next_succ = candfirst;
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else // mergedst had now successor
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mergedfirst = candfirst;
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mergedlast = candlast;
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// 2) updating the source of the merged transitions
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for (unsigned e2 = candfirst; e2 != 0;)
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{
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auto& edge = aut->edge_storage(e2);
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edge.src = mergedst;
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e2 = edge.next_succ;
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}
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// 3) deleting the edge to canddst.
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candfirst = candlast = 0;
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it.erase();
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// 4) updating succ_cand
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succ_cand[mergedst] += succ_cand[canddst];
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succ_cand[canddst] = 0;
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changed = true;
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}
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}
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return changed;
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}
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}
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bool delay_branching_here(const twa_graph_ptr& aut)
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{
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if (aut->prop_universal())
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return false;
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auto owner = aut->get_named_prop<std::vector<bool>>("state-player");
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if (SPOT_UNLIKELY(owner))
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return delay_branching_aux<true>(aut, owner);
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else
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return delay_branching_aux<false>(aut, nullptr);
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}
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}
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36
spot/twaalgos/dbranch.hh
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36
spot/twaalgos/dbranch.hh
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@ -0,0 +1,36 @@
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// -*- coding: utf-8 -*-
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// Copyright (C) 2022 Laboratoire de Recherche et Développement
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// de l'Epita (LRDE).
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//
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// This file is part of Spot, a model checking library.
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//
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// Spot is free software; you can redistribute it and/or modify it
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// under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 3 of the License, or
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// (at your option) any later version.
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//
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// Spot is distributed in the hope that it will be useful, but WITHOUT
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// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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// or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
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// License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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#pragma once
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#include <spot/twa/twagraph.hh>
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namespace spot
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{
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/// \ingroup twa_algorithms
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/// \brief Merge states to delay
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///
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/// If a state (x) has two outgoing transitions (x,l,m,y) and
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/// (x,l,m,z) going to states (x) and (y) that have no other
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/// incoming edges, then (y) and (z) can be merged (keeping the
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/// union of their outgoing destinations).
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///
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/// \return true iff the automaton was modified.
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SPOT_API bool delay_branching_here(const twa_graph_ptr& aut);
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}
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@ -1,5 +1,5 @@
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// -*- coding: utf-8 -*-
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// Copyright (C) 2013-2018, 2020-2021 Laboratoire de Recherche et
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// Copyright (C) 2013-2018, 2020-2022 Laboratoire de Recherche et
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// Développement de l'Epita (LRDE).
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//
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// This file is part of Spot, a model checking library.
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@ -29,6 +29,7 @@
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#include <spot/twaalgos/product.hh>
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#include <spot/twaalgos/sccinfo.hh>
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#include <spot/twaalgos/hoa.hh>
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#include <spot/twaalgos/dbranch.hh>
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namespace spot
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{
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aut = ltl_to_tgba_fm(r, simpl_->get_dict(), exprop,
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true, false, false, nullptr, nullptr,
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unambiguous);
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if (delay_branching_here(aut))
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{
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aut->purge_unreachable_states();
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aut->merge_edges();
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}
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}
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aut = this->postprocessor::run(aut, r);
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