1411fa6063
Fixes #50. * src/tgbaalgos/cycles.cc, src/tgbaalgos/cycles.hh: Rewrite using unsigned instead of state*, and std::vector instead of std::map. * src/tgbaalgos/isweakscc.cc, src/tgbaalgos/powerset.cc: Adjust.
120 lines
3 KiB
C++
120 lines
3 KiB
C++
// -*- coding: utf-8 -*-
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// Copyright (C) 2012, 2013, 2014, 2015 Laboratoire de Recherche et
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// Developpement 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 "cycles.hh"
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#include "ltlast/formula.hh"
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#include "isweakscc.hh"
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namespace spot
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{
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namespace
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{
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// Look for a non-accepting cycle.
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class weak_checker final : public enumerate_cycles
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{
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public:
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bool result;
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weak_checker(const scc_info& map)
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: enumerate_cycles(map), result(true)
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{
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}
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virtual bool
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cycle_found(unsigned start) override
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{
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dfs_stack::const_reverse_iterator i = dfs_.rbegin();
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acc_cond::mark_t acc = 0U;
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for (;;)
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{
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acc |= aut_->trans_storage(i->succ).acc;
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if (i->s == start)
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break;
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++i;
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// The const cast is here to please old g++ versions.
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// At least version 4.0 needs it.
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assert(i != const_cast<const dfs_stack&>(dfs_).rend());
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}
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if (!aut_->acc().accepting(acc))
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{
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// We have found an non-accepting cycle, so the SCC is not
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// weak.
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result = false;
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return false;
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}
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return true;
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}
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};
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}
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bool
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is_inherently_weak_scc(scc_info& map, unsigned scc)
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{
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// If no cycle is accepting, the SCC is weak.
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if (!map.is_accepting_scc(scc))
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return true;
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// If the SCC is accepting, but one cycle is not, the SCC is not
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// weak.
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weak_checker w(map);
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w.run(scc);
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return w.result;
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}
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bool
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is_weak_scc(scc_info& map, unsigned scc)
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{
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// If no cycle is accepting, the SCC is weak.
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if (!map.is_accepting_scc(scc))
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return true;
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// If all transitions use the same acceptance set, the SCC is weak.
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return map.used_acc_of(scc).size() == 1;
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}
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bool
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is_complete_scc(scc_info& map, unsigned scc)
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{
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auto a = map.get_aut();
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for (auto s: map.states_of(scc))
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{
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bool has_succ = false;
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bdd sumall = bddfalse;
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for (auto& t: a->out(s))
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{
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has_succ = true;
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if (map.scc_of(t.dst) == scc)
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sumall |= t.cond;
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if (sumall == bddtrue)
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break;
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}
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if (!has_succ || sumall != bddtrue)
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return false;
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}
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return true;
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}
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bool
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is_terminal_scc(scc_info& map, unsigned scc)
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{
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// If all transitions use all acceptance conditions, the SCC is weak.
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return (map.is_accepting_scc(scc)
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&& map.used_acc_of(scc).size() == 1
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&& is_complete_scc(map, scc));
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}
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}
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