964f856bb5
accepting runs for ndfs emptiness check algoritms. * src/tgbaalgos/Makefile.am: Add it. * src/tgbaalgos/magic.cc, src/tgbaalgos/se05.cc, src/tgbaalgos/tau03.cc, src/tgbaalgos/tau03opt.cc: Remove the old result classes and use the new one.
338 lines
11 KiB
C++
338 lines
11 KiB
C++
// Copyright (C) 2004 Laboratoire d'Informatique de Paris 6 (LIP6),
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// département Systèmes Répartis Coopératifs (SRC), Université Pierre
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// et Marie Curie.
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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 2 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 Spot; see the file COPYING. If not, write to the Free
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// Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
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// 02111-1307, USA.
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#ifndef SPOT_TGBAALGOS_NDFS_RESULT_HH
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# define SPOT_TGBAALGOS_NDFS_RESULT_HH
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#include <cassert>
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#include <list>
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#include "tgba/tgba.hh"
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#include "emptiness.hh"
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#include "emptiness_stats.hh"
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#include "bfssteps.hh"
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/// FIXME:
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/// * Add the necessary calls to pop_notify.
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namespace spot
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{
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struct stack_item
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{
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stack_item(const state* n, tgba_succ_iterator* i, bdd l, bdd a)
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: s(n), it(i), label(l), acc(a) {};
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/// The visited state.
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const state* s;
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/// Design the next successor of \a s which has to be visited.
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tgba_succ_iterator* it;
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/// The label of the transition traversed to reach \a s
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/// (false for the first one).
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bdd label;
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/// The acceptance set of the transition traversed to reach \a s
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/// (false for the first one).
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bdd acc;
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};
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typedef std::list<stack_item> stack_type;
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template < typename ndfs_search, typename heap >
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class ndfs_result : public emptiness_check_result
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{
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public:
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ndfs_result(const ndfs_search& ms)
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: emptiness_check_result(ms.automaton()), ms_(ms), h_(ms_.get_heap())
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{
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}
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virtual ~ndfs_result()
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{
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while (!st1.empty())
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{
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delete st1.front().it;
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st1.pop_front();
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}
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}
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virtual tgba_run* accepting_run()
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{
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const stack_type& stb = ms_.get_st_blue();
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const stack_type& str = ms_.get_st_red();
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assert(!stb.empty());
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tgba_run* run = new tgba_run;
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const state* target = str.empty()?stb.front().s:str.front().s;
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bdd covered_acc = bddfalse;
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typename stack_type::const_reverse_iterator i, j;
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i = j = stb.rbegin(); ++j;
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for (; i->s->compare(target) != 0; ++i, ++j)
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{
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tgba_run::step s = { i->s->clone(), j->label, j->acc };
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run->prefix.push_back(s);
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}
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if (!str.empty())
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{
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typename stack_type::const_reverse_iterator end = stb.rend();
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for (; j != end; ++i, ++j)
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{
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covered_acc |= j->acc;
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tgba_run::step s = { i->s->clone(), j->label, j->acc };
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run->cycle.push_back(s);
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}
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j = str.rbegin();
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covered_acc |= j->acc;
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tgba_run::step s = { i->s->clone(), j->label, j->acc };
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run->cycle.push_back(s);
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i = j; ++j;
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end = str.rend();
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for (; j != end; ++i, ++j)
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{
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covered_acc |= j->acc;
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tgba_run::step s = { i->s->clone(), j->label, j->acc };
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run->cycle.push_back(s);
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}
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}
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if (a_->all_acceptance_conditions() != covered_acc)
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{
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// try if any to minimize the first loop in run->cycle ??
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// what transitions have to be preserved (it depend on
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// the detection (in the blue or red dfs) ??
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tgba_succ_iterator* i = a_->succ_iter(target);
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i->first();
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st1.push_front(stack_item(target, i, bddfalse, bddfalse));
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bool b = dfs(target, run->cycle, covered_acc);
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assert(b);
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(void)b;
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while (!st1.empty())
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{
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delete st1.front().it;
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st1.pop_front();
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}
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}
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return run;
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}
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private:
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const ndfs_search& ms_;
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const heap& h_;
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stack_type st1;
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typedef Sgi::hash_set<const state*,
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state_ptr_hash, state_ptr_equal> state_set;
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class shortest_path: public bfs_steps
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{
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public:
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shortest_path(const tgba* a, const state* t,
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const state_set& d, const heap& h)
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: bfs_steps(a), target(t), dead(d), h(h)
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{
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}
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~shortest_path()
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{
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}
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const state*
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search(const state* start, tgba_run::steps& l)
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{
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const state* s = filter(start);
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if (s)
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return this->bfs_steps::search(s, l);
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else
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return 0;
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}
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const state*
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filter(const state* s)
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{
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if (!h.has_been_visited(s))
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{
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delete s;
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return 0;
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}
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if (dead.find(s) != dead.end())
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return 0;
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seen.insert(s);
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return s;
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}
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const state_set&
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get_seen() const
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{
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return seen;
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}
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bool
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match(tgba_run::step&, const state* dest)
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{
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return target->compare(dest) == 0;
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}
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private:
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state_set seen;
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const state* target;
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const state_set& dead;
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const heap& h;
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};
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void complete_cycle(tgba_run::steps& cycle, bdd& covered_acc,
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const tgba_run::step& start, tgba_run::steps& path,
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const state_set& dead)
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{
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tgba_run::steps new_cycle;
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// find the minimal path between st1.back().s and st1.front().s
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if (st1.back().s->compare(st1.front().s)!=0)
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{
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shortest_path s(a_, st1.front().s, dead, h_);
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const state* res = s.search(st1.back().s, new_cycle);
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assert(res && res->compare(st1.front().s) == 0);
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(void)res;
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for (tgba_run::steps::const_iterator it = new_cycle.begin();
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it != new_cycle.end(); ++it)
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covered_acc |= it->acc;
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}
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// traverse the accepting transition
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covered_acc |= start.acc;
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tgba_run::step s = { st1.front().s->clone(), start.label, start.acc };
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new_cycle.push_back(s);
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// follow the minimal path returning to st1.back().s
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for (tgba_run::steps::const_iterator it = path.begin();
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it != path.end(); ++it)
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covered_acc |= it->acc;
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new_cycle.splice(new_cycle.end(), path);
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// concat this new loop to the existing ones
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cycle.splice(cycle.end(), new_cycle);
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}
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bool dfs(const state* target, tgba_run::steps& cycle, bdd& covered_acc)
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{
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state_set seen, dead;
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seen.insert(target);
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while (!st1.empty())
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{
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stack_item& f = st1.front();
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trace << "DFS1 treats: " << a_->format_state(f.s) << std::endl;
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if (!f.it->done())
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{
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const state *s_prime = f.it->current_state();
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trace << " Visit the successor: "
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<< a_->format_state(s_prime) << std::endl;
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bdd label = f.it->current_condition();
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bdd acc = f.it->current_acceptance_conditions();
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f.it->next();
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if (h_.has_been_visited(s_prime))
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{
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if (dead.find(s_prime) != dead.end())
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{
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trace << " it is dead, pop it" << std::endl;
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}
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else if (seen.find(s_prime) == seen.end())
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{
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trace << " it is not seen, go down" << std::endl;
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seen.insert(s_prime);
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tgba_succ_iterator* i = a_->succ_iter(s_prime);
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i->first();
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st1.push_front(stack_item(s_prime, i, label, acc));
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}
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else if ((acc & covered_acc) != acc)
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{
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trace << " a propagation is needed, start a search"
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<< std::endl;
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tgba_run::step s = {s_prime, label, acc};
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if (search(s, target, dead, cycle, covered_acc))
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return true;
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}
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else
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{
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trace << " already seen, pop it" << std::endl;
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}
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}
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else
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delete s_prime;
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}
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else
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{
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trace << " all the successors have been visited"
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<< std::endl;
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stack_item f_dest(f);
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delete st1.front().it;
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st1.pop_front();
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if (!st1.empty() && (f_dest.acc & covered_acc) != f_dest.acc)
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{
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trace << " a propagation is needed, start a search"
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<< std::endl;
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tgba_run::step s = {f_dest.s,
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f_dest.label,
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f_dest.acc};
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if (search(s, target, dead, cycle, covered_acc))
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return true;
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}
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else
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{
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trace << " no propagation needed, pop it" << std::endl;
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}
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}
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}
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return false;
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}
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bool search(const tgba_run::step& start, const state* target,
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state_set& dead, tgba_run::steps& cycle, bdd& covered_acc)
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{
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tgba_run::steps path;
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if (start.s->compare(target)==0)
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{
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trace << " complete the cycle" << std::endl;
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complete_cycle(cycle, covered_acc, start, path, dead);
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return covered_acc == a_->all_acceptance_conditions();
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}
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shortest_path s(a_, target, dead, h_);
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const state* res = s.search(start.s, path);
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if (res)
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{
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assert(res->compare(target) == 0);
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trace << " complete the cycle" << std::endl;
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complete_cycle(cycle, covered_acc, start, path, dead);
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return covered_acc == a_->all_acceptance_conditions();
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}
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state_set::const_iterator it;
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for (it = s.get_seen().begin(); it != s.get_seen().end(); ++it)
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dead.insert(*it);
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return false;
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}
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};
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}
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#endif // SPOT_TGBAALGOS_NDFS_RESULT_HH
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