9909699c63
* src/tgbaalgos/sccfilter.cc, src/tgbaalgos/sccfilter.hh (scc_filter_states): New overload taking a tgba_digraph and some scc_info.
658 lines
18 KiB
C++
658 lines
18 KiB
C++
// -*- coding: utf-8 -*-
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// Copyright (C) 2009, 2010, 2011, 2012, 2013, 2014 Laboratoire de
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// Recherche et 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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//
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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 "tgba/tgbaexplicit.hh"
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#include "sccfilter.hh"
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#include "reachiter.hh"
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#include "tgbaalgos/scc.hh"
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#include "tgbaalgos/sccinfo.hh"
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namespace spot
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{
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namespace
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{
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// BDD.id -> Acc number
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typedef std::map<int, unsigned> accremap_t;
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typedef std::vector<accremap_t> remap_table_t;
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static
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state_explicit_number::transition*
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create_transition(const tgba*, tgba_explicit_number* out_aut,
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const state*, int in, const state*, int out)
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{
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return out_aut->create_transition(in, out);
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}
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static
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state_explicit_string::transition*
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create_transition(const tgba* aut, tgba_explicit_string* out_aut,
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const state* in_s, int, const state* out_s, int)
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{
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const tgba_explicit_string* a =
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static_cast<const tgba_explicit_string*>(aut);
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return out_aut->create_transition(a->get_label(in_s),
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a->get_label(out_s));
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}
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static
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state_explicit_formula::transition*
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create_transition(const tgba* aut, tgba_explicit_formula* out_aut,
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const state* in_s, int, const state* out_s, int)
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{
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const tgba_explicit_formula* a =
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static_cast<const tgba_explicit_formula*>(aut);
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const ltl::formula* in_f = a->get_label(in_s);
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const ltl::formula* out_f = a->get_label(out_s);
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if (!out_aut->has_state(in_f))
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in_f->clone();
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if ((in_f != out_f) && !out_aut->has_state(out_f))
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out_f->clone();
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return out_aut->create_transition(in_f, out_f);
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}
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template<class T>
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class filter_iter_states: public tgba_reachable_iterator_depth_first
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{
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public:
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typedef T output_t;
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filter_iter_states(const tgba* a,
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const scc_map& sm,
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const std::vector<bool>& useless)
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: tgba_reachable_iterator_depth_first(a),
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out_(new T(a->get_dict())),
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sm_(sm),
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useless_(useless)
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{
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a->get_dict()->register_all_variables_of(a, out_);
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out_->set_acceptance_conditions(a->all_acceptance_conditions());
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}
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T*
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result()
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{
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return out_;
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}
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bool
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want_state(const state* s) const
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{
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return !useless_[sm_.scc_of_state(s)];
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}
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void
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process_link(const state* in_s, int in,
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const state* out_s, int out,
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const tgba_succ_iterator* si)
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{
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typename output_t::state::transition* t =
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create_transition(this->aut_, out_, in_s, in, out_s, out);
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t->condition = si->current_condition();
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t->acceptance_conditions = si->current_acceptance_conditions();
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}
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protected:
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T* out_;
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const scc_map& sm_;
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const std::vector<bool>& useless_;
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};
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template<class T>
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class filter_iter: public tgba_reachable_iterator_depth_first
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{
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public:
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typedef T output_t;
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typedef std::map<int, bdd> map_t;
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typedef std::vector<map_t> remap_t;
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filter_iter(const tgba* a,
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const scc_map& sm,
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const std::vector<bool>& useless,
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remap_table_t& remap_table,
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unsigned max_num,
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bool remove_all_useless)
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: tgba_reachable_iterator_depth_first(a),
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out_(new T(a->get_dict())),
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sm_(sm),
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useless_(useless),
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all_(remove_all_useless),
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acc_(max_num)
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{
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acc_[0] = bddfalse;
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bdd tmp = a->all_acceptance_conditions();
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bdd_dict* d = a->get_dict();
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assert(a->number_of_acceptance_conditions() >= max_num - 1);
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if (tmp != bddfalse)
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{
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for (unsigned n = max_num - 1; n > 0; --n)
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{
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assert(tmp != bddfalse);
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const ltl::formula* a = d->oneacc_to_formula(bdd_var(tmp));
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out_->declare_acceptance_condition(a->clone());
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tmp = bdd_low(tmp);
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}
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tmp = a->all_acceptance_conditions();
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for (unsigned n = max_num - 1; n > 0; --n)
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{
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const ltl::formula* a = d->oneacc_to_formula(bdd_var(tmp));
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acc_[n] = out_->get_acceptance_condition(a->clone());
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tmp = bdd_low(tmp);
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}
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}
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else
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{
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assert(max_num == 1);
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}
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unsigned c = sm.scc_count();
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remap_.resize(c);
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bdd all_orig_neg = aut_->neg_acceptance_conditions();
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bdd all_sup = bdd_support(all_orig_neg);
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for (unsigned n = 0; n < c; ++n)
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{
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//std::cerr << "SCC #" << n << '\n';
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if (!sm.accepting(n))
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continue;
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bdd all = sm.useful_acc_of(n);
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while (all != bddfalse)
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{
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bdd one = bdd_satoneset(all, all_sup, bddtrue);
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all -= one;
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bdd res = bddfalse;
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bdd resacc = bddfalse;
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while (one != bddtrue)
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{
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if (bdd_high(one) == bddfalse)
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{
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one = bdd_low(one);
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continue;
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}
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int vn = bdd_var(one);
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bdd v = bdd_ithvar(vn);
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resacc |= bdd_exist(all_orig_neg, v) & v;
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res |= acc_[remap_table[n][vn]];
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one = bdd_high(one);
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}
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int id = resacc.id();
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//std::cerr << resacc << " -> " << res << '\n';
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remap_[n][id] = res;
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}
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}
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}
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T*
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result()
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{
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return out_;
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}
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bool
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want_state(const state* s) const
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{
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return !useless_[sm_.scc_of_state(s)];
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}
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void
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process_link(const state* in_s, int in,
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const state* out_s, int out,
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const tgba_succ_iterator* si)
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{
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typename output_t::state::transition* t =
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create_transition(this->aut_, out_, in_s, in, out_s, out);
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out_->add_conditions(t, si->current_condition());
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// Regardless of all_, do not output any acceptance condition
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// if the destination is not in an accepting SCC.
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//
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// If all_ is set, do not output any acceptance condition if the
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// source is not in the same SCC as dest.
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//
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// (See the documentation of scc_filter() for a rational.)
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unsigned u = sm_.scc_of_state(out_s);
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unsigned v = sm_.scc_of_state(in_s);
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if (sm_.accepting(u) && (!all_ || u == v))
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{
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bdd acc = si->current_acceptance_conditions();
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if (acc == bddfalse)
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return;
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map_t::const_iterator i = this->remap_[u].find(acc.id());
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if (i != this->remap_[u].end())
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{
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t->acceptance_conditions = i->second;
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}
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else
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{
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//t->acceptance_conditions = this->remap_[v][acc.id()];
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}
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}
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}
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protected:
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T* out_;
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const scc_map& sm_;
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const std::vector<bool>& useless_;
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bool all_;
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std::vector<bdd> acc_;
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remap_t remap_;
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};
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template<class T>
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class filter_iter_susp: public filter_iter<T>
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{
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public:
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typedef filter_iter<T> super;
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filter_iter_susp(const tgba* a,
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const scc_map& sm,
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const std::vector<bool>& useless,
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remap_table_t& remap_table,
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unsigned max_num,
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bool remove_all_useless,
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bdd susp_pos, bool early_susp, bdd ignored)
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: super(a, sm, useless, remap_table, max_num, remove_all_useless),
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susp_pos(susp_pos), early_susp(early_susp), ignored(ignored)
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{
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}
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void
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process_link(const state* in_s, int in,
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const state* out_s, int out,
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const tgba_succ_iterator* si)
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{
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unsigned u = this->sm_.scc_of_state(out_s);
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unsigned v = this->sm_.scc_of_state(in_s);
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bool destacc = this->sm_.accepting(u);
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typename super::output_t::state::transition* t =
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create_transition(this->aut_, this->out_, in_s, in, out_s, out);
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bdd cond = bdd_exist(si->current_condition(), ignored);
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// Remove suspended variables on transitions going to
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// non-accepting SCC, or on transition between SCC unless
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// early_susp is set.
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if (!destacc || (!early_susp && (u != this->sm_.scc_of_state(in_s))))
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cond = bdd_exist(cond, susp_pos);
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this->out_->add_conditions(t, cond);
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// Regardless of all_, do not output any acceptance condition
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// if the destination is not in an accepting SCC.
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//
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// If all_ is set, do not output any acceptance condition if the
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// source is not in the same SCC as dest.
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//
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// (See the documentation of scc_filter() for a rational.)
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if (destacc && (!this->all_ || u == v))
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{
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bdd acc = si->current_acceptance_conditions();
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if (acc == bddfalse)
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return;
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typename super::map_t::const_iterator i =
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this->remap_[u].find(acc.id());
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if (i != this->remap_[u].end())
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{
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t->acceptance_conditions = i->second;
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}
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else
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{
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// t->acceptance_conditions = this->remap_[v][acc.id()];
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}
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}
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}
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protected:
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bdd susp_pos;
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bool early_susp;
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bdd ignored;
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};
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} // anonymous
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tgba* scc_filter(const tgba* aut, bool remove_all_useless,
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scc_map* given_sm, bdd susp, bool early_susp, bdd ignored)
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{
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scc_map* sm = given_sm;
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if (!sm)
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{
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sm = new scc_map(aut);
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sm->build_map();
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}
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scc_stats ss = build_scc_stats(*sm);
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remap_table_t remap_table(ss.scc_total);
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std::vector<unsigned> max_table(ss.scc_total);
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std::vector<bdd> useful_table(ss.scc_total);
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std::vector<bdd> useless_table(ss.scc_total);
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unsigned max_num = 1;
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for (unsigned n = 0; n < ss.scc_total; ++n)
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{
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if (!sm->accepting(n))
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continue;
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bdd all = sm->useful_acc_of(n);
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bdd negall = aut->neg_acceptance_conditions();
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//std::cerr << "SCC #" << n << "; used = " << all << std::endl;
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// Compute a set of useless acceptance sets.
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// If the acceptance combinations occurring in
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// the automata are { a, ab, abc, bd }, then
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// ALL contains (a&!b&!c&!d)|(a&b&!c&!d)|(a&b&c&!d)|(!a&b&!c&d)
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// and we want to find that 'a' and 'b' are useless because
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// they always occur with 'c'.
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// The way we check if 'a' is useless is to look whether ALL
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// implies (x -> a) for some other acceptance set x.
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//
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// The two while() loops in the code perform the equivalent of
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// for all a in allconds_a:
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// for all x in allconds_x:
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// check whether x -> a
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// ...
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//
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// Initially allconds_a = allconds_x contains all acceptance
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// sets. However when an acceptance set 'a' is determined to
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// be useless, it can be removed from allconds_x from future
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// iterations.
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bdd allconds_a = bdd_support(negall);
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bdd allconds_x = allconds_a;
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bdd useless = bddtrue;
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while (allconds_a != bddtrue)
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{
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// Speed-up the computation of implied acceptance sets by
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// removing those that are always present. We detect
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// those that appear as conjunction of positive variables
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// at the start of ALL.
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bdd prefix = bdd_satprefix(all);
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if (prefix != bddtrue)
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{
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assert(prefix == bdd_support(prefix));
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allconds_a = bdd_exist(allconds_a, prefix);
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if (allconds_a != bddtrue)
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{
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useless &= prefix;
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}
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else
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{
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// Never erase all conditions: at least keep one.
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useless &= bdd_high(prefix);
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break;
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}
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allconds_x = bdd_exist(allconds_x, prefix);
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}
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// Pick an acceptance set 'a'.
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bdd a = bdd_ithvar(bdd_var(allconds_a));
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// For all acceptance sets 'x' that are not already
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// useless...
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bdd others = allconds_x;
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while (others != bddtrue)
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{
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bdd x = bdd_ithvar(bdd_var(others));
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// ... check whether 'x' always implies 'a'.
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if (x != a && bdd_implies(all, x >> a))
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{
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// If so, 'a' is useless.
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all = bdd_exist(all, a);
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useless &= a;
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allconds_x = bdd_exist(allconds_x, a);
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break;
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}
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others = bdd_high(others);
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}
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allconds_a = bdd_high(allconds_a);
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}
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// We never remove ALL acceptance marks.
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assert(negall == bddtrue || useless != bdd_support(negall));
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useless_table[n] = useless;
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bdd useful = bdd_exist(negall, useless);
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//std::cerr << "SCC #" << n << "; useful = " << useful << std::endl;
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// Go over all useful sets of acceptance marks, and give them
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// a number.
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unsigned num = 1;
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// First compute the number of acceptance conditions used.
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for (BDD c = useful.id(); c != 1; c = bdd_low(c))
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++num;
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max_table[n] = num;
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if (num > max_num)
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max_num = num;
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useful_table[n] = useful;
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}
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// Now that we know about the max number of acceptance conditions,
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// use add extra acceptance conditions to those SCC that do not
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// have enough.
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for (unsigned n = 0; n < ss.scc_total; ++n)
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{
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if (!sm->accepting(n))
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continue;
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//std::cerr << "SCC " << n << '\n';
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bdd useful = useful_table[n];
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int missing = max_num - max_table[n];
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bdd useless = useless_table[n];
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while (missing--)
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{
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//std::cerr << useful << " : " << useless << std::endl;
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useful &= bdd_nithvar(bdd_var(useless));
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useless = bdd_high(useless);
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}
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int num = max_num;
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// Then number all of these acceptance conditions in the
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// reverse order. This makes sure that the associated number
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// varies in the same direction as the bdd variables, which in
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// turn makes sure we preserve the acceptance condition
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// ordering (which matters for degeneralization).
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for (BDD c = useful.id(); c != 1; c = bdd_low(c))
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remap_table[n].insert(std::make_pair(bdd_var(c), --num));
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max_table[n] = max_num;
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}
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tgba* ret;
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// In most cases we will create a tgba_explicit_string copy of the
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// initial tgba, but this is not very space efficient as the
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// labels are built using the "format_state()" string output of
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// the original automaton. In the case where the source automaton is
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// a tgba_explicit_formula (typically after calling ltl2tgba_fm())
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// we can create another tgba_explicit_formula instead.
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const tgba_explicit_formula* af =
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dynamic_cast<const tgba_explicit_formula*>(aut);
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if (af)
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{
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if (susp == bddtrue)
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{
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filter_iter<tgba_explicit_formula> fi(af, *sm,
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ss.useless_scc_map,
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remap_table, max_num,
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remove_all_useless);
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fi.run();
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tgba_explicit_formula* res = fi.result();
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res->merge_transitions();
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ret = res;
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}
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else
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{
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filter_iter_susp<tgba_explicit_formula> fi(af, *sm,
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ss.useless_scc_map,
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remap_table, max_num,
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remove_all_useless,
|
|
susp, early_susp,
|
|
ignored);
|
|
fi.run();
|
|
tgba_explicit_formula* res = fi.result();
|
|
res->merge_transitions();
|
|
ret = res;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
const tgba_explicit_string* as =
|
|
dynamic_cast<const tgba_explicit_string*>(aut);
|
|
if (as)
|
|
{
|
|
filter_iter<tgba_explicit_string> fi(aut, *sm, ss.useless_scc_map,
|
|
remap_table, max_num,
|
|
remove_all_useless);
|
|
fi.run();
|
|
tgba_explicit_string* res = fi.result();
|
|
res->merge_transitions();
|
|
ret = res;
|
|
}
|
|
else
|
|
{
|
|
if (susp == bddtrue)
|
|
{
|
|
filter_iter<tgba_explicit_number> fi(aut, *sm,
|
|
ss.useless_scc_map,
|
|
remap_table, max_num,
|
|
remove_all_useless);
|
|
fi.run();
|
|
tgba_explicit_number* res = fi.result();
|
|
res->merge_transitions();
|
|
ret = res;
|
|
}
|
|
else
|
|
{
|
|
filter_iter_susp<tgba_explicit_number> fi(aut, *sm,
|
|
ss.useless_scc_map,
|
|
remap_table, max_num,
|
|
remove_all_useless,
|
|
susp, early_susp,
|
|
ignored);
|
|
fi.run();
|
|
tgba_explicit_number* res = fi.result();
|
|
res->merge_transitions();
|
|
ret = res;
|
|
}
|
|
}
|
|
}
|
|
if (!given_sm)
|
|
delete sm;
|
|
return ret;
|
|
}
|
|
|
|
tgba* scc_filter_states(const tgba* aut, scc_map* given_sm)
|
|
{
|
|
const tgba_digraph* autg = dynamic_cast<const tgba_digraph*>(aut);
|
|
if (autg && !given_sm)
|
|
return scc_filter_states(autg, nullptr);
|
|
|
|
scc_map* sm = given_sm;
|
|
if (!sm)
|
|
{
|
|
sm = new scc_map(aut);
|
|
sm->build_map();
|
|
}
|
|
scc_stats ss = build_scc_stats(*sm);
|
|
|
|
tgba* ret;
|
|
|
|
const tgba_explicit_formula* af =
|
|
dynamic_cast<const tgba_explicit_formula*>(aut);
|
|
if (af)
|
|
{
|
|
filter_iter_states<tgba_explicit_formula> fi(af, *sm,
|
|
ss.useless_scc_map);
|
|
fi.run();
|
|
tgba_explicit_formula* res = fi.result();
|
|
res->merge_transitions();
|
|
ret = res;
|
|
}
|
|
else
|
|
{
|
|
const tgba_explicit_string* as =
|
|
dynamic_cast<const tgba_explicit_string*>(aut);
|
|
if (as)
|
|
{
|
|
filter_iter_states<tgba_explicit_string> fi(aut, *sm,
|
|
ss.useless_scc_map);
|
|
fi.run();
|
|
tgba_explicit_string* res = fi.result();
|
|
res->merge_transitions();
|
|
ret = res;
|
|
}
|
|
else
|
|
{
|
|
filter_iter_states<tgba_explicit_number> fi(aut, *sm,
|
|
ss.useless_scc_map);
|
|
fi.run();
|
|
tgba_explicit_number* res = fi.result();
|
|
res->merge_transitions();
|
|
ret = res;
|
|
}
|
|
}
|
|
if (!given_sm)
|
|
delete sm;
|
|
return ret;
|
|
}
|
|
|
|
tgba_digraph* scc_filter_states(const tgba_digraph* aut, scc_info* given_si)
|
|
{
|
|
// Compute scc_info if not supplied.
|
|
scc_info* si = given_si;
|
|
if (!si)
|
|
si = new scc_info(aut);
|
|
|
|
// Renumber all useful states.
|
|
unsigned in_n = aut->num_states(); // Number of input states.
|
|
unsigned out_n = 0; // Number of output states.
|
|
std::vector<unsigned> inout; // Associate old states to new ones.
|
|
inout.reserve(in_n);
|
|
for (unsigned i = 0; i < in_n; ++i)
|
|
if (si->is_useful_state(i))
|
|
inout.push_back(out_n++);
|
|
else
|
|
inout.push_back(-1U);
|
|
|
|
// scc_info is not useful anymore.
|
|
if (!given_si)
|
|
delete si;
|
|
|
|
bdd_dict* bd = aut->get_dict();
|
|
tgba_digraph* filtered = new tgba_digraph(bd);
|
|
bd->register_all_variables_of(aut, filtered);
|
|
filtered->copy_acceptance_conditions_of(aut);
|
|
const tgba_digraph::graph_t& ing = aut->get_graph();
|
|
tgba_digraph::graph_t& outg = filtered->get_graph();
|
|
outg.new_states(out_n);
|
|
for (unsigned isrc = 0; isrc < in_n; ++isrc)
|
|
{
|
|
unsigned osrc = inout[isrc];
|
|
if (osrc >= out_n)
|
|
continue;
|
|
for (auto& t: ing.out(isrc))
|
|
{
|
|
unsigned odst = inout[t.dst];
|
|
if (odst >= out_n)
|
|
continue;
|
|
outg.new_transition(osrc, odst, t.cond, t.acc);
|
|
}
|
|
}
|
|
filtered->set_init_state(aut->get_init_state_number());
|
|
return filtered;
|
|
}
|
|
|
|
}
|