Introduce compositional suspension (SPIN'13)
* src/tgbaalgos/compsusp.cc, src/tgbaalgos/compsusp.hh: New files. * src/tgbaalgos/Makefile.am: Add them. * src/tgbaalgos/sccfilter.cc, src/tgbaalgos/sccfilter.hh: Add option for suspended labels removal. * src/tgbatest/ltl2tgba.cc, src/tgbatest/spotlbtt.test: Test it.
This commit is contained in:
Alexandre Duret-Lutz
parent
ba6fe9e183
commit
53c6923567
7 changed files with 741 additions and 38 deletions
441
src/tgbaalgos/compsusp.cc
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441
src/tgbaalgos/compsusp.cc
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// -*- coding: utf-8 -*-
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// Copyright (C) 2012, 2013 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 "compsusp.hh"
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#include "sccfilter.hh"
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#include "scc.hh"
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#include "tgba/tgbaexplicit.hh"
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#include "ltl2tgba_fm.hh"
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#include "minimize.hh"
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#include "simulation.hh"
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#include "safety.hh"
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#include "ltlast/allnodes.hh"
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#include "ltlvisit/tostring.hh"
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#include "ltlvisit/clone.hh"
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#include <queue>
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#include <sstream>
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#include "ltlenv/environment.hh"
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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::map<const ltl::formula*, bdd> formula_bdd_map;
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// An environment to store atomic proposition associated to
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// suspended variable. (We don't use the default environment to
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// avoid conflicts with user-defined atomic propositions that
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// would share the same name.)
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class suspended_environment: public ltl::environment
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{
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public:
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const ltl::formula*
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require(const std::string& s)
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{
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return ltl::atomic_prop::instance(s, *this);
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}
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const std::string&
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name()
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{
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static std::string name("suspended environment");
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return name;
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}
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};
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static suspended_environment suspenv;
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// Rewrite the suspendable subformulae "s" of an LTL formula in
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// the form Gg where "g" is an atomic proposition representing
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// "s". At the same time, populate maps that associate "s" to "g"
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// and vice-versa.
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class ltl_suspender_visitor: public ltl::clone_visitor
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{
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public:
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typedef std::map<const ltl::formula*, const ltl::formula*> fmap_t;
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ltl_suspender_visitor(fmap_t& g2s, fmap_t& a2o, bool oblig)
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: g2s_(g2s), a2o_(a2o), oblig_(oblig)
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{
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}
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void
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visit(const ltl::multop* mo)
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{
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ltl::multop::type op = mo->op();
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switch (op)
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{
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case ltl::multop::Or:
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case ltl::multop::And:
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{
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ltl::multop::vec* res = new ltl::multop::vec;
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ltl::multop::vec* oblig = oblig_ ? new ltl::multop::vec : 0;
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ltl::multop::vec* susp = new ltl::multop::vec;
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unsigned mos = mo->size();
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for (unsigned i = 0; i < mos; ++i)
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{
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const ltl::formula* c = mo->nth(i);
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if (c->is_boolean())
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res->push_back(c->clone());
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else if (oblig_ && c->is_syntactic_obligation())
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oblig->push_back(c->clone());
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else if (c->is_eventual() && c->is_universal())
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susp->push_back(c->clone());
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else
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res->push_back(recurse(c));
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}
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if (!oblig_ || oblig->empty())
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{
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delete oblig;
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}
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else
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{
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const ltl::formula* o = ltl::multop::instance(op, oblig);
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res->push_back(recurse(o));
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o->destroy();
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}
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if (susp->empty())
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{
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delete susp;
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}
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else
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{
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const ltl::formula* o = ltl::multop::instance(op, susp);
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// Rewrite 'o' as 'G"o"'
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const ltl::formula* g = recurse(o);
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o->destroy();
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if (op == ltl::multop::And)
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{
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res->push_back(g);
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}
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else
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{
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// res || susp -> (res && G![susp]) || G[susp])
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const ltl::formula* r = ltl::multop::instance(op, res);
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const ltl::unop* u =
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down_cast<const ltl::unop*>(g);
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const ltl::formula* gn =
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ltl::unop::instance
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(ltl::unop::G, ltl::unop::instance
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(ltl::unop::Not, u->child()->clone()));
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result_ = ltl::multop::instance
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(ltl::multop::Or, ltl::multop::instance
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(ltl::multop::And, r, gn),
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g);
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return;
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}
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}
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result_ = ltl::multop::instance(op, res);
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}
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break;
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case ltl::multop::OrRat:
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case ltl::multop::AndRat:
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case ltl::multop::AndNLM:
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case ltl::multop::Concat:
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case ltl::multop::Fusion:
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this->ltl::clone_visitor::visit(mo);
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break;
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}
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}
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const ltl::formula*
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recurse(const ltl::formula* f)
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{
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const ltl::formula* res;
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if (f->is_boolean())
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return f->clone();
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if (oblig_ && f->is_syntactic_obligation())
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{
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fmap_t::const_iterator i = assoc_.find(f);
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if (i != assoc_.end())
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return i->second->clone();
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std::ostringstream s;
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s << "〈";
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to_string(f, s);
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s << "〉";
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res = suspenv.require(s.str());
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// We have to clone f, because it is not always a sub-tree
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// of the original formula. (Think n-ary operators.)
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a2o_[res] = f->clone();
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assoc_[f] = res;
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return res;
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}
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if (f->is_eventual() && f->is_universal())
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{
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fmap_t::const_iterator i = assoc_.find(f);
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if (i != assoc_.end())
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return ltl::unop::instance(ltl::unop::G, i->second->clone());
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std::ostringstream s;
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s << "[";
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to_string(f, s);
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s << "]";
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res = suspenv.require(s.str());
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// We have to clone f, because it is not always a sub-tree
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// of the original formula. (Think n-ary operators.)
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g2s_[res] = f->clone();
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assoc_[f] = res;
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return ltl::unop::instance(ltl::unop::G, res);
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}
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f->accept(*this);
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return result_;
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}
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private:
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fmap_t& g2s_;
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fmap_t assoc_; // This one is only needed by the visitor.
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fmap_t& a2o_;
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bool oblig_;
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};
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typedef std::pair<const state*, const state*> state_pair;
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typedef std::map<state_pair, int> pair_map;
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typedef std::deque<state_pair> pair_queue;
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static
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tgba*
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susp_prod(tgba* left, const ltl::formula* f, bdd v)
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{
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bdd_dict* dict = left->get_dict();
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const tgba* a1 = ltl_to_tgba_fm(f, dict, true, true);
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const tgba* a2 = scc_filter(a1, false);
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delete a1;
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const tgba* right = iterated_simulations(a2);
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delete a2;
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tgba_explicit_number* res = new tgba_explicit_number(dict);
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dict->register_all_variables_of(left, res);
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dict->register_all_variables_of(right, res);
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dict->unregister_variable(bdd_var(v), res);
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// The left and right automata might have acceptance marker in
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// common.
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// For the example, assume left has acceptance conditions A,B,C,D
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// while right has acceptance condition C,D,E,F.
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// Negative acceptance variables...
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// !A&!B&!C&!D
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bdd lna = left->neg_acceptance_conditions();
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// !C&!D&!E&!F
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bdd rna = right->neg_acceptance_conditions();
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// Missing acceptance variables...
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// !E&!F
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bdd lma = bdd_exist(rna, bdd_support(lna));
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// !A&!B
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bdd rma = bdd_exist(lna, bdd_support(rna));
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// (A&!B&!C&!D + ... + !A&!B&!C&D) & !E&!F
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bdd lac = left->all_acceptance_conditions() & lma;
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// (C&!D&!E&!F + ... + !C&!D&!E&F) & !A&!B
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bdd rac = right->all_acceptance_conditions() & rma;
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bdd allacc = lac | rac;
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res->set_acceptance_conditions(allacc);
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// Acceptance condition to add to all transitions
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// of the left automaton.
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// !A&!B&!C&!D&E&!F | !A&!B&!C&!D&!E&F
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bdd ladd = rac - lma;
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bdd radd = lac - rma;
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pair_map seen;
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pair_queue todo;
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state_pair p(left->get_init_state(), 0);
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state* ris = right->get_init_state();
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p.second = ris;
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seen[p] = 0;
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todo.push_back(p);
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res->set_init_state(0);
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typedef state_explicit_number::transition trans;
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while (!todo.empty())
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{
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p = todo.front();
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todo.pop_front();
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const state* ls = p.first;
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const state* rs = p.second;
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int src = seen[p];
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tgba_succ_iterator* li = left->succ_iter(ls);
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for (li->first(); !li->done(); li->next())
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{
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state_pair d(li->current_state(), ris);
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bdd lc = li->current_condition();
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tgba_succ_iterator* ri = 0;
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// Should we reset the right automaton?
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if ((lc & v) == lc)
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{
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// No.
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ri = right->succ_iter(rs);
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ri->first();
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}
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// Yes. Reset the right automaton.
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else
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{
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p.second = ris;
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}
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// This loops over all the right transitions
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// if RI is defined. Otherwise this just makes
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// one iteration as if the right automaton was
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// looping in state 0 with "true".
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while (!ri || !ri->done())
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{
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bdd cond = lc;
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bdd ra = allacc;
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if (ri)
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{
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cond = lc & ri->current_condition();
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// Skip incompatible transitions.
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if (cond == bddfalse)
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{
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ri->next();
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continue;
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}
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d.second = ri->current_state();
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ra = (ri->current_acceptance_conditions() & rma) | radd;
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}
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int dest = seen.size();
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pair_map::const_iterator i = seen.find(d);
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if (i != seen.end())
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{
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dest = i->second;
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}
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else
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{
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seen[d] = dest;
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todo.push_back(d);
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}
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trans* t = res->create_transition(src, dest);
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t->condition = bdd_exist(cond, v);
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bdd la = (li->current_acceptance_conditions() & lma) | ladd;
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t->acceptance_conditions = ra & la;
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if (ri)
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ri->next();
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else
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break;
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}
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delete ri;
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}
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}
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delete left;
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delete right;
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return res;
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}
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}
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tgba*
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compsusp(const ltl::formula* f, bdd_dict* dict,
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bool no_wdba, bool no_simulation,
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bool early_susp, bool no_susp_product, bool wdba_smaller,
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bool oblig)
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{
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ltl_suspender_visitor::fmap_t g2s;
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ltl_suspender_visitor::fmap_t a2o;
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ltl_suspender_visitor v(g2s, a2o, oblig);
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const ltl::formula* g = v.recurse(f);
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tgba* res;
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{
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// Translate the patched formula, and remove useless SCCs.
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tgba* aut = spot::ltl_to_tgba_fm(g, dict, true, true, false, false, 0, 0);
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res = scc_filter(aut, false);
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delete aut;
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}
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if (!no_wdba)
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{
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tgba* min = minimize_obligation(res, g, 0, wdba_smaller);
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if (min != res)
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{
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delete res;
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res = min;
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no_simulation = true;
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}
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}
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if (!no_simulation)
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{
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tgba* sim = spot::iterated_simulations(res);
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delete res;
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res = sim;
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}
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spot::formula_bdd_map susp;
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ltl_suspender_visitor::fmap_t::const_iterator it;
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for (it = g2s.begin(); it != g2s.end(); ++it)
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{
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bdd_dict::fv_map::const_iterator j = dict->var_map.find(it->first);
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assert(j != dict->var_map.end());
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susp[it->second] = bdd_ithvar(j->second);
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}
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// Remove suspendable formulae from non-accepting SCCs.
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bdd suspvars = bddtrue;
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for (formula_bdd_map::const_iterator i = susp.begin();
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i != susp.end(); ++i)
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suspvars &= i->second;
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bdd allaccap = bddtrue; // set of atomic prop used in accepting SCCs.
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tgba* aut = res;
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{
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scc_map sm(aut);
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sm.build_map();
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// Restrict suspvars to the set of suspension labels that occur
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// in accepting SCC.
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unsigned sn = sm.scc_count();
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for (unsigned n = 0; n < sn; n++)
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if (sm.accepting(n))
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allaccap &= sm.ap_set_of(n);
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bdd ignored = bdd_exist(suspvars, allaccap);
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suspvars = bdd_existcomp(suspvars, allaccap);
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res = scc_filter(aut, false, &sm, suspvars, early_susp, ignored);
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}
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delete aut;
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// Do we need to synchronize any suspended formula?
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if (!susp.empty() && !no_susp_product)
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for (formula_bdd_map::const_iterator i = susp.begin();
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i != susp.end(); ++i)
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if ((allaccap & i->second) == allaccap)
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res = susp_prod(res, i->first, i->second);
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g->destroy();
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for (ltl_suspender_visitor::fmap_t::iterator i = g2s.begin();
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i != g2s.end(); ++i)
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i->second->destroy();
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for (ltl_suspender_visitor::fmap_t::iterator i = a2o.begin();
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i != a2o.end(); ++i)
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i->second->destroy();
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return res;
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}
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}
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