alarsyo/spot
1
0
Fork 0
Code Issues Pull requests Projects Releases Wiki Activity

complete: get rid of tgba_explicit_number

Browse source 
* src/tgbaalgos/complete.cc, src/tgbaalgos/complete.hh
(tgba_complete_here): New method for tgba_digraph.
(tgba_complete): Rewrite using dupexp and the above.
This commit is contained in:
Alexandre Duret-Lutz 2014-08-10 15:18:17 +02:00
parent df05162780
commit 74e20a6ec4
2 changed files with 89 additions and 94 deletions
Download patch file Download diff file Expand all files Collapse all files

163
src/tgbaalgos/complete.cc
View file

@ -18,111 +18,96 @@
// along with this program. If not, see <http://www.gnu.org/licenses/>.
#include "complete.hh"
#include "reachiter.hh"
#include "ltlast/constant.hh"
#include "dupexp.hh"
namespace spot
{
namespace
unsigned tgba_complete_here(tgba_digraph* aut)
{
class tgbacomplete_iter:
public tgba_reachable_iterator_depth_first_stack
{
bdd_dict* dict_;
tgba_explicit_number* out_;
bdd addacc_;
typedef state_explicit_number::transition trans;
public:
tgbacomplete_iter(const tgba* a)
: tgba_reachable_iterator_depth_first_stack(a),
dict_(a->get_dict()),
out_(new tgba_explicit_number(dict_)),
addacc_(bddfalse)
unsigned n = aut->num_states();
unsigned sink = -1U;
bdd allacc = aut->all_acceptance_conditions();
if (allacc == bddfalse)
{
dict_->register_all_variables_of(a, out_);
if (a->number_of_acceptance_conditions() == 0)
// We cannot safely complete an automaton if it has no
// acceptance set as the added sink would become accepting.
// In this case, add an acceptance set to all transitions.
const ltl::formula* t = ltl::constant::true_instance();
int v = aut->get_dict()->register_acceptance_variable(t, aut);
allacc = bdd_ithvar(v);
aut->set_acceptance_conditions(allacc);
for (auto& t: aut->transitions())
t.acc = allacc;
}
else
{
// If some acceptance sets were used, loop over the states and
// seek a state that has only self loops, and that is not
// accepting. This will be our sink state.
for (unsigned i = 0; i < n; ++i)
{
const ltl::formula* t = ltl::constant::true_instance();
int accvar =
dict_->register_acceptance_variable(t, out_);
addacc_ = bdd_ithvar(accvar);
out_->set_acceptance_conditions(addacc_);
}
else
{
out_->set_acceptance_conditions(a->all_acceptance_conditions());
bool selfloop = true;
bdd accsum = bddfalse;
for (auto& t: aut->out(i))
{
if (t.dst != i) // Not a self-loop
{
selfloop = false;
break;
}
accsum |= t.acc;
}
if (selfloop && accsum != allacc) // We have found a sink!
{
sink = i;
break;
}
}
}
tgba_explicit_number*
result()
// If we haven't found any sink, simply add one.
if (sink == -1U)
{
return out_;
sink = aut->new_state();
++n;
}
void
end()
// Now complete all states (including the sink).
for (unsigned i = 0; i < n; ++i)
{
out_->merge_transitions();
// create a sink state if needed.
if (out_->has_state(0))
{
trans* t = out_->create_transition(0, 0);
t->condition = bddtrue;
}
}
void process_state(const state*, int n,
tgba_succ_iterator* i)
{
// add a transition to a sink state if the state is not complete.
bdd all = bddtrue;
bdd missingcond = bddtrue;
bdd acc = bddfalse;
if (i->first())
for (auto& t: aut->out(i))
{
// In case the automaton use state-based acceptance, propagate
// the acceptance of the first transition to the one we add.
acc = i->current_acceptance_conditions();
do
all -= i->current_condition();
while (i->next());
}
if (all != bddfalse)
{
trans* t = out_->create_transition(n, 0);
t->condition = all;
t->acceptance_conditions = acc | addacc_;
missingcond -= t.cond;
// FIXME: This is ugly.
//
// In case the automaton uses state-based acceptance, we
// need to put the new transition in the same set as all
// the other.
//
// In case the automaton uses transition-based acceptance,
// it does not matter what acceptance set we put the new
// transition into.
//
// So in both cases, we put the transition in the same
// acceptance sets as the last outgoing transition of the
// state.
acc = t.acc;
}
// In case the automaton use state-based acceptance, propagate
// the acceptance of the first transition to the one we add.
if (missingcond != bddfalse)
aut->new_transition(i, sink, missingcond, acc);
}
void
process_link(const state*, int in,
const state*, int out,
const tgba_succ_iterator* si)
{
assert(in > 0);
assert(out > 0);
trans* t1 = out_->create_transition(in, out);
t1->condition = si->current_condition();
t1->acceptance_conditions =
si->current_acceptance_conditions() | addacc_;
}
};
} // anonymous
tgba_explicit_number* tgba_complete(const tgba* aut)
{
tgbacomplete_iter ci(aut);
ci.run();
return ci.result();
return sink;
}
tgba_digraph* tgba_complete(const tgba* aut)
{
tgba_digraph* res = tgba_dupexp_dfs(aut);
tgba_complete_here(res);
return res;
}
}

20
src/tgbaalgos/complete.hh
View file

@ -1,5 +1,5 @@
// -*- coding: utf-8 -*-
// Copyright (C) 2013 Laboratoire de Recherche et Développement
// Copyright (C) 2013, 2014 Laboratoire de Recherche et Développement
// de l'Epita.
//
// This file is part of Spot, a model checking library.
@ -20,13 +20,23 @@
#ifndef SPOT_TGBAALGOS_COMPLETE_HH
# define SPOT_TGBAALGOS_COMPLETE_HH
#include "tgba/tgbaexplicit.hh"
#include "tgba/tgbagraph.hh"
namespace spot
{
/// Complete a TGBA
SPOT_API tgba_explicit_number*
tgba_complete(const tgba* aut);
/// \brief Complete a tgba_digraph in place.
///
/// If the tgba has no acceptance set, one will be added. The
/// returned value is the number of the sink state (it can be a new
/// state added for completion, or an existing non-accepting state
/// that has been reused as sink state because it had not outgoing
/// transitions apart from self-loops.)
SPOT_API unsigned tgba_complete_here(tgba_digraph* aut);
/// \brief Clone a tgba and complete it.
///
/// If the tgba has no acceptance set, one will be added.
SPOT_API tgba_digraph* tgba_complete(const tgba* aut);
}
#endif // SPOT_TGBAALGOS_COMPLETE_HH