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dbacomp: connect only back-links and generalize to tgba

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* src/tgbaalgos/dbacomp.cc: Here.
* src/tgbaalgos/dbacomp.hh: Adjust documentation.
* src/tgbatest/dbacomp.test: New file.
* src/tgbatest/Makefile.am (TESTS): Add it.
* src/tgbatest/det.test: Update.
This commit is contained in:
Alexandre Duret-Lutz 2013-02-03 00:16:32 +01:00
parent 63b7cdb6c8
commit 78e76eb07d
5 changed files with 140 additions and 35 deletions
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93
src/tgbaalgos/dbacomp.cc
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@ -26,37 +26,32 @@ namespace spot
namespace
{
class dbacomp_iter: public tgba_reachable_iterator_depth_first
class dbacomp_iter: public tgba_reachable_iterator_depth_first_stack
{
bdd orig_acc_;
bdd all_neg_;
bdd acc_;
bdd_dict* dict_;
tgba_explicit_number* out_;
int num_acc_;
typedef state_explicit_number::transition trans;
public:
dbacomp_iter(const tgba* a)
: tgba_reachable_iterator_depth_first(a),
: tgba_reachable_iterator_depth_first_stack(a),
dict_(a->get_dict()),
out_(new tgba_explicit_number(dict_))
{
dict_->register_all_variables_of(a, out_);
unsigned c = a->number_of_acceptance_conditions();
orig_acc_ = a->all_acceptance_conditions();
if (c == 1)
{
out_->copy_acceptance_conditions_of(a);
acc_ = orig_acc_;
}
else
{
// If there is no acceptance conditions in the original
// automaton, add one.
assert(c == 0);
int accvar = dict_->register_acceptance_variable
(ltl::constant::true_instance(), out_);
acc_ = bdd_ithvar(accvar);
out_->set_acceptance_conditions(acc_);
}
all_neg_ = a->neg_acceptance_conditions();
num_acc_ = a->number_of_acceptance_conditions();
// Register one acceptance condition for the result.
int accvar = dict_->register_acceptance_variable
(ltl::constant::true_instance(), out_);
acc_ = bdd_ithvar(accvar);
out_->set_acceptance_conditions(acc_);
}
tgba_explicit_number*
@ -106,19 +101,61 @@ namespace spot
trans* t1 = out_->create_transition(in, out);
t1->condition = si->current_condition();
// Negative states encode a copy of the automaton in which all
// accepting transitions have been removed, and all the
// remaining transitions are now accepting.
// Negative states encode NUM_ACC_ copies of the automaton.
// In each copy transitions labeled by one of the acceptance
// set have been removed, and all the remaining transitions
// are now accepting.
// For each state S, we have NUM_ACC_ additional copies
// labeled S*-NUM_ACC, S*-NUM_ACC+1, ... S*-NUM_ACC+(NUM_ACC-1),
if (a != orig_acc_)
{
trans* t2 = out_->create_transition(-in, -out);
t2->condition = si->current_condition();
t2->acceptance_conditions = acc_;
}
bool backlink = on_stack(out);
int add = 0;
if (a == bddfalse)
a = all_neg_;
// Iterate over all the acceptance conditions in 'a'.
bdd ac = a;
while (ac != bddtrue)
{
bdd h = bdd_high(ac);
if (h == bddfalse)
{
trans* t2 = out_->create_transition(in * -num_acc_ + add,
out * -num_acc_ + add);
t2->condition = si->current_condition();
t2->acceptance_conditions = acc_;
// A non-deterministic transition between the two copies.
trans* t3 = out_->create_transition(in, -out);
t3->condition = si->current_condition();
if (backlink)
{
// Since we are closing a cycle, add
// a non-deterministic transition from
// the original automaton to this copy.
trans* t3 =
out_->create_transition(in, out * -num_acc_ + add);
t3->condition = si->current_condition();
}
ac = bdd_low(ac);
}
else
{
// We know that only one variable can be positive
// on any branch, so since we have just seen such
// a variable, we want to go to explore its LOW
// branch for more positive variables. The only
// case where we will not do that is if the LOW
// branch is false. In that case we take the HIGH
// branch to enumerate all the remaining negated
// variables.
bdd tmp = bdd_low(ac);
if (tmp != bddfalse)
ac = tmp;
else
ac = h;
}
++add;
}
assert(add == num_acc_);
}
}
};