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powerset: deal with accepting sinks more effectively

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Part of #444.

* spot/twaalgos/powerset.cc, spot/twaalgos/powerset.hh: Implement
accepting sink handling.
* spot/twaalgos/minimize.cc (minimize_wdba): Pass sinks to
tgba_powerset.
* spot/misc/bitvect.hh: Add an interesects method.
* tests/core/ltl2tgba2.test: More tests.
* NEWS: Mention this new feature.
This commit is contained in:
Alexandre Duret-Lutz 2020-12-08 17:55:50 +01:00
parent eeaed5592f
commit 48edfd80c2
6 changed files with 75 additions and 8 deletions
Download patch file Download diff file Expand all files Collapse all files

20
spot/twaalgos/minimize.cc
View file

@ -393,7 +393,25 @@ namespace spot
}
else
{
det_a = tgba_powerset(a, aborter);
// Find any accepting sink state, to speed up the
// determinization by merging all states containing a sink
// state.
//
// We only as consider as "accepting sink" any state
// that have an accepting self-loop labeled by true.
std::vector<unsigned> acc_sinks;
unsigned ns = a->num_states();
for (unsigned n = 0; n < ns; ++n)
{
for (auto& e: a->out(n))
if (e.dst == n && e.cond == bddtrue
&& a->acc().accepting(e.acc))
{
acc_sinks.push_back(n);
break;
}
}
det_a = tgba_powerset(a, aborter, &acc_sinks);
if (!det_a)
return nullptr;
}

27
spot/twaalgos/powerset.cc
View file

@ -82,7 +82,8 @@ namespace spot
twa_graph_ptr
tgba_powerset(const const_twa_graph_ptr& aut, power_map& pm, bool merge,
const output_aborter* aborter)
const output_aborter* aborter,
std::vector<unsigned>* accepting_sinks)
{
unsigned ns = aut->num_states();
unsigned nap = aut->ap().size();
@ -207,6 +208,23 @@ namespace spot
auto res = make_twa_graph(aut->get_dict());
res->copy_ap_of(aut);
bitvect* acc_sinks = nullptr;
if (accepting_sinks)
{
acc_sinks = make_bitvect(ns);
for (unsigned s: *accepting_sinks)
acc_sinks->set(s);
toclean.emplace_back(acc_sinks);
// The accepting sink is the first registered state by
// convention.
power_state ps = bv_to_ps(acc_sinks);
unsigned num = res->new_state();
seen[acc_sinks] = num;
assert(pm.map_.size() == num);
pm.map_.emplace_back(std::move(ps));
}
{
unsigned init_num = aut->get_init_state_number();
auto bvi = make_bitvect(ns);
@ -239,6 +257,8 @@ namespace spot
auto dst = &om->at(c);
if (dst->is_fully_clear())
continue;
if (acc_sinks && dst->intersects(*acc_sinks))
*dst = *acc_sinks;
auto i = seen.find(dst);
unsigned dst_num;
if (i != seen.end())
@ -274,10 +294,11 @@ namespace spot
twa_graph_ptr
tgba_powerset(const const_twa_graph_ptr& aut,
const output_aborter* aborter)
const output_aborter* aborter,
std::vector<unsigned>* accepting_sinks)
{
power_map pm;
return tgba_powerset(aut, pm, true, aborter);
return tgba_powerset(aut, pm, true, aborter, accepting_sinks);
}

11
spot/twaalgos/powerset.hh
View file

@ -94,14 +94,21 @@ namespace spot
///
/// If ab \a aborter is given, abort the construction whenever it
/// would build an automaton that is too large, and return nullptr.
///
/// If a vector of accepting sinks is given, all power-state that
/// contains any accepting sink will be merged into a single state
/// with number 0.
///
//@{
SPOT_API twa_graph_ptr
tgba_powerset(const const_twa_graph_ptr& aut,
power_map& pm, bool merge = true,
const output_aborter* aborter = nullptr);
const output_aborter* aborter = nullptr,
std::vector<unsigned>* accepting_sinks = nullptr);
SPOT_API twa_graph_ptr
tgba_powerset(const const_twa_graph_ptr& aut,
const output_aborter* aborter = nullptr);
const output_aborter* aborter = nullptr,
std::vector<unsigned>* accepting_sinks = nullptr);
//@}