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specialize scc_filter for inherently_weak automata

Browse source 
Part of issue #351.

* spot/twaalgos/sccfilter.cc, spot/twaalgos/sccfilter.hh: Specialize
for inherently-weak automata.
* spot/twaalgos/postproc.cc: Simplify.
* tests/core/dca2.test, tests/core/parity2.test,
tests/core/prodor.test, tests/core/randomize.test,
tests/python/automata.ipynb, tests/python/highlighting.ipynb,
tests/python/product.ipynb, tests/python/remfin.py,
tests/python/stutter-inv.ipynb: Adjust.
* NEWS: Mention it.
This commit is contained in:
Alexandre Duret-Lutz 2018-06-11 15:01:49 +02:00
parent 2fad1ff6de
commit 95d732e331
13 changed files with 1245 additions and 2011 deletions
Download patch file Download diff file Expand all files Collapse all files

71
spot/twaalgos/sccfilter.cc
View file

@ -124,6 +124,53 @@ namespace spot
}
};
// Transform inherently weak automata into weak Büchi automata.
template <bool buchi, class next_filter = id_filter>
struct weak_filter: next_filter
{
acc_cond::mark_t acc_m = {0};
acc_cond::mark_t rej_m = {};
template<typename... Args>
weak_filter(scc_info* si, Args&&... args)
: next_filter(si, std::forward<Args>(args)...)
{
if (!buchi)
{
acc_m = {};
if (si->get_aut()->acc().is_co_buchi())
rej_m = {0};
}
}
filtered_trans trans(unsigned src, unsigned dst,
bdd cond, acc_cond::mark_t acc)
{
bool keep;
std::tie(keep, cond, acc) =
this->next_filter::trans(src, dst, cond, acc);
if (keep)
{
unsigned ss = this->si->scc_of(src);
if (this->si->is_accepting_scc(ss))
acc = acc_m;
else
acc = rej_m;
}
return filtered_trans(keep, cond, acc);
}
void fix_acceptance(const twa_graph_ptr& out)
{
if (buchi)
out->set_buchi();
else
out->copy_acceptance_of(this->si->get_aut());
}
};
// Remove acceptance conditions from all edges outside of
// non-accepting SCCs. If "RemoveAll" is false, keep those on
// transitions entering accepting SCCs. If "PreserveSBA", is set
@ -160,7 +207,7 @@ namespace spot
unsigned v = this->si->scc_of(dst);
// The basic rules are as follows:
//
// - If an edge is between two SCCs, is OK to remove
// - If an edge is between two SCCs, it is OK to remove
// all acceptance sets, as this edge cannot be part
// of any loop.
// - If an edge is in an non-accepting SCC, we can only
@ -370,6 +417,10 @@ namespace spot
scc_info* given_si)
{
twa_graph_ptr res;
// For weak automata, scc_filter() is already doing the right
// thing and preserves state-based acceptance.
if (aut->prop_inherently_weak())
return scc_filter(aut, remove_all_useless, given_si);
if (remove_all_useless)
res = scc_filter_apply<state_filter
<acc_filter_mask<true, true>>>(aut, given_si);
@ -385,9 +436,18 @@ namespace spot
scc_info* given_si)
{
twa_graph_ptr res;
// acc_filter_simplify only works for generalized Büchi
if (aut->acc().is_generalized_buchi())
if (aut->prop_inherently_weak())
{
if (aut->acc().is_t() || aut->acc().is_co_buchi())
res =
scc_filter_apply<state_filter<weak_filter<false>>>(aut, given_si);
else
res =
scc_filter_apply<state_filter<weak_filter<true>>>(aut, given_si);
}
else if (aut->acc().is_generalized_buchi())
{
// acc_filter_simplify only works for generalized Büchi
if (remove_all_useless)
res =
scc_filter_apply<state_filter
@ -421,6 +481,11 @@ namespace spot
false,
true,
});
if (aut->prop_inherently_weak())
{
res->prop_weak(true);
res->prop_state_acc(true);
}
return res;
}