Commit 15c6fd95 authored by Alexandre Duret-Lutz's avatar Alexandre Duret-Lutz

alternation: fix detection of non-weak automata

Fixes #218.

* spot/twaalgos/alternation.cc: Adjust check.
* tests/core/alternating.test: Add test case from #218.
* NEWS: Mention the bug.
parent 60bc269f
......@@ -27,6 +27,9 @@ New in spot 2.3.0.dev (not yet released)
spot::acc_word::op and spot::acc_word::type had to be renamed as
spot::acc_word::sub.op and spot::acc_word::sub.type.
- alternation_removal() was not always reporting the unsupported
non-weak automata.
New in spot 2.3 (2017-01-19)
Build:
......
......@@ -104,33 +104,34 @@ namespace spot
unsigned reject_1_count_ = 0;
std::set<unsigned> true_states_;
bool ensure_weak_state(unsigned src, unsigned scc)
bool ensure_weak_scc(unsigned scc)
{
bool first = true;
bool reject_cycle = false;
acc_cond::mark_t m = 0U;
for (auto& t: aut_->out(src))
for (unsigned d: aut_->univ_dests(t.dst))
if (si_.scc_of(d) == scc)
{
if (first)
{
first = false;
m = t.acc;
reject_cycle = !aut_->acc().accepting(m);
}
else if (m != t.acc)
{
throw std::runtime_error
("alternation_removal() only work with weak "
"alternating automata");
}
// In case of a universal edge we only
// need to check the first destination
// inside the SCC, because the other
// have the same t.acc.
break;
}
for (unsigned src: si_.states_of(scc))
for (auto& t: aut_->out(src))
for (unsigned d: aut_->univ_dests(t.dst))
if (si_.scc_of(d) == scc)
{
if (first)
{
first = false;
m = t.acc;
reject_cycle = !aut_->acc().accepting(m);
}
else if (m != t.acc)
{
throw std::runtime_error
("alternation_removal() only work with weak "
"alternating automata");
}
// In case of a universal edge we only
// need to check the first destination
// inside the SCC, because the other
// have the same t.acc.
break;
}
return reject_cycle;
}
......@@ -155,10 +156,11 @@ namespace spot
// decide rejecting/accepting.
assert(si_.is_accepting_scc(n));
unsigned s = si_.states_of(n).front();
bool rej = ensure_weak_state(s, n);
// Catch unsupported types of automata
bool rej = ensure_weak_scc(n);
assert(rej == false);
// Detect if it is a "true state"
unsigned s = si_.states_of(n).front();
auto& ss = g.state_storage(s);
if (ss.succ == ss.succ_tail)
{
......@@ -168,14 +170,10 @@ namespace spot
}
}
}
else
else if (ensure_weak_scc(n))
{
for (auto src: si_.states_of(n))
if (ensure_weak_state(src, n))
{
class_of_[n] = reject_more;
has_reject_more_ = true;
}
class_of_[n] = reject_more;
has_reject_more_ = true;
}
}
}
......
......@@ -374,5 +374,25 @@ State: 2 "t"
[t] 2
--END--
EOF
autfilt --tgba in >out 2>&1 && exit 1
autfilt --tgba in 2>out && exit 1
grep 'autfilt.*weak.*alternating' out
cat >in <<EOF
HOA: v1
States: 4
AP: 2 "a" "b"
Start: 0&1
Acceptance: 1 Inf(0)
--BODY--
State: 0 {0}
[0] 2
State: 2 /*{0}*/
[0] 0
State: 1 {0}
[1] 3
State: 3 /*{0}*/
[1] 1
--END--
EOF
autfilt --tgba in 2>out && exit 1
grep 'autfilt.*weak.*alternating' out
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