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sccinfo: introduce is_rejecting()

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Because scc_info does not perform a full emptiness check, it is not
always able to tell whether an SCC is accepting if the acceptance
condition use Fin primitives.  This introduce is_rejecting_scc() in
addition to to is_accepting_scc().  Only one of them may be true, but
they can both be false if scc_info has no idea whether the SCC is
accepting.

* src/tgbaalgos/sccinfo.cc, src/tgbaalgos/sccinfo.hh: Implement
is_rejecting_scc().
* src/bin/ltlcross.cc, src/tgba/acc.cc, src/tgba/acc.hh,
src/tgbaalgos/dtgbacomp.cc, src/tgbaalgos/isweakscc.cc,
src/tgbaalgos/remfin.cc, src/tgbaalgos/safety.cc,
src/tgbaalgos/sccfilter.cc: Use it.
* src/tgbaalgos/dotty.cc: Use is_rejecting_scc() and is_accepting_scc()
to color SCCs.
* doc/org/oaut.org: Document the colors used.
* src/tgbatest/neverclaimread.test, src/tgbatest/readsave.test: Adjust
tests.
* src/tgbatest/sccdot.test: New test case.
* src/tgbatest/Makefile.am: Add it.
This commit is contained in:
Alexandre Duret-Lutz 2015-03-03 18:09:44 +01:00
parent 8658441839
commit ebe4ffc507
16 changed files with 475 additions and 45 deletions
Download patch file Download diff file Expand all files Collapse all files

28
src/tgbaalgos/sccinfo.cc
View file

@ -120,7 +120,10 @@ namespace spot
node_.emplace_back(acc, triv);
std::swap(node_.back().succ_, root_.front().node.succ_);
std::swap(node_.back().states_, root_.front().node.states_);
node_.back().accepting_ = !triv && aut->acc().accepting(acc);
node_.back().accepting_ =
!triv && root_.front().node.accepting_;
node_.back().rejecting_ =
triv || !aut->acc().inf_satisfiable(acc);
root_.pop_front();
// Record the transition between the SCC being popped
// and the previous SCC.
@ -177,7 +180,7 @@ namespace spot
// non-dead SCC has necessarily been crossed by our path to
// this state: there is a state S2 in our path which belongs
// to this SCC too. We are going to merge all states between
// this S1 and S2 into this SCC.
// this S1 and S2 into this SCC..
//
// This merge is easy to do because the order of the SCC in
// ROOT is descending: we just have to merge all SCCs from the
@ -186,17 +189,24 @@ namespace spot
int threshold = spi;
std::list<unsigned> states;
scc_succs succs;
bool is_accepting = false;
// If this is a self-loop, check its acceptance alone.
if (dest == succ->src)
is_accepting = aut->acc().accepting(acc);
assert(!root_.empty());
while (threshold > root_.front().index)
{
assert(!root_.empty());
acc |= root_.front().node.acc_;
acc |= root_.front().in_acc;
is_accepting |= root_.front().node.accepting_;
states.splice(states.end(), root_.front().node.states_);
succs.insert(succs.end(),
root_.front().node.succ_.begin(),
root_.front().node.succ_.end());
root_.pop_front();
assert(!root_.empty());
}
// Note that we do not always have
@ -207,6 +217,8 @@ namespace spot
// Accumulate all acceptance conditions, states, SCC
// successors, and conditions into the merged SCC.
root_.front().node.acc_ |= acc;
root_.front().node.accepting_ |= is_accepting
|| aut->acc().accepting(root_.front().node.acc_);
root_.front().node.states_.splice(root_.front().node.states_.end(),
states);
root_.front().node.succ_.insert(root_.front().node.succ_.end(),
@ -215,12 +227,12 @@ namespace spot
root_.front().node.trivial_ = false;
}
// An SCC is useful if it is accepting or it has a successor SCC
// that is useful.
// An SCC is useful if it is not rejecting or it has a successor
// SCC that is useful.
unsigned scccount = scc_count();
for (unsigned i = 0; i < scccount; ++i)
{
if (node_[i].is_accepting())
if (!node_[i].is_rejecting())
{
node_[i].useful_ = true;
continue;
@ -253,7 +265,7 @@ namespace spot
for (unsigned src = 0; src < n; ++src)
{
unsigned src_scc = scc_of(src);
if (src_scc == -1U || !is_accepting_scc(src_scc))
if (src_scc == -1U || is_rejecting_scc(src_scc))
continue;
auto& s = result[src_scc];
for (auto& t: aut_->out(src))
@ -272,7 +284,7 @@ namespace spot
std::vector<bool> result(scc_count());
auto acc = used_acc();
for (unsigned s = 0; s < n; ++s)
result[s] = !is_accepting_scc(s) || acc[s].size() == 1;
result[s] = is_rejecting_scc(s) || acc[s].size() == 1;
return result;
}