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streett_to_generalized_buchi: fix incorrect algorithm

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Fixes #284, reported by Juraj Major.

* spot/twaalgos/totgba.cc: Fix the algorithm.
* spot/twa/acc.hh: More doc for future generations.
* tests/core/scc.test: More test cases.
* NEWS: Mention the issues.
This commit is contained in:
Alexandre Duret-Lutz 2017-09-26 17:17:17 +02:00
parent 210046e8cd
commit f81fb31136
4 changed files with 88 additions and 13 deletions
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24
spot/twaalgos/totgba.cc
View file

@ -533,7 +533,9 @@ namespace spot
acc_cond::mark_t fin;
std::tie(inf, fin) = in->get_acceptance().used_inf_fin_sets();
unsigned p = inf.count();
acc_cond::mark_t fin_not_inf = fin - inf;
// At some point we will remove anything that is not used as Inf.
acc_cond::mark_t to_strip = in->acc().all_sets() - inf;
acc_cond::mark_t inf_alone = 0U;
if (!p)
return remove_fin(in);
@ -543,8 +545,11 @@ namespace spot
std::vector<acc_cond::mark_t> inf_to_finpairs(numsets, 0U);
for (auto pair: pairs)
{
for (unsigned mark: pair.fin.sets())
fin_to_infpairs[mark] |= pair.inf;
if (pair.fin)
for (unsigned mark: pair.fin.sets())
fin_to_infpairs[mark] |= pair.inf;
else
inf_alone |= pair.inf;
for (unsigned mark: pair.inf.sets())
inf_to_finpairs[mark] |= pair.fin;
@ -634,11 +639,14 @@ namespace spot
for (unsigned mark: (t.acc & fin).sets())
pend |= fin_to_infpairs[mark];
// If we see some Inf set immediately, they are not
// pending anymore.
pend -= t.acc & inf;
// Label this transition with all non-pending
// inf sets. The strip will shift everything
// to the correct numbers in the targets.
acc = (inf - pend).strip(fin - inf);
acc = (inf - pend).strip(to_strip);
// Adjust the pending sets to what will be necessary
// required on the destination state.
if (sbacc)
@ -651,14 +659,14 @@ namespace spot
pend -= a & inf;
}
pend |= scc_inf_wo_fin;
pend |= inf_alone;
}
else if (no_fin && maybe_acc)
{
// If the acceptance is (Fin(0) | Inf(1)) & Inf(2)
// but we do not see any Fin set in this SCC, an
// but we do not see any Fin set in this SCC, a
// mark {2} should become {1,2} before striping.
acc = (t.acc | (inf - scc_inf_wo_fin)).strip(fin_not_inf);
acc = (t.acc | (inf - scc_inf_wo_fin)).strip(to_strip);
}
assert((acc & out->acc().all_sets()) == acc);
@ -694,7 +702,7 @@ namespace spot
stpend -= a & inf;
}
st2gba_state d(t.dst, stpend | scc_inf_wo_fin);
st2gba_state d(t.dst, stpend | inf_alone);
// Have we already seen this destination?
unsigned dest;
auto dres = bs2num.emplace(d, 0);