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twa: introduce exclusive_word() and exclusive_run()

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* spot/twa/twa.cc, spot/twa/twa.hh: Add these methods.
* NEWS, tests/python/contains.ipynb: Document them.
This commit is contained in:
Alexandre Duret-Lutz 2018-06-29 20:50:19 +02:00
parent 3c12015181
commit 4e8b35d7ca
4 changed files with 298 additions and 3 deletions
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56
spot/twa/twa.cc
View file

@ -28,6 +28,9 @@
#include <spot/twaalgos/remfin.hh>
#include <spot/twaalgos/alternation.hh>
#include <spot/twa/twaproduct.hh>
#include <spot/twaalgos/dualize.hh>
#include <spot/twaalgos/postproc.hh>
#include <spot/twaalgos/isdet.hh>
#include <utility>
namespace spot
@ -117,7 +120,7 @@ namespace spot
twa::intersecting_run(const_twa_ptr other, bool from_other) const
{
auto a = shared_from_this();
if (from_other)
if (!from_other)
other = remove_fin_maybe(other);
else
a = remove_fin_maybe(a);
@ -135,6 +138,57 @@ namespace spot
return otf_product(a1, a2)->accepting_word();
}
namespace
{
static const_twa_graph_ptr
ensure_deterministic(const const_twa_ptr& aut_in)
{
const_twa_graph_ptr aut =
std::dynamic_pointer_cast<const twa_graph>(aut_in);
if (!aut)
aut = make_twa_graph(aut_in, twa::prop_set::all());
if (is_deterministic(aut))
return aut;
postprocessor p;
p.set_type(postprocessor::Generic);
p.set_pref(postprocessor::Deterministic);
p.set_level(postprocessor::Low);
return p.run(std::const_pointer_cast<twa_graph>(aut));
}
}
twa_run_ptr
twa::exclusive_run(const_twa_ptr other) const
{
const_twa_ptr a = shared_from_this();
const_twa_ptr b = other;
// We have to find a run in A\B or in B\A. When possible, let's
// make sure the first automaton we complement is deterministic.
if (auto aa = std::dynamic_pointer_cast<const twa_graph>(a))
if (is_deterministic(aa))
std::swap(a, b);
if (auto run = a->intersecting_run(dualize(ensure_deterministic(b))))
return run;
return b->intersecting_run(dualize(ensure_deterministic(a)));
}
twa_word_ptr
twa::exclusive_word(const_twa_ptr other) const
{
const_twa_ptr a = shared_from_this();
const_twa_ptr b = other;
// We have to find a word in A\B or in B\A. When possible, let's
// make sure the first automaton we complement is deterministic.
if (auto aa = std::dynamic_pointer_cast<const twa_graph>(a))
if (is_deterministic(aa))
std::swap(a, b);
if (auto word = a->intersecting_word(dualize(ensure_deterministic(b))))
return word;
return b->intersecting_word(dualize(ensure_deterministic(a)));
}
void
twa::set_named_prop(std::string s, std::nullptr_t)
{

24
spot/twa/twa.hh
View file

@ -888,6 +888,30 @@ namespace spot
/// Return nullptr if no accepting word were found.
virtual twa_word_ptr intersecting_word(const_twa_ptr other) const;
/// \brief Return an accepting run recognizing a word accepted by
/// exactly one of the two automata.
///
/// If \a from_other is true, the returned run will be over the
/// \a other automaton. Otherwise, the run will be over this
/// automaton.
///
/// Note that this method currently only works if the automaton
/// from which the accepting run is extracted uses Fin-less acceptance.
/// (The other automaton can have any acceptance condition.)
///
/// Return nullptr iff the two automata recognize the same
/// language.
virtual twa_run_ptr exclusive_run(const_twa_ptr other) const;
/// \brief Return a word accepted by exactly one of the two
/// automata.
///
/// Note that this method DOES works with Fin acceptance.
///
/// Return nullptr iff the two automata recognize the same
/// language.
virtual twa_word_ptr exclusive_word(const_twa_ptr other) const;
private:
acc_cond acc_;