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Add an option to use WDBA only if it reduces the size of the automaton.

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* src/tgba/tgbaexplicit.hh (num_states): New method.
* src/tgbaalgos/minimize.hh, src/tgbaalgos/minimize.cc
(minimize_obligation): Add a reject_bigger option.
* src/tgbatest/ltl2tgba.cc (-RM): New option.
* src/tgbatest/spotlbtt.test: Test -RM.
* bench/ltl2tgba/algorithms: Include -RM in addition to -Rm, and
replace -RDS by -RIS.
* NEWS: Mention this.
This commit is contained in:
Alexandre Duret-Lutz 2012-08-28 10:25:02 +02:00
parent f7af4e65f6
commit 60ec3acea0
7 changed files with 77 additions and 12 deletions
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4
NEWS
View file

@ -31,6 +31,10 @@ New in spot 0.9.2a:
iterated_simulations() will alternate direct and reverse
simulations in a loop as long as it diminishes the size of the
automaton.
* minimize_obligation() has a new option to disable WDBA
minimization it cases it would produce a deterministic automaton
that is bigger than the original TGBA. So this effectively
gives the choice between less states or more determinism.
New in spot 0.9.2 (2012-07-02):

26
bench/ltl2tgba/algorithms
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@ -98,7 +98,7 @@ Algorithm
{
Name = "Spot FM Sim (degen)"
Path = "$LBTT_TRANSLATE"
Parameters = "--spin '$LTL2TGBA -f -N -R3 -r7 -x -RDS -F'"
Parameters = "--spin '$LTL2TGBA -f -N -R3 -r7 -x -RIS -F'"
Enabled = yes
}
@ -114,7 +114,7 @@ Algorithm
{
Name = "Spot FM WDBA+Sim (degen)"
Path = "$LBTT_TRANSLATE"
Parameters = "--spin '$LTL2TGBA -f -N -R3 -r7 -x -Rm -RDS -F'"
Parameters = "--spin '$LTL2TGBA -f -N -R3 -r7 -x -Rm -RIS -F'"
Enabled = yes
}
@ -138,7 +138,7 @@ Algorithm
{
Name = "Spot FM Sim (TGBA)"
Path = "$LBTT_TRANSLATE"
Parameters = "--spot '$LTL2TGBA -f -t -R3 -r7 -x -RDS -F'"
Parameters = "--spot '$LTL2TGBA -f -t -R3 -r7 -x -RIS -F'"
Enabled = yes
}
@ -152,9 +152,25 @@ Algorithm
Algorithm
{
Name = "Spot FM WDBA+Sim (TGBA)"
Name = "Spot FM WDBA* (TGBA)"
Path = "$LBTT_TRANSLATE"
Parameters = "--spot '$LTL2TGBA -f -t -R3 -r7 -x -Rm -RDS -F'"
Parameters = "--spot '$LTL2TGBA -f -t -R3f -r7 -x -RM -F'"
Enabled = yes
}
Algorithm
{
Name = "Spot FM WDBA+ISim (TGBA)"
Path = "$LBTT_TRANSLATE"
Parameters = "--spot '$LTL2TGBA -f -t -R3 -r7 -x -Rm -RIS -F'"
Enabled = yes
}
Algorithm
{
Name = "Spot FM WDBA*+ISim (TGBA)"
Path = "$LBTT_TRANSLATE"
Parameters = "--spot '$LTL2TGBA -f -t -R3 -r7 -x -RM -RIS -F'"
Enabled = yes
}
EOF

7
src/tgba/tgbaexplicit.hh
View file

@ -283,6 +283,12 @@ namespace spot
return add_state(State::default_val);
}
size_t num_states() const
{
// Do not use ls_.size() because it may contain aliases.
return sl_.size();
}
transition*
create_transition(State* source, const State* dest)
{
@ -508,7 +514,6 @@ namespace spot
return to_string_func_(i->second);
}
/// old implementation in tgba_explicit_string
/// Create an alias for a state. Any reference to \a alias_name
/// will act as a reference to \a real_name.
void add_state_alias(const label_t& alias, const label_t& real)

15
src/tgbaalgos/minimize.cc
View file

@ -47,6 +47,7 @@
#include "tgbaalgos/scc.hh"
#include "tgbaalgos/ltl2tgba_fm.hh"
#include "tgbaalgos/bfssteps.hh"
#include "tgbaalgos/stats.hh"
namespace spot
{
@ -621,10 +622,22 @@ namespace spot
tgba*
minimize_obligation(const tgba* aut_f,
const ltl::formula* f, const tgba* aut_neg_f)
const ltl::formula* f, const tgba* aut_neg_f,
bool reject_bigger)
{
tgba_explicit_number* min_aut_f = minimize_wdba(aut_f);
if (reject_bigger)
{
// Abort if min_aut_f has more states than aut_f.
tgba_statistics orig_size = stats_reachable(aut_f);
if (orig_size.states < min_aut_f->num_states())
{
delete min_aut_f;
return const_cast<tgba*>(aut_f);
}
}
// if f is a syntactic obligation formula, the WDBA minimization
// must be correct.
if (f && f->is_syntactic_obligation())

18
src/tgbaalgos/minimize.hh
View file

@ -63,9 +63,11 @@ namespace spot
/// \brief Minimize a Büchi automaton in the WDBA class.
///
/// This takes a TGBA whose language is representable by
/// a Weak Deterministic Büchi Automaton, and construct
/// a minimal WDBA for this language.
/// This takes a TGBA whose language is representable by a Weak
/// Deterministic Büchi Automaton, and construct a minimal WDBA for
/// this language. This essentially chains three algorithms:
/// determinization, acceptance adjustment (Löding's coloring
/// algorithm), and minimization (using a Moore-like approache).
///
/// If the input automaton does not represent a WDBA language,
/// the resulting automaton is still a WDBA, but it will not
@ -141,9 +143,17 @@ namespace spot
/// product(aut_neg_f,minize(aut))</code> are both empty. If they
/// are, the the minimization was sound. (See the paper for full
/// details.)
///
/// If \a reject_bigger is set, this function will return the input
/// automaton \a aut_f when the minimized WDBA has more states than
/// the input automaton. (More states are possible because of
/// determinization step during minimize_wdba().) Note that
/// checking the size of the minimized WDBA occurs before ensuring
/// that the minimized WDBA is correct.
tgba* minimize_obligation(const tgba* aut_f,
const ltl::formula* f = 0,
const tgba* aut_neg_f = 0);
const tgba* aut_neg_f = 0,
bool reject_bigger = false);
/// @}
}

11
src/tgbatest/ltl2tgba.cc
View file

@ -210,6 +210,9 @@ syntax(char* prog)
<< std::endl
<< " -Rm attempt to WDBA-minimize the automaton" << std::endl
<< std::endl
<< " -RM attempt to WDBA-minimize the automaton unless the "
<< "result is bigger" << std::endl
<< std::endl
<< "Automaton conversion:" << std::endl
<< " -M convert into a deterministic minimal monitor "
@ -341,6 +344,7 @@ main(int argc, char** argv)
bool graph_run_tgba_opt = false;
bool opt_reduce = false;
bool opt_minimize = false;
bool reject_bigger = false;
bool opt_bisim_ta = false;
bool opt_monitor = false;
bool containment = false;
@ -682,6 +686,11 @@ main(int argc, char** argv)
{
opt_minimize = true;
}
else if (!strcmp(argv[formula_index], "-RM"))
{
opt_minimize = true;
reject_bigger = true;
}
else if (!strcmp(argv[formula_index], "-RT"))
{
opt_bisim_ta = true;
@ -1025,7 +1034,7 @@ main(int argc, char** argv)
if (opt_minimize)
{
tm.start("obligation minimization");
minimized = minimize_obligation(a, f);
minimized = minimize_obligation(a, f, 0, reject_bigger);
tm.stop("obligation minimization");
if (minimized == 0)

8
src/tgbatest/spotlbtt.test
View file

@ -167,6 +167,14 @@ Algorithm
Enabled = yes
}
Algorithm
{
Name = "Spot (Couvreur -- FM), +pre +WDBA(rejbig)"
Path = "${LBTT_TRANSLATE}"
Parameters = "--spot '../ltl2tgba -r4 -R3 -RM -F -f -t'"
Enabled = yes
}
Algorithm
{
Name = "Spot (Couvreur -- LaCIM), +pre +WDBA"