Adding tgba-based stutter-invariance checking

* src/tgbaalgos/closure.cc, src/tgbaalgos/closure.hh:
Add closure function.
* src/tgbaalgos/stutterize.cc, src/tgbaalgos/stutterize.hh:
Add two implementations of "self-loopize" function.
* src/tgbaalgos/Makefile.am: Add them.
* src/tgba/tgbasl.cc, src/tgba/tgbasl.hh: On-the-fly implementation of
self-loopize.
* src/tgba/Makefile.am: Add it.
* src/tgbatest/ltl2tgba.cc, src/tgbatest/stutter_invariant.test: Test
closure and sl.
* src/tgbatest/Makefile.am: Adjust.
* src/bin/ltlfilt.cc: Modify stutter-invariant option to use
automaton-based checking rather than syntactic-based checking.
* src/ltlvisit/remove_x.cc, src/ltlvisit/remove_x.hh:
Remove is_stutter_insensitive function.
* src/tgbaalgos/stutter_invariance.cc,
src/tgbaalgos/stutter_invariance.hh: Check if a formula is
stutter-invariant using closure and sl.
* wrap/python/spot.i: Add closure and sl bindings.
* bench/stutter/stutter_invariance_formulas.cc: Generate benchmarks from
given formulas.
* bench/stutter/stutter_invariance_randomgraph.cc: Generate benchmarks
from random automata.
* bench/stutter/Makefile.am: Add them.
* configure.ac: Add bench/stutter/Makefile.
* bench/Makefile.am: Add stutter subdirectory.
* README: Document bench/stutter directory.

src/tgbaalgos/stutterize.hh

@@ -0,0 +1,43 @@
+// -*- coding: utf-8 -*-
+// Copyright (C) 2014 Laboratoire de Recherche
+// et Développement de l'Epita (LRDE).
+// Copyright (C) 2004, 2005 Laboratoire d'Informatique de Paris 6 (LIP6),
+// département Systèmes Répartis Coopératifs (SRC), Université Pierre
+// et Marie Curie.
+//
+// This file is part of Spot, a model checking library.
+//
+// Spot is free software; you can redistribute it and/or modify it
+// under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 3 of the License, or
+// (at your option) any later version.
+//
+// Spot is distributed in the hope that it will be useful, but WITHOUT
+// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+// or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
+// License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+#ifndef SPOT_TGBAALGOS_STUTTERIZE_HH
+# define SPOT_TGBAALGOS_STUTTERIZE_HH
+
+#include "tgba/tgbagraph.hh"
+
+namespace spot
+{
+  SPOT_API tgba_digraph_ptr
+  sl(const const_tgba_digraph_ptr&, const ltl::formula*);
+
+  SPOT_API tgba_digraph_ptr
+  sl(const const_tgba_digraph_ptr&, bdd);
+
+  SPOT_API tgba_digraph_ptr
+  sl2(const const_tgba_digraph_ptr&, const ltl::formula*);
+
+  SPOT_API tgba_digraph_ptr
+  sl2(const const_tgba_digraph_ptr&, bdd);
+}
+
+#endif