word: introduce use_all_aps()

This allows fixing issue #388 reported by Victor Khomenko.

* spot/twaalgos/word.cc, spot/twaalgos/word.hh (use_all_aps): New
method.
* tests/python/stutter-inv.ipynb: Use it.
* tests/python/stutter.py: New file, with Victor's test case.
* tests/Makefile.am: Add python/stutter.py.

spot/twaalgos/word.cc

 // -*- coding: utf-8 -*-
-// Copyright (C) 2013-2018 Laboratoire de Recherche et Développement
+// Copyright (C) 2013-2019 Laboratoire de Recherche et Développement
 // de l'Epita (LRDE).
 //
 // This file is part of Spot, a model checking library.
@@ -44,6 +44,17 @@ namespace spot
   {
   }
 
+  void
+  twa_word::use_all_aps(bdd aps, bool positive)
+  {
+    bdd def = positive ?
+      static_cast<bdd>(bddtrue) : static_cast<bdd>(bddfalse);
+    for (bdd& i: prefix)
+      i = bdd_satoneset(i, aps, def);
+    for (bdd& i: cycle)
+      i = bdd_satoneset(i, aps, def);
+  }
+
   void
   twa_word::simplify()
   {

spot/twaalgos/word.hh

 // -*- coding: utf-8 -*-
-// Copyright (C) 2013, 2014, 2015, 2016, 2018 Laboratoire de Recherche et
+// Copyright (C) 2013, 2014, 2015, 2016, 2018, 2019 Laboratoire de Recherche et
 // Développement de l'Epita (LRDE).
 //
 // This file is part of Spot, a model checking library.
@@ -62,6 +62,13 @@ namespace spot
     /// single operand.
     void simplify();
 
+    /// \brief Use all atomic proposition.
+    ///
+    /// Make sure each letters actually use all variables in \a aps.
+    /// By default, missing variables are introduced as negative,
+    /// but setting \a positive to true will reverse that.
+    void use_all_aps(bdd aps, bool positive = false);
+
     typedef std::list<bdd> seq_t;
     seq_t prefix;
     seq_t cycle;

tests/Makefile.am

@@ -410,6 +410,7 @@ TESTS_python = \
   python/split.py \
   python/streett_totgba.py \
   python/streett_totgba2.py \
+  python/stutter.py \
   python/rs_like.py \
   python/sum.py \
   python/toparity.py \

tests/python/stutter-inv.ipynb

@@ -302,7 +302,7 @@
        "</svg>\n"
       ],
       "text/plain": [
-       "<spot.twa_graph; proxy of <Swig Object of type 'std::shared_ptr< spot::twa_graph > *' at 0x7f0a9c1ee180> >"
+       "<spot.twa_graph; proxy of <Swig Object of type 'std::shared_ptr< spot::twa_graph > *' at 0x7fbbb85b6780> >"
       ]
      },
      "metadata": {},
@@ -361,6 +361,7 @@
     "        print(f, \"is stutter invariant\")\n",
     "        return\n",
     "    word.simplify()\n",
+    "    word.use_all_aps(pos.ap_vars())\n",
     "    waut = word.as_automaton()\n",
     "    if waut.intersects(pos):\n",
     "        acc, rej, aut = \"accepted\", \"rejected\", neg\n",
@@ -602,7 +603,7 @@
        "</svg>\n"
       ],
       "text/plain": [
-       "<spot.twa_graph; proxy of <Swig Object of type 'std::shared_ptr< spot::twa_graph > *' at 0x7f0a9c250300> >"
+       "<spot.twa_graph; proxy of <Swig Object of type 'std::shared_ptr< spot::twa_graph > *' at 0x7fbbb8570cf0> >"
       ]
      },
      "metadata": {},
@@ -811,7 +812,7 @@
        "</svg>\n"
       ],
       "text/plain": [
-       "<spot.twa_graph; proxy of <Swig Object of type 'std::shared_ptr< spot::twa_graph > *' at 0x7f0a9c250300> >"
+       "<spot.twa_graph; proxy of <Swig Object of type 'std::shared_ptr< spot::twa_graph > *' at 0x7fbbb8570cf0> >"
       ]
      },
      "metadata": {},
@@ -963,7 +964,7 @@
        "</svg>\n"
       ],
       "text/plain": [
-       "<spot.twa_graph; proxy of <Swig Object of type 'std::shared_ptr< spot::twa_graph > *' at 0x7f0a9c1e1f60> >"
+       "<spot.twa_graph; proxy of <Swig Object of type 'std::shared_ptr< spot::twa_graph > *' at 0x7fbbb85b6750> >"
       ]
      },
      "metadata": {},
@@ -1061,7 +1062,7 @@
        "</svg>\n"
       ],
       "text/plain": [
-       "<spot.twa_graph; proxy of <Swig Object of type 'std::shared_ptr< spot::twa_graph > *' at 0x7f0a9c1e1840> >"
+       "<spot.twa_graph; proxy of <Swig Object of type 'std::shared_ptr< spot::twa_graph > *' at 0x7fbbb8570450> >"
       ]
      },
      "metadata": {},
@@ -1271,7 +1272,7 @@
        "</svg>\n"
       ],
       "text/plain": [
-       "<spot.twa_graph; proxy of <Swig Object of type 'std::shared_ptr< spot::twa_graph > *' at 0x7f0a9c1ee990> >"
+       "<spot.twa_graph; proxy of <Swig Object of type 'std::shared_ptr< spot::twa_graph > *' at 0x7fbbb857f120> >"
       ]
      },
      "metadata": {},
@@ -1400,7 +1401,7 @@
        "</svg>\n"
       ],
       "text/plain": [
-       "<spot.twa_graph; proxy of <Swig Object of type 'std::shared_ptr< spot::twa_graph > *' at 0x7f0a9c2502a0> >"
+       "<spot.twa_graph; proxy of <Swig Object of type 'std::shared_ptr< spot::twa_graph > *' at 0x7fbbb8570510> >"
       ]
      },
      "metadata": {},
@@ -1531,7 +1532,7 @@
        "</svg>\n"
       ],
       "text/plain": [
-       "<spot.twa_graph; proxy of <Swig Object of type 'std::shared_ptr< spot::twa_graph > *' at 0x7f0a9c20eb10> >"
+       "<spot.twa_graph; proxy of <Swig Object of type 'std::shared_ptr< spot::twa_graph > *' at 0x7fbbb850fae0> >"
       ]
      },
      "metadata": {},
@@ -1791,7 +1792,7 @@
        "</svg>\n"
       ],
       "text/plain": [
-       "<spot.twa_graph; proxy of <Swig Object of type 'std::shared_ptr< spot::twa_graph > *' at 0x7f0a9c20eea0> >"
+       "<spot.twa_graph; proxy of <Swig Object of type 'std::shared_ptr< spot::twa_graph > *' at 0x7fbbb850fb10> >"
       ]
      },
      "metadata": {},
@@ -2105,7 +2106,7 @@
        "</svg>\n"
       ],
       "text/plain": [
-       "<spot.twa_graph; proxy of <Swig Object of type 'std::shared_ptr< spot::twa_graph > *' at 0x7f0a9c20eea0> >"
+       "<spot.twa_graph; proxy of <Swig Object of type 'std::shared_ptr< spot::twa_graph > *' at 0x7fbbb850fb10> >"
       ]
      },
      "metadata": {},
@@ -2346,7 +2347,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.7.1"
+   "version": "3.7.3"
   }
  },
  "nbformat": 4,

tests/python/stutter.py

+# -*- mode: python; coding: utf-8 -*-
+# Copyright (C) 2019 Laboratoire de Recherche et Développement de
+# l'Epita (LRDE).
+#
+# 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/>.
+
+# Test that the spot.gen package works, in particular, we want
+# to make sure that the objects created from spot.gen methods
+# are usable with methods from the spot package.
+
+
+import spot
+
+def explain_stut(f):
+    f = spot.formula(f)
+    pos = spot.translate(f)
+    neg = spot.translate(spot.formula.Not(f))
+    word = spot.product(spot.closure(pos), spot.closure(neg)).accepting_word()
+    if word is None:
+        print(f, "is stutter invariant")
+        return
+    word.simplify()
+    # This line used to be missing, causing issue #388.
+    word.use_all_aps(pos.ap_vars())
+    waut = word.as_automaton()
+    aut = neg if waut.intersects(pos) else pos
+    word2 = spot.sl2(waut).intersecting_word(aut)
+    word2.simplify()
+    return(word, word2)
+
+# Test from issue #388
+w1, w2 = explain_stut('{(a:b) | (a;b)}|->Gc')
+assert str(w1) == 'a & !b & !c; cycle{!a & b & !c}'
+assert str(w2) == 'a & !b & !c; a & !b & !c; cycle{!a & b & !c}'