stutter check: cleanup and add test cases

* src/ltltest/ltlfilt.test: Add more tests.
* src/ltltest/stutter.test: New test.
* src/ltltest/Makefile.am: Adjust.
* src/bin/ltlfilt.cc: Catch std::runtime_error.
* src/tgba/tgbasl.hh (make_tgbasl): New function.
* src/tgba/tgbagraph.hh (make_tgba_graph): Add another overload.
* src/tgbaalgos/stutter_invariance.cc,
src/tgbaalgos/stutter_invariance.hh: Take the algorithm version as an
optional integer, and call getenv() only once.
* bench/stutter/stutter_invariance_randomgraph.cc,
bench/stutter/stutter_invariance_formulas.cc: Simplify using the
above functions.

bench/stutter/stutter_invariance_formulas.cc

@@ -29,7 +29,6 @@
 #include "ltlvisit/length.hh"
 #include "misc/timer.hh"
 #include <argp.h>
-#include "error.h"
 
 const char argp_program_doc[] ="";
 
@@ -75,21 +74,17 @@ namespace
       bdd apdict = spot::ltl::atomic_prop_collect_as_bdd(f, a);
       bool res;
       bool prev = true;
-      for (char algo = '1'; algo <= '8'; ++algo)
+      for (int algo = 1; algo <= 8; ++algo)
         {
-          // set SPOT_STUTTER_CHECK environment variable
-          char algostr[2] = { 0 };
-          algostr[0] = algo;
-          setenv("SPOT_STUTTER_CHECK", algostr, true);
+          auto dup_a = spot::make_tgba_digraph(a);
+          auto dup_na = spot::make_tgba_digraph(na);
 
           spot::stopwatch sw;
-          auto dup_a = std::make_shared<spot::tgba_digraph>(a);
-          auto dup_na = std::make_shared<spot::tgba_digraph>(na);
-
           sw.start();
           res = spot::is_stutter_invariant(std::move(dup_a),
-                                           std::move(dup_na), apdict);
-          const double time = sw.stop();
+                                           std::move(dup_na),
+					   apdict, algo);
+          auto time = sw.stop();
 
           std::cout << formula << ", " << algo << ", " << ap->size() << ", "
 		    << num_states << ", " << res << ", " << time * 1000000 << std::endl;
@@ -100,7 +95,7 @@ namespace
         }
       f->destroy();
       nf->destroy();
-      delete(ap);
+      delete ap;
       return 0;
     }
   };

bench/stutter/stutter_invariance_randomgraph.cc

@@ -73,10 +73,10 @@ main()
                 vec.push_back(aut_pair_t(a, na));
               }
 
+	    char algostr[2] = { 0, 0 };
             for (char algo = '1'; algo <= '8'; ++algo)
               {
-                // Set SPOT_STUTTER_CHECK environment variable.
-                char algostr[2] = { 0 };
+                // Select the algorithm for checking stutter-invariance
 		algostr[0] = algo;
                 setenv("SPOT_STUTTER_CHECK", algostr, true);
 
@@ -86,18 +86,16 @@ main()
                 spot::stopwatch sw;
                 sw.start();
                 bool res;
-                for (auto& a: vec)
+                for (auto& a: dup)
                   res = spot::is_stutter_invariant(std::move(a.first),
                                                    std::move(a.second),
                                                    apdict);
-                const double time = sw.stop();
-
-                vec = dup;
+                auto time = sw.stop();
                 std::cout << algo << ", " << props_n << ", " << states_n
                           << ", " << res << ", " << time << std::endl;
               }
             spot::ltl::destroy_atomic_prop_set(*ap);
-            delete(ap);
+            delete ap;
           }
       }
 

src/bin/ltlfilt.cc

@@ -453,8 +453,16 @@ namespace
 	    check_cout();
 	    return !quiet;
 	  }
+      try
+	{
 	  return process_formula(f, filename, linenum);
 	}
+      catch (const std::runtime_error& e)
+	{
+	  error_at_line(2, 0, filename, linenum, "%s", e.what());
+	  SPOT_UNREACHABLE();
+	}
+    }
 
     int
     process_formula(const spot::ltl::formula* f,

src/ltltest/Makefile.am

@@ -112,7 +112,8 @@ TESTS = \
   reducpsl.test \
   reduccmp.test \
   uwrm.test \
-  eventuniv.test
+  eventuniv.test \
+  stutter.test
 
 distclean-local:
 	rm -rf $(TESTS:.test=.dir)

src/ltltest/ltlfilt.test

@@ -1,5 +1,5 @@
 #! /bin/sh
-# Copyright (C) 2013 Laboratoire de Recherche et Developement to
+# Copyright (C) 2013, 2014 Laboratoire de Recherche et Developement to
 # l'Epita (LRDE).
 #
 # This file is part of Spot, a model checking library.
@@ -41,6 +41,7 @@ F(b W GFa)
 GFa | Gb
 b W GFa
 !{a;b*;c}!
+!{a:b*:c}
 a U Fb
 G(a & Xb)
 Xa
@@ -75,6 +76,7 @@ F(GFa | Gb)
 F(b W GFa)
 GFa | Gb
 b W GFa
+!{a:b[*]:c}
 a U Fb
 F(a & !Xa & Xb)
 a & (b | c)
@@ -87,6 +89,7 @@ F(b W GFa)
 GFa | Gb
 b W GFa
 !a | X(!b R !c)
+!{a:b[*]:c}
 Fb
 G(a & Xb)
 Xa
@@ -110,6 +113,7 @@ EOF
 
 checkopt --obligation <<EOF
 !({a;b[*];c}!)
+!{a:b[*]:c}
 a U Fb
 G(a & Xb)
 Xa
@@ -118,6 +122,7 @@ a & (b | c)
 EOF
 
 checkopt --guarantee <<EOF
+!{a:b[*]:c}
 a U Fb
 Xa
 F(a & !Xa & Xb)
@@ -126,6 +131,7 @@ EOF
 
 checkopt -v --ltl <<EOF
 !({a;b[*];c}!)
+!{a:b[*]:c}
 EOF
 
 checkopt -v --stutter-invariant <<EOF
@@ -159,3 +165,16 @@ EOF
 
 run 0 ../../bin/ltlfilt -u --nnf --relabel-bool=pnn in >out
 diff exp out
+
+SPOT_STUTTER_CHECK=0 \
+../../bin/ltlfilt --stutter-invariant -f '!{a:b*:c}' 2> stderr && exit 1
+test $? = 2
+grep 'non-LTL' stderr
+
+SPOT_STUTTER_CHECK=555 \
+../../bin/ltlfilt --stutter-invariant -f '!{a:b*:c}' 2> stderr && exit 1
+test $? = 2
+grep 'invalid' stderr
+
+SPOT_STUTTER_CHECK=5 \
+../../bin/ltlfilt --stutter-invariant -f '!{a:b*:c}'

src/ltltest/stutter.test

@@ -0,0 +1,47 @@
+#! /bin/sh
+# -*- coding: utf-8 -*-
+# Copyright (C) 2013, 2014 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/>.
+
+
+# Check for the stutter-invariant formula detection
+. ./defs || exit 1
+
+set -e
+
+randltl=../../bin/randltl
+ltlfilt=../../bin/ltlfilt
+
+FILE=formulae
+rm -f $FILE
+for i in 10 12 14 16 18 20; do
+  $randltl --seed 0   --tree-size $i a b c       -n 100 >> $FILE
+  $randltl --seed 100 --tree-size $i a b c d e f -n 100 >> $FILE
+done
+
+# We do not check i=0, it is too slow.
+for i in 1 2 3 4 5 6 7 8; do
+    SPOT_STUTTER_CHECK=$i
+    export SPOT_STUTTER_CHECK
+    time $ltlfilt --stutter-invariant -F $FILE > res.$i
+done
+
+# All results should be equal
+for i in 2 3 4 5 6 7 8; do
+    diff res.1 res.$i
+done

src/tgba/tgbagraph.hh

@@ -450,6 +450,11 @@ namespace spot
     return std::make_shared<tgba_digraph>(dict);
   }
 
+  inline tgba_digraph_ptr make_tgba_digraph(const tgba_digraph_ptr& aut)
+  {
+    return std::make_shared<tgba_digraph>(aut);
+  }
+
   inline tgba_digraph_ptr make_tgba_digraph(const const_tgba_digraph_ptr& aut)
   {
     return std::make_shared<tgba_digraph>(aut);

src/tgba/tgbasl.hh

@@ -44,6 +44,13 @@ namespace spot
     const_tgba_ptr a_;
     bdd aps_;
   };
+
+  typedef std::shared_ptr<tgbasl> tgbasl_ptr;
+
+  inline tgbasl_ptr make_tgbasl(const const_tgba_ptr& aut, bdd ap)
+  {
+    return std::make_shared<tgbasl>(aut, ap);
+  }
 }
 
 #endif

src/tgbaalgos/stutter_invariance.cc

@@ -32,102 +32,94 @@
 
 namespace spot
 {
+  // The stutter check algorithm to use can be overridden via an
+  // environment variable.
+  static int default_stutter_check_algorithm()
+  {
+    static const char* stutter_check = getenv("SPOT_STUTTER_CHECK");
+    if (stutter_check)
+      {
+	char* endptr;
+	long res = strtol(stutter_check, &endptr, 10);
+	if (*endptr || res < 0 || res > 8)
+	  throw
+	    std::runtime_error("invalid value for SPOT_STUTTER_CHECK.");
+	return res;
+      }
+    else
+      {
+	return 8;     // The best variant, according to our benchmarks.
+      }
+  }
+
   bool
   is_stutter_invariant(const ltl::formula* f)
   {
-      const char* stutter_check = getenv("SPOT_STUTTER_CHECK");
-      char algo = stutter_check ? stutter_check[0] : '1';
     if (f->is_ltl_formula() && f->is_X_free())
       return true;
 
-      if (algo == '0')
-        {
-          // Syntactic checking.
-          if (f->is_ltl_formula())
+    int algo = default_stutter_check_algorithm();
+
+    if (algo == 0) // Etessami's check via syntactic transformation.
       {
+	if (!f->is_ltl_formula())
+	  throw std::runtime_error("Cannot use the syntactic "
+				   "stutter-invariance check "
+				   "for non-LTL formulas");
 	const ltl::formula* g = remove_x(f);
 	ltl::ltl_simplifier ls;
 	bool res = ls.are_equivalent(f, g);
 	g->destroy();
 	return res;
       }
-          else
-            {
-              throw std::runtime_error("Cannot use the syntactic-based " \
-                                       "approach to stutter-invariance " \
-                                       "checking on non-ltl formula");
-            }
-        }
+
+    // Prepare for an automata-based check.
     const ltl::formula* nf = ltl::unop::instance(ltl::unop::Not, f->clone());
     translator trans;
-      tgba_digraph_ptr aut_f = trans.run(f);
-      tgba_digraph_ptr aut_nf = trans.run(nf);
+    auto aut_f = trans.run(f);
+    auto aut_nf = trans.run(nf);
     bdd aps = atomic_prop_collect_as_bdd(f, aut_f);
     nf->destroy();
-      return is_stutter_invariant(std::move(aut_f), std::move(aut_nf), aps);
+    return is_stutter_invariant(std::move(aut_f), std::move(aut_nf), aps, algo);
   }
 
   bool
   is_stutter_invariant(tgba_digraph_ptr&& aut_f,
-                       tgba_digraph_ptr&& aut_nf, bdd aps)
+                       tgba_digraph_ptr&& aut_nf, bdd aps, int algo)
   {
-      const char* stutter_check = getenv("SPOT_STUTTER_CHECK");
-      char algo = stutter_check ? stutter_check[0] : '8';
+    if (algo == 0)
+      algo = default_stutter_check_algorithm();
 
     switch (algo)
       {
-          // sl(aut_f) x sl(aut_nf)
-        case '1':
-            {
+      case 1: // sl(aut_f) x sl(aut_nf)
 	return product(sl(std::move(aut_f), aps),
 		       sl(std::move(aut_nf), aps))->is_empty();
-            }
-          // sl(cl(aut_f)) x aut_nf
-        case '2':
-            {
+      case 2: // sl(cl(aut_f)) x aut_nf
 	return product(sl(closure(std::move(aut_f)), aps),
 		       std::move(aut_nf))->is_empty();
-            }
-          // (cl(sl(aut_f)) x aut_nf
-        case '3':
-            {
+      case 3: // (cl(sl(aut_f)) x aut_nf
 	return product(closure(sl(std::move(aut_f), aps)),
 		       std::move(aut_nf))->is_empty();
-            }
-          // sl2(aut_f) x sl2(aut_nf)
-        case '4':
-            {
+      case 4: // sl2(aut_f) x sl2(aut_nf)
 	return product(sl2(std::move(aut_f), aps),
 		       sl2(std::move(aut_nf), aps))->is_empty();
-            }
-          // sl2(cl(aut_f)) x aut_nf
-        case '5':
-            {
+      case 5: // sl2(cl(aut_f)) x aut_nf
 	return product(sl2(closure(std::move(aut_f)), aps),
 		       std::move(aut_nf))->is_empty();
-            }
-          // (cl(sl2(aut_f)) x aut_nf
-        case '6':
-            {
+      case 6: // (cl(sl2(aut_f)) x aut_nf
 	return product(closure(sl2(std::move(aut_f), aps)),
 		       std::move(aut_nf))->is_empty();
-            }
-          // on-the-fly sl(aut_f) x sl(aut_nf)
-        case '7':
-            {
-              auto slf = std::make_shared<tgbasl>(aut_f, aps);
-              auto slnf = std::make_shared<tgbasl>(aut_nf, aps);
-              return product(slf, slnf)->is_empty();
-            }
-          // cl(aut_f) x cl(aut_nf)
-        case '8':
-            {
+      case 7: // on-the-fly sl(aut_f) x sl(aut_nf)
+	return product(make_tgbasl(aut_f, aps),
+		       make_tgbasl(aut_nf, aps))->is_empty();
+      case 8: // cl(aut_f) x cl(aut_nf)
 	return product(closure(std::move(aut_f)),
 		       closure(std::move(aut_nf)))->is_empty();
-            }
       default:
-          throw std::runtime_error("invalid value for SPOT_STUTTER_CHECK.");
-          break;
+	throw std::runtime_error("invalid algorithm number for "
+				 "is_stutter_invariant()");
+	SPOT_UNREACHABLE();
       }
   }
 }

src/tgbaalgos/stutter_invariance.hh

@@ -30,7 +30,8 @@ namespace spot
 
   SPOT_API bool
   is_stutter_invariant(tgba_digraph_ptr&& aut_f,
-		       tgba_digraph_ptr&& aut_nf, bdd aps);
+		       tgba_digraph_ptr&& aut_nf, bdd aps,
+		       int algo = 0);
 }
 
 #endif