* src/tgba/bdddict.cc, src/tgba/bdddict.cc (register_clone_acc):

New function.
* src/tgba/tgbaproduct.cc, src/tgba/tgbaproduct.hh: Use it to
distinguish acceptance conditions that are identical in both
operands.
* src/tgbatest/explpro4.test: New file.
* src/tgbatest/explpro2.test, src/tgbatest/Makefile.am: Adjust.

src/tgba/bdddict.cc

@@ -20,10 +20,14 @@
 // 02111-1307, USA.
 
 #include <ostream>
+#include <sstream>
 #include <cassert>
 #include <ltlvisit/clone.hh>
 #include <ltlvisit/destroy.hh>
 #include <ltlvisit/tostring.hh>
+#include <ltlvisit/tostring.hh>
+#include <ltlast/atomic_prop.hh>
+#include <ltlenv/defaultenv.hh>
 #include "bdddict.hh"
 
 namespace spot
@@ -140,6 +144,24 @@ namespace spot
   }
 
 
+  int
+  bdd_dict::register_clone_acc(int var, const void* for_me)
+  {
+    vf_map::iterator i = acc_formula_map.find(var);
+    assert(i != acc_formula_map.end());
+    std::ostringstream s;
+    // FIXME: We could be smarter and reuse unused "$n" numbers.
+    s << ltl::to_string(i->second) << "$"
+      << ++clone_counts[var];
+    ltl::formula* f =
+      ltl::atomic_prop::instance(s.str(),
+				 ltl::default_environment::instance());
+    int res = register_acceptance_variable(f, for_me);
+    ltl::destroy(f);
+    return res;
+  }
+
+
   int
   bdd_dict::register_anonymous_variables(int n, const void* for_me)
   {

src/tgba/bdddict.hh

@@ -54,6 +54,10 @@ namespace spot
     fv_map acc_map;		///< Maps acceptance conditions to BDD variables
     vf_map acc_formula_map;	///< Maps BDD variables to acceptance conditions
 
+    /// Clone counts.
+    typedef std::map<int, int> cc_map;
+    cc_map clone_counts;
+
     /// \brief Map Next variables to Now variables.
     ///
     /// Use with BuDDy's bdd_replace() function.
@@ -109,6 +113,13 @@ namespace spot
     ///   to convert this to a BDD.
     int register_acceptance_variable(const ltl::formula* f, const void* for_me);
 
+    /// \brief Clone an acceptance variable VAR for FOR_ME.
+    ///
+    /// This is used in products TGBAs when both operands share the
+    /// same acceptance variables but they need to be distinguished in
+    /// the result.
+    int register_clone_acc(int var, const void* for_me);
+
     /// \brief Register BDD variables as acceptance variables.
     ///
     /// Register all variables occurring in \a f as acceptance variables

src/tgba/tgbaproduct.cc

-// Copyright (C) 2003, 2004  Laboratoire d'Informatique de Paris 6 (LIP6),
+// Copyright (C) 2003, 2004, 2006  Laboratoire d'Informatique de Paris 6 (LIP6),
 // dpartement Systmes Rpartis Coopratifs (SRC), Universit Pierre
 // et Marie Curie.
 //
@@ -72,10 +72,11 @@ namespace spot
 
   tgba_succ_iterator_product::tgba_succ_iterator_product
   (tgba_succ_iterator* left, tgba_succ_iterator* right,
-   bdd left_neg, bdd right_neg)
+   bdd left_neg, bdd right_neg, bddPair* right_common_acc)
     : left_(left), right_(right),
       left_neg_(left_neg),
-      right_neg_(right_neg)
+      right_neg_(right_neg),
+      right_common_acc_(right_common_acc)
   {
   }
 
@@ -165,7 +166,8 @@ namespace spot
   bdd tgba_succ_iterator_product::current_acceptance_conditions() const
   {
     return ((left_->current_acceptance_conditions() & right_neg_)
-	    | (right_->current_acceptance_conditions() & left_neg_));
+	    | (bdd_replace(right_->current_acceptance_conditions(),
+			   right_common_acc_) & left_neg_));
   }
 
   ////////////////////////////////////////////////////////////
@@ -178,13 +180,31 @@ namespace spot
 
     bdd lna = left_->neg_acceptance_conditions();
     bdd rna = right_->neg_acceptance_conditions();
-    left_acc_complement_ = bdd_exist(lna, bdd_support(rna));
-    right_acc_complement_ = bdd_exist(rna, bdd_support(lna));
 
-    all_acceptance_conditions_ = ((left_->all_acceptance_conditions()
-				  & right_acc_complement_)
-				 | (right_->all_acceptance_conditions()
-				    & left_acc_complement_));
+    right_common_acc_ = bdd_newpair();
+    bdd common = bdd_exist(lna, bdd_exist(lna, rna));
+    while (common != bddtrue)
+      {
+	assert(bdd_high(common) == bddfalse);
+	int var = bdd_var(common);
+	int varclone = dict_->register_clone_acc(var, this);
+	bdd_setpair(right_common_acc_, var, varclone);
+	common = bdd_low(common);
+      }
+
+    bdd lac = left_->all_acceptance_conditions();
+    bdd rac = right_->all_acceptance_conditions();
+
+    rna = bdd_replace(rna, right_common_acc_);
+    rac = bdd_replace(rac, right_common_acc_);
+
+    left_acc_complement_ = lna;
+    assert(bdd_exist(lna, rna) == lna);
+    right_acc_complement_ = rna;
+    assert(bdd_exist(rna, lna) == rna);
+
+    all_acceptance_conditions_ = ((lac & right_acc_complement_)
+				  | (rac & left_acc_complement_));
     neg_acceptance_conditions_ = lna & rna;
 
     dict_->register_all_variables_of(&left_, this);
@@ -193,6 +213,7 @@ namespace spot
 
   tgba_product::~tgba_product()
   {
+    bdd_freepair(right_common_acc_);
     dict_->unregister_all_my_variables(this);
   }
 
@@ -226,7 +247,8 @@ namespace spot
 					       global_state, global_automaton);
     return new tgba_succ_iterator_product(li, ri,
 					  left_acc_complement_,
-					  right_acc_complement_);
+					  right_acc_complement_,
+					  right_common_acc_);
   }
 
   bdd

src/tgba/tgbaproduct.hh

@@ -80,7 +80,8 @@ namespace spot
   public:
     tgba_succ_iterator_product(tgba_succ_iterator* left,
 			       tgba_succ_iterator* right,
-			       bdd left_neg, bdd right_neg);
+			       bdd left_neg, bdd right_neg,
+			       bddPair* right_common_acc);
 
     virtual ~tgba_succ_iterator_product();
 
@@ -107,6 +108,7 @@ namespace spot
     bdd current_cond_;
     bdd left_neg_;
     bdd right_neg_;
+    bddPair* right_common_acc_;
     friend class tgba_product;
   };
 
@@ -153,6 +155,7 @@ namespace spot
     bdd right_acc_complement_;
     bdd all_acceptance_conditions_;
     bdd neg_acceptance_conditions_;
+    bddPair* right_common_acc_;
     // Disallow copy.
     tgba_product(const tgba_product&);
     tgba_product& operator=(const tgba_product&);

src/tgbatest/Makefile.am

-## Copyright (C) 2003, 2004, 2005  Laboratoire d'Informatique de Paris 6 (LIP6),
-## dpartement Systmes Rpartis Coopratifs (SRC), Universit Pierre
-## et Marie Curie.
+## Copyright (C) 2003, 2004, 2005, 2006 Laboratoire d'Informatique de
+## Paris 6 (LIP6), dpartement Systmes Rpartis Coopratifs (SRC),
+## Universit Pierre et Marie Curie.
 ##
 ## This file is part of Spot, a model checking library.
 ##
@@ -75,6 +75,7 @@ TESTS = \
   explprod.test \
   explpro2.test \
   explpro3.test \
+  explpro4.test \
   tripprod.test \
   mixprod.test \
   dupexp.test \

src/tgbatest/explpro2.test

 #!/bin/sh
-# Copyright (C) 2003, 2004, 2005  Laboratoire d'Informatique de Paris 6 (LIP6),
-# département Systèmes Répartis Coopératifs (SRC), Université Pierre
-# et Marie Curie.
+# Copyright (C) 2003, 2004, 2005, 2006 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.
 #
@@ -37,9 +37,9 @@ s1, s2, "b", p2;
 s1, s3, "a", p3;
 EOF
 
-cat >expected <<EOF
-acc = "p3" "p2" "p1";
-"s1 * s1", "s2 * s2", "b & !a", "p2" "p1";
+cat >expected <<'EOF'
+acc = "p2$1" "p3" "p2" "p1";
+"s1 * s1", "s2 * s2", "b & !a", "p2$1" "p1";
 "s1 * s1", "s3 * s3", "a & !b", "p3" "p2";
 EOF
 

src/tgbatest/explpro4.test

+#!/bin/sh
+# Copyright (C) 2006  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 2 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 Spot; see the file COPYING.  If not, write to the Free
+# Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+# 02111-1307, USA.
+
+
+. ./defs
+
+set -e
+
+cat >input1 <<EOF
+acc = p1;
+s1, s1, "a", p1;
+s1, s1, "!a", ;
+EOF
+
+cat >input2 <<EOF
+acc= p1;
+s1, s1, "a", ;
+s1, s1, "!a", p1;
+EOF
+
+cat >expected <<'EOF'
+acc = "p1$1" "p1";
+"s1 * s1", "s1 * s1", "a", "p1";
+"s1 * s1", "s1 * s1", "!a", "p1$1";
+EOF
+
+run 0 ./explprod input1 input2 > stdout
+cat stdout
+diff stdout expected
+rm input1 input2 stdout expected