Speed up the obligation test.

* src/tgbaalgos/minimize.cc (minimize_obligation): Do not
minimize aut_neg_f, complement min_aut_f instead.
* src/tgbaalgos/minimize.hh: Adjust description.

ChangeLog

+2011-01-05  Alexandre Duret-Lutz  <adl@lrde.epita.fr>
+
+	Speed up the obligation test.
+
+	* src/tgbaalgos/minimize.cc (minimize_obligation): Do not
+	minimize aut_neg_f, complement min_aut_f instead.
+	* src/tgbaalgos/minimize.hh: Adjust description.
+
 2011-01-05  Alexandre Duret-Lutz  <adl@lrde.epita.fr>
 
 	* src/tgbaalgos/minimize.cc (minimize): Use the Loeding algorithm

src/tgbaalgos/minimize.cc

@@ -271,7 +271,7 @@ namespace spot
 
 
 
-  tgba_explicit* minimize(const tgba* a, bool monitor)
+  tgba_explicit_number* minimize(const tgba* a, bool monitor)
   {
     std::queue<hash_set*> todo;
     // The list of equivalent states.
@@ -496,7 +496,7 @@ namespace spot
 		      const ltl::formula* f, const tgba* aut_neg_f)
   {
     // WDBA minimization
-    tgba* min_aut_f = minimize(aut_f);
+    tgba_explicit_number* min_aut_f = minimize(aut_f);
 
     // If aut_f is a safety automaton, the WDBA minimization must be
     // correct.
@@ -545,20 +545,24 @@ namespace spot
       {
 	delete ec;
 	delete p;
-	tgba* min_aut_neg_f = minimize(aut_neg_f);
-	tgba* p = new tgba_product(aut_f, min_aut_neg_f);
+	// Complement the minimized WDBA.
+	min_aut_f->complement_all_acceptance_conditions();
+	tgba* p = new tgba_product(aut_f, min_aut_f);
 	emptiness_check* ec = couvreur99(p);
 	res = ec->check();
 
 	if (!res)
-	  // Finally, we are now sure that it was safe
-	  // to minimize the automaton.
-	  ok = true;
+	  {
+	    // Finally, we are now sure that it was safe
+	    // to minimize the automaton.
+	    ok = true;
+	    // Get the original automaton back.
+	    min_aut_f->complement_all_acceptance_conditions();
+	  }
 
 	delete res;
 	delete ec;
 	delete p;
-	delete min_aut_neg_f;
       }
     else
       {

src/tgbaalgos/minimize.hh

@@ -93,7 +93,7 @@ namespace spot
   /// \endverbatim
   /// (Note: although the above paper uses Spot, this function did not
   /// exist at that time.)
-  tgba_explicit* minimize(const tgba* a, bool monitor = false);
+  tgba_explicit_number* minimize(const tgba* a, bool monitor = false);
 
 
   /// \brief Minimize an automaton if it represents an obligation property.
@@ -138,7 +138,7 @@ namespace spot
   /// formula, then the result of \code minimize(aut) is returned.
   /// Otherwise, if \a aut_neg_f was not supplied but \a f was, \a
   /// aut_neg_f is built from the negation of \a f.  Then we check
-  /// that \code product(aut,minimize(aut_neg_f)) and \code
+  /// that \code product(aut,!minimize(aut_f)) and \code
   /// product(aut_neg_f,minize(aut)) are both empty.  If they are, the
   /// the minimization was sound.  (See the paper for full details.)
   const tgba* minimize_obligation(const tgba* aut_f,