restructure the complementation code

The previous code was sometime doing the work of remove_fin() in
addition to complementing the acceptance conditions.  This separate
the two operations clearly.  Also the specialized code for
complementing weak automata is now a specialized code for remove_fin()
on weak automata.

* src/twaalgos/dtgbacomp.hh, src/twaalgos/dtgbacomp.cc: Rename as ...
* src/twaalgos/complement.hh, src/twaalgos/complement.cc: ... these.
* src/twaalgos/Makefile.am: Adjust.
* src/twaalgos/complement.hh (dtgba_complement): Rename as ...
(dtwa_complement): ... this, and restrict the purpose to completion
and accetance complementation.  Further acceptance simplification
can be done with remove_fin() and to_generalized_buchi().
* src/twaalgos/remfin.cc (remove_fin): Specialize handling of weak
automata using the code that was originally in dtgba_complement().
Also mark the output as state-based when the input has to Inf.
* src/twaalgos/postproc.cc, src/twaalgos/postproc.hh: Make sure
scc_filter is always called after to_generalized_buchi().
* bench/stutter/stutter_invariance_randomgraph.cc,
src/bin/ltlcross.cc, src/tests/ikwiad.cc, src/twaalgos/minimize.cc,
src/twaalgos/powerset.cc, src/twaalgos/stutter.cc: Adjust usage.
* src/tests/dstar.test, src/tests/ltl2dstar4.test,
src/tests/remfin.test: Adjust expected outputs.
* wrap/python/spot_impl.i: Export dtwa_complement().

NEWS

@@ -1,8 +1,18 @@
 New in spot 1.99.4a (not yet released)
 
+  * Rename dtgba_complement() as dtwa_complement(), rename the header
+    as complement.hh, and restrict the purpose of this function to
+    just complete the automaton and complement its acceptance
+    condition.   Any further acceptance condition transformation
+    can be done with to_generalized_buchi() or remove_fin().
+
+  * The remove_fin() has learnt how to better deal with automata that
+    are declared as weak.  This code was previously in
+    dtgba_complement().
+
   Python:
 
-  * Add bindings for complete().
+  * Add bindings for complete() and dtwa_complement()
   * Formulas now have a custom __format__ function.  See
     https://spot.lrde.epita.fr/tut01.html for examples.
 

bench/stutter/stutter_invariance_randomgraph.cc

@@ -19,7 +19,8 @@
 
 #include "misc/timer.hh"
 #include "tl/apcollect.hh"
-#include "twaalgos/dtgbacomp.hh"
+#include "twaalgos/complement.hh"
+#include "twaalgos/remfin.hh"
 #include "twaalgos/randomgraph.hh"
 #include "twaalgos/dot.hh"
 #include "twaalgos/product.hh"
@@ -80,7 +81,7 @@ main(int argc, char** argv)
 					  true);
 	    }
 	  while (a->is_empty());
-	  auto na = spot::dtgba_complement(a);
+	  auto na = spot::remove_fin(spot::dtwa_complement(a));
 
 	  std::cout << d << ',' << props_n << ',' << seed;
 	  stats.print(a);

src/bin/ltlcross.cc

@@ -53,7 +53,7 @@
 #include "twaalgos/isweakscc.hh"
 #include "twaalgos/reducerun.hh"
 #include "twaalgos/word.hh"
-#include "twaalgos/dtgbacomp.hh"
+#include "twaalgos/complement.hh"
 #include "twaalgos/cleanacc.hh"
 #include "misc/formater.hh"
 #include "twaalgos/stats.hh"
@@ -1016,7 +1016,7 @@ namespace
 	  if (!no_complement && pos[n]
 	      && ((want_stats && !(*pstats)[n].nondeterministic)
 		  || (!want_stats && is_deterministic(pos[n]))))
-	    comp_pos[n] = dtgba_complement(pos[n]);
+	    comp_pos[n] = dtwa_complement(pos[n]);
 	}
 
       // ---------- Negative Formula ----------
@@ -1056,7 +1056,7 @@ namespace
 	      if (!no_complement && neg[n]
 		  && ((want_stats && !(*nstats)[n].nondeterministic)
 		      || (!want_stats && is_deterministic(neg[n]))))
-		comp_neg[n] = dtgba_complement(neg[n]);
+		comp_neg[n] = dtwa_complement(neg[n]);
 	    }
 	}
 

src/tests/dstar.test

@@ -244,7 +244,7 @@ digraph G {
   node [shape="circle"]
   I [label="", style=invis, width=0]
   I -> 0
-  0 [label="0"]
+  0 [label="0", peripheries=2]
   0 -> 1 [label="!a & !b"]
   0 -> 2 [label="a & !b"]
   1 [label="1", peripheries=2]

src/tests/ikwiad.cc

@@ -60,7 +60,8 @@
 #include "twaalgos/simulation.hh"
 #include "twaalgos/compsusp.hh"
 #include "twaalgos/powerset.hh"
-#include "twaalgos/dtgbacomp.hh"
+#include "twaalgos/complement.hh"
+#include "twaalgos/remfin.hh"
 #include "twaalgos/complete.hh"
 #include "twaalgos/dtbasat.hh"
 #include "twaalgos/dtgbasat.hh"
@@ -338,7 +339,7 @@ checked_main(int argc, char** argv)
   bool opt_determinize = false;
   unsigned opt_determinize_threshold = 0;
   unsigned opt_o_threshold = 0;
-  bool opt_dtgbacomp = false;
+  bool opt_dtwacomp = false;
   bool reject_bigger = false;
   bool opt_monitor = false;
   bool containment = false;
@@ -411,7 +412,7 @@ checked_main(int argc, char** argv)
 	}
       else if (!strcmp(argv[formula_index], "-DC"))
 	{
-	  opt_dtgbacomp = true;
+	  opt_dtwacomp = true;
 	}
       else if (!strncmp(argv[formula_index], "-DS", 3)
 	       || !strncmp(argv[formula_index], "-DT", 3))
@@ -1203,14 +1204,14 @@ checked_main(int argc, char** argv)
 	    a = satminimized;
 	}
 
-      if (opt_dtgbacomp)
+      if (opt_dtwacomp)
 	{
-	  tm.start("DTGBA complement");
+	  tm.start("DTωA complement");
-	  a = dtgba_complement(ensure_digraph(a));
+	  a = remove_fin(dtwa_complement(ensure_digraph(a)));
-	  tm.stop("DTGBA complement");
+	  tm.stop("DTωA complement");
 	}
 
-      if (opt_determinize || opt_dtgbacomp || opt_dtbasat >= 0
+      if (opt_determinize || opt_dtwacomp || opt_dtbasat >= 0
 	  || opt_dtgbasat >= 0)
 	{
 	  if (scc_filter && (reduction_dir_sim || reduction_rev_sim))

src/tests/ltl2dstar4.test

@@ -41,13 +41,13 @@ $ltlfilt -f '(GFa -> GFb) & (GFc -> GFd)' -l |
 ltl2dstar --ltl2nba=spin:$ltl2tgba@-s $STR - - |
 $autfilt --tgba --stats '%S %E %A %s %e %t %a %d' |
 tee out
-test "`cat out`" = '9 144 4 25 416 416 2 0'
+test "`cat out`" = '9 144 4 25 149 416 2 0'
 
 $ltlfilt -f '(GFa -> GFb) & (GFc -> GFd)' -l |
 ltl2dstar --ltl2nba=spin:$ltl2tgba@-s $STR - - |
 SPOT_STREETT_CONV_MIN=1 $autfilt --tgba --stats '%S %E %A %s %e %t %a %d' |
 tee out
-test "`cat out`" = '9 144 4 25 482 482 2 0'
+test "`cat out`" = '9 144 4 25 218 482 2 0'
 
 
 LTL2DSTAR="ltl2dstar $STR --ltl2nba=spin:$ltl2tgba@-s %L"

src/tests/remfin.test

@@ -218,20 +218,13 @@ Acceptance: 1 Inf(0)
 properties: trans-labels explicit-labels state-acc
 --BODY--
 State: 0
-[0&1] 0
+[t] 0
-[!0&!1] 0
+[!0] 1
-[!0&1] 0
+[!1] 2
-[0&!1] 0
-[!0&!1] 1
-[!0&1] 1
-[!0&!1] 2
-[0&!1] 2
 State: 1 {0}
-[!0&!1] 1
+[!0] 1
-[!0&1] 1
 State: 2 {0}
-[!0&!1] 2
+[!1] 2
-[0&!1] 2
 --END--
 HOA: v1
 States: 4
@@ -275,7 +268,7 @@ State: 2
 [!1] 0
 [0&!1] 1 {0}
 [!0&!1] 2 {0}
-[!0&!1] 3 {0}
+[!0&!1] 3
 State: 3
 [!0&!1] 3 {0 1 4}
 --END--
@@ -325,31 +318,30 @@ Acceptance: 2 Inf(1) | Inf(0)
 properties: trans-labels explicit-labels state-acc
 --BODY--
 State: 0
-[!0] 6
 [0] 0
+[!0] 6
 [0] 8
 [0] 9
 State: 1 {0 1}
-[!0] 3
+[t] 3
-[0] 3
 State: 2 {0 1}
-[!0] 5
 [0] 1
+[!0] 5
 State: 3 {0 1}
-[!0] 6
 [0] 0
+[!0] 6
 State: 4 {0 1}
-[!0] 6
 [0] 4
+[!0] 6
 State: 5 {0 1}
-[!0] 7
 [0] 3
+[!0] 7
 State: 6
-[!0] 6
 [0] 0
-State: 7 {1}
 [!0] 6
+State: 7 {1}
 [0] 4
+[!0] 6
 State: 8
 [0] 8
 State: 9 {1}
@@ -547,68 +539,61 @@ Acceptance: 1 Inf(0)
 properties: trans-labels explicit-labels state-acc
 --BODY--
 State: 0
-[0&1] 0
+[t] 0
-[!0&!1] 0
+[!0] 1
-[!0&1] 0
+[!1] 2
-[0&!1] 0
-[!0&!1] 1
-[!0&1] 1
-[!0&!1] 2
-[0&!1] 2
 State: 1 {0}
-[!0&!1] 1
+[!0] 1
-[!0&1] 1
 State: 2 {0}
-[!0&!1] 2
+[!1] 2
-[0&!1] 2
 --END--
 HOA: v1
 States: 4
 Start: 0
 AP: 2 "a" "b"
-acc-name: generalized-Buchi 2
+acc-name: Buchi
-Acceptance: 2 Inf(0)&Inf(1)
+Acceptance: 1 Inf(0)
 properties: trans-labels explicit-labels trans-acc
 --BODY--
 State: 0
-[t] 0 {0 1}
+[t] 0 {0}
-[0] 1 {0 1}
+[0] 1 {0}
-[!0] 2 {0 1}
+[!0] 2 {0}
 State: 1
-[1] 0 {1}
+[1] 0
-[0&1] 1 {1}
+[0&1] 1
-[!0&1] 2 {0 1}
+[!0&1] 2 {0}
 State: 2
 [!1] 0
 [0&!1] 1
 [!0&!1] 2
 [!0&!1] 3
 State: 3
-[!0&!1] 3 {0 1}
+[!0&!1] 3 {0}
 --END--
 HOA: v1
 States: 4
 Start: 0
 AP: 2 "a" "b"
-acc-name: generalized-Buchi 2
+acc-name: Buchi
-Acceptance: 2 Inf(0)&Inf(1)
+Acceptance: 1 Inf(0)
 properties: trans-labels explicit-labels trans-acc
 --BODY--
 State: 0
-[t] 0 {1}
+[t] 0
-[0] 1 {1}
+[0] 1
-[!0] 2 {0 1}
+[!0] 2 {0}
 State: 1
-[1] 0 {1}
+[1] 0
-[0&1] 1 {0 1}
+[0&1] 1 {0}
-[!0&1] 2 {0 1}
+[!0&1] 2 {0}
 State: 2
 [!1] 0
-[0&!1] 1 {0 1}
+[0&!1] 1 {0}
-[!0&!1] 2 {0 1}
+[!0&!1] 2 {0}
-[!0&!1] 3 {0 1}
+[!0&!1] 3
 State: 3
-[!0&!1] 3 {0 1}
+[!0&!1] 3 {0}
 --END--
 HOA: v1
 States: 1
@@ -646,47 +631,42 @@ State: 0
 [!0] 0
 [0] 1
 State: 1 {0}
-[!0] 1
+[t] 1
-[0] 1
 --END--
 HOA: v1
-States: 10
+States: 9
 Start: 2
 AP: 1 "p1"
 acc-name: Buchi
 Acceptance: 1 Inf(0)
-properties: trans-labels explicit-labels state-acc
+properties: trans-labels explicit-labels trans-acc
 --BODY--
 State: 0
-[!0] 6
 [0] 0
+[!0] 6
 [0] 8
-[0] 9
+State: 1
-State: 1 {0}
+[t] 3
-[!0] 3
+State: 2
-[0] 3
-State: 2 {0}
-[!0] 5
 [0] 1
-State: 3 {0}
+[!0] 5
-[!0] 6
+State: 3
 [0] 0
-State: 4 {0}
 [!0] 6
-[0] 4
+State: 4
-State: 5 {0}
+[0] 4 {0}
-[!0] 7
+[!0] 6
+State: 5
 [0] 3
+[!0] 7
 State: 6
-[!0] 6
 [0] 0
-State: 7 {0}
 [!0] 6
-[0] 4
+State: 7
+[0] 4 {0}
+[!0] 6
 State: 8
-[0] 8
+[0] 8 {0}
-State: 9 {0}
-[0] 9
 --END--
 HOA: v1
 States: 15
@@ -694,83 +674,75 @@ Start: 13
 AP: 2 "p1" "p0"
 acc-name: Buchi
 Acceptance: 1 Inf(0)
-properties: trans-labels explicit-labels state-acc
+properties: trans-labels explicit-labels trans-acc
 --BODY--
-State: 0 {0}
+State: 0
+[0&1] 0 {0}
+[!0&1] 1 {0}
+[0&!1] 11 {0}
 [!0&!1] 12
-[0&!1] 11
+State: 1
-[!0&1] 1
+[0&1] 0 {0}
-[0&1] 0
+[!0&1] 1 {0}
-State: 1 {0}
+[0&!1] 11 {0}
 [!0&!1] 12
-[0&!1] 11
+State: 2
-[!0&1] 1
+[!0&1] 2 {0}
-[0&1] 0
-State: 2 {0}
-[!0&!1] 10
-[0&!1] 11
-[!0&1] 2
 [0&1] 9
-State: 3 {0}
+[!0&!1] 10 {0}
+[0&!1] 11 {0}
+State: 3
+[!0&1] 1 {0}
+[0&1] 3 {0}
+[0&!1] 11 {0}
 [!0&!1] 12
-[0&!1] 11
+State: 4
-[!0&1] 1
+[!0&1] 4 {0}
-[0&1] 3
+[0&1] 7 {0}
-State: 4 {0}
+[!1] 12
-[!0&!1] 12
+State: 5
-[0&!1] 12
+[!0&1] 5 {0}
-[!0&1] 4
-[0&1] 7
-State: 5 {0}
-[!0&!1] 10
-[0&!1] 12
-[!0&1] 5
 [0&1] 8
-State: 6 {0}
+[!0&!1] 10 {0}
-[!0&!1] 12
-[0&!1] 11
-[!0&1] 4
-[0&1] 6
-State: 7 {0}
-[!0&!1] 12
 [0&!1] 12
-[!0&1] 4
+State: 6
-[0&1] 7
+[!0&1] 4 {0}
+[0&1] 6 {0}
+[0&!1] 11 {0}
+[!0&!1] 12
+State: 7
+[!0&1] 4 {0}
+[0&1] 7 {0}
+[!1] 12
 State: 8
-[!0&!1] 12
+[1] 8
-[0&!1] 12
+[!1] 12
-[!0&1] 8
+[1] 14
-[0&1] 8
-[!0&1] 14
-[0&1] 14
 State: 9
-[!0&!1] 12
-[0&!1] 11
 [!0&1] 1
 [0&1] 3
-State: 10 {0}
-[!0&!1] 10
-[0&!1] 12
-[!0&1] 5
-[0&1] 8
-State: 11 {0}
-[!0&!1] 12
 [0&!1] 11
+[!0&!1] 12
+State: 10
+[!0&1] 5 {0}
+[0&1] 8
+[!0&!1] 10 {0}
+[0&!1] 12
+State: 11
+[0&1] 6 {0}
 [!0&1] 8
-[0&1] 6
+[0&!1] 11 {0}
+[!0&!1] 12
 State: 12
-[!0&!1] 12
+[1] 8
-[0&!1] 12
+[!1] 12
-[!0&1] 8
-[0&1] 8
 State: 13
-[!0&!1] 10
-[0&!1] 11
 [!0&1] 2
 [0&1] 3
-State: 14 {0}
+[!0&!1] 10
-[!0&1] 14
+[0&!1] 11
-[0&1] 14
+State: 14
+[1] 14 {0}
 --END--
 HOA: v1
 States: 4
@@ -797,44 +769,26 @@ State: 3 {0}
 [!0&1] 3
 --END--
 HOA: v1
-States: 6
+States: 5
-Start: 5
+Start: 4
 AP: 2 "p0" "p1"
 acc-name: Buchi
 Acceptance: 1 Inf(0)
-properties: trans-labels explicit-labels state-acc complete
+properties: trans-labels explicit-labels trans-acc deterministic
-properties: deterministic
 --BODY--
 State: 0
-[!0&!1] 0
+[0] 1
-[0&!1] 0
-[!0&1] 0
-[0&1] 0
 State: 1
-[!0&!1] 0
+[t] 1 {0}
-[0&!1] 2
+State: 2
 [!0&1] 0
-[0&1] 2
+[0] 1 {0}
-State: 2 {0}
+[!0&!1] 2 {0}
-[!0&!1] 2
+State: 3
-[0&!1] 2
+[1] 0
-[!0&1] 2
+[!1] 2
-[0&1] 2
-State: 3 {0}
-[!0&!1] 3
-[0&!1] 2
-[!0&1] 1
-[0&1] 2
 State: 4
-[!0&!1] 3
+[t] 3
-[0&!1] 3
-[!0&1] 1
-[0&1] 1
-State: 5
-[!0&!1] 4
-[0&!1] 4
-[!0&1] 4
-[0&1] 4
 --END--
 HOA: v1
 States: 5
@@ -845,24 +799,18 @@ Acceptance: 1 Inf(0)
 properties: trans-labels explicit-labels state-acc
 --BODY--
 State: 0
-[!0&!1] 2
 [0&!1] 0
-[!0&1] 2
+[!0] 2
 [0&1] 3
 State: 1
-[!0&!1] 2
 [0&!1] 1
-[!0&1] 2
+[!0 | 1] 2
-[0&1] 2
 State: 2 {0}
-[!0&!1] 2
 [0&!1] 0
-[!0&1] 2
+[!0 | 1] 2
-[0&1] 2
 State: 3
-[!0&!1] 2
 [0&!1] 0
-[!0&1] 2
+[!0] 2
 [0&1] 3
 [0&1] 4
 State: 4 {0}

src/twaalgos/Makefile.am

@@ -33,10 +33,10 @@ twaalgos_HEADERS = \
   canonicalize.hh \
   cleanacc.hh \
   complete.hh \
+  complement.hh \
   compsusp.hh \
   copy.hh \
   cycles.hh \
-  dtgbacomp.hh \
   degen.hh \
   dot.hh \
   dtbasat.hh \
@@ -90,10 +90,10 @@ libtwaalgos_la_SOURCES = \
   canonicalize.cc \
   cleanacc.cc \
   complete.cc \
+  complement.cc \
   compsusp.cc \
   copy.cc \
   cycles.cc \
-  dtgbacomp.cc \
   degen.cc \
   dot.cc \
   dtbasat.cc \

src/twaalgos/complement.cc

@@ -0,0 +1,35 @@
+// -*- coding: utf-8 -*-
+// Copyright (C) 2013, 2014, 2015 Laboratoire de Recherche et
+// Développement de l'Epita.
+//
+// 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/>.
+
+#include "complement.hh"
+#include "sccinfo.hh"
+#include "complete.hh"
+#include "cleanacc.hh"
+
+namespace spot
+{
+  twa_graph_ptr
+  dtwa_complement(const const_twa_graph_ptr& aut)
+  {
+    // Simply complete the automaton, and complement its acceptance.
+    auto res = cleanup_acceptance_here(complete(aut));
+    res->set_acceptance(res->num_sets(), res->get_acceptance().complement());
+    return res;
+  }
+}

src/twaalgos/complement.hh

@@ -23,13 +23,19 @@
 
 namespace spot
 {
-  /// \brief Complement a deterministic TGBA
+  /// \brief Complement a deterministic TωA
   ///
-  /// The automaton \a aut should be deterministic.  It does no need
+  /// The automaton \a aut should be deterministic.  It will be
-  /// to be complete.  Acceptance can be transition-based, or
+  /// completed if it isn't already.  In these conditions,
-  /// state-based.  Unless the input automaton is marked as weak (in
+  /// complementing the automaton can be done by just complementing
-  /// which case the output will also be weak and deterministic) the
+  /// the acceptance condition.
-  /// resulting automaton is very unlikely to be deterministic.
+  ///
+  /// In particular, this implies that an input that use
+  /// generalized Büchi will be output as generalized co-Büchi.
+  ///
+  /// Functions like to_generalized_buchi() or remove_fin() are
+  /// frequently called after dtwa_complement() to obtain an easier
+  /// acceptance condition (maybe at the cost of loosing determinism.)
   SPOT_API twa_graph_ptr
-  dtgba_complement(const const_twa_graph_ptr& aut);
+  dtwa_complement(const const_twa_graph_ptr& aut);
 }

src/twaalgos/dtgbacomp.cc

@@ -1,187 +0,0 @@
-// -*- coding: utf-8 -*-
-// Copyright (C) 2013, 2014, 2015 Laboratoire de Recherche et
-// Développement de l'Epita.
-//
-// 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/>.
-
-#include "dtgbacomp.hh"
-#include "sccinfo.hh"
-#include "complete.hh"
-#include "cleanacc.hh"
-
-namespace spot
-{
-  namespace
-  {
-    static twa_graph_ptr
-    dtgba_complement_nonweak(const const_twa_graph_ptr& aut)
-    {
-      // Clone the original automaton.
-      auto res = make_twa_graph(aut,
-				{ false, // state based
-				    false, // inherently_weak
-				    false, // deterministic
-				    true,  // stutter inv.
-				    });
-      // Copy the old acceptance condition before we replace it.
-      acc_cond oldacc = aut->acc(); // Copy it!
-
-      // We will modify res in place, and the resulting
-      // automaton will only have one acceptance set.
-      // This changes aut->acc();
-      res->set_buchi();
-      // The resulting automaton is weak.
-      res->prop_inherently_weak();
-      res->prop_state_based_acc();
-
-      unsigned num_sets = oldacc.num_sets();
-      unsigned n = res->num_states();
-      // We will duplicate the automaton as many times as we have
-      // acceptance sets, and we need one extra sink state.
-      res->new_states(num_sets * n + 1);
-      unsigned sink = res->num_states() - 1;
-      // The sink state has an accepting self-loop.
-      res->new_acc_edge(sink, sink, bddtrue);
-
-      for (unsigned src = 0; src < n; ++src)
-	{
-	  // Keep track of all conditions on edge leaving state
-	  // SRC, so we can complete it.
-	  bdd missingcond = bddtrue;
-	  for (auto& t: res->out(src))
-	    {
-	      if (t.dst >= n)	// Ignore edges we added.
-		break;
-	      missingcond -= t.cond;
-	      acc_cond::mark_t curacc = t.acc;
-	      // The original edge must not accept anymore.
-	      t.acc = 0U;
-
-	      // Edge that were fully accepting are never cloned.
-	      if (oldacc.accepting(curacc))
-		continue;
-	      // Save t.cond and t.dst as the reference to t
-	      // is invalided by calls to new_edge().
-	      unsigned dst = t.dst;
-	      bdd cond = t.cond;
-
-	      // Iterate over all the acceptance conditions in 'curacc',
-	      // an duplicate it for each clone for which it does not
-	      // belong to the acceptance set.
-	      unsigned add = 0;
-	      for (unsigned set = 0; set < num_sets; ++set)
-		{
-		  add += n;
-		  if (!oldacc.has(curacc, set))
-		    {
-		      // Clone the edge
-		      res->new_acc_edge(src + add, dst + add, cond);
-		      assert(dst + add < sink);
-		      // Using `t' is disallowed from now on as it is a
-		      // reference to a edge that may have been
-		      // reallocated.
-
-		      // At least one edge per cycle should have a
-		      // nondeterministic copy from the original clone.
-		      // We use state numbers to select it, as any cycle
-		      // is guaranteed to have at least one edge
-		      // with dst <= src.  FIXME: Computing a feedback
-		      // arc set would be better.
-		      if (dst <= src)
-			res->new_edge(src, dst + add, cond);
-		    }
-		}
-	      assert(add == num_sets * n);
-	    }
-	  // Complete the original automaton.
-	  if (missingcond != bddfalse)
-	    res->new_edge(src, sink, missingcond);
-	}
-      res->merge_edges();
-      res->purge_dead_states();
-      return res;
-    }
-
-    static twa_graph_ptr
-    dtgba_complement_weak(const const_twa_graph_ptr& aut)
-    {
-      // Clone the original automaton.
-      auto res = make_twa_graph(aut,
-				{ true, // state based
-				    true, // inherently weak
-				    true, // determinisitic
-				    true,  // stutter inv.
-				    });
-      scc_info si(res);
-
-      // We will modify res in place, and the resulting
-      // automaton will only have one acceptance set.
-      acc_cond::mark_t all_acc = res->set_buchi();
-      res->prop_state_based_acc();
-
-      unsigned sink = res->num_states();
-
-      for (unsigned src = 0; src < sink; ++src)
-	{
-	  acc_cond::mark_t acc = 0U;
-	  unsigned scc = si.scc_of(src);
-	  if (si.is_rejecting_scc(scc) && !si.is_trivial(scc))
-	    acc = all_acc;
-
-	  // Keep track of all conditions on edge leaving state
-	  // SRC, so we can complete it.
-	  bdd missingcond = bddtrue;
-	  for (auto& t: res->out(src))
-	    {
-	      missingcond -= t.cond;
-	      t.acc = acc;
-	    }
-	  // Complete the original automaton.
-	  if (missingcond != bddfalse)
-	    {
-	      if (res->num_states() == sink)
-		{
-		  res->new_state();
-		  res->new_acc_edge(sink, sink, bddtrue);
-		}
-	      res->new_edge(src, sink, missingcond);
-	    }
-	}
-      //res->merge_edges();
-      return res;
-    }
-  }
-
-  twa_graph_ptr dtgba_complement(const const_twa_graph_ptr& aut)
-  {
-    if (aut->acc().is_generalized_buchi())
-      {
-	if (aut->is_inherently_weak())
-	  return dtgba_complement_weak(aut);
-	else
-	  return dtgba_complement_nonweak(aut);
-      }
-    else
-      {
-	// Simply complete the automaton, and complement its
-	// acceptance.
-	auto res = cleanup_acceptance_here(complete(aut));
-	res->set_acceptance(res->num_sets(),
-			    res->get_acceptance().complement());
-	return res;
-      }
-  }
-}

src/twaalgos/minimize.cc

@@ -44,7 +44,8 @@
 #include "twaalgos/ltl2tgba_fm.hh"
 #include "twaalgos/bfssteps.hh"
 #include "twaalgos/isdet.hh"
-#include "twaalgos/dtgbacomp.hh"
+#include "twaalgos/complement.hh"
+#include "twaalgos/remfin.hh"
 
 namespace spot
 {
@@ -632,7 +633,7 @@ namespace spot
 	  {
 	    // If the automaton is deterministic, complementing is
 	    // easy.
-	    aut_neg_f = dtgba_complement(aut_f);
+	    aut_neg_f = remove_fin(dtwa_complement(aut_f));
 	  }
 	else
 	  {
@@ -654,7 +655,7 @@ namespace spot
       {
 	// Complement the minimized WDBA.
 	assert(min_aut_f->is_inherently_weak());
-	auto neg_min_aut_f = dtgba_complement(min_aut_f);
+	auto neg_min_aut_f = remove_fin(dtwa_complement(min_aut_f));
 	if (product(aut_f, neg_min_aut_f)->is_empty())
 	  // Finally, we are now sure that it was safe
 	  // to minimize the automaton.

src/twaalgos/postproc.cc

@@ -139,6 +139,23 @@ namespace spot
     return do_sba_simul(d, ba_simul_);
   }
 
+  twa_graph_ptr
+  postprocessor::do_scc_filter(const twa_graph_ptr& a, bool arg)
+  {
+    if (scc_filter_ == 0)
+      return a;
+    if (state_based_ && a->has_state_based_acc())
+      return scc_filter_states(a);
+    else
+      return scc_filter(a, arg);
+  }
+
+  twa_graph_ptr
+  postprocessor::do_scc_filter(const twa_graph_ptr& a)
+  {
+    return do_scc_filter(a, scc_filter_ > 1);
+  }
+
 #define PREF_ (pref_ & (Small | Deterministic))
 #define COMP_ (pref_ & Complete)
 #define SBACC_ (pref_ & SBAcc)
@@ -146,22 +163,6 @@ namespace spot
   twa_graph_ptr
   postprocessor::run(twa_graph_ptr a, formula f)
   {
-    if (type_ != Generic && !a->acc().is_generalized_buchi())
-      a = to_generalized_buchi(a);
-
-    if (PREF_ == Any && level_ == Low)
-      if (type_ == Generic
-	  || type_ == TGBA
-	  || (type_ == BA && a->is_sba())
-	  || (type_ == Monitor && a->num_sets() == 0))
-	{
-	  if (COMP_)
-	    a = complete(a);
-	  if (SBACC_)
-	    a = sbacc(a);
-	  return a;
-	}
-
     if (simul_ < 0)
       simul_ = (level_ == Low) ? 1 : 3;
     if (ba_simul_ < 0)
@@ -171,6 +172,28 @@ namespace spot
     if (type_ == BA || SBACC_)
       state_based_ = true;
 
+    bool tgb_used = false;
+    if (type_ != Generic && !a->acc().is_generalized_buchi())
+      {
+	a = to_generalized_buchi(a);
+	tgb_used = true;
+      }
+
+    if (PREF_ == Any && level_ == Low)
+      if (type_ == Generic
+	  || type_ == TGBA
+	  || (type_ == BA && a->is_sba())
+	  || (type_ == Monitor && a->num_sets() == 0))
+	{
+	  if (tgb_used)
+	    a = do_scc_filter(a);
+	  if (COMP_)
+	    a = complete(a);
+	  if (SBACC_)
+	    a = sbacc(a);
+	  return a;
+	}
+
     int original_acc = a->num_sets();
 
     // Remove useless SCCs.
@@ -178,13 +201,8 @@ namespace spot
       // Do not bother about acceptance conditions, they will be
       // ignored.
       a = scc_filter_states(a);
-    else if (scc_filter_ > 0)
+    else
-      {
+      a = do_scc_filter(a);
-	if (state_based_ && a->has_state_based_acc())
-	  a = scc_filter_states(a);
-	else
-	  a = scc_filter(a, scc_filter_ > 1);
-      }
 
     if (type_ == Monitor)
       {
@@ -380,7 +398,7 @@ namespace spot
 	    in = dba;
 	  }
 
-	const_twa_graph_ptr res = complete(in);
+	twa_graph_ptr res = complete(in);
 	if (target_acc == 1)
 	  {
 	    if (sat_states_ != -1)
@@ -408,14 +426,7 @@ namespace spot
 
 	if (res)
 	  {
-	    if (state_based_)
+	    dba = do_scc_filter(res, true);
-	      // FIXME: This does not simplify generalized acceptance
-	      // conditions, but calling scc_filter() would break the
-	      // BA-typeness of res by removing acceptance marks from
-	      // out-of-SCC transitions.
-	      dba = scc_filter_states(res);
-	    else
-	      dba = scc_filter(res, true);
 	    dba_is_minimal = true;
 	  }
       }
@@ -438,18 +449,12 @@ namespace spot
       {
 	if (dba && !dba_is_minimal) // WDBA is already clean.
 	  {
-	    if (state_based_ && dba->has_state_based_acc())
+	    dba = do_scc_filter(dba, true);
-	      dba = scc_filter_states(dba);
-	    else
-	      dba = scc_filter(dba, true);
 	    assert(!sim);
 	  }
 	else if (sim)
 	  {
-	    if (state_based_ && sim->has_state_based_acc())
+	    sim = do_scc_filter(sim, true);
-	      sim = scc_filter_states(sim);
-	    else
-	      sim = scc_filter(sim, true);
 	    assert(!dba);
 	  }
       }

src/twaalgos/postproc.hh

@@ -105,6 +105,8 @@ namespace spot
     twa_graph_ptr do_simul(const twa_graph_ptr& input, int opt);
     twa_graph_ptr do_sba_simul(const twa_graph_ptr& input, int opt);
     twa_graph_ptr do_degen(const twa_graph_ptr& input);
+    twa_graph_ptr do_scc_filter(const twa_graph_ptr& a, bool arg);
+    twa_graph_ptr do_scc_filter(const twa_graph_ptr& a);
 
     output_type type_;
     int pref_;

src/twaalgos/powerset.cc

@@ -34,7 +34,8 @@
 #include "twaalgos/gtec/gtec.hh"
 #include "twaalgos/sccfilter.hh"
 #include "twaalgos/ltl2tgba_fm.hh"
-#include "twaalgos/dtgbacomp.hh"
+#include "twaalgos/complement.hh"
+#include "twaalgos/remfin.hh"
 #include "misc/bitvect.hh"
 #include "misc/bddlt.hh"
 
@@ -426,7 +427,7 @@ namespace spot
 
     if (product(det, neg_aut)->is_empty())
       // Complement the DBA.
-      if (product(aut, dtgba_complement(det))->is_empty())
+      if (product(aut, remove_fin(dtwa_complement(det)))->is_empty())
 	// Finally, we are now sure that it was safe
 	// to determinize the automaton.
 	return det;

src/twaalgos/remfin.cc

@@ -22,6 +22,7 @@
 #include <iostream>
 #include "cleanacc.hh"
 #include "totgba.hh"
+#include "isdet.hh"
 #include "mask.hh"
 
 //#define TRACE
@@ -450,6 +451,54 @@ namespace spot
       return res;
     }
 
+    static twa_graph_ptr
+    remove_fin_det_weak(const const_twa_graph_ptr& aut)
+    {
+      // Clone the original automaton.
+      auto res = make_twa_graph(aut,
+				{
+				  true, // state based
+				    true, // inherently weak
+				    true, // determinisitic
+				    true,  // stutter inv.
+				    });
+      scc_info si(res);
+
+      // We will modify res in place, and the resulting
+      // automaton will only have one acceptance set.
+      acc_cond::mark_t all_acc = res->set_buchi();
+      res->prop_state_based_acc();
+      res->prop_deterministic();
+
+      unsigned sink = res->num_states();
+      for (unsigned src = 0; src < sink; ++src)
+	{
+	  acc_cond::mark_t acc = 0U;
+	  unsigned scc = si.scc_of(src);
+	  if (si.is_accepting_scc(scc) && !si.is_trivial(scc))
+	    acc = all_acc;
+	  // Keep track of all conditions on edge leaving state
+	  // SRC, so we can complete it.
+	  bdd missingcond = bddtrue;
+	  for (auto& t: res->out(src))
+	    {
+	      missingcond -= t.cond;
+	      t.acc = acc;
+	    }
+	  // Complete the original automaton.
+	  if (missingcond != bddfalse)
+	    {
+	      if (res->num_states() == sink)
+		{
+		  res->new_state();
+		  res->new_acc_edge(sink, sink, bddtrue);
+		}
+	      res->new_edge(src, sink, missingcond);
+	    }
+	}
+      //res->merge_edges();
+      return res;
+    }
   }
 
   twa_graph_ptr remove_fin(const const_twa_graph_ptr& aut)
@@ -457,6 +506,10 @@ namespace spot
     if (!aut->acc().uses_fin_acceptance())
       return std::const_pointer_cast<twa_graph>(aut);
 
+    // FIXME: we should check whether the automaton is weak.
+    if (aut->is_inherently_weak() && is_deterministic(aut))
+      return remove_fin_det_weak(aut);
+
     if (auto maybe = streett_to_generalized_buchi_maybe(aut))
       return maybe;
 
@@ -609,13 +662,13 @@ namespace spot
     unsigned nst = aut->num_states();
     auto res = make_twa_graph(aut->get_dict());
     res->copy_ap_of(aut);
-    res->prop_copy(aut, { false, false, false, true });
+    res->prop_copy(aut, { true, false, false, true });
     res->new_states(nst);
     res->set_acceptance(aut->num_sets() + extra_sets, new_code);
     res->set_init_state(aut->get_init_state_number());
 
+    bool sbacc = aut->has_state_based_acc();
     scc_info si(aut);
-
     unsigned nscc = si.scc_count();
     std::vector<unsigned> state_map(nst);
     for (unsigned n = 0; n < nscc; ++n)
@@ -643,7 +696,12 @@ namespace spot
 	// Create the main copy
 	for (auto s: states)
 	  for (auto& t: aut->out(s))
-	    res->new_edge(s, t.dst, t.cond, (t.acc & main_sets) | main_add);
+	    {
+	      acc_cond::mark_t a = 0U;
+	      if (sbacc || SPOT_LIKELY(si.scc_of(t.dst) == n))
+		a = (t.acc & main_sets) | main_add;
+	      res->new_edge(s, t.dst, t.cond, a);
+	    }
 
 	// We do not need any other copy if the SCC is non-accepting,
 	// of if it does not intersect any Fin.
@@ -673,22 +731,27 @@ namespace spot
 		      // We need only one non-deterministic jump per
 		      // cycle.  As an approximation, we only do
 		      // them on back-links.
-		      //
-		      // The acceptance marks on these edge
-		      // are useless, but we keep them to preserve
-		      // state-based acceptance if any.
 		      if (t.dst <= s)
-			res->new_edge(s, nd, t.cond,
+			{
-				      (t.acc & main_sets) | main_add);
+			  acc_cond::mark_t a = 0U;
+			  if (sbacc)
+			    a = (t.acc & main_sets) | main_add;
+			  res->new_edge(s, nd, t.cond, a);
+			}
 		    }
 		}
 	    }
       }
 
+    // If the input had no Inf, the output is a state-based automaton.
+    if (allinf == 0U)
+      res->prop_state_based_acc();
+
     res->purge_dead_states();
     trace << "before cleanup: " << res->get_acceptance() << '\n';
     cleanup_acceptance_here(res);
     trace << "after cleanup: " << res->get_acceptance() << '\n';
+    res->merge_edges();
     return res;
   }
 }

src/twaalgos/stutter.cc

@@ -27,7 +27,8 @@
 #include "twaalgos/product.hh"
 #include "twaalgos/ltl2tgba_fm.hh"
 #include "twaalgos/isdet.hh"
-#include "twaalgos/dtgbacomp.hh"
+#include "twaalgos/complement.hh"
+#include "twaalgos/remfin.hh"
 #include "twa/twaproduct.hh"
 #include "twa/bddprint.hh"
 #include <deque>
@@ -635,8 +636,7 @@ namespace spot
 	aut->prop_deterministic(is_deterministic(aut));
 	if (!aut->is_deterministic())
 	  return false;
-
+	neg = remove_fin(dtwa_complement(aut));
-	neg = dtgba_complement(aut);
       }
 
     is_stut = is_stutter_invariant(make_twa_graph(aut, twa::prop_set::all()),

wrap/python/spot_impl.i

@@ -113,6 +113,7 @@
 #include "twaalgos/degen.hh"
 #include "twaalgos/copy.hh"
 #include "twaalgos/complete.hh"
+#include "twaalgos/complement.hh"
 #include "twaalgos/emptiness.hh"
 #include "twaalgos/gtec/gtec.hh"
 #include "twaalgos/lbtt.hh"
@@ -266,6 +267,7 @@ namespace std {
 %include "twaalgos/dot.hh"
 %include "twaalgos/copy.hh"
 %include "twaalgos/complete.hh"
+%include "twaalgos/complement.hh"
 %include "twaalgos/emptiness.hh"
 %include "twaalgos/gtec/gtec.hh"
 %include "twaalgos/lbtt.hh"