postproc: introduce --parity output

* spot/twaalgos/postproc.hh, spot/twaalgos/postproc.cc: Add parity
  options.
* bin/common_post.cc: Add support for --parity.
* NEWS: Mention it.
* tests/core/parity2.test: New file.
* tests/Makefile.am: Add it.

NEWS

@@ -47,6 +47,11 @@ New in spot 2.4.4.dev (net yet released)
   - ltlsynt is a new tool for synthesizing a controller from LTL/PSL
     specifications.
 
+  - ltl2tgba, autfilt, and dstar2tgba have a new '--parity' option to
+    force parity acceptance on the output.  Different styles can be
+    requested using for instance --parity='min odd' or --parity='max
+    even'.
+
   - ltldo learned to limit the number of automata it outputs using -n.
 
   - autcross, ltlcross, and ltldo learned --fail-on-timeout.
@@ -176,6 +181,11 @@ New in spot 2.4.4.dev (net yet released)
     optimization for stutter-invariant automata that may produce slightly
     smaller automata.
 
+  - spot::postprocessor::set_type() can now request different forms of
+    parity acceptance as output.  However currently the conversions
+    are not very smart: if the input does not already have parity
+    acceptance, it will simply be degeneralized or determinized.
+
   - acc_cond::name(fmt) is a new method that name well-known acceptance
     conditions.   The fmt parameter specify the format to use for that
     name (e.g. to the style used in HOA, or that used by print_dot()).

bin/common_post.cc

 // -*- coding: utf-8 -*-
-// Copyright (C) 2012, 2013, 2014, 2015, 2016 Laboratoire de Recherche
-// et Développement de l'Epita (LRDE).
+// Copyright (C) 2012-2016, 2018 Laboratoire de Recherche et
+// Développement de l'Epita (LRDE).
 //
 // This file is part of Spot, a model checking library.
 //
@@ -21,6 +21,7 @@
 #include "common_r.hh"
 #include "common_aoutput.hh"
 #include "error.h"
+#include "argmatch.h"
 
 spot::postprocessor::output_type type = spot::postprocessor::TGBA;
 spot::postprocessor::output_pref pref = spot::postprocessor::Small;
@@ -55,6 +56,10 @@ static constexpr const argp_option options[] =
     { "state-based-acceptance", 'S', nullptr, 0,
       "define the acceptance using states", 0 },
     { "sbacc", 0, nullptr, OPTION_ALIAS, nullptr, 0 },
+    { "parity", 'P',
+      "any|min|max|odd|even|min odd|min even|max odd|max even",
+      OPTION_ARG_OPTIONAL,
+      "automaton with parity acceptance", 0, },
     /**************************************************/
     { nullptr, 0, nullptr, 0, "Simplification goal:", 20 },
     { "small", OPT_SMALL, nullptr, 0, "prefer small automata (default)", 0 },
@@ -105,6 +110,10 @@ static const argp_option options_disabled[] =
     { "state-based-acceptance", 'S', nullptr, 0,
       "define the acceptance using states", 0 },
     { "sbacc", 0, nullptr, OPTION_ALIAS, nullptr, 0 },
+    { "parity", 'P',
+      "[any|min|max|odd|even|min odd|min even|max odd|max even]",
+      OPTION_ARG_OPTIONAL,
+      "automaton with parity acceptance", 0, },
     /**************************************************/
     { nullptr, 0, nullptr, 0, "Simplification goal:", 20 },
     { "small", OPT_SMALL, nullptr, 0, "prefer small automata", 0 },
@@ -123,7 +132,7 @@ static const argp_option options_disabled[] =
   };
 
 static int
-parse_opt_post(int key, char*, struct argp_state*)
+parse_opt_post(int key, char* arg, struct argp_state*)
 {
   // This switch is alphabetically-ordered.
   switch (key)
@@ -148,6 +157,40 @@ parse_opt_post(int key, char*, struct argp_state*)
     case 'M':
       type = spot::postprocessor::Monitor;
       break;
+    case 'P':
+      {
+        static char const *const parity_args[] =
+          {
+            "any", "min", "max", "odd", "even",
+            "min odd", "odd min",
+            "min even", "even min",
+            "max odd", "odd max",
+            "max even", "even max",
+            nullptr
+          };
+        static spot::postprocessor::output_type const parity_types[] =
+          {
+            spot::postprocessor::Parity,
+            spot::postprocessor::ParityMin,
+            spot::postprocessor::ParityMax,
+            spot::postprocessor::ParityOdd,
+            spot::postprocessor::ParityEven,
+            spot::postprocessor::ParityMinOdd,
+            spot::postprocessor::ParityMinOdd,
+            spot::postprocessor::ParityMinEven,
+            spot::postprocessor::ParityMinEven,
+            spot::postprocessor::ParityMaxOdd,
+            spot::postprocessor::ParityMaxOdd,
+            spot::postprocessor::ParityMaxEven,
+            spot::postprocessor::ParityMaxEven,
+          };
+        ARGMATCH_VERIFY(parity_args, parity_types);
+        if (arg)
+          type = XARGMATCH("--parity", arg, parity_args, parity_types);
+        else
+          type = spot::postprocessor::Parity;
+      }
+      break;
     case 'S':
       sbacc = spot::postprocessor::SBAcc;
       break;

spot/twaalgos/postproc.cc

 // -*- coding: utf-8 -*-
-// Copyright (C) 2012-2017 Laboratoire de Recherche et Développement
+// Copyright (C) 2012-2018 Laboratoire de Recherche et Développement
 // de l'Epita (LRDE).
 //
 // This file is part of Spot, a model checking library.
@@ -35,6 +35,7 @@
 #include <spot/twaalgos/sepsets.hh>
 #include <spot/twaalgos/determinize.hh>
 #include <spot/twaalgos/alternation.hh>
+#include <spot/twaalgos/parity.hh>
 
 namespace spot
 {
@@ -147,6 +148,15 @@ namespace spot
     return do_sba_simul(d, ba_simul_);
   }
 
+  twa_graph_ptr
+  postprocessor::do_degen_tba(const twa_graph_ptr& a)
+  {
+    return degeneralize_tba(a,
+                            degen_reset_, degen_order_,
+                            degen_cache_, degen_lskip_,
+                            degen_lowinit_, degen_remscc_);
+  }
+
   twa_graph_ptr
   postprocessor::do_scc_filter(const twa_graph_ptr& a, bool arg)
   {
@@ -183,6 +193,33 @@ namespace spot
     if (type_ == BA || SBACC_)
       state_based_ = true;
 
+    bool want_parity = (type_ & Parity) == Parity;
+
+    auto finalize = [&](twa_graph_ptr tmp)
+      {
+        if (COMP_)
+          tmp = complete(tmp);
+        if (want_parity && tmp->acc().is_generalized_buchi())
+          tmp = SBACC_ ? do_degen(tmp) : do_degen_tba(tmp);
+        if (SBACC_)
+          tmp = sbacc(tmp);
+        if (want_parity)
+          {
+            parity_kind kind = parity_kind_any;
+            parity_style style = parity_style_any;
+            if ((type_ & ParityMin) == ParityMin)
+              kind = parity_kind_min;
+            else if ((type_ & ParityMax) == ParityMax)
+              kind = parity_kind_max;
+            if ((type_ & ParityOdd) == ParityOdd)
+              style = parity_style_odd;
+            else if ((type_ & ParityEven) == ParityEven)
+              style = parity_style_even;
+            change_parity_here(tmp, kind, style);
+          }
+        return tmp;
+      };
+
     if (!a->is_existential() &&
         // We will probably have to revisit this condition later.
         // Currently, the intent is that postprocessor should never
@@ -191,7 +228,8 @@ namespace spot
         !(type_ == Generic && PREF_ == Any && level_ == Low))
       a = remove_alternation(a);
 
-    if (type_ != Generic && !a->acc().is_generalized_buchi())
+    if ((type_ != Generic && !a->acc().is_generalized_buchi())
+        || (want_parity && !a->acc().is_parity()))
       {
         a = to_generalized_buchi(a);
         if (PREF_ == Any && level_ == Low)
@@ -202,14 +240,9 @@ namespace spot
         && (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;
-      }
+            || (type_ == Monitor && a->num_sets() == 0)
+            || (want_parity && a->acc().is_parity())))
+      return finalize(a);
 
     int original_acc = a->num_sets();
 
@@ -244,20 +277,14 @@ namespace spot
               }
             a->remove_unused_ap();
           }
-        if (COMP_)
-          a = complete(a);
-        return a;
+        return finalize(a);
       }
 
     if (PREF_ == Any)
       {
         if (type_ == BA)
           a = do_degen(a);
-        if (COMP_)
-          a = complete(a);
-        if (SBACC_)
-          a = sbacc(a);
-        return a;
+        return finalize(a);
       }
 
     bool dba_is_wdba = false;
@@ -305,6 +332,8 @@ namespace spot
             // No need to do that if tba_determinisation_ will be used.
             if (type_ == BA && !tba_determinisation_)
               sim = do_degen(sim);
+            else if (want_parity && !sim->acc().is_parity())
+              sim = do_degen_tba(sim);
             else if (SBACC_ && !tba_determinisation_)
               sim = sbacc(sim);
           }
@@ -382,7 +411,7 @@ namespace spot
           }
       }
 
-    if (PREF_ == Deterministic && type_ == Generic && !dba)
+    if ((PREF_ == Deterministic && (type_ == Generic || want_parity)) && !dba)
       {
         dba = tgba_determinize(to_generalized_buchi(sim),
                                false, det_scc_, det_simul_, det_stutter_);
@@ -517,12 +546,6 @@ namespace spot
     sim = dba ? dba : sim;
 
     sim->remove_unused_ap();
-
-    if (COMP_)
-      sim = complete(sim);
-    if (SBACC_)
-      sim = sbacc(sim);
-
-    return sim;
+    return finalize(sim);
   }
 }

spot/twaalgos/postproc.hh

 // -*- coding: utf-8 -*-
-// Copyright (C) 2012-2017 Laboratoire de Recherche et Développement
+// Copyright (C) 2012-2018 Laboratoire de Recherche et Développement
 // de l'Epita (LRDE).
 //
 // This file is part of Spot, a model checking library.
@@ -72,7 +72,20 @@ namespace spot
     /// options used for debugging or benchmarking.
     postprocessor(const option_map* opt = nullptr);
 
-    enum output_type { TGBA, BA, Monitor, Generic };
+    enum output_type { TGBA = 0,
+                       BA = 1,
+                       Monitor = 2,
+                       Generic = 3,
+                       Parity = 4,
+                       ParityMin = Parity | 8,
+                       ParityMax = Parity | 16,
+                       ParityOdd = Parity | 32,
+                       ParityEven = Parity | 64,
+                       ParityMinOdd = ParityMin | ParityOdd,
+                       ParityMaxOdd = ParityMax | ParityOdd,
+                       ParityMinEven = ParityMin | ParityEven,
+                       ParityMaxEven = ParityMax | ParityEven,
+    };
 
     /// \brief Select the desired output type.
     ///
@@ -96,11 +109,17 @@ namespace spot
     /// SystemC" (Deian Tabakov and Moshe Y. Vardi, Proceedings of
     /// RV’10, LNCS 6418).
     ///
-    /// Finally \c Generic remove all constraints about the acceptance
-    /// condition.  Using \c Generic can be needed to force the
-    /// determinization of some automata (e.g., not all TGBA can be
-    /// degeneralized, using \c Generic will allow parity acceptance
-    /// to be used instead).
+    /// \c Generic removes all constraints about the acceptance
+    /// condition.  Using \c Generic (or \c Parity below) can be
+    /// needed to force the determinization of some automata (e.g.,
+    /// not all TGBA can be degeneralized, using \c Generic will allow
+    /// parity acceptance to be used instead).
+    ///
+    /// \a Parity and its variants request the acceptance condition to
+    /// be of some parity type.  Note that the determinization
+    /// algorithm used by Spot produces "parity min odd" acceptance,
+    /// but other parity types can be obtained from there by minor
+    /// adjustments.
     ///
     /// If set_type() is not called, the default \c output_type is \c TGBA.
     void
@@ -195,6 +214,7 @@ 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_degen_tba(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);
 

tests/Makefile.am

 ## -*- coding: utf-8 -*-
 
-## Copyright (C) 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017
-## Laboratoire de Recherche et Développement de l'Epita (LRDE).
-## Copyright (C) 2003, 2004, 2005, 2006 Laboratoire d'Informatique de
-## Paris 6 (LIP6), département Systèmes Répartis Coopératifs (SRC),
-## Université Pierre et Marie Curie.
+## Copyright (C) 2009-2018 Laboratoire de Recherche et Développement
+## de l'Epita (LRDE).
+## Copyright (C) 2003-2006 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.
 ##
@@ -310,6 +310,7 @@ TESTS_twa = \
   core/dca.test \
   core/dnfstreett.test \
   core/parity.test \
+  core/parity2.test \
   core/ltlsynt.test
 
 ############################## PYTHON ##############################

tests/core/parity2.test

+#!/bin/sh
+# -*- coding: utf-8 -*-
+# Copyright (C) 2018 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/>.
+
+. ./defs
+set -e
+
+rm -rf res res2
+
+for x in P 'Pmin odd' 'Pmax even'; do
+  ltl2tgba "-$x" FGa 'GFa & GFb' >>res
+  ltl2tgba FGa 'GFa & GFb' | autfilt --name=%M --high "-$x" >>res2
+  ltl2tgba -D "-$x" FGa 'GFa & GFb' >>res3
+  ltl2tgba FGa 'GFa & GFb' | autfilt -D --name=%M --high "-$x" >>res4
+done
+
+cat >expected<<EOF
+HOA: v1
+name: "FGa"
+States: 2
+Start: 0
+AP: 1 "a"
+acc-name: Buchi
+Acceptance: 1 Inf(0)
+properties: trans-labels explicit-labels state-acc stutter-invariant
+properties: inherently-weak
+--BODY--
+State: 0
+[t] 0
+[0] 1
+State: 1 {0}
+[0] 1
+--END--
+HOA: v1
+name: "G(Fa & Fb)"
+States: 2
+Start: 0
+AP: 2 "a" "b"
+acc-name: Buchi
+Acceptance: 1 Inf(0)
+properties: trans-labels explicit-labels trans-acc complete
+properties: deterministic stutter-invariant
+--BODY--
+State: 0
+[0&1] 0 {0}
+[!1] 0
+[!0&1] 1
+State: 1
+[0] 0 {0}
+[!0] 1
+--END--
+HOA: v1
+name: "FGa"
+States: 2
+Start: 0
+AP: 1 "a"
+acc-name: Rabin 1
+Acceptance: 2 Fin(0) & Inf(1)
+properties: trans-labels explicit-labels state-acc stutter-invariant
+properties: inherently-weak
+--BODY--
+State: 0
+[t] 0
+[0] 1
+State: 1 {1}
+[0] 1
+--END--
+HOA: v1
+name: "G(Fa & Fb)"
+States: 2
+Start: 0
+AP: 2 "a" "b"
+acc-name: Rabin 1
+Acceptance: 2 Fin(0) & Inf(1)
+properties: trans-labels explicit-labels trans-acc complete
+properties: deterministic stutter-invariant
+--BODY--
+State: 0
+[0&1] 0 {1}
+[!1] 0
+[!0&1] 1
+State: 1
+[0] 0 {1}
+[!0] 1
+--END--
+HOA: v1
+name: "FGa"
+States: 2
+Start: 0
+AP: 1 "a"
+acc-name: Buchi
+Acceptance: 1 Inf(0)
+properties: trans-labels explicit-labels state-acc stutter-invariant
+properties: inherently-weak
+--BODY--
+State: 0
+[t] 0
+[0] 1
+State: 1 {0}
+[0] 1
+--END--
+HOA: v1
+name: "G(Fa & Fb)"
+States: 2
+Start: 0
+AP: 2 "a" "b"
+acc-name: Buchi
+Acceptance: 1 Inf(0)
+properties: trans-labels explicit-labels trans-acc complete
+properties: deterministic stutter-invariant
+--BODY--
+State: 0
+[0&1] 0 {0}
+[!1] 0
+[!0&1] 1
+State: 1
+[0] 0 {0}
+[!0] 1
+--END--
+EOF
+
+diff expected res
+diff expected res2
+
+cat >expected2<<EOF
+HOA: v1
+name: "FGa"
+States: 2
+Start: 0
+AP: 1 "a"
+acc-name: Rabin 1
+Acceptance: 2 Fin(0) & Inf(1)
+properties: trans-labels explicit-labels trans-acc complete
+properties: deterministic stutter-invariant
+--BODY--
+State: 0
+[!0] 0
+[0] 1 {1}
+State: 1
+[!0] 0 {0}
+[0] 1 {1}
+--END--
+HOA: v1
+name: "G(Fa & Fb)"
+States: 2
+Start: 0
+AP: 2 "a" "b"
+acc-name: Buchi
+Acceptance: 1 Inf(0)
+properties: trans-labels explicit-labels trans-acc complete
+properties: deterministic stutter-invariant
+--BODY--
+State: 0
+[0&1] 0 {0}
+[!1] 0
+[!0&1] 1
+State: 1
+[0] 0 {0}
+[!0] 1
+--END--
+HOA: v1
+name: "FGa"
+States: 2
+Start: 0
+AP: 1 "a"
+acc-name: Rabin 1
+Acceptance: 2 Fin(0) & Inf(1)
+properties: trans-labels explicit-labels trans-acc complete
+properties: deterministic stutter-invariant
+--BODY--
+State: 0
+[!0] 0
+[0] 1 {1}
+State: 1
+[!0] 0 {0}
+[0] 1 {1}
+--END--
+HOA: v1
+name: "G(Fa & Fb)"
+States: 2
+Start: 0
+AP: 2 "a" "b"
+acc-name: Rabin 1
+Acceptance: 2 Fin(0) & Inf(1)
+properties: trans-labels explicit-labels trans-acc complete
+properties: deterministic stutter-invariant
+--BODY--
+State: 0
+[0&1] 0 {1}
+[!1] 0
+[!0&1] 1
+State: 1
+[0] 0 {1}
+[!0] 1
+--END--
+HOA: v1
+name: "FGa"
+States: 2
+Start: 0
+AP: 1 "a"
+acc-name: parity max even 2
+Acceptance: 2 Fin(1) & Inf(0)
+properties: trans-labels explicit-labels trans-acc complete
+properties: deterministic stutter-invariant
+--BODY--
+State: 0
+[!0] 0
+[0] 1 {0}
+State: 1
+[!0] 0 {1}
+[0] 1 {0}
+--END--
+HOA: v1
+name: "G(Fa & Fb)"
+States: 2
+Start: 0
+AP: 2 "a" "b"
+acc-name: Buchi
+Acceptance: 1 Inf(0)
+properties: trans-labels explicit-labels trans-acc complete
+properties: deterministic stutter-invariant
+--BODY--
+State: 0
+[0&1] 0 {0}
+[!1] 0
+[!0&1] 1
+State: 1
+[0] 0 {0}
+[!0] 1
+--END--
+EOF
+diff expected2 res3
+diff expected2 res4
+
+ltlcross 'ltl2tgba -P' 'ltl2tgba -P"odd max"' 'ltl2tgba -P"even min"' \
+         -f FGa -f 'GFa&GFb' -f 'GF(a <-> XXXb)'