parity: add spot::change_parity()

This function changes the parity acceptance of an automaton.

* spot/twaalgos/parity.cc, spot/twaalgos/parity.hh: Here
* python/spot/impl.i: Add spot/twaalgos/parity.hh
* spot/twaalgos/Makefile.am: Add spot/twaalgos/parity.{cc,hh}
* tests/core/parity.cc, tests/core/parity.test: Add
spot::change_parity() tests
* tests/python/parity.ipynb: Add documentation about
spot::change_parity()
* tests/Makefile.am: Add tests/core/parity.{cc,hh} and
tests/python/parity.ipynb
* doc/org/tut.org: Add the html page of tests/python/parity.ipynb

doc/org/tut.org

@@ -66,6 +66,8 @@ real notebooks instead.
 - [[https://spot.lrde.epita.fr/ipynb/accparse.html][=accparse.ipynb=]] exercises the acceptance condition parser
 - [[https://spot.lrde.epita.fr/ipynb/acc_cond.html][=acc_cond.ipynb=]] documents the interface for manipulating acceptance
   conditions
+- [[https://spot.lrde.epita.fr/ipynb/parity.html][=parity.ipynb=]] documents algorithms for manipulating parity automata
+  in Python
 - [[https://spot.lrde.epita.fr/ipynb/product.html][=product.ipynb=]] shows how to re-implement the product of two automata
   in Python
 - [[https://spot.lrde.epita.fr/ipynb/randltl.html][=randltl.ipynb=]] demonstrates a Python-version of [[file:randltl.org][=randltl=]]

python/spot/impl.i

@@ -151,6 +151,7 @@
 #include <spot/twaalgos/simulation.hh>
 #include <spot/twaalgos/split.hh>
 #include <spot/twaalgos/sum.hh>
+#include <spot/twaalgos/parity.hh>
 #include <spot/twaalgos/postproc.hh>
 #include <spot/twaalgos/product.hh>
 #include <spot/twaalgos/stutter.hh>
@@ -582,6 +583,7 @@ def state_is_accepting(self, src) -> "bool":
 %include <spot/twaalgos/isunamb.hh>
 %include <spot/twaalgos/isweakscc.hh>
 %include <spot/twaalgos/simulation.hh>
+%include <spot/twaalgos/parity.hh>
 %include <spot/twaalgos/postproc.hh>
 %include <spot/twaalgos/product.hh>
 %include <spot/twaalgos/split.hh>

spot/twaalgos/Makefile.am

@@ -62,6 +62,7 @@ twaalgos_HEADERS = \
   minimize.hh \
   couvreurnew.hh \
   neverclaim.hh \
+  parity.hh \
   postproc.hh \
   powerset.hh \
   product.hh \
@@ -125,6 +126,7 @@ libtwaalgos_la_SOURCES = \
   couvreurnew.cc \
   ndfs_result.hxx \
   neverclaim.cc \
+  parity.cc \
   postproc.cc \
   powerset.cc \
   product.cc \

spot/twaalgos/parity.cc

+// -*- coding: utf-8 -*-
+// Copyright (C) 2016 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/>.
+
+#include <spot/twaalgos/parity.hh>
+#include <spot/twa/twagraph.hh>
+#include <spot/twaalgos/product.hh>
+#include <vector>
+#include <utility>
+#include <functional>
+#include <queue>
+#include <spot/twaalgos/hoa.hh>
+
+namespace spot
+{
+  namespace
+  {
+    unsigned change_set(unsigned x, unsigned num_sets,
+                        bool change_kind, bool change_style)
+    {
+      // If the parity acceptance kind is changed,
+      // then the index of the sets are reversed
+      if (change_kind)
+        x = num_sets - x - 1;
+      // If the parity style is changed, then all the existing acceptance
+      // sets are shifted
+      x += change_style;
+      return x;
+    }
+
+    void
+    change_acc(twa_graph_ptr& aut, unsigned num_sets, bool change_kind,
+               bool change_style, bool output_max, bool input_max)
+    {
+      for (auto& e: aut->edge_vector())
+        if (e.acc)
+          {
+            unsigned msb = (input_max ? e.acc.max_set() : e.acc.min_set()) - 1;
+            e.acc = acc_cond::mark_t{change_set(msb, num_sets, change_kind,
+                                                change_style)};
+          }
+        else if (output_max && change_style)
+          {
+            // If the parity is changed, a new set is introduced.
+            // This new set is used to mark all the transitions of the input
+            // that don't belong to any acceptance sets.
+            e.acc.set(0);
+          }
+    }
+  }
+
+  twa_graph_ptr
+  change_parity(const const_twa_graph_ptr& aut,
+                parity_kind kind, parity_style style)
+  {
+    return change_parity_here(make_twa_graph(aut, twa::prop_set::all()),
+                              kind, style);
+  }
+
+  twa_graph_ptr
+  change_parity_here(twa_graph_ptr aut, parity_kind kind, parity_style style)
+  {
+    bool current_max;
+    bool current_odd;
+    if (!aut->acc().is_parity(current_max, current_odd, true))
+      throw new std::invalid_argument("change_parity: input must have a parity "
+                                      "acceptance.");
+    auto old_num_sets = aut->num_sets();
+
+    bool output_max = true;
+    switch (kind)
+      {
+        case parity_kind_max:
+          output_max = true;
+          break;
+        case parity_kind_min:
+          output_max = false;
+          break;
+        case parity_kind_same:
+          output_max = current_max;
+          break;
+        case parity_kind_any:
+          // If we need to change the style we may change the kind not to
+          // introduce new accset.
+          output_max = (((style == parity_style_odd && !current_odd)
+                         || (style == parity_style_even && current_odd))
+                        && old_num_sets % 2 == 0) != current_max;
+          break;
+      }
+
+    bool change_kind = current_max != output_max;
+    bool toggle_style = change_kind && (old_num_sets % 2 == 0);
+
+    bool output_odd = true;
+    switch (style)
+      {
+        case parity_style_odd:
+          output_odd = true;
+          break;
+        case parity_style_even:
+          output_odd = false;
+          break;
+        case parity_style_same:
+          output_odd = current_odd;
+          break;
+        case parity_style_any:
+          output_odd = current_odd != toggle_style;
+          // If we need to change the kind we may change the style not to
+          // introduce new accset.
+          break;
+      }
+
+    current_odd = current_odd != toggle_style;
+    bool change_style = false;
+    auto num_sets = old_num_sets;
+    // If the parity neeeds to be changed, then a new acceptance set is created.
+    // The old acceptance sets are shifted
+    if (output_odd != current_odd)
+      {
+        change_style = true;
+        ++num_sets;
+      }
+
+    if (change_kind || change_style)
+      {
+        auto new_acc = acc_cond::acc_code::parity(output_max,
+                                                  output_odd, num_sets);
+        aut->set_acceptance(num_sets, new_acc);
+      }
+    change_acc(aut, old_num_sets, change_kind,
+               change_style, output_max, current_max);
+    return aut;
+  }
+}

spot/twaalgos/parity.hh

+// -*- coding: utf-8 -*-
+// Copyright (C) 2016 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/>.
+
+#pragma once
+
+#include <spot/misc/common.hh>
+#include <spot/twa/fwd.hh>
+
+namespace spot
+{
+  /// \addtogroup parity_algorithms Parity algorithms
+  /// \ingroup twa_algorithms
+  /// @{
+  /// \brief Parity kind type
+  enum parity_kind
+  {
+    /// The new acceptance will be a parity max
+    parity_kind_max,
+    /// The new acceptance will be a parity min
+    parity_kind_min,
+    /// The new acceptance will keep the kind
+    parity_kind_same,
+    /// The new acceptance may change the kind
+    parity_kind_any
+  };
+
+  /// \brief Parity  style type
+  enum parity_style
+  {
+    /// The new acceptance will be a parity odd
+    parity_style_odd,
+    /// The new acceptance will be a parity even
+    parity_style_even,
+    /// The new acceptance will keep the style
+    parity_style_same,
+    /// The new acceptance may change the style
+    parity_style_any
+  };
+
+  /// \brief Change the parity acceptance of an automaton
+  ///
+  /// The parity acceptance condition of an automaton is characterized by
+  ///    - The kind of the acceptance (min or max).
+  ///    - The parity style, i.e., parity of the sets seen infinitely often
+  ///      (odd or even).
+  ///    - The number of acceptance sets.
+  ///
+  /// The output will be an equivalent automaton with the new parity acceptance.
+  /// The number of acceptance sets may be increased by one. Every transition
+  /// will belong to at most one acceptance set. The automaton must have a
+  /// parity acceptance, otherwise an invalid_argument exception is thrown.
+  ///
+  /// The parity kind is defined only if the number of acceptance sets
+  /// is strictly greater than 1. The parity_style is defined only if the number
+  /// of acceptance sets is non-zero. Some values of kind and style may result
+  /// in equivalent outputs if the number of acceptance sets of the input
+  /// automaton is not great enough.
+  ///
+  /// \param aut the input automaton
+  ///
+  /// \param kind the parity kind of the output automaton
+  ///
+  /// \param style the parity style of the output automaton
+  ///
+  /// \return the automaton with the new acceptance
+  /// @{
+  SPOT_API twa_graph_ptr
+  change_parity(const const_twa_graph_ptr& aut,
+                parity_kind kind, parity_style style);
+
+  SPOT_API twa_graph_ptr
+  change_parity_here(twa_graph_ptr aut, parity_kind kind, parity_style style);
+  /// @}
+  /// @}
+}

tests/Makefile.am

@@ -82,6 +82,7 @@ check_PROGRAMS = \
   core/nequals \
   core/nenoform \
   core/ngraph \
+  core/parity \
   core/randtgba \
   core/readsat \
   core/reduc \
@@ -128,6 +129,7 @@ core_nenoform_SOURCES = core/equalsf.cc
 core_nenoform_CPPFLAGS = $(AM_CPPFLAGS) -DNENOFORM
 core_nequals_SOURCES = core/equalsf.cc
 core_nequals_CPPFLAGS = $(AM_CPPFLAGS) -DNEGATE
+core_parity_SOURCES = core/parity.cc
 core_reduc_SOURCES = core/reduc.cc
 core_reduccmp_SOURCES = core/equalsf.cc
 core_reduccmp_CPPFLAGS = $(AM_CPPFLAGS) -DREDUC
@@ -301,7 +303,8 @@ TESTS_twa = \
   core/cycles.test \
   core/acc_word.test \
   core/dca.test \
-  core/dnfstreett.test
+  core/dnfstreett.test \
+  core/parity.test
 
 ############################## PYTHON ##############################
 
@@ -324,6 +327,7 @@ TESTS_ipython = \
   python/ltsmin-dve.ipynb \
   python/ltsmin-pml.ipynb \
   python/piperead.ipynb \
+  python/parity.ipynb \
   python/product.ipynb \
   python/randaut.ipynb \
   python/randltl.ipynb \

tests/core/parity.cc

+// -*- coding: utf-8 -*-
+// Copyright (C) 2016 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/>.
+
+#include <cassert>
+#include <ctime>
+#include <vector>
+#include <spot/twaalgos/dualize.hh>
+#include <spot/twaalgos/hoa.hh>
+#include <spot/twaalgos/parity.hh>
+#include <spot/twaalgos/product.hh>
+#include <spot/twaalgos/randomgraph.hh>
+#include <spot/misc/random.hh>
+#include <spot/twa/twagraph.hh>
+#include <spot/twa/fwd.hh>
+#include <spot/twa/acc.hh>
+#include <spot/misc/trival.hh>
+#include <utility>
+#include <string>
+#include <iostream>
+
+#define LAST_AUT result.back().first
+#define LAST_NUM_SETS result.back().second
+#define NEW_AUT() do {                                                      \
+  result.emplace_back(spot::random_graph(6, 0.5, &apf,                      \
+                      current_bdd, 0, 0, 0.5, true), 0);                    \
+  LAST_NUM_SETS = 0;                                                        \
+  /* print_hoa need this */                                                 \
+  LAST_AUT->prop_state_acc(spot::trival::maybe());                          \
+} while (false)
+
+#define SET_TR(t, value) do {                                               \
+  unsigned value_tmp = value;                                               \
+  if (value_tmp + 1 > LAST_NUM_SETS)                                        \
+    LAST_NUM_SETS = value_tmp + 1;                                          \
+  t.acc.set(value_tmp);                                                     \
+} while (false)
+
+
+static std::vector<std::pair<spot::twa_graph_ptr, unsigned>>
+generate_aut(const spot::bdd_dict_ptr& current_bdd)
+{
+  spot::atomic_prop_set apf = spot::create_atomic_prop_set(3);
+  std::vector<std::pair<spot::twa_graph_ptr, unsigned>> result;
+  // No accset on any transition
+  NEW_AUT();
+  // The same accset on every transitions
+  NEW_AUT();
+  for (auto& t: LAST_AUT->edges())
+    SET_TR(t, 0);
+
+  // All used / First unused / Last unused / First and last unused
+  for (auto incr_ext: { 0, 1 })
+    for (auto used: { 1, 2 })
+      for (auto modulo: { 4, 5, 6 })
+        if (incr_ext + modulo <= 6)
+          {
+            NEW_AUT();
+            unsigned count = 0;
+            for (auto& t: LAST_AUT->edges())
+              if (std::rand() % used == 0)
+                {
+                  auto value = ++count % modulo + incr_ext;
+                  SET_TR(t, value);
+                }
+          }
+
+  // One-Three in middle not used
+  for (auto i: { 0, 1 })
+    for (auto start: { 1, 2 })
+      for (auto unused: { 1, 2, 3 })
+        {
+          NEW_AUT();
+          auto count = 0;
+          for (auto& t: LAST_AUT->edges())
+            {
+              int val = 0;
+              if (count % (3 + i) < start)
+                val = count % (3 + i);
+              else
+                val = count % (3 + i) + unused;
+              SET_TR(t, val);
+            }
+        }
+
+  // All accset on all transitions
+  for (auto i: { 0, 1 })
+  {
+    NEW_AUT();
+    for (auto& t: LAST_AUT->edges())
+      for (auto acc = 0; acc < 5 + i; ++acc)
+        SET_TR(t, acc);
+  }
+
+  // Some random automata
+  std::vector<std::vector<int>> cont_sets;
+  for (auto i = 0; i <= 6; ++i)
+    {
+      std::vector<int> cont_set;
+      for (auto j = 0; j < i; ++j)
+        cont_set.push_back(j);
+      cont_sets.push_back(cont_set);
+    }
+  for (auto min: { 0, 1 })
+    {
+      for (auto num_sets: { 1, 2, 5, 6 })
+        for (auto i = 0; i < 10; ++i)
+          {
+            NEW_AUT();
+            for (auto& t: LAST_AUT->edges())
+              {
+                auto nb_acc = std::rand() % (num_sets - min + 1) + min;
+                std::random_shuffle(cont_sets[num_sets].begin(),
+                                    cont_sets[num_sets].end());
+                for (auto j = 0; j < nb_acc; ++j)
+                  SET_TR(t, cont_sets[num_sets][j]);
+              }
+          }
+      for (auto num_sets: {2, 3})
+        for (auto even: {0, 1})
+          if ((num_sets - 1) * 2 + even < 6)
+            {
+              NEW_AUT();
+              for (auto& t: LAST_AUT->edges())
+                {
+                  auto nb_acc = std::rand() % (num_sets - min + 1) + min;
+                  std::random_shuffle(cont_sets[num_sets].begin(),
+                                      cont_sets[num_sets].end());
+                  for (auto j = 0; j < nb_acc; ++j)
+                    {
+                      auto value = cont_sets[num_sets][j] * 2 + even;
+                      SET_TR(t, value);
+                    }
+                }
+            }
+    }
+  return result;
+}
+
+static std::vector<std::tuple<spot::acc_cond::acc_code, bool, bool, unsigned>>
+generate_acc()
+{
+  std::vector<std::tuple<spot::acc_cond::acc_code, bool, bool, unsigned>>
+  result;
+  for (auto max: { true, false })
+    for (auto odd: { true, false })
+      for (auto num_sets: { 0, 1, 2, 5, 6 })
+        result.emplace_back(spot::acc_cond::acc_code::parity(max, odd,
+                            num_sets), max, odd, num_sets);
+  return result;
+}
+
+static bool is_included(spot::const_twa_graph_ptr left,
+                        spot::const_twa_graph_ptr right, bool first_left)
+{
+  auto tmp = spot::dualize(right);
+  auto product = spot::product(left, tmp);
+  if (!product->is_empty())
+    {
+      std::cerr << "======Not included======" << std::endl;
+      if (first_left)
+        std::cerr << "======First automaton======" << std::endl;
+      else
+        std::cerr << "======Second automaton======" << std::endl;
+      spot::print_hoa(std::cerr, left);
+      std::cerr << std::endl;
+      if (first_left)
+        std::cerr << "======Second automaton======" << std::endl;
+      else
+        std::cerr << "======First automaton======" << std::endl;
+      spot::print_hoa(std::cerr, right);
+      std::cerr << std::endl;
+      if (first_left)
+        std::cerr << "======!Second automaton======" << std::endl;
+      else
+        std::cerr << "======!First automaton======" << std::endl;
+      spot::print_hoa(std::cerr, tmp);
+      std::cerr << std::endl;
+      if (first_left)
+        std::cerr << "======First X !Second======" <<std::endl;
+      else
+        std::cerr << "======Second X !First======" <<std::endl;
+      spot::print_hoa(std::cerr, product);
+      std::cerr << std::endl;
+      return false;
+    }
+  return true;
+}
+
+static bool are_equiv(spot::const_twa_graph_ptr left,
+                      spot::const_twa_graph_ptr right)
+{
+  return is_included(left, right, true) && is_included(right, left, false);
+}
+
+static bool is_right_parity(spot::const_twa_graph_ptr aut,
+                            spot::parity_kind target_kind,
+                            spot::parity_style target_style,
+                            bool origin_max, bool origin_odd, unsigned num_sets)
+{
+  bool is_max;
+  bool is_odd;
+  if (!aut->acc().is_parity(is_max, is_odd))
+    return false;
+  bool target_max;
+  bool target_odd;
+  if (aut->num_sets() <= 1 || num_sets <= 1
+      || target_kind == spot::parity_kind_any)
+    target_max = is_max;
+  else if (target_kind == spot::parity_kind_max)
+    target_max = true;
+  else if (target_kind == spot::parity_kind_min)
+    target_max = false;
+  else
+    target_max = origin_max;
+  if (aut->num_sets() == 0 || num_sets == 0
+      || target_style == spot::parity_style_any)
+    target_odd = is_odd;
+  else if (target_style == spot::parity_style_odd)
+    target_odd = true;
+  else if (target_style == spot::parity_style_even)
+    target_odd = false;
+  else
+    target_odd = origin_odd;
+  if (!(is_max == target_max && is_odd == target_odd))
+    {
+      std::cerr << "======Wrong accceptance======" << std::endl;
+      std::string kind[] = { "max", "min", "same", "any" };
+      std::string style[] = { "odd", "even", "same", "any" };
+      std::cerr << "target: " << kind[target_kind] << ' '
+                << style[target_style] << std::endl;
+      std::cerr << "origin: " << kind[origin_max ? 0 : 1] << ' '
+                << style[origin_odd ? 0 : 1] << ' '
+                << num_sets << std::endl;
+      std::cerr << "actually: " << kind[is_max ? 0 : 1] << ' '
+                << style[is_odd ? 0 : 1] << ' '
+                << aut->num_sets() << std::endl;
+      std::cerr << std::endl;
+      return false;
+    }
+  return true;
+}
+
+static bool is_almost_colored(spot::const_twa_graph_ptr aut)
+{
+  for (auto t: aut->edges())
+    if (t.acc.count() > 1)
+      {
+        std::cerr << "======Not colored======" << std::endl;
+        spot::print_hoa(std::cerr, aut);
+        std::cerr << std::endl;
+        return false;
+      }
+  return true;
+}
+
+int main()
+{
+  auto current_bdd = spot::make_bdd_dict();
+  spot::srand(0);
+  auto parity_kinds =
+  {
+    spot::parity_kind_max,
+    spot::parity_kind_min,
+    spot::parity_kind_same,
+    spot::parity_kind_any,
+  };
+  auto parity_styles =
+  {
+    spot::parity_style_odd,
+    spot::parity_style_even,
+    spot::parity_style_same,
+    spot::parity_style_any,
+  };
+
+  auto acceptance_sets = generate_acc();
+  auto automata_tuples = generate_aut(current_bdd);
+
+  unsigned num_automata = automata_tuples.size();
+  unsigned num_acceptance = acceptance_sets.size();
+
+  std::cerr << "num of automata: " << num_automata << '\n';
+  std::cerr << "num of acceptance expression: " << num_acceptance << '\n';
+
+  for (auto acc_tuple: acceptance_sets)
+    for (auto& aut_tuple: automata_tuples)
+      {
+        auto& aut = aut_tuple.first;