Add a new algorithm (from Tauriainen) to translate LTL formulae to

TGBA which uses TAA as an intermediate representation.  This is a
basic version, optimizations and enhancements will come later.

* src/tgbaalgos/ltl2taa.cc, src/tgbaalgos/ltl2taa.hh: The algortihm.
* src/tgbaalgos/Makefile.am: Adjust.
* src/tgbatest/ltl2tgba: New option: -taa, which uses this new
translation algorithm.
* src/tgbatest/spotlbtt.test: Add ltl2tgba -taa.

ChangeLog

+2009-10-16  Damien Lefortier <dam@lrde.epita.fr>
+
+	Add a new algorithm (from Tauriainen) to translate LTL formulae to
+	TGBA which uses TAA as an intermediate representation.  This is a
+	basic version, optimizations and enhancements will come later.
+
+	* src/tgbaalgos/ltl2taa.cc, src/tgbaalgos/ltl2taa.hh: The algortihm.
+	* src/tgbaalgos/Makefile.am: Adjust.
+	* src/tgbatest/ltl2tgba: New option: -taa, which uses this new
+	translation algorithm.
+	* src/tgbatest/spotlbtt.test: Add ltl2tgba -taa.
+
 2009-10-04  Damien Lefortier <dam@lrde.epita.fr>
 
 	Add a class to represent Transition-based Alternating Automata (TAA).

src/tgbaalgos/Makefile.am

@@ -38,6 +38,7 @@ tgbaalgos_HEADERS = \
   emptiness_stats.hh \
   gv04.hh \
   lbtt.hh \
+  ltl2taa.hh \
   ltl2tgba_fm.hh \
   ltl2tgba_lacim.hh \
   magic.hh \
@@ -69,6 +70,7 @@ libtgbaalgos_la_SOURCES = \
   emptiness.cc \
   gv04.cc \
   lbtt.cc \
+  ltl2taa.cc \
   ltl2tgba_fm.cc \
   ltl2tgba_lacim.cc \
   magic.cc \

src/tgbaalgos/ltl2taa.cc

+// Copyright (C) 2009 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.
+
+#include <utility>
+#include "ltlast/visitor.hh"
+#include "ltlast/allnodes.hh"
+#include "ltlvisit/lunabbrev.hh"
+#include "ltlvisit/tunabbrev.hh"
+#include "ltlvisit/nenoform.hh"
+#include "ltlvisit/destroy.hh"
+#include "ltlvisit/tostring.hh"
+#include "ltlvisit/clone.hh"
+#include "ltl2taa.hh"
+
+namespace spot
+{
+  namespace
+  {
+    using namespace ltl;
+
+    /// \brief Recursively translate a formula into a TAA.
+    class ltl2taa_visitor : public const_visitor
+    {
+    public:
+      ltl2taa_visitor(taa* res, bool negated = false)
+	: res_(res), negated_(negated), init_(), succ_(), to_free_()
+      {
+      }
+
+      virtual
+      ~ltl2taa_visitor()
+      {
+      }
+
+      taa*
+      result()
+      {
+	for (unsigned i = 0; i < to_free_.size(); ++i)
+	  destroy(to_free_[i]);
+	res_->set_init_state(init_);
+	return res_;
+      }
+
+      void
+      visit(const atomic_prop* node)
+      {
+	const formula* f = node; // Handle negation
+	if (negated_)
+	{
+	  f = unop::instance(unop::Not, clone(node));
+	  to_free_.push_back(f);
+	}
+	init_ = to_string(f);
+	std::vector<std::string> dst;
+
+	dst.push_back(std::string("well"));
+	taa::transition* t = res_->create_transition(init_, dst);
+	res_->add_condition(t, clone(f));
+
+	succ_.push_back(std::make_pair(dst, f));
+      }
+
+      void
+      visit(const constant* node)
+      {
+	init_ = to_string(node);
+	std::vector<std::string> dst;
+	switch (node->val())
+	{
+	  case constant::True:
+	    dst.push_back(std::string("well"));
+	    res_->create_transition(init_, dst);
+	    succ_.push_back(std::make_pair(dst, node));
+	    return;
+	  case constant::False:
+	    return;
+	}
+	/* Unreachable code.  */
+	assert(0);
+      }
+
+      void
+      visit(const unop* node)
+      {
+	negated_ = node->op() == unop::Not;
+	ltl2taa_visitor v = recurse(node->child());
+
+	init_ = to_string(node);
+	std::vector<std::string> dst;
+	switch (node->op())
+	{
+	  case unop::X:
+	    if (v.succ_.size() == 0) // Handle X(0)
+	      return;
+	    dst.push_back(v.init_);
+	    res_->create_transition(init_, dst);
+	    succ_.push_back(std::make_pair(dst, constant::true_instance()));
+	    return;
+	  case unop::F:
+	  case unop::G:
+	    assert(0); // TBD
+	    return;
+	  case unop::Not:
+	    // Done in recurse
+	    succ_ = v.succ_;
+	    return;
+	  case unop::Finish:
+	    assert(!"unsupported operator");
+	}
+	/* Unreachable code.  */
+	assert(0);
+      }
+
+      void
+      visit(const binop* node)
+      {
+	ltl2taa_visitor v1 = recurse(node->first());
+	ltl2taa_visitor v2 = recurse(node->second());
+
+	init_ = to_string(node);
+	std::vector<succ_state>::iterator i1;
+	std::vector<succ_state>::iterator i2;
+	taa::transition* t = 0;
+	switch (node->op())
+	{
+	  case binop::U: // Strong
+	    for (i1 = v1.succ_.begin(); i1 != v1.succ_.end(); ++i1)
+	    {
+	      i1->first.push_back(init_); // Add the initial state
+	      t = res_->create_transition(init_, i1->first);
+	      res_->add_condition(t, clone(i1->second));
+	      res_->add_acceptance_condition(t, clone(node));
+	      succ_.push_back(*i1);
+	    }
+	    for (i2 = v2.succ_.begin(); i2 != v2.succ_.end(); ++i2)
+	    {
+	      t = res_->create_transition(init_, i2->first);
+	      res_->add_condition(t, clone(i2->second));
+	      succ_.push_back(*i2);
+	    }
+	    return;
+	  case binop::R: // Weak
+	    for (i2 = v2.succ_.begin(); i2 != v2.succ_.end(); ++i2)
+	    {
+	      for (i1 = v1.succ_.begin(); i1 != v1.succ_.end(); ++i1)
+	      {
+		std::vector<std::string> u; // Union
+		std::copy(i1->first.begin(), i1->first.end(), ii(u, u.begin()));
+		std::copy(i2->first.begin(), i2->first.end(), ii(u, u.begin()));
+		const formula* f = multop::instance
+		  (multop::And, clone(i1->second), clone(i2->second));
+		to_free_.push_back(f);
+
+		t = res_->create_transition(init_, u);
+		res_->add_condition(t, clone(f));
+		succ_.push_back(std::make_pair(u, f));
+	      }
+
+	      i2->first.push_back(init_); // Add the initial state
+	      t = res_->create_transition(init_, i2->first);
+	      res_->add_condition(t, clone(i2->second));
+	      succ_.push_back(*i2);
+	    }
+	    return;
+	  case binop::Xor:
+	  case binop::Implies:
+	  case binop::Equiv:
+	    assert(0); // TBD
+	}
+	/* Unreachable code.  */
+	assert(0);
+      }
+
+      void
+      visit(const multop* node)
+      {
+	bool ok = true;
+	std::vector<ltl2taa_visitor> vs;
+	for (unsigned n = 0; n < node->size(); ++n)
+	{
+	  vs.push_back(recurse(node->nth(n)));
+	  if (vs[n].succ_.size() == 0) // Handle 0
+	    ok = false;
+	}
+
+	init_ = to_string(node);
+	std::vector<succ_state>::iterator i;
+	taa::transition* t = 0;
+	switch (node->op())
+	{
+	  case multop::And:
+	  {
+	    std::vector<succ_state> p = all_n_tuples(vs);
+	    for (unsigned n = 0; n < p.size() && ok; ++n)
+	    {
+	      t = res_->create_transition(init_, p[n].first);
+	      res_->add_condition(t, clone(p[n].second));
+	      succ_.push_back(p[n]);
+	    }
+	    return;
+	  }
+	  case multop::Or:
+	    for (unsigned n = 0; n < node->size(); ++n)
+	      for (i = vs[n].succ_.begin(); i != vs[n].succ_.end(); ++i)
+	      {
+		t = res_->create_transition(init_, i->first);
+		res_->add_condition(t, clone(i->second));
+		succ_.push_back(*i);
+	      }
+	    return;
+	}
+	/* Unreachable code.  */
+	assert(0);
+      }
+
+      void
+      visit(const automatop* node)
+      {
+	(void) node;
+	assert(!"unsupported operator");
+      }
+
+      ltl2taa_visitor
+      recurse(const formula* f)
+      {
+	ltl2taa_visitor v(res_, negated_);
+	f->accept(v);
+	for (unsigned i = 0; i < v.to_free_.size(); ++i)
+	  to_free_.push_back(v.to_free_[i]);
+	return v;
+      }
+
+    private:
+      taa* res_;
+      bool negated_;
+
+      typedef std::insert_iterator<
+	std::vector<std::string>
+      > ii;
+
+      typedef std::pair<
+        std::vector<std::string>, const formula*
+      > succ_state;
+
+      std::string init_;
+      std::vector<succ_state> succ_;
+
+      std::vector<const formula*> to_free_;
+
+    public:
+      std::vector<succ_state>
+      all_n_tuples(const std::vector<ltl2taa_visitor>& vs)
+      {
+	std::vector<succ_state> product;
+
+	std::vector<int> pos;
+	for (unsigned i = 0; i < vs.size(); ++i)
+	  pos.push_back(vs[i].succ_.size());
+
+	while (pos[0] != 0)
+	{
+	  std::vector<std::string> u; // Union
+	  formula* f = constant::true_instance();
+	  for (unsigned i = 0; i < vs.size(); ++i)
+	  {
+	    if (vs[i].succ_.size() == 0)
+	      continue;
+	    const succ_state& ss(vs[i].succ_[pos[i] - 1]);
+	    std::copy(ss.first.begin(), ss.first.end(), ii(u, u.begin()));
+	    f = multop::instance(multop::And, clone(ss.second), f);
+	  }
+	  to_free_.push_back(f);
+	  product.push_back(std::make_pair(u, f));
+
+	  for (int i = vs.size() - 1; i >= 0; --i)
+	  {
+	    if (vs[i].succ_.size() == 0)
+	      continue;
+	    if (pos[i] > 1 || (i == 0 && pos[0] == 1))
+	    {
+	      --pos[i];
+	      break;
+	    }
+	    else
+	      pos[i] = vs[i].succ_.size();
+	  }
+	}
+	return product;
+      }
+    };
+  } // anonymous
+
+  taa*
+  ltl_to_taa(const ltl::formula* f, bdd_dict* dict)
+  {
+    // TODO: s/unabbreviate_ltl/unabbreviate_logic/
+    const ltl::formula* f1 = ltl::unabbreviate_ltl(f);
+    const ltl::formula* f2 = ltl::negative_normal_form(f1);
+    ltl::destroy(f1);
+
+    std::cerr << ltl::to_string(f2) << std::endl;
+
+    taa* res = new spot::taa(dict);
+    ltl2taa_visitor v(res);
+    f2->accept(v);
+    ltl::destroy(f2);
+
+    return v.result();
+  }
+}

src/tgbaalgos/ltl2taa.hh

+// Copyright (C) 2009 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.
+
+#ifndef SPOT_TAAALGOS_LTL2TAA_HH_
+# define SPOT_TAAALGOS_LTL2TAA_HH_
+
+#include "ltlast/formula.hh"
+#include "tgba/taa.hh"
+
+namespace spot
+{
+  /// \brief Build a spot::taa* from an LTL formula.
+  ///
+  /// This is based on the following.
+  /// \verbatim
+  /// @techreport{HUT-TCS-A104,
+  ///     address = {Espoo, Finland},
+  ///     author  = {Heikki Tauriainen},
+  ///     month   = {September},
+  ///     note    = {Doctoral dissertation},
+  ///     number  = {A104},
+  ///     pages   = {xii+229},
+  ///     title   = {Automata and Linear Temporal Logic: Translations
+  ///                with Transition-Based Acceptance},
+  ///     type    = {Research Report},
+  ///     year    = {2006}
+  /// }
+  /// \endverbatim
+  ///
+  /// \param f The formula to translate into an automaton.
+  /// \param dict The spot::bdd_dict the constructed automata should use.
+  /// \return A spot::taa that recognizes the language of \a f.
+  taa* ltl_to_taa(const ltl::formula* f, bdd_dict* dict);
+}
+
+#endif /* !SPOT_TAAALGOS_LTL2TAA_HH_ */

src/tgbatest/ltl2tgba.cc

@@ -33,6 +33,7 @@
 #include "ltlparse/public.hh"
 #include "tgbaalgos/ltl2tgba_lacim.hh"
 #include "tgbaalgos/ltl2tgba_fm.hh"
+#include "tgbaalgos/ltl2taa.hh"
 #include "tgba/bddprint.hh"
 #include "tgbaalgos/save.hh"
 #include "tgbaalgos/dotty.hh"
@@ -79,6 +80,7 @@ syntax(char* prog)
 	    << "  -E[ALGO]  emptiness-check, expect no accepting run"
 	    << std::endl
             << "  -f    use Couvreur's FM algorithm for translation"
+            << "  -taa  use Tauriainen's TAA-based algorithm for translation"
 	    << std::endl
 	    << "  -fr1  use -r1 (see below) at each step of FM" << std::endl
 	    << "  -fr2  use -r2 (see below) at each step of FM" << std::endl
@@ -172,6 +174,7 @@ main(int argc, char** argv)
   bool paper_opt = false;
   enum { NoDegen, DegenTBA, DegenSBA } degeneralize_opt = NoDegen;
   enum { TransitionLabeled, StateLabeled } labeling_opt = TransitionLabeled;
+  bool taa_opt = false;
   bool fm_opt = false;
   int fm_red = spot::ltl::Reduce_None;
   bool fm_exprop_opt = false;
@@ -279,6 +282,10 @@ main(int argc, char** argv)
           expect_counter_example = false;
           output = -1;
         }
+      else if (!strcmp(argv[formula_index], "-taa"))
+	{
+	  taa_opt = true;
+	}
       else if (!strcmp(argv[formula_index], "-f"))
 	{
 	  fm_opt = true;
@@ -584,7 +591,10 @@ main(int argc, char** argv)
 					       fair_loop_approx, unobservables,
 					       fm_red, containment);
 	  else
-	    to_free = a = concrete = spot::ltl_to_tgba_lacim(f, dict);
+	    if (taa_opt)
+	      to_free = a = spot::ltl_to_taa(f, dict);
+	    else
+	      to_free = a = concrete = spot::ltl_to_tgba_lacim(f, dict);
 	}
 
       spot::tgba_tba_proxy* degeneralized = 0;

src/tgbatest/spotlbtt.test

@@ -73,7 +73,7 @@ Algorithm
    Name = "Spot (Couvreur -- LaCIM), eltl + delete_unaccepting_scc"
    Path = "${LBTT_TRANSLATE}"
    Parameters = "--spot '../eltl2tgba -L'"
-   Enabled = yes
+   Enabled = no
 }
 
 Algorithm
@@ -262,6 +262,14 @@ Algorithm
    Enabled = yes
 }
 
+Algorithm
+{
+   Name = "Spot (Tauriainen -- TAA)"
+   Path = "${LBTT_TRANSLATE}"
+   Parameters = "--spot '../ltl2tgba -F -taa -t'"
+   Enabled = yes
+}
+
 GlobalOptions
 {
    Rounds = 100