tgba.hh 10.1 KB
Newer Older
1
// Copyright (C) 2009, 2011 Laboratoire de Recherche et Développement
Guillaume Sadegh's avatar
Guillaume Sadegh committed
2 3
// de l'Epita (LRDE).
// Copyright (C) 2003, 2004, 2005 Laboratoire d'Informatique de
4 5
// Paris 6 (LIP6), département Systèmes Répartis Coopératifs (SRC),
// Université Pierre et Marie Curie.
Alexandre Duret-Lutz's avatar
Alexandre Duret-Lutz committed
6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
//
// 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.

24 25 26
#ifndef SPOT_TGBA_TGBA_HH
# define SPOT_TGBA_TGBA_HH

27
#include "state.hh"
28
#include "succiter.hh"
29
#include "bdddict.hh"
30 31 32

namespace spot
{
33
  /// \defgroup tgba TGBA (Transition-based Generalized Büchi Automata)
34 35 36 37 38 39 40 41 42 43 44 45
  ///
  /// Spot is centered around the spot::tgba type.  This type and its
  /// cousins are listed \ref tgba_essentials "here".  This is an
  /// abstract interface.  Its implementations are either \ref
  /// tgba_representation "concrete representations", or \ref
  /// tgba_on_the_fly_algorithms "on-the-fly algorithms".  Other
  /// algorithms that work on spot::tgba are \ref tgba_algorithms
  /// "listed separately".

  /// \addtogroup tgba_essentials Essential TGBA types
  /// \ingroup tgba

46
  /// \brief A Transition-based Generalized Büchi Automaton.
47
  /// \ingroup tgba_essentials
48 49 50 51 52 53 54 55
  ///
  /// The acronym TGBA (Transition-based Generalized Büchi Automaton)
  /// was coined by Dimitra Giannakopoulou and Flavio Lerda
  /// in "From States to Transitions: Improving Translation of LTL
  /// Formulae to Büchi Automata".  (FORTE'02)
  ///
  /// TGBAs are transition-based, meanings their labels are put
  /// on arcs, not on nodes.  They use Generalized Büchi acceptance
56
  /// conditions: there are several acceptance sets (of
Alexandre Duret-Lutz's avatar
typos  
Alexandre Duret-Lutz committed
57
  /// transitions), and a path can be accepted only if it traverses
58 59
  /// at least one transition of each set infinitely often.
  ///
Alexandre Duret-Lutz's avatar
typos  
Alexandre Duret-Lutz committed
60
  /// Browsing such automaton can be achieved using two functions:
61
  /// \c get_init_state, and \c succ_iter.  The former returns
Alexandre Duret-Lutz's avatar
typos  
Alexandre Duret-Lutz committed
62
  /// the initial state while the latter lists the
63 64 65 66 67 68
  /// successor states of any state.
  ///
  /// Note that although this is a transition-based automata,
  /// we never represent transitions!  Transition informations are
  /// obtained by querying the iterator over the successors of
  /// a state.
69 70
  class tgba
  {
71 72
  protected:
    tgba();
73

74
  public:
75 76
    virtual ~tgba();

77 78 79
    /// \brief Get the initial state of the automaton.
    ///
    /// The state has been allocated with \c new.  It is the
80
    /// responsability of the caller to \c destroy it when no
81 82
    /// longer needed.
    virtual state* get_init_state() const = 0;
83

84
    /// \brief Get an iterator over the successors of \a local_state.
85 86 87 88 89
    ///
    /// The iterator has been allocated with \c new.  It is the
    /// responsability of the caller to \c delete it when no
    /// longer needed.
    ///
90 91 92 93 94 95 96 97 98
    /// During synchornized products, additional informations are
    /// passed about the entire product and its state.  Recall that
    /// products can be nested, forming a tree of spot::tgba where
    /// most values are computed on demand.  \a global_automaton
    /// designate the root spot::tgba, and \a global_state its
    /// state.  This two objects can be used by succ_iter() to
    /// restrict the set of successors to compute.
    ///
    /// \param local_state The state whose successors are to be explored.
99
    /// This pointer is not adopted in any way by \c succ_iter, and
100
    /// it is still the caller's responsability to destroy it when
101 102
    /// appropriate (this can be done during the lifetime of
    /// the iterator).
103 104 105
    /// \param global_state In a product, the state of the global
    /// product automaton.  Otherwise, 0.  Like \a locale_state,
    /// \a global_state is not adopted by \c succ_iter.
106
    /// \param global_automaton In a product, the global
107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140
    /// product automaton.  Otherwise, 0.
    virtual tgba_succ_iterator*
    succ_iter(const state* local_state,
	      const state* global_state = 0,
	      const tgba* global_automaton = 0) const = 0;

    /// \brief Get a formula that must hold whatever successor is taken.
    ///
    /// \return A formula which must be verified for all successors
    ///  of \a state.
    ///
    /// This can be as simple as \c bddtrue, or more completely
    /// the disjunction of the condition of all successors.  This
    /// is used as an hint by \c succ_iter() to reduce the number
    /// of successor to compute in a product.
    ///
    /// Sub classes should implement compute_support_conditions(),
    /// this function is just a wrapper that will cache the
    /// last return value for efficiency.
    bdd support_conditions(const state* state) const;

    /// \brief Get the conjunctions of variables tested by
    ///        the outgoing transitions of \a state.
    ///
    /// All variables tested by outgoing transitions must be
    /// returned.  This is mandatory.
    ///
    /// This is used as an hint by some \c succ_iter() to reduce the
    /// number of successor to compute in a product.
    ///
    /// Sub classes should implement compute_support_variables(),
    /// this function is just a wrapper that will cache the
    /// last return value for efficiency.
    bdd support_variables(const state* state) const;
141 142 143 144 145 146 147 148

    /// \brief Get the dictionary associated to the automaton.
    ///
    /// State are represented as BDDs.  The dictionary allows
    /// to map BDD variables back to formulae, and vice versa.
    /// This is useful when dealing with several automata (which
    /// may use the same BDD variable for different formula),
    /// or simply when printing.
149
    virtual bdd_dict* get_dict() const = 0;
150 151 152 153

    /// \brief Format the state as a string for printing.
    ///
    /// This formating is the responsability of the automata
154
    /// that owns the state.
155
    virtual std::string format_state(const state* state) const = 0;
156

157 158 159
    /// \brief Return a possible annotation for the transition
    /// pointed to by the iterator.
    ///
160 161 162 163 164
    /// You may decide to use annotations when building a tgba class
    /// that represents the state space of a model, for instance to
    /// indicate how the tgba transitions relate to the original model
    /// (e.g. the annotation could be the name of a PetriNet
    /// transition, or the line number of some textual formalism).
165
    ///
166 167 168 169 170 171 172
    /// Implementing this method is optional; the default annotation
    /// is the empty string.
    ///
    /// This method is used for instance in dotty_reachable(),
    /// and replay_tgba_run().
    ///
    /// \param t a non-done tgba_succ_iterator for this automaton
173 174 175
    virtual std::string
    transition_annotation(const tgba_succ_iterator* t) const;

176
    /// \brief Project a state on an automaton.
177 178 179 180 181 182 183 184 185 186 187
    ///
    /// This converts \a s, into that corresponding spot::state for \a
    /// t.  This is useful when you have the state of a product, and
    /// want restrict this state to a specific automata occuring in
    /// the product.
    ///
    /// It goes without saying that \a s and \a t should be compatible
    /// (i.e., \a s is a state of \a t).
    ///
    /// \return 0 if the projection fails (\a s is unrelated to \a t),
    ///    or a new \c state* (the projected state) that must be
188
    ///    destroyed by the caller.
189 190
    virtual state* project_state(const state* s, const tgba* t) const;

191
    /// \brief Return the set of all acceptance conditions used
192 193 194 195 196 197 198
    /// by this automaton.
    ///
    /// The goal of the emptiness check is to ensure that
    /// a strongly connected component walks through each
    /// of these acceptiong conditions.  I.e., the union
    /// of the acceptiong conditions of all transition in
    /// the SCC should be equal to the result of this function.
199
    virtual bdd all_acceptance_conditions() const = 0;
200

201
    /// The number of acceptance conditions.
202
    virtual unsigned int number_of_acceptance_conditions() const;
203

204
    /// \brief Return the conjuction of all negated acceptance
205
    /// variables.
206
    ///
207
    /// For instance if the automaton uses variables <tt>Acc[a]</tt>,
208
    /// <tt>Acc[b]</tt> and <tt>Acc[c]</tt> to describe acceptance sets,
209
    /// this function should return <tt>!Acc[a]\&!Acc[b]\&!Acc[c]</tt>.
210
    ///
211
    /// This is useful when making products: each operand's condition
212
    /// set should be augmented with the neg_acceptance_conditions() of
213
    /// the other operand.
214
    virtual bdd neg_acceptance_conditions() const = 0;
215 216 217 218 219 220

  protected:
    /// Do the actual computation of tgba::support_conditions().
    virtual bdd compute_support_conditions(const state* state) const = 0;
    /// Do the actual computation of tgba::support_variables().
    virtual bdd compute_support_variables(const state* state) const = 0;
221
  protected:
222 223
    mutable const state* last_support_conditions_input_;
    mutable const state* last_support_variables_input_;
224 225
  private:
    mutable bdd last_support_conditions_output_;
226
    mutable bdd last_support_variables_output_;
227
    mutable int num_acc_;
228
  };
229

230 231 232 233 234
  /// \addtogroup tgba_representation TGBA representations
  /// \ingroup tgba

  /// \addtogroup tgba_algorithms TGBA algorithms
  /// \ingroup tgba
235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252

  /// \addtogroup tgba_on_the_fly_algorithms TGBA on-the-fly algorithms
  /// \ingroup tgba_algorithms

  /// \addtogroup tgba_io Input/Output of TGBA
  /// \ingroup tgba_algorithms

  /// \addtogroup tgba_ltl Translating LTL formulae into TGBA
  /// \ingroup tgba_algorithms

  /// \addtogroup tgba_generic Algorithm patterns
  /// \ingroup tgba_algorithms

  /// \addtogroup tgba_reduction TGBA simplifications
  /// \ingroup tgba_algorithms

  /// \addtogroup tgba_misc Miscellaneous algorithms on TGBA
  /// \ingroup tgba_algorithms
253
}
254 255

#endif // SPOT_TGBA_TGBA_HH