gen_random.hxx

// gen_random.hxx: this file is part of the Vaucanson project.
//
// Vaucanson, a generic library for finite state machines.
//
// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2008 The
// Vaucanson Group.
//
// This program 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.
//
// The complete GNU General Public Licence Notice can be found as the
// `COPYING' file in the root directory.
//
// The Vaucanson Group consists of people listed in the `AUTHORS' file.
//
#ifndef VCSN_TOOLS_GEN_RANDOM_HXX
# define VCSN_TOOLS_GEN_RANDOM_HXX

# include <vaucanson/tools/gen_random.hh>
# include <vaucanson/misc/usual_macros.hh>

# include <cstdlib>

namespace vcsn {

  namespace tools {

    using namespace algebra;

    /*---------------------.
    | GenRandomAutomataSet |
    `---------------------*/

    template <class AutoSet>
      AutoSet
      GenRandomAutomataSet::generate(SELECTOR(AutomataBase<AutoSet>),
          unsigned nb_letter)
      {

        AUTOMATA_SET_TYPES(AutoSet);

        alphabet_t              alpha;
        unsigned                max = (alpha.max_size() > ALPHABET_MAX_SIZE ?
                                       ALPHABET_MAX_SIZE :
                                       alpha.max_size());
        unsigned                nb = alea(nb_letter ? nb_letter : max);
        for (unsigned i = 0; i < nb; ++i)
          alpha.insert(alpha.random_letter());

        monoid_t                monoid(alpha);
        semiring_t              semi;
        series_set_t    series(semi, monoid);
        automata_set_t  autoset(series);
        return autoset;
      }

    template <class AutoSet>
      AutoSet
      GenRandomAutomataSet::generate(SELECTOR(TransducerBase<AutoSet>),
          unsigned input_nb_letter,
          unsigned output_nb_letter)
      {
        AUTOMATA_SET_TYPES(AutoSet);

        alphabet_t      input_alpha;
        alphabet_t      output_alpha;

        unsigned        max = (input_alpha.max_size() > ALPHABET_MAX_SIZE ?
                               ALPHABET_MAX_SIZE :
                               input_alpha.max_size());
        unsigned        nb = alea(input_nb_letter ? input_nb_letter : max);
        for (unsigned i = 0; i < nb; ++i)
          input_alpha.insert(input_alpha.random_letter());

        max = (output_alpha.max_size() > ALPHABET_MAX_SIZE ?
               ALPHABET_MAX_SIZE :
               output_alpha.max_size());
        nb = alea(output_nb_letter ? output_nb_letter : max);
        for (unsigned i = 0; i < nb; ++i)
          output_alpha.insert(output_alpha.random_letter());

        monoid_t                        input_monoid(input_alpha);
        monoid_t                        output_monoid(output_alpha);

        typename semiring_t::semiring_t semi;
        semiring_t                      output_series(semi, output_monoid);

        series_set_t            series(output_series, input_monoid);

        automata_set_t          auto_set(series);
        return auto_set;
      }

    unsigned alea(unsigned max)
    {
      return int (1 + float (max) * rand() / (RAND_MAX + 1.0));
    }

    /*------------------.
    | GenRandomAutomata |
    `------------------*/

    template <class TAutomata, class AutomataSetGenerator>
      GenRandomAutomata<TAutomata, AutomataSetGenerator>::GenRandomAutomata()
      {}


    /*------.
    | empty |
    `------*/

    template <class TAutomata, class AutomataSetGenerator>
      TAutomata GenRandomAutomata<TAutomata, AutomataSetGenerator>::
      empty(unsigned nb_letter)
      {
        automata_set_t aset =
          GenRandomAutomataSet::generate(SELECT(automata_set_t), nb_letter);
        TAutomata work(aset);
        return work;
      }

    template <class TAutomata, class AutomataSetGenerator>
      TAutomata GenRandomAutomata<TAutomata, AutomataSetGenerator>::
      empty(const automata_set_t& set)
      {
        TAutomata work(set);
        return work;
      }

    /*---------.
    | generate |
    `---------*/

    template <class TAutomata, class AutomataSetGenerator>
      TAutomata GenRandomAutomata<TAutomata, AutomataSetGenerator>::
      generate(unsigned nb_state, unsigned nb_transition_,
          unsigned istate, unsigned fstate,
          unsigned nb_letter)
      {
        automata_set_t aset =
          GenRandomAutomataSet::generate(SELECT(automata_set_t), nb_letter);
        return generate(aset, nb_state, nb_transition_, istate, fstate);
      }

    template <class TAutomata, class AutomataSetGenerator>
      TAutomata GenRandomAutomata<TAutomata, AutomataSetGenerator>::
      generate(const automata_set_t& set,
          unsigned nb_state, unsigned nb_transition_,
          unsigned istate, unsigned fstate)
      {
        AUTOMATON_TYPES(TAutomata);
        AUTOMATON_FREEMONOID_TYPES(TAutomata);
        int nb_transition = nb_transition_;
        // check consistency of automaton
        if (nb_transition_ < nb_state - 1)
          nb_transition = nb_state - 1;
        if (fstate > nb_state) fstate = nb_state;
        if (fstate <= 0) fstate = 1;
        if (istate > nb_state) istate = nb_state;
        if (istate <= 0) istate = 1;

        TAutomata work(set);

        for (unsigned i = 0; i < nb_state; i++)
          work.add_state();

        // minimal construction
        state_iterator prev = work.states().begin();
        state_iterator i = prev;
        ++i;
        for (; i != work.states().end(); ++i)
        {
          nb_transition--;
          letter_t e = set.series().monoid().alphabet().choose();
          bool empty = true;
          for (delta_iterator t(work.value(), *prev);
               ! t.done() && empty;
               t.next())
          {
            monoid_elt_t w(work.series_of(*t).structure().monoid(), e);
            if (work.series_of(*t).get(w) != work.series().semiring().wzero_)
            {
              empty = false;
              break;
            }
          }

          if (empty &&
              algebra::letter_traits<letter_t>::letter_to_literal(e) != work.structure().series().monoid().representation()->empty)
            work.add_letter_transition(*prev, *i, e);
          prev = i;
        }

        for (int i = 0; i < nb_transition; i++)
        {
          std::set<hstate_t> dst;
          letter_t e = set.series().monoid().alphabet().choose();
          hstate_t s = work.choose_state();
          hstate_t a = work.choose_state();
          for (delta_iterator t(work.value(), s);
               ! t.done();
               t.next())
          {
            monoid_elt_t w(work.series_of(*t).structure().monoid(), e);
            if (work.series_of(*t).get(w) != work.series().semiring().wzero_)
              dst.insert(work.dst_of(*t));
          }
          if (dst.find(a) == dst.end() &&
              algebra::letter_traits<letter_t>::letter_to_literal(e) != work.structure().series().monoid().representation()->empty)
            work.add_letter_transition(s, a, e);
        }

        work.set_initial(*work.states().begin());
        // set initial states
        for (unsigned i = 1; i < istate; i++)
        {
          hstate_t tmp = work.choose_state();
          while (work.is_initial(tmp))
            tmp = work.choose_state();
          work.set_initial(tmp);
        }

        work.set_final(*--work.states().end());
        // set final states
        for (unsigned i = 1; i < fstate; i++)
        {
          hstate_t tmp = work.choose_state();
          while (work.is_final(tmp))
            tmp = work.choose_state();
          work.set_final(tmp);
        }

        return work;
      }

    /*---------------.
    | useful methods |
    `---------------*/

    template <class TAutomata, class AutomataSetGenerator>
      unsigned GenRandomAutomata<TAutomata, AutomataSetGenerator>::
      nb_transition_circle(TAutomata work, hstate_t state)
      {
        AUTOMATON_TYPES(TAutomata);
        unsigned res = 0;

        for_all_transitions(i, work)
          if ((work.src_of(*i) == state) && (work.dst_of(*i) == state))
            res++;

        return res;
      }

    template <class TAutomata, class AutomataSetGenerator>
      void GenRandomAutomata<TAutomata, AutomataSetGenerator>::
      del_transition_circle(TAutomata& work, hstate_t state)
      {
        AUTOMATON_TYPES(TAutomata);

        std::list<htransition_t> to_remove;
        for_all_transitions(i, work)
        {
          if ((work.src_of(*i) == state) && (work.dst_of(*i) == state))
            to_remove.push_back(*i);
        }
        for_all_const_(std::list<htransition_t>, e, to_remove)
          work.del_transition(*e);
      }


    /*----------------------.
    | generate with epsilon |
    `----------------------*/

    template <class TAutomata, class AutomataSetGenerator>
      TAutomata GenRandomAutomata<TAutomata, AutomataSetGenerator>::
      generate_with_epsilon(unsigned nb_state,
          unsigned nb_transition,
          unsigned nb_epsilon_min,
          unsigned nb_epsilon_max)
      {
        automata_set_t aset =
          GenRandomAutomataSet::generate(SELECT(automata_set_t));
        TAutomata a = generate_with_epsilon(aset, nb_state, nb_transition,
            nb_epsilon_min, nb_epsilon_max);
        return a;
      }



    template <class TAutomata, class AutomataSetGenerator>
      TAutomata GenRandomAutomata<TAutomata, AutomataSetGenerator>::
      generate_with_epsilon(const automata_set_t& set,
          unsigned nb_state,
          unsigned nb_transition,
          unsigned nb_epsilon_min,
          unsigned nb_epsilon_max)
      {
        TAutomata a = generate(set, nb_state, nb_transition);
        unsigned nb_eps = nb_epsilon_min + alea(nb_epsilon_max - nb_epsilon_min);

        for (unsigned i = 0; i < nb_eps; ++i)
        {
          hstate_t f = a.choose_state();
          hstate_t t = a.choose_state();
          a.add_spontaneous(f, t);
        }
        return a;
      }


    /*-------------.
    | generate dfa |
    `-------------*/

    template <class TAutomata, class AutomataSetGenerator>
      TAutomata GenRandomAutomata<TAutomata, AutomataSetGenerator>::
      generate_dfa(unsigned nb_state,
          unsigned size_alphabet,
          unsigned fstate)
      {
        automata_set_t aset =
          GenRandomAutomataSet::generate(SELECT(automata_set_t), size_alphabet);
        TAutomata a = generate_dfa(aset, nb_state, fstate);
        return a;
      }



    template <class TAutomata, class AutomataSetGenerator>
      TAutomata GenRandomAutomata<TAutomata, AutomataSetGenerator>::
      generate_dfa(const automata_set_t& set,
          unsigned nb_state,
          unsigned fstate)
      {
        AUTOMATON_TYPES(TAutomata);
        AUTOMATON_FREEMONOID_TYPES(TAutomata);
        automaton_t work(set);

        for (unsigned i = 0; i < nb_state; i++)
          work.add_state();

        for_all_states(i, work)
        {
          for_all_letters(j, set.series().monoid().alphabet())
            work.add_letter_transition(*i,work.choose_state(),*j);
          while (nb_transition_circle(work, *i) == set.series().monoid().alphabet().size())
          {
            del_transition_circle(work, *i);
            for_all_letters(j, set.series().monoid().alphabet())
            {
              bool empty = true;
              for (delta_iterator t(work.value(), *i);
                   ! t.done() && empty;
                   t.next())
              {
                monoid_elt_t w(work.series_of(*t).structure().monoid(), *j);
                if (work.series_of(*t).get(w) != work.series().semiring().wzero_)
                {
                  empty = false;
                  break;
                }
              }
              if (empty)
              {
                hstate_t s;
                while ((s = work.choose_state()) == *i) ;
                work.add_letter_transition(*i, s, *j);
              }
            }
          }
        }

        // set initial states
        work.set_initial(work.choose_state());

        // set final states
        for (unsigned i = 0; i < fstate; i++)
        {
          hstate_t tmp = work.choose_state();
          while (work.is_final(tmp))
            tmp = work.choose_state();
          work.set_final(tmp);
        }
        return work;
      }


    /*--------------------.
    | generate normalized |
    `--------------------*/

    template <class TAutomata, class AutomataSetGenerator>
      TAutomata GenRandomAutomata<TAutomata, AutomataSetGenerator>::
      generate_normalized(unsigned nb_state, unsigned density)
      {
        automata_set_t aset =
          AutomataSetGenerator::generate(SELECT(automata_set_t));
        TAutomata a = generate_normalized(aset, nb_state, density);
        return a;
      }

    template <class TAutomata, class AutomataSetGenerator>
      TAutomata GenRandomAutomata<TAutomata, AutomataSetGenerator>::
      generate_normalized(const automata_set_t& set,
          unsigned nb_state,
          unsigned density)
      {
        typedef typename TAutomata::state_iterator state_iterator;
        typedef typename TAutomata::monoid_t::alphabets_elt_t alphabets_elt_t;

        if (density == 0)
          density = 1;

        TAutomata work = generate(set, nb_state,
            nb_state + alea(nb_state * density));

        for (state_iterator i = work.states().begin(); i != work.states().end();
            i++)
        {
          if (work.is_initial(*i))
            work.unset_initial(*i);
          if (work.is_final(*i))
            work.unset_final(*i);
        }

        hstate_t init = work.add_state();
        hstate_t final = work.add_state();

        work.set_initial(init);
        work.set_final(final);

        const alphabets_elt_t&
          alpha = work.structure().series().monoid().alphabet();

        hstate_t tmp;

        for (unsigned i = 0; i < density; i++)
          if ((tmp = work.choose_state()) != init)
            work.add_letter_transition(init, tmp,
                                       alpha.choose());

        for (unsigned i =0; i < density; i++)
          if ((tmp = work.choose_state()) != final)
            work.add_letter_transition(tmp, final,
                alpha.choose());

        return work;
      }

  } // ! tools

} // ! vcsn

#endif // ! VCSN_TOOLS_GEN_RANDOM_HXX

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