r.hh

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// This file is part of Awali.
// Copyright 2016-2023 Sylvain Lombardy, Victor Marsault, Jacques Sakarovitch
//
// Awali is a 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.
//
// This program 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/>.
 
#ifndef AWALI_WEIGHTSET_R_HH
# define AWALI_WEIGHTSET_R_HH
 
# include <string>
# include <ostream>
 
#include <awali/sttc/misc/raise.hh>
#include <awali/common/enums.hh>
#include <awali/sttc/misc/stream.hh>
#include <awali/sttc/weightset/q.hh>
#include <awali/sttc/weightset/lr_parse_number.hh>
 
namespace awali {
  namespace sttc {
    class r {
  public:
    using self_type = r;
 
    static std::string sname()
    {
      return "r";
    }
 
    std::string vname(bool = true) const
    {
      return sname();
    }
 
    static r make(std::istream& is)
    {
      eat(is, sname());
      return {};
    }
 
    using value_t = double;
 
    static value_t
    zero()
    {
      return 0.;
    }
 
    static value_t
    one()
    {
      return 1.;
    }
 
    static value_t
    add(const value_t l, const value_t r)
    {
      return l + r;
    }
 
    static value_t
    sub(const value_t l, const value_t r)
    {
      return l - r;
    }
 
    static value_t
    mul(const value_t l, const value_t r)
    {
      return l * r;
    }
 
    static value_t
    rdiv(const value_t l, const value_t r)
    {
      require(!is_zero(r), "div: division by zero");
      return l / r;
    }
 
    static value_t
    ldiv(const value_t l, const value_t r)
    {
      return rdiv(r, l);
    }
 
    value_t
    star(const value_t v) const
    {
      if (-1 < v && v < 1)
        return 1/(1-v);
      else
        raise(sname(), ": star: invalid value: ", format(*this, v));
    }
 
    value_t
    plus(const value_t v) const
    {
      if (-1 < v && v < 1)
        return v/(1-v);
      else
        raise(sname(), ": star: invalid value: ", format(*this, v));
    }
 
    constexpr static bool is_special(value_t)
    {
      return false;
    }
 
    static bool
    is_zero(const value_t v)
    {
      return v == 0;
    }
 
    static bool
    is_one(const value_t v)
    {
      return v == 1;
    }
 
    static bool
    equals(const value_t l, const value_t r)
    {
      return l == r;
    }
 
    static bool less_than(value_t lhs, value_t rhs)
    {
      return lhs < rhs;
    }
 
    static constexpr bool is_commutative_semiring() { return true; }
 
    static constexpr bool show_one() { return false; }
    static constexpr star_status_t star_status() { return star_status_t::ABSVAL; }
 
    static value_t
    abs(const value_t v)
    {
      return v < 0 ? -v : v;
    }
 
    static value_t
    transpose(const value_t v)
    {
      return v;
    }
 
    static size_t hash(value_t v)
    {
      return utils::hash_value(v);
    }
 
    static value_t
    conv(self_type, value_t v)
    {
      return v;
    }
 
    static value_t
    conv(q, q::value_t v)
    {
      return value_t(v.num) / value_t(v.den);
    }
 
    static value_t
    conv(z, z::value_t v)
    {
      return v;
    }
 
    static value_t
    conv(n, n::value_t v)
    {
      return (value_t)v;
    }
 
    static value_t
    conv(b, b::value_t v)
    {
      return v;
    }
 
    static value_t
    conv(std::istream& i)
    {
      value_t res;
      if (i >> res)
        return res;
      else
        fail_reading(i, sname() + ": invalid value");
    }
 
    static value_t
    parse(const std::string & s, size_t& p) {
      return internal::lr_parse_double(s,p);
    }
 
    static std::ostream&
    print(const value_t v, std::ostream& o,
          const std::string& /*format*/ = "text")
    {
      o << v;
      return o;
    }
 
    std::ostream&
    print_set(std::ostream& o, const std::string& format = "text") const
    {
      if (format == "latex")
        o << "\\mathbb{R}";
      else if (format == "text")
        o << "R";
      else
        raise("invalid format: ", format);
      return o;
    }
    
    template<unsigned version = version::fsm_json>
    static
    json::node_t* to_json()
    {
      version::check_fsmjson<version>();
      switch (version) {
        case 0: /* Never occurs due to above check. */
        case 1:
        default:
          return new json::object_t("semiring",new json::string_t("R"));
      }
    }
 
    template<unsigned version = version::fsm_json>
    json::node_t* value_to_json(value_t v) 
    const
    {
      version::check_fsmjson<version>();
      switch (version) {
        case 0: /* Never occurs due to above check. */
        case 1:
        default:
          return new json::float_t(v);
      }
    }
    
    template<unsigned version = version::fsm_json>
    value_t value_from_json(json::node_t const* p) 
    const
    {
      version::check_fsmjson<version>();
      switch (version) {
        case 0: /* Never occurs due to above check. */
        case 1:
        default:
          return p->to_double();
      }
    }
    
  };
 
  inline r join(const r&, const r&) { return {}; }
 
  inline r join(const q&, const r&) { return {}; }
  inline r join(const r&, const q&) { return {}; }
 
  inline r join(const z&, const r&) { return {}; }
  inline r join(const r&, const z&) { return {}; }
 
  inline r join(const n&, const r&) { return {}; }
  inline r join(const r&, const n&) { return {}; }
 
  inline r join(const b&, const r&) { return {}; }
  inline r join(const r&, const b&) { return {}; }
 
}}//end of ns awali::stc
 
#endif // !AWALI_WEIGHTSET_R_HH