constants.hpp

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/*
  Copyright (C) 2017 Marcus N Campbell Bannerman <[email protected]>
                2015 Severin Strobl <[email protected]>

  This file is part of stator.

  stator 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.

  stator 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 stator. If not, see <http://www.gnu.org/licenses/>.
*/

#pragma once

// C++
#include <ratio>
#include <type_traits>

namespace stator {

  template<typename Scalar,
           typename = typename std::is_floating_point<Scalar>::type>
  struct constant {

    static inline Scalar k() {
      return Scalar(1.3806488e-23);
    }
    
    static inline Scalar pi() {
      return Scalar(3.1415926535897932384626433832795029L);                    
    }

    static inline Scalar avogadro() {
      return Scalar(6.02214129e23);
    }

    static inline Scalar R() {
      return avogadro() * k();
    }

    static inline Scalar e() {
      return Scalar(2.7182818284590452353602874713526624L);
    }
  };

  struct constant_ratio {
    typedef std::ratio<47627751, 15160384> pi; 

    typedef std::ratio<28245729, 10391023> e; 
  };
} // namespace stator