permute.h

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/*
 *  This file is a part of TiledArray.
 *  Copyright (C) 2016  Virginia Tech
 *
 *  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 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/>.
 *
 *  Justus Calvin
 *  Department of Chemistry, Virginia Tech
 *
 *  permute.h
 *  Jan 10, 2016
 *
 */

#ifndef TILEDARRAY_TILE_INTERFACE_PERMUTE_H__INCLUDED
#define TILEDARRAY_TILE_INTERFACE_PERMUTE_H__INCLUDED

#include "../type_traits.h"
#include "../tile_interface/cast.h"

namespace TiledArray {

  class Permutation;


  template <typename Arg>
  inline auto permute(const Arg& arg, const Permutation& perm)
  { return arg.permute(perm); }

  template <typename> struct permute_trait;

  namespace tile_interface {

    using TiledArray::permute;

    template <typename T>
    using result_of_permute_t = typename std::decay<
        decltype(permute(std::declval<T>(),
        std::declval<Permutation>()))>::type;

    template <typename Tile, typename Enabler = void>
    struct permute_trait {
      typedef Tile type;
    };

    template <typename Arg>
    struct permute_trait<Arg,
        typename std::enable_if<
            TiledArray::detail::is_type<result_of_permute_t<Arg> >::value
        >::type>
    {
      typedef result_of_permute_t<Arg> type;
    };

    template <typename Result, typename Arg, typename Enabler = void>
    class Permute {
    public:

      typedef Result result_type; 
      typedef Arg argument_type; 

      result_type operator()(const argument_type& arg,
          const Permutation& perm) const
      {
        using TiledArray::permute;
        return permute(arg, perm);
      }
    };

    template <typename Result, typename Arg>
    class Permute<Result, Arg,
        typename std::enable_if<
            ! std::is_same<Result, result_of_permute_t<Arg> >::value
        >::type> :
        public TiledArray::Cast<Result, result_of_permute_t<Arg> >
    {
    private:
      typedef TiledArray::Cast<Result, result_of_permute_t<Arg> > Cast_;
    public:

      typedef Result result_type; 
      typedef Arg argument_type; 

      result_type operator()(const argument_type& arg,
          const Permutation& perm) const
      {
        using TiledArray::permute;
        return Cast_::operator()(permute(arg, perm));
      }

    };

  } // namespace tile_interface



  template <typename Arg>
  struct permute_trait :
      public TiledArray::tile_interface::permute_trait<Arg>
  { };



  template <typename Result, typename Arg>
  class Permute : public TiledArray::tile_interface::Permute<Result, Arg> { };

} // namespace TiledArray

#endif // TILEDARRAY_TILE_INTERFACE_PERMUTE_H__INCLUDED