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 * provided that the following conditions are met:
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#pragma once

#include <stdexcept>
#include "cutlass/cutlass.h"
#include "tools/util/reference/device/kernel/tensor_foreach.h"

namespace cutlass  {
namespace reference {
namespace host {

///////////////////////////////////////////////////////////////////////////////////////////////////

/// Defines several helpers
namespace detail {

/// Helper to perform for-each operation
template <typename Func, int Rank, int RankRemaining>
struct TensorForEachHelper {

  /// Index of the active rank
  static int const kActiveRank = Rank - RankRemaining - 1;

  /// Constructor for general rank
  TensorForEachHelper(
    Func &func,
    Coord<Rank> const &size,
    Coord<Rank> &coord) {

    for (int i = 0; i < size.at(kActiveRank); ++i) {
      coord[kActiveRank] = i;
      TensorForEachHelper<Func, Rank, RankRemaining - 1>(func, size, coord);
    }
  }
};

/// Helper to perform for-each operation
template <typename Func, int Rank>
struct TensorForEachHelper<Func, Rank, 0> {

  /// Index of the active rank
  static int const kActiveRank = Rank - 1;

  /// Constructor for fastest chaning rank
  TensorForEachHelper(
    Func &func,
    Coord<Rank> const &size,
    Coord<Rank> &coord) {

    for (int i = 0; i < size.at(kActiveRank); ++i) {
      coord[kActiveRank] = i;
      func(coord);
    }
  }
};

} // namespace detail

///////////////////////////////////////////////////////////////////////////////////////////////////

/// Iterates over the index space of a tensor
template <typename Func, int Rank, typename Params>
struct TensorForEach {

  /// Constructor performs the operation.
  TensorForEach(Coord<Rank> size, Params params = Params()) {

    Func func(params);
    Coord<Rank> coord;

    detail::TensorForEachHelper<Func, Rank, Rank - 1>(func, size, coord);
  }
};

///////////////////////////////////////////////////////////////////////////////////////////////////

} // namespace host
} // namespace reference
} // namespace cutlass