Function recast

include/cute/tensor_impl.hpp:757–783

template <class NewType_, class Tensor>
CUTE_HOST_DEVICE constexpr
auto
recast(Tensor&& tensor)
{
  using OldType = typename remove_cvref_t<Tensor>::element_type;
  using NewType = copy_cv_t<OldType, NewType_>;

  if constexpr (is_same<NewType, OldType>::value) {
    return make_tensor(static_cast<Tensor&&>(tensor).data(), tensor.layout());
  } else {
    auto old_layout = tensor.layout();
    auto new_layout = recast_layout<OldType,NewType>(old_layout);

    // If this is an upcast of a normal Layout with static negative strides, then offset as well
    if constexpr (sizeof(OldType) < sizeof(NewType) && not is_composed_layout<decltype(old_layout)>::value) {
      auto shape_diff = transform(flatten(old_layout.shape()), flatten(new_layout.shape()), minus{});
      auto extent_diff = transform(shape_diff, flatten(old_layout.stride()), multiplies{});
      auto offset = fold(extent_diff, Int<0>{}, [](auto const& i, auto const& a) { return i + cute::min(a,Int<0>{}); });

      return make_tensor(recast_ptr<NewType>(static_cast<Tensor&&>(tensor).data() + offset), new_layout);
    } else {
      return make_tensor(recast_ptr<NewType>(static_cast<Tensor&&>(tensor).data()         ), new_layout);
    }
  }

  CUTE_GCC_UNREACHABLE;
}

//
// max_common_vector