toTypedList Class — pytorch Architecture

Source Code

aten/src/ATen/core/List_inl.h lines 55–69

template<class T>
List<T> toTypedList(impl::GenericList list) {
  // If there's other instances of the list (i.e. list.use_count() > 1), then we have to be invariant
  // because upcasting would allow people to add types into the new list that would break the old list.
  // However, if there aren't any other instances of this list (i.e. list.use_count() == 1), then we can
  // allow upcasting. This can be a perf improvement since we can cast List<T> to List<optional<T>>
  // without having to copy it. This is also used to provide backwards compatibility with some old models
  // that serialized the index arguments to aten::index, aten::index_put, aten::index_put_ and aten::index_put_impl_
  // as List<Tensor> before we changed that argument to be List<optional<Tensor>>. When deserializing, we
  // have list.use_count() == 1 and can deserialize the List<Tensor> directly as List<optional<Tensor>>.
  TORCH_CHECK(*list.impl_->elementType == *getTypePtr<T>()
    || (list.use_count() == 1 && list.impl_->elementType->isSubtypeOf(*getTypePtr<T>()))
    , "Tried to cast a List<", toString(*list.impl_->elementType), "> to a List<", toString(*getTypePtr<T>()), ">. Types mismatch.");
  return List<T>(std::move(list.impl_));
}