pytorch

f227530c - Clean up named tensor `propagate_names` API (#29239)

Clean up named tensor `propagate_names` API (#29239) Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/29239 There were a few main changes, summarized below. Rename `propagate_names` ---------------------------------------------- There are two main APIs now, `propagate_names_if_nonempty(Tensor&, ArrayRef<Dimname>)` and `propagate_names(Tensor&, ArrayRef<Dimname>)` The former propagates names if they are not empty and the latter unconditionally tries to propagate names. `names` can be empty if name inference did not occur (see the next section). Removed usages of `optional` in name inference ---------------------------------------------- Previously, we used `optional<ArrayRef<Dimname>>` and `optional<vector<Dimname>>`. `nullopt` represens that no name inference happened. The problem with this is that these types are not implicitly convertible to each other and dealing with them is painful as a result (users have to manually unwrap `optional<vector>` and convert to `optional<arrayref>`. To fix this, I rewrote most named inference functions to use an empty array as an indicator value: - If an array is empty, then no name inference occured - If an array is not empty, then name inference occured. Removed `vector<Dimname>&&` overloads ---------------------------------------------- These were originally meant for efficiency: instead of copying a vector of names we could move it directly inside the tensor and replace the old names. However, looking around the code base, we do copies for `IntArrayRef` for sizes and strides instead of optimizing them, so the perf gain is probably not critical. I removed `vector<Dimname>&&` overloads to stop optimizing prematurely. Furthermore, one potential design for a faster named inference api is to construct names directly on a tensor's names object; in this design there is also no `vector<Dimname>&&` overload. Plans ---------------------------------------------- After this PR I'll keep attempting to cleaning up `propagate_names` functions. There are a lot of `propagate_names_for_{blah}` functions that exist that probably don't need to. Test Plan: - `python test/test_namedtensor.py -v` Differential Revision: D18350090 Pulled By: zou3519 fbshipit-source-id: eb5dd6cbd2d4f1838431db5edbdb207204c5791d