pytorch

4f4c69b1 - Make set_grad_accumulator private (friend class SavedVariable) (#27666)

Make set_grad_accumulator private (friend class SavedVariable) (#27666) Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/27666 Signed-off-by: Edward Z. Yang <ezyang@fb.com> Test Plan: Imported from OSS Differential Revision: D17886544 Pulled By: ezyang fbshipit-source-id: b9ff845cb1e5ec6f7cb4f2fa171403d555014248