pytorch

0831984e - [Resubmission][Gradient Compression] Refactor default_hooks.py and powerSGD_hook.py by creating a util function that make a vanilla allreduce future (#51400)

[Resubmission][Gradient Compression] Refactor default_hooks.py and powerSGD_hook.py by creating a util function that make a vanilla allreduce future (#51400) Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/51400 Resubmission of #51094 Address https://github.com/pytorch/pytorch/pull/50973#discussion_r564229818 Original PR issue: Investigate Applying PowerSGD to Communication Hook for Gradient Compression #47202 ghstack-source-id: 120725690 Test Plan: buck test mode/dev-nosan caffe2/test/distributed:c10d -- test_powerSGD_ddp_comm_hook_nccl buck test mode/dev-nosan caffe2/test/distributed:c10d -- test_default_ddp_comm_hooks_nccl Reviewed By: rohan-varma Differential Revision: D26162333 fbshipit-source-id: ccc2eae5383a23673e00d61cb5570fb8bf749cd0