pytorch

8195961f - Revert D19730209: [pytorch][PR] Issue a warning when using zero_grad in DataParallel

Revert D19730209: [pytorch][PR] Issue a warning when using zero_grad in DataParallel Test Plan: revert-hammer Differential Revision: D19730209 Original commit changeset: cb9b2cb0c2e0 fbshipit-source-id: 5bf53ea3c37a7ed2411a2acc34e40d07eff144c9