Description

The fused optimizers (copied from Apex in #867) have a non-standard API that makes it annoying to swap with the vanilla PyTorch optimizers. This PR deprecates the set_grad_none kwarg in FusedAdam and FusedSGD in favor of a set_to_none kwarg in zero_grad, similar to the vanilla PyTorch API. I've also modified some of the constructor kwargs to be more consistent with PyTorch.

Closes #1453.

Type of change

• Documentation change (change only to the documentation, either a fix or a new content)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Infra/Build change
• Code refactoring

Changes

• Deprecate set_grad_none kwarg in FusedAdam and FusedSGD in favor of set_to_none kwarg in zero_grad
• Reorder kwargs in FusedAdam and FusedSGD constructors

Checklist:

• I have read and followed the contributing guidelines
• The functionality is complete
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes