Add inference mode python bindings and tests (#58045)
Summary:
Fixes https://github.com/pytorch/pytorch/issues/56608
- Adds binding to the `c10::InferenceMode` RAII class in `torch._C._autograd.InferenceMode` through pybind. Also binds the `torch.is_inference_mode` function.
- Adds context manager `torch.inference_mode` to manage an instance of `c10::InferenceMode` (global). Implemented in `torch.autograd.grad_mode.py` to reuse the `_DecoratorContextManager` class.
- Adds some tests based on those linked in the issue + several more for just the context manager
Issues/todos (not necessarily for this PR):
- Improve short inference mode description
- Small example
- Improved testing since there is no direct way of checking TLS/dispatch keys
-
Pull Request resolved: https://github.com/pytorch/pytorch/pull/58045
Reviewed By: agolynski
Differential Revision: D28390595
Pulled By: soulitzer
fbshipit-source-id: ae98fa036c6a2cf7f56e0fd4c352ff804904752c
