GitLab

* Change optical flow train.py function name from validate to evaluate so it is similar to other references

* Add --device as parameter and enable to run in non distributed mode

* Format with ufmt

* Fix unneccessary param and bug

* Enable saving the optimizer and scheduler on the checkpoint

* Fix bug when evaluate before resume and save or load model without ddp

* Fix case where --train-dataset is None
Co-authored-by: Nicolas Hug <nicolashug@fb.com>