use APEX DistributedDataParallel if use_amp is None

[ShoufaChen]

https://github.com/rwightman/pytorch-image-models/blob/3d9c23af879283e80c2c208786d5613351ca040b/train.py#L454

Hi, I found that if we don't activate amp but the apex is installed in our env, it will choose the ApexDDP by default.

I was wondering is it a best choice or did I miss something?

Thanks in advance.

[rwightman]

@ShoufaChen you are right, that's not the best choice these days, I almost always use amp (which defaults to native) so this isn't an issue, I'll make a note to fix

[ShoufaChen]

Hi, @rwightman

Thanks for your reply. I pull a request #882 for this issue.

[rwightman]

@ShoufaChen thanks, merged