train_vqa (and others) hanging when using multiprocessing

[george-larionov]

I'm trying to run this model as per the instructions and it keeps hanging, usually during or after optimizer.step() but sometimes in other places as well. I've found that completely removing the multiprocessing and just running train() on it's own get's rid of my problem (I'm using a p3.2xlarge AWS instance, so memory/processing power is not an issue).

I also found this page which appears to address a very similar issue with using the data loader which you are also using in your code, so I am wondering if this could be the root of the problem. I have downloaded and installed and deleted and reinstalled all the repositories and data and everything else numerous times so I am pretty certain the issue is not my fault. Thanks!