F.nll_loss(F.log_softmax(pred, -1), y_train) = F.cross_entropy(pred, y_train)
https://www.youtube.com/playlist?list=PLtmWHNX-gukKocXQOkQjuVxglSDYWsSh9
https://medium.com/the-artificial-impostor/notes-neural-language-model-with-pytorch-a8369ba80a5c
F.nll_loss(F.log_softmax(pred, -1), y_train) = F.cross_entropy(pred, y_train)
https://www.youtube.com/playlist?list=PLtmWHNX-gukKocXQOkQjuVxglSDYWsSh9
https://medium.com/the-artificial-impostor/notes-neural-language-model-with-pytorch-a8369ba80a5c