NCE accuracy calculation

[JaejinCho]

Hello @jefflai108,

I think the accuracy also should have its denominator as batch*self.timestep at https://github.com/jefflai108/Contrastive-Predictive-Coding-PyTorch/blob/a9dab4e759aaa68dce1b1ada46a8035076ba3296/src/model/model.py#L320

Possibly for other models too although I did not check them.

[colinator]

Yes, and it should be correct += I believe, just above there...