How to apply a element wise cross_entropy/nll loss to a 3D matrix?

[charan_Vjy]

The answer has been provided here.

Cross entropy loss for sentence classification

I have a tensor in shape of [ #batch_size, #n_sentences, #scores]. #scores are calculated for each fixed class. To clarify, suppose we have batch size of 1, with 31 sentences and 5 classes that sentences have been assigned to. So the tensor would have the shape of [1, 31, 5]. Now as my target (i.e., true section labels of each 31 sentences), I’d have a tensor in shape of [1, 31]. containing 31 numbers in the range of 0-4. I’m wondering how I can compute cross entropy loss for these (inputs and t…