copperwiring:

preds = torch.argmax(output, dim=1) will give me the prediction values (or probabilties). Will I need to use a softmax or a sigmoid for thresholding?


This will give you the predicted class indices, no probabilities.
output should contain the raw logits. If you need to see probabilities, you should apply softmax on it.
However, you don’t need to use the softmax to get the most likely predicted class, as argmax(logits, 1) will yield the same result as argmax(softmax(logtis, 1) 1).
A threshold is not necessary for a multi-class prediction.