Well, that´s very clever, in fact I programmed my train and test loop based on what I´ve seen in the docs and examples where they compute metrics in each batch loop.
But reading again and thinking about what´s stated in the docs, the phrase “The metric is only proper defined…” I think that asks my question. If in that situation the metric wouldn’t give any reasonable result because it’s not defined to give result in this case, I think I should just skip these results.
But for sure I will consider what you proposed for future implementations.