Pad a sparse output layer about returnn HOT 2 CLOSED

What exactly is the layer "output1" output (of type Data)? You will see that when you enable debug_print_layer_output_template = True in the config. So it will say something like Data(..., dim=10017, sparse=True), right? So, can you verify, it is really saying sparse=True there?

PadLayer can not work with sparse input. I also don't quite understand how you think that it is supposed to work. Sparse means that the data are just integers with the label indices. The dim flag is just a hint that all integers will be within [0, .., dim - 1].

Maybe you just want to enforce that the output has an overridden dim flag? ReinterpretDataLayer might be what you need here, by using increase_sparse_dim.

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Thanks @albertz , this is exactly what I was looking for. It works as expected now, I think :)

Yeah, the layer was really sparse and I could verify that by doing what you suggested.

I wanted to make two layers of different sizes interact with each other and that's why I had to add another layer between them to correct the mismatch.

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