concat or sum? about pytorch-vqa

[Cyanogenoid]

Concatenating two vectors v and q followed by a linear projection W is the same as projecting v and q individually with W_v and W_q, then adding them. Does this picture make it clearer?

[ozancaglayan]

yes i know about this, in fact i thought about this before posting. So your v (->512) and q (->512) transformations that you apply before the x_conv are the ones that replaces the concat+conv, then?
I was just not sure about the non-lins and the interplay of Conv about this equivalence of concat vs sum in this case.

[Cyanogenoid]

Correct. In this case it is exactly equivalent, there are no nonlinearities affecting this and the conv is a 1x1 convolution.

[ozancaglayan]

thanks!