Thx ptrblck!
The target is a binary vector, for example, [1, 0, 0, 0, 1, 0, 1, 1,...,0] (length 64).
I think it is possible to use rounding on the final outputs to force them to either 0 or 1.
So, I will try sigmoid + MSELoss.
However, any alternatives to using the sigmoid?