dropping output units rather than connections

[lzamparo]

Hi,

I think you've got a bug in your implementation: you're applying the dropout mask to output units rather than elements of your weight matrices, which is what the original version of dropout is intended to do. This means that you're dropping out bias units randomly, which might disrupt the model averaging interpretation of dropout.

I'm not sure if you intended to do this, but if not, you should reconsider having _droput_from_layer apply a mask directly to the Ws, and then computing the layer output (see eqn's 2.3 -- 2.6 of Nitish's thesis)

[lzamparo]

Ah, nevermind. I didn't read the model specification closely myself.