How to automatically block a path when training a multi-paths model with mini-batches

Hi everyone,

For example, I’m training a model for joint video and voice recognition with mini-batches, using RNN. The model is like this

                                                       -    Path 1 (Video RNN) 
                                                      /                                  \
Data (batches contains 3 videos)                                                        Fusing  ->  Result
                                                      \                                  /
                                                        -    Path 2 (Voice RNN) 

However, because some of the videos do not have voice information (no voice recorder), the input of the voice path is all 0s. But I still need to feed the network both the video and (an all-zero) voice data. It’s obvious that the all 0s input in Path 2 will harm the final result when fusing the two paths together. I’m wondering whether there is a way to block the voice path (Path 2) in training based on whether the voice information is available or not? Note that if the Path 2 is disabled, the voice feature will be assigned as all 0s during fusion instead of some random generated by the layers in Path 2 (as the response of an all 0 input vector). It is also important to mention that the network should support mini-batch as input.

Best regards,

Hi Yuhang

I think you can add a if statement in the forward() function. something like:

x1 = path1(...)
x2 = path2(...)
if voice:
    x =, x2)
    x =, Variable(torch.zeros(...,...)))

Thank you, I will try it !