Following the example from the docs I am trying to solve a problem where the padding is inconsistent rather than at the end of the tensor for each batch (in other words, no pun intended, I have a left-censored and right-censored problem across my batches):
 # Data structure example from docs
seq = torch.tensor([[1,2,0], [3,0,0], [4,5,6]])
 # Data structure of my problem
inconsistent_seq = torch.tensor([[1,2,0], [0,3,0], [0,5,6]])

lens = ...?
packed = pack_padded_sequence(seq, lens, batch_first=True, enforce_sorted=False)

How can I solve the problem of masking these padded 0’s when running them through an LSTM using (preferably) PyTorch functionality?