Well, this is an old code (i did it like 9 months ago and rescue now because i remember that mode collapse and want to compare with the new one). Actually, in that code, z_lat is a Variable, and if I pass .data everything works. However, if normalize() is expecting a torch.Variable that is what happens.
So for the current release I understand that .data is also bugged… Are you planning to take it out in future releases? It is a bit confusing. Can one copy a tensor using detach().data? Should that work?
Well, at least I have seen that aVAEs can suffer from mode collapse when linearly transforming the latent space… One can always learn something interesting even from a bug 
Thanks for your reply