A data piece that might be helpful:
data:
Variable containing:
( 0  ,.,.) = 
  0.0417 -0.0041 -0.0519  ...  -0.0086  0.0407 -0.0095
  0.0733 -0.0780 -0.0431  ...  -0.0061  0.0458  0.0193
  0.0938 -0.0610 -0.0333  ...  -0.0049  0.0135  0.0047
           ...             ⋱             ...          
  0.0000  0.0000  0.0000  ...   0.0000  0.0000  0.0000
  0.0000  0.0000  0.0000  ...   0.0000  0.0000  0.0000
  0.0000  0.0000  0.0000  ...   0.0000  0.0000  0.0000

( 1  ,.,.) = 
  0.0657 -0.0431  0.0004  ...  -0.0016  0.0423 -0.0068
  0.0916 -0.0649  0.0253  ...   0.0122  0.0777 -0.0116
  0.1211 -0.0619  0.0082  ...   0.0020  0.0683  0.0131
           ...             ⋱             ...          
  0.0000  0.0000  0.0000  ...   0.0000  0.0000  0.0000
  0.0000  0.0000  0.0000  ...   0.0000  0.0000  0.0000
  0.0000  0.0000  0.0000  ...   0.0000  0.0000  0.0000
...
[torch.cuda.FloatTensor of size 64x20x1024 (GPU 0)]

lens:
Variable containing:
 17
 13
  7
 13
 16
 11
  6
  3
  8
  6
...
[torch.cuda.LongTensor of size 64 (GPU 0)]