t.   cumulative (bool) —
If cumulative is False, the single step transition matrix t-1->t is used. If cumulative is
True, the cumulative transition matrix 0->t is used.   Returns 
torch.FloatTensor of shape (batch size, num classes - 1, num latent pixels)
  
Each column of the returned matrix is a row of log probabilities of the complete probability
transition matrix.
When non cumulative, returns self.num_classes - 1 rows because the initial la