Solved by KFrank in post #3 
              
              
                Hi Usman! 

Probably the most direct approach is to average the matrix with its 
transpose.  Here is an illustration for the 3-dimensional-tensor use 
case you mention: 
>>> torch.__version__
'1.7.1'
>>> t = torch.tensor ([[[1, 2, 3], [4, 5, 6], [7, 8, 9]], [[10, 20, 30], [40, 50, 60], [70, 80, 90]]…