torch.triu
torch.triu(input, diagonal=0, *, out=None) -> Tensor
Returns the upper triangular part of a matrix (2-D tensor) or batch
   of matrices "input", the other elements of the result tensor "out"
   are set to 0.
The upper triangular part of the matrix is defined as the elements
   on and above the diagonal.
The argument "diagonal" controls which diagonal to consider. If
   "diagonal" = 0, all elements on and above the main diagonal are
   retained. A positive value excludes just as many diagonals above
   the main diagonal, and similarly a negative value includes just as
   many diagonals below the main diagonal. The main diagonal are the
   set of indices \lbrace (i, i) \rbrace for i \in [0, \min{d_{1},
   d_{2}} - 1] where d_{1}, d_{2} are the dimensions of the matrix.
Parameters:
      * input (Tensor) -- the input tensor.
  * **diagonal** (*int**, **optional*) -- the diagonal to consider

Keyword Arguments: