torch.Tensor.fill_diagonal_
Tensor.fill_diagonal_(fill_value, wrap=False) -> Tensor
Fill the main diagonal of a tensor that has at least 2-dimensions.
   When dims>2, all dimensions of input must be of equal length. This
   function modifies the input tensor in-place, and returns the input
   tensor.
Parameters:
      * fill_value (Scalar) -- the fill value
  * **wrap** (*bool*) -- the diagonal 'wrapped' after N columns
    for tall matrices.

Example:
  >>> a = torch.zeros(3, 3)
  >>> a.fill_diagonal_(5)
  tensor([[5., 0., 0.],
          [0., 5., 0.],
          [0., 0., 5.]])
  >>> b = torch.zeros(7, 3)
  >>> b.fill_diagonal_(5)
  tensor([[5., 0., 0.],
          [0., 5., 0.],
          [0., 0., 5.],
          [0., 0., 0.],
          [0., 0., 0.],
          [0., 0., 0.],
          [0., 0., 0.]])
  >>> c = torch.zeros(7, 3)
  >>> c.fill_diagonal_(5, wrap=True)
  tensor([[5., 0., 0.],
