torch.abs
torch.abs(input, *, out=None) -> Tensor
Computes the absolute value of each element in "input".
  \text{out}_{i} = |\text{input}_{i}|

Parameters:
      input (Tensor) -- the input tensor.
Keyword Arguments:
      out (Tensor, optional) -- the output tensor.
Example:
  >>> torch.abs(torch.tensor([-1, -2, 3]))
  tensor([ 1,  2,  3])
