torch.acos
torch.acos(input, *, out=None) -> Tensor
Computes the inverse cosine of each element in "input".
  \text{out}_{i} = \cos^{-1}(\text{input}_{i})

Parameters:
      input (Tensor) -- the input tensor.
Keyword Arguments:
      out (Tensor, optional) -- the output tensor.
Example:
  >>> a = torch.randn(4)
  >>> a
  tensor([ 0.3348, -0.5889,  0.2005, -0.1584])
  >>> torch.acos(a)
  tensor([ 1.2294,  2.2004,  1.3690,  1.7298])
