torch.tanh
torch.tanh(input, *, out=None) -> Tensor
Returns a new tensor with the hyperbolic tangent of the elements of
   "input".
  \text{out}_{i} = \tanh(\text{input}_{i})

Parameters:
      input (Tensor) -- the input tensor.
Keyword Arguments:
      out (Tensor, optional) -- the output tensor.
Example:
  >>> a = torch.randn(4)
  >>> a
  tensor([ 0.8986, -0.7279,  1.1745,  0.2611])
  >>> torch.tanh(a)
  tensor([ 0.7156, -0.6218,  0.8257,  0.2553])
