torch.log
torch.log(input, *, out=None) -> Tensor
Returns a new tensor with the natural logarithm of the elements of
   "input".
  y_{i} = \log_{e} (x_{i})

Parameters:
      input (Tensor) -- the input tensor.
Keyword Arguments:
      out (Tensor, optional) -- the output tensor.
Example:
  >>> a = torch.rand(5) * 5
  >>> a
  tensor([4.7767, 4.3234, 1.2156, 0.2411, 4.5739])
  >>> torch.log(a)
  tensor([ 1.5637,  1.4640,  0.1952, -1.4226,  1.5204])
