x (number or np.ndarray or Tensor or Pwc or Stf) – The object whose natural logarithm you want to calculate, \(x\). For numbers, arrays,
and tensors, the object is converted to a tensor and then the operation is applied. For
functions of time (Pwcs and Stfs), the composition of the operation with the function
is computed (that is, the operation is applied to the function values).