Miscellaneous

Elementwise transforms

signal.apply()

signal.apply(function)

Apply a function to each element of the signal.

• Parameters: function – The name of the function to apply. A non-exhaustive list of standard function transform is: log (logarithm), exp (exponentiation), sqrt (square root), abs (absolute value), tanh (hyperbolic tangent).

A use case for transforming data is to get better properties when creating a model. In many cases, a model performs better if the data has been transformed with the logarithm before estimating the model. Here is an example on how to transform the signal:

US_CivilianUnemploymentRate_Monthly.apply('log')

It is also possible to do this in a modelling context. Then doing something like this can work:

predict(US_CivilianUnemploymentRate_Monthly.apply('log')).apply('exp')

We apply “exp” in the end to transform the predictions back to the original scale.