Math addition transformer

[michalgromiec]

issue #69 - implementation of AdditionTransformer from mathematical transformation

[solegalli]

Hi @michalgromiec thank you again for the great work. Please see my comments. I also think we should change the name of the python script, to maybe mathematical_combination.py.

I think mathematical_transformers.py is too similar to the script variable_transformer.py, which applies math transformations variables per variables, and users may get confused.

Cheers
Sole

[solegalli]

Hi @michalgromiec thanks a lot for the amount of work. Could I also ask the following:

Because this is a new feature that adds functionality at the moment not present in Feature-engine we should also add a bit of information to the documentation. Could I also ask you to include the following files:

• nside the folder docs make a subfolder called mathematical_combination
• inside the mathematical_combination folder we need an index.rst and another rst file with the name of the transformer you just created where we add details to populate the dosctring of the transformer with sphinx, plus an example of how it can be used (code).
• in the doc/index.rst we need to update the index to include the mathematical combination functionality under the wrappers
• in the doc/index.rst, please add themathematical_combination folder to the toctree at the end.

Test that the docs run and build successfully.

Thanks a lot!

[solegalli]

@michalgromiec all done! Thank you!