Add averaging operator to postprocessing

[CharlesC30]

Eli's next request is to add an operator to postprocessing for averaging data from multiple aimmdb entries. This operator should take an arbitrary number of entries as input and return a new entry with the averaged data, and metadata that points to the original unaveraged data.

@x94carbone I noticed all the currently defined operators use the UnaryOperator class. Is there any abstraction defined for operators that take multiple inputs?

[matthewcarbone]

@CharlesC30

I noticed all the currently defined operators use the UnaryOperator class. Is there any abstraction defined for operators that take multiple inputs?

Nope! We need to make one 👍

[CharlesC30]

@x94carbone I came up with this MultiOperator abstraction by modifying the UnaryOperator class. I am still working on the averaging operator itself but let me know if this looks alright so far. The one thing I am wondering is if this should also be able to operate on the Node class.

https://github.com/CharlesC30/aimmdb/blob/3664eaa08f9e876dd1d947e06157a5f2977a63b7/aimmdb/postprocessing/operations.py#L105-L163

[matthewcarbone]

@CharlesC30 great, thank you! Can you open a PR for this? We can discuss there. Totally fine if it's still a WIP.

[CharlesC30]

@x94carbone sure! I just created the PR. Not sure why but it included several commits from when I was working on the NormalizeLarch scheme, so just the most recent few commits are related to this.