This is matlab implementation of some function
from python package [Strawberry Fields](https://strawberryfields.ai/)

They are handy for quantum optics mode calculations.


The initial conversion was done with Perplexity AI on 2024/11/19, but
it required a human intervention for some of the code.
Most notably xpxp_to_xxpp code was modified to match Matlab
treatment of everything as at least two dimensional matrix.