Create two propagation functions for an already built project

Hi. I have developed a structure called simulation region where i simulate propagation of signals and i wanted to improve it with 2 functions, one that calculates the max propagation distance before i get alias, and one that improves the function that i have right now to do free propagation. The second new function would have to adapt the simulation region during the propagation so i can have non-aliased long propagations :)
Just these 2 functions, i will provide you the simulation region, books for references for theory if needed, my already tries for the two functions and all my knowledge!