Implement Elitism in Symbolic Regression

[Ethan Heavey]

Hi DEAP users!

I'm working to implement my first GP system using DEAP, and am struggling to get elitism working. I've got a .csv file containing x and y coordinates of points, and would like to find the function 'f' that, f(x) = y.

I've seen and tried to implement other posts in this forum (https://groups.google.com/g/deap-users/c/iannnLI2ncE) and (https://groups.google.com/g/deap-users/c/H6qSjra11GE) to no avail. I'm working with the "algorithms.eaMuPlusLambda" function but I'm really not sure if that's the right one to use. I was using eaSimple originally but the eaMuPlusLambda function seems to implement elitism (line 329 of https://github.com/DEAP/deap/blob/master/deap/algorithms.py) but I'm still getting results that vary wildly even though the data doesn't change. 

Any hints or direction you could provide would be much appreciated, the next step is to implement a strongly typed GP but I want to get the base GP system working as best I can first.

Thanks for taking the time to read this, hope to hear from you guys soon!