Criterion for selecting symbolic function in Symbolic_LANLayer.fix_symbolic()

[jkim621]

Hello! I'm wondering how did authors select the criterion of fixing symbolic function of activation node as correlation coefficient. In Symbolic_LANLayer.fix_symbolic() method, I found that r2 is calculated by utils.fit_params() function, and fit_params() function derives r2 value between activation node and symbolic function using correlation between them. I think that it is more appropriate to use r2 as coefficient of determination(R^2) value as r2 variable in code, so I'm wondering why authors select correlation as r2 between two functions. Is there any reason?

Thank you for any opinion for the question!

[KindXiaoming]

just a random choice tbh :)