“…The first step is the function set Φ definition. In the modified hGP, the Φ set has two subsets for the arithmetic and mathematical functions, Φ and Φ , respectively, [18]. So, Φ = {Φ , Φ }, where Φ = {+, −, * , /} a nd Φ = {exp, log, sin, cos, Logistic, Gompertz I, Gompertz II, Bass, Bi-Logistic, LogInLog}.…”