This function is a polynomial in two dimensions, with terms up to degree 5. It is nonlinear, and it is smooth despite being complex, which is common for computer experiment functions (Lim et al., 2002 ...

Polynomial and special function theory remains a vibrant area of mathematical research, interweaving classical algebra with advanced analysis. At its core, the study concerns algebraic expressions ...

In particular, using polynomial regression typically requires a manual choice of the polynomial's degree, trading off between function accuracy and computational and memory efficiency. Polynomial ...