The function was introduced in Currin et al. (1991)[^Currin] as a test function for a metamodeling exercise. The function is a two-dimensional polynomial function defined as follows:
where $\boldsymbol{x} = \{ x_1, x_2 \}$ is the vector of input variables modeled as an independent uniform random vector in $[0, 1]^2$.
[^Currin]: C. Currin, T. Mitchell, M. Morris, and D. Ylvisaker, “Bayesian Prediction of Deterministic Functions, with Applications to the Design and Analysis of Computer Experiments,” Journal of the American Statistical Association, vol. 86, no. 416, pp. 953–963, 1991, doi: 10.2307/2290511.
The function was introduced in Currin et al. (1991)[^Currin] as a test function for a metamodeling exercise. The function is a two-dimensional polynomial function defined as follows:
$$ \mathcal{M}(\boldsymbol{x}) = 4.90 + 21.15 x_1 - 2.17 x_2 - 15.88 x_1^2 - 1.38 x_2^2 - 5.26 x_1 x_2, $$
where $\boldsymbol{x} = \{ x_1, x_2 \}$ is the vector of input variables modeled as an independent uniform random vector in $[0, 1]^2$.
[^Currin]: C. Currin, T. Mitchell, M. Morris, and D. Ylvisaker, “Bayesian Prediction of Deterministic Functions, with Applications to the Design and Analysis of Computer Experiments,” Journal of the American Statistical Association, vol. 86, no. 416, pp. 953–963, 1991, doi: 10.2307/2290511.