powered by
(x1,x2) -> x1 + x2 + x1*x2
fun_test2d_ranjan(x)
2-dimensional input (or matrix which lines or such inputs)
Image of x by fun_test2d_ranjan
Ranjan, P., Bingham, D., Michailidis, G.: Sequential experiment design for contour estimation from complex computer codes. Technometrics 50(4), 527-541 (2008)