Figure 7.

Exact response surface $S=\mathbb{E}[Y(\mathbf{\text{x}};\xi )]$ and co-kriging predictor constructed using four levels of fidelity: 80 S₁₁ points (f_c(x;ξ), SG-L2), 40 S₁₂ points (f_c(x;ξ), SG-L5), 10 S₂₁ points (f_e(x;ξ), SG-L2) and five S₂₂ points (f_e(x;ξ), SG-L5). The inset plot shows the point-wise variance of the co-kriging predictor. (Online version in colour.)