Add the three-dimensional test function from Williams et al. (2006)

[damar-wicaksono]

The function was used in the metamodeling and sensitivity analysis exercises in ¹. The function reads (Section 2.3):

$$ \mathcal{M}(\boldsymbol{x}) = (x_1 + 1) \cos{(\pi x_2)} + 0 x_3, $$

where $X_i \sim \mathcal{U}(0, 1), I = 1, 2, 3$. Note that the third input variable is inert.

Footnotes

1. J. Gattiker, D. Higdon, S. Keller-McNulty, M. McKay, L. Moore, and B. Williams, “Combining experimental data and computer simulations, with an application to flyer plate experiments,” Bayesian Anal., vol. 1, no. 4, Dec. 2006, doi: 10.1214/06-BA125. ↩