# exp2d

0th

Percentile

##### 2-d Exponential Data

A 2-dimensional data set that can be used to validate non-stationary models.

Keywords
datasets, datagen
##### Usage
data(exp2d)
##### Details

The true response is evaluated as $$Z(X)=x_1 * \exp(x_1^2-x_2^2).$$ Zero-mean normal noise with sd=0.001 has been added to the true response

##### Note

This data is used in the examples of the functions listed below in the “See Also” section via the exp2d.rand function

##### Format

A data frame with 441 observations on the following 4 variables.

X1

Numeric vector describing the first dimension of X inputs

X2

Numeric vector describing the second dimension of X inputs

Z

Numeric vector describing the response Z(X)+N(0,sd=0.001)

Ztrue

Numeric vector describing the true response Z(X), without noise

##### References

Gramacy, R. B. (2020) Surrogates: Gaussian Process Modeling, Design and Optimization for the Applied Sciences. Boca Raton, Florida: Chapman Hall/CRC. https://bobby.gramacy.com/surrogates/

Gramacy, R. B. (2007). tgp: An R Package for Bayesian Nonstationary, Semiparametric Nonlinear Regression and Design by Treed Gaussian Process Models. Journal of Statistical Software, 19(9). https://www.jstatsoft.org/v19/i09

Robert B. Gramacy, Matthew Taddy (2010). Categorical Inputs, Sensitivity Analysis, Optimization and Importance Tempering with tgp Version 2, an R Package for Treed Gaussian Process Models. Journal of Statistical Software, 33(6), 1--48. https://www.jstatsoft.org/v33/i06/.

Gramacy, R. B., Lee, H. K. H. (2008). Bayesian treed Gaussian process models with an application to computer modeling. Journal of the American Statistical Association, 103(483), pp. 1119-1130. Also available as ArXiv article 0710.4536 https://arxiv.org/abs/0710.4536

https://bobby.gramacy.com/r_packages/tgp/

exp2d.rand, exp2d.Z, btgp, and other b* functions