BACCO (version 1.1-4)

hpa.fun.toy: Toy example of a hyperparameter object creation function

Description

Creates a hyperparameter object from a vector of length 19. Intended as a toy example to be modified for real-world cases.

Usage

hpa.fun.toy(x)

Arguments

x

Vector of length 19 that specifies the correlation scales

Value

• sigmas
  The four sigmas corresponding to the four levels
• B
  The four B matrices corresponding to the four levels
• rhos
  The three (sic) matrices corresponding to levels 1-3

Details

Elements 1-4 of x specify the sigmas for each of the four levels in the toy example. Elements 5-7 specify the correlation scales for level 1, elements 8-10 the scales for level 2, and so on.

Internal function pdm.maker() shows how the B matrix is obtained from the various elements of input argument x. Note how, in this simple example, the B matrices are diagonal, but generalizing to non-diagonal matrices should be straightforward (if you can guarantee that they remain positive definite).

References

M. C. Kennedy and A. O'Hagan 2000. Predicting the output from a complex computer code when fast approximations are available Biometrika, 87(1): pp1-13

Examples

hpa.fun.toy(1:19)