DiceKriging (version 1.6.0)

goldsteinPrice: 2D test function

Description

Goldstein price 2-dimensional test function.

Usage

goldsteinPrice(x)

Arguments

x

a 2-dimensional vector specifying the location where the function is to be evaluated.

Value

A real number equal to the Goldstein price function values at x

Details

The Goldstein price function is usually defined over the domain [-2,-2] x [2, 2]. Here, the function is adapted to the domain [0,1] x [0,1]. It has 1 global minimum : x1 = c(0.5, 0.25)

Examples

# NOT RUN {
n.grid <- 20
x.grid <- y.grid <- seq(0,1,length=n.grid)
design.grid <- expand.grid(x.grid, y.grid)
response.grid <- apply(design.grid, 1, goldsteinPrice)
z.grid <- matrix(response.grid, n.grid, n.grid)
contour(x.grid, y.grid, z.grid, 40)
x1 = c(0.5, 0.25)
points(t(x1), pch=19, col="red")
title("Fonction de Goldstein price")
# }