Branin-Hoo 2-dimensional test function.
branin(x)
a 2-dimensional vector specifying the location where the function is to be evaluated.
A real number equal to the Branin-Hoo function values at x
The Branin-Hoo function is defined here over [0,1] x [0,1], instead of [-5,0] x [10,15] as usual. It has 3 global minima : x1 = c(0.9616520, 0.15); x2 = c(0.1238946, 0.8166644); x3 = c(0.5427730, 0.15)
# 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, branin) z.grid <- matrix(response.grid, n.grid, n.grid) contour(x.grid,y.grid,z.grid,40) x1 = c(0.9616520, 0.15); x2 = c(0.1238946, 0.8166644); x3 = c(0.5427730, 0.15) points(rbind(t(x1), t(x2), t(x3)), pch=19, col="red") title("Fonction de Branin") # }