emma (version 0.1-0)

ackley: Ackley test problem

Description

Generates the Ackley benchmark function. The Ackley function is a commonly used test problem for global optimization procedures.

Usage

ackley(x)

Arguments

x

A matrix containing the values of the input variables.

Value

Vector of the same length as x giving the values of the Ackley function.

References

http://www-optima.amp.i.kyoto-u.ac.jp/member/student/hedar/Hedar_files/TestGO_files/Page295.htm

Examples

x1 <- seq(-2, 2, length = 50)
x2 <- x1

x <- expand.grid(x1, x2)

z <- matrix(ackley(x),nrow = length(x1))

nrz <- nrow(z)
ncz <- ncol(z)
jet.colors <- colorRampPalette( c("red", "yellow") ) 
nbcol <- 100
color <- jet.colors(nbcol)
zfacet <- z[-1, -1] + z[-1, -ncz] + z[-nrz, -1] + z[-nrz, -ncz]
facetcol <- cut(zfacet, nbcol)

persp(x1, x2, z, col = color[facetcol], theta = 0, phi = 10, 
	expand = 1, xlab = "x1", ylab = "x2", zlab = "f(x1, x2)", 
	ticktype = "detailed")