a 2-dimensional vector specifying the location where the function
is to be evaluated.
Value
A real number equal to the goldsteinprice function values at
x
Details
The goldsteinprice (standardized version) function is defined over the
domain [0,1]^2. It has 1 global minimizer : x* = c(0.5, 0.25), with
minimum f(x*) = -3.129172, and 3 local minima x*,2 = c(0.35, 0.4), x*,3 =
c(0.95, 0.55), x*,4 = c(0.8 , 0.7), with respective minima f(x*,2) =
-2.180396, f(x*,3) = -1.756143, f(x*,4) = -0.807367.