Goldstein-Price
Problem definition
Objective function
f = @(x) (1+((x(:,1) + x(:,2) + 1).^2).*(19 - 14*x(:,1) + ... 3*x(:,1).^2 - 14*x(:,2) + 6*x(:,1).*x(:,2) + ... 3*x(:,2).^2)).*(30 + ((2*x(:,1) - 3*x(:,2)).^2).* (18 - 32*x(:,1)+ ... 12*x(:,1).^2 + 48*x(:,2) - 36*x(:,1).*x(:,2) + 27*x(:,2).^2))
Optimization settings
o = struct% initializing struct
o.d = 2% dimension of decision variable
o.lb = -2% lower bounds
o.ub = 2% upper bounds
Graphic representation
[x,y] = meshgrid(o.lb:0.4:o.ub) surf(x,y,f([x(:),y(:)]))
Problem properties
convexity | smoothness | minimum |
0 | ∞ | f(0,-1) = 3 |
Optimization example with ga
Optimization
rng(0)% for tractability
[xmin,fmin,popPos,popCost] = ga(f,o)% running minimization
Animation
rng(0) [~,~,~,~,info] = ga(f,o) info.sol = [0 -1 3]% solution
info.animate = true% plot animation
info.animfreq = 2% frame frequency
optimview('ga',info)
References
[1] A. A. Goldstein, J. F. Price, "On Descent from Local Minima", Mathematics and
Computation, vol. 25, no. 115, pp. 569-574, 1971