% OBJECTIVE FUNCTION
f = @(x) (x(:,1).^4 - 16*x(:,1).^2 + 5*x(:,1) + x(:,2).^4 - 16*x(:,2).^2 + 5*x(:,2))/2

% OPTIMIZATION SETTINGS
o = struct	% initializing struct
o.lb = -5	% lower bounds
o.ub = 5	% upper bounds

% GRAPHIC REPRESENTATION
[x,y] = meshgrid(o.lb:0.5:o.ub)
surf(x,y,f([x(:),y(:)]))

% OPTIMIZATION 
rng(0)	% for tractability 
x0 = [3,3]	% initial guess 
[xmin,fmin,info] = fminsearch(f,x0,o)	% running minimization  

% ANIMATION
% Uncomment the following code to generate animation % 
% rng(0)
% x0 = [3,3]
% [~,~,info] = fminsearch(f,x0,o)
% info.sol = [-2.903534 -2.903534 -78.332]	% solution 
% info.animate = true	% plot animation 
% info.animfreq = 5	% frame frequency 
% info.np = 20	% number of points for meshgrid 
% optimview('fminsearch',info)