% Wilkinson's Function
% Range of initial points: 1 <= x <= 10
% Global minima: x=6.325654058491549
% f(x)=-443.6717047411253
% Coded by: Ali R. Alroomi | Last Update: 10 August 2015 | www.al-roomi.org
 
clear
clc
warning off
 
xmin=1;
xmax=10;
R=100000; % steps resolution
x=xmin:(xmax-xmin)/R:xmax;
 
for i=1:length(x)
    f(i)=0.000089248*x(i)-0.0218343*x(i).^2+0.998266*x(i).^3-1.6995*x(i).^4+0.2*x(i).^5;
end
 
plot(x,f,'r','LineWidth',2);grid;set(gca,'FontSize',12);
xlabel('x','FontName','Times','FontSize',20,'FontAngle','italic');
ylabel('f(x)','FontName','Times','FontSize',20,'FontAngle','italic');