A+ A A-

I. Mathematical Expression:

$$f(X)=\left(x^2_1+x^2_2-2\right)^2+\left(x^2_1-x^2_2-1\right)^2$$

where:

\(\bullet\) \(-3\leq x_i\leq 4\) , \(i=1,2\)

\(\bullet\) It has four global minimum: \(f_{min}(X^*)=0\)

\(\bullet\) \(x^*_i=(\pm\sqrt{1.5},\pm\sqrt{0.5})\)

 

II. Citation Policy:

If you publish material based on databases obtained from this repository, then, in your acknowledgments, please note the assistance you received by using this repository. This will help others to obtain the same data sets and replicate your experiments. We suggest the following pseudo-APA reference format for referring to this repository:

Ali R. Al-Roomi (2015). Unconstrained Single-Objective Benchmark Functions Repository [https://www.al-roomi.org/benchmarks/unconstrained]. Halifax, Nova Scotia, Canada: Dalhousie University, Electrical and Computer Engineering.

Here is a BiBTeX citation as well:

@MISC{Al-Roomi2015,
author = {Ali R. Al-Roomi},
title = {{Unconstrained Single-Objective Benchmark Functions Repository}},
year = {2015},
address = {Halifax, Nova Scotia, Canada},
institution = {Dalhousie University, Electrical and Computer Engineering},
url = {https://www.al-roomi.org/benchmarks/unconstrained}
}

 

III. 2&3D-Plots:

 

IV. Controllable 3D Model:

- In case you want to adjust the rendering mode, camera position, background color or/and 3D measurement tool, please check the following link

- In case you face any problem to run this model on your internet browser (it does not work on mobile phones), please check the following link

 

V. MATLAB M-File:

% Kearfott's Function
% Range of initial points: -3 <= xj <= 4 , j=1,2
% It has 4 global minimum: (x1,x2)= (+-sqrt(1.5),+-sqrt(0.5))
% f(x1,x2)=0
% Coded by: Ali R. Alroomi | Last Update: 24 March 2015 | www.al-roomi.org

clear
clc
warning off

x1min=-3;
x1max=4;
x2min=-3;
x2max=4;
R=1500; % steps resolution
x1=x1min:(x1max-x1min)/R:x1max;
x2=x2min:(x2max-x2min)/R:x2max;
   
for j=1:length(x1)
   
    for i=1:length(x2)
        f(i)=((x1(j).^2+x2(i).^2-2).^2)+((x1(j).^2-x2(i).^2-1).^2);
    end
       
    f_tot(j,:)=f;

end

figure(1)
meshc(x1,x2,f_tot);colorbar;set(gca,'FontSize',12);
xlabel('x_2','FontName','Times','FontSize',20,'FontAngle','italic');
set(get(gca,'xlabel'),'rotation',25,'VerticalAlignment','bottom');
ylabel('x_1','FontName','Times','FontSize',20,'FontAngle','italic');
set(get(gca,'ylabel'),'rotation',-25,'VerticalAlignment','bottom');
zlabel('f(X)','FontName','Times','FontSize',20,'FontAngle','italic');
title('3D View','FontName','Times','FontSize',24,'FontWeight','bold');

figure(2)
mesh(x1,x2,f_tot);view(0,90);colorbar;set(gca,'FontSize',12);
xlabel('x_2','FontName','Times','FontSize',20,'FontAngle','italic');
ylabel('x_1','FontName','Times','FontSize',20,'FontAngle','italic');
zlabel('f(X)','FontName','Times','FontSize',20,'FontAngle','italic');
title('X-Y Plane View','FontName','Times','FontSize',24,'FontWeight','bold');

figure(3)
mesh(x1,x2,f_tot);view(90,0);colorbar;set(gca,'FontSize',12);
xlabel('x_2','FontName','Times','FontSize',20,'FontAngle','italic');
ylabel('x_1','FontName','Times','FontSize',20,'FontAngle','italic');
zlabel('f(X)','FontName','Times','FontSize',20,'FontAngle','italic');
title('X-Z Plane View','FontName','Times','FontSize',24,'FontWeight','bold');

figure(4)
mesh(x1,x2,f_tot);view(0,0);colorbar;set(gca,'FontSize',12);
xlabel('x_2','FontName','Times','FontSize',20,'FontAngle','italic');
ylabel('x_1','FontName','Times','FontSize',20,'FontAngle','italic');
zlabel('f(X)','FontName','Times','FontSize',20,'FontAngle','italic');
title('Y-Z Plane View','FontName','Times','FontSize',24,'FontWeight','bold');

Click here to download m-file

 

VI. References:

[1] M. Vrahatis, D. Sotiropoulos, and E. Triantafyllou, "Global Optimization for Imprecise Problems," in Developments in Global Optimization, ser. Nonconvex Optimization and Its Applications, I. Bomze, T. Csendes, R. Horst, and P. Pardalos, Eds. Springer US, 1997, vol. 18, pp. 37-54. [Online]. Available: http://dx.doi.org/10.1007/978-1-4757-2600-8_3
[2] B. Kearfott, "An Efficient Degree-Computation Method for a Generalized Method of Bisection," Numerische Mathematik, vol. 32, no. 2, pp. 109-127, 1979.
[3] E. Onbaşoğlu and L. Özdamar, "Parallel Simulated Annealing Algorithms in Global Optimization," Journal of Global Optimization, vol. 19, no. 1, pp. 27-50, Jan. 2001.
[4] Ali R. Alroomi, "The Farm of Unconstrained Benchmark Functions," University of Bahrain, Electrical and Electronics Department, Bahrain, Oct. 2013. [Online]. Available: http://www.al-roomi.org/cv/publications