fig4_5.m

good code for matlab by mili , i than you

% Unconstrained Optimization%  
%	Dr. P.Venkataraman
%
%	section 4.3.1, Figure 4.6
% additional graphics through plotedit
%

x1=0:.05:4;	
x2=0:0.05:4;
[X1 X2]=meshgrid(x1,x2); % X,Y are matrices

fval=(X1-1).^2 +(X2-1).^2 -X1.*X2;	% could have used an m-file

[c1,h1]= contour(x1,x2,fval,[-1.99 -1.5 -1 0 1],'k');
% draws the specified contours
% and establishes handles to set properties of plot               
set(h1,'LineWidth',1);
axis([0 4 0 4]);
clabel(c1);	% labels contours
xlabel('x_1');
ylabel('x_2');

% draw the design space
line([0 3],[0 0],'Color','b', ...
      'LineWidth',1);
line([3 3],[0 3],'Color','b', ...
      'LineWidth',1);
line([3 0],[3 3],'Color','b', ...
      'LineWidth',1);
line([0 0],[3 0],'Color','b', ...
      'LineWidth',1);
grid
hold on 
plot(2,2,'mo')
text(2.05,2.05,'(x_1^*,x_2^*)')
hold off