clear all
close all
[X,Y] = meshgrid(-5:0.1:5);
F = (X + 2).^2 + (Y + 2).^2;
figure(1)
contour(X,Y,F,100,'k')
axis equal
Z = zeros(size(F));
G = (Y - X);
P = max(G,Z).^2;
miu = 10;
T = F + miu*P;
figure(2)
contour(X,Y, F, 50, 'k')
hold on
x = -5:0.01:5;
y = x+2;
plot(x,y,'r')
axis([-5 5 -5 5])
axis equal
zlim([-10 10])
R = 0.25;
epsilon = 0.001;
x0=[1 4];
xs=x0;
itsk = 200;
step=0.1;
for i=1:itsk
x0 = xs - step * gradient1(xs,R);
plot([xs(1),x0(1)],[xs(2),x0(2)],'r',[xs(1),x0(1)],[xs(2),x0(2)],'ro')
d = abs(xs - x0);
xs=x0;
%R = R/5;
if(d < epsilon)
break;
end
end
function gr = gradient1(x,R)
gr(1) = (2*(R*(x(1) + 2) + x(1) - x(2)))/R;
gr(2) = (2*(R*(x(2) + 2) - x(1) + x(2)))/R;
end