syms x1 y1

% hold off
step = 0.1;
[x,y] = meshgrid(-5:step:5, -5:step:5);

% func =  sym('A^2 + B^2')
func = sym('(1-x1)^2 + 100*(y1-x1^2)^2');
% func = sym('2*x1^2 + y1^2 + x1*y1')
% func = sym('-2*x1^2 - y1^2 + x1*y1')
func_hl = matlabFunction(func);

z = func_hl(x,y);

stX = -3;
stY = -3.5;

H = 0.00005;

hold on;
contour(x,y,z, 128);
% clabel(C, h);    % Отображение меток на линиях уровня
% quiver(x,y,gx,gy);


X = stX, Y=stY
plot(X,Y,'+');
% break

for i=1:200
    derivateX = diff(func, x1);
    derivateX = matlabFunction(derivateX);

    derX = derivateX(X, Y);

    derivateY = diff(func, y1);
    derivateY = matlabFunction(derivateY);

    derY = derivateY(X, Y)

    derX = derX * H;
    derY = derY * H;


     X = X - derX
     Y = Y - derY

     plot(X,Y,'x');

 end


% hold on
hold off;