format long %Scaled fixed point format, with 15 digits for double; 8 digits for single.
x=[0,0];
x=input('請輸入初始值[x0,x1]=');
s=input('請輸入初始精度s＝');
g=D_F(x);
g=g.';%轉(zhuǎn)置為列向量；
while(norm(g)>s) 
    s_k=-g,   r=min_F(x,s_k),   x=x+r.*s_k.',
    g=D_F(x);
    g=g.';
    fprintf('The result is %8.5f\n', x); 
    fprintf('The daosu is %8.5f\n', g);   
end
%axis normal;
%hold on;
%view([1,1,1]);
%view(30,45);
[x,y]=meshgrid(-50:1:100);
z=peaks(x,y);
for i=-50:100
    for j=-50:100
        z=[i,j];  z=F(z);
        plot3(i,j,z);
    end
end
grid on;
%hold off;
%x=meshgrid(-50,1,100);