function y = min_F(x,s_k)
%MIN_F Summary of this function goes here
%  Detailed explanation goes here
% 一維搜索,黃金分割法
a=0;
b=50;
l=0.000001;%終止精度
s_temp=s_k.';
x1=a+0.382*(b-a);
x2=a+b-x1;
while(abs(b-a)>l)
    x_temp1=x+x1.*s_temp;%R
    x_temp2=x+x2.*s_temp;%G
    if(F(x_temp1)>F(x_temp2))
        a=x1;
        if (abs(b-a)>l)  
            x1=x2;  x2=a+0.618*(b-a);  
        end    
    else
        b=x2;
        if (abs(b-a)>l) 
            x2=x1;  x1=a+0.382*(b-a);  
        end 
    end
end
y=(a+b)/2;