function [ output_args ] = Gong_E( input_args )
%GONG_E Summary of this function goes here
%  Detailed explanation goes here
times=1,  circles=1;
x1=input('請輸入初始點[x1,x2]=');
s=input('請輸入精度s=');
xk=x1;
xk_1=x1;
d_x1=D_F(x1);%求出初始點導數
d_xk=d_x1;
d_xk_1=d_x1;
if(norm(d_x1,2)<s)%求出向量d_x1的范數
  fprintf('最小值為\n:') ;
  disp(x1);
  fprintf('迭代步數：\n');
  disp(circles);
  return;
else
  while(norm(d_xk_1)>s)
       z_k=-D_F(x1);
       while(times<2)
           circles=circles+1;
           p=min_F1(xk,z_k);
           xk_1=xk+p.*z_k;
           d_xk_1=D_F(xk_1);%k+1 gradient
           if(norm(d_xk_1)<s)
              fprintf('最小值為\n:') ;
              disp(xk_1);
              fprintf('迭代步數：\n');
              disp(circles);
              return;       
           else
              times=times+1;
              ak=(norm(d_xk_1))^2/(norm(d_xk))^2;
              z_k_1=-d_xk_1+ak.*z_k;
              z_k=z_k_1;
              xk=xk_1;
              d_xk=d_xk_1;
           end
       end
       times=1;
       x1=xk_1;      
  end
end