梯度法.m

罚函数法matlab程序.希望对大家有用.

%主函数main.m
clc
clear
a=input('请输入根的下限：');
b=input('请输入根的上限：');
e=input('请输入允许误差：');
dx=input('请输入检测步长：');


x1=a;
x2=b;
d1=-[4*x1;2*x2];
d=sqrt((4*x1)^2+(2*x2)^2);
cout=0;
if d>e
    x3=x1-dx*x1;   
    x4=x2-dx*x2;
    cout=1;
    d=sqrt((4*x3)^2+(2*x2)^2);
    while d>e
        x1=x3;
        x2=x4;
        x3=x1-dx*x1;   
        x4=x2-dx*x2;
        cout=cout+1;
        d=sqrt((4*x3)^2+(2*x2)^2);
    end
else
    x3=x1;
    x4=x1;
end

fprintf('近似解是：\n');
[x3;x4]
fprintf('迭代次数cout是：\n');
cout