untitledtezhengzhi.m

数值计算实践是我们必备的一门学科！这是我在学习之余利用MATLAB编写的程序

A=[2,-1,0;-1,2,-1;0,-1,2];
u0=[1;1;1];
u0max=max(u0);
u0min=min(u0);
if abs(u0max)>=abs(u0min)
    a=u0max;
else
    a=u0min;
end
y0=sign(a)*u0/abs(a);
u1=A*y0;
for i=1:3
    if (a==u0(i))
        r=i;
    end
end
k=0;
t1=sign(a)*u1(r);
lmda=t1;
fprintf(' k    u(k)_1    u(k)_2    u(k)_3    lamda\n')
fprintf('%2d     %12.9f     %12.9f      %12.9f    %12.9f\n',k,y0,lmda)
for k=1:10
    u0=u1;
    u0max=max(u0);
    u0min=min(u0);
    if abs(u0max)>=abs(u0min)
        a=u0max;
    else
        a=u0min;
    end
    y0=sign(a)*u0/abs(a);
    for i=1:3
        if (a==u0(i))
            r=i;
        end
    end
    u1=A*y0;
    t1=sign(a)*u0(r);
    lmda=t1;
    x=y0;
    fprintf('%2d %12.9f %12.9f %12.9f %12.9f\n',k,y0,lmda)
end