QR_eigenvalue.m

function [lamta]=QR_eigenvalue(A)
% QR方法计算矩阵特征值
[m,n]=size(A);i=1;

while n>=1
    delts=1;
    while abs(delts)>1e-6
    s=A(n,n);
    A=A-s*eye(n);
    [Q,R]=H_QR(A);
    A=R*Q+s*eye(n);
    s2=A(n,n);
    delts=(s2-s)/s;
    end
    lamta(i)=s;
    i=i+1;
    n=n-1;
    A=A(1:n,1:n);
end