带原点位移的qr方法的MATLAB程序function QR = qr_shiftA QR factorization with shift A input matrix Q orthogonal matrix R upper triangular matrix Author Lisha Chen Date Jan 25th 2021mn = sizeA;Q进行QR分解的过程直到矩阵A变成上三角矩

while m > n % Choose shift s = A(n,n);

% QR factorization with shift
[Q,R] = qr(A - s*eye(m));

% Update A
A = R*Q + s*eye(m);

% Update m and n
m = m - 1;
n = n - 1;

end

% Final QR factorization without shift [Q,R] = qr(A);

% Check if A is close to upper triangular if norm(triu(A,1)) > 1e-10 warning('A is not upper triangular'); end

end