qrtrannnn

代码说明：

  功能：对矩阵A的左上角的m阶对角块作QR变换：先用Givens变换作QR分解A=QR， 再作相似变换A:=Q AQ=RQ. 输入: n阶HessenbergA，其中A(m+1,m)=0,m>2. 输出: 变换后的Hessenberg形矩阵A. 2 用基本QR算法求实方阵的全部特征值.(Function: the upper left corner of the matrix A, diagonal blocks of order m to QR transformation: first, to make QR decomposition using Givens transformations A = QR, re-similarity transformation A: = Q' AQ = RQ. Input: n-order HessenbergA, where A (m+1, m) = 0, m> 2. Output: transformed Hessenberg form matrix A. 2 matrix with the basic QR algorithm for all the characteristics of the value of truth-seeking.)