lis_array_qr.3f - Man Page
calculate the eigenvalues with the QR algorithm
Synopsis
subroutine lis_array_cgs(LIS_INTEGER n, LIS_SCALAR a(), LIS_SCALAR q(), LIS_SCALAR r(), LIS_INTEGER qriter, LIS_SCALAR qrerr, LIS_INTEGER ierr);
Description
Calculate the eigenvalues of matrix A with the QR algorithm.
Input
- n
The size of the matrices
- a
The array that stores matrix A of size n * n
- q
The work array Q of size n * n
- r
The work array R of size n * n
Output
- a
The array that stores the block upper-triangular matrix with eigenvalues in the block diagonal elements after similarity transformation
- qriter
The number of iterations of the QR algorithm
- qrerr
The 2-norm of the first subdiagonal element A(2,1) after similarity transformation
See Also
Info
1 Nov 2014 Man Page Lis Library Functions