SLAPLL
November 2006
Purpose
Given two column vectors X and Y, let
A = ( X Y ).
The subroutine first computes the QR factorization of A = Q*R,
and then computes the SVD of the 2-by-2 upper triangular matrix R.
The smaller singular value of R is returned in SSMIN, which is used
as the measurement of the linear dependency of the vectors X and Y.
A = ( X Y ).
The subroutine first computes the QR factorization of A = Q*R,
and then computes the SVD of the 2-by-2 upper triangular matrix R.
The smaller singular value of R is returned in SSMIN, which is used
as the measurement of the linear dependency of the vectors X and Y.
Arguments
| N |
(input) INTEGER
The length of the vectors X and Y.
|
| X |
(input/output) REAL array,
dimension (1+(N-1)*INCX)
On entry, X contains the N-vector X. On exit, X is overwritten. |
| INCX |
(input) INTEGER
The increment between successive elements of X. INCX > 0.
|
| Y |
(input/output) REAL array,
dimension (1+(N-1)*INCY)
On entry, Y contains the N-vector Y. On exit, Y is overwritten. |
| INCY |
(input) INTEGER
The increment between successive elements of Y. INCY > 0.
|
| SSMIN |
(output) REAL
The smallest singular value of the N-by-2 matrix A = ( X Y ).
|