CLAPLL(1) LAPACK auxiliary routine (version 3.2) CLAPLL(1)NAME
CLAPLL - two column vectors X and Y, let A = ( X Y )
SYNOPSIS
SUBROUTINE CLAPLL( N, X, INCX, Y, INCY, SSMIN )
INTEGER INCX, INCY, N
REAL SSMIN
COMPLEX X( * ), Y( * )
PURPOSE
Given two column vectors X and Y, let 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) COMPLEX array, dimension (1+(N-1)*INCX)
On entry, X contains the N-vector X. On exit, X is overwrit‐
ten.
INCX (input) INTEGER
The increment between successive elements of X. INCX > 0.
Y (input/output) COMPLEX array, dimension (1+(N-1)*INCY)
On entry, Y contains the N-vector Y. On exit, Y is overwrit‐
ten.
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 ).
LAPACK auxiliary routine (versioNovember 2008 CLAPLL(1)
