slapll(3)

NAME

SLAPLL - two column vectors X and Y, let A = ( X Y )

SYNOPSIS

SUBROUTINE SLAPLL( N, X, INCX, Y, INCY, SSMIN )
    INTEGER        INCX, INCY, N
    REAL           SSMIN
    REAL           X( * ), Y( * )

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.

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 ).

LAPACK version 3.0 15 June 2000

SLAPLL(3)