DLAPLL(3)
two column vectors X and Y, let A = ( X Y )
SYNOPSIS
 SUBROUTINE DLAPLL(

N, X, INCX, Y, INCY, SSMIN )

INTEGER
INCX, INCY, N

DOUBLE
PRECISION SSMIN

DOUBLE
PRECISION 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 2by2 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) DOUBLE PRECISION array,

dimension (1+(N1)*INCX)
On entry, X contains the Nvector X.
On exit, X is overwritten.
 INCX (input) INTEGER

The increment between successive elements of X. INCX > 0.
 Y (input/output) DOUBLE PRECISION array,

dimension (1+(N1)*INCY)
On entry, Y contains the Nvector Y.
On exit, Y is overwritten.
 INCY (input) INTEGER

The increment between successive elements of Y. INCY > 0.
 SSMIN (output) DOUBLE PRECISION

The smallest singular value of the Nby2 matrix A = ( X Y ).