dlapll.f man page

dlapll.f —

Synopsis

Functions/Subroutines

subroutine dlapll (N, X, INCX, Y, INCY, SSMIN)
DLAPLL measures the linear dependence of two vectors.

Function/Subroutine Documentation

subroutine dlapll (integerN, double precision, dimension( * )X, integerINCX, double precision, dimension( * )Y, integerINCY, double precisionSSMIN)

DLAPLL measures the linear dependence of two vectors.

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.

Parameters:

N

N is INTEGER
The length of the vectors X and Y.

X

X is DOUBLE PRECISION array,
               dimension (1+(N-1)*INCX)
On entry, X contains the N-vector X.
On exit, X is overwritten.

INCX

INCX is INTEGER
The increment between successive elements of X. INCX > 0.

Y

Y is DOUBLE PRECISION array,
               dimension (1+(N-1)*INCY)
On entry, Y contains the N-vector Y.
On exit, Y is overwritten.

INCY

INCY is INTEGER
The increment between successive elements of Y. INCY > 0.

SSMIN

SSMIN is DOUBLE PRECISION
The smallest singular value of the N-by-2 matrix A = ( X Y ).

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

September 2012

Definition at line 103 of file dlapll.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

dlapll(3) is an alias of dlapll.f(3).

Sat Nov 16 2013 Version 3.4.2 LAPACK