# dlapll.f - Man Page

## Synopsis

### Functions/Subroutines

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

## Function/Subroutine Documentation

### subroutine dlapll (integer N, double precision, dimension( * ) X, integer INCX, double precision, dimension( * ) Y, integer INCY, double precision SSMIN)

**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:**December 2016

Definition at line 104 of file dlapll.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

The man page dlapll(3) is an alias of dlapll.f(3).

Tue Nov 14 2017 Version 3.8.0 LAPACK