# dqrt01p.f - Man Page

TESTING/LIN/dqrt01p.f

## Synopsis

### Functions/Subroutines

subroutine dqrt01p (m, n, a, af, q, r, lda, tau, work, lwork, rwork, result)
DQRT01P

## Function/Subroutine Documentation

### subroutine dqrt01p (integer m, integer n, double precision, dimension( lda, * ) a, double precision, dimension( lda, * ) af, double precision, dimension( lda, * ) q, double precision, dimension( lda, * ) r, integer lda, double precision, dimension( * ) tau, double precision, dimension( lwork ) work, integer lwork, double precision, dimension( * ) rwork, double precision, dimension( * ) result)

DQRT01P

Purpose:

DQRT01P tests DGEQRFP, which computes the QR factorization of an m-by-n
matrix A, and partially tests DORGQR which forms the m-by-m
orthogonal matrix Q.

DQRT01P compares R with Q'*A, and checks that Q is orthogonal.
Parameters

M

M is INTEGER
The number of rows of the matrix A.  M >= 0.

N

N is INTEGER
The number of columns of the matrix A.  N >= 0.

A

A is DOUBLE PRECISION array, dimension (LDA,N)
The m-by-n matrix A.

AF

AF is DOUBLE PRECISION array, dimension (LDA,N)
Details of the QR factorization of A, as returned by DGEQRFP.
See DGEQRFP for further details.

Q

Q is DOUBLE PRECISION array, dimension (LDA,M)
The m-by-m orthogonal matrix Q.

R

R is DOUBLE PRECISION array, dimension (LDA,max(M,N))

LDA

LDA is INTEGER
The leading dimension of the arrays A, AF, Q and R.
LDA >= max(M,N).

TAU

TAU is DOUBLE PRECISION array, dimension (min(M,N))
The scalar factors of the elementary reflectors, as returned
by DGEQRFP.

WORK

WORK is DOUBLE PRECISION array, dimension (LWORK)

LWORK

LWORK is INTEGER
The dimension of the array WORK.

RWORK

RWORK is DOUBLE PRECISION array, dimension (M)

RESULT

RESULT is DOUBLE PRECISION array, dimension (2)
The test ratios:
RESULT(1) = norm( R - Q'*A ) / ( M * norm(A) * EPS )
RESULT(2) = norm( I - Q'*Q ) / ( M * EPS )
Author

Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Definition at line 124 of file dqrt01p.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

The man page dqrt01p(3) is an alias of dqrt01p.f(3).

Tue Nov 28 2023 12:08:43 Version 3.12.0 LAPACK