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/home/abuild/rpmbuild/BUILD/lapack-3.12.0/TESTING/LIN/dqrt02.f(3) Library Functions Manual /home/abuild/rpmbuild/BUILD/lapack-3.12.0/TESTING/LIN/dqrt02.f(3)

NAME

/home/abuild/rpmbuild/BUILD/lapack-3.12.0/TESTING/LIN/dqrt02.f

SYNOPSIS

Functions/Subroutines


subroutine DQRT02 (m, n, k, a, af, q, r, lda, tau, work, lwork, rwork, result)
DQRT02

Function/Subroutine Documentation

subroutine DQRT02 (integer m, integer n, integer k, 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)

DQRT02

Purpose:

!>
!> DQRT02 tests DORGQR, which generates an m-by-n matrix Q with
!> orthonormal columns that is defined as the product of k elementary
!> reflectors.
!>
!> Given the QR factorization of an m-by-n matrix A, DQRT02 generates
!> the orthogonal matrix Q defined by the factorization of the first k
!> columns of A; it compares R(1:n,1:k) with Q(1:m,1:n)'*A(1:m,1:k),
!> and checks that the columns of Q are orthonormal.
!>

Parameters

M 

!>          M is INTEGER
!>          The number of rows of the matrix Q to be generated.  M >= 0.
!>

N

!>          N is INTEGER
!>          The number of columns of the matrix Q to be generated.
!>          M >= N >= 0.
!>

K

!>          K is INTEGER
!>          The number of elementary reflectors whose product defines the
!>          matrix Q. N >= K >= 0.
!>

A

!>          A is DOUBLE PRECISION array, dimension (LDA,N)
!>          The m-by-n matrix A which was factorized by DQRT01.
!>

AF

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

Q

!>          Q is DOUBLE PRECISION array, dimension (LDA,N)
!>

R

!>          R is DOUBLE PRECISION array, dimension (LDA,N)
!>

LDA

!>          LDA is INTEGER
!>          The leading dimension of the arrays A, AF, Q and R. LDA >= M.
!>

TAU

!>          TAU is DOUBLE PRECISION array, dimension (N)
!>          The scalar factors of the elementary reflectors corresponding
!>          to the QR factorization in AF.
!>

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

Univ. of Colorado Denver

NAG Ltd.

Definition at line 133 of file dqrt02.f.

Author

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Version 3.12.0 LAPACK