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/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/dorg2r.f(3) Library Functions Manual /home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/dorg2r.f(3)

NAME

/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/dorg2r.f

SYNOPSIS

Functions/Subroutines


subroutine DORG2R (m, n, k, a, lda, tau, work, info)
DORG2R generates all or part of the orthogonal matrix Q from a QR factorization determined by sgeqrf (unblocked algorithm).

Function/Subroutine Documentation

subroutine DORG2R (integer m, integer n, integer k, double precision, dimension( lda, * ) a, integer lda, double precision, dimension( * ) tau, double precision, dimension( * ) work, integer info)

DORG2R generates all or part of the orthogonal matrix Q from a QR factorization determined by sgeqrf (unblocked algorithm).

Purpose:

!>
!> DORG2R generates an m by n real matrix Q with orthonormal columns,
!> which is defined as the first n columns of a product of k elementary
!> reflectors of order m
!>
!>       Q  =  H(1) H(2) . . . H(k)
!>
!> as returned by DGEQRF.
!>

Parameters

M 

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

N

!>          N is INTEGER
!>          The number of columns of the matrix Q. 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)
!>          On entry, the i-th column must contain the vector which
!>          defines the elementary reflector H(i), for i = 1,2,...,k, as
!>          returned by DGEQRF in the first k columns of its array
!>          argument A.
!>          On exit, the m-by-n matrix Q.
!>

LDA

!>          LDA is INTEGER
!>          The first dimension of the array A. LDA >= max(1,M).
!>

TAU

!>          TAU is DOUBLE PRECISION array, dimension (K)
!>          TAU(i) must contain the scalar factor of the elementary
!>          reflector H(i), as returned by DGEQRF.
!>

WORK

!>          WORK is DOUBLE PRECISION array, dimension (N)
!>

INFO

!>          INFO is INTEGER
!>          = 0: successful exit
!>          < 0: if INFO = -i, the i-th argument has an illegal value
!>

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 113 of file dorg2r.f.

Author

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Version 3.12.0 LAPACK