.TH DORGLQ 1 "November 2006" " LAPACK routine (version 3.1) " " LAPACK routine (version 3.1) "
.SH NAME
DORGLQ - an M-by-N real matrix Q with orthonormal rows,
.SH SYNOPSIS
.TP 19
SUBROUTINE DORGLQ(
M, N, K, A, LDA, TAU, WORK, LWORK, INFO )
.TP 19
.ti +4
INTEGER
INFO, K, LDA, LWORK, M, N
.TP 19
.ti +4
DOUBLE
PRECISION A( LDA, * ), TAU( * ), WORK( * )
.SH PURPOSE
DORGLQ generates an M-by-N real matrix Q with orthonormal rows,
which is defined as the first M rows of a product of K elementary
reflectors of order N
.br
Q = H(k) . . . H(2) H(1)
.br
as returned by DGELQF.
.br
.SH ARGUMENTS
.TP 8
M (input) INTEGER
The number of rows of the matrix Q. M >= 0.
.TP 8
N (input) INTEGER
The number of columns of the matrix Q. N >= M.
.TP 8
K (input) INTEGER
The number of elementary reflectors whose product defines the
matrix Q. M >= K >= 0.
.TP 8
A (input/output) DOUBLE PRECISION array, dimension (LDA,N)
On entry, the i-th row must contain the vector which defines
the elementary reflector H(i), for i = 1,2,...,k, as returned
by DGELQF in the first k rows of its array argument A.
On exit, the M-by-N matrix Q.
.TP 8
LDA (input) INTEGER
The first dimension of the array A. LDA >= max(1,M).
.TP 8
TAU (input) DOUBLE PRECISION array, dimension (K)
TAU(i) must contain the scalar factor of the elementary
reflector H(i), as returned by DGELQF.
.TP 8
WORK (workspace/output) DOUBLE PRECISION array, dimension (MAX(1,LWORK))
On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
.TP 8
LWORK (input) INTEGER
The dimension of the array WORK. LWORK >= max(1,M).
For optimum performance LWORK >= M*NB, where NB is
the optimal blocksize.
If LWORK = -1, then a workspace query is assumed; the routine
only calculates the optimal size of the WORK array, returns
this value as the first entry of the WORK array, and no error
message related to LWORK is issued by XERBLA.
.TP 8
INFO (output) INTEGER
= 0: successful exit
.br
< 0: if INFO = -i, the i-th argument has an illegal value