DORGR2(1) LAPACK routine (version 3.2) DORGR2(1)NAME
DORGR2 - generates an m by n real matrix Q with orthonormal rows,
SYNOPSIS
SUBROUTINE DORGR2( M, N, K, A, LDA, TAU, WORK, INFO )
INTEGER INFO, K, LDA, M, N
DOUBLE PRECISION A( LDA, * ), TAU( * ), WORK( * )
PURPOSE
DORGR2 generates an m by n real matrix Q with orthonormal rows, which
is defined as the last m rows of a product of k elementary reflectors
of order n
Q = H(1)H(2) . . . H(k)
as returned by DGERQF.
ARGUMENTS
M (input) INTEGER
The number of rows of the matrix Q. M >= 0.
N (input) INTEGER
The number of columns of the matrix Q. N >= M.
K (input) INTEGER
The number of elementary reflectors whose product defines the
matrix Q. M >= K >= 0.
A (input/output) DOUBLE PRECISION array, dimension (LDA,N)
On entry, the (m-k+i)-th row must contain the vector which
defines the elementary reflector H(i), for i = 1,2,...,k, as
returned by DGERQF in the last k rows of its array argument A.
On exit, the m by n matrix Q.
LDA (input) INTEGER
The first dimension of the array A. LDA >= max(1,M).
TAU (input) DOUBLE PRECISION array, dimension (K)
TAU(i) must contain the scalar factor of the elementary reflec‐
tor H(i), as returned by DGERQF.
WORK (workspace) DOUBLE PRECISION array, dimension (M)
INFO (output) INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument has an illegal value
LAPACK routine (version 3.2) November 2008 DORGR2(1)
