DORGR2 - generate 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 vec
tor 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 ele
mentary reflector 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
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