SORGR2 - generate an m by n real matrix Q with orthonormal
rows,
SYNOPSIS
SUBROUTINE SORGR2( M, N, K, A, LDA, TAU, WORK, INFO )
INTEGER INFO, K, LDA, M, N
REAL A( LDA, * ), TAU( * ), WORK( * )
PURPOSE
SORGR2 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 SGERQF.
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) REAL 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 SGERQF 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) REAL array, dimension (K)
TAU(i) must contain the scalar factor of the ele
mentary reflector H(i), as returned by SGERQF.
WORK (workspace) REAL array, dimension (M)
INFO (output) INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument has an ille
gal value
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