CUNGLQ(l) LAPACK routine (version 1.1) CUNGLQ(l)
NAME
CUNGLQ - generate an M-by-N complex matrix Q with orthonormal rows,
SYNOPSIS
SUBROUTINE CUNGLQ( M, N, K, A, LDA, TAU, WORK, LWORK, INFO )
INTEGER INFO, K, LDA, LWORK, M, N
COMPLEX A( LDA, * ), TAU( * ), WORK( LWORK )
PURPOSE
CUNGLQ generates an M-by-N complex matrix Q with orthonormal rows, which is
defined as the first M rows of a product of K elementary reflectors of
order N
Q = H(k)' . . . H(2)' H(1)'
as returned by CGELQF.
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) COMPLEX 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 CGELQF
in the first 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) COMPLEX array, dimension (K)
TAU(i) must contain the scalar factor of the elementary reflector
H(i), as returned by CGELQF.
WORK (workspace) COMPLEX array, dimension (LWORK)
On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
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.
INFO (output) INTEGER
= 0: successful exit;
< 0: if INFO = -i, the i-th argument has an illegal value
Back to the listing of computational routines for orthogonal factorization and singular
value decomposition