Contents
cungrq - generate an M-by-N complex matrix Q with orthonor-
mal rows,
SUBROUTINE CUNGRQ(M, N, K, A, LDA, TAU, WORK, LWORK, INFO)
COMPLEX A(LDA,*), TAU(*), WORK(*)
INTEGER M, N, K, LDA, LWORK, INFO
SUBROUTINE CUNGRQ_64(M, N, K, A, LDA, TAU, WORK, LWORK, INFO)
COMPLEX A(LDA,*), TAU(*), WORK(*)
INTEGER*8 M, N, K, LDA, LWORK, INFO
F95 INTERFACE
SUBROUTINE UNGRQ(M, [N], [K], A, [LDA], TAU, [WORK], [LWORK], [INFO])
COMPLEX, DIMENSION(:) :: TAU, WORK
COMPLEX, DIMENSION(:,:) :: A
INTEGER :: M, N, K, LDA, LWORK, INFO
SUBROUTINE UNGRQ_64(M, [N], [K], A, [LDA], TAU, [WORK], [LWORK],
[INFO])
COMPLEX, DIMENSION(:) :: TAU, WORK
COMPLEX, DIMENSION(:,:) :: A
INTEGER(8) :: M, N, K, LDA, LWORK, INFO
C INTERFACE
#include <sunperf.h>
void cungrq(int m, int n, int k, complex *a, int lda, com-
plex *tau, int *info);
void cungrq_64(long m, long n, long k, complex *a, long lda,
complex *tau, long *info);
cungrq generates an M-by-N complex 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 CGERQF.
M (input) The number of rows of the matrix Q. M >= 0.
N (input) The number of columns of the matrix Q. N >= M.
K (input) The number of elementary reflectors whose product
defines the matrix Q. M >= K >= 0.
A (input/output)
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 CGERQF in the
last k rows of its array argument A. On exit, the
M-by-N matrix Q.
LDA (input)
The first dimension of the array A. LDA >=
max(1,M).
TAU (input)
TAU(i) must contain the scalar factor of the ele-
mentary reflector H(i), as returned by CGERQF.
WORK (workspace)
On exit, if INFO = 0, WORK(1) returns the optimal
LWORK.
LWORK (input)
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.
INFO (output)
= 0: successful exit
< 0: if INFO = -i, the i-th argument has an ille-
gal value