zungrq(3P) Sun Performance Library zungrq(3P)NAMEzungrq - generate an M-by-N complex matrix Q with orthonormal rows,
SYNOPSIS
SUBROUTINE ZUNGRQ(M, N, K, A, LDA, TAU, WORK, LWORK, INFO)
DOUBLE COMPLEX A(LDA,*), TAU(*), WORK(*)
INTEGER M, N, K, LDA, LWORK, INFO
SUBROUTINE ZUNGRQ_64(M, N, K, A, LDA, TAU, WORK, LWORK, INFO)
DOUBLE 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(8), DIMENSION(:) :: TAU, WORK
COMPLEX(8), DIMENSION(:,:) :: A
INTEGER :: M, N, K, LDA, LWORK, INFO
SUBROUTINE UNGRQ_64(M, [N], [K], A, [LDA], TAU, [WORK], [LWORK],
[INFO])
COMPLEX(8), DIMENSION(:) :: TAU, WORK
COMPLEX(8), DIMENSION(:,:) :: A
INTEGER(8) :: M, N, K, LDA, LWORK, INFO
C INTERFACE
#include <sunperf.h>
void zungrq(int m, int n, int k, doublecomplex *a, int lda, doublecom‐
plex *tau, int *info);
void zungrq_64(long m, long n, long k, doublecomplex *a, long lda, dou‐
blecomplex *tau, long *info);
PURPOSEzungrq 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 ZGERQF.
ARGUMENTS
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 vector which
defines the elementary reflector H(i), for i = 1,2,...,k, as
returned by ZGERQF 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 elementary
reflector H(i), as returned by ZGERQF.
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 illegal value
6 Mar 2009 zungrq(3P)