cungqr(3P) Sun Performance Library cungqr(3P)NAMEcungqr - generate an M-by-N complex matrix Q with orthonormal columns,
SYNOPSIS
SUBROUTINE CUNGQR(M, N, K, A, LDA, TAU, WORKIN, LWORKIN, INFO)
COMPLEX A(LDA,*), TAU(*), WORKIN(*)
INTEGER M, N, K, LDA, LWORKIN, INFO
SUBROUTINE CUNGQR_64(M, N, K, A, LDA, TAU, WORKIN, LWORKIN, INFO)
COMPLEX A(LDA,*), TAU(*), WORKIN(*)
INTEGER*8 M, N, K, LDA, LWORKIN, INFO
F95 INTERFACE
SUBROUTINE UNGQR(M, [N], [K], A, [LDA], TAU, [WORKIN], [LWORKIN],
[INFO])
COMPLEX, DIMENSION(:) :: TAU, WORKIN
COMPLEX, DIMENSION(:,:) :: A
INTEGER :: M, N, K, LDA, LWORKIN, INFO
SUBROUTINE UNGQR_64(M, [N], [K], A, [LDA], TAU, [WORKIN], [LWORKIN],
[INFO])
COMPLEX, DIMENSION(:) :: TAU, WORKIN
COMPLEX, DIMENSION(:,:) :: A
INTEGER(8) :: M, N, K, LDA, LWORKIN, INFO
C INTERFACE
#include <sunperf.h>
void cungqr(int m, int n, int k, complex *a, int lda, complex *tau, int
*info);
void cungqr_64(long m, long n, long k, complex *a, long lda, complex
*tau, long *info);
PURPOSEcungqr generates an M-by-N complex matrix Q with orthonormal columns,
which is defined as the first N columns of a product of K elementary
reflectors of order M
Q = H(1)H(2) . . . H(k)
as returned by CGEQRF.
ARGUMENTS
M (input) The number of rows of the matrix Q. M >= 0.
N (input) The number of columns of the matrix Q. M >= N >= 0.
K (input) The number of elementary reflectors whose product defines the
matrix Q. N >= K >= 0.
A (input/output)
On entry, the i-th column must contain the vector which
defines the elementary reflector H(i), for i = 1,2,...,k, as
returned by CGEQRF in the first k columns of its array argu‐
ment 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 CGEQRF.
WORKIN (workspace)
On exit, if INFO = 0, WORKIN(1) returns the optimal LWORKIN.
LWORKIN (input)
The dimension of the array WORKIN. LWORKIN >= max(1,N). For
optimum performance LWORKIN >= N*NB, where NB is the optimal
blocksize.
If LWORKIN = -1, then a workspace query is assumed; the rou‐
tine only calculates the optimal size of the WORKIN array,
returns this value as the first entry of the WORKIN array,
and no error message related to LWORKIN is issued by XERBLA.
INFO (output)
= 0: successful exit
< 0: if INFO = -i, the i-th argument has an illegal value
6 Mar 2009 cungqr(3P)
