sorgqr(3P) Sun Performance Library sorgqr(3P)NAMEsorgqr - generate an M-by-N real matrix Q with orthonormal columns,
SYNOPSIS
SUBROUTINE SORGQR(M, N, K, A, LDA, TAU, WORK, LDWORK, INFO)
INTEGER M, N, K, LDA, LDWORK, INFO
REAL A(LDA,*), TAU(*), WORK(*)
SUBROUTINE SORGQR_64(M, N, K, A, LDA, TAU, WORK, LDWORK, INFO)
INTEGER*8 M, N, K, LDA, LDWORK, INFO
REAL A(LDA,*), TAU(*), WORK(*)
F95 INTERFACE
SUBROUTINE ORGQR(M, [N], [K], A, [LDA], TAU, [WORK], [LDWORK], [INFO])
INTEGER :: M, N, K, LDA, LDWORK, INFO
REAL, DIMENSION(:) :: TAU, WORK
REAL, DIMENSION(:,:) :: A
SUBROUTINE ORGQR_64(M, [N], [K], A, [LDA], TAU, [WORK], [LDWORK],
[INFO])
INTEGER(8) :: M, N, K, LDA, LDWORK, INFO
REAL, DIMENSION(:) :: TAU, WORK
REAL, DIMENSION(:,:) :: A
C INTERFACE
#include <sunperf.h>
void sorgqr(int m, int n, int k, float *a, int lda, float *tau, int
*info);
void sorgqr_64(long m, long n, long k, float *a, long lda, float *tau,
long *info);
PURPOSEsorgqr generates an M-by-N real 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 SGEQRF.
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 SGEQRF 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 SGEQRF.
WORK (workspace)
On exit, if INFO = 0, WORK(1) returns the optimal LDWORK.
LDWORK (input)
The dimension of the array WORK. LDWORK >= max(1,N). For
optimum performance LDWORK >= N*NB, where NB is the optimal
blocksize.
If LDWORK = -1, then a workspace query is assumed; the rou‐
tine 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 LDWORK is issued by XERBLA.
INFO (output)
= 0: successful exit
< 0: if INFO = -i, the i-th argument has an illegal value
6 Mar 2009 sorgqr(3P)