Contents
dorgqr - generate an M-by-N real matrix Q with orthonormal
columns,
SUBROUTINE DORGQR(M, N, K, A, LDA, TAU, WORK, LDWORK, INFO)
INTEGER M, N, K, LDA, LDWORK, INFO
DOUBLE PRECISION A(LDA,*), TAU(*), WORK(*)
SUBROUTINE DORGQR_64(M, N, K, A, LDA, TAU, WORK, LDWORK, INFO)
INTEGER*8 M, N, K, LDA, LDWORK, INFO
DOUBLE PRECISION 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(8), DIMENSION(:) :: TAU, WORK
REAL(8), DIMENSION(:,:) :: A
SUBROUTINE ORGQR_64(M, [N], [K], A, [LDA], TAU, [WORK], [LDWORK],
[INFO])
INTEGER(8) :: M, N, K, LDA, LDWORK, INFO
REAL(8), DIMENSION(:) :: TAU, WORK
REAL(8), DIMENSION(:,:) :: A
C INTERFACE
#include <sunperf.h>
void dorgqr(int m, int n, int k, double *a, int lda, double
*tau, int *info);
void dorgqr_64(long m, long n, long k, double *a, long lda,
double *tau, long *info);
dorgqr generates an M-by-N real matrix Q with orthonormal
columns, which is defined as the first N columns of a pro-
duct of K elementary reflectors of order M
Q = H(1) H(2) . . . H(k)
as returned by SGEQRF.
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 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 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 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 LDWORK is issued by XERBLA.
INFO (output)
= 0: successful exit
< 0: if INFO = -i, the i-th argument has an ille-
gal value