Contents
dormqr - overwrite the general real M-by-N matrix C with
SIDE = 'L' SIDE = 'R' TRANS = 'N'
SUBROUTINE DORMQR(SIDE, TRANS, M, N, K, A, LDA, TAU, C, LDC, WORK,
LWORK, INFO)
CHARACTER * 1 SIDE, TRANS
INTEGER M, N, K, LDA, LDC, LWORK, INFO
DOUBLE PRECISION A(LDA,*), TAU(*), C(LDC,*), WORK(*)
SUBROUTINE DORMQR_64(SIDE, TRANS, M, N, K, A, LDA, TAU, C, LDC, WORK,
LWORK, INFO)
CHARACTER * 1 SIDE, TRANS
INTEGER*8 M, N, K, LDA, LDC, LWORK, INFO
DOUBLE PRECISION A(LDA,*), TAU(*), C(LDC,*), WORK(*)
F95 INTERFACE
SUBROUTINE ORMQR(SIDE, [TRANS], [M], [N], [K], A, [LDA], TAU, C, [LDC],
[WORK], [LWORK], [INFO])
CHARACTER(LEN=1) :: SIDE, TRANS
INTEGER :: M, N, K, LDA, LDC, LWORK, INFO
REAL(8), DIMENSION(:) :: TAU, WORK
REAL(8), DIMENSION(:,:) :: A, C
SUBROUTINE ORMQR_64(SIDE, [TRANS], [M], [N], [K], A, [LDA], TAU, C,
[LDC], [WORK], [LWORK], [INFO])
CHARACTER(LEN=1) :: SIDE, TRANS
INTEGER(8) :: M, N, K, LDA, LDC, LWORK, INFO
REAL(8), DIMENSION(:) :: TAU, WORK
REAL(8), DIMENSION(:,:) :: A, C
C INTERFACE
#include <sunperf.h>
void dormqr(char side, char trans, int m, int n, int k, dou-
ble *a, int lda, double *tau, double *c, int ldc,
int *info);
void dormqr_64(char side, char trans, long m, long n, long
k, double *a, long lda, double *tau, double *c,
long ldc, long *info);
dormqr overwrites the general real M-by-N matrix C with
TRANS = 'T': Q**T * C C * Q**T
where Q is a real orthogonal matrix defined as the product
of k elementary reflectors
Q = H(1) H(2) . . . H(k)
as returned by SGEQRF. Q is of order M if SIDE = 'L' and of
order N if SIDE = 'R'.
SIDE (input)
= 'L': apply Q or Q**T from the Left;
= 'R': apply Q or Q**T from the Right.
TRANS (input)
= 'N': No transpose, apply Q;
= 'T': Transpose, apply Q**T.
TRANS is defaulted to 'N' for F95 INTERFACE.
M (input) The number of rows of the matrix C. M >= 0.
N (input) The number of columns of the matrix C. N >= 0.
K (input) The number of elementary reflectors whose product
defines the matrix Q. If SIDE = 'L', M >= K >= 0;
if SIDE = 'R', N >= K >= 0.
A (input) 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. A is modified by
the routine but restored on exit.
LDA (input)
The leading dimension of the array A. If SIDE =
'L', LDA >= max(1,M); if SIDE = 'R', LDA >=
max(1,N).
TAU (input)
TAU(i) must contain the scalar factor of the ele-
mentary reflector H(i), as returned by SGEQRF.
C (input/output)
On entry, the M-by-N matrix C. On exit, C is
overwritten by Q*C or Q**T*C or C*Q**T or C*Q.
LDC (input)
The leading dimension of the array C. LDC >=
max(1,M).
WORK (workspace)
On exit, if INFO = 0, WORK(1) returns the optimal
LWORK.
LWORK (input)
The dimension of the array WORK. If SIDE = 'L',
LWORK >= max(1,N); if SIDE = 'R', LWORK >=
max(1,M). For optimum performance LWORK >= N*NB
if SIDE = 'L', and LWORK >= M*NB if SIDE = 'R',
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 had an ille-
gal value