Contents
dormrz - overwrite the general real M-by-N matrix C with
SIDE = 'L' SIDE = 'R' TRANS = 'N'
SUBROUTINE DORMRZ(SIDE, TRANS, M, N, K, L, A, LDA, TAU, C, LDC, WORK,
LWORK, INFO)
CHARACTER * 1 SIDE, TRANS
INTEGER M, N, K, L, LDA, LDC, LWORK, INFO
DOUBLE PRECISION A(LDA,*), TAU(*), C(LDC,*), WORK(*)
SUBROUTINE DORMRZ_64(SIDE, TRANS, M, N, K, L, A, LDA, TAU, C, LDC,
WORK, LWORK, INFO)
CHARACTER * 1 SIDE, TRANS
INTEGER*8 M, N, K, L, LDA, LDC, LWORK, INFO
DOUBLE PRECISION A(LDA,*), TAU(*), C(LDC,*), WORK(*)
F95 INTERFACE
SUBROUTINE ORMRZ(SIDE, TRANS, [M], [N], K, L, A, [LDA], TAU, C, [LDC],
[WORK], [LWORK], [INFO])
CHARACTER(LEN=1) :: SIDE, TRANS
INTEGER :: M, N, K, L, LDA, LDC, LWORK, INFO
REAL(8), DIMENSION(:) :: TAU, WORK
REAL(8), DIMENSION(:,:) :: A, C
SUBROUTINE ORMRZ_64(SIDE, TRANS, [M], [N], K, L, A, [LDA], TAU, C,
[LDC], [WORK], [LWORK], [INFO])
CHARACTER(LEN=1) :: SIDE, TRANS
INTEGER(8) :: M, N, K, L, LDA, LDC, LWORK, INFO
REAL(8), DIMENSION(:) :: TAU, WORK
REAL(8), DIMENSION(:,:) :: A, C
C INTERFACE
#include <sunperf.h>
void dormrz(char side, char trans, int m, int n, int k, int
l, double *a, int lda, double *tau, double *c, int
ldc, int *info);
void dormrz_64(char side, char trans, long m, long n, long
k, long l, double *a, long lda, double *tau, dou-
ble *c, long ldc, long *info);
dormrz 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 STZRZF. 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.
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.
L (input) The number of columns of the matrix A containing
the meaningful part of the Householder reflectors.
If SIDE = 'L', M >= L >= 0, if SIDE = 'R', N >= L
>= 0.
A (input) (LDA,M) if SIDE = 'L', (LDA,N) if SIDE = 'R' The
i-th row must contain the vector which defines the
elementary reflector H(i), for i = 1,2,...,k, as
returned by STZRZF in the last k rows of its array
argument A. A is modified by the routine but
restored on exit.
LDA (input)
The leading dimension of the array A. LDA >=
max(1,K).
TAU (input)
TAU(i) must contain the scalar factor of the ele-
mentary reflector H(i), as returned by STZRZF.
C (input/output)
On entry, the M-by-N matrix C. On exit, C is
overwritten by Q*C or Q**H*C or C*Q**H 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
Based on contributions by
A. Petitet, Computer Science Dept., Univ. of Tenn., Knox-
ville, USA