dormrz(3P) Sun Performance Library dormrz(3P)NAMEdormrz - overwrite the general real M-by-N matrix C with Q*C or Q**H*C
or C*Q**H or C*Q.
SYNOPSIS
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, double *c, long ldc, long
*info);
PURPOSEdormrz overwrites the general real M-by-N matrix C with
SIDE = 'L' SIDE = 'R'
TRANS = 'N': Q * C C * Q
TRANS = 'T': Q**T * C C * Q**T
where Q is a real orthogonal matrix defined as the product of k elemen‐
tary reflectors
Q = H(1)H(2) . . . H(k)
as returned by DTZRZF. Q is of order M if SIDE = 'L' and of order N if
SIDE = 'R'.
ARGUMENTS
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 meaning‐
ful 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 reflec‐
tor H(i), for i = 1,2,...,k, as returned by DTZRZF 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 elementary
reflector H(i), as returned by DTZRZF.
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 per‐
formance 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 illegal value
FURTHER DETAILS
Based on contributions by
A. Petitet, Computer Science Dept., Univ. of Tenn., Knoxville, USA
6 Mar 2009 dormrz(3P)
