zunmrz(3P) Sun Performance Library zunmrz(3P)NAMEzunmrz - overwrite the general complex M-by-N matrix C with Q*C or
Q**H*C or C*Q**H or C*Q.
SYNOPSIS
SUBROUTINE ZUNMRZ(SIDE, TRANS, M, N, K, L, A, LDA, TAU, C, LDC, WORK,
LWORK, INFO)
CHARACTER * 1 SIDE, TRANS
DOUBLE COMPLEX A(LDA,*), TAU(*), C(LDC,*), WORK(*)
INTEGER M, N, K, L, LDA, LDC, LWORK, INFO
SUBROUTINE ZUNMRZ_64(SIDE, TRANS, M, N, K, L, A, LDA, TAU, C, LDC,
WORK, LWORK, INFO)
CHARACTER * 1 SIDE, TRANS
DOUBLE COMPLEX A(LDA,*), TAU(*), C(LDC,*), WORK(*)
INTEGER*8 M, N, K, L, LDA, LDC, LWORK, INFO
F95 INTERFACE
SUBROUTINE ZUNMRZ(SIDE, TRANS, M, N, K, L, A, LDA, TAU, C, LDC,
WORK, LWORK, INFO)
CHARACTER(LEN=1) :: SIDE, TRANS
COMPLEX(8), DIMENSION(:) :: TAU, WORK
COMPLEX(8), DIMENSION(:,:) :: A, C
INTEGER :: M, N, K, L, LDA, LDC, LWORK, INFO
SUBROUTINE ZUNMRZ_64(SIDE, TRANS, M, N, K, L, A, LDA, TAU, C, LDC,
WORK, LWORK, INFO)
CHARACTER(LEN=1) :: SIDE, TRANS
COMPLEX(8), DIMENSION(:) :: TAU, WORK
COMPLEX(8), DIMENSION(:,:) :: A, C
INTEGER(8) :: M, N, K, L, LDA, LDC, LWORK, INFO
C INTERFACE
#include <sunperf.h>
void zunmrz(char side, char trans, int m, int n, int k, int l, double‐
complex *a, int lda, doublecomplex *tau, doublecomplex *c,
int ldc, int *info);
void zunmrz_64(char side, char trans, long m, long n, long k, long l,
doublecomplex *a, long lda, doublecomplex *tau, doublecomplex
*c, long ldc, long *info);
PURPOSEzunmrz overwrites the general complex M-by-N matrix C with
SIDE = 'L' SIDE = 'R'
TRANS = 'N': Q * C C * Q
TRANS = 'C': Q**H * C C * Q**H
where Q is a complex unitary matrix defined as the product of k elemen‐
tary reflectors
Q = H(1)H(2) . . . H(k)
as returned by ZTZRZF. Q is of order M if SIDE = 'L' and of order N if
SIDE = 'R'.
ARGUMENTS
SIDE (input)
= 'L': apply Q or Q**H from the Left;
= 'R': apply Q or Q**H from the Right.
TRANS (input)
= 'N': No transpose, apply Q;
= 'C': Conjugate transpose, apply Q**H.
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 ZTZRZF 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 ZTZRZF.
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 zunmrz(3P)
