NAME
zunmtr - overwrite the general complex M-by-N matrix C with
SIDE = 'L' SIDE = 'R' TRANS = 'N'
SYNOPSIS
SUBROUTINE ZUNMTR( SIDE, UPLO, TRANS, M, N, A, LDA, TAU, C,
LDC, WORK, LWORK, INFO )
CHARACTER SIDE, TRANS, UPLO
INTEGER INFO, LDA, LDC, LWORK, M, N
COMPLEX*16 A( LDA, * ), C( LDC, * ), TAU( * ), WORK( LWORK )
#include <sunperf.h>
void zunmtr(char side, char uplo, char trans, int m, int n,
doublecomplex *za, int lda, doublecomplex *tau,
doublecomplex *zc, int ldc, int *info) ;
PURPOSE
ZUNMTR overwrites the general complex M-by-N matrix C with
TRANS = 'C': Q**H * C C * Q**H
where Q is a complex unitary matrix of order nq, with nq = m
if SIDE = 'L' and nq = n if SIDE = 'R'. Q is defined as the
product of nq-1 elementary reflectors, as returned by
ZHETRD:
if UPLO = 'U', Q = H(nq-1) . . . H(2) H(1);
if UPLO = 'L', Q = H(1) H(2) . . . H(nq-1).
ARGUMENTS
SIDE (input) CHARACTER*1
= 'L': apply Q or Q**H from the Left;
= 'R': apply Q or Q**H from the Right.
UPLO (input) CHARACTER*1
= 'U': Upper triangle of A contains elementary
reflectors from ZHETRD; = 'L': Lower triangle of A
contains elementary reflectors from ZHETRD.
TRANS (input) CHARACTER*1
= 'N': No transpose, apply Q;
= 'C': Conjugate transpose, apply Q**H.
M (input) INTEGER
The number of rows of the matrix C. M >= 0.
N (input) INTEGER
The number of columns of the matrix C. N >= 0.
A (input) COMPLEX*16 array, dimension
(LDA,M) if SIDE = 'L' (LDA,N) if SIDE = 'R' The
vectors which define the elementary reflectors, as
returned by ZHETRD.
LDA (input) INTEGER
The leading dimension of the array A. LDA >=
max(1,M) if SIDE = 'L'; LDA >= max(1,N) if SIDE =
'R'.
TAU (input) COMPLEX*16 array, dimension
(M-1) if SIDE = 'L' (N-1) if SIDE = 'R' TAU(i)
must contain the scalar factor of the elementary
reflector H(i), as returned by ZHETRD.
C (input/output) COMPLEX*16 array, dimension (LDC,N)
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) INTEGER
The leading dimension of the array C. LDC >=
max(1,M).
WORK (workspace/output) COMPLEX*16 array, dimension
(LWORK)
On exit, if INFO = 0, WORK(1) returns the optimal
LWORK.
LWORK (input) INTEGER
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.
INFO (output) INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an ille-
gal value
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