CUNMHR(l) ) CUNMHR(l)NAME
CUNMHR - overwrite the general complex M-by-N matrix C with SIDE = 'L'
SIDE = 'R' TRANS = 'N'
SYNOPSIS
SUBROUTINE CUNMHR( SIDE, TRANS, M, N, ILO, IHI, A, LDA, TAU, C, LDC,
WORK, LWORK, INFO )
CHARACTER SIDE, TRANS
INTEGER IHI, ILO, INFO, LDA, LDC, LWORK, M, N
COMPLEX A( LDA, * ), C( LDC, * ), TAU( * ), WORK( * )
PURPOSE
CUNMHR 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 of order nq, with nq = m if SIDE =
'L' and nq = n if SIDE = 'R'. Q is defined as the product of IHI-ILO
elementary reflectors, as returned by CGEHRD:
Q = H(ilo) H(ilo+1) . . . H(ihi-1).
ARGUMENTS
SIDE (input) CHARACTER*1
= 'L': apply Q or Q**H from the Left;
= 'R': apply Q or Q**H from the Right.
TRANS (input) CHARACTER*1
= 'N': apply Q (No transpose)
= 'C': apply Q**H (Conjugate transpose)
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.
ILO (input) INTEGER
IHI (input) INTEGER ILO and IHI must have the same values
as in the previous call of CGEHRD. Q is equal to the unit
matrix except in the submatrix Q(ilo+1:ihi,ilo+1:ihi). If SIDE
= 'L', then 1 <= ILO <= IHI <= M, if M > 0, and ILO = 1 and IHI
= 0, if M = 0; if SIDE = 'R', then 1 <= ILO <= IHI <= N, if N >
0, and ILO = 1 and IHI = 0, if N = 0.
A (input) COMPLEX array, dimension
(LDA,M) if SIDE = 'L' (LDA,N) if SIDE = 'R' The vectors which
define the elementary reflectors, as returned by CGEHRD.
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 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
CGEHRD.
C (input/output) COMPLEX 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 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 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) INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
LAPACK version 3.0 15 June 2000 CUNMHR(l)
