.TH ZLARZ l "15 June 2000" "LAPACK version 3.0" ")"
.SH NAME
ZLARZ - applie a complex elementary reflector H to a complex M-by-N matrix C, from either the left or the right
.SH SYNOPSIS
.TP 18
SUBROUTINE ZLARZ(
SIDE, M, N, L, V, INCV, TAU, C, LDC, WORK )
.TP 18
.ti +4
CHARACTER
SIDE
.TP 18
.ti +4
INTEGER
INCV, L, LDC, M, N
.TP 18
.ti +4
COMPLEX*16
TAU
.TP 18
.ti +4
COMPLEX*16
C( LDC, * ), V( * ), WORK( * )
.SH PURPOSE
ZLARZ applies a complex elementary reflector H to a complex M-by-N matrix C, from either the left or the right. H is represented in the form
.br

      H = I - tau * v * v'
.br

where tau is a complex scalar and v is a complex vector.
.br

If tau = 0, then H is taken to be the unit matrix.
.br

To apply H' (the conjugate transpose of H), supply conjg(tau) instead
tau.
.br

H is a product of k elementary reflectors as returned by ZTZRZF.

.SH ARGUMENTS
.TP 8
SIDE    (input) CHARACTER*1
= 'L': form  H * C
.br
= 'R': form  C * H
.TP 8
M       (input) INTEGER
The number of rows of the matrix C.
.TP 8
N       (input) INTEGER
The number of columns of the matrix C.
.TP 8
L       (input) INTEGER
The number of entries of the vector V containing
the meaningful part of the Householder vectors.
If SIDE = 'L', M >= L >= 0, if SIDE = 'R', N >= L >= 0.
.TP 8
V       (input) COMPLEX*16 array, dimension (1+(L-1)*abs(INCV))
The vector v in the representation of H as returned by
ZTZRZF. V is not used if TAU = 0.
.TP 8
INCV    (input) INTEGER
The increment between elements of v. INCV <> 0.
.TP 8
TAU     (input) COMPLEX*16
The value tau in the representation of H.
.TP 8
C       (input/output) COMPLEX*16 array, dimension (LDC,N)
On entry, the M-by-N matrix C.
On exit, C is overwritten by the matrix H * C if SIDE = 'L',
or C * H if SIDE = 'R'.
.TP 8
LDC     (input) INTEGER
The leading dimension of the array C. LDC >= max(1,M).
.TP 8
WORK    (workspace) COMPLEX*16 array, dimension
(N) if SIDE = 'L'
or (M) if SIDE = 'R'
.SH FURTHER DETAILS
Based on contributions by
.br
  A. Petitet, Computer Science Dept., Univ. of Tenn., Knoxville, USA