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# LAPACK-3

## man page of LAPACK-3

### LAPACK-3: applies a complex elementary reflector H to a complex m by n matrix C, from either the left or the right

```NAME
LAPACK-3 - applies a complex elementary reflector H to a complex m by n
matrix C, from either the left or the right

SYNOPSIS
SUBROUTINE ZLARFX( SIDE, M, N, V, TAU, C, LDC, WORK )

IMPLICIT       NONE

CHARACTER      SIDE

INTEGER        LDC, M, N

COMPLEX*16     TAU

COMPLEX*16     C( LDC, * ), V( * ), WORK( * )

PURPOSE
ZLARFX 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
H = I - tau * v * v'
where tau is a complex scalar and v is a complex vector.
If tau = 0, then H is taken to be the unit matrix
This version uses inline code if H has order < 11.

ARGUMENTS
SIDE    (input) CHARACTER*1
= 'L': form  H * C
= 'R': form  C * H

M       (input) INTEGER
The number of rows of the matrix C.

N       (input) INTEGER
The number of columns of the matrix C.

V       (input) COMPLEX*16 array, dimension (M) if SIDE = 'L'
or (N) if SIDE = 'R'
The vector v in the representation of H.

TAU     (input) COMPLEX*16
The value tau in the representation of H.

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'.

LDC     (input) INTEGER
The leading dimension of the array C. LDA >= max(1,M).

WORK    (workspace) COMPLEX*16 array, dimension (N) if SIDE = 'L'
or (M) if SIDE = 'R'
WORK is not referenced if H has order < 11.

LAPACK auxiliary routine (versionMarch 2011                       LAPACK-3(3)
```