# zlarf.f (3) - Linux Manuals

zlarf.f -

## SYNOPSIS

### Functions/Subroutines

subroutine zlarf (SIDE, M, N, V, INCV, TAU, C, LDC, WORK)
ZLARF applies an elementary reflector to a general rectangular matrix.

## Function/Subroutine Documentation

### subroutine zlarf (characterSIDE, integerM, integerN, complex*16, dimension( * )V, integerINCV, complex*16TAU, complex*16, dimension( ldc, * )C, integerLDC, complex*16, dimension( * )WORK)

ZLARF applies an elementary reflector to a general rectangular matrix.

Purpose:

``` ZLARF 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**H

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

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

To apply H**H, supply conjg(tau) instead
tau.
```

Parameters:

SIDE

```          SIDE is CHARACTER*1
= 'L': form  H * C
= 'R': form  C * H
```

M

```          M is INTEGER
The number of rows of the matrix C.
```

N

```          N is INTEGER
The number of columns of the matrix C.
```

V

```          V is COMPLEX*16 array, dimension
(1 + (M-1)*abs(INCV)) if SIDE = 'L'
or (1 + (N-1)*abs(INCV)) if SIDE = 'R'
The vector v in the representation of H. V is not used if
TAU = 0.
```

INCV

```          INCV is INTEGER
The increment between elements of v. INCV <> 0.
```

TAU

```          TAU is COMPLEX*16
The value tau in the representation of H.
```

C

```          C is 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

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

WORK

```          WORK is COMPLEX*16 array, dimension
(N) if SIDE = 'L'
or (M) if SIDE = 'R'
```

Author:

Univ. of Tennessee

Univ. of California Berkeley