# dlatzm (3) - Linux Man Pages

dlatzm.f -

## SYNOPSIS

### Functions/Subroutines

subroutine dlatzm (SIDE, M, N, V, INCV, TAU, C1, C2, LDC, WORK)
DLATZM

## Function/Subroutine Documentation

### subroutine dlatzm (characterSIDE, integerM, integerN, double precision, dimension( * )V, integerINCV, double precisionTAU, double precision, dimension( ldc, * )C1, double precision, dimension( ldc, * )C2, integerLDC, double precision, dimension( * )WORK)

DLATZM

Purpose:

``` This routine is deprecated and has been replaced by routine DORMRZ.

DLATZM applies a Householder matrix generated by DTZRQF to a matrix.

Let P = I - tau*u*u**T,   u = ( 1 ),
( v )
where v is an (m-1) vector if SIDE = 'L', or a (n-1) vector if
SIDE = 'R'.

If SIDE equals 'L', let
C = [ C1 ] 1
[ C2 ] m-1
n
Then C is overwritten by P*C.

If SIDE equals 'R', let
C = [ C1, C2 ] m
1  n-1
Then C is overwritten by C*P.
```

Parameters:

SIDE

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

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

INCV

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

TAU

```          TAU is DOUBLE PRECISION
The value tau in the representation of P.
```

C1

```          C1 is DOUBLE PRECISION array, dimension
(LDC,N) if SIDE = 'L'
(M,1)   if SIDE = 'R'
On entry, the n-vector C1 if SIDE = 'L', or the m-vector C1
if SIDE = 'R'.

On exit, the first row of P*C if SIDE = 'L', or the first
column of C*P if SIDE = 'R'.
```

C2

```          C2 is DOUBLE PRECISION array, dimension
(LDC, N)   if SIDE = 'L'
(LDC, N-1) if SIDE = 'R'
On entry, the (m - 1) x n matrix C2 if SIDE = 'L', or the
m x (n - 1) matrix C2 if SIDE = 'R'.

On exit, rows 2:m of P*C if SIDE = 'L', or columns 2:m of C*P
if SIDE = 'R'.
```

LDC

```          LDC is INTEGER
The leading dimension of the arrays C1 and C2. LDC >= (1,M).
```

WORK

```          WORK is DOUBLE PRECISION array, dimension
(N) if SIDE = 'L'
(M) if SIDE = 'R'
```

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

November 2011

Definition at line 152 of file dlatzm.f.

## Author

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