# zupmtr.f - Man Page

SRC/zupmtr.f

## Synopsis

### Functions/Subroutines

subroutine zupmtr (side, uplo, trans, m, n, ap, tau, c, ldc, work, info)
ZUPMTR

## Function/Subroutine Documentation

### subroutine zupmtr (character side, character uplo, character trans, integer m, integer n, complex*16, dimension( * ) ap, complex*16, dimension( * ) tau, complex*16, dimension( ldc, * ) c, integer ldc, complex*16, dimension( * ) work, integer info)

ZUPMTR

Purpose:

``` ZUPMTR 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
nq-1 elementary reflectors, as returned by ZHPTRD using packed
storage:

if UPLO = 'U', Q = H(nq-1) . . . H(2) H(1);

if UPLO = 'L', Q = H(1) H(2) . . . H(nq-1).```
Parameters

SIDE

```          SIDE is CHARACTER*1
= 'L': apply Q or Q**H from the Left;
= 'R': apply Q or Q**H from the Right.```

UPLO

```          UPLO is CHARACTER*1
= 'U': Upper triangular packed storage used in previous
call to ZHPTRD;
= 'L': Lower triangular packed storage used in previous
call to ZHPTRD.```

TRANS

```          TRANS is CHARACTER*1
= 'N':  No transpose, apply Q;
= 'C':  Conjugate transpose, apply Q**H.```

M

```          M is INTEGER
The number of rows of the matrix C. M >= 0.```

N

```          N is INTEGER
The number of columns of the matrix C. N >= 0.```

AP

```          AP is COMPLEX*16 array, dimension
(M*(M+1)/2) if SIDE = 'L'
(N*(N+1)/2) if SIDE = 'R'
The vectors which define the elementary reflectors, as
returned by ZHPTRD.  AP is modified by the routine but
restored on exit.```

TAU

```          TAU is COMPLEX*16 array, dimension (M-1) if SIDE = 'L'
or (N-1) if SIDE = 'R'
TAU(i) must contain the scalar factor of the elementary
reflector H(i), as returned by ZHPTRD.```

C

```          C is COMPLEX*16 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

```          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'
(M) if SIDE = 'R'```

INFO

```          INFO is INTEGER
= 0:  successful exit
< 0:  if INFO = -i, the i-th argument had an illegal value```
Author

Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Definition at line 148 of file zupmtr.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

The man page zupmtr(3) is an alias of zupmtr.f(3).

Tue Nov 28 2023 12:08:42 Version 3.12.0 LAPACK