Provided by: liblapack-doc_3.3.1-1_all

#### NAME

```       LAPACK-3  -  overwrites the general complex m-by-n matrix C with   Q * C if SIDE = 'L' and
TRANS = 'N', or   Q**H* C if SIDE = 'L' and TRANS = 'C', or   C * Q  if  SIDE  =  'R'  and
TRANS = 'N', or   C * Q**H if SIDE = 'R' and TRANS = 'C',

```

#### SYNOPSIS

```       SUBROUTINE ZUNM2L( SIDE, TRANS, M, N, K, A, LDA, TAU, C, LDC, WORK, INFO )

CHARACTER      SIDE, TRANS

INTEGER        INFO, K, LDA, LDC, M, N

COMPLEX*16     A( LDA, * ), C( LDC, * ), TAU( * ), WORK( * )

```

#### PURPOSE

```       ZUNM2L overwrites the general complex m-by-n matrix C with
where Q is a complex unitary matrix defined as the product of k
elementary reflectors
Q = H(k) . . . H(2) H(1)
as returned by ZGEQLF. Q is of order m if SIDE = 'L' and of order n
if SIDE = 'R'.

```

#### ARGUMENTS

```        SIDE    (input) CHARACTER*1
= 'L': apply Q or Q**H from the Left
= 'R': apply Q or Q**H from the Right

TRANS   (input) CHARACTER*1
= 'N': apply Q  (No transpose)
= 'C': apply Q**H (Conjugate transpose)

M       (input) INTEGER
The number of rows of the matrix C. M >= 0.

N       (input) INTEGER
The number of columns of the matrix C. N >= 0.

K       (input) INTEGER
The number of elementary reflectors whose product defines
the matrix Q.
If SIDE = 'L', M >= K >= 0;
if SIDE = 'R', N >= K >= 0.

A       (input) COMPLEX*16 array, dimension (LDA,K)
The i-th column must contain the vector which defines the
elementary reflector H(i), for i = 1,2,...,k, as returned by
ZGEQLF in the last k columns of its array argument A.
A is modified by the routine but restored on exit.

LDA     (input) INTEGER
The leading dimension of the array A.
If SIDE = 'L', LDA >= max(1,M);
if SIDE = 'R', LDA >= max(1,N).

TAU     (input) COMPLEX*16 array, dimension (K)
TAU(i) must contain the scalar factor of the elementary
reflector H(i), as returned by ZGEQLF.

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

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

INFO    (output) INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value

LAPACK routine (version 3.3.1)             April 2011                            ZUNM2L(3lapack)
```