cunmql.f −

**Functions/Subroutines**

subroutine **cunmql** (SIDE, TRANS, M, N, K, A, LDA, TAU, C, LDC, WORK, LWORK, INFO)

CUNMQL

**subroutine cunmql (characterSIDE, characterTRANS, integerM, integerN, integerK, complex, dimension( lda, * )A, integerLDA, complex, dimension( * )TAU, complex, dimension( ldc, * )C, integerLDC, complex, dimension( * )WORK, integerLWORK, integerINFO)
CUNMQL**

**Purpose:**

CUNMQL 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 defined as the product of k

elementary reflectors

as returned by CGEQLF. Q is of order M if SIDE = ’L’ and of order N

if SIDE = ’R’.

**Parameters:**

*SIDE*

SIDE is CHARACTER*1

= ’L’: apply Q or Q**H from the Left;

= ’R’: apply Q or Q**H from the Right.

*TRANS*

TRANS is CHARACTER*1

= ’N’: No transpose, apply Q;

= ’C’: 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.

*K*

K is 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*

A is COMPLEX 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

CGEQLF in the last k columns of its array argument A.

*LDA*

LDA is INTEGER

The leading dimension of the array A.

If SIDE = ’L’, LDA >= max(1,M);

if SIDE = ’R’, LDA >= max(1,N).

*TAU*

TAU is COMPLEX array, dimension (K)

TAU(i) must contain the scalar factor of the elementary

reflector H(i), as returned by CGEQLF.

*C*

C is COMPLEX 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 array, dimension (MAX(1,LWORK))

On exit, if INFO = 0, WORK(1) returns the optimal LWORK.

*LWORK*

LWORK is INTEGER

The dimension of the array WORK.

If SIDE = ’L’, LWORK >= max(1,N);

if SIDE = ’R’, LWORK >= max(1,M).

For optimum performance LWORK >= N*NB if SIDE = ’L’, and

LWORK >= M*NB if SIDE = ’R’, where NB is the optimal

blocksize.

If LWORK = -1, then a workspace query is assumed; the routine

only calculates the optimal size of the WORK array, returns

this value as the first entry of the WORK array, and no error

message related to LWORK is issued by XERBLA.

*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

Univ. of Colorado Denver

NAG Ltd.

**Date:**

November 2011

Definition at line 170 of file cunmql.f.

Generated automatically by Doxygen for LAPACK from the source code.