LAPACK 3.12.0
LAPACK: Linear Algebra PACKage
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◆ zgemlq()

subroutine zgemlq ( character side,
character trans,
integer m,
integer n,
integer k,
complex*16, dimension( lda, * ) a,
integer lda,
complex*16, dimension( * ) t,
integer tsize,
complex*16, dimension( ldc, * ) c,
integer ldc,
complex*16, dimension( * ) work,
integer lwork,
integer info )

ZGEMLQ

Purpose:
!>
!>     ZGEMLQ overwrites the general real 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 blocked elementary reflectors computed by short wide
!>      LQ factorization (ZGELQ)
!>
!> 
Parameters
[in]SIDE
!>          SIDE is CHARACTER*1
!>          = 'L': apply Q or Q**H from the Left;
!>          = 'R': apply Q or Q**H from the Right.
!> 
[in]TRANS
!>          TRANS is CHARACTER*1
!>          = 'N':  No transpose, apply Q;
!>          = 'C':  Conjugate transpose, apply Q**H.
!> 
[in]M
!>          M is INTEGER
!>          The number of rows of the matrix A.  M >=0.
!> 
[in]N
!>          N is INTEGER
!>          The number of columns of the matrix C. N >= 0.
!> 
[in]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.
!>
!> 
[in]A
!>          A is COMPLEX*16 array, dimension
!>                               (LDA,M) if SIDE = 'L',
!>                               (LDA,N) if SIDE = 'R'
!>          Part of the data structure to represent Q as returned by ZGELQ.
!> 
[in]LDA
!>          LDA is INTEGER
!>          The leading dimension of the array A. LDA >= max(1,K).
!> 
[in]T
!>          T is COMPLEX*16 array, dimension (MAX(5,TSIZE)).
!>          Part of the data structure to represent Q as returned by ZGELQ.
!> 
[in]TSIZE
!>          TSIZE is INTEGER
!>          The dimension of the array T. TSIZE >= 5.
!> 
[in,out]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.
!> 
[in]LDC
!>          LDC is INTEGER
!>          The leading dimension of the array C. LDC >= max(1,M).
!> 
[out]WORK
!>          (workspace) COMPLEX*16 array, dimension (MAX(1,LWORK))
!>          On exit, if INFO = 0, WORK(1) returns the minimal LWORK.
!> 
[in]LWORK
!>          LWORK is INTEGER
!>          The dimension of the array WORK. LWORK >= 1.
!>          If LWORK = -1, then a workspace query is assumed. The routine
!>          only calculates the size of the WORK array, returns this
!>          value as WORK(1), and no error message related to WORK
!>          is issued by XERBLA.
!> 
[out]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.
Further Details
!>
!> These details are particular for this LAPACK implementation. Users should not
!> take them for granted. These details may change in the future, and are not likely
!> true for another LAPACK implementation. These details are relevant if one wants
!> to try to understand the code. They are not part of the interface.
!>
!> In this version,
!>
!>          T(2): row block size (MB)
!>          T(3): column block size (NB)
!>          T(6:TSIZE): data structure needed for Q, computed by
!>                           ZLASWLQ or ZGELQT
!>
!>  Depending on the matrix dimensions M and N, and row and column
!>  block sizes MB and NB returned by ILAENV, ZGELQ will use either
!>  ZLASWLQ (if the matrix is wide-and-short) or ZGELQT to compute
!>  the LQ factorization.
!>  This version of ZGEMLQ will use either ZLAMSWLQ or ZGEMLQT to
!>  multiply matrix Q by another matrix.
!>  Further Details in ZLAMSWLQ or ZGEMLQT.
!>