table of contents
/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/cgemqr.f(3) | Library Functions Manual | /home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/cgemqr.f(3) |
NAME¶
/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/cgemqr.f
SYNOPSIS¶
Functions/Subroutines¶
subroutine CGEMQR (side, trans, m, n, k, a, lda, t, tsize,
c, ldc, work, lwork, info)
CGEMQR
Function/Subroutine Documentation¶
subroutine CGEMQR (character side, character trans, integer m, integer n, integer k, complex, dimension( lda, * ) a, integer lda, complex, dimension( * ) t, integer tsize, complex, dimension( ldc, * ) c, integer ldc, complex, dimension( * ) work, integer lwork, integer info)¶
CGEMQR
Purpose:
!> !> CGEMQR overwrites the general real M-by-N matrix C with !> !> SIDE = 'L' SIDE = 'R' !> TRANS = 'N': Q * C C * Q !> TRANS = 'T': Q**H * C C * Q**H !> !> where Q is a complex unitary matrix defined as the product !> of blocked elementary reflectors computed by tall skinny !> QR factorization (CGEQR) !> !>
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': Conjugate transpose, apply Q**H. !>
M
!> M is INTEGER !> The number of rows of the matrix A. 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) !> Part of the data structure to represent Q as returned by CGEQR. !>
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). !>
T
!> T is COMPLEX array, dimension (MAX(5,TSIZE)). !> Part of the data structure to represent Q as returned by CGEQR. !>
TSIZE
!> TSIZE is INTEGER !> The dimension of the array T. TSIZE >= 5. !>
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
!> (workspace) COMPLEX array, dimension (MAX(1,LWORK)) !>
LWORK
!> LWORK is INTEGER !> The dimension of the array WORK. !> 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. !>
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 !> CLATSQR or CGEQRT !> !> Depending on the matrix dimensions M and N, and row and column !> block sizes MB and NB returned by ILAENV, CGEQR will use either !> CLATSQR (if the matrix is tall-and-skinny) or CGEQRT to compute !> the QR factorization. !> This version of CGEMQR will use either CLAMTSQR or CGEMQRT to !> multiply matrix Q by another matrix. !> Further Details in CLAMTSQR or CGEMQRT. !> !>
Definition at line 172 of file cgemqr.f.
Author¶
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Version 3.12.0 | LAPACK |