zunmbr()

subroutine zunmbr	(	character	vect,
		character	side,
		character	trans,
		integer	m,
		integer	n,
		integer	k,
		complex*16, dimension( lda, * )	a,
		integer	lda,
		complex*16, dimension( * )	tau,
		complex*16, dimension( ldc, * )	c,
		integer	ldc,
		complex*16, dimension( * )	work,
		integer	lwork,
		integer	info )

ZUNMBR

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Purpose:

!>
!> If VECT = 'Q', ZUNMBR 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
!>
!> If VECT = 'P', ZUNMBR overwrites the general complex M-by-N matrix C
!> with
!>                 SIDE = 'L'     SIDE = 'R'
!> TRANS = 'N':      P * C          C * P
!> TRANS = 'C':      P**H * C       C * P**H
!>
!> Here Q and P**H are the unitary matrices determined by ZGEBRD when
!> reducing a complex matrix A to bidiagonal form: A = Q * B * P**H. Q
!> and P**H are defined as products of elementary reflectors H(i) and
!> G(i) respectively.
!>
!> Let nq = m if SIDE = 'L' and nq = n if SIDE = 'R'. Thus nq is the
!> order of the unitary matrix Q or P**H that is applied.
!>
!> If VECT = 'Q', A is assumed to have been an NQ-by-K matrix:
!> if nq >= k, Q = H(1) H(2) . . . H(k);
!> if nq < k, Q = H(1) H(2) . . . H(nq-1).
!>
!> If VECT = 'P', A is assumed to have been a K-by-NQ matrix:
!> if k < nq, P = G(1) G(2) . . . G(k);
!> if k >= nq, P = G(1) G(2) . . . G(nq-1).
!> 

Parameters

[in]	VECT	!> VECT is CHARACTER*1 !> = 'Q': apply Q or Q**H; !> = 'P': apply P or P**H. !>
[in]	SIDE	!> SIDE is CHARACTER*1 !> = 'L': apply Q, Q**H, P or P**H from the Left; !> = 'R': apply Q, Q**H, P or P**H from the Right. !>
[in]	TRANS	!> TRANS is CHARACTER*1 !> = 'N': No transpose, apply Q or P; !> = 'C': Conjugate transpose, apply Q**H or P**H. !>
[in]	M	!> M is INTEGER !> The number of rows of the matrix C. M >= 0. !>
[in]	N	!> N is INTEGER !> The number of columns of the matrix C. N >= 0. !>
[in]	K	!> K is INTEGER !> If VECT = 'Q', the number of columns in the original !> matrix reduced by ZGEBRD. !> If VECT = 'P', the number of rows in the original !> matrix reduced by ZGEBRD. !> K >= 0. !>
[in]	A	!> A is COMPLEX*16 array, dimension !> (LDA,min(nq,K)) if VECT = 'Q' !> (LDA,nq) if VECT = 'P' !> The vectors which define the elementary reflectors H(i) and !> G(i), whose products determine the matrices Q and P, as !> returned by ZGEBRD. !>
[in]	LDA	!> LDA is INTEGER !> The leading dimension of the array A. !> If VECT = 'Q', LDA >= max(1,nq); !> if VECT = 'P', LDA >= max(1,min(nq,K)). !>
[in]	TAU	!> TAU is COMPLEX*16 array, dimension (min(nq,K)) !> TAU(i) must contain the scalar factor of the elementary !> reflector H(i) or G(i) which determines Q or P, as returned !> by ZGEBRD in the array argument TAUQ or TAUP. !>
[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 !> or P*C or P**H*C or C*P or C*P**H. !>
[in]	LDC	!> LDC is INTEGER !> The leading dimension of the array C. LDC >= max(1,M). !>
[out]	WORK	!> WORK is COMPLEX*16 array, dimension (MAX(1,LWORK)) !> On exit, if INFO = 0, WORK(1) returns the optimal LWORK. !>
[in]	LWORK	!> LWORK is INTEGER !> The dimension of the array WORK. !> If SIDE = 'L', LWORK >= max(1,N); !> if SIDE = 'R', LWORK >= max(1,M); !> if N = 0 or M = 0, LWORK >= 1. !> For optimum performance LWORK >= max(1,N*NB) if SIDE = 'L', !> and LWORK >= max(1,M*NB) if SIDE = 'R', where NB is the !> optimal blocksize. (NB = 0 if M = 0 or N = 0.) !> !> 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. !>
[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.