zlahef_aa()

subroutine zlahef_aa	(	character	uplo,
		integer	j1,
		integer	m,
		integer	nb,
		complex*16, dimension( lda, * )	a,
		integer	lda,
		integer, dimension( * )	ipiv,
		complex*16, dimension( ldh, * )	h,
		integer	ldh,
		complex*16, dimension( * )	work )

ZLAHEF_AA

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Purpose:

!>
!> DLAHEF_AA factorizes a panel of a complex hermitian matrix A using
!> the Aasen's algorithm. The panel consists of a set of NB rows of A
!> when UPLO is U, or a set of NB columns when UPLO is L.
!>
!> In order to factorize the panel, the Aasen's algorithm requires the
!> last row, or column, of the previous panel. The first row, or column,
!> of A is set to be the first row, or column, of an identity matrix,
!> which is used to factorize the first panel.
!>
!> The resulting J-th row of U, or J-th column of L, is stored in the
!> (J-1)-th row, or column, of A (without the unit diagonals), while
!> the diagonal and subdiagonal of A are overwritten by those of T.
!>
!> 

Parameters

[in]	UPLO	!> UPLO is CHARACTER*1 !> = 'U': Upper triangle of A is stored; !> = 'L': Lower triangle of A is stored. !>
[in]	J1	!> J1 is INTEGER !> The location of the first row, or column, of the panel !> within the submatrix of A, passed to this routine, e.g., !> when called by ZHETRF_AA, for the first panel, J1 is 1, !> while for the remaining panels, J1 is 2. !>
[in]	M	!> M is INTEGER !> The dimension of the submatrix. M >= 0. !>
[in]	NB	!> NB is INTEGER !> The dimension of the panel to be facotorized. !>
[in,out]	A	!> A is COMPLEX*16 array, dimension (LDA,M) for !> the first panel, while dimension (LDA,M+1) for the !> remaining panels. !> !> On entry, A contains the last row, or column, of !> the previous panel, and the trailing submatrix of A !> to be factorized, except for the first panel, only !> the panel is passed. !> !> On exit, the leading panel is factorized. !>
[in]	LDA	!> LDA is INTEGER !> The leading dimension of the array A. LDA >= max(1,N). !>
[out]	IPIV	!> IPIV is INTEGER array, dimension (N) !> Details of the row and column interchanges, !> the row and column k were interchanged with the row and !> column IPIV(k). !>
[in,out]	H	!> H is COMPLEX*16 workspace, dimension (LDH,NB). !> !>
[in]	LDH	!> LDH is INTEGER !> The leading dimension of the workspace H. LDH >= max(1,M). !>
[out]	WORK	!> WORK is COMPLEX*16 workspace, dimension (M). !>

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.