SRC/zlahef_aa.f(3) | Library Functions Manual | SRC/zlahef_aa.f(3) |
NAME
SRC/zlahef_aa.f
SYNOPSIS
Functions/Subroutines
subroutine zlahef_aa (uplo, j1, m, nb, a, lda, ipiv, h,
ldh, work)
ZLAHEF_AA
Function/Subroutine Documentation
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
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
UPLO
UPLO is CHARACTER*1 = 'U': Upper triangle of A is stored; = 'L': Lower triangle of A is stored.
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.
M
M is INTEGER The dimension of the submatrix. M >= 0.
NB
NB is INTEGER The dimension of the panel to be facotorized.
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.
LDA
LDA is INTEGER The leading dimension of the array A. LDA >= max(1,N).
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).
H
H is COMPLEX*16 workspace, dimension (LDH,NB).
LDH
LDH is INTEGER The leading dimension of the workspace H. LDH >= max(1,M).
WORK
WORK is COMPLEX*16 workspace, dimension (M).
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Definition at line 142 of file zlahef_aa.f.
Author
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