SRC/clahef_aa.f(3)

NAME
SRC/clahef_aa.f

SYNOPSIS

  Functions/Subroutines
subroutine clahef_aa (uplo, j1, m, nb, a, lda, ipiv, h, ldh, work)
CLAHEF_AA

Function/Subroutine Documentation

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

CLAHEF_AA

Purpose:

     CLAHEF_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 CHETRF_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 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 workspace, dimension (LDH,NB).

    LDH

              LDH is INTEGER
              The leading dimension of the workspace H. LDH >= max(1,M).

    WORK

              WORK is COMPLEX workspace, dimension (M).

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 142 of file clahef_aa.f.

Author

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