zlaed0.f(3)

NAME
zlaed0.f -

SYNOPSIS

  Functions/Subroutines
subroutine ZLAED0 (QSIZ, N, D, E, Q, LDQ, QSTORE, LDQS, RWORK, IWORK, INFO)
ZLAED0

Function/Subroutine Documentation

  subroutine ZLAED0 (INTEGERQSIZ, INTEGERN, DOUBLE PRECISION, dimension( * )D, DOUBLE PRECISION, dimension( * )E, COMPLEX*16, dimension( ldq, * )Q, INTEGERLDQ, COMPLEX*16, dimension( ldqs, * )QSTORE, INTEGERLDQS, DOUBLE PRECISION, dimension( * )RWORK, INTEGER, dimension( * )IWORK, INTEGERINFO)

ZLAED0

Purpose:

     Using the divide and conquer method, ZLAED0 computes all eigenvalues
     of a symmetric tridiagonal matrix which is one diagonal block of
     those from reducing a dense or band Hermitian matrix and
     corresponding eigenvectors of the dense or band matrix.

Parameters:
    QSIZ

              QSIZ is INTEGER
             The dimension of the unitary matrix used to reduce
             the full matrix to tridiagonal form.  QSIZ >= N if ICOMPQ = 1.

    N

              N is INTEGER
             The dimension of the symmetric tridiagonal matrix.  N >= 0.

    D

              D is DOUBLE PRECISION array, dimension (N)
             On entry, the diagonal elements of the tridiagonal matrix.
             On exit, the eigenvalues in ascending order.

    E

              E is DOUBLE PRECISION array, dimension (N-1)
             On entry, the off-diagonal elements of the tridiagonal matrix.
             On exit, E has been destroyed.

    Q

              Q is COMPLEX*16 array, dimension (LDQ,N)
             On entry, Q must contain an QSIZ x N matrix whose columns
             unitarily orthonormal. It is a part of the unitary matrix
             that reduces the full dense Hermitian matrix to a
             (reducible) symmetric tridiagonal matrix.

    LDQ

              LDQ is INTEGER
             The leading dimension of the array Q.  LDQ >= max(1,N).

    IWORK

              IWORK is INTEGER array,
             the dimension of IWORK must be at least
                          6 + 6*N + 5*N*lg N
                          ( lg( N ) = smallest integer k
                                      such that 2^k >= N )

    RWORK

              RWORK is DOUBLE PRECISION array,
                                   dimension (1 + 3*N + 2*N*lg N + 3*N**2)
                            ( lg( N ) = smallest integer k
                                        such that 2^k >= N )

    QSTORE

              QSTORE is COMPLEX*16 array, dimension (LDQS, N)
             Used to store parts of
             the eigenvector matrix when the updating matrix multiplies
             take place.

    LDQS

              LDQS is INTEGER
             The leading dimension of the array QSTORE.
             LDQS >= max(1,N).

    INFO

              INFO is INTEGER
              = 0:  successful exit.
              < 0:  if INFO = -i, the i-th argument had an illegal value.
              > 0:  The algorithm failed to compute an eigenvalue while
                    working on the submatrix lying in rows and columns
                    INFO/(N+1) through mod(INFO,N+1).

Author:
    Univ'. of Tennessee

    Univ'. of California Berkeley

    Univ'. of Colorado Denver

    NAG Ltd'.

Date:
    November 2011

Definition at line 145 of file zlaed0.f'.

Author

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