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RedHat 9 (Linux i386) - man page for zlaed0 (redhat section l)

ZLAED0(l)					)					ZLAED0(l)

NAME
       ZLAED0  -  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 Her-
       mitian matrix and corresponding eigenvectors of the dense or band matrix

SYNOPSIS
       SUBROUTINE ZLAED0( QSIZ, N, D, E, Q, LDQ, QSTORE, LDQS, RWORK, IWORK, INFO )

	   INTEGER	  INFO, LDQ, LDQS, N, QSIZ

	   INTEGER	  IWORK( * )

	   DOUBLE	  PRECISION D( * ), E( * ), RWORK( * )

	   COMPLEX*16	  Q( LDQ, * ), QSTORE( LDQS, * )

PURPOSE
       Using the divide and conquer method, ZLAED0 computes all eigenvalues of a symmetric tridi-
       agonal 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.

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

       N      (input) INTEGER
	      The dimension of the symmetric tridiagonal matrix.  N >= 0.

       D      (input/output) DOUBLE PRECISION array, dimension (N)
	      On entry, the diagonal elements of the tridiagonal matrix.  On exit, the	eigenval-
	      ues in ascending order.

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

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

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

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

       INFO   (output) 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).

LAPACK version 3.0			   15 June 2000 				ZLAED0(l)


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