DSTEV(l)	     LAPACK driver routine (version 1.1)	     DSTEV(l)

NAME
  DSTEV	- compute all eigenvalues and, optionally, eigenvectors	of a real
  symmetric tridiagonal	matrix A

SYNOPSIS

  SUBROUTINE DSTEV( JOBZ, N, D,	E, Z, LDZ, WORK, INFO )

      CHARACTER	    JOBZ

      INTEGER	    INFO, LDZ, N

      DOUBLE	    PRECISION D( * ), E( * ), WORK( * ), Z( LDZ, * )

PURPOSE
  DSTEV	computes all eigenvalues and, optionally, eigenvectors of a real sym-
  metric tridiagonal matrix A.

ARGUMENTS

  JOBZ	  (input) CHARACTER*1
	  = 'N':  Compute eigenvalues only;
	  = 'V':  Compute eigenvalues and eigenvectors.

  N	  (input) INTEGER
	  The order of the matrix.  N >= 0.

  D	  (input/output) DOUBLE	PRECISION array, dimension (N)
	  On entry, the	n diagonal elements of the tridiagonal matrix A.  On
	  exit,	if INFO	= 0, the eigenvalues in	ascending order.

  E	  (input/workspace) DOUBLE PRECISION array, dimension (N)
	  On entry, the	(n-1) subdiagonal elements of the tridiagonal matrix
	  A, stored in elements	1 to N-1 of E; E(N) need not be	set, but is
	  used by the routine.	On exit, the contents of E are destroyed.

  Z	  (output) DOUBLE PRECISION array, dimension (LDZ, N)
	  If JOBZ = 'V', then if INFO =	0, Z contains the orthonormal eigen-
	  vectors of the matrix	A, with	the i-th column	of Z holding the
	  eigenvector associated with D(i).  If	JOBZ = 'N', then Z is not
	  referenced.

  LDZ	  (input) INTEGER
	  The leading dimension	of the array Z.	 LDZ >=	1, and if JOBZ = 'V',
	  LDZ >= max(1,N).

  WORK	  (workspace) DOUBLE PRECISION array, dimension	(max(1,2*N-2))
	  If JOBZ = 'N', WORK is not referenced.

  INFO	  (output) INTEGER
	  = 0:	successful exit
	  < 0:	if INFO	= -i, the i-th argument	had an illegal value
	  > 0:	if INFO	= i, the algorithm failed to converge; i off-diagonal
	  elements of E	did not	converge to zero.