RST(3F)

NAME
     RST, SRST     -  EISPACK routine.  This subroutine calls the recommended
     sequence of subroutines from the eigensystem subroutine package (EISPACK)
     to find the eigenvalues and eigenvectors (if desired) of a REAL SYMMETRIC
     TRIDIAGONAL matrix.


SYNOPSYS
          subroutine  rst(nm, n, w, e, matz, z, ierr)
          integer          nm, n, matz, ierr
          double precision w(n), e(n), z(nm,n)

          subroutine srst(nm, n, w, e, matz, z, ierr)
          integer          nm, n, matz, ierr
          real             w(n), e(n), z(nm,n)



DESCRIPTION
     On Input

     NM must be set to the row dimension of the two-dimensional array
     parameters as declared in the calling program dimension statement.

     N is the order of the matrix.

     W contains the diagonal elements of the real symmetric tridiagonal
     matrix.

     E contains the subdiagonal elements of the matrix in its last N-1
     POSITIONS.  E(1) is arbitrary.

     MATZ is an integer variable set equal to zero if only eigenvalues are
     desired.  Otherwise it is set to any non-zero integer for both
     eigenvalues and eigenvectors.  On Output

     W contains the eigenvalues in ascending order.

     Z contains the eigenvectors if MATZ is not zero.

     IERR is an integer output variable set equal to an error completion code
     described in section 2B of the documentation.  The normal completion code
     is zero.  Questions and comments should be directed to B. S. Garbow,
     APPLIED MATHEMATICS DIVISION, ARGONNE NATIONAL LABORATORY