SSTERF(3)                  MathKeisan LAPACK routine                 SSTERF(3)



NAME
       SSTERF  -  all  eigenvalues of a symmetric tridiagonal matrix using the
       Pal-Walker-Kahan variant of the QL or QR algorithm

SYNOPSIS
       SUBROUTINE SSTERF( N, D, E, INFO )

           INTEGER        INFO, N

           REAL           D( * ), E( * )

PURPOSE
       SSTERF computes all eigenvalues of a symmetric tridiagonal matrix using
       the Pal-Walker-Kahan variant of the QL or QR algorithm.


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

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

       E       (input/output) REAL array, dimension (N-1)
               On entry, the (n-1) subdiagonal  elements  of  the  tridiagonal
               matrix.  On exit, E has been destroyed.

       INFO    (output) INTEGER
               = 0:  successful exit
               < 0:  if INFO = -i, the i-th argument had an illegal value
               >  0:  the algorithm failed to find all of the eigenvalues in a
               total of 30*N iterations; if INFO = i, then  i  elements  of  E
               have not converged to zero.



 LAPACK routine (version 3.1)    November 2006                       SSTERF(3)