Perform tests to decide whether the symmetric tridiagonal matrix T
 warrants expensive computations which guarantee high relative accuracy
 in the eigenvalues.

N

          N is INTEGER
          The order of the matrix. N > 0.

D

          D is REAL array, dimension (N)
          The N diagonal elements of the tridiagonal matrix T.

E

          E is REAL array, dimension (N)
          On entry, the first (N-1) entries contain the subdiagonal
          elements of the tridiagonal matrix T; E(N) is set to ZERO.

INFO

          INFO is INTEGER
          INFO = 0(default) : the matrix warrants computations preserving
                              relative accuracy.
          INFO = 1          : the matrix warrants computations guaranteeing
                              only absolute accuracy.

Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd.

November 2011

Beresford Parlett, University of California, Berkeley, USA
Jim Demmel, University of California, Berkeley, USA
Inderjit Dhillon, University of Texas, Austin, USA
Osni Marques, LBNL/NERSC, USA
Christof Voemel, University of California, Berkeley, USA