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.

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