DLARRR
November 2006
Purpose
Perform tests to decide whether the symmetric tridiagonal matrix T
warrants expensive computations which guarantee high relative accuracy
in the eigenvalues.
warrants expensive computations which guarantee high relative accuracy
in the eigenvalues.
Arguments
| N |
(input) INTEGER
The order of the matrix. N > 0.
|
| D |
(input) DOUBLE PRECISION array, dimension (N)
The N diagonal elements of the tridiagonal matrix T.
|
| E |
(input/output) DOUBLE PRECISION 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 |
(output) INTEGER
INFO = 0(default) : the matrix warrants computations preserving
relative accuracy. INFO = 1 : the matrix warrants computations guaranteeing only absolute accuracy. |
Further Details
Based on contributions by
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
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