[Trilinos-Users] AztecOO restarted gmres

C.S. Natarajan csnataraj at gmail.com
Fri Jan 29 14:55:31 EST 2016

Hi Danielle, Not an expert but I think in Aztec, restart is the same as
number of Krylov vectors retained for the ls problem (so, 250 in your
case). If you have enough memory probably no harm in setting it to maxiter,
gmres w/o restart is optimal.

*From:* Trilinos-Users [mailto:trilinos-users-bounces at trilinos.org] *On
Behalf Of *Danielle Catherine Maddix
*Sent:* Friday, January 29, 2016 10:13 AM
*To:* trilinos-users at trilinos.org
*Subject:* [Trilinos-Users] AztecOO restarted gmres


I am solving a non-symmetric indefinite PDE problem arising from PDEs. When
use gmres_condnum, it encouraged me to increase the dimension of the Krylov
space. So I increased it from the default 30 to 250 using the kspace
AZ_option. I am also seeing better results using MGS rather than CGS. I was
wondering if there was a way to also specify the number of restarts that we
want or if that is done internally when the maximum number of iterations is


Danielle Maddix
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://trilinos.org/pipermail/trilinos-users/attachments/20160129/05dfd790/attachment.html>

More information about the Trilinos-Users mailing list