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[Anders Logg <question107349@xxxxxxxxxxxxxxxxxxxxx>]

Question #107349 on DOLFIN changed:
https://answers.launchpad.net/dolfin/+question/107349

Anders Logg proposed the following answer:
On Wed, Apr 14, 2010 at 11:50:36AM +0200, Anders Logg wrote:
> On Wed, Apr 14, 2010 at 09:33:20AM -0000, Garth Wells wrote:
> > Question #107349 on DOLFIN changed:
> > https://answers.launchpad.net/dolfin/+question/107349
> >
> > Garth Wells proposed the following answer:
> >
> > On 14/04/10 17:17, Anders Logg wrote:
> > > On Wed, Apr 14, 2010 at 07:17:44AM -0000, bluejerry wrote:
> > >> New question #107349 on DOLFIN:
> > >> https://answers.launchpad.net/dolfin/+question/107349
> > >>
> > >> Is it possible to receive some sorf of error feedback when a solution did not converge while using the Krylov solver. A warning is printed by the PETsc solver that it did not converge, but I can't seem to find a way to detect this programatically. The solve method returns a Function even if the solver did not converge.
> > >>
> > >> Thank you
> > >>
> > >> Renier
> > >
> > > We had a similar problem with the Newton solver last week. It didn't
> > > converge but we thought it did.
> > >
> > > I would also like to see an error when the solver doesn't converge.
> > >
> >
> > Just an error is bad. Presently, a warning message is printed, but we
> > can add a parameter to switch between error/warning.
>
> Sounds good. I think it should be set to error by default with the
> possibility to change it to a warning. That is safest for first time
> users. Someone with a little more experience would check for
> convergence and have a strategy for handling the case where things
> don't converge (change of parameters, time step etc).

Done. The parameter name is "error_on_nonconvergence".

--
Anders

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