Derek, My Jacobian is very much unsymmetric and so I am curious based on what Roy suggests. If the BoomerAMG does not work with unsymmetric systems, this could be a problem.
When you get back, please do detail on your findings and I would be very much interested to know about your experiences. Thanks. Vijay > -----Original Message----- > From: Roy Stogner [mailto:[EMAIL PROTECTED] > Sent: Friday, November 07, 2008 9:48 PM > To: Derek Gaston > Cc: [email protected] > Subject: Re: [Libmesh-users] Multigrid techniques with libmesh > > > On Fri, 7 Nov 2008, Derek Gaston wrote: > > > The answer to #2 is YES... We use Hypre with BoomerAMG to precondition > > our matrix free solves all the time. Just build petsc with Hypre > > support and pass the following on the command-line for your app: > > > > -snes_mf_operator -pc_type hypre -pc_hypre_type boomeramg > > > > This will use AMG on whatever you put into the jacobian matrix and use > > the result to precondition your matrix free solve. > > Wait - run that by me again? > > "matrix free solves" ... "use AMG on whatever you put into the > jacobian matrix" ... > > Wouldn't that make it an "AMG free solve"? > > But seriously, how is AMG possible without a matrix to work with? > > Also: do you have BoomerAMG working on asymmetric problems? It was > giving us real trouble (like, converging to the wrong result trouble) > a couple years back when we tried to use it on a problem with an > asymmetric jacobian. > --- > Roy > > ------------------------------------------------------------------------- > This SF.Net email is sponsored by the Moblin Your Move Developer's > challenge > Build the coolest Linux based applications with Moblin SDK & win great > prizes > Grand prize is a trip for two to an Open Source event anywhere in the > world > http://moblin-contest.org/redirect.php?banner_id=100&url=/ > _______________________________________________ > Libmesh-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/libmesh-users ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
