I haven't looked at that problem and don't know much about curl-curl spaces... but if the matrix would respond to multigrid at all I highly recommend compiling PETSc with Hypre support and using:
-pc_type hypre -pc_hypre_type boomeramg For problems where it works it can't be beat... Derek On Thu, Sep 13, 2012 at 2:30 PM, Roy Stogner <[email protected]>wrote: > > My favorite preconditioner has always been ILU4 (wrapped in block > Jacobi in parallel), and that's worked well enough that except for a > couple applications I've never bothered trying to do better. > > Now I'm discovering that ILU4 fails horribly on our little old > vector_fe_ex3 (curl-curl) example. I have no idea why one step of ILU > converges in a hundred-odd iterations and four steps doesn't make it > to square root of tolerance after 5000 iterations, but clearly I need > new LIBMESH_OPTIONS. > > Any suggestions? > --- > Roy > > > ------------------------------------------------------------------------------ > Live Security Virtual Conference > Exclusive live event will cover all the ways today's security and > threat landscape has changed and how IT managers can respond. Discussions > will include endpoint security, mobile security and the latest in malware > threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ > _______________________________________________ > Libmesh-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/libmesh-users > ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
