A couple of things: 1. -pre is just an option for that particular example. It was an attempt to provide a solver agnostic way of turning on preconditioning. If you don't specify -pre or a petsc option to turn on preconditioning then you are doing zero preconditioning... which is bound to fail.
2. To specify to petsc that you want to turn on preconditioned jacobian free newton krylov (P-JFNK) use -snes_mf_operator on the command-line (this is what -pre does in that example). Use this in conjunction with your LU options and you will have better luck ;-) Derek On Thu, Mar 7, 2013 at 10:33 AM, John Peterson <[email protected]> wrote: > > > > On Thu, Mar 7, 2013 at 9:31 AM, Subramanya Gautam Sadasiva < > [email protected]> wrote: > >> Yes, that is right... my bad.. >> > > > Nevertheless, I think you are correct that there is *something* wrong with > his Jacobian. Maybe it's "good enough" to work with non-direct solvers but > fails on LU? > > -- > John > ------------------------------------------------------------------------------ Symantec Endpoint Protection 12 positioned as A LEADER in The Forrester Wave(TM): Endpoint Security, Q1 2013 and "remains a good choice" in the endpoint security space. For insight on selecting the right partner to tackle endpoint security challenges, access the full report. http://p.sf.net/sfu/symantec-dev2dev _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
