On Mon, Jun 2, 2008 at 11:17 AM, Roy Stogner <[EMAIL PROTECTED]> wrote: > > On Mon, 2 Jun 2008, Derek Gaston wrote: > >> On Jun 2, 2008, at 9:45 AM, Roy Stogner wrote: >> >> What advantages does FEMSystem have over using Ben's >> NonlinearImplicit system stuff using SNES? I've used both, but I >> don't really see the difference. > > For you, since the numerical jacobians aren't useful right now, one of > the biggest advantages is gone. But having the time integration > factored out is nice for transient problems, and the interior_, side_, > etc. helper methods are nice for nonlinear problems. But the biggest
Just wanted to mention: not having to write for loops over elements and element sides is a big benefit for me. You also don't have an opportunity to forget to constrain the element matrix and vector before inserting it into the system matrix. > remaining benefits are still "to be written", I think. Threaded > assembly (without having to write your own weird TBB code) should be a > nice feature, even if we'll have to go through an API change to get > there. And there are some other niceties (bubble-function based > physics-dependent error estimators, for example) that can really only > be implemented if the library can request residuals of one element at > a time. > >> For us, we're using the NonlinearImplicit system because we hope to fill out >> the Trilinos interfaces at some point and use NOX instead... > > Is something wrong with the FEMSystem->SNES interface? I admit that I > basically gave up on PetscDiffSolver when it turned out that my own > quasi-Newton code was faster on my apps, but there's at least a place > there to start. If you're doing matrix-free work, the fact that > DiffSystem currently inherits from ImplicitSystem may be a stumbling > block, but NonlinearImplicitSystem has the same problem. > --- > Roy > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Microsoft > Defy all challenges. Microsoft(R) Visual Studio 2008. > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > _______________________________________________ > Libmesh-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/libmesh-users > ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
