On Wed, 14 Apr 2010, Boyce Griffith wrote: > I am trying to put together a libMesh-based AMR solver which has some > variables I would like to treat as piecewise constants. I think that > the way to do this in libMesh is to set the order to be CONSTANT and the > FE type to be MONOMIAL.
Right. The only question is which system you put them in - the same system as your other variables if they vary and you want them to do so in a fully-coupled way, a separate ImplicitSystem (or subclass) if they vary and you want that variation to be decoupled or one-way coupled, or a separate ExplicitSystem if they are constant (or if they vary in a non-stiff fashion). > When I do this, I get segfaults in EquationSystems::reinit() when > libMesh and my application code are compiled with optimizations enabled. > Similar segfaults do not seem to occur when I compile in debugging > mode even though I am using the same PETSc build in both cases. What version and configuration of PETSc? > The error almost always occurs on process 0 in VecScatterBegin: Yup. > However, this is hard to reproduce. Yes and no. I can't reproduce it with every version of PETSc, but I *can* reproduce it with ex21 of libMesh, even in debugging mode. I'd been hoping that there was just some problem with one of my PETSc builds. But if you're seeing the same bug then odds are it's a bug in libMesh and it's just only triggering segfaults in some PETSc builds. > Am I doing something wrong here? Probably not; if we're both seeing the same problem then I suspect we've got a bug with DG in the SVN head. I'm surprised Lorenzo hasn't run into it first, though. > PS: Tomorrow I am going to work on getting this running with valgrind... I'd appreciate it. Also if you do manage to reproduce the problem in a simple test case, let me know. ex21 is currently hard-coded to use a 3D L-shaped domain, the error doesn't occur until after a few refinement steps, and by that time the size of the send_list (where the problem mostly likely is) is up in the thousands and hard to examine manually. --- Roy ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
