On Mon, 18 Feb 2008, Benjamin Kirk wrote: > I guess it depends on what you mean by a 'mesh.' I can easily conceive of a > single mesh which meets your needs. It can contain overlapping elements of > different types if need be, and of different sizes. You would want to use > the element subdomain flag or something like that to associate a set of > elements with a set of physics, but the point is that all the elements for > the multiple sets of physics lie in the same 'mesh.' > > This would require some work in the DofMap to allocate dofs only to a subset > of the active elements, but that is do-able.
We could get DofMap to allocate certain dofs only to certain elements, yes: we'd been thinking of using the p refinement level as a way of handling transient element deletions/recreations for certain problems, and using an optional per-variable flag instead would work just as well. But that's not quite the whole of it; in the staggered grids situation, there's also the question of getting the sparsity pattern right when none of the elements in one grid are neighbors of elements in the other. Could you share QUAD9 nodes such that an interior node on one grid is a vertex node in the other? That'll probably work okay on uniform grids with the Lagrange basis, but try and do anything fancier like hierarchics or adaptive h-refinement and I'll bet a dozen assert() statements (or worse, hidden assumptions) in the library start failing. --- 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
