On Tue, Mar 23, 2010 at 2:41 PM, Roy Stogner <[email protected]> wrote: > > On Tue, 23 Mar 2010, John Peterson wrote: > >> Roy: Is my memory correct in that this is the same "perfectly >> unnested" element (with respect to h-refinement) we looked at for >> shallow water equations a while back? > > You're thinking of the P1-NC "P1 Non-Conforming" element, right? No, > that one was simpler in some ways (only 1 dof per edge, instead of 1 > per edge and 1 per vertex, and it was linear on the whole element with > no subelements) and horribly more complex (did we *ever* figure out > the right way to do hanging node refinement with it?) in others. > > This one's a plain C0 element, 6 nodes on triangles, Lagrange basis; > the distinction from our LAGRANGE quadratic is that the function space > is linear on each of the 4 subelements rather than a quadratic on the > whole element. > > You're right that it's a lower-order element; I don't recall what the > advantage over P1/P0 is supposed to be.
P1/P0 is not LBB-stable. Gresho & Sani also say "sometimes locks" and "rarely, if ever, usable." Ouch. iso P2 - P1 on the other hand, is LBB-stable. -- John ------------------------------------------------------------------------------ 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
