On Wed, 5 Sep 2012, Paul T. Bauman wrote: > I wanted to solicit ideas and discussion for designs handling the > edge/face orientation and element order. In particular, for scalar > Lagrange elements of order >= 3 (and other scalar elements) or > oriented vector elements (e.g. Nedelec), the orientation of the > element matters
Orientation ends up important for us for anything where we end up having more than one DoF supported on an edge or face. I think that's *everything* of order 3+, except for the C1 elements, where in one sense orientation matters immediately but in another sense it doesn't start mattering until you get into quartics or quintics. > and must be taken into account to ensure continuity of the solution. > Right now, this is handled on a case-by-case basis in the hierarchic > elements and the nedelec elements, but we ought to be able to do > better. In particular, for 3-D, higher order, the face orientation > handling is going to be ugly (I think). For sure, even > the edge orientation for the hexes and tets will be a bit long > winded and it would be nice to have that in one place. Agreed, if that's possible. > My thinking is that such an FEOrientation (other suggestions for > names?) function (object?) should return a scaling factor (either 1 > or -1 ) that depends on the geometric element and finite element > type and order and then each finite element class can call as > needed. Scaling factor isn't enough in general, though. It works for the hierarchics and nedelecs, but for high-order Lagrange you'd need to "reshuffle" local->global degree of freedom indexing too. And I don't think the scaling factors for the hierarchics match the ones for the nedelecs. > 3. Implement an edge (and face in 3D) orientation function within > each geometric element type that returns the scaling factor and then > have each finite element type worry about the element order scaling > factor. This sounds ideal, if it could be made to owrk. --- Roy ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Libmesh-devel mailing list Libmesh-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libmesh-devel
