From: Benjamin S. Kirk <benkirk@cf...>  20050513 03:05:41

Maybe the straightforward approach is to use the neighbor information to figure that out. Consider a child element. it has n face neighbors, some of which are siblings, others are from an adjacent element refinement hierarchy. You can loop over all the sides of a child, those neighbors with a different parent are on sides that intersect with parent element sides. All the "internal" sides (sides of the child that do not intersect with a parent's side) will be shared with siblings that have the same parent. So, if ((child>neighbor(s) == NULL) \\ on boundary  (child>neighbor(s)>parent() != child>parent())) then the intersection of parent>side(s) and child>side(s) is not empty As for the node assumption, I'm not positive... You can verify it by checking for the identity rows in the embedding matrix. It suffices to check for the simplest element types, i.e. HEX8 and then it will hold true for all the HEXes. Ben Roy Stogner wrote: > On Wed, 11 May 2005, KIRK, BENJAMIN (JSCEG) (NASA) wrote: > >> That is true. When the intersection of a parent side and child side >> is not >> empty then the two sides are the same number. > > > Okay, then, my only remaining question is "when is the intersection of > a parent side and child side not empty?" > > Yeah, I wish I were kidding. But I'd like to be able to compute this > information (which I'll be adding as Elem::is_child_on_edge() and > Elem::is_child_on_side() ) in advance; the easy implementation of > building both sides and checking for common nodes would add yet more > time to a coarsening projection that already looks unpleasantly slow. > > Would I guess right in assuming that child i shares local vertex > number i with its parent? If that's true, it's enough information for > me to implement all the Tri/Quad/Hex is_child_on_* functions easily, > and I can puzzle through the remaining Tet and Pyramid children from > the embedding matrices. > > Thanks, >  > Roy > > >  > This SF.Net email is sponsored by Oracle Space Sweepstakes > Want to be the first software developer in space? > Enter now for the Oracle Space Sweepstakes! > http://ads.osdn.com/?ad_id=7393&alloc_id=16281&op=click > _______________________________________________ > Libmeshdevel mailing list > Libmeshdevel@... > https://lists.sourceforge.net/lists/listinfo/libmeshdevel 