On Sat, 5 Jun 2010, Wolfgang Bangerth wrote:
It still might be related to the hanging nodes, because the same method is used to read the mesh in whether your use dg or normal. I believe that the method used to read the mesh does not support hanging nodes. I.e. if you have a cell refined further than its neighbors it will have a node on the face of its neighbors and I don't think this is supported when the mesh is read.
Please EMail me some of the problem mesh files. I have been trying to develop code to handle complex boundaries. This includes more than one "hole" and holes that may have different properties or materials, including anisotropic. [email protected]
Indeed, and the GridIn class in fact says so: ............................. Since the coarse mesh fed into a @p Triangulation object cannot have hanging nodes, strange things will happen if the input file has them. This is due to the fact that most mesh description formats do not store neighborship information between cells, so the grid reading functions have to regenerate it. They do so by checking whether two cells have a common face. If there are hanging nodes in a triangulation, adjacent cells have no common (complete) face, so the grid reader concludes that the adjacent cells have no neighbors along these faces and must therefore be at the boundary. In effect, an internal crack of the domain is introduced this way. Since such cases are very hard to detect, the library does not make any attempt to abort on such situations, and you will get a triangulation that probably does not do what you want. ............................. This is a frequently asked question, so if anyone has suggestions on how to improve this text I'd be happy to change it! Best W.
The text is fine. We may be able to develop the code to extract the intended geometry in a usable form. Fallback would be to ask the user for specific additional information. Jon Squire [email protected] _______________________________________________ dealii mailing list http://poisson.dealii.org/mailman/listinfo/dealii
