How to set boundary conditions based on mesh information (boundary ids)?
Hey again, I appreciate the simplicity of being able to define boundaries through ufl conditionals as it is done in most dune-fem tutorials. For more sophisticated setups (nontrivial boundary geometries). On the mesh level, I would like to have subsets of my mesh nodes defined as boundaries, identifiable through some name or id, which can then be used to set BCs in my Dune implementation.
This is related to the dune-fem tutorial on boundary conditions "an integer can be provided which can be set to describe a part of the boundary during grid construction as described in another place" , this git issue and the Todo-note here.
The capability is probably there but I couldn't find a nice example on how to do it. Could someone point me to the right tutorial if it exists or briefly post an example? On the mesh side working with gmesh files would be the most flexible option but using the dune mesh format to define boundaries is ok as well.
Thanks
Ben