> I am using discontinuous elements on a regular mesh. Given a degree of > freedom that I know lies on a given cell and face (technically has > support on that face, as this is dG) I would like to find out which dof > is its neighbour i.e. the equivalent dof from the cell adjoining across > the given face. > > It is not difficult to loop through all of the cells, then faces then > dofs and find the dofs with support on a given face. It is not > difficult to then extract the neighbouring cell and find which dofs from > that cell also lie on the face. However, what is the best way to find > which dof matches which dof. For example, in 2d using linear dG > elements each face has 2 dofs with support on that face from one cell, > and two from the neighbouring cell. I would like to know how they are > matched so I can add constraints.
If you are using the FE_DGQ class, then shape functions are interpolation polynomials which are associated with interpolation points. We call them support_points in deal.II. You may want to read up on the functions FiniteElement::get_unit_support_points FiniteElement::get_face_unit_support_points and see if that is useful to you -- comparing face support points for two shape functions should allow you to identify the matching ones, together with the things you've already found out so far. Best W. ------------------------------------------------------------------------- Wolfgang Bangerth email: [email protected] www: http://www.math.tamu.edu/~bangerth/ _______________________________________________ dealii mailing list http://poisson.dealii.org/mailman/listinfo/dealii
