On Wed, 2011-07-13 at 14:18 +0200, Markus Bürg wrote: > Hello Johannes, > > > As I understand it at the moment, for FEM functions are represented as a > > sum of basis functions multiplied by coefficients. These basis functions > > have a compact support, which is (for the case of FE_Q) one or more > > cells in the triangulation, depending whether the corresponding dof sits > > on a vertex, a face or a cell. The basis functions are in some way > > ordered and numbered by a index. When I wrote "value of a dof", I wanted > > to refer to the coefficient of the corresponding basis function (which > > is the integral of the shape function when I want to represent the > > constant function 1), not its index. > > > No, this is wrong. For simple Lagrangian elements the degrees of > freedom, and thus the coefficients you are looking for, are defined as > the point evaluation of the function (in your case the constant function > 1) at the support point of the dof.
That is interesting. I never thought about it this way, but I have the feeling that the point evaluation at the support point of the dof is equivalent to the integral over the corresponding basis function. Thank you > > Best Regards, > Markus > _______________________________________________ > dealii mailing list http://poisson.dealii.org/mailman/listinfo/dealii _______________________________________________ dealii mailing list http://poisson.dealii.org/mailman/listinfo/dealii
