> I have modified the old version of step-12 (the pre-MeshWorker > variant) to determine the order of accuracy for the DG solver (on > uniform meshes). I am using piecewise quadratics and 4-point Gaussian > quadratures in the DG transport equation solver. I coded up the exact > solution (a simple, smooth function u = sin(2pi x) cos (2pi y)) and > modified the RHS and boundary conditions accordingly (and > double-checked everything for bugs/errors). The L2/L^\infty error > norms are computed in DGMethod<dim>::process_solution using 7-point > quadratures. In the end, the order of convergence that I am seeing is > only 1.5, instead of the 2nd order convergence that I was expecting.
Not knowing much about the issue, but it's worth asking: Can one expect to get full order of convergence for the hyperbolic transport equation? My recollection was that, for example, using the streamline upwind method for this equation only yields order 1.5 as well. (This recollection may be entirely wrong, I just wanted to bring up the fundamental question.) W. _______________________________________________ dealii mailing list http://poisson.dealii.org/mailman/listinfo/dealii
