Hello Onno, I just tried running your code but see that I can't because I don't have the rectmesh.msh. Might you be able to send that so we can see exactly what you see? Francis P.S. I would also be curious to see the gmsh file that generated the msh file if possible. ------------------ Francis Poulin Associate Professor Department of Applied Mathematics University of Waterloo email: fpoulin@uwaterloo.ca Web: https://uwaterloo.ca/poulin-research-group/ Telephone: +1 519 888 4567 x32637 ________________________________ From: firedrake-bounces@imperial.ac.uk [firedrake-bounces@imperial.ac.uk] on behalf of Onno Bokhove [O.Bokhove@leeds.ac.uk] Sent: Saturday, June 25, 2016 11:05 AM To: firedrake Subject: [firedrake] upwind example remark; extension to CN in time Hi FDs, (i) The upwind example is odd in that the real boundaries are treated in a special way rather than setting the outside value in the same numerical flux as anywhere else; my question is how this can be fixed? So no special terms at the in- and outflow, just specify the outside velocity used. This is imo the proper DG way not was is done now. (ii) Attached my attempt to do a time dependent advection with Crank Nicolson, which works but does not yet give the right answer, in part due to (i). [I don't understand why I have to make my theta variable that a constant but other wise it did not work.] Any suggestions, corrections, also on other silly things done by me? Next step is to extend to system with 3 equations; hence the few extra but unused variables. Thanks, from midnight Seoul in old style Korean guesthouse. Onno ________________________________