From: robert <robert.bodner@un...>  20101208 15:54:36

Hi, I have tried to modify example code 9. I am using a starting concentration of one everywhere but want to set the condition for one (or more) boundary to zero. for (unsigned int qp=0; qp<qface.n_points(); qp++) { //const Number value = exact_solution (qface_points[qp](0), // qface_points[qp](1), // time); // RHS contribution for (unsigned int i=0; i<psi.size(); i++) Fe(i) += 0.;//penalty*JxW_face[qp]*value*psi[i][qp]; // Matrix contribution for (unsigned int i=0; i<psi.size(); i++) for (unsigned int j=0; j<psi.size(); j++) Ke(i,j) += penalty*JxW_face[qp]*psi[i][qp]*psi[j][qp]; } Well, at the boundaries I get the values which I want to have. However, I also get strong oscillations. I have also tried to just put the initial concentration to zero for a small region within the domain. Again, I got oscillations (but less intense). What am I doing wrong here? thanks, Robert 