Hello Deal.ii Friends, I want to set 2 constraints (P = 0 and \delta P = 0) on the scalar pressure variable on a single point (4, 0.1) at the outlet. Here, \delta P is the Newton's iteration update value for P.
I used "constraints_hp_nonzero" to interpolate the real boundary values for my physical problem and "constraints_newton_boundary" to interpolate the Newton updates values on the boundaries. I found that one can only set one type of constraint on a singel index. Therefore, the following snippet code would generate errors, since I was trying to set 2 different constraints simultaneously on the same dof index. Point<dim> point(4.0, 0.1); std::set<unsigned int> constrained_dofs; const unsigned int pressure_component = extractor_stokes_pressure.component; for (const auto &cell : dof_handler.active_cell_iterators()) { if (cell->is_locally_owned() ) { for (unsigned int v=0; v<GeometryInfo<dim>::vertices_per_cell; ++v) { if (cell->vertex(v).distance(point) < 1e-8) { // get the index unsigned int dof_index = cell->vertex_dof_index(v, pressure_component); if (constrained_dofs.find(dof_index) == constrained_dofs.end()) { pcout << "index" << dof_index << std::endl; //constraints_newton_boundary.add_line(dof_index); constraints_hp_nonzero.add_line(dof_index); constrained_dofs.insert(dof_index); } } } } } Back to my problem. If I want to successfully impose the 2 constraints: P=0 and delta P=0 on point (4,0.1), does it exist a better way? Could you kindly give me some hints? I appreciate any reply to my question here. Regards, Lee -- The deal.II project is located at http://www.dealii.org/ For mailing list/forum options, see https://groups.google.com/d/forum/dealii?hl=en --- You received this message because you are subscribed to the Google Groups "deal.II User Group" group. To unsubscribe from this group and stop receiving emails from it, send an email to dealii+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/dealii/259ea4a1-edab-451a-82c4-31f514e0ed5dn%40googlegroups.com.