Dear all,
I am solving a 3x3 block system arising form DG time discretisation of the semilinear parabolic equations in the form u_t - \Delta u = f(u) for the block solution vector U which consists from three nodal values blocks U0, U1 and U2. During the solution process I need just the solution values of the second block U1 at the previous time steps (t_{n-1}, t_{n-2} and t_{n-3}) i.e. old_solution.block(1), old_old_solution.block(1) and old_old_old_solution.block(1) for this task I used std::vector<Vector<double> old_solution_values (n_q_points, Vector<double>(3)); std::vector<Vector<double> old_solution_values0 (n_q_points, Vector<double>(3)); std::vector<Vector<double> old_solution_values1 (n_q_points, Vector<double>(3)); fe_values.get_function_values (old_solution, old_solution_values); fe_values.get_function_values (old_old_solution, old_solution_values0); fe_values.get_function_values (old_old_old_solution, old_solution_values1); In the solution process in the right hand side assembly I need just the nodal values of second block U1 at the previous time steps (t_{n-1}, t_{n-2} and t_{n-3}) i.e. old_solution.block(1) For this reason, I used const double old_s = old_solution_values[q_point](1); const double old_s = old_solution_values0[q_point](1); const double old_s = old_solution_values1[q_point](1); but I did not get required results and even when I changed old_solution_values[q_point](1) to old_solution_values[q_point](0) nothing has changed (just to check if there is any difference) and even when I tried the wrong thing old_solution.block(1) nothing has changed and I got the same results as with previous other cases. I am confused about this case; did I do some thing wrong in defining the nodal values of the second block of the solution vector at the previous time steps? Any feedbacks and hints are appreciated. Best regards Mohammad Sabawi -- 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. For more options, visit https://groups.google.com/d/optout.