Hi all, It seems that my question is very easy one, but I can't find the similar thing...
I know how I can use solution and first derivative solution that comes from fe_values.get_function_values and fe_values.get_function_gradients So I thought that second derivative can be obtained by ///////////////////////////////////////////////////////////////////////////////////// std::vector<Tensor<2,dim> > sol_hess(n_q_points); fe_values.reinit (cell); fe_values.get_function_hessians(solution, sol_hess); ... sol_hess[q_index][0][0] //it is the same as d^2(solution)/dx^2 sol_hess[q_index][1][1] //it is the same as d^2(solution)/dy^2 //////////////////////////////////////////////////////////////////////////////////////////// However, even though the solution is continuous, the plot of d^2(solution)/dx^2 and d^2(solution)/dy^2 look very weird. it looks like set of delta function on the each element. So my question is.. Is it wrong way to get second derivatives of solution?? Thank you. Kyusik. -- 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.
