Hi Michael, I think you should have a look at FE_Q (Lagrange elements) at this link <https://www.dealii.org/current/doxygen/deal.II/classFE__Q.html>. In deal.II, the reference cell's domain is [0,1]^2 for 2d element. So, the point you are about to evaluate (to get the value of phi_i equal 0.25) is (0.5, 0.5). You can refer to this snippet: /* * const FE_Q<2> Q_2d_element(1);* * const Point<2> center(0.5, 0.5);* * for(int i=0; i<Q_2d_element.n_dofs_per_cell(); i++){* * std::cout << Q_2d_element.shape_value(i, center) << std::endl;* * }* */ //output 0.25 0.25 0.25 0.25 Also have a look at step-3 <https://www.dealii.org/current/doxygen/deal.II/step_3.html> to understand how FE_Q works in real problem since the shape functions will be evaluated at real cell coordinates. Good luck.
Regards, T.P Vào lúc 07:48:35 UTC+9 ngày Thứ Bảy, 11 tháng 9, 2021, lian...@gmail.com đã viết: > Deal deal.ii comunity, > > I want to require the value of a shape function at some quadrature point. > But the following code throws an error saying finite_element_output is > protected. > > double shape_value = fe_values.finite_element_output.shape_values(i, q_index); > > For a 2D bilinear element, I expect the shape values at the cell > center(kesi=0, eta=0) are 0.25 for all the 4 shape functions. > [image: Screenshot 2021-09-10 164654.png] > Is there other way to acquire this information? > > Best, > Michael > -- 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/b939b310-fd2b-46ee-83fa-59b46e6f9130n%40googlegroups.com.
