Hi all, I am playing with a vector-valued 2D problem (displacement vector u and v). Since I need to use the shape functions of a specific vertex, I export the DOFs numbering and its corresponding number of the vertex. As illustrated in FiniteElement <https://www.dealii.org/current/doxygen/deal.II/group__fe.html>, for quadratic 2D FE_Q element, the pair of DODs of a specific vertex are grouped as follows:
#DOF, #component, #within the base 0 0 0 1 1 0 2 0 1 3 1 1 4 0 2 5 1 2 6 0 3 7 1 3 8 0 4 9 1 4 10 0 5 11 1 5 12 0 6 13 1 6 14 0 7 15 1 7 16 0 8 17 1 8 However, for high-order elements (higher than or equal to 3), this pattern no longer exists. In other words, the DOFs of the same vertex are not grouped. Take 4th order 2D FE_Q as an example, #DOF, #component, #within the base 0 0 0 1 1 0 2 0 1 3 1 1 4 0 2 5 1 2 6 0 3 7 1 3 8 0 4 9 0 5 10 0 6 11 1 4 12 1 5 13 1 6 14 0 7 15 0 8 16 0 9 17 1 7 18 1 8 19 1 9 20 0 10 21 0 11 22 0 12 23 1 10 24 1 11 25 1 12 26 0 13 27 0 14 28 0 15 29 1 13 30 1 14 31 1 15 32 0 16 33 0 17 34 0 18 35 0 19 36 0 20 37 0 21 38 0 22 39 0 23 40 0 24 41 1 16 42 1 17 43 1 18 44 1 19 45 1 20 46 1 21 47 1 22 48 1 23 49 1 24 I guess this suggests that we cannot simply assume the pairing of DOFs in vector-valued problems. My question is, is the numbering of the DOF is fixed among the same type of elements? Since I need to fetch the DOFs of a specific vertex, I guess FiniteElement::component_to_system_index() can help determine the current DOF number of a specific vertex. Do I need to check them for each element? or just check it once for a certain type of element? Regards, Lixing -- 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 [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/dealii/26a04f52-2766-442c-ae99-00589fda8612n%40googlegroups.com.
