I found two ways to constrain several dofs (as you mentioned, at least 3 dofs in 2D) for my problem: 1. I can use the "add_line" function, and do not use the "apply_boundary_values" function; or 2 . I can directly modify "std::map<types::global_dof_index, double> boundary_values" and use the "apply_boundary_values" function.

*I wonder if the above two ways are the same in dealii's internal 

They should have the same end result. They may lead to different matrix matrix entries for the constrained degrees of freedom, but should have the same solution.

Furthermore, it is amazing to receive your reply! I have seen most of your lectures on dealii on youtube. These lectures are very very helpful!

Very kind, thank you! But deal.II really is a community project -- I just happen to be the messenger on many occasions.


Wolfgang Bangerth          email:       

The deal.II project is located at
For mailing list/forum options, see
--- 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 
For more options, visit

Reply via email to