Bruno, Thank you for your prompt reply! I found that I forget to add other boundary conditions, and in this case the stiffness matrix is in fact singular. >From my understanding, if I want to constrain a dof "i" to zero, instead of adding a constraint of dofs "i, j, k, ...", I may only need the add_line function. For my problem, I think more tests need to be excuted to check if the effect of add_line function is equivalent to that of modifying the boundary_values directly.
Thank you very much! Best, Pai -- 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.
