Hi Ilya, I am not away of principally simple solution, the RHS simply contains your bilinear form times interpolated values at constrained DoFs. What you can do is to loop over a subset of cells (those which are at the boundary), still assemble the local matrix and do constraints.distribute_local_to_global() which takes global matrix and RHS.
Or you can use constrained_linear_operator <https://www.dealii.org/developer/doxygen/deal.II/group__constraints.html#ga59c2f70370213d436cb9fade9d813478>, see this <https://groups.google.com/d/msg/dealii/A8dQs5i2n8A/YotvqvGwEgAJ> forum discussion. Please also study this <https://groups.google.com/d/msg/dealii/xo3Fa_olNwM/ObOuJPP2JT0J> thread, which covers similar question. Regards, Denis. On Tuesday, February 20, 2018 at 4:46:19 PM UTC+1, Bryukhanov Ilya wrote: > > Hi, > > I consider elastic problem and forces and displacements on boundaries are > changing with time. I don't want to compute FEM matrix > on each step. How to correctly simulate the task? I know that there is a > simple solution, but my solution is incorrect :) > I have two variables for the system_matrix and rhs_vector. I try to > recompute rhs_vector on each step and dirichlet condition > is accounted by calling "intepolate_boundary values + > apply_boundary_values" on each step with system_matrix and rhs_vector > variables inside. > I think that I should use initial matrix and the matrix which is modified > by Dirichlet procedure and assign latter to the initial matrix on each step? > Am I corrent or there is some other solution? > > > > > > > -- 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.
