Hi Wolfgang Thanks for your reply. I carefully tested these two methods and found that they produce two different rhs vectors given identical previous solution. There is no non-zero boundary values in my case, and the constrained values are indeed zero. It seems that the unconstrained components in the rhs vector are wrong.
Here is what I suspect: Method 1 uses the stiffness_matrix that has been modified during the assembly, while method 2 is using the original stiffness. Although method 2 will eventually distribute the rhs vector as well as the matrix, it is distributed along with system_matrix, not stiffness_matrix. In the time-dependent simulation, those two are different. I don't know if the modifications to the rhs vector depends on the matrix or not. Thanks Jie -- 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.
