To add to what Wolfgang already said, there’s also the constrained_linear_operator() <https://dealii.org/developer/doxygen/deal.II/group__constraints.html#ga4787b401a7e601750d85b8b4fc84c8a5> that may be of use in this scenario.
Best, Jean-Paul > On 25 Sep 2020, at 23:29, Wolfgang Bangerth <bange...@colostate.edu> wrote: > > On 9/25/20 3:07 PM, Xuefeng Li wrote: >> My question is: will the repeated call to function apply_boundary_values() >> inside the loop >> alter the system_matrix that is meant to be constant (independent of iterate >> u)? > > It doesn't change it any further than it was changed the first time around. > But it doesn't do the appropriate modifications: you need the original matrix > for this to work. > > > >> If the answer is no, then the above code will be fine, I guess. >> If the answer is yes, I guess I'll need to assemble system_matrix inside the >> loop repeatedly >> even though it is independent of the iterate u. > > Right. Or do what step-26 does -- gosh darn, there seems to be a tutorial > program for everything ;-) (It's Friday afternoon and I'm already having a > drink -- the joster in me is shining through...) > > Cheers > W. > -- > ------------------------------------------------------------------------ > Wolfgang Bangerth email: bange...@colostate.edu > www: http://www.math.colostate.edu/~bangerth/ > > -- > 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. > To view this discussion on the web visit > https://groups.google.com/d/msgid/dealii/87651284-e7f5-1476-8c5a-5da7cd05c2c3%40colostate.edu. -- 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. To view this discussion on the web visit https://groups.google.com/d/msgid/dealii/A4DEB75D-12FB-472B-B0B6-C4CE9FFCDCC1%40gmail.com.
