Hello again, We found the issue thanks to Peter Munch. When setting up our problem, we can use the function make_consistent_in_parallel() with our constraints after the line constraints.close(). If the Deal.II team think it's appropriate, I could submit a small PR next week to add this line and a quick explanation to the step-75 tutorial so others don't run into the same issue in the future.
Thank you, Mikael Le vendredi 25 avril 2025 à 08:29:32 UTC-4, Mikael Vaillant a écrit : > Hi everyone, > > We are currently working on a prototype to solve a Poisson non-linear > problem using hp-refinement. The prototype was first tested using a linear > equation. The problem is that we obtain multiple non-linear newton > iterations to solve our linear equation after a couple of adaptation steps. > This issue appears only when running the code in parallel. We don't have > the problem when running the code using only p refinement, only h > refinement or with certain geometries. We based our prototype on the > step-75 but have not been able to identify if the issue is contained within > our code. We found the issue appears when two cells sharing a vertex and > that are not part of the same subdomain have an FE degree difference of > more than two or when the first one has a p-refinement and an h-refinement > superior than a cell sharing its vertex. > > Here are some pictures of the outputted results in Paraview. A threshold > is applied to look at some cells where the residual is abnormally > high.[image: > image.png][image: image_720.png][image: image.png] > > I was wondering if functions such as limit_p_level_difference() allow for > cases where a neighbouring cell sharing a vertex has a polynomial order > difference of more than 2? Im also wondering why this problem is only > appearing in parallel. I'm looking for any insight that could help me > understand what could cause this issue. > > Thank you, > > Mikael > -- 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 [email protected]. To view this discussion visit https://groups.google.com/d/msgid/dealii/0125fa2f-bf59-4be3-a0c7-0ff5369dbf41n%40googlegroups.com.
