Dear Wolfgang, Thank you for the hints. The second approach seems easy to start with.
One follow-up question: The mesh (which is initially periodic at the boundaries) is refined adaptively during the simulation and it cannot be guaranteed if both the left and the right boundary faces would be refined at the same time. Will make_periodicity_constraints() work in that case? If yes, how would the periodic constraints look like for the child cell dofs? In case it matters, I currently have a dealii::Triangulation and also wish to update to p:d:T in future. Going through step-45 and the docu of collect_periodic_faces(), it was not clear to me what would happen for the case I described above. Thanks and best regards, Paras On Thu, Apr 14, 2022 at 10:24 PM Wolfgang Bangerth <bange...@colostate.edu> wrote: > > Paras, > I don't think there is a way that's already implemented, but if you look > at > the function that implements the periodic boundary conditions, you should > be > able to clone it in your project and add the negative sign where necessary. > > Alternatively, you can let the existing function create an AffineMatrix > object, and then iterate over it to create a second such object that has > the > opposite sign. > > Best > W. > > > On 4/14/22 11:28, Paras Kumar wrote: > > *** Caution: EXTERNAL Sender *** > > > > Dear dealii Community, > > > > I am working on a solid mechanics related problem involving > anti-periodic > > constraints, i.e. > > > > u_leftFace = - u_RightFace, > > > > where u is the unknown field (a component of the dim-dimensional > displacement > > field). > > > > One possible solution, I am aware of, involves marking the periodic > faces by > > means of boundary-ids, traversing through the dofs for each periodic > face-pair > > in order to determine the periodic dof pair and then manually add the > entry in > > the constraint matrix. This approach also worked for cases involving > periodic > > constraints with offsets. > > > > I would like to know if there exists a simpler way of achieving the > > aforementioned goal by a simpler approach, probably by passing some > > appropriate parameters to the make_periodicity_constraints() function, > since > > we just have a sign change here. > > > > Thanks and best regards, > > Paras > > > > -- > > The deal.II project is located at http://www.dealii.org/ > > < > https://nam10.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.dealii.org%2F&data=04%7C01%7CWolfgang.Bangerth%40colostate.edu%7C8f9fc858ff034f0e15ef08da1e3c3094%7Cafb58802ff7a4bb1ab21367ff2ecfc8b%7C0%7C0%7C637855542161551806%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=D5%2B%2Fl2JSIEzLD8yAQ0g8S4npa7iZJBXOm0RNWrcMpW0%3D&reserved=0 > > > > For mailing list/forum options, see > > https://groups.google.com/d/forum/dealii?hl=en > > < > https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgroups.google.com%2Fd%2Fforum%2Fdealii%3Fhl%3Den&data=04%7C01%7CWolfgang.Bangerth%40colostate.edu%7C8f9fc858ff034f0e15ef08da1e3c3094%7Cafb58802ff7a4bb1ab21367ff2ecfc8b%7C0%7C0%7C637855542161551806%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=sBAFfhzgWJFRRvlWTXcZSvJrGGwXyIgarIHw04NnhB4%3D&reserved=0 > > > > --- > > 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 > > <mailto:dealii+unsubscr...@googlegroups.com>. > > To view this discussion on the web visit > > > https://groups.google.com/d/msgid/dealii/b2783034-32fe-43d0-80fa-5ace7204f6c0n%40googlegroups.com > > < > https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgroups.google.com%2Fd%2Fmsgid%2Fdealii%2Fb2783034-32fe-43d0-80fa-5ace7204f6c0n%2540googlegroups.com%3Futm_medium%3Demail%26utm_source%3Dfooter&data=04%7C01%7CWolfgang.Bangerth%40colostate.edu%7C8f9fc858ff034f0e15ef08da1e3c3094%7Cafb58802ff7a4bb1ab21367ff2ecfc8b%7C0%7C0%7C637855542161551806%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=DyeuUwE%2BH%2FQKzLAzF9lQhGU%2By4gvef3I%2FYUg%2FklzVJg%3D&reserved=0 > >. > > > -- > ------------------------------------------------------------------------ > 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 a topic in the > Google Groups "deal.II User Group" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/dealii/Y82j-T65T00/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > dealii+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/dealii/72a3bb09-99bc-c9ea-1229-a4692c50b70e%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. 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