Posting reply to list. On Tue, Aug 7, 2018 at 9:40 AM Bailey Curzadd <bcurza...@gmail.com> wrote:
> That's correct. > > Paul T. Bauman <ptbau...@gmail.com> schrieb am Di., 7. Aug. 2018, 15:32: > >> To clarify, do you mean unstructured here in the sense that the two >> boundaries that are to be periodic are not simply a translation of one >> another? E.g. nodes do not match up? >> >> On Tue, Aug 7, 2018 at 9:08 AM Bailey Curzadd <bcurza...@gmail.com> >> wrote: >> >>> Hi there, >>> >>> I'm using libMesh to calculate the homogenized properties of >>> microstructures with cuboid unit cells. To do this, the boundaries of the >>> unit cell require periodic boundary conditions. As far as I can tell, >>> though, the PeriodicBoundary class only works with structured meshes, >>> which >>> isn't really a feasible option for me. Is this really the case, or have I >>> just missed something in my implementation? >>> >>> Currently, I am manually mapping each constrained node on the "far" >>> boundary to an element/side pair on the "near" boundary using >>> PointLocatorBase and Elem::side_ptr()->contains_point(). Then, I use the >>> penalty method to apply a constraint equation with coefficients found >>> using >>> FE<2,LAGRANGE>::shape(). >>> >>> The issue I have at the moment most likely concerns preallocation of the >>> system matrix. Calls to matrix->add_matrix() are taking a very long time, >>> since the DofMap would obviously not expect a node on one side of the >>> mesh >>> to be coupled with the nodes on the opposite side. Is there a convenient >>> way to make libMesh preallocate extra space beforehand, or does this need >>> to be done manually? I'm using PETSc, but I'd like the code to stay >>> solver-independent if possible. >>> >>> I've considered switching to the Lagrange multiplier method using 2 >>> additional field variables as was suggested for a question I posted >>> earlier >>> for a different project. However, this would add 2 DOFs to each node, and >>> I'm not even sure this would circumvent the preallocation problem I have >>> for the penalty method. Any suggestions concerning the best way to use >>> libMesh for this problem would be appreciated. >>> >>> - Bailey C >>> >>> ------------------------------------------------------------------------------ >>> Check out the vibrant tech community on one of the world's most >>> engaging tech sites, Slashdot.org! http://sdm.link/slashdot >>> _______________________________________________ >>> Libmesh-users mailing list >>> Libmesh-users@lists.sourceforge.net >>> https://lists.sourceforge.net/lists/listinfo/libmesh-users >>> >> ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Libmesh-users mailing list Libmesh-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libmesh-users
