Didn't hit reply-all. On Tue, Aug 7, 2018 at 9:31 AM Paul T. Bauman <[email protected]> wrote:
> 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 <[email protected]> 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 >> [email protected] >> 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 [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
