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
