Hi Tim, You can specify variables that are defined only on X2 by specifying the appropriate subdomain id(s) when you add the variable to the system. See add_variable in system.h
David On 09/09/2010 09:27 AM, Tim Kroeger wrote: > Dear all, > > Let X be a computational domain, covered by a Mesh on which an > EquationSystems object is based on. Let X2 be a subset of X, given by > the union of selected grid elements (which are, say, marked by certain > values of subdomain_id). > > Assume I want (at some point in my application) to solve a system only > on X2 (say, using Dirichlet boundary conditions on all boundaries of > X2 that are not boundaries of X). > > I can easily achieve this by assembling Dirichlet conditions > everywhere ouside X2 and then solving as usual. However, then I > cannot benefit from the performance gain that I should theoretically > have if X2 contains much less elements than X. This is in particular > true if I am using a direct solver (such as SuperLU_DIST, wrapped via > PETSc). > > What is the easiest way to do this more efficiently, that is, > > (1) let SuperLU_DIST only see the necessary part of the matrix, > > (2) if possible, guarantee a sensible load-balancing, and > > (3) not run into problems due to dofs that appear free if viewed from > inside X2 but are actually constrained in X > > ? > > Thank you in advance for your ideas. > > Best Regards, > > Tim > ------------------------------------------------------------------------------ This SF.net Dev2Dev email is sponsored by: Show off your parallel programming skills. Enter the Intel(R) Threading Challenge 2010. http://p.sf.net/sfu/intel-thread-sfd _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
