On Wed, Nov 10, 2010 at 04:40:47PM +0000, Garth N. Wells wrote: > > > On 10/11/10 16:10, Anders Logg wrote: > >On Wed, Nov 10, 2010 at 03:58:13PM +0000, Garth N. Wells wrote: > >> > >> > >>On 10/11/10 15:47, Anders Logg wrote: > >>>On Wed, Nov 10, 2010 at 02:47:30PM +0000, Garth N. Wells wrote: > >>>>Nice to see multi-thread assembly being added. We should look at > >>>>adding support for the multi-threaded version of SuperLU. What other > >>>>multi-thread solvers are out there? > >>> > >>>Yes, that would be good, but I don't know which solvers are available. > >>> > >>>>I haven't looked at the code in great detail, but are element > >>>>tensors being added to the global tensor is a thread-safe fashion? > >>>>Both PETSc and Trilinos are not thread-safe. > >>> > >>>Yes, they should. That's the main point. It's a very simple algorithm > >>>which just partitions the matrix row by row and makes each process > >>>responsible for a chunk of rows. > >> > >>Would it be better to partition the mesh (using Metis) and then > >>renumber dofs? That way the 'all_in_range' case would be maximised > >>and the 'some_in_range' would be minimised. If the rows are > >>distributed, mixed elements will be a mess because the global rows > >>are far apart (using the FFC-generated dof map). > > > >Renumbering is definitely important for getting good speedup. This > >hasn't been added yet but was implemented in the prototype version > >(which was stand-alone from DOLFIN). > > > > What about partitioning of the mesh?
I'm not sure that would help. If each process has access to the whole mesh, which is either one big connected mesh or a connected piece of the mesh when running in parallel with MPI, then renumbering on that piece should be enough. Or am I missing something? -- Anders _______________________________________________ Mailing list: https://launchpad.net/~dolfin Post to : [email protected] Unsubscribe : https://launchpad.net/~dolfin More help : https://help.launchpad.net/ListHelp
