Dear Igor, Unfortunately, the parrallelization of Getfem is still incomplete. You are right, th brick mdbrick_QU_term is not parallelized. In fact, the modification to parallelize it is not difficult. You have to replace the last argument of asm_qu_term, which is boundary, by the term mf_u.linked_mesh().get_mpi_sub_region(boundary) in the definition of the brick (getfem_modeling.h). The effect is that the assembly will be done in a distributed way with respect to a partition of the mesh done with metis.
In fact, all model brick have to be modified in that way to be used in a parallel version. I commit this change in the gna repository. Best regards, Yves. On Friday 03 April 2009 11:29, Igor Peterlik wrote: > Dear GetFEM team, > > I would like to ask about a bit strange behavior of the QUterm brick > being used with GETFEM_PARA_LEVEL=2. > First, I noticed that my application composed of the Helmholtz, > Dirichlet (twice) and QUterm bricks gives > different results in sequential and parallel version (and moreover the > result in parallel version depends on the number of > the processors). I found out that the QUterm brick modifies the entire > system matrix on each process. Maybe I had missed > something but it seemed to me that this was not correct behavior > (maybe QUterm is not compatible with paralel mode...). > As a workaround, I added a condition to the gmm:add as shown below: > > if (getfem::MPI_IS_MASTER()) > gmm::add(get_K(), gmm::sub_matrix(MS.tangent_matrix(), SUBI)); > > in the mdbrick_QU_term::do_compute_tangent_matrix(). > so the system matrix is modified only once. It seems this helped, > since the solution is now invariant wrt. the number > of CPUs. Nevertheless, this is not the real solution I guess. > > BTW is there some (at least) small documentation concerning the > paralelization (which parts are parallelized and how)? > > Regards > > Igor > > _______________________________________________ > Getfem-users mailing list > [email protected] > https://mail.gna.org/listinfo/getfem-users -- Yves Renard ([email protected]) tel : (33) 04.72.43.87.08 Pole de Mathematiques, INSA-Lyon fax : (33) 04.72.43.85.29 20, rue Albert Einstein 69621 Villeurbanne Cedex, FRANCE http://math.univ-lyon1.fr/~renard --------- _______________________________________________ Getfem-users mailing list [email protected] https://mail.gna.org/listinfo/getfem-users
