Hi Javiear, I would guess that the solver cound not obtain the desired tolerance with the maximal number of iterations maxit=1000 number of iterations. In principal, you can increase the number of maxit as already suggested or you can make your system "nicer" by considering preconditioning. http://en.wikipedia.org/wiki/Preconditioner
Best, Martin On 1/12/12, Javier Muñoz <[email protected]> wrote: > Hi > > I am practicing the tutorials examples of Deal.ii. In step-9, which > deals with the advection equation and shows the use of refinement > meshing, I am trying to use a different mesh, generated with Gmsh (I > attach the file). > > if (cycle == 0) > { > // GridGenerator::hyper_cube (triangulation, -1, 1); > // triangulation.refine_global (4); > > GridIn<dim> grid_in; > grid_in.attach_triangulation (triangulation); > std::ifstream input_file ("square.msh"); > grid_in.read_msh (input_file); > } > else > { > refine_grid (); > }; > > > The domain is the same and no other modifications were made. After 3 > cycles the program gives me an error about convergence: > > > Cycle 0: > Number of active cells: 416 > Number of degrees of freedom: 453 > Cycle 1: > Number of active cells: 1043 > Number of degrees of freedom: 1204 > Cycle 2: > Number of active cells: 2657 > Number of degrees of freedom: 3077 > > > ---------------------------------------------------- > Exception on processing: > Iterative method reported convergence failure in step 1000 with residual > 3.12503e-07 > Aborting! > ---------------------------------------------------- > > > I have no idea why I'm receiving this error. Can you give me any > suggestions? > > Best Regards > Javier Muñoz > > > -- Martin Stoll Postdoctoral Research Fellow Computational Methods in Systems and Control Theory Max Planck Institute for Dynamics of Complex Technical Systems Sandtorstr. 1, D-39106 Magdeburg,Germany Email: [email protected] <[email protected]> URL: http://www.mpi-magdeburg.mpg.de/mpcsc/stollm/ Tel :+49 391 6110 805 _______________________________________________ dealii mailing list http://poisson.dealii.org/mailman/listinfo/dealii
