Re: [Libmesh-users] problems with mesh output: possible solution

[John P. <jwp...@gm...>]

On Wed, Jun 13, 2018 at 11:03 AM, Michael Povolotskyi <mpo...@pu...>
wrote:

> Hello John,
>
> I played with it, and this is what worked for me.
>
> #include <vector>
> #include <sstream>
> using namespace std;
>
> #define private public //to get access to libMesh::LibMeshInit._vtk_mpi_
> controller
>
> #include "libmesh/mesh_generation.h"
> #include "libmesh/mesh.h"
> #include "libmesh/vtk_io.h"
> #include "libmesh/libmesh.h"
> #include "vtkMPIController.h"
> int main(int argc, char ** argv)
> {
>
>   MPI_Init(&argc, &argv);
>
>   {
>     libMesh::LibMeshInit init (argc, argv,MPI_COMM_WORLD);
>     int rank;
>     MPI_Comm_rank(MPI_COMM_WORLD, &rank);
>
>     vtkMPICommunicator* mcomm = vtkMPICommunicator::
> GetWorldCommunicator()->NewInstance ();
>     mcomm->SplitInitialize (mcomm, rank, 0);
>
>     init._vtk_mpi_controller->SetCommunicator (mcomm);
>
>     libMesh::Mesh mesh(libMesh::Parallel::Communicator(MPI_COMM_SELF));
>     libMesh::MeshTools::Generation::build_cube (mesh,
>                                                 10, 10, 5, 0.0, 2.0, 0.0,
> 3.0, 0.0, 4.0,libMesh::HEX8);
>
>
>     if (rank == 0)
>     {
>       libMesh::VTKIO out(mesh);
>       out.write("mesh1.pvtu");
>     }
>   }
>   MPI_Finalize();
>   return 0;
>
>
>
> }
>
> What do you think? Can you provide an access to
> libMesh::LibMeshInit._vtk_mpi_controller?
> Or there is a better solution?
>

I think it would be reasonable to provide a public accessor for
_vtk_mpi_controller, as long as we can still get away with a forward
declaration for vtkMPIController.

Would it be possible to do the same algorithm from within VTKIO::read()? At
that point, we have a Communicator (mesh.comm()) for the Mesh we are
currently writing, so we could probably do the same New/Split/Set series of
steps there, but unfortunately we don't have access to the LibMeshInit at
that point...

-- 
John