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?
Michael.
On 06/13/2018 12:28 PM, John Peterson wrote:
On Wed, Jun 13, 2018 at 10:14 AM, Michael Povolotskyi
<mpovo...@purdue.edu <mailto:mpovo...@purdue.edu>> wrote:
Thank you John,
I do have some MPI code before LibMeshInit in my real application.
Also, If I do not call MPI_Finalize at the very end I'm getting
warning messages from MPI.
Thank you for you explanation with .pvtu, I have changed my code
to libMesh::VTKIO out(mesh); out.write("mesh1.pvtu"); and this
worked.
Do you have any suggestions for the Problem #2 that I reported?
It seems to me that the problem is that the communicator of the
Mesh object is smaller than the communicator of the VTK. This
causes a problem for me.
Hmm, I don't think we have considered this use case in the past, the
vtkMPIController is initialized in libmesh.C, and it must be assuming
MPI_COMM_WORLD...
_vtk_mpi_controller = vtkMPIController::New();
_vtk_mpi_controller->Initialize(&argc, const_cast<char ***>(&argv),
/*initialized_externally=*/1);
_vtk_mpi_controller->SetGlobalController(_vtk_mpi_controller);
In order for the parallel VTK writer to work, the Mesh probably
therefore also needs to be using MPI_COMM_WORLD.
--
John
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