I have a C++ program that use MPI for parallelization. I’m trying to write my output as vtkStructuredGrid format in parallel. In fact, I have this function to write the vtk files:
void vtkParallelWriter(int argc, char *argv[],std::vector<double*>colors, std::vector<char*> names, int LX, int LY, int LZ, double x_min, double x_max, double y_min, double y_max, double z_min, double z_max, double local_origin_x, double local_origin_y, double local_origin_z, int nn, int timesnapshot) {
int dims[3] = {LX, LY, LZ};
int global_extent[6] = {x_min, x_max, y_min, y_max, z_min, z_max};
int local_extent[6] = {local_origin_x, local_origin_x+LX-1, local_origin_y, local_origin_y+LY-1, local_origin_z, local_origin_z+LZ-1};
// Create and Initialize vtkMPIController
auto contr = vtkSmartPointer<vtkMPIController>::New();
contr->Initialize(&argc, &argv, 1);
int nranks = contr->GetNumberOfProcesses();
int rank = contr->GetLocalProcessId();
// Create grid points, allocate memory and Insert them
auto points = vtkSmartPointer<vtkPoints>::New();
points->Allocate(dims[0]*dims[1]*dims[2]);
int iterator = 0;
for (int k=0; k<dims[2]; ++k) {
for (int j=0; j<dims[1]; ++j) {
for (int i=0; i<dims[0]; ++i) {
points->InsertPoint(iterator,
local_origin_x+i, local_origin_y+j, local_origin_z+k);
iterator++;
}
}
}
// Create a density field. Note that the number of cells is always less than
// number of grid points by an amount of one so we use dims[i]-1
std::vector<vtkSmartPointer<vtkFloatArray>> vtkColors;
for (int iterator = 0; iterator < colors.size(); iterator++) {
vtkColors[iterator]->SetNumberOfComponents(1);
vtkColors[iterator]->SetNumberOfTuples(dims[0]*dims[1]*dims[2]);
vtkColors[iterator]->SetName(names[iterator]);
int index = 0;
int LXP = nn+LX+nn;
int LYP = nn+LY+nn;
int LZP = nn+LZ+nn;
for (int k=0; k<dims[2]; ++k) {
int K = k + nn;
for (int j=0; j<dims[1]; ++j) {
int J = j + nn;
for (int i=0; i<dims[0]; ++i) {
int I = i + nn;
int IDflattened = I+J*LXP+K*LXP*LYP;
vtkColors[iterator]->SetValue(index, colors[iterator][IDflattened]);
index++;
}
}
}
}
// Create a vtkProgrammableFilter
auto pf = vtkSmartPointer<vtkProgrammableFilter>::New();
// Initialize an instance of Args
Args args;
args.pf = pf;
for(int i=0; i<6; ++i) args.local_extent[i] = local_extent[i];
pf->SetExecuteMethod(execute, &args);
// Create a structured grid and assign point data and cell data to it
auto structuredGrid = vtkSmartPointer<vtkStructuredGrid>::New();
structuredGrid->SetExtent(global_extent);
pf->SetInputData(structuredGrid);
structuredGrid->SetPoints(points);
for (int iterator = 0; iterator < vtkColors.size(); iterator++) {
structuredGrid->GetCellData()->AddArray(vtkColors[iterator]);
}
std::string fileName = std::string("./out/output_") + std::to_string(timesnapshot) + ".pvts";
// Create the parallel writer and call some functions
auto parallel_writer = vtkSmartPointer<vtkXMLPStructuredGridWriter>::New();
parallel_writer->SetInputConnection(pf->GetOutputPort());
parallel_writer->SetController(contr);
parallel_writer->SetFileName(fileName.c_str());
parallel_writer->SetNumberOfPieces(nranks);
parallel_writer->SetStartPiece(rank);
parallel_writer->SetEndPiece(rank);
parallel_writer->SetDataModeToBinary();
parallel_writer->Update();
parallel_writer->Write();
contr->Finalize();
}
Unfortunately, when I run this function, it shows me this error:
==== backtrace (tid: 34166) ====
0 0x0000000000409d63 vtkParallelWriter() ???:0
1 0x000000000040b3f1 main() ???:0
2 0x0000000000022495 __libc_start_main() ???:0
3 0x00000000004083a9 _start() ???:0
Any idea what’s wrong with my parallel vtk writer function? I guess the problem is about vtkMPIController, cause I have a MPI topology in my program but I don’t know how to pass this topology to vtkMPIController.