[dogukanteber]

I have been trying to parallelize the decomposePar utility in OpenFOAM, for more information https://www.cfd-online.com/Forums/openfoam-programming-development/243964-parallelizing-decomposepar-utility.html) Therefore, I need to call MPI routines in my new utility. I learned that OpenFOAM has Pstream wrapper for MPI routines. However, my program throws an error when I do not call decomposePar before I run the program. For instance, below is a basic hello world program:

 #include "fvCFD.H"
 
 int main(int argc, char* argv[]) {
   #include "setRootCase.H"

   #include "createTime.H"
   // cannot run in parallel without creating processor0 directory
   Pout << "Hello from process " << Pstream::myProcNo() << endl;

   return 0;
 }

Here are the commands that I execute in order (assume I have compiled my source file):

blockMesh
mpirun -np 4 <program-name> -parallel

And, here is the error message:

Pstream initialized with:
   floatTransfer   : 0
   nProcsSimpleSum  : 0
   commsType     : nonBlocking
   polling iterations : 0
 trapFpe: Floating point exception trapping enabled (FOAM_SIGFPE).
 fileModificationChecking :  Monitoring run-time modified files using timeStampMaster  (fileModificationSkew 5, maxFileModificationPolls 20)
 allowSystemOperations : Allowing user-supplied system call operations


 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 [0] 
 [0] 
 [0] --> FOAM FATAL ERROR: (openfoam-2106)
 [0] parallelDecompose: cannot open case directory "/home/dogukan/Documents/hydrology/tutorials/permaFoam/demoCase/processor0"
 [0] 
 [0] 
 FOAM parallel run exiting
 [0] 
 --------------------------------------------------------------------------
 MPI_ABORT was invoked on rank 0 in communicator MPI_COMM_WORLD
 with errorcode 1.


 NOTE: invoking MPI_ABORT causes Open MPI to kill all MPI processes.
 You may or may not see output from other processes, depending on exactly when Open MPI kills them.

When I call below functions, everything works as expected:

blockMesh
decomposePar
mpirun -np 4 <program-name> -parallel

I want to run my program after I call blockMesh so that I can parallelize the decomposePar utility. Is it possible to use Pstream methods without calling the decomposePar utility?




OpenFOAM version: v2106


Thanks in advance