[SOLVED] Can't run simple mpi program

Can't run simple mpi program

I recently installed Intel's Cluster Studio, and was testing IMPI. When I try running a simple hello world program using mpirun, the process takes forever, and I have to end it myself. I used the following code:

#include <mpi.h>
#include <iostream>

#include <stdlib.h>

int main(int argc, char *argv[]) {
  MPI::Init(argc, argv);

  int rank = MPI::COMM_WORLD.Get_rank();
  int size = MPI::COMM_WORLD.Get_size();

  std::cout << "Returned: " << system("sleep 2") << " ";
  std::cout << "Hello World! I am " << rank << " of " << size <<
          std::endl;

  MPI::Finalize();
  return (0);
}

I compiled it with mpiicpc main.cpp -o main. This is the output when I added -show option:

icpc main.cpp -o main -I/opt/intel/impi/4.1.1.036/intel64/include -L/opt/intel/impi/4.1.1.036/intel64/lib -Xlinker --enable-new-dtags -Xlinker -rpath -Xlinker /opt/intel/impi/4.1.1.036/intel64/lib -Xlinker -rpath -Xlinker /opt/intel/mpi-rt/4.1 -lmpigc4 -lmpigf -lmpi -lmpigi -ldl -lrt -lpthread

I ran the executable with mpirun -np 4 main.

Additional info:

$which mpirun 
/opt/intel/impi/4.1.1.036/intel64/bin/mpirun

$mpiicpc --version
icpc (ICC) 14.0.0 20130728

UPDATE: I also tried compiling it using g++ instead of icpc. No luck. My guess is there is a problem with the MPI runtime, but I can't find it. Debugging didn't work. I think the program is not initializing in the first place.

Solution

If someone is still interested, I found out what was wrong. According to this link, Unlike some other MPI implementations, Intel MPI Library uses a Multi-Purpose Daemon (MPD) job startup mechanism. To run programs compiled with mpicc (or related) commands, you must first set up MPD daemons. So, I followed the steps explained in the link, executed the mpdbootcommand, and voilà, It works finally.