OpenMP Software on Odyssey

This page is intended to help you compiling and running you OpenMP applications on the RC cluster. Currently we have both the Intel and GNU compiler suits available. Below are simple example OpenMP codes.

Fortran:

!=====================================================================

! Program: omp_test.f90

!=====================================================================

program omp_test

  implicit none

  integer(4) :: nthreads

  integer(4) :: tid

  integer(4) :: omp_get_num_threads

  integer(4) :: omp_get_thread_num

!$omp parallel private( tid )

  tid = omp_get_thread_num()

  write(6,*)"Thread ID:", tid

  if ( tid == 0 ) then

     nthreads = omp_get_num_threads()

     write(6,*)"Number of threads = ", nthreads

  end if

!$omp end parallel

  stop "End of program."

end program omp_test

C++:

//====================================================================

// Program: omp_test.cpp

//====================================================================

#include <iostream>

#include <string>

#include <sstream>

#include <math.h>

#include <omp.h>

using namespace std;



int main()

{

  int nthreads, tid;

#pragma omp parallel private( tid)

  {

    tid = omp_get_thread_num();

    nthreads = omp_get_num_threads();

    cout << "Thread ID: " << tid << endl;

    if ( tid == 0 ){

      cout << "Number of threads = " << nthreads << endl;

    }

  }

  return 0;

}

Compile the program

Intel, Fortran 90: [username@rclogin02 ~]$ ifort -o omp_test.x omp_test.f90 -openmp

Intel, C++:        [username@rclogin02 ~]$ icpc -o omp_test.x omp_test.cpp -openmp

GNU, Fortran 90:   [username@rclogin02 ~]$ gfortran -o omp_test.x omp_test.f90 -fopenmp

GNU, C++:          [username@rclogin02 ~]$ g++ -o omp_test.x omp_test.cpp -fopenmp

You could use the following LSF batch-job submission script to submit the job to the queue:

#!/bin/sh

#BSUB -n 8

#BSUB -J omp_test

#BSUB -o omp_test.out

#BSUB -e omp_test.err

#BSUB -R "span[ptile=8]"

#BSUB -q short_parallel



export OMP_NUM_THREADS=8

./omp_test.x

Please note that the OpenMP codes will only run on machines with Intel cores. You can ensure this by running only on the following queues:

short_parallel
normal_parallel
long_parallel

References

This page was created by Plamen G. Krastev
Last modified on April 12, 2013 by plamenkrastev@fas.harvard.edu