• OpenMP is a shared-memory parallel programming model. For more information on OpenMP, see http://www.openmp.org.

• pgf77 and pgf90 Fortran compilers support the OpenMP Fortran Application Program Interface. Use -mp option to instruct the compiler to interpret user-inserted OpenMP shared-memory parallel programming directives and generate an executable file which will utilize multiple processors in a shared-memory parallel system. Here is a typical compilation command:
  
  $ pgf90 -mp -o myprog.e myprog.f
  
  Without -mp, the compiler will ignore user-inserted shared-memory parallel programming directives and pragmas.

• The next is a typical shell script, saved in file "omp.sh", for submitting the OpenMP job through SGE:
  
  --------------------------------------------
  #!/bin/bash
  #$ -V
  #$ -cwd
  #$ -pe threaded 2
  #
  export OMP_NUM_THREADS=$NSLOTS
  
  time myprog.e
  --------------------------------------------
  

• The line "#$ -pe threaded 2" specifies the SGE Parallel Environment 'threaded' (which is the proper one to use for OpenMP jobs) with 2 slots, i.e. $NSLOTS=2.
  The maximum number of slots is limited to 8 in one node.

• Submit the job through SGE:
  
  $qsub omp.sh

• Check the status of the job:
  
  $qstat -f
  

Back to Aster Q/A