1. Log in to your university's designated login server via SSH:
   

   # Uni Wien
   ssh <username>@vsc.univie.ac.at
   
   # TU Wien
   ssh <username>@vsc.tuwien.ac.at
   
   # Boku Wien
   ssh <username>@vsc.boku.ac.at

2. Transfer your programs and data/input files to your home directory.

       scp <filename> <username>@vsc.univie.ac.at:~/
       

3. (Re-)Compile your application. Please use the latest “Intel” MPI-Environment as described in MPI Environment.

Define name and number of slots:

#$ -N <job_name>
#$ -pe mpich <slots>
#$ -V

where “<job_name>” is a freely chosen descriptive name and “<slots>” is the number of processor cores that you want to use for the calculation. To ensure exclusive reservation of the compute nodes for your job, the value for “<slots>” has to be a multiple of 8. “-V” declares that all environment variables in the qsub command's environment are to be exported to the batch job.

The job can be started in several ways,

1. as single core job on one core (no MPI) task

   ./<executable>

2. as parallel single core job (no MPI) on parallel cores (see also Sequential code)
3. as parallel job (using MPI)

   mpirun  -m $TMPDIR/machines -np $NSLOTS <executable>

Substitute the path to your MPI-enabled application for <executable> and you are ready to run!
To receive E-Mail notifications concerning job events (b .. beginning, e .. end, a .. abort or reschedule, s .. suspend), use these lines in your job script:

#$ -M <email address to notify of job events>
#$ -m beas  # all job events sent via email

It is often advisable to also specify the job's runtime as

#$ -l h_rt=hh:mm:ss

in particular when you know that your job will run only for several hours or even minutes. That way one can “backfill” the queue, thus avoiding very long waiting times, which may be due to a highly parallel job waiting for free resources.
Here is an example job-script, requesting 32 processor cores, which will run for a maximum of 3 hours and sends emails at the beginning and at the end of the job:

#$ -N hitchhiker
#$ -pe mpich 32
#$ -V
#$ -M my.name@example.at
#$ -m be
#$ -l h_rt=03:00:00

mpirun  -m $TMPDIR/machines -np $NSLOTS ./myjob

In order to reduce the time in the queue, see the section on maximum runtime specification.

1. qsub <job_file>

   where “<job_file>” is the name of the file you just created.

2. Check if and where your job has been scheduled:
   

   qstat

3. Inspect the job output. Assuming your job was assigned the id “42” and your job's name was “hitchhiker”, you should be able to find the following files in the directory you started it from:
   

   $ ls -l
   hitchhiker.o42
   hitchhiker.e42
   hitchhiker.po42
   hitchhiker.pe42

   In this example hitchhiker.o42 contains the output of your job. hitchhiker.e42 contains possible error messages. In hitchhiker.po42 and hitchhiker.pe42 you might find additional information related to the parallel computing environment.