======= Orca =======

To run Orca, you should register at [[https://orcaforum.cec.mpg.de/]]. For now we are allowed to have Orca installed centrally in the SCC. This may change in the future!

=====  Using ORCA  =====

Load the following modules:
<code>
module load openmpi
module load orca</code>
\\
For a serial job, create a jobscript like:

<code>
#!/bin/bash
#SBATCH -p medium
#SBATCH -n 1
#SBATCH -t 1-00:00:00

INPUTFILE=test.inp

$ORCA_PATH/orca ${INPUTFILE}</code>
\\
This tells the batch system to submit the job to queue medium and require 1 processor for 24 hours.

For parallel jobs, this needs a little trick, since orca can't run on shared filesystems like NFS, CVFS or FHGFS. We need to use /local as a local filesystem for the run:

<code>
#!/bin/bash
#SBATCH -p medium
#SBATCH -J ORCA
#SBATCH -n 20
#SBATCH -N 1
#SBATCH -t 1-00:00:00
#SBATCH --ntasks-per-node=20
#SBATCH --signal=B:12@600
#SBATCH -C local

INPUTFILE=test.inp

work=$PWD

trap 'srun -n ${SLURM_JOB_NUM_NODES} --ntasks-per-node=1 cp -af ${TMP_LOCAL}/* ${work}/; exit 12' 12

cp -af ${INPUTFILE} ${work}/*.gbw ${work}/*.pot ${TMP_LOCAL}/

cd $TMP_LOCAL

$ORCA_PATH/orca ${INPUTFILE} &
wait

srun -n ${SLURM_JOB_NUM_NODES} --ntasks-per-node=1 cp -af ${TMP_LOCAL}/* ${work}/ >/dev/null 2>&1

</code>
\\
This tells the batch system to submit the job to partition medium and require 20 processors on one node for 24 hours. **Please make sure that your input file in this case (-n 20) contains the line '%pal nprocs 20 end' (without quotes)!** '%pal nprocs 20 end' must equal the number of processes you reserve with the '-n' option.

Save the script as myjob.job, for example, and submit with

<code>
sbatch myjob.job</code>