ORCA

1 Overview | 2 Using | 2.1 Multicore:

Overview

MPI CEC: Max Planck Institute for Chemical Energy Conversion
- An ab initio, DFT and semiempirical SCF-MO package.
- Please read the “End User License Agreement (EULA) for the ORCA software” before using the software:

Using

Use the module name orca to discover versions available and to load the application.

Multicore:

The orca application can run across multiple cores and nodes using OpenMPI.

If using across multiple tasks/nodes then the nprocs value in the .inp file:

%pal nprocs 8
  end

must match up to the number of requests nodes multiplied requested tasks per node:

#SBATCH --nodes=2
#SBATCH --ntasks-per-node=4

Note 01: You need to provide the full path to the orca command. To find what this is, module load your version of orca and then use the which command. For example, on Beartooth:

[@blog1 orca]$ module load orca/5.0.3
[@blog1 orca]$ which orca
/apps/u/opt/linux/orca/5.0.3/bin/orca

Note 02: Typically for an MPI related task you would prefix your call with srun. You do NOT have to do this with orca., as it performs an mpirun ... behind the scenes.