VASP
VASP is an ab initio DFT program for computing electronic structures of up to few hundreds of atoms.
This page briefly describes how to use VASP on mahti.csc.fi. Usage on puhti.csc.fi is very similar. That said, VASP is a program the usage of which requires some experience. It is advised that new VASP users start out with a supervisor or an experienced colleague.
Available
See available VASP versions in with command
module avail vasp
License
The usage of VASP requires a license, which must be acquired directly from the developers of the software.
After acquiring the license, please send email to CSC Service Desk, including the email address you have registered for the VASP license and your username at CSC.
Usage
Precompiled VASP executables and pseudopotentials are available through the module environment. Use the command
module show vasp
to see more detailed information.
An example batch job script for a small test
#!/bin/bash
#SBATCH --time=00:15:00
#SBATCH --partition=test
#SBATCH --ntasks=4
#SBATCH --mem-per-cpu=1GB
#SBATCH --account=<project>
module load vasp
srun vasp_std
For more options and details, see how to create batch job scripts for Puhti and Mahti.
VASP tutorials in JupyterLab
VASP tutorials can also be
followed using JupyterLab from the
Mahti web interface. Open the Jupyter app,
and from Settings -> Python, select Custom module and type in
py4vasp. When submitting jobs from the JupyterLab terminal window to
compute nodes, first load module vasp, and then use a command similar to
srun -p test -A <project> -t 5 -n 2 vasp_std
instead of the mpirun ... command shown in the tutorial.
Performance optimization
First, the performance of VASP depends crucially on the parameters in the INCAR file that control how the different k-points, bands and FFT coefficients are distributed among the MPI tasks, and that the correct version (std/gam/ncl) of the executable is used.
Second, the provided prebuilt executables are built as "vanilla" as
possible and provide a reasonable baseline. The performance
optimization for large experiments should be done on a per case basis.
The commands that created the prebuilt executables are in
$VASPDIR/README.sh, and can be used as a starting point
for building more optimized and/or otherwise modified executables.