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VASP
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 Roihu. That said, using VASP efficiently requires experience. It is advised that new VASP users start out with a supervisor or an experienced colleague.
License
Commercial, more info from VASP Portal.
VASP executables
There are two ways to get access to VASP executables. You can build your own executables, or you can get a personal license key and use CSC's pre-built executables.
Build your own VASP executables
This is simple and documented in GitHub. This is also the way if you want to develop VASP, build modified versions of VASP, or have acquired the license from Materials Desing Inc.
If you run into any issues building VASP, please send feedback to CSC's ServiceDesk.
Use CSC's pre-built executables
You can see the available VASP versions with command
The use of the pre-built executables requires that each user gets a personal
license key, and updates it when necessary. The license key is stored
in the home directory in the file ~/.vasp/vasp_license.
The license file is downloaded from the VASP portal with commands
The request_license_key.sh script will ask user's VASP Portal username and password.
VASP batch jobs
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
Performance optimisation
VASP performance depends crucially on the parameters in the INCAR file and that the correct version (std/gam/ncl) of the executable is used. The INCAR parameters control how the different k-points, bands and FFT coefficients are distributed among the MPI tasks, among many other things. Initial settings for the parameters can be found from the VASP documentation, but in most cases finding optimal parameters requires experience and experimentation, and depend on the studied system and the underlying computational platform.
VASP tutorials in JupyterLab
VASP tutorials can also be
followed using JupyterLab from the
Roihu web interface. Open the Jupyter app,
and from Settings -> Python, select Custom module and type in
py4vasp. Launch vasp example runs from a separate login shell terminal
using srun command, for example,
instead of mpirun ... commands as in the Vasp tutorial.