VASP

Overview

VASP (Vienna Ab initio Simulation Package) is a plane-wave electronic structure code. Among its capabilities are density functional theory (DFT) calculations and ab initio molecular dynamics simulations.

Note

VASP is licensed software. OLCF cannot provide access to VASP unless you or your organization hold a valid license. To gain access to the centrally installed module, contact User Assistance through the support portal with proof of your license (for example, a copy of your VASP license agreement or confirmation from the VASP team), and you will be added to the vasp Unix group that controls access to the software and its documentation.

Package Details

Application or Library

Version

Short Description

VASP

6.6.1

Electronic structure calculations and ab initio molecular dynamics

ROCm

6.4.2

AMD GPU runtime.

Cray MPICH

9.0.1

MPI implementation for parallel execution

Usage

To use VASP, load the required modules:

module load vasp/6.6.0-gpu

If the module is not visible with module avail vasp, you have not yet been added to the vasp Unix group. See the note above for how to request access.

Beginner’s Guide

For new users of VASP, an illustration of the workflow for a plane-wave DFT calculation is provided below. Let us use the silicon crystal primitive cell as an example.

0. Prepare a working directory.

Before running a calculation, we need a working directory with the necessary input files and pseudopotentials. Your project directory is a good place to start. For example, if your project directory is /lustre/orion/<project id>, you might create a working directory named vasp-silicon-example in the scratch space like:

mkdir -p /lustre/orion/<project id>/scratch/vasp-silicon-example
cd /lustre/orion/<project id>/scratch/vasp-silicon-example

1. Prepare the input files.

A VASP calculation requires four input files: INCAR, POSCAR, POTCAR, and KPOINTS.

INCAR (calculation parameters and settings):

SYSTEM = Silicon primitive cell     ! a name for the calculation
ISTART = 0                          ! start from scratch, no previous wavefunction
ICHARG = 2                          ! construct initial charge density from atomic charges
ENCUT  = 300                        ! plane-wave cutoff energy in eV
EDIFF  = 1E-6                       ! convergence threshold for self-consistency (eV)
ISMEAR = 0                          ! Gaussian smearing of partial occupancies
SIGMA  = 0.05                       ! smearing width in eV

POSCAR (lattice geometry and atomic positions):

Silicon primitive cell
5.43
0.0 0.5 0.5
0.5 0.0 0.5
0.5 0.5 0.0
Si
2
Direct
0.00 0.00 0.00
0.25 0.25 0.25

KPOINTS (Brillouin zone sampling):

Automatic mesh
0
Gamma
4 4 4
0 0 0

POTCAR (pseudopotentials): see the next step.

2. Prepare the pseudopotentials.

A VASP calculation requires a POTCAR file, which is a concatenation of pseudopotential files for each atomic species in the order they appear in POSCAR. Pseudopotentials distributed with VASP are located in $VASP_POTENTIALS_DIR/<functional>/<element> where <functional> can be LDA or PBE. Each directory contains element directories containing the corresponding POTCAR file. For the silicon example, concatenate the silicon pseudopotential into a file named POTCAR in the working directory:

cat $VASP_POTENTIALS_DIR/PBE/Si/POTCAR > POTCAR

If your system has multiple species, concatenate their POTCAR files in the same order the species appear in POSCAR.

3. Prepare the job submission script.

To submit the calculation to the queue, we need a job submission script, like:

#!/bin/bash
#SBATCH -A <project id>
#SBATCH -J Si2-scf
#SBATCH -N 1
#SBATCH -p batch
#SBATCH -o %x-%j.out
#SBATCH -t 10:00

module load vasp/6.6.0-gpu

srun -N 1 -n 1 -c 1 --gpus-per-task=1 --gpu-bind=closest vasp_std > output.log

Here, we request 1 node, with 1 MPI rank, 1 CPU core, and 1 GPU for 10 minutes. This example calculation only takes about one minute, so the requested time is sufficient. Adjust the resource requests and walltime as needed for larger systems.

4. Submit the job to the queue with sbatch.

Now we are ready to submit the job. Use the sbatch command to submit the job script to the queue:

sbatch <submit script>

Once in the queue, you can check the job status with squeue -u <username>. Once the job starts running, VASP writes its results to several output files, including OUTCAR (a detailed log of the calculation) and vasprun.xml (a structured summary suitable for post-processing), in addition to the output.log file specified in the submit script.

Congratulations! You have successfully run a plane-wave DFT calculation with VASP on Frontier. You can now analyze the output files and explore the results.