CP2K is a quantum chemistry and solid-state physics software package that can perform atomistic simulations of solid-state, liquid, molecular, periodic, material, crystal, and biological systems.

Versions¶

The latest version installed is CP2K 8.2. You can load the module compiled with GCC using:

module load StdEnv/2020  gcc/9.3.0  openmpi/4.0.3 cp2k/8.2

Intel-Compiled Version Stability

While an Intel-compiled version is available, it appears less stable and has been observed to crash for unknown reasons. The GCC-compiled module is generally recommended.

module load StdEnv/2020  intel/2020.1.217  openmpi/4.0.3 cp2k/8.2

Example job¶

Here we will use the static calculation example from the CP2K website.

First, log into one of our clusters and download the needed files with the following commands:

wget https://www.cp2k.org/_media/static_calculation.tgz
tar xvfz static_calculation.tgz
cd static_calculation/sample_output_no_smearing

Then, in that directory, create the following job submission script, with the account name changed to the one you are using.

mpi_job.sh

#!/bin/bash
#SBATCH --account=def-someuser
#SBATCH --ntasks=4               # number of MPI processes
#SBATCH --mem-per-cpu=4G      # memory; default unit is megabytes
#SBATCH --time=0-00:15           # time (DD-HH:MM)

module load StdEnv/2020  gcc/9.3.0  openmpi/4.0.3 cp2k/8.2
srun cp2k.popt -o Si_bulk8.out Si_bulk8.inp

To submit this job, execute:

sbatch mpi_job.sh

To see if the job completed, run the command:

sq

If your job is no longer listed, that means it has completed.

The output of CP2K will be located in the file Si_bulk8.out. There will also be an output file named slurm-*.out which should be empty if the calculation completed without error.

Threaded/MPI jobs¶

The installation of CP2K version 8.2 and later includes both the MPI executable cp2k.popt and the OpenMP/MPI executable cp2k.psmp, which may give better performance for some calculations. Our test shows a 10% performance increase for QS/H2O-512.inp benchmark when using 2 threads per MPI process, compared to running MPI-only executable cp2k.popt (both runs used the same number of CPU cores in total).

Considerations for Threaded/MPI Jobs

The example OpenMP/MPI job submission file below is configured for the Beluga cluster. If you are using other clusters, you will need to adjust the number of tasks to match the available cores on that cluster's nodes. It is crucial to note that performance with threads can be highly problem-dependent. Running the cp2k.psmp executable might even be slower in some cases. Always benchmark your code to determine the optimal configuration for your specific scenario.

```bash title="openmp_mpi_job.sh"

!/bin/bash¶

SBATCH --account=def-someuser¶

SBATCH --nodes=2¶

SBATCH --ntasks=40 # number of MPI processes¶

SBATCH --cpus-per-task=2¶

SBATCH --mem-per-cpu=3G # memory; default unit is megabytes¶

SBATCH --time=0-00:59 # time (DD-HH:MM)¶

module load StdEnv/2020 gcc/9.3.0 openmpi/4.0.3 cp2k/8.2

export OMP_NUM_THREADS=$SLURM_CPUS_PER_TASK srun --cpus-per-task=$OMP_NUM_THREADS cp2k.psmp -o H2O-512.out H2O-512.inp