Psi is an ab initio computational chemistry package. Utilizing Psi, one can perform a calculation on a molecular system with various kinds of methods such as Hartree-Fock, Post-Hartree–Fock electron correlation methods, and Density functional theory. The program can compute energies, optimize molecular geometries, and compute vibrational frequencies. The major part of the program is written in C++, while Python API is also available, which allows users to perform complex computations or automate tasks easily.
Psi4 is the latest release of the program package. PSI4 provides a wide variety of quantum chemical methods using state-of-the-art numerical methods and algorithms. Several parts of the code feature shared-memory parallelization to run efficiently on multi-core machines. An advanced parser written in Python allows the user input to have a very simple style for routine computations, but it can also automate very complex tasks with ease.
Sample Script:
#!/bin/bash
#SBATCH --account=chemistry
#SBATCH --error=job.%J.err
#SBATCH --output=job.%J.out
#SBATCH --job-name=test
#SBATCH --nodes=1
#SBATCH --ntasks-per-node=1 ###Number of tasks per node (aka MPI processes)
#SBATCH --cpus-per-task=6 ###Number of cpus per task (aka OpenMP threads)
#SBATCH --time=14-00:00:00
module load compilers/intel/parallel_studio_xe_2019.3.062
module load apps/psi4/1.3.2
export INPUTFILE=methanedimer.in
export OUTPUTFILE=methanedimer.out
export PSI_SCRATCH=/scratch/username/psi4_file
export OMP_NUM_THREADS=4
#srun psi4 -i ${INPUTFILE} -o ${OUTPUTFILE}
mpiexec.hydra -n 6 psi4 -i ${INPUTFILE} -o ${OUTPUTFILE}
#mpirun -n 6 psi4 methanedimer.in > methanedimer_new.out