simpledft 3.0

A simple density functional theory code.

SimpleDFT

SimpleDFT is a simple plane wave density functional theory (DFT) code. It is a Python implementation of the DFT++ pragmas proposed by Thomas Arias et al. Also, it serves as the minimalistic prototype for the eminus code, which was introduced in the master thesis of Wanja Timm Schulze to explain theory and software development compactly. There is also a version written in Julia, called SimpleDFT.jl.

Note: From version 2.0 on, the implementation will slightly deviate from the master thesis to be in line with eminus.

SimpleDFT	Description
Language	Python 3
License	Apache 2.0
Dependencies	Only NumPy
Basis set	Plane waves (PW)
DFT	Restricted Kohn-Sham (RKS)

Installation

The package and all necessary dependencies can be installed using pip

pip install simpledft

Examples

Example calculations, i.e., the H atom, He atom, and H2 molecule can be executed with

python examples.py

Simplifications

This code is about implementing plane wave DFT as simple as possible, while still being general. To classify the shortcomings from a fully-fletched DFT code, the most important simplifications are listed below

• Restricted Kohn-Sham DFT only, no open-shell systems
• LDA only, no functionals using gradients
• All-electron Coulomb potential, no pseudopotentials to only treat valence electrons
• Gamma-point only, no band paths
• Steepest descent only, no sophisticated minimizations
• Random starting guess only, no calculated guess of the density

Citation

A supplementary paper for eminus is available on arXiv. The following BibTeX key can be used

@Misc{Schulze2021,
  author    = {Schulze, Wanja T. and Schwalbe, Sebastian and Trepte, Kai and Gr{\"a}fe, Stefanie},
  title     = {eminus -- Pythonic electronic structure theory},
  year      = {2024},
  doi       = {10.48550/arXiv.2410.19438},
  publisher = {arXiv},
}