The Python-based Simulations of Chemistry Framework (PySCF)

TL;DR

PySCF is a flexible, efficient, Python-based electronic structure platform designed for ease of development and diverse computational workflows, supporting various quantum chemistry methods and system types.

Contribution

This paper introduces PySCF, a new quantum chemistry software that combines Python simplicity with C efficiency, enabling flexible and extensible electronic structure simulations.

Findings

PySCF achieves computational efficiency comparable to traditional C/Fortran programs.

It supports a wide range of systems including finite, periodic, and low-dimensional.

The package emphasizes code simplicity and extensibility for method development.

Abstract

PySCF is a general-purpose electronic structure platform designed from the ground up to emphasize code simplicity, both to aid new method development, as well as for flexibility in computational workflow. The package provides a wide range of tools to support simulations of finite size systems, extended systems with periodic boundary conditions, low dimensional periodic systems, and custom Hamiltonians, using mean-field and post-mean-field methods with standard Gaussian basis functions. To ensure easy of extensibility, PySCF uses the Python language to implement almost all its features, while computationally critical paths are implemented with heavily optimized C routines. Using this combined Python/C implementation, the package is as efficient as the best existing C or Fortran based quantum chemistry programs. In this paper we document the capabilities and design philosophy of the current version of the PySCF package.