PyCC

A Python-based coupled cluster implementation. Current capabilities include:

• Spin-adapted CCD, CC2, CCSD, CCSD(T), and CC3 energies
• Triples-drivers for various approximate triples methods
• RHF-CC2 and CCSD and densities
• EOM-CCSD
• Real-time (RT) CC2, CCSD, and CC3 with a selection of integrators
• GPU implementations for multiple methods
• Single- and mixed-precision arithmetic
• PAO-, PNO-, and PNO++-CCSD energies RT-CC

Future plans:

• Linear and quadratic response functions
• CC2 and CC3 excited states
• Analytic gradients

Notes on PNO-CC: https://github.com/JoseMadriaga/Notes/blob/main/LocalCCSD.pdf

This repository is currently under development. To do a developmental install, download this repository and type pip install -e . in the repository directory.

This package requires the following:

• psi4
• numpy
• opt_einsum
• scipy
• pytorch

Authors

T. Daniel Crawford, Benjamin G. Peyton, Zhe Wang, Jose Madriaga

Copyright

Copyright (c) 2024, T. Daniel Crawford

Acknowledgements

Project structure based on the MolSSI's Computational Molecular Science Python Cookiecutter Version 1.5.