Pythonic Black-box Electronic Structure Tool (PyBEST). An open-source Python platform for electronic structure calculations at the interface between chemistry and physics

Pythonic Black-box Electronic Structure Tool (PyBEST) represents a fully-fledged modern electronic structure software package developed at Nicolaus Copernicus University in Toru?. The provides an efficient and reliable platform for calculations the interface between chemistry physics using unique methods, analysis tools, visualization. Examples are (orbital-optimized) pCCD-based models ground- excited-states as well quantum entanglement framework based on single-orbital entropy orbital-pair mutual information. PyBEST is written primarily Python programming language with additional parts C??, which interfaced Pybind11, lightweight header-only library. By construction, easy to use, code, other packages. Moreover, its modularity allows us conveniently host packages libraries future releases enhance performance. methods available tested half-filled 1-D model Hamiltonian. capability of perform large-scale demonstrated vitamin B12 compound. investigated molecule composed 190 electrons 777 orbitals orbital optimization within pCCD correlation performed first time. Program title: CPC Library link program files: https://doi.org/10.17632/xf9kb7yfwr.1 Developer’s repository link: https://zenodo.org/record/3925278#.X5KAZS8Rq6s Licensing provisions: GNU General Public License 3 Programming language: Python, C?? Nature problem: Efficient modeling structures featuring both weakly- strongly-correlated electrons. Small- quantum-mechanical problems comprising chemical Hamiltonians. Specifically, potential energy surfaces complex including bond breaking/formation, elucidating through picture interacting orbitals, describing noncovalent interactions, ultra-cold trapped gases, variety applications interdisciplinary mechanical-based problems. Solution method: Modular implementation series unconventional (and conventional) ansatz solve Schrödinger equation. These include description excited-states, determination interaction energies, interpretation wavefunctions. All modules implemented language, where bottleneck operations handled by code Pybind11 (wavefunction) modular make very alternative existing Additional comments restrictions unusual features: features (pCCD post-pCCD methods) that not any chemistry/physics package. It also includes general module supports selected methods. designed be use in. Due (for instance tensor contraction engine), new can straightforwardly imported exploited without changing wavefunction directly. References: http://pybest.fizyka.umk.pl