SCINE - AutoCAS

Introduction

SCINE autoCAS automates the crucial active-orbital-space selection step in multi-configurational calculations. Based on orbital entanglement measures derived from an approximate DMRG wave function, it identifies all strongly correlated orbitals to be included in the active space of a final, converged calculation. All steps can be carried out in a fully automated fashion.

Installation

Currently autoCAS can be installed via pip or manually with git and pip (see sections below).

Basic Requirements

AutoCAS utilizes a couple of third-party packages, which are defined in the requirements.txt.

All requirements are automatically installed by installing autoCAS over one of the following methods.

pip

Prerequisites

1. python3.6+

Install

This methods allows you to install the package via pip.

pip install scine-autocas

Git + pip

Prerequisites

1. git
2. python3.6+

Install

This methods requires you to first clone the repository and install the package over pip.

git clone <autocas-repo>
cd autoCAS
pip install -r requirements.txt
pip install .

Set up OpenMolcas

Up to this point OpenMolcas does not provide any way to call itself from a native Python interfaces. Hence, autoCAS calls OpenMolcas directly over pymolcas. In order to do so, please set the environment variable MOLCAS pointing to the build directory.

export MOLCAS=/path/to/Molcas/build

Quickstart

After installing autoCAS it can be started from the command line. To show all possible options, please run:

python3 -m scine_autocas -h

For example, autoCAS can be started by passing a valid XYZ file to it, and running all calculations with the corresponding defaults.

python3 -m scine_autocas -x <molecule.xyz>

To pass a basis set, a different interface or enable the creation of entanglement diagrams the following directives can be passed:

python3 -m scine_autocas --xyz_file <molecule.xyz> --basis_set cc-pvtz --plot --interface Molcas

However we would strongly recommend providing a .yml-input file, to make calculations reproducible and allowing higher customization of autoCAS.

License and Copyright Information

AutoCAS is distributed under the BSD 3-clause "New" or "Revised" License. For more license and copyright information, see the file LICENSE.txt in the repository.

How to Cite

When publishing results obtained with the autoCAS program, please cite the corresponding release as archived on Zenodo (please use the DOI of the respective release) and the following publications:

• Primary reference: C. J. Stein and M. Reiher, "autoCAS: A Program for Fully Automated Multiconfigurational Calculations", J. Comput. Chem., 2019, 40, 2216-2226.
• Original presentation of the approach: C. J. Stein and M. Reiher, "Automated Selection of Active Orbital Spaces”", J. Chem. Theory Comput., 2016, 12, 1760.
• Automated active space selection with multi-reference perturbation theory: C. J. Stein, V. von Burg and M. Reiher, "The Delicate Balance of Static and Dynamic Electron Correlation", J. Chem. Theory Comput., 2016, 12, 3764.
• Multi-configurational diagnostic: C. J. Stein and M. Reiher, "Measuring Multi-Configurational Character by Orbital Entanglement", Mol. Phys., 2017, 115, 2110.
• Excited states and reaction paths: C. J. Stein and M. Reiher, "Automated Identification of Relevant Frontier Orbitals for Chemical Compounds and Processes", Chimia, 2017, 71, 170.
• SCINE framework: T. Weymuth, J. P. Unsleber, P. L. Türtscher, M. Steiner, J.-G. Sobez, C. H. Müller, M. Mörchen, V. Klasovita, S. A. Grimmel, M. Eckhoff, K.-S. Csizi, F. Bosia, M. Bensberg, M. Reiher, "SCINE—Software for chemical interaction networks", J. Chem. Phys., 2024, 160, 222501 (DOI 10.1063/5.0206974).

Support and Contact

In case you should encounter problems or bugs, please write a short message to autocas@phys.chem.ethz.ch.