Forte is an open-source suite of state-of-the-art quantum chemistry methods applicable to chemical systems with strongly correlated electrons. The code is written as a plugin to Psi4 in C++ with C++17 functionality, and it takes advantage of shared memory parallelism throughout.
In general, Forte is composed of two types of methods: 1. Active space solvers 1. Dynamical correlation solvers
| Active space solvers | Abbreviation |
|---|---|
| Full/complete active space configuration interaction | FCI/CASCI |
| Adaptive configuration interaction | ACI |
| Projector configuration interaction | PCI |
| Dynamical correlation solvers | Abbreviation |
|---|---|
| Driven similarity renormalization group | DSRG |
| Second-order DSRG multireference perturbation theory | DSRG-MRPT2 |
| Third-order DSRG multireference perturbation theory | DSRG-MRPT3 |
| Multireference DSRG with singles and doubles | MR-LDSRG(2) |
Note that the active space solvers, notably FCI, ACI, and PCI can operate within the full orbital basis defined by the user-selected basis set. In this case, these methods also recover dynamical correlation.
In order to run Forte, the following are required: - A Recent version of Psi4 - CMake version 3.0 or higher - The tensor library Ambit