- Coupled cluster calculations using a wide range of ansatzes, as summarised below
- Lambda equation solver
- Equation-of-motion solver
- Density matrices
- Frozen and active space constraints
- Brueckner orbital calculations
- Frozen natural orbital calculations
- Single- and mixed-precision calculations
The following table summarises the available methods and routines for the ansatz currently treated by code generation, in the three spin cases:
| Ansatz | E | T | Λ | IP | EA | EE | DM1 | DM2 | BDM |
|---|---|---|---|---|---|---|---|---|---|
| MP2 | RUG | - | - | RUG | RUG | G | RUG | RUG | - |
| MP3 | RUG | - | |||||||
| CCD | RUG | RUG | RUG | RUG | RUG | G | RUG | RUG | - |
| CCSD | RUG | RUG | RUG | RUG | RUG | G | RUG | RUG | - |
| CCSDT | RUG | RUG | RUG | RUG | RUG | - | |||
| CCSDTQ | g | g | - | ||||||
| CCSD(T) | RuG | RuG | - | ||||||
| CCSDt | RG | RG | - | ||||||
| CCSDt' | RUG | RUG | - | ||||||
| CC2 | RUG | RUG | RUG | RUG | RUG | G | RUG | RUG | - |
| CC3 | RUG | RUG | - | ||||||
| QCISD | RUG | RUG | - | ||||||
| DCD | RU | RU | - | ||||||
| DCSD | RU | RU | - | ||||||
| DF-CCD | RU | RU | RU | RU | RU | RU | RU | - | |
| DF-CCSD | RU | RU | RU | RU | RU | RU | RU | - | |
| DF-CC2 | RU | RU | RU | RU | RU | RU | RU | - | |
| DF-QCISD | RU | RU | - | ||||||
| DF-DCD | RU | RU | - | ||||||
| DF-DCSD | RU | RU | - | ||||||
| CCSD-S-1-1 | RUG | RUG | RUG | RUG | RUG | RUG | |||
| CCSD-SD-1-1 | RUG | RUG | RUG | RUG | RUG | RUG | |||
| CCSD-SD-1-2 | RUG | RUG | RUG | RUG | RUG | RUG |
- R, U, G indicate availability of restricted, unrestricted, and generalised codes.
- Capital letters (R rather than r) indicates that the expressions are optimised for contraction order and subexpression elimination.
- DF in the ansatz name indicates methods specialised for density-fitted integrals.
- E is the correlation energy.
- T, Λ are the excitation and de-excitation amplitude availabilities, respectively, the former allowing the coupled cluster solver and the latter allowing the lambda solver.
- IP, EA, EE indicate availability of the corresponding equation of motion (EOM) functionalities.
- DM1, DM2 indicate availability of the one- and two-particle reduced density matrices.
- BDM availability includes the single boson density matrix, bosonic one-particle reduced density matrix, and the electron-boson coupling reduced density matrix.