forte2.sci.sci#

Module Contents#

class forte2.sci.sci.SelectedCISolver#

Bases: forte2.base_classes.CIBase

A general configuration interaction (CI) solver class. This solver is can be called iteratively, e.g., in a MCSCF loop or a DSRG reference relaxation loop.

Parameters:

sci_paramsSelectedCIParams or list[SelectedCIParams], optional: Parameters specific to the selected CI algorithm. If a list is provided, it should have one entry per state. If only a single SelectedCIParams is provided, it will be used for all states.
davidson_liu_paramsDavidsonLiuParams or list[DavidsonLiuParams], optional: Parameters for the Davidson-Liu iterative eigensolver. If a list is provided, it should have one entry per state. If only a single DavidsonLiuParams is provided, it will be used for all states.
do_test_rdmsbool, optional, default=False: If True, compute and test the reduced density matrices (RDMs) after the CI calculation.
log_levelint, optional: The logging level for the CI solver. Defaults to the global logger’s verbosity level.

Attributes:

sub_solverslist[_SelectedCISingleStateSolver]: A list of CI solvers for each state in the state-averaged CI.
evar/evals_[per_solver/flat]list[NDArray] / NDArray: The variational eigenvalues (energies) computed by each sub-solver / concatenated into a single array.
ept2_var_[per_solver/flat]list[NDArray] / NDArray: The PT2 correction due to the new variational determinants, computed by each sub-solver / concatenated into a single array.
ept2_pt_[per_solver/flat]list[NDArray] / NDArray: The PT2 correction due to the perturbative determinants, computed by each sub-solver / concatenated into a single array.
etot_[per_solver/flat]list[NDArray] / NDArray: The total energy (variational + PT2) computed by each sub-solver / concatenated into a single array.
ENDArray: Alias for evar_flat, the variational energies of the CI roots.
E_pt2NDArray: The total PT2 correction (variational + perturbative) for each CI root.
E_totNDArray: Alias for etot_flat, the total energies of the CI roots.
E_avgfloat: The average variational energy computed from the state-averaged CI roots.

sci_params: forte2.base_classes.params.SelectedCIParams | list[forte2.base_classes.params.SelectedCIParams]#

davidson_liu_params: forte2.base_classes.params.DavidsonLiuParams | list[forte2.base_classes.params.DavidsonLiuParams]#

do_test_rdms: bool = False#

log_level: int = 4#

run()#

compute_average_energy()#

Compute the average energy from the CI roots using the weights.

Returns:

float: Average energy of the CI roots.

make_sd_1rdm(left_root: int, right_root: int | None = None)#: Make the spin-dependent one-particle RDM for two absolute CI roots.

make_sf_1rdm(left_root: int, right_root: int | None = None)#: Make the spin-free one-particle RDM for two absolute CI roots.

make_1rdm(left_root: int, right_root: int | None = None)#: Make the spin-free one-particle RDM for two absolute CI roots.

make_average_1rdm()#

Make the average spin-free one-particle RDM from the CI vectors.

Returns:

NDArray: Average spin-free one-particle RDM.

make_average_2rdm()#

Make the average spin-free two-particle RDM from the CI vectors.

Returns:

NDArray: Average spin-free two-particle RDM.

set_ints(scalar, oei, tei)#

Set the active-space integrals for the CI solver.

Parameters:

scalarfloat: The scalar energy term.
oeiNDArray: One-electron active-space integrals in the MO basis.
teiNDArray: Two-electron active-space integrals in the MO basis.

compute_natural_occupation_numbers()#

Compute the natural occupation numbers for the CI states.

Returns:

(norb, nroot) NDArray: The natural occupation numbers for each root.

get_top_determinants(n=5)#

Get the top n determinants for each root based on their coefficients in the CI vector.

Parameters:

nint, optional, default=5: The number of top determinants to return.

Returns:

top_detslist[list[tuple[Determinant, float]]]]: top_dets[i] contains a list of tuples (Determinant, coefficient) for the i-th root.

compute_transition_properties(C=None)#: Compute the transition dipole moments and oscillator strengths from the spin-free 1-TDMs. The results are stored in self.transition_dipoles and self.oscillator_strengths.

reset_eigensolver()#

get_convergence_status()#

class forte2.sci.sci.SelectedCI#

Bases: SelectedCISolver

Selected CI solver specialized for a single CI calculation. (i.e., not used in a loop). See SelectedCISolver for all parameters and attributes.

die_if_not_converged: bool = True#

final_orbital: str = 'original'#

do_transition_dipole: bool = False#

log_level: int = 3#

run()#