fci
Selected Full Configuration Interaction with stochastic selection and PT2.
This program performs a CIPSI-like selected CI using a stochastic scheme for both the selection of the important Slater determinants and the computation of the PT2 correction. This CIPSI-like algorithm will be performed for the lowest states of the variational space (see
determinants n_states
). The FCI program will stop when reaching at least one the two following conditions:
number of Slater determinants >
determinants n_det_max
abs(PT2) less than
perturbation pt2_max
The following other options can be of interest:
determinants read_wf
When set to
false
, the program starts with a ROHF-like Slater determinant as a guess wave function. When set totrue
, the program starts with the wave function(s) stored in the EZFIO directory as guess wave function(s).determinants s2_eig
When set to
true
, the selection will systematically add all the necessary Slater determinants in order to have a pure spin wave function with an \(\widehat{S^2}\) value corresponding todeterminants expected_s2
.For excited states calculations, it is recommended to start with cis or cisd guess wave functions, eventually in a restricted set of MOs, and to set
determinants s2_eig
totrue
.Needs:
do_pt2
is_zmq_slave
mo_two_e_integrals_in_map
psi_coef
psi_det
Calls:
run_cipsi()
run_slave_cipsi()
run_stochastic_cipsi()
Touches:
ci_electronic_energy
ci_electronic_energy
ci_energy
ci_electronic_energy
n_det
n_iter
psi_occ_pattern
c0_weight
distributed_davidson
psi_coef
psi_det_sorted_bit
psi_det
psi_det_size
psi_det_sorted_bit
psi_energy
psi_occ_pattern
psi_energy
pt2_e0_denominator
pt2_match_weight
pt2_overlap
pt2_stoch_istate
read_wf
selection_weight
state_average_weight
threshold_davidson_pt2
threshold_generators
variance_match_weight