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:

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 to true, 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 to determinants 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 to true.

Needs:

  • do_pt2

  • is_zmq_slave

  • json_int_fmt

  • json_unit

  • mo_two_e_integrals_in_map

  • n_states

  • psi_coef

  • psi_det

  • pt2_min_parallel_tasks

Calls:

  • json_close()

  • run_cipsi()

  • run_slave_cipsi()

  • run_stochastic_cipsi()

Touches:

  • ci_electronic_energy

  • ci_electronic_energy

  • ci_energy

  • ci_electronic_energy

  • psi_configuration

  • n_det

  • n_det_generators

  • n_det_selectors

  • c0_weight

  • distributed_davidson

  • psi_coef

  • psi_det_sorted_bit

  • psi_configuration

  • psi_det

  • psi_det_size

  • psi_det_sorted_bit

  • psi_energy

  • 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