cisd

This module contains a CI of single and double excitations.

The user point of view

The cisd program performs the CI of the ROHF-like + all single and double excitations on top of it. This program can be very useful to :

  • Ground state calculations: generate a guess for the ground state wave function if one is not sure that the scf() program gave the lowest SCF solution. In combination with save_natorb() it can produce new MOs in order to reperform an scf() optimization.

  • Excited states calculations: generate guess for all the determinants n_states wave functions, that will be used by the fci() program.

The main keywords/options to be used are:

The programmer point of view

This module have been built by setting the following rules:

  • The only generator determinant is the Hartree-Fock (single-reference method)

  • All generated determinants are included in the wave function (no perturbative selection)

These rules are set in the H_apply.irp.f file.

EZFIO parameters

energy

Variational CISD energy

lcc_energy

lccsd energy

Programs

Providers

lccsd_coef

File : lccsd_prov.irp.f

double precision, allocatable   :: lccsd_coef   (N_det,N_states)
double precision, allocatable   :: lccsd_energies       (N_states)

Needs:

  • big_array_coulomb_integrals

  • big_array_coulomb_integrals

  • davidson_sze_max

  • disk_based_davidson

  • mo_integrals_map

  • mo_two_e_integrals_in_map

  • n_det

  • n_int

  • n_states

  • n_states_diag

  • nproc

  • nthreads_davidson

  • psi_det

  • qp_max_mem

  • ref_bitmask

  • state_following

  • threshold_davidson

lccsd_energies

File : lccsd_prov.irp.f

double precision, allocatable   :: lccsd_coef   (N_det,N_states)
double precision, allocatable   :: lccsd_energies       (N_states)

Needs:

  • big_array_coulomb_integrals

  • big_array_coulomb_integrals

  • davidson_sze_max

  • disk_based_davidson

  • mo_integrals_map

  • mo_two_e_integrals_in_map

  • n_det

  • n_int

  • n_states

  • n_states_diag

  • nproc

  • nthreads_davidson

  • psi_det

  • qp_max_mem

  • ref_bitmask

  • state_following

  • threshold_davidson

Subroutines / functions

get_lccsd_2:

File : lccsd.irp.f

subroutine get_lccsd_2

Needs:

  • ha_to_ev

  • lccsd_coef

  • n_det

  • n_states

  • psi_coef

  • save_threshold

Called by:

  • run()

Calls:

  • ezfio_set_cisd_lcc_energy()

  • save_wavefunction_truncated()

Touches:

  • psi_coef

h_apply_cisd:

File : h_apply.irp.f_shell_12

subroutine H_apply_cisd()

Calls H_apply on the HF determinant and selects all connected single and double excitations (of the same symmetry). Auto-generated by the generate_h_apply script.

Needs:

  • generators_bitmask

  • h_apply_buffer_allocated

  • mo_num

  • mo_two_e_integrals_in_map

  • n_det

  • n_det_generators

  • n_int

  • n_states

  • psi_coef

  • psi_det_generators

  • psi_det

  • psi_det_generators

  • s2_eig

Called by:

  • run()

  • run_cisd()

Calls:

  • build_fock_tmp()

  • copy_h_apply_buffer_to_wf()

  • dsort()

  • h_apply_cisd_diexc()

  • h_apply_cisd_monoexc()

  • make_s2_eigenfunction()

  • wall_time()

Touches:

  • psi_configuration

  • n_det

  • c0_weight

  • psi_coef

  • psi_det_sorted_bit

  • psi_configuration

  • psi_det

  • psi_det_size

  • psi_det_sorted_bit

h_apply_cisd_diexc:

File : h_apply.irp.f_shell_12

subroutine H_apply_cisd_diexc(key_in, key_prev, hole_1,particl_1, hole_2, particl_2, fock_diag_tmp, i_generator, iproc_in  )

Needs:

  • mo_num

  • n_det

  • n_int

Called by:

  • h_apply_cisd()

Calls:

  • h_apply_cisd_diexcp()

h_apply_cisd_diexcorg:

File : h_apply.irp.f_shell_12

subroutine H_apply_cisd_diexcOrg(key_in,key_mask,hole_1,particl_1,hole_2, particl_2, fock_diag_tmp, i_generator, iproc_in  )

Generate all double excitations of key_in using the bit masks of holes and particles. Assume N_int is already provided.

Needs:

  • elec_alpha_num

  • mo_num

  • n_int

Called by:

  • h_apply_cisd_diexcp()

Calls:

  • bitstring_to_list_ab()

  • fill_h_apply_buffer_no_selection()

h_apply_cisd_diexcp:

File : h_apply.irp.f_shell_12

subroutine H_apply_cisd_diexcP(key_in, fs1, fh1, particl_1, fs2, fh2, particl_2, fock_diag_tmp, i_generator, iproc_in  )

Needs:

  • mo_num

  • n_det

  • n_int

Called by:

  • h_apply_cisd_diexc()

Calls:

  • h_apply_cisd_diexcorg()

h_apply_cisd_monoexc:

File : h_apply.irp.f_shell_12

subroutine H_apply_cisd_monoexc(key_in, hole_1,particl_1,fock_diag_tmp,i_generator,iproc_in  )

Generate all single excitations of key_in using the bit masks of holes and particles. Assume N_int is already provided.

Needs:

  • elec_alpha_num

  • mo_num

  • n_int

Called by:

  • h_apply_cisd()

Calls:

  • bitstring_to_list_ab()

  • fill_h_apply_buffer_no_selection()

h_apply_cisd_sym:

File : h_apply.irp.f_shell_12

subroutine H_apply_cisd_sym()

Calls H_apply on the HF determinant and selects all connected single and double excitations (of the same symmetry). Auto-generated by the generate_h_apply script.

Needs:

  • generators_bitmask

  • h_apply_buffer_allocated

  • mo_num

  • mo_two_e_integrals_in_map

  • n_det

  • n_det_generators

  • n_int

  • n_states

  • psi_coef

  • psi_det_generators

  • psi_det

  • psi_det_generators

  • s2_eig

Called by:

  • run()

  • run_cisd()

Calls:

  • build_fock_tmp()

  • copy_h_apply_buffer_to_wf()

  • dsort()

  • h_apply_cisd_sym_diexc()

  • h_apply_cisd_sym_monoexc()

  • make_s2_eigenfunction()

  • wall_time()

Touches:

  • psi_configuration

  • n_det

  • c0_weight

  • psi_coef

  • psi_det_sorted_bit

  • psi_configuration

  • psi_det

  • psi_det_size

  • psi_det_sorted_bit

h_apply_cisd_sym_diexc:

File : h_apply.irp.f_shell_12

subroutine H_apply_cisd_sym_diexc(key_in, key_prev, hole_1,particl_1, hole_2, particl_2, fock_diag_tmp, i_generator, iproc_in  )

Needs:

  • mo_num

  • n_det

  • n_int

Called by:

  • h_apply_cisd_sym()

Calls:

  • h_apply_cisd_sym_diexcp()

h_apply_cisd_sym_diexcorg:

File : h_apply.irp.f_shell_12

subroutine H_apply_cisd_sym_diexcOrg(key_in,key_mask,hole_1,particl_1,hole_2, particl_2, fock_diag_tmp, i_generator, iproc_in  )

Generate all double excitations of key_in using the bit masks of holes and particles. Assume N_int is already provided.

Needs:

  • elec_alpha_num

  • mo_num

  • n_int

Called by:

  • h_apply_cisd_sym_diexcp()

Calls:

  • bitstring_to_list_ab()

  • connected_to_hf()

  • fill_h_apply_buffer_no_selection()

h_apply_cisd_sym_diexcp:

File : h_apply.irp.f_shell_12

subroutine H_apply_cisd_sym_diexcP(key_in, fs1, fh1, particl_1, fs2, fh2, particl_2, fock_diag_tmp, i_generator, iproc_in  )

Needs:

  • mo_num

  • n_det

  • n_int

Called by:

  • h_apply_cisd_sym_diexc()

Calls:

  • h_apply_cisd_sym_diexcorg()

h_apply_cisd_sym_monoexc:

File : h_apply.irp.f_shell_12

subroutine H_apply_cisd_sym_monoexc(key_in, hole_1,particl_1,fock_diag_tmp,i_generator,iproc_in  )

Generate all single excitations of key_in using the bit masks of holes and particles. Assume N_int is already provided.

Needs:

  • elec_alpha_num

  • mo_num

  • n_int

Called by:

  • h_apply_cisd_sym()

Calls:

  • bitstring_to_list_ab()

  • connected_to_hf()

  • fill_h_apply_buffer_no_selection()

run_cisd:

File : cisd_routine.irp.f

subroutine run_cisd

Needs:

  • ci_electronic_energy

  • ci_energy

  • n_det

  • n_states

  • pseudo_sym

  • psi_coef

Calls:

  • ezfio_set_cisd_energy()

  • h_apply_cisd()

  • h_apply_cisd_sym()

  • save_wavefunction()

Touches:

  • psi_configuration

  • n_det

  • c0_weight

  • psi_coef

  • psi_det_sorted_bit

  • psi_configuration

  • psi_det

  • psi_det_size

  • psi_det_sorted_bit