cis

This module contains a CIS program.

The user point of view

The cis program performs the CI to obtain the ROHF reference + all single 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 guesses 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’s point of view

This module was built by setting the following rules:

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

  • All generated singly excited 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 CIS energy

Programs

Subroutines / functions

h_apply_cis:

File : h_apply.irp.f_shell_13

subroutine H_apply_cis()

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

Calls:

  • build_fock_tmp()

  • copy_h_apply_buffer_to_wf()

  • dsort()

  • h_apply_cis_diexc()

  • h_apply_cis_monoexc()

  • make_s2_eigenfunction()

  • wall_time()

Touches:

  • n_det

  • psi_occ_pattern

  • c0_weight

  • psi_coef

  • psi_det_sorted_bit

  • psi_det

  • psi_det_size

  • psi_det_sorted_bit

  • psi_occ_pattern

h_apply_cis_diexc:

File : h_apply.irp.f_shell_13

subroutine H_apply_cis_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_cis()

Calls:

  • h_apply_cis_diexcp()

h_apply_cis_diexcorg:

File : h_apply.irp.f_shell_13

subroutine H_apply_cis_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_cis_diexcp()

Calls:

  • bitstring_to_list_ab()

  • fill_h_apply_buffer_no_selection()

h_apply_cis_diexcp:

File : h_apply.irp.f_shell_13

subroutine H_apply_cis_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_cis_diexc()

Calls:

  • h_apply_cis_diexcorg()

h_apply_cis_monoexc:

File : h_apply.irp.f_shell_13

subroutine H_apply_cis_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_cis()

Calls:

  • bitstring_to_list_ab()

  • fill_h_apply_buffer_no_selection()

h_apply_cis_sym:

File : h_apply.irp.f_shell_13

subroutine H_apply_cis_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

Calls:

  • build_fock_tmp()

  • copy_h_apply_buffer_to_wf()

  • dsort()

  • h_apply_cis_sym_diexc()

  • h_apply_cis_sym_monoexc()

  • make_s2_eigenfunction()

  • wall_time()

Touches:

  • n_det

  • psi_occ_pattern

  • c0_weight

  • psi_coef

  • psi_det_sorted_bit

  • psi_det

  • psi_det_size

  • psi_det_sorted_bit

  • psi_occ_pattern

h_apply_cis_sym_diexc:

File : h_apply.irp.f_shell_13

subroutine H_apply_cis_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_cis_sym()

Calls:

  • h_apply_cis_sym_diexcp()

h_apply_cis_sym_diexcorg:

File : h_apply.irp.f_shell_13

subroutine H_apply_cis_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_cis_sym_diexcp()

Calls:

  • bitstring_to_list_ab()

  • connected_to_hf()

  • fill_h_apply_buffer_no_selection()

h_apply_cis_sym_diexcp:

File : h_apply.irp.f_shell_13

subroutine H_apply_cis_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_cis_sym_diexc()

Calls:

  • h_apply_cis_sym_diexcorg()

h_apply_cis_sym_monoexc:

File : h_apply.irp.f_shell_13

subroutine H_apply_cis_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_cis_sym()

Calls:

  • bitstring_to_list_ab()

  • connected_to_hf()

  • fill_h_apply_buffer_no_selection()