.. _module_perturbation: .. program:: perturbation .. default-role:: option ============ perturbation ============ All subroutines in ``*.irp.f`` starting with `pt2_` in the current directory are perturbation computed using the routine `i_H_psi`. Other cases are not allowed. The arguments of the `pt2_` are always: .. code-block:: fortran subroutine pt2_...( & psi_ref, & psi_ref_coefs, & E_refs, & det_pert, & c_pert, & e_2_pert, & H_pert_diag, & Nint, & Ndet, & N_st ) integer , intent(in) :: Nint,Ndet,N_st integer(bit_kind), intent(in) :: psi_ref(Nint,2,Ndet) double precision , intent(in) :: psi_ref_coefs(Ndet,N_st) double precision , intent(in) :: E_refs(N_st) integer(bit_kind), intent(in) :: det_pert(Nint,2) double precision , intent(out) :: c_pert(N_st),e_2_pert(N_st),H_pert_diag `psi_ref` bitstring of the determinants present in the various `N_st` states `psi_ref_coefs` coefficients of the determinants on the various `N_st` states `E_refs` Energy of the various `N_st` states `det_pert` Perturber determinant `c_pert` Perturbative coefficients for the various states `e_2_pert` Perturbative energetic contribution for the various states `H_pert_diag` Diagonal |H| matrix element of the perturber `Nint` Should be equal to `N_int` `Ndet` Number of determinants `i` in |Psi| on which we apply `N_st` Number of states EZFIO parameters ---------------- .. option:: do_pt2 If `True`, compute the |PT2| contribution Default: True .. option:: pt2_max The selection process stops when the largest |PT2| (for all the state) is lower than `pt2_max` in absolute value Default: 0.0001 .. option:: variance_max The selection process stops when the largest variance (for all the state) is lower than `variance_max` in absolute value Default: 0.0 .. option:: pt2_min_parallel_tasks Minimum number of tasks in PT2 calculation Default: 1 .. option:: pt2_relative_error Stop stochastic |PT2| when the relative error is smaller than `pT2_relative_error` Default: 0.002 .. option:: correlation_energy_ratio_max The selection process stops at a fixed correlation ratio (useful for getting same accuracy between molecules). Defined as :math:`(E_{CI}-E_{HF})/(E_{CI}+E_{PT2} - E_{HF})`. Default: 1.00 .. option:: h0_type Type of denominator in PT2. [EN | CFG | HF] Default: EN Providers --------- .. c:var:: max_exc_pert File : :file:`perturbation/exc_max.irp.f` .. code:: fortran integer :: max_exc_pert .. c:var:: selection_criterion File : :file:`perturbation/selection.irp.f` .. code:: fortran double precision :: selection_criterion double precision :: selection_criterion_min double precision :: selection_criterion_factor Threshold to select determinants. Set by selection routines. .. c:var:: selection_criterion_factor File : :file:`perturbation/selection.irp.f` .. code:: fortran double precision :: selection_criterion double precision :: selection_criterion_min double precision :: selection_criterion_factor Threshold to select determinants. Set by selection routines. .. c:var:: selection_criterion_min File : :file:`perturbation/selection.irp.f` .. code:: fortran double precision :: selection_criterion double precision :: selection_criterion_min double precision :: selection_criterion_factor Threshold to select determinants. Set by selection routines. .. c:var:: var_pt2_ratio File : :file:`perturbation/var_pt2_ratio_provider.irp.f` .. code:: fortran double precision :: var_pt2_ratio The selection process stops when the energy ratio variational/(variational+PT2) is equal to var_pt2_ratio Needs: .. hlist:: :columns: 3 * :c:data:`correlation_energy_ratio_max` Subroutines / functions ----------------------- .. c:function:: fill_h_apply_buffer_selection: File : :file:`perturbation/selection.irp.f` .. code:: fortran subroutine fill_H_apply_buffer_selection(n_selected,det_buffer,e_2_pert_buffer,coef_pert_buffer, N_st,Nint,iproc,select_max_out) Fill the H_apply buffer with determiants for the selection Needs: .. hlist:: :columns: 3 * :c:data:`h_apply_buffer_allocated` * :c:data:`n_det` * :c:data:`n_int` * :c:data:`selection_criterion` Calls: .. hlist:: :columns: 3 * :c:func:`omp_set_lock` * :c:func:`omp_unset_lock` * :c:func:`resize_h_apply_buffer` .. c:function:: perturb_buffer_by_mono_dummy: File : :file:`perturbation/perturbation.irp.f_shell_13` .. code:: fortran subroutine perturb_buffer_by_mono_dummy(i_generator,buffer,buffer_size,e_2_pert_buffer,coef_pert_buffer,sum_e_2_pert,sum_norm_pert,sum_H_pert_diag,N_st,Nint,key_mask,fock_diag_tmp,electronic_energy) Apply pertubration ``dummy`` to the buffer of determinants generated in the H_apply routine. Needs: .. hlist:: :columns: 3 * :c:data:`mo_num` * :c:data:`n_det` * :c:data:`n_det_generators` * :c:data:`n_det_selectors` * :c:data:`psi_det_generators` * :c:data:`psi_selectors` Calls: .. hlist:: :columns: 3 * :c:func:`create_minilist` * :c:func:`create_minilist_find_previous` * :c:func:`pt2_dummy` .. c:function:: perturb_buffer_by_mono_epstein_nesbet: File : :file:`perturbation/perturbation.irp.f_shell_13` .. code:: fortran subroutine perturb_buffer_by_mono_epstein_nesbet(i_generator,buffer,buffer_size,e_2_pert_buffer,coef_pert_buffer,sum_e_2_pert,sum_norm_pert,sum_H_pert_diag,N_st,Nint,key_mask,fock_diag_tmp,electronic_energy) Apply pertubration ``epstein_nesbet`` to the buffer of determinants generated in the H_apply routine. Needs: .. hlist:: :columns: 3 * :c:data:`mo_num` * :c:data:`n_det` * :c:data:`n_det_generators` * :c:data:`n_det_selectors` * :c:data:`psi_det_generators` * :c:data:`psi_selectors` Calls: .. hlist:: :columns: 3 * :c:func:`create_minilist` * :c:func:`create_minilist_find_previous` * :c:func:`pt2_epstein_nesbet` .. c:function:: perturb_buffer_by_mono_epstein_nesbet_2x2: File : :file:`perturbation/perturbation.irp.f_shell_13` .. code:: fortran subroutine perturb_buffer_by_mono_epstein_nesbet_2x2(i_generator,buffer,buffer_size,e_2_pert_buffer,coef_pert_buffer,sum_e_2_pert,sum_norm_pert,sum_H_pert_diag,N_st,Nint,key_mask,fock_diag_tmp,electronic_energy) Apply pertubration ``epstein_nesbet_2x2`` to the buffer of determinants generated in the H_apply routine. Needs: .. hlist:: :columns: 3 * :c:data:`mo_num` * :c:data:`n_det` * :c:data:`n_det_generators` * :c:data:`n_det_selectors` * :c:data:`psi_det_generators` * :c:data:`psi_selectors` Calls: .. hlist:: :columns: 3 * :c:func:`create_minilist` * :c:func:`create_minilist_find_previous` * :c:func:`pt2_epstein_nesbet_2x2` .. c:function:: perturb_buffer_by_mono_epstein_nesbet_2x2_no_ci_diag: File : :file:`perturbation/perturbation.irp.f_shell_13` .. code:: fortran subroutine perturb_buffer_by_mono_epstein_nesbet_2x2_no_ci_diag(i_generator,buffer,buffer_size,e_2_pert_buffer,coef_pert_buffer,sum_e_2_pert,sum_norm_pert,sum_H_pert_diag,N_st,Nint,key_mask,fock_diag_tmp,electronic_energy) Apply pertubration ``epstein_nesbet_2x2_no_ci_diag`` to the buffer of determinants generated in the H_apply routine. Needs: .. hlist:: :columns: 3 * :c:data:`mo_num` * :c:data:`n_det` * :c:data:`n_det_generators` * :c:data:`n_det_selectors` * :c:data:`psi_det_generators` * :c:data:`psi_selectors` Calls: .. hlist:: :columns: 3 * :c:func:`create_minilist` * :c:func:`create_minilist_find_previous` * :c:func:`pt2_epstein_nesbet_2x2_no_ci_diag` .. c:function:: perturb_buffer_by_mono_moller_plesset: File : :file:`perturbation/perturbation.irp.f_shell_13` .. code:: fortran subroutine perturb_buffer_by_mono_moller_plesset(i_generator,buffer,buffer_size,e_2_pert_buffer,coef_pert_buffer,sum_e_2_pert,sum_norm_pert,sum_H_pert_diag,N_st,Nint,key_mask,fock_diag_tmp,electronic_energy) Apply pertubration ``moller_plesset`` to the buffer of determinants generated in the H_apply routine. Needs: .. hlist:: :columns: 3 * :c:data:`mo_num` * :c:data:`n_det` * :c:data:`n_det_generators` * :c:data:`n_det_selectors` * :c:data:`psi_det_generators` * :c:data:`psi_selectors` Calls: .. hlist:: :columns: 3 * :c:func:`create_minilist` * :c:func:`create_minilist_find_previous` * :c:func:`pt2_moller_plesset` .. c:function:: perturb_buffer_by_mono_qdpt: File : :file:`perturbation/perturbation.irp.f_shell_13` .. code:: fortran subroutine perturb_buffer_by_mono_qdpt(i_generator,buffer,buffer_size,e_2_pert_buffer,coef_pert_buffer,sum_e_2_pert,sum_norm_pert,sum_H_pert_diag,N_st,Nint,key_mask,fock_diag_tmp,electronic_energy) Apply pertubration ``qdpt`` to the buffer of determinants generated in the H_apply routine. Needs: .. hlist:: :columns: 3 * :c:data:`mo_num` * :c:data:`n_det` * :c:data:`n_det_generators` * :c:data:`n_det_selectors` * :c:data:`psi_det_generators` * :c:data:`psi_selectors` Calls: .. hlist:: :columns: 3 * :c:func:`create_minilist` * :c:func:`create_minilist_find_previous` * :c:func:`pt2_qdpt` .. c:function:: perturb_buffer_dummy: File : :file:`perturbation/perturbation.irp.f_shell_13` .. code:: fortran subroutine perturb_buffer_dummy(i_generator,buffer,buffer_size,e_2_pert_buffer,coef_pert_buffer,sum_e_2_pert,sum_norm_pert,sum_H_pert_diag,N_st,Nint,key_mask,fock_diag_tmp,electronic_energy) Apply pertubration ``dummy`` to the buffer of determinants generated in the H_apply routine. Needs: .. hlist:: :columns: 3 * :c:data:`mo_num` * :c:data:`n_det_generators` * :c:data:`n_det_selectors` * :c:data:`psi_det_generators` * :c:data:`psi_selectors` Calls: .. hlist:: :columns: 3 * :c:func:`create_microlist` * :c:func:`create_minilist` * :c:func:`create_minilist_find_previous` * :c:func:`getmobiles` * :c:func:`pt2_dummy` .. c:function:: perturb_buffer_epstein_nesbet: File : :file:`perturbation/perturbation.irp.f_shell_13` .. code:: fortran subroutine perturb_buffer_epstein_nesbet(i_generator,buffer,buffer_size,e_2_pert_buffer,coef_pert_buffer,sum_e_2_pert,sum_norm_pert,sum_H_pert_diag,N_st,Nint,key_mask,fock_diag_tmp,electronic_energy) Apply pertubration ``epstein_nesbet`` to the buffer of determinants generated in the H_apply routine. Needs: .. hlist:: :columns: 3 * :c:data:`mo_num` * :c:data:`n_det_generators` * :c:data:`n_det_selectors` * :c:data:`psi_det_generators` * :c:data:`psi_selectors` Calls: .. hlist:: :columns: 3 * :c:func:`create_microlist` * :c:func:`create_minilist` * :c:func:`create_minilist_find_previous` * :c:func:`getmobiles` * :c:func:`pt2_epstein_nesbet` .. c:function:: perturb_buffer_epstein_nesbet_2x2: File : :file:`perturbation/perturbation.irp.f_shell_13` .. code:: fortran subroutine perturb_buffer_epstein_nesbet_2x2(i_generator,buffer,buffer_size,e_2_pert_buffer,coef_pert_buffer,sum_e_2_pert,sum_norm_pert,sum_H_pert_diag,N_st,Nint,key_mask,fock_diag_tmp,electronic_energy) Apply pertubration ``epstein_nesbet_2x2`` to the buffer of determinants generated in the H_apply routine. Needs: .. hlist:: :columns: 3 * :c:data:`mo_num` * :c:data:`n_det_generators` * :c:data:`n_det_selectors` * :c:data:`psi_det_generators` * :c:data:`psi_selectors` Calls: .. hlist:: :columns: 3 * :c:func:`create_microlist` * :c:func:`create_minilist` * :c:func:`create_minilist_find_previous` * :c:func:`getmobiles` * :c:func:`pt2_epstein_nesbet_2x2` .. c:function:: perturb_buffer_epstein_nesbet_2x2_no_ci_diag: File : :file:`perturbation/perturbation.irp.f_shell_13` .. code:: fortran subroutine perturb_buffer_epstein_nesbet_2x2_no_ci_diag(i_generator,buffer,buffer_size,e_2_pert_buffer,coef_pert_buffer,sum_e_2_pert,sum_norm_pert,sum_H_pert_diag,N_st,Nint,key_mask,fock_diag_tmp,electronic_energy) Apply pertubration ``epstein_nesbet_2x2_no_ci_diag`` to the buffer of determinants generated in the H_apply routine. Needs: .. hlist:: :columns: 3 * :c:data:`mo_num` * :c:data:`n_det_generators` * :c:data:`n_det_selectors` * :c:data:`psi_det_generators` * :c:data:`psi_selectors` Calls: .. hlist:: :columns: 3 * :c:func:`create_microlist` * :c:func:`create_minilist` * :c:func:`create_minilist_find_previous` * :c:func:`getmobiles` * :c:func:`pt2_epstein_nesbet_2x2_no_ci_diag` .. c:function:: perturb_buffer_moller_plesset: File : :file:`perturbation/perturbation.irp.f_shell_13` .. code:: fortran subroutine perturb_buffer_moller_plesset(i_generator,buffer,buffer_size,e_2_pert_buffer,coef_pert_buffer,sum_e_2_pert,sum_norm_pert,sum_H_pert_diag,N_st,Nint,key_mask,fock_diag_tmp,electronic_energy) Apply pertubration ``moller_plesset`` to the buffer of determinants generated in the H_apply routine. Needs: .. hlist:: :columns: 3 * :c:data:`mo_num` * :c:data:`n_det_generators` * :c:data:`n_det_selectors` * :c:data:`psi_det_generators` * :c:data:`psi_selectors` Calls: .. hlist:: :columns: 3 * :c:func:`create_microlist` * :c:func:`create_minilist` * :c:func:`create_minilist_find_previous` * :c:func:`getmobiles` * :c:func:`pt2_moller_plesset` .. c:function:: perturb_buffer_qdpt: File : :file:`perturbation/perturbation.irp.f_shell_13` .. code:: fortran subroutine perturb_buffer_qdpt(i_generator,buffer,buffer_size,e_2_pert_buffer,coef_pert_buffer,sum_e_2_pert,sum_norm_pert,sum_H_pert_diag,N_st,Nint,key_mask,fock_diag_tmp,electronic_energy) Apply pertubration ``qdpt`` to the buffer of determinants generated in the H_apply routine. Needs: .. hlist:: :columns: 3 * :c:data:`mo_num` * :c:data:`n_det_generators` * :c:data:`n_det_selectors` * :c:data:`psi_det_generators` * :c:data:`psi_selectors` Calls: .. hlist:: :columns: 3 * :c:func:`create_microlist` * :c:func:`create_minilist` * :c:func:`create_minilist_find_previous` * :c:func:`getmobiles` * :c:func:`pt2_qdpt` .. c:function:: pt2_dummy: File : :file:`perturbation/pt2_equations.irp.f_template_305` .. code:: fortran subroutine pt2_dummy (electronic_energy,det_ref,det_pert,fock_diag_tmp,c_pert,e_2_pert,H_pert_diag,Nint,ndet,N_st,minilist,idx_minilist,N_minilist) Dummy perturbation to add all connected determinants. Needs: .. hlist:: :columns: 3 * :c:data:`mo_num` * :c:data:`n_det_selectors` * :c:data:`psi_selectors` * :c:data:`psi_selectors_size` * :c:data:`selection_criterion` Called by: .. hlist:: :columns: 3 * :c:func:`perturb_buffer_by_mono_dummy` * :c:func:`perturb_buffer_dummy` Calls: .. hlist:: :columns: 3 * :c:func:`i_h_psi_minilist` .. c:function:: pt2_epstein_nesbet: File : :file:`perturbation/pt2_equations.irp.f_template_305` .. code:: fortran subroutine pt2_epstein_nesbet (electronic_energy,det_ref,det_pert,fock_diag_tmp,c_pert,e_2_pert,H_pert_diag,Nint,ndet,N_st,minilist,idx_minilist,N_minilist) Compute the standard Epstein-Nesbet perturbative first order coefficient and second order energetic contribution for the various N_st states. `c_pert(i)` = $\frac{\langle i|H|\alpha \rangle}{ E_n - \langle \alpha|H|\alpha \rangle }$. `e_2_pert(i)` = $\frac{\langle i|H|\alpha \rangle^2}{ E_n - \langle \alpha|H|\alpha \rangle }$. Needs: .. hlist:: :columns: 3 * :c:data:`mo_num` * :c:data:`n_det_selectors` * :c:data:`psi_selectors` * :c:data:`psi_selectors_size` * :c:data:`selection_criterion` Called by: .. hlist:: :columns: 3 * :c:func:`perturb_buffer_by_mono_epstein_nesbet` * :c:func:`perturb_buffer_epstein_nesbet` Calls: .. hlist:: :columns: 3 * :c:func:`i_h_psi_minilist` .. c:function:: pt2_epstein_nesbet_2x2: File : :file:`perturbation/pt2_equations.irp.f_template_305` .. code:: fortran subroutine pt2_epstein_nesbet_2x2 (electronic_energy,det_ref,det_pert,fock_diag_tmp,c_pert,e_2_pert,H_pert_diag,Nint,ndet,N_st,minilist,idx_minilist,N_minilist) Computes the Epstein-Nesbet 2x2 diagonalization coefficient and energetic contribution for the various N_st states. `e_2_pert(i)` = $\frac{1}{2} ( \langle \alpha|H|\alpha \rangle - E_n) - \sqrt{ (\langle \alpha|H|\alpha \rangle - E_n)^2 + 4 \langle i|H|\alpha \rangle^2 }$. `c_pert(i)` = `e_2_pert(i)` $\times \frac{1}{ \langle i|H|\alpha \rangle}$. Needs: .. hlist:: :columns: 3 * :c:data:`mo_num` * :c:data:`n_det_selectors` * :c:data:`psi_selectors` * :c:data:`psi_selectors_size` Called by: .. hlist:: :columns: 3 * :c:func:`perturb_buffer_by_mono_epstein_nesbet_2x2` * :c:func:`perturb_buffer_epstein_nesbet_2x2` Calls: .. hlist:: :columns: 3 * :c:func:`i_h_psi` .. c:function:: pt2_epstein_nesbet_2x2_no_ci_diag: File : :file:`perturbation/pt2_equations.irp.f_template_305` .. code:: fortran subroutine pt2_epstein_nesbet_2x2_no_ci_diag(electronic_energy,det_ref,det_pert,fock_diag_tmp,c_pert,e_2_pert,H_pert_diag,Nint,ndet,N_st,minilist,idx_minilist,N_minilist) compute the Epstein-Nesbet 2x2 diagonalization coefficient and energetic contribution for the various N_st states. e_2_pert(i) = 0.5 * (( - E(i) ) - sqrt( ( - E(i)) ^2 + 4 ^2 ) c_pert(i) = e_2_pert(i)/ Needs: .. hlist:: :columns: 3 * :c:data:`mo_num` * :c:data:`n_det_selectors` * :c:data:`psi_energy` * :c:data:`psi_selectors` * :c:data:`psi_selectors_size` Called by: .. hlist:: :columns: 3 * :c:func:`perturb_buffer_by_mono_epstein_nesbet_2x2_no_ci_diag` * :c:func:`perturb_buffer_epstein_nesbet_2x2_no_ci_diag` Calls: .. hlist:: :columns: 3 * :c:func:`i_h_psi` .. c:function:: pt2_moller_plesset: File : :file:`perturbation/pt2_equations.irp.f_template_305` .. code:: fortran subroutine pt2_moller_plesset (electronic_energy,det_ref,det_pert,fock_diag_tmp,c_pert,e_2_pert,H_pert_diag,Nint,ndet,N_st,minilist,idx_minilist,N_minilist) Computes the standard Moller-Plesset perturbative first order coefficient and second order energetic contribution for the various N_st states. `c_pert(i)` = $\frac{\langle i|H|\alpha \rangle}{\text{difference of orbital energies}}$. `e_2_pert(i)` = $\frac{\langle i|H|\alpha \rangle^2}{\text{difference of orbital energies}}$. Needs: .. hlist:: :columns: 3 * :c:data:`fock_matrix_mo` * :c:data:`mo_num` * :c:data:`n_det_selectors` * :c:data:`psi_selectors` * :c:data:`psi_selectors_size` * :c:data:`ref_bitmask` Called by: .. hlist:: :columns: 3 * :c:func:`perturb_buffer_by_mono_moller_plesset` * :c:func:`perturb_buffer_moller_plesset` Calls: .. hlist:: :columns: 3 * :c:func:`decode_exc` * :c:func:`get_excitation` * :c:func:`i_h_psi_minilist` .. c:function:: pt2_qdpt: File : :file:`perturbation/pt2_equations.irp.f_template_305` .. code:: fortran subroutine pt2_qdpt (electronic_energy,det_ref,det_pert,fock_diag_tmp,c_pert,e_2_pert,H_pert_diag,Nint,ndet,N_st,minilist,idx_minilist,N_minilist) Computes the QDPT first order coefficient and second order energetic contribution for the various N_st states. `c_pert(i)` = $\frac{\langle i|H|\alpha \rangle}{\langle i|H|i \rangle - \langle \alpha|H|\alpha \rangle}$. Needs: .. hlist:: :columns: 3 * :c:data:`mo_num` * :c:data:`n_det_selectors` * :c:data:`psi_selectors` * :c:data:`psi_selectors_size` * :c:data:`selection_criterion` Called by: .. hlist:: :columns: 3 * :c:func:`perturb_buffer_by_mono_qdpt` * :c:func:`perturb_buffer_qdpt` Calls: .. hlist:: :columns: 3 * :c:func:`get_excitation_degree` * :c:func:`i_h_j` * :c:func:`i_h_psi_minilist` .. c:function:: remove_small_contributions: File : :file:`perturbation/selection.irp.f` .. code:: fortran subroutine remove_small_contributions Remove determinants with small contributions. N_states is assumed to be provided. Needs: .. hlist:: :columns: 3 * :c:data:`n_det` * :c:data:`n_det_generators` * :c:data:`n_int` * :c:data:`n_states` * :c:data:`psi_coef` * :c:data:`psi_det_sorted` * :c:data:`psi_det` * :c:data:`psi_det_size` * :c:data:`psi_det_sorted` * :c:data:`selection_criterion` Calls: .. hlist:: :columns: 3 * :c:func:`diagonalize_ci` * :c:func:`i_h_psi` * :c:func:`write_int` Touches: .. hlist:: :columns: 3 * :c:data:`ci_electronic_energy` * :c:data:`ci_electronic_energy` * :c:data:`ci_energy` * :c:data:`ci_electronic_energy` * :c:data:`n_det` * :c:data:`psi_coef` * :c:data:`psi_det` * :c:data:`psi_energy` * :c:data:`psi_energy`