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:

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 \(\hat H\) matrix element of the perturber

Nint

Should be equal to N_int

Ndet

Number of determinants i in \(|\Psi \rangle\) on which we apply <det_pert | \(\hat H\) | i>

N_st

Number of states

EZFIO parameters

do_pt2

If True, compute the PT2 contribution

Default: True

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

pt2_relative_error

Stop stochastic PT2 when the relative error is smaller than PT2_relative_error

Default: 0.002

correlation_energy_ratio_max

The selection process stops at a fixed correlation ratio (useful for getting same accuracy between molecules).

Defined as \({E_{CI}-E_{HF}}/{E_{CI}+E_{PT2} - E_{HF}}\).

Default: 1.00

Providers

fill_h_apply_buffer_selection:()

File : perturbation/selection.irp.f

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:

selection_criterion h_apply_buffer_allocated

n_det

n_int

Calls:

omp_set_lock()

omp_unset_lock()

resize_h_apply_buffer()

h0_type

File : perturbation/h0_type.irp.f

character*32    :: h0_type

Type of zeroth-order Hamiltonian

Needs:

s2_eig

Needed by:

pt2_e0_denominator

max_exc_pert

File : perturbation/exc_max.irp.f

integer :: max_exc_pert

selection_criterion

File : perturbation/selection.irp.f

double precision        :: selection_criterion
double precision        :: selection_criterion_min
double precision        :: selection_criterion_factor

Threshold to select determinants. Set by selection routines.

selection_criterion_factor

File : perturbation/selection.irp.f

double precision        :: selection_criterion
double precision        :: selection_criterion_min
double precision        :: selection_criterion_factor

Threshold to select determinants. Set by selection routines.

selection_criterion_min

File : perturbation/selection.irp.f

double precision        :: selection_criterion
double precision        :: selection_criterion_min
double precision        :: selection_criterion_factor

Threshold to select determinants. Set by selection routines.

var_pt2_ratio

File : perturbation/var_pt2_ratio_provider.irp.f

double precision        :: var_pt2_ratio

The selection process stops when the energy ratio variational/(variational+PT2) is equal to var_pt2_ratio

Needs:

correlation_energy_ratio_max

Subroutines / functions

perturb_buffer_by_mono_dummy:()

File : perturbation/perturbation.irp.f_shell_13

   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)


Applly pertubration ``dummy`` to the buffer of determinants generated in the H_apply

routine.

Needs:

mo_num psi_selectors

n_det n_det_selectors

n_det_generators psi_det_generators

Calls:

create_minilist()

create_minilist_find_previous()

pt2_dummy()

perturb_buffer_by_mono_epstein_nesbet:()

File : perturbation/perturbation.irp.f_shell_13

   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)


Applly pertubration ``epstein_nesbet`` to the buffer of determinants generated in the H_apply

routine.

Needs:

mo_num psi_selectors

n_det n_det_selectors

n_det_generators psi_det_generators

Calls:

create_minilist()

create_minilist_find_previous()

pt2_epstein_nesbet()

perturb_buffer_by_mono_epstein_nesbet_2x2:()

File : perturbation/perturbation.irp.f_shell_13

   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)


Applly pertubration ``epstein_nesbet_2x2`` to the buffer of determinants generated in the H_apply

routine.

Needs:

mo_num psi_selectors

n_det n_det_selectors

n_det_generators psi_det_generators

Calls:

create_minilist()

create_minilist_find_previous()

pt2_epstein_nesbet_2x2()

perturb_buffer_by_mono_epstein_nesbet_2x2_no_ci_diag:()

File : perturbation/perturbation.irp.f_shell_13

   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)


Applly pertubration ``epstein_nesbet_2x2_no_ci_diag`` to the buffer of determinants generated in the H_apply

routine.

Needs:

mo_num psi_selectors

n_det n_det_selectors

n_det_generators psi_det_generators

Calls:

create_minilist()

create_minilist_find_previous()

pt2_epstein_nesbet_2x2_no_ci_diag()

perturb_buffer_by_mono_moller_plesset:()

File : perturbation/perturbation.irp.f_shell_13

   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)


Applly pertubration ``moller_plesset`` to the buffer of determinants generated in the H_apply

routine.

Needs:

mo_num psi_selectors

n_det n_det_selectors

n_det_generators psi_det_generators

Calls:

create_minilist()

create_minilist_find_previous()

pt2_moller_plesset()

perturb_buffer_by_mono_qdpt:()

File : perturbation/perturbation.irp.f_shell_13

   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)


Applly pertubration ``qdpt`` to the buffer of determinants generated in the H_apply

routine.

Needs:

mo_num psi_selectors

n_det n_det_selectors

n_det_generators psi_det_generators

Calls:

create_minilist()

create_minilist_find_previous()

pt2_qdpt()

perturb_buffer_dummy:()

File : perturbation/perturbation.irp.f_shell_13

   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)


Applly pertubration ``dummy`` to the buffer of determinants generated in the H_apply

routine.

Needs:

n_det_selectors n_det_generators

psi_selectors psi_det_generators

mo_num

Calls:

create_microlist() create_minilist()

create_minilist_find_previous() getmobiles()

pt2_dummy()

perturb_buffer_epstein_nesbet:()

File : perturbation/perturbation.irp.f_shell_13

   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)


Applly pertubration ``epstein_nesbet`` to the buffer of determinants generated in the H_apply

routine.

Needs:

n_det_selectors n_det_generators

psi_selectors psi_det_generators

mo_num

Calls:

create_microlist() create_minilist()

create_minilist_find_previous() getmobiles()

pt2_epstein_nesbet()

perturb_buffer_epstein_nesbet_2x2:()

File : perturbation/perturbation.irp.f_shell_13

   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)


Applly pertubration ``epstein_nesbet_2x2`` to the buffer of determinants generated in the H_apply

routine.

Needs:

n_det_selectors n_det_generators

psi_selectors psi_det_generators

mo_num

Calls:

create_microlist() create_minilist()

create_minilist_find_previous() getmobiles()

pt2_epstein_nesbet_2x2()

perturb_buffer_epstein_nesbet_2x2_no_ci_diag:()

File : perturbation/perturbation.irp.f_shell_13

   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)


Applly pertubration ``epstein_nesbet_2x2_no_ci_diag`` to the buffer of determinants generated in the H_apply

routine.

Needs:

n_det_selectors n_det_generators

psi_selectors psi_det_generators

mo_num

Calls:

create_microlist() create_minilist()

create_minilist_find_previous() getmobiles()

pt2_epstein_nesbet_2x2_no_ci_diag()

perturb_buffer_moller_plesset:()

File : perturbation/perturbation.irp.f_shell_13

   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)


Applly pertubration ``moller_plesset`` to the buffer of determinants generated in the H_apply

routine.

Needs:

n_det_selectors n_det_generators

psi_selectors psi_det_generators

mo_num

Calls:

create_microlist() create_minilist()

create_minilist_find_previous() getmobiles()

pt2_moller_plesset()

perturb_buffer_qdpt:()

File : perturbation/perturbation.irp.f_shell_13

   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)


Applly pertubration ``qdpt`` to the buffer of determinants generated in the H_apply

routine.

Needs:

n_det_selectors n_det_generators

psi_selectors psi_det_generators

mo_num

Calls:

create_microlist() create_minilist()

create_minilist_find_previous() getmobiles()

pt2_qdpt()

pt2_dummy:()

File : perturbation/pt2_equations.irp.f_template_305

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:

n_det_selectors selection_criterion

psi_selectors psi_selectors_size

mo_num

Called by:

perturb_buffer_by_mono_dummy()

perturb_buffer_dummy()

Calls:

i_h_psi_minilist()

pt2_epstein_nesbet:()

File : perturbation/pt2_equations.irp.f_template_305

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:

n_det_selectors selection_criterion

psi_selectors psi_selectors_size

mo_num

Called by:

perturb_buffer_by_mono_epstein_nesbet()

perturb_buffer_epstein_nesbet()

Calls:

i_h_psi_minilist()

pt2_epstein_nesbet_2x2:()

File : perturbation/pt2_equations.irp.f_template_305

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:

n_det_selectors psi_selectors

psi_selectors_size

mo_num

Called by:

perturb_buffer_by_mono_epstein_nesbet_2x2()

perturb_buffer_epstein_nesbet_2x2()

Calls:

i_h_psi()

pt2_epstein_nesbet_2x2_no_ci_diag:()

File : perturbation/pt2_equations.irp.f_template_305

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 * (( <det_pert|H|det_pert> - E(i) ) - sqrt( ( <det_pert|H|det_pert> - E(i)) ^2 + 4 <psi(i)|H|det_pert>^2 )

c_pert(i) = e_2_pert(i)/ <psi(i)|H|det_pert>

Needs:

n_det_selectors psi_selectors

psi_selectors_size psi_energy

mo_num

Called by:

perturb_buffer_by_mono_epstein_nesbet_2x2_no_ci_diag()

perturb_buffer_epstein_nesbet_2x2_no_ci_diag()

Calls:

i_h_psi()

pt2_moller_plesset:()

File : perturbation/pt2_equations.irp.f_template_305

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:

ref_bitmask psi_selectors_size

psi_selectors mo_num

n_det_selectors fock_matrix_mo

Called by:

perturb_buffer_by_mono_moller_plesset()

perturb_buffer_moller_plesset()

Calls:

decode_exc()

get_excitation()

i_h_psi_minilist()

pt2_qdpt:()

File : perturbation/pt2_equations.irp.f_template_305

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:

n_det_selectors selection_criterion

psi_selectors psi_selectors_size

mo_num

Called by:

perturb_buffer_by_mono_qdpt()

perturb_buffer_qdpt()

Calls:

get_excitation_degree()

i_h_j()

i_h_psi_minilist()

remove_small_contributions:()

File : perturbation/selection.irp.f

subroutine remove_small_contributions

Remove determinants with small contributions. N_states is assumed to be provided.

Needs:

psi_coef selection_criterion n_states n_det

psi_det_size n_det_generators n_int

psi_det_sorted psi_det psi_det_sorted

Calls:

diagonalize_ci()

i_h_psi()

write_int()

Touches:

ci_electronic_energy ci_electronic_energy ci_energy

ci_electronic_energy n_det

psi_coef psi_det