subroutine pt2_epstein_nesbet_SC2_projected(det_pert,c_pert,e_2_pert,H_pert_diag,Nint,ndet,N_st) use bitmasks implicit none integer, intent(in) :: Nint,ndet,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(N_st) double precision :: i_H_psi_array(N_st) integer :: idx_repeat(0:ndet) BEGIN_DOC ! compute the Epstein-Nesbet perturbative first order coefficient and second order energetic contribution ! ! for the various N_st states, ! ! but with the correction in the denominator ! ! comming from the interaction of that determinant with all the others determinants ! ! that can be repeated by repeating all the double excitations ! ! : you repeat all the correlation energy already taken into account in CI_electronic_energy(1) ! ! that could be repeated to this determinant. ! ! In addition, for the perturbative energetic contribution you have the standard second order ! ! e_2_pert = ^2/(Delta_E) ! ! and also the purely projected contribution ! ! H_pert_diag = c_pert END_DOC integer :: i,j,degree,l double precision :: diag_H_mat_elem,accu_e_corr,hij,h0j,h,delta_E double precision :: repeat_all_e_corr,accu_e_corr_tmp,e_2_pert_fonda ASSERT (Nint == N_int) ASSERT (Nint > 0) call i_H_psi_SC2(det_pert,psi_selectors,psi_selectors_coef,Nint,N_det_selectors,psi_selectors_size,N_st,i_H_psi_array,idx_repeat) accu_e_corr = 0.d0 !$IVDEP do i = 1, idx_repeat(0) accu_e_corr = accu_e_corr + E_corr_per_selectors(idx_repeat(i)) enddo h = diag_H_mat_elem(det_pert,Nint) + accu_e_corr delta_E = 1.d0/(CI_SC2_electronic_energy(1) - h) c_pert(1) = i_H_psi_array(1) /(CI_SC2_electronic_energy(1) - h) e_2_pert(1) = i_H_psi_array(1) * c_pert(1) do i =2,N_st H_pert_diag(i) = h if (dabs(CI_SC2_electronic_energy(i) - h) > 1.d-6) then c_pert(i) = i_H_psi_array(i) / (-dabs(CI_SC2_electronic_energy(i) - h)) e_2_pert(i) = (c_pert(i) * i_H_psi_array(i)) else c_pert(i) = i_H_psi_array(i) e_2_pert(i) = -dabs(i_H_psi_array(i)) endif enddo degree = popcnt(xor( ref_bitmask(1,1), det_pert(1,1))) + & popcnt(xor( ref_bitmask(1,2), det_pert(1,2))) !DEC$ NOUNROLL do l=2,Nint degree = degree+ popcnt(xor( ref_bitmask(l,1), det_pert(l,1))) + & popcnt(xor( ref_bitmask(l,2), det_pert(l,2))) enddo if(degree==4)then ! e_2_pert_fonda = e_2_pert(1) H_pert_diag(1) = e_2_pert(1) * c_pert(1) * c_pert(1) do i = 1, N_st do j = 1, idx_repeat(0) e_2_pert(i) += e_2_pert_fonda * psi_selectors_coef(idx_repeat(j),i) * psi_selectors_coef(idx_repeat(j),i) enddo enddo endif end subroutine pt2_epstein_nesbet_SC2_no_projected(det_pert,c_pert,e_2_pert,H_pert_diag,Nint,ndet,N_st) use bitmasks implicit none integer, intent(in) :: Nint,ndet,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(N_st) double precision :: i_H_psi_array(N_st) integer :: idx_repeat(0:ndet) BEGIN_DOC ! compute the Epstein-Nesbet perturbative first order coefficient and second order energetic contribution ! ! for the various N_st states, ! ! but with the correction in the denominator ! ! comming from the interaction of that determinant with all the others determinants ! ! that can be repeated by repeating all the double excitations ! ! : you repeat all the correlation energy already taken into account in CI_electronic_energy(1) ! ! that could be repeated to this determinant. ! ! In addition, for the perturbative energetic contribution you have the standard second order ! ! e_2_pert = ^2/(Delta_E) ! ! and also the purely projected contribution ! ! H_pert_diag = c_pert END_DOC integer :: i,j,degree,l double precision :: diag_H_mat_elem,accu_e_corr,hij,h0j,h,delta_E double precision :: repeat_all_e_corr,accu_e_corr_tmp,e_2_pert_fonda ASSERT (Nint == N_int) ASSERT (Nint > 0) call i_H_psi_SC2(det_pert,psi_selectors,psi_selectors_coef,Nint,N_det_selectors,psi_selectors_size,N_st,i_H_psi_array,idx_repeat) accu_e_corr = 0.d0 !$IVDEP do i = 1, idx_repeat(0) accu_e_corr = accu_e_corr + E_corr_per_selectors(idx_repeat(i)) enddo h = diag_H_mat_elem(det_pert,Nint) + accu_e_corr delta_E = 1.d0/(CI_SC2_electronic_energy(1) - h) c_pert(1) = i_H_psi_array(1) /(CI_SC2_electronic_energy(1) - h) e_2_pert(1) = i_H_psi_array(1) * c_pert(1) do i =2,N_st H_pert_diag(i) = h if (dabs(CI_SC2_electronic_energy(i) - h) > 1.d-6) then c_pert(i) = i_H_psi_array(i) / (-dabs(CI_SC2_electronic_energy(i) - h)) e_2_pert(i) = (c_pert(i) * i_H_psi_array(i)) else c_pert(i) = i_H_psi_array(i) e_2_pert(i) = -dabs(i_H_psi_array(i)) endif enddo end double precision function repeat_all_e_corr(key_in) implicit none integer(bit_kind), intent(in) :: key_in(N_int,2) integer :: i,degree double precision :: accu use bitmasks accu = 0.d0 call get_excitation_degree(key_in,ref_bitmask,degree,N_int) if(degree==2)then do i = 1, N_det_selectors call get_excitation_degree(ref_bitmask,psi_selectors(1,1,i),degree,N_int) if(degree.ne.2)cycle call get_excitation_degree(key_in,psi_selectors(1,1,i),degree,N_int) if (degree<=3)cycle accu += E_corr_per_selectors(i) enddo elseif(degree==1)then do i = 1, N_det_selectors call get_excitation_degree(ref_bitmask,psi_selectors(1,1,i),degree,N_int) if(degree.ne.2)cycle call get_excitation_degree(key_in,psi_selectors(1,1,i),degree,N_int) if (degree<=2)cycle accu += E_corr_per_selectors(i) enddo endif repeat_all_e_corr = accu end subroutine pt2_epstein_nesbet_sc2(det_pert,c_pert,e_2_pert,H_pert_diag,Nint,ndet,N_st) use bitmasks implicit none integer, intent(in) :: Nint,ndet,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(N_st) double precision :: i_H_psi_array(N_st) BEGIN_DOC ! compute the standard Epstein-Nesbet perturbative first order coefficient and second order energetic contribution ! ! for the various N_st states, but with the CISD_SC2 energies and coefficients ! ! c_pert(i) = /( E(i) - ) ! ! e_2_pert(i) = ^2/( E(i) - ) ! END_DOC integer :: i,j double precision :: diag_H_mat_elem, h PROVIDE selection_criterion ASSERT (Nint == N_int) ASSERT (Nint > 0) call i_H_psi(det_pert,psi_selectors,psi_selectors_coef,Nint,N_det_selectors,psi_selectors_size,N_st,i_H_psi_array) h = diag_H_mat_elem(det_pert,Nint) do i =1,N_st if(CI_SC2_electronic_energy(i)>h.and.CI_SC2_electronic_energy(i).ne.0.d0)then c_pert(i) = -1.d0 e_2_pert(i) = selection_criterion*selection_criterion_factor*2.d0 else if (dabs(CI_SC2_electronic_energy(i) - h) > 1.d-6) then c_pert(i) = i_H_psi_array(i) / (CI_SC2_electronic_energy(i) - h) H_pert_diag(i) = h*c_pert(i)*c_pert(i) e_2_pert(i) = c_pert(i) * i_H_psi_array(i) else c_pert(i) = -1.d0 e_2_pert(i) = -dabs(i_H_psi_array(i)) H_pert_diag(i) = h endif enddo end