mirror of
https://github.com/QuantumPackage/qp2.git
synced 2024-07-06 19:36:09 +02:00
133 lines
4.1 KiB
Fortran
133 lines
4.1 KiB
Fortran
|
BEGIN_PROVIDER [ double precision, tc_two_rdm, (mo_num, mo_num, mo_num, mo_num)]
|
||
|
|
implicit none
|
||
|
|
BEGIN_DOC
|
||
|
|
! tc_two_rdm(p,s,q,r) = <Phi| a^dager_p
|
||
|
|
END_DOC
|
||
|
|
integer :: i,j,istate,m,mm,nn
|
||
|
|
integer :: exc(0:2,2,2)
|
||
|
|
double precision :: phase
|
||
|
|
double precision :: contrib
|
||
|
|
integer :: h1,p1,s1,h2,p2,s2,degree
|
||
|
|
integer, allocatable :: occ(:,:)
|
||
|
|
integer :: n_occ_ab(2),other_spin(2)
|
||
|
|
other_spin(1) = 2
|
||
|
|
other_spin(2) = 1
|
||
|
|
allocate(occ(N_int*bit_kind_size,2))
|
||
|
|
tc_two_rdm = 0.d0
|
||
|
|
|
||
|
|
do i = 1, N_det ! psi_left
|
||
|
|
do j = 1, N_det ! psi_right
|
||
|
|
call get_excitation_degree(psi_det(1,1,i),psi_det(1,1,j),degree,N_int)
|
||
|
|
if(degree.gt.2)cycle
|
||
|
|
if(degree.gt.0)then
|
||
|
|
! get excitation operators: from psi_det(j) --> psi_det(i)
|
||
|
|
call get_excitation(psi_det(1,1,j),psi_det(1,1,i),exc,degree,phase,N_int)
|
||
|
|
call decode_exc(exc,degree,h1,p1,h2,p2,s1,s2)
|
||
|
|
contrib = psi_l_coef_bi_ortho(i,1) * psi_r_coef_bi_ortho(j,1) * phase * state_average_weight(1)
|
||
|
|
do istate = 2, N_states
|
||
|
|
contrib += psi_l_coef_bi_ortho(i,istate) * psi_r_coef_bi_ortho(j,istate) * phase * state_average_weight(istate)
|
||
|
|
enddo
|
||
|
|
if(degree == 2)then
|
||
|
|
call update_tc_rdm(h1,p1,h2,p2,s1,s2,tc_two_rdm,mo_num,contrib)
|
||
|
|
else if(degree==1)then
|
||
|
|
! cycle
|
||
|
|
! occupation of the determinant psi_det(j)
|
||
|
|
call bitstring_to_list_ab(psi_det(1,1,j), occ, n_occ_ab, N_int)
|
||
|
|
|
||
|
|
! run over the electrons of opposite spin than the excitation
|
||
|
|
s2 = other_spin(s1)
|
||
|
|
do mm = 1, n_occ_ab(s2)
|
||
|
|
m = occ(mm,s2)
|
||
|
|
h2 = m
|
||
|
|
p2 = m
|
||
|
|
call update_tc_rdm(h1,p1,h2,p2,s1,s2,tc_two_rdm,mo_num,contrib)
|
||
|
|
enddo
|
||
|
|
! run over the electrons of same spin than the excitation
|
||
|
|
s2 = s1
|
||
|
|
do mm = 1, n_occ_ab(s2)
|
||
|
|
m = occ(mm,s2)
|
||
|
|
h2 = m
|
||
|
|
p2 = m
|
||
|
|
if(h2.le.h1)cycle
|
||
|
|
call update_tc_rdm(h1,p1,h2,p2,s1,s2,tc_two_rdm,mo_num,contrib)
|
||
|
|
enddo
|
||
|
|
endif
|
||
|
|
else if(degree == 0)then
|
||
|
|
contrib = psi_l_coef_bi_ortho(i,1) * psi_r_coef_bi_ortho(j,1) * state_average_weight(1)
|
||
|
|
! print*,'contrib',contrib
|
||
|
|
do istate = 2, N_states
|
||
|
|
contrib += psi_l_coef_bi_ortho(i,istate) * psi_r_coef_bi_ortho(j,istate) * state_average_weight(istate)
|
||
|
|
enddo
|
||
|
|
! occupation of the determinant psi_det(j)
|
||
|
|
call bitstring_to_list_ab(psi_det(1,1,j), occ, n_occ_ab, N_int)
|
||
|
|
s1 = 1 ! alpha electrons
|
||
|
|
do nn = 1, n_occ_ab(s1)
|
||
|
|
h1 = occ(nn,s1)
|
||
|
|
p1 = occ(nn,s1)
|
||
|
|
! run over the couple of alpha-beta electrons
|
||
|
|
s2 = other_spin(s1)
|
||
|
|
do mm = 1, n_occ_ab(s2)
|
||
|
|
m = occ(mm,s2)
|
||
|
|
h2 = m
|
||
|
|
p2 = m
|
||
|
|
call update_tc_rdm(h1,p1,h2,p2,s1,s2,tc_two_rdm,mo_num,contrib)
|
||
|
|
enddo
|
||
|
|
! run over the couple of alpha-alpha electrons
|
||
|
|
s2 = s1
|
||
|
|
do mm = 1, n_occ_ab(s2)
|
||
|
|
m = occ(mm,s2)
|
||
|
|
h2 = m
|
||
|
|
p2 = m
|
||
|
|
if(h2.le.h1)cycle
|
||
|
|
call update_tc_rdm(h1,p1,h2,p2,s1,s2,tc_two_rdm,mo_num,contrib)
|
||
|
|
enddo
|
||
|
|
enddo
|
||
|
|
s1 = 2
|
||
|
|
do nn = 1, n_occ_ab(s1)
|
||
|
|
h1 = occ(nn,s1)
|
||
|
|
p1 = occ(nn,s1)
|
||
|
|
! run over the couple of beta-beta electrons
|
||
|
|
s2 = s1
|
||
|
|
do mm = 1, n_occ_ab(s2)
|
||
|
|
m = occ(mm,s2)
|
||
|
|
h2 = m
|
||
|
|
p2 = m
|
||
|
|
if(h2.le.h1)cycle
|
||
|
|
call update_tc_rdm(h1,p1,h2,p2,s1,s2,tc_two_rdm,mo_num,contrib)
|
||
|
|
enddo
|
||
|
|
enddo
|
||
|
|
endif
|
||
|
|
enddo
|
||
|
|
enddo
|
||
|
|
|
||
|
|
END_PROVIDER
|
||
|
|
|
||
|
|
subroutine update_tc_rdm(h1,p1,h2,p2,s1,s2,array,sze,contrib)
|
||
|
|
implicit none
|
||
|
|
integer, intent(in) :: h1,p1,h2,p2,s1,s2,sze
|
||
|
|
double precision, intent(in) :: contrib
|
||
|
|
double precision, intent(inout) :: array(sze, sze, sze, sze)
|
||
|
|
integer :: istate
|
||
|
|
if(s1.ne.s2)then
|
||
|
|
array(p1,h1,p2,h2) += contrib
|
||
|
|
! permutation for particle symmetry
|
||
|
|
array(p2,h2,p1,h1) += contrib
|
||
|
|
else ! same spin double excitation
|
||
|
|
array(p1,h1,p2,h2) += contrib
|
||
|
|
! exchange
|
||
|
|
! exchanging the holes
|
||
|
|
array(p2,h1,p1,h2) -= contrib
|
||
|
|
! exchanging the particles
|
||
|
|
array(p1,h2,p2,h1) -= contrib
|
||
|
|
|
||
|
|
! permutation for particle symmetry
|
||
|
|
array(p2,h2,p1,h1) += contrib
|
||
|
|
! exchange
|
||
|
|
! exchanging the holes
|
||
|
|
array(p1,h2,p2,h1) -= contrib
|
||
|
|
! exchanging the particles
|
||
|
|
array(p2,h1,p1,h2) -= contrib
|
||
|
|
endif
|
||
|
|
|
||
|
|
end
|