mirror of
https://github.com/QuantumPackage/qp2.git
synced 2024-08-30 20:53:42 +02:00
222 lines
6.3 KiB
Fortran
222 lines
6.3 KiB
Fortran
subroutine do_single_excitation(key_in,i_hole,i_particle,ispin,i_ok)
|
|
implicit none
|
|
BEGIN_DOC
|
|
! Apply the single excitation operator : a^{dager}_(i_particle) a_(i_hole) of spin = ispin
|
|
! on key_in
|
|
! ispin = 1 == alpha
|
|
! ispin = 2 == beta
|
|
! i_ok = 1 == the excitation is possible
|
|
! i_ok = -1 == the excitation is not possible
|
|
END_DOC
|
|
integer, intent(in) :: i_hole,i_particle,ispin
|
|
integer(bit_kind), intent(inout) :: key_in(N_int,2)
|
|
integer, intent(out) :: i_ok
|
|
integer :: k,j,i
|
|
integer(bit_kind) :: mask
|
|
use bitmasks
|
|
ASSERT (i_hole > 0 )
|
|
ASSERT (i_particle <= mo_num)
|
|
i_ok = 1
|
|
! hole
|
|
k = shiftr(i_hole-1,bit_kind_shift)+1
|
|
j = i_hole-shiftl(k-1,bit_kind_shift)-1
|
|
mask = ibset(0_bit_kind,j)
|
|
! check whether position j is occupied
|
|
if (iand(key_in(k,ispin),mask) /= 0_bit_kind) then
|
|
key_in(k,ispin) = ibclr(key_in(k,ispin),j)
|
|
else
|
|
i_ok= -1
|
|
return
|
|
end if
|
|
|
|
! particle
|
|
k = shiftr(i_particle-1,bit_kind_shift)+1
|
|
j = i_particle-shiftl(k-1,bit_kind_shift)-1
|
|
mask = ibset(0_bit_kind,j)
|
|
if (iand(key_in(k,ispin),mask) == 0_bit_kind) then
|
|
key_in(k,ispin) = ibset(key_in(k,ispin),j)
|
|
else
|
|
i_ok= -1
|
|
return
|
|
end if
|
|
|
|
! integer :: n_elec_tmp
|
|
! n_elec_tmp = 0
|
|
! do i = 1, N_int
|
|
! n_elec_tmp += popcnt(key_in(i,1)) + popcnt(key_in(i,2))
|
|
! enddo
|
|
! if(n_elec_tmp .ne. elec_num)then
|
|
! print*, n_elec_tmp,elec_num
|
|
! call debug_det(key_in,N_int)
|
|
! stop -1
|
|
! endif
|
|
end
|
|
|
|
|
|
subroutine build_singly_excited_wavefunction(i_hole,i_particle,ispin,det_out,coef_out)
|
|
implicit none
|
|
BEGIN_DOC
|
|
! Applies the single excitation operator : a^{dager}_(i_particle) a_(i_hole) of
|
|
! spin = ispin to the current wave function (psi_det, psi_coef)
|
|
END_DOC
|
|
integer, intent(in) :: i_hole,i_particle,ispin
|
|
integer(bit_kind), intent(out) :: det_out(N_int,2,N_det)
|
|
double precision, intent(out) :: coef_out(N_det,N_states)
|
|
|
|
integer :: k
|
|
integer :: i_ok
|
|
double precision :: phase
|
|
do k=1,N_det
|
|
coef_out(k,:) = psi_coef(k,:)
|
|
det_out(:,:,k) = psi_det(:,:,k)
|
|
call do_single_excitation(det_out(1,1,k),i_hole,i_particle,ispin,i_ok)
|
|
if (i_ok == 1) then
|
|
call get_phase(psi_det(1,1,k), det_out(1,1,k),phase,N_int)
|
|
coef_out(k,:) = phase * coef_out(k,:)
|
|
else
|
|
coef_out(k,:) = 0.d0
|
|
det_out(:,:,k) = psi_det(:,:,k)
|
|
endif
|
|
enddo
|
|
end
|
|
|
|
logical function is_spin_flip_possible(key_in,i_flip,ispin)
|
|
implicit none
|
|
BEGIN_DOC
|
|
! returns |true| if the spin-flip of spin ispin in the orbital i_flip is possible
|
|
! on key_in
|
|
END_DOC
|
|
integer, intent(in) :: i_flip,ispin
|
|
integer(bit_kind), intent(in) :: key_in(N_int,2)
|
|
integer :: k,j,i
|
|
integer(bit_kind) :: key_tmp(N_int,2)
|
|
is_spin_flip_possible = .False.
|
|
key_tmp = 0_bit_kind
|
|
k = shiftr(i_flip-1,bit_kind_shift)+1
|
|
j = i_flip-shiftl(k-1,bit_kind_shift)-1
|
|
key_tmp(k,1) = ibset(key_tmp(k,1),j)
|
|
integer :: other_spin(2)
|
|
other_spin(1) = 2
|
|
other_spin(2) = 1
|
|
if(popcnt(iand(key_tmp(k,1),key_in(k,ispin))) == 1 .and. popcnt(iand(key_tmp(k,1),key_in(k,other_spin(ispin)))) == 0 )then
|
|
! There is a spin "ispin" in the orbital i_flip AND There is no electron of opposit spin in the same orbital "i_flip"
|
|
is_spin_flip_possible = .True.
|
|
return
|
|
else
|
|
return
|
|
endif
|
|
end
|
|
|
|
subroutine do_single_excitation_cfg(key_in,key_out,i_hole,i_particle,ok)
|
|
use bitmasks
|
|
implicit none
|
|
BEGIN_DOC
|
|
! Applies the signle excitation operator to a configuration
|
|
! If the excitation is possible, ok is True
|
|
END_DOC
|
|
integer, intent(in) :: i_hole,i_particle
|
|
integer(bit_kind), intent(in) :: key_in(N_int,2)
|
|
logical , intent(out) :: ok
|
|
integer :: k,j,i
|
|
integer(bit_kind) :: mask
|
|
integer(bit_kind) :: key_out(N_int,2)
|
|
|
|
ASSERT (i_hole > 0)
|
|
ASSERT (i_particle <= mo_num)
|
|
|
|
ok = .True.
|
|
key_out(:,:) = key_in(:,:)
|
|
|
|
! hole
|
|
k = shiftr(i_hole-1,bit_kind_shift)+1
|
|
j = i_hole-shiftl(k-1,bit_kind_shift)-1
|
|
mask = ibset(0_bit_kind,j)
|
|
|
|
! Check if the position j is singly occupied
|
|
! 1 -> 0 (SOMO)
|
|
! 0 0 (DOMO)
|
|
if (iand(key_out(k,1),mask) /= 0_bit_kind) then
|
|
key_out(k,1) = ibclr(key_out(k,1),j)
|
|
|
|
! Check if the position j is doubly occupied
|
|
! 0 -> 1 (SOMO)
|
|
! 1 0 (DOMO)
|
|
else if (iand(key_out(k,2),mask) /= 0_bit_kind) then
|
|
key_out(k,1) = ibset(key_out(k,1),j)
|
|
key_out(k,2) = ibclr(key_out(k,2),j)
|
|
|
|
! The position j is unoccupied: Not OK
|
|
! 0 -> 0 (SOMO)
|
|
! 0 0 (DOMO)
|
|
else
|
|
ok =.False.
|
|
return
|
|
endif
|
|
|
|
|
|
! particle
|
|
k = shiftr(i_particle-1,bit_kind_shift)+1
|
|
j = i_particle-shiftl(k-1,bit_kind_shift)-1
|
|
mask = ibset(0_bit_kind,j)
|
|
|
|
! Check if the position j is singly occupied
|
|
! 1 -> 0 (SOMO)
|
|
! 0 1 (DOMO)
|
|
if (iand(key_out(k,1),mask) /= 0_bit_kind) then
|
|
key_out(k,1) = ibclr(key_out(k,1),j)
|
|
key_out(k,2) = ibset(key_out(k,2),j)
|
|
|
|
! Check if the position j is doubly occupied : Not OK
|
|
! 0 -> 1 (SOMO)
|
|
! 1 0 (DOMO)
|
|
else if (iand(key_out(k,2),mask) /= 0_bit_kind) then
|
|
ok = .False.
|
|
return
|
|
|
|
! Position at j is unoccupied
|
|
! 0 -> 0 (SOMO)
|
|
! 0 0 (DOMO)
|
|
else
|
|
key_out(k,1) = ibset(key_out(k,1),j)
|
|
endif
|
|
|
|
end
|
|
|
|
subroutine generate_all_singles_cfg(cfg,singles,n_singles,Nint)
|
|
implicit none
|
|
use bitmasks
|
|
BEGIN_DOC
|
|
! Generate all single excitation wrt a configuration
|
|
!
|
|
! n_singles : on input, max number of singles :
|
|
! elec_alpha_num * (mo_num - elec_beta_num)
|
|
! on output, number of generated singles
|
|
END_DOC
|
|
integer, intent(in) :: Nint
|
|
integer, intent(inout) :: n_singles
|
|
integer(bit_kind), intent(in) :: cfg(Nint,2)
|
|
integer(bit_kind), intent(out) :: singles(Nint,2,*)
|
|
|
|
integer :: i,k, n_singles_ma, i_hole, i_particle
|
|
integer(bit_kind) :: single(Nint,2)
|
|
logical :: i_ok
|
|
|
|
n_singles = 0
|
|
!TODO
|
|
!Make list of Somo and Domo for holes
|
|
!Make list of Unocc and Somo for particles
|
|
do i_hole = 1, mo_num
|
|
do i_particle = 1, mo_num
|
|
call do_single_excitation_cfg(cfg,single,i_hole,i_particle,i_ok)
|
|
if (i_ok) then
|
|
n_singles = n_singles + 1
|
|
do k=1,Nint
|
|
singles(k,1,n_singles) = single(k,1)
|
|
singles(k,2,n_singles) = single(k,2)
|
|
enddo
|
|
endif
|
|
enddo
|
|
enddo
|
|
end
|
|
|