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mirror of https://github.com/QuantumPackage/qp2.git synced 2024-07-23 02:57:24 +02:00
qp2/src/determinants/s2.irp.f

402 lines
11 KiB
Fortran

double precision function diag_S_mat_elem(key_i,Nint)
implicit none
use bitmasks
include 'utils/constants.include.F'
integer :: Nint
integer(bit_kind), intent(in) :: key_i(Nint,2)
BEGIN_DOC
! Returns <i|S^2|i>
END_DOC
integer :: nup, ntot, i
integer(bit_kind) :: xorvec(N_int_max), upvec(N_int_max)
do i=1,Nint
xorvec(i) = xor(key_i(i,1),key_i(i,2))
enddo
do i=1,Nint
upvec(i) = iand(xorvec(i),key_i(i,1))
enddo
! nup is number of alpha unpaired
! ntot is total number of unpaired
nup = 0
ntot = 0
do i=1,Nint
if (xorvec(i) /= 0_bit_kind) then
ntot += popcnt(xorvec(i))
if (upvec(i) /= 0_bit_kind) then
nup += popcnt(upvec(i))
endif
endif
enddo
double precision :: sz
sz = nup - 0.5d0*ntot
!<S^2> = <S+ S-> + Sz(Sz-1)
diag_S_mat_elem = nup + sz*(sz-1)
end
subroutine get_s2(key_i,key_j,Nint,s2)
implicit none
use bitmasks
BEGIN_DOC
! Returns $\langle S^2 \rangle - S_z^2 S_z$
END_DOC
integer, intent(in) :: Nint
integer(bit_kind), intent(in) :: key_i(Nint,2)
integer(bit_kind), intent(in) :: key_j(Nint,2)
double precision, intent(out) :: s2
integer :: exc(0:2,2,2)
integer :: degree
double precision :: phase_spsm
integer :: nup, i
s2 = 0.d0
!$FORCEINLINE
call get_excitation_degree(key_i,key_j,degree,Nint)
select case (degree)
case(2)
call get_double_excitation(key_j,key_i,exc,phase_spsm,Nint)
if (exc(0,1,1) == 1) then ! Mono alpha + mono-beta
if ( (exc(1,1,1) == exc(1,2,2)).and.(exc(1,1,2) == exc(1,2,1)) ) then
s2 = -phase_spsm
endif
endif
case(0)
double precision, external :: diag_S_mat_elem
!DIR$ FORCEINLINE
s2 = diag_S_mat_elem(key_i,Nint)
end select
end
BEGIN_PROVIDER [ double precision, S_z ]
&BEGIN_PROVIDER [ double precision, S_z2_Sz ]
implicit none
BEGIN_DOC
! z component of the Spin
END_DOC
S_z = 0.5d0*dble(elec_alpha_num-elec_beta_num)
S_z2_Sz = S_z*(S_z-1.d0)
END_PROVIDER
BEGIN_PROVIDER [ double precision, expected_s2]
implicit none
BEGIN_DOC
! Expected value of |S^2| : S*(S+1)
END_DOC
logical :: has_expected_s2
call ezfio_has_determinants_expected_s2(has_expected_s2)
if (has_expected_s2) then
call ezfio_get_determinants_expected_s2(expected_s2)
else
double precision :: S
S = (elec_alpha_num-elec_beta_num)*0.5d0
expected_s2 = S * (S+1.d0)
endif
END_PROVIDER
BEGIN_PROVIDER [ double precision, s2_values, (N_states) ]
&BEGIN_PROVIDER [ double precision, s_values, (N_states) ]
implicit none
BEGIN_DOC
! array of the averaged values of the S^2 operator on the various states
END_DOC
integer :: i
call u_0_S2_u_0(s2_values,psi_coef,n_det,psi_det,N_int,N_states,psi_det_size)
do i = 1, N_states
s_values(i) = 0.5d0 *(-1.d0 + dsqrt(1.d0 + 4 * s2_values(i)))
enddo
END_PROVIDER
subroutine u_0_S2_u_0(e_0,u_0,n,keys_tmp,Nint,N_st,sze_8)
use bitmasks
implicit none
BEGIN_DOC
! Computes e_0 = <u_0|S2|u_0>/<u_0|u_0>
!
! n : number of determinants
!
END_DOC
integer, intent(in) :: n,Nint, N_st, sze_8
double precision, intent(out) :: e_0(N_st)
double precision, intent(in) :: u_0(sze_8,N_st)
integer(bit_kind),intent(in) :: keys_tmp(Nint,2,n)
double precision, allocatable :: v_0(:,:)
double precision :: u_dot_u,u_dot_v
integer :: i,j
allocate (v_0(sze_8,N_st))
call S2_u_0_nstates(v_0,u_0,n,keys_tmp,Nint,N_st,sze_8)
do i=1,N_st
e_0(i) = u_dot_v(v_0(1,i),u_0(1,i),n)/u_dot_u(u_0(1,i),n)
enddo
end
subroutine S2_u_0(v_0,u_0,n,keys_tmp,Nint)
use bitmasks
implicit none
BEGIN_DOC
! Computes v_0 = S^2|u_0>
!
! n : number of determinants
!
END_DOC
integer, intent(in) :: n,Nint
double precision, intent(out) :: v_0(n)
double precision, intent(in) :: u_0(n)
integer(bit_kind),intent(in) :: keys_tmp(Nint,2,n)
call S2_u_0_nstates(v_0,u_0,n,keys_tmp,Nint,1,n)
end
subroutine S2_u_0_nstates(v_0,u_0,n,keys_tmp,Nint,N_st,sze_8)
use bitmasks
implicit none
BEGIN_DOC
! Computes v_0 = S^2|u_0>
!
! n : number of determinants
!
END_DOC
integer, intent(in) :: N_st,n,Nint, sze_8
double precision, intent(out) :: v_0(sze_8,N_st)
double precision, intent(in) :: u_0(sze_8,N_st)
integer(bit_kind),intent(in) :: keys_tmp(Nint,2,n)
double precision :: s2_tmp
double precision, allocatable :: vt(:,:)
integer :: i,j,k,l, jj,ii
integer :: i0, j0
integer, allocatable :: shortcut(:,:), sort_idx(:,:)
integer(bit_kind), allocatable :: sorted(:,:,:), version(:,:,:)
integer(bit_kind) :: sorted_i(Nint)
integer :: sh, sh2, ni, exa, ext, org_i, org_j, endi, istate
ASSERT (Nint > 0)
ASSERT (Nint == N_int)
ASSERT (n>0)
PROVIDE ref_bitmask_energy
allocate (shortcut(0:n+1,2), sort_idx(n,2), sorted(Nint,n,2), version(Nint,n,2))
v_0 = 0.d0
call sort_dets_ab_v(keys_tmp, sorted(1,1,1), sort_idx(1,1), shortcut(0,1), version(1,1,1), n, Nint)
call sort_dets_ba_v(keys_tmp, sorted(1,1,2), sort_idx(1,2), shortcut(0,2), version(1,1,2), n, Nint)
!$OMP PARALLEL DEFAULT(NONE) &
!$OMP PRIVATE(i,s2_tmp,j,k,jj,vt,ii,sh,sh2,ni,exa,ext,org_i,org_j,endi,sorted_i,istate)&
!$OMP SHARED(n,u_0,keys_tmp,Nint,v_0,sorted,shortcut,sort_idx,version,N_st,sze_8)
allocate(vt(sze_8,N_st))
vt = 0.d0
do sh=1,shortcut(0,1)
!$OMP DO SCHEDULE(static,1)
do sh2=sh,shortcut(0,1)
exa = 0
do ni=1,Nint
exa = exa + popcnt(xor(version(ni,sh,1), version(ni,sh2,1)))
end do
if(exa > 2) then
cycle
end if
do i=shortcut(sh,1),shortcut(sh+1,1)-1
org_i = sort_idx(i,1)
if(sh==sh2) then
endi = i-1
else
endi = shortcut(sh2+1,1)-1
end if
do ni=1,Nint
sorted_i(ni) = sorted(ni,i,1)
enddo
do j=shortcut(sh2,1),endi
org_j = sort_idx(j,1)
ext = exa
do ni=1,Nint
ext = ext + popcnt(xor(sorted_i(ni), sorted(ni,j,1)))
end do
if(ext <= 4) then
call get_s2(keys_tmp(1,1,org_i),keys_tmp(1,1,org_j),Nint,s2_tmp)
do istate=1,N_st
vt (org_i,istate) = vt (org_i,istate) + s2_tmp*u_0(org_j,istate)
vt (org_j,istate) = vt (org_j,istate) + s2_tmp*u_0(org_i,istate)
enddo
endif
enddo
enddo
enddo
!$OMP END DO NOWAIT
enddo
do sh=1,shortcut(0,2)
!$OMP DO
do i=shortcut(sh,2),shortcut(sh+1,2)-1
org_i = sort_idx(i,2)
do j=shortcut(sh,2),i-1
org_j = sort_idx(j,2)
ext = 0
do ni=1,Nint
ext = ext + popcnt(xor(sorted(ni,i,2), sorted(ni,j,2)))
end do
if(ext == 4) then
call get_s2(keys_tmp(1,1,org_i),keys_tmp(1,1,org_j),Nint,s2_tmp)
do istate=1,N_st
vt (org_i,istate) = vt (org_i,istate) + s2_tmp*u_0(org_j,istate)
vt (org_j,istate) = vt (org_j,istate) + s2_tmp*u_0(org_i,istate)
enddo
end if
end do
end do
!$OMP END DO NOWAIT
enddo
!$OMP BARRIER
do istate=1,N_st
do i=n,1,-1
!$OMP ATOMIC
v_0(i,istate) = v_0(i,istate) + vt(i,istate)
enddo
enddo
deallocate(vt)
!$OMP END PARALLEL
do i=1,n
call get_s2(keys_tmp(1,1,i),keys_tmp(1,1,i),Nint,s2_tmp)
do istate=1,N_st
v_0(i,istate) += s2_tmp * u_0(i,istate)
enddo
enddo
deallocate (shortcut, sort_idx, sorted, version)
end
subroutine get_uJ_s2_uI(psi_keys_tmp,psi_coefs_tmp,n,nmax_coefs,nmax_keys,s2,nstates)
implicit none
use bitmasks
integer, intent(in) :: n,nmax_coefs,nmax_keys,nstates
integer(bit_kind), intent(in) :: psi_keys_tmp(N_int,2,nmax_keys)
double precision, intent(in) :: psi_coefs_tmp(nmax_coefs,nstates)
double precision, intent(out) :: s2(nstates,nstates)
double precision :: s2_tmp,accu
integer :: i,j,l,jj,ll,kk
integer, allocatable :: idx(:)
BEGIN_DOC
! returns the matrix elements of S^2 "s2(i,j)" between the "nstates" states
! psi_coefs_tmp(:,i) and psi_coefs_tmp(:,j)
END_DOC
s2 = 0.d0
do ll = 1, nstates
do jj = 1, nstates
accu = 0.d0
!$OMP PARALLEL DEFAULT(NONE) &
!$OMP PRIVATE (i,j,kk,idx,s2_tmp) &
!$OMP SHARED (ll,jj,psi_keys_tmp,psi_coefs_tmp,N_int,n,nstates)&
!$OMP REDUCTION(+:accu)
allocate(idx(0:n))
!$OMP DO SCHEDULE(guided)
do i = n,1,-1 ! Better OMP scheduling
call get_s2(psi_keys_tmp(1,1,i),psi_keys_tmp(1,1,i),N_int,s2_tmp)
accu += psi_coefs_tmp(i,ll) * s2_tmp * psi_coefs_tmp(i,jj)
call filter_connected(psi_keys_tmp,psi_keys_tmp(1,1,i),N_int,i-1,idx)
do kk=1,idx(0)
j = idx(kk)
call get_s2(psi_keys_tmp(1,1,i),psi_keys_tmp(1,1,j),N_int,s2_tmp)
accu += psi_coefs_tmp(i,ll) * s2_tmp * psi_coefs_tmp(j,jj) + psi_coefs_tmp(i,jj) * s2_tmp * psi_coefs_tmp(j,ll)
enddo
enddo
!$OMP END DO
deallocate(idx)
!$OMP END PARALLEL
s2(ll,jj) += accu
enddo
enddo
do i = 1, nstates
do j =i+1,nstates
accu = 0.5d0 * (s2(i,j) + s2(j,i))
s2(i,j) = accu
s2(j,i) = accu
enddo
enddo
end
subroutine i_S2_psi_minilist(key,keys,idx_key,N_minilist,coef,Nint,Ndet,Ndet_max,Nstate,i_S2_psi_array)
use bitmasks
implicit none
integer, intent(in) :: Nint, Ndet,Ndet_max,Nstate,idx_key(Ndet), N_minilist
integer(bit_kind), intent(in) :: keys(Nint,2,Ndet)
integer(bit_kind), intent(in) :: key(Nint,2)
double precision, intent(in) :: coef(Ndet_max,Nstate)
double precision, intent(out) :: i_S2_psi_array(Nstate)
integer :: i, ii,j, i_in_key, i_in_coef
double precision :: phase
integer :: exc(0:2,2,2)
double precision :: s2ij
integer :: idx(0:Ndet)
BEGIN_DOC
! Computes $\langle i|S^2|\Psi \rangle = \sum_J c_J \langle i|S^2|J \rangle$.
!
! Uses filter_connected_i_H_psi0 to get all the $|J\rangle$ to which $|i\rangle$
! is connected. The $|J\rangle$ are searched in short pre-computed lists.
END_DOC
ASSERT (Nint > 0)
ASSERT (N_int == Nint)
ASSERT (Nstate > 0)
ASSERT (Ndet > 0)
ASSERT (Ndet_max >= Ndet)
i_S2_psi_array = 0.d0
call filter_connected_i_H_psi0(keys,key,Nint,N_minilist,idx)
if (Nstate == 1) then
do ii=1,idx(0)
i_in_key = idx(ii)
i_in_coef = idx_key(idx(ii))
!DIR$ FORCEINLINE
call get_s2(keys(1,1,i_in_key),key,Nint,s2ij)
! TODO : Cache misses
i_S2_psi_array(1) = i_S2_psi_array(1) + coef(i_in_coef,1)*s2ij
enddo
else
do ii=1,idx(0)
i_in_key = idx(ii)
i_in_coef = idx_key(idx(ii))
!DIR$ FORCEINLINE
call get_s2(keys(1,1,i_in_key),key,Nint,s2ij)
do j = 1, Nstate
i_S2_psi_array(j) = i_S2_psi_array(j) + coef(i_in_coef,j)*s2ij
enddo
enddo
endif
end