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Merge pull request #127 from QuantumPackage/kg-patch-s2

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rearrange s2 terms
This commit is contained in:
Anthony Scemama 2020-08-25 19:15:02 +02:00 committed by GitHub
commit 3edc33e05b
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3 changed files with 20 additions and 9 deletions
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4
src/davidson/diagonalization_hs2_dressed.irp.f
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@ -450,7 +450,7 @@ subroutine davidson_diag_hjj_sjj(dets_in,u_in,H_jj,s2_out,energies,dim_in,sze,N_
if (s2_eig) then
h_p = s_
do k=1,shift2
h_p(k,k) = h_p(k,k) + S_z2_Sz - expected_s2
h_p(k,k) = h_p(k,k) - expected_s2
enddo
if (only_expected_s2) then
alpha = 0.1d0
@ -496,7 +496,7 @@ subroutine davidson_diag_hjj_sjj(dets_in,u_in,H_jj,s2_out,energies,dim_in,sze,N_
0.d0, s_, size(s_,1))
do k=1,shift2
s2(k) = s_(k,k) + S_z2_Sz
s2(k) = s_(k,k)
enddo
if (only_expected_s2) then

2
src/davidson/diagonalize_ci.irp.f
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@ -107,7 +107,7 @@ END_PROVIDER
H_prime(1:N_det,1:N_det) = H_matrix_all_dets(1:N_det,1:N_det) + &
alpha * S2_matrix_all_dets(1:N_det,1:N_det)
do j=1,N_det
H_prime(j,j) = H_prime(j,j) + alpha*(S_z2_Sz - expected_s2)
H_prime(j,j) = H_prime(j,j) - alpha*expected_s2
enddo
call lapack_diag(eigenvalues,eigenvectors,H_prime,size(H_prime,1),N_det)
CI_electronic_energy(:) = 0.d0

23
src/determinants/s2.irp.f
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@ -8,24 +8,35 @@ double precision function diag_S_mat_elem(key_i,Nint)
BEGIN_DOC
! Returns <i|S^2|i>
END_DOC
integer :: nup, i
integer(bit_kind) :: xorvec(N_int_max)
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
xorvec(i) = iand(xorvec(i),key_i(i,1))
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
nup += popcnt(xorvec(i))
ntot += popcnt(xorvec(i))
if (upvec(i) /= 0_bit_kind) then
nup += popcnt(upvec(i))
endif
endif
enddo
diag_S_mat_elem = dble(nup)
double precision :: sz
sz = nup - 0.5d0*ntot
!<S^2> = <S+ S-> + Sz(Sz-1)
diag_S_mat_elem = nup + sz*(sz-1)
end
@ -125,7 +136,7 @@ subroutine u_0_S2_u_0(e_0,u_0,n,keys_tmp,Nint,N_st,sze_8)
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) + S_z2_Sz
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