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https://github.com/LCPQ/quantum_package
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94 lines
3.7 KiB
Fortran
94 lines
3.7 KiB
Fortran
subroutine get_excitation_operators_for_one_ref(det_ref,i_state,ndetnonref,N_connect_ref,excitation_operators,amplitudes_phase_less,index_connected)
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use bitmasks
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implicit none
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integer(bit_kind), intent(in) :: det_ref(N_int,2)
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integer, intent(in) :: i_state,ndetnonref
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integer*2, intent(out) :: excitation_operators(5,ndetnonref)
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integer, intent(out) :: index_connected(ndetnonref)
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integer, intent(out) :: N_connect_ref
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double precision, intent(out) :: amplitudes_phase_less(ndetnonref)
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integer :: i,j,k,l,degree,h1,p1,h2,p2,s1,s2
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integer :: exc(0:2,2,2)
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double precision :: phase,hij
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BEGIN_DOC
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! This subroutine provides all the amplitudes and excitation operators
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! that one needs to go from the reference to the non reference wave function
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! you enter with det_ref that is a reference determinant
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!
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! N_connect_ref is the number of determinants belonging to psi_non_ref
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! that are connected to det_ref.
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!
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! amplitudes_phase_less(i) = amplitude phase less t_{I->i} = <I|H|i> * lambda_mrcc(i) * phase(I->i)
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!
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! excitation_operators(:,i) represents the holes and particles that
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! link the ith connected determinant to det_ref
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! if ::
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! excitation_operators(5,i) = 2 :: double excitation alpha
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! excitation_operators(5,i) = -2 :: double excitation beta
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!!! excitation_operators(1,i) :: hole 1
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!!! excitation_operators(2,i) :: particle 1
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!!! excitation_operators(3,i) :: hole 2
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!!! excitation_operators(4,i) :: particle 2
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! else if ::
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! excitation_operators(5,i) = 1 :: single excitation alpha
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!!! excitation_operators(1,i) :: hole 1
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!!! excitation_operators(2,i) :: particle 1
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! else if ::
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! excitation_operators(5,i) = -1 :: single excitation beta
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!!! excitation_operators(3,i) :: hole 1
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!!! excitation_operators(4,i) :: particle 1
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! else if ::
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!!! excitation_operators(5,i) = 0 :: double excitation alpha/beta
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!!! excitation_operators(1,i) :: hole 1 alpha
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!!! excitation_operators(2,i) :: particle 1 alpha
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!!! excitation_operators(3,i) :: hole 2 beta
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!!! excitation_operators(4,i) :: particle 2 beta
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END_DOC
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N_connect_ref = 0
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do i = 1, ndetnonref
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call i_H_j_phase_out(det_ref,psi_non_ref(1,1,i),N_int,hij,phase,exc,degree)
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if (dabs(hij) <= mo_integrals_threshold) then
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cycle
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endif
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N_connect_ref +=1
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index_connected(N_connect_ref) = i
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call decode_exc(exc,degree,h1,p1,h2,p2,s1,s2)
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amplitudes_phase_less(N_connect_ref) = hij * lambda_mrcc(i_state,i) !*phase
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if (degree==2) then
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excitation_operators(1,N_connect_ref) = h1
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excitation_operators(2,N_connect_ref) = p1
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excitation_operators(3,N_connect_ref) = h2
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excitation_operators(4,N_connect_ref) = p2
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if(s1==s2.and.s1==1)then ! double alpha
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excitation_operators(5,N_connect_ref) = 2
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elseif(s1==s2.and.s1==2)then ! double beta
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excitation_operators(5,N_connect_ref) = -2
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else ! double alpha/beta
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excitation_operators(5,N_connect_ref) = 0
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endif
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else if(degree==1) then
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if(s1==1)then ! mono alpha
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excitation_operators(5,N_connect_ref) = 1
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excitation_operators(1,N_connect_ref) = h1
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excitation_operators(2,N_connect_ref) = p1
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else ! mono beta
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excitation_operators(5,N_connect_ref) = -1
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excitation_operators(3,N_connect_ref) = h1
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excitation_operators(4,N_connect_ref) = p1
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endif
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else
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N_connect_ref-=1
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endif
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enddo
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end
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