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126 lines
3.8 KiB
Fortran
126 lines
3.8 KiB
Fortran
use bitmasks
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subroutine do_signed_mono_excitation(key1,key2,nu,ihole,ipart, &
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ispin,phase,ierr)
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BEGIN_DOC
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! we create the mono-excitation, and determine, if possible,
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! the phase and the number in the list of determinants
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END_DOC
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implicit none
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integer(bit_kind) :: key1(N_int,2),key2(N_int,2)
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integer(bit_kind), allocatable :: keytmp(:,:)
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integer :: exc(0:2,2,2),ihole,ipart,ierr,nu,ispin
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real*8 :: phase
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logical :: found
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allocate(keytmp(N_int,2))
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nu=-1
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phase=1.D0
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ierr=0
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call det_copy(key1,key2,N_int)
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! write(6,*) ' key2 before excitation ',ihole,' -> ',ipart,' spin = ',ispin
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! call print_det(key2,N_int)
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call do_single_excitation(key2,ihole,ipart,ispin,ierr)
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! write(6,*) ' key2 after ',ihole,' -> ',ipart,' spin = ',ispin
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! call print_det(key2,N_int)
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! write(6,*) ' excitation ',ihole,' -> ',ipart,' gives ierr = ',ierr
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if (ierr.eq.1) then
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! excitation is possible
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! get the phase
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call get_single_excitation(key1,key2,exc,phase,N_int)
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! get the number in the list
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found=.false.
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nu=0
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!TODO BOTTLENECK
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do while (.not.found)
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nu+=1
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if (nu.gt.N_det) then
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! the determinant is possible, but not in the list
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found=.true.
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nu=-1
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else
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call det_extract(keytmp,nu,N_int)
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integer :: i,ii
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found=.true.
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do ii=1,2
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do i=1,N_int
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if (keytmp(i,ii).ne.key2(i,ii)) then
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found=.false.
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end if
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end do
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end do
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end if
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end do
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end if
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!
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! we found the new string, the phase, and possibly the number in the list
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!
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end subroutine do_signed_mono_excitation
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subroutine det_extract(key,nu,Nint)
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BEGIN_DOC
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! extract a determinant from the list of determinants
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END_DOC
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implicit none
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integer :: ispin,i,nu,Nint
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integer(bit_kind) :: key(Nint,2)
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do ispin=1,2
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do i=1,Nint
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key(i,ispin)=psi_det(i,ispin,nu)
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end do
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end do
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end subroutine det_extract
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subroutine det_copy(key1,key2,Nint)
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use bitmasks ! you need to include the bitmasks_module.f90 features
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BEGIN_DOC
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! copy a determinant from key1 to key2
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END_DOC
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implicit none
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integer :: ispin,i,Nint
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integer(bit_kind) :: key1(Nint,2),key2(Nint,2)
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do ispin=1,2
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do i=1,Nint
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key2(i,ispin)=key1(i,ispin)
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end do
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end do
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end subroutine det_copy
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subroutine do_spinfree_mono_excitation(key_in,key_out1,key_out2 &
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,nu1,nu2,ihole,ipart,phase1,phase2,ierr,jerr)
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BEGIN_DOC
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! we create the spin-free mono-excitation E_pq=(a^+_p a_q + a^+_P a_Q)
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! we may create two determinants as result
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!
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END_DOC
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implicit none
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integer(bit_kind) :: key_in(N_int,2),key_out1(N_int,2)
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integer(bit_kind) :: key_out2(N_int,2)
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integer :: ihole,ipart,ierr,jerr,nu1,nu2
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integer :: ispin
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real*8 :: phase1,phase2
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! write(6,*) ' applying E_',ipart,ihole,' on determinant '
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! call print_det(key_in,N_int)
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! spin alpha
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ispin=1
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call do_signed_mono_excitation(key_in,key_out1,nu1,ihole &
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,ipart,ispin,phase1,ierr)
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! if (ierr.eq.1) then
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! write(6,*) ' 1 result is ',nu1,phase1
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! call print_det(key_out1,N_int)
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! end if
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! spin beta
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ispin=2
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call do_signed_mono_excitation(key_in,key_out2,nu2,ihole &
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,ipart,ispin,phase2,jerr)
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! if (jerr.eq.1) then
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! write(6,*) ' 2 result is ',nu2,phase2
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! call print_det(key_out2,N_int)
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! end if
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end subroutine do_spinfree_mono_excitation
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