anchor.diff:          allocate(det_info%symunocc(2,sys%sym0_tot:sys%sym_max_tot), stat=ierr)
           call check_allocate('det_info%symunocc', 2*sys%nsym_tot, ierr)
   
  +        ! Weights for excitation generators for this det. 
  +        allocate(det_info%i_d_weights(sys%nel), stat=ierr)
  +        call check_allocate('det_info%i_d_weights', sys%nel, ierr)
  +        allocate(det_info%i_s_weights(sys%nel), stat=ierr)
  +        call check_allocate('det_info%i_s_weights', sys%nel, ierr)
  +        allocate(det_info%ia_s_weights(sys%nvirt, sys%nel), stat=ierr)
  +        call check_allocate('det_info%ia_s_weights', sys%nvirt*sys%nel, ierr)
  +
  +        ! Orbitals that are different between this det and the ref det.
  +        allocate(det_info%diff_det_to_ref_orbs(sys%nel, sys%nel), stat=ierr)
  +        call check_allocate('det_info%diff_det_to_ref_orbs', sys%nel**2, ierr)
  +
       end subroutine alloc_det_info_t
   
       subroutine dealloc_det_info_t(det_info, allocated_bit_strings)
  
positive.code:         call check_deallocate('det_info%unocc_list_beta',ierr)
          deallocate(det_info%symunocc, stat=ierr)
          call check_deallocate('det_info%symunocc',ierr)
  
      end subroutine dealloc_det_info_t
  
  
negative.code:     ! The first index maps to spin using (Ms+3)/2, where Ms=-1 is spin-down and
      ! Ms=1 is spin-up.
      integer, pointer :: symunocc(:,:) ! (2,sym0_tot:sym_max_tot)
      ! heat_bath weights to select i in a double excitation
      real(p), pointer :: i_d_weights(:) ! (nel)
      ! heat bath weights to select i in a single excitation
      real(p), pointer :: i_s_weights(:) ! (nel)
      ! heat bath weights to select a given i in a single excitation
      real(p), pointer :: ia_s_weights(:,:) ! (virt, nel)
      ! position of different orbitals in this det compared to reference
      ! First column refers to orbitals in reference, second column to corresponding orbitals in det.
      integer, pointer :: diff_det_to_ref_orbs(:,:) ! (nel, 2)
      ! Number of orbitals that are different between det and reference.
      integer :: nex
      ! is the determinant an initiator determinant or not? (used only in
      ! i-FCIQMC). The i-th bit is set if the determinant is not an initiator in
      ! space i.
  