anchor.diff:      ! Current number of walkers stored in the main list (processor dependent).
       ! This is updated during annihilation and merging of the spawned walkers into
       ! the main list.
  +    ! [review] - FDM: rename (ndets perhaps)? Should this be here?
       integer :: tot_walkers
       ! Total number of particles on all walkers/determinants (processor dependent)
       ! Updated during death and annihilation and merging.
  
positive.code:     ! Population above which a determinant is an initiator.
      real(p) :: initiator_population = 3.0_p
  end type initiator_t
  
  ! Array to hold the indices of deterministic states in the dets array, accessed
  ! by calculating a hash value. This type is used by the semi_stoch_t type and
  
negative.code:     integer, allocatable :: correlation_sites(:)
  end type dmqmc_t
  
  ! [review] - FDM: Not sure where this belongs.
  ! When using the Neel singlet trial wavefunction, it is convenient
  ! to store all possible amplitudes in the wavefunction, since
  ! there are relativley few of them and they are expensive to calculate
  real(dp), allocatable :: neel_singlet_amp(:) ! (nsites/2) + 1
  
  ! [review] - FDM: Not sure where this belongs (spawned_walkers / walkers?).
  real(dp) :: annihilation_comms_time = 0.0_dp
  
  !--- Folded spectrum data ---
  