anchor.diff:  
           integer, allocatable :: cumulative_abs_pops(:)
           integer :: D0_pos, max_cluster_size,tot_abs_pop
  +        integer :: D0_normalisation
           logical :: hit
           type(bloom_stats_t) :: bloom_stats
   
  
positive.code:                 !$omp do schedule(dynamic,200) private(nspawned, connection, junk) reduction(+:D0_population_cycle,proj_energy)
                  do iattempt = 1, nattempts
  
                      call select_cluster(rng(it), nattempts, D0_pos, cumulative_abs_pops, tot_abs_pop, max_cluster_size, &
                                          cdet(it), cluster(it))
  
                      if (cluster(it)%excitation_level <= truncation_level+2) then
  
  
negative.code:         ! In:
          !    nattempts: the number of times (on this processor) a random cluster
          !        of excitors is generated in the current timestep.
          !    normalisation: intermediate normalisation factor, N_0, where we use the
          !       wavefunction ansatz |\Psi_{CC}> = N_0 e^{T/N_0} | D_0 >.
          !    D0_pos: position in the excip list of the reference.
          !    cumulative_excip_population: running cumulative excip population on
          !        all excitors; i.e. cumulative_excip_population(i) = sum(walker_population(1:i)).
  