anchor.diff:          use ccmc_data, only: cluster_t
           use excitations, only: get_excitation_level
           use dSFMT_interface, only: genrand_real2
  -        use fciqmc_data, only: f0, tot_walkers, walker_population, walker_dets
  +        use fciqmc_data, only: f0, tot_walkers, walker_population, walker_dets, initiator_population
           use proc_pointers, only: decoder_ptr
           use utils, only: factorial
   
  
positive.code:         end if
          cluster%pselect = cluster%pselect*psize
  
          select case(cluster%nexcitors)
          case(0)
              ! Must be the reference.
  
negative.code:             cluster%excitation_level = 0
              cluster%amplitude = D0_normalisation
              cluster%cluster_to_det_sign = 1
              if (cluster%amplitude <= initiator_population) then
                  ! Something has gone seriously wrong and the CC
                  ! approximation is (most likely) not suitably for this system.
                  ! Let the user be an idiot if they want to be...
                  cdet%initiator_flag = 1
              end if
              ! Only one cluster of this size to choose => p_clust = 1
          case default
              ! Select cluster from the excitors on the current processor in
  