anchor.diff:  
                       if (excitation_level <= truncation_level+2) then
   
  -                        ! TODO: projected estimator.
                           call update_proj_energy_ptr(cdet, cluster_amplitude)
   
                           call spawner_ccmc(cdet, cluster_amplitude, pcluster, nspawned, connection)
  
positive.code: 
      end subroutine stochastic_ccmc_death
  
  end module ccmc
  
negative.code:         case default
              ! Select cluster from the excitors on the current processor in
              ! a uniform manner.
              ! First excitor 'seeds' the cluster:
              pos = int(genrand_real2()*tot_walkers) +1
              cdet%f = walker_dets(:,pos)
              cluster_pop = walker_population(1,pos)
              ! Now the rest...
              do i = 2, cluster_size
                  ! Select a position between in the excitors list.
                  pos = int(genrand_real2()*tot_walkers) + 1
                  call collapse_cluster(walker_dets(:,pos), walker_population(1,pos), cdet%f, cluster_pop)
                  if (cluster_pop == 0) exit
              end do
  
              ! Normalisation factor for amplitudes...
              amplitude = real(cluster_pop,p)/(D0_population**(cluster_size-1)) ! TODO: don't accumulate D0 over report loops
  
              ! TODO: sign change due to difference between determinant
              ! representation and excitors.
  
              ! We chose excitors uniformly.
              !  -> prob. of each excitor is 1./(number of excitors on processor).
  