anchor.diff:                  ! As we might select the reference determinant multiple times in
                   ! a cycle, the running total of D0_population is incorrect (by
                   ! a factor of the number of times it was selected).
  -                call search_walker_list(f0, 1, tot_walkers, hit, pos)
  -                D0_normalisation = walker_population(1,pos)
  +                call search_walker_list(f0, 1, tot_walkers, hit, D0_pos)
  +                D0_normalisation = walker_population(1,D0_pos)
   
                   ! Note that 'death' in CCMC creates particles in the spawned
                   ! list, so the number of deaths not in the spawned list is
  
positive.code: 
          logical :: soft_exit
  
          integer :: pos
          logical :: hit
  
          real :: t1, t2
  
negative.code:         use utils, only: factorial
  
          integer(lint), intent(in) :: nattempts
          integer, intent(in) :: D0_pos
          type(det_info), intent(inout) :: cdet
          type(cluster_t), intent(inout) :: cluster
  
  