anchor.diff:                  if(all(current_pos == spawning_head+1)) exit
                   
               end do
  +
  +            do_annihilation
  +            if(vary_shift) update_shift
  +            print_out
  +
           end do
   
       end subroutine do_tc_fciqmc
   
       
  -    subroutine ct_spawn(d, parent_sgn, nspawned, connection)
  +    subroutine ct_spawn_real(d, K_ii, parent_sgn, matel, nspawned, connection)
       
           ! randomly select a (valid) excitation from the current determinant
  -        ! stored in "d"
  +        ! stored in "d" for the Hubbard model in realspace
           !
           ! In: 
           !    d: info on current determinant that we will spawn from.
  +        !    R_ii: the diagonal Hamiltonian matrix element for the determinant d
           !    parent_sgn: sgn on the parent determinant (i.e. +ve or -ve integer)
           !
           ! Out:
  
positive.code:     ! Array to hold the spawned times of the walkers
  real(p), allocatable :: spawn_times(:) ! (spawned_walker_length)
  
  contains
      subroutine do_tc_fciqmc()
          
          integer :: nspawned, ireport, idet, iparticle
          integer, allocatable :: current_pos(:) ! (0:max(1,nprocs-1))
  
negative.code:                     end do
  
                  end do
                  
                  walker_population(1,idet) = tmp_pop
              
              end do
  
              ! now we advance all the spawned walkers to the barrier from their
  