anchor.diff:                  nparticles = sign(nparticles, parent_sign)
               end if
   
  -            ! 6. Move to the next position in the spawning array.
  -            spawning_head = spawning_head + 1
  -
  -            ! 7. Set info in spawning array.
  -            call create_excited_det(cdet%f, connection, f_new)
  -            spawned_walker_dets(:,spawning_head) = f_new
  -            spawned_walker_population(spawning_head) = nparticles
  +            ! 6. Spawn.
  +            call create_spawned_particle(cdet, connection, nparticles)
   
   ! Leave the following in for debug reasons...
   ! Should be removed after more testing.
  -!            if (abs(get_hmatel_k(cdet%f,f_new)-s*hub_k_coulomb) > 1.e-10) then
  -!                write (6,*) 'huh?',get_hmatel_k(cdet%f,f_new), s*hub_k_coulomb,s
  +!            if (abs(get_hmatel_k(cdet%f,spawned_walker_dets(:,spawning_head))-s*hub_k_coulomb) > 1.e-10) then
  +!                write (6,*) 'huh?',get_hmatel_k(cdet%f,spawned_walker_dets(:,spawning_head)), s*hub_k_coulomb,s
   !                write (6,*) cdet%occ_list
  -!                write (6,*) i,j,a,b
  -!                write (6,*) connection%perm, mod(i-a,2) /= 0
  +!                write (6,*) connection%from_orb, connection %to_orb
  +!                write (6,*) connection%perm
   !                stop
   !            end if
   
  
positive.code: 
      end subroutine choose_ia_hub_real
  
  end module spawning
  
negative.code: 
          use determinants, only: det_info
          use dSFMT_interface, only:  genrand_real2
          use excitations, only: calc_pgen_hub_k, excit, find_excitation_permutation2
          use fciqmc_data, only: tau
          use system, only: hub_k_coulomb
  
  ! for debug only.
  !        use hamiltonian, only: get_hmatel_k
  !        use fciqmc_data, only: spawned_walker_dets, spawned_walker_population, spawning_head
  
          type(det_info), intent(in) :: cdet
          integer, intent(in) :: parent_sign
  
          real(p) :: pgen, psuccess, pspawn
          integer :: i, j, a, b, ij_sym, nparticles, s, tmp
          type(excit) :: connection
  
          ! Single excitations are not connected determinants within the 
  