anchor.diff:             call apply_pbc(colloids, solvent_cells% edges)
              call varia%tac()
              call solvent% sort(solvent_cells)
  -           call neigh% update_list(colloids, solvent, max_cut + skin, solvent_cells)
  +           call neigh% update_list(colloids, solvent, max_cut + skin, solvent_cells, solvent_colloid_lj)
              call varia%tic()
              !$omp parallel do
              do k = 1, solvent%Nmax
  
positive.code:      call solvent_cells%random_shift(state(1))
       call varia%tac()
  
       call solvent% sort(solvent_cells)
       call neigh% update_list(colloids, solvent, max_cut+skin, solvent_cells)
       call varia%tic()
       !$omp parallel do
       do k = 1, solvent%Nmax
  
negative.code: 
    call neigh% make_stencil(solvent_cells, max_cut+skin)
  
    call neigh% update_list(colloids, solvent, max_cut+skin, solvent_cells, solvent_colloid_lj)
  
    cyl_shell_rmin = max(sigma_N, sigma_C)
    cyl_shell_rmax = cyl_shell_rmin + 2
  