anchor.diff:          call vx% reset()
        end if
   
  +     call varia%tic()
        call compute_rho_xy
  +     call varia%tac()
        call rho_xy_el%append(rho_xy)
   
        call solvent% sort(solvent_cells)
  
positive.code:         co_max = colloids% maximum_displacement()
  
          if ( (co_max >= skin/2) .or. (so_max >= skin/2) ) then
             call apply_pbc(solvent, solvent_cells% edges)
             call apply_pbc(colloids, solvent_cells% edges)
             call solvent% sort(solvent_cells)
             call neigh% update_list(colloids, solvent, max_cut + skin, solvent_cells)
             solvent% pos_old = solvent% pos
             colloids% pos_old = colloids% pos
             n_extra_sorting = n_extra_sorting + 1
          end if
  
  
negative.code:   call flag_timer%init('flag')
    call change_timer%init('change')
    call buffer_timer%init('buffer')
    call varia%init('varia')
  
    n_threads = omp_get_max_threads()
    allocate(state(n_threads))
  