anchor.diff:          allocate(sweet_level_t::pf%levels(level)%ulevel)
           allocate(sweet_data_factory_t::pf%levels(level)%ulevel%factory)
           allocate(sweet_sweeper_t::pf%levels(level)%ulevel%sweeper)
  -        
  -        ! check the number of nodes for RK stepper
  -        if (pf%use_rk_stepper .eqv. .true.) then
  -            if (pf%levels(level)%ulevel%stepper%order      == 5 .and. nnodes(level) /= 9) then
  -                stop "invalid number of nodes for the RK stepper"
  -            else if (pf%levels(level)%ulevel%stepper%order == 4 .and. nnodes(level) /= 7) then
  -                stop "invalid number of nodes for the RK stepper"
  -            else if (pf%levels(level)%ulevel%stepper%order == 3 .and. nnodes(level) /= 5) then
  -                stop "invalid number of nodes for the RK stepper"
  -            else if (pf%levels(level)%ulevel%stepper%order == 2 .and. nnodes(level) /= 4) then
  -                stop "invalid number of nodes for the RK stepper"
  -            end if
  -        end if
   
           ! cast the object into sweet data objects
           sd_factory_ptr    => as_sweet_data_factory(pf%levels(level)%ulevel%factory)
  
positive.code:                          PF_POST_BLOCK,       &
                           fecho_output_invariants)
          
          ! advance in time with libpfasst
          level = nlevs
  
  
negative.code:     use feval_module
      use hooks_module
      use transfer_module
      use pf_mod_parallel
      use pf_mod_mpi
      use pfasst
  