anchor.diff:      if(allocated(this%oid)) deallocate(this%oid)
       if(allocated(this%lvl)) deallocate(this%lvl)
       if(allocated(this%neib)) deallocate(this%neib)
  +    if(allocated(this%flag)) deallocate(this%flag)
     end subroutine
     
     !> position of cell k
  
positive.code:     allocate(this%oid(this%nC))
      allocate(this%lvl(this%nC))
      allocate(this%neib(N_FACE,this%nC))
      call ot_genConn(this%otree,this%oid,this%lvl,this%neib)
    end subroutine
    
    !> clear this otGrid
  
negative.code:   integer,parameter::DIMS=3 !< dimensions
    integer,parameter::N_FACE=6 !< number of faces per cell
    
    ! public constants
    integer,parameter,public::OT_OUT=0
    integer,parameter,public::OT_IN=1
    integer,parameter,public::OT_CUT=2
    
    !> octree grid
    type,public::otGrid
      ! basic data
  