anchor.diff:      r0=zero
       do l=1,this%lz
         dj=real(this%ij_TAz(2,l,z), fPrec)
  -      if ((dj>zero).and.(this%ij_TAz(1,l,z)<=max_i).and.(this%ij_TAz(2,l,z)-1<=max_j)) then
  +      if ((dj>zero).and.(this%ij_TAz(1,l,z)<=max_i_l).and.(this%ij_TAz(2,l,z)-1<=max_j_l)) then
           r0 = r0 + dj*(xpow(this%ij_TAz(1,l,z))*(ypow(this%ij_TAz(2,l,z)-1)*this%TAz(l,z)))
         endif
       enddo
  
positive.code:     ! Mod from SixTrack
      ! ---------------------------------------------------------------------------------------------- !
      use numerical_constants, only : half
  
      implicit none
  
      ! interface variables
      ! ---------------------------------------------------------------------------------------------- !
      class(ffTable_n_Track), intent(in)    :: this
      real(kind=fPrec),       intent(in)    :: deltap1
      real(kind=fPrec),       intent(inout) :: zb
      real(kind=fPrec),       intent(inout) :: x,px,y,py ! Transverse canonical parameter in new referencial
  
negative.code:     ! ---------------------------------------------------------------------------------------------- !
      r0=zero
      do l=1,this%lx
        if ((this%ij_TAx(1,l,z)<=max_i_l).and.(this%ij_TAx(2,l,z)<=max_j_l)) then
          r0 = r0 + xpow(this%ij_TAx(1,l,z))*(ypow(this%ij_TAx(2,l,z))*this%TAx(l,z))
        endif
      enddo
  