anchor.diff:      !! Setup the vertical grid structure, in case SLEVE coordinates are not used.
       !!    This means either constant vertical height, or a simple terrain following coordinate (Gal-Chen)
       !!
  -    !! -------------------------------- 
  +    !! --------------------------------
       subroutine setup_simple_z(this, options)
           implicit none
           class(domain_t), intent(inout)  :: this
  
positive.code:             ! this is on the subset grid:
              z_interface(:,i,:) = temp(ims:ime,i,jms:jme)
              z_interface(:,i+1,:) = temp(ims:ime,i+1,jms:jme)
             
              dz_interface(:,i,:)  =  z_interface(:,i+1,:) - z_interface(:,i,:)  ! same for higher k
  
              dz_mass(:,i,:)       = dz_interface(:,i,:) / 2           ! Diff for k=1
  
negative.code: 
  
      !> -------------------------------
      !! Setup the SLEVE vertical grid structure.
      !!   This basically entails 2 transformations: First a linear one so that sum(dz) ranges from 0 to smooth_height H.
      !!   (boundary cnd (3) in Schär et al 2002)  Next, the nonlinear SLEVE transformation
      !!    eqn (2) from Leuenberger et al 2009 z_sleve = Z + terrain * sinh((H/s)**n - (Z/s)**n) / SINH((H/s)**n) (for both smallscale and largescale terrain)
  