anchor.diff:  
       ! Do the isopycnal layer physics
       if (.not. RedGrav) then
  -      call isopycnal_correction(hnew, unew, vnew, eta, etanew, depth, a, &
  +      call barotropic_correction(hnew, unew, vnew, eta, etanew, depth, a, &
             dx, dy, wetmask, hfacW, hfacS, dt, &
             maxits, eps, rjac, freesurfFac, thickness_error, &
             g_vec, nx, ny, layers, n)
  
positive.code: ! ---------------------------------------------------------------------------
  !> Do the isopycnal layer physics
  
  subroutine isopycnal_correction(hnew, unew, vnew, eta, etanew, depth, a, &
      dx, dy, wetmask, hfacW, hfacS, dt, &
      maxits, eps, rjac, freesurfFac, thickness_error, &
      g_vec, nx, ny, layers, n)
  
negative.code:   call apply_boundary_conditions(vnew, hfacS, wetmask, nx, ny, layers)
  
    return
  end subroutine barotropic_correction
  
  ! ---------------------------------------------------------------------------
  !> Write output if it's time
  