anchor.diff:    type(scalar_field):: lapu
     type(scalar_field):: lapu_exact
     type(scalar_field):: lapu_error
  +
  +  !Gradient of divergence (at edges) - used in diffusion
  +  type(scalar_field):: grad_ed_div
  +
  +  !Gradient of relative vorticity (at edges) - used in diffusion
  +  type(scalar_field):: grad_ed_vort
   
     !Trsk consistency index
     type(scalar_field):: trskind !Low values indicate godd for trisk
  
positive.code:   type(scalar_field):: q_ed  !pv on edges
    type(scalar_field):: q_ed_exact  !pv on edges
    type(scalar_field):: q_ed_error  !pv on edges
  
  
    type(scalar_field):: q_grad_ed  !grad pv on edges
  
negative.code: 
      !Laplacian
      lapu%f=0._r8
  
      !Gradients
      !grad_ed_div%f =0._r8
      !grad_ed_vort%f =0._r8
  
      !PV analysis
      q_tr_exact=q_tr
  