anchor.diff:  
     real(x_precision), dimension(n_cell) :: dist_crit
   
  +  call getarg(1,arg)
  +
     !----------------------------------------------
     ! Convergence criteria for S and T
     !----------------------------------------------
  
positive.code: 
          if (mod(iteration, output_freq) == 0) then
             call snapshot(s, iteration, t, 13)
             print*,'snapshot', iteration, t, 'exp', maxval(s%T - T_c), maxval(s%S - S_c), dt_T
          end if
  
  
negative.code:   real(x_precision), parameter         :: Smin   = 10._x_precision**1.0_x_precision
    real(x_precision), parameter         :: Smax   = 10._x_precision**3.5_x_precision
  
    real(x_precision), dimension(n_cell) :: T_c 
    real(x_precision), dimension(n_cell) :: Sigma_c 
    real(x_precision), dimension(n_cell) :: S_c
    !-------------------------------------------------------------------------
  
  