anchor.diff:  
        call rescale_at_walls
        call wall_mpcd_step(solvent, solvent_cells, state, &
  -          wall_temperature=wall_t, wall_v=wall_v, wall_n=[rho, rho])
  +          wall_temperature=wall_t, wall_v=wall_v, wall_n=[rho, rho], alpha=alpha)
   
        if (i>N_therm) then
           temperature = compute_temperature(solvent, solvent_cells, tz)
  
positive.code:   double precision :: v_com(3), wall_v(3,2), wall_t(2)
  
    double precision :: e1, e2
    double precision :: tau, dt , T
    double precision :: skin, co_max, so_max
    integer :: N_MD_steps, N_loop
    integer :: N_therm
  
negative.code:   rho = PTread_i(config, 'rho')
    N = rho *L(1)*L(2)*L(3)
    tau =PTread_d(config, 'tau')
    alpha = PTread_d(config,'alpha')
  
    N_MD_steps = PTread_i(config, 'N_MD')
    dt = tau / N_MD_steps
  