anchor.diff:  c        ************
            n     = 2.0d0*nup
            agr   = 2.0d0*agrup
  -	 n13   = n**onethird         
  -	 n13   = max(n13,1.d-14)
  -         n_onethird = n13*((3.0d0/pi)**onethird)
  +
  +         n_onethird = (3.0d0*n/pi)**onethird
            ex_lda     = -0.75d0*n_onethird
   
  -         kf = n13*((3.0d0*pi*pi)**onethird)
  -         s  = agr/(2.0d0*kf*(n13**3))
  +         kf = (3.0d0*pi*pi*n)**onethird
  +         s  = agr/(2.0d0*kf*n)
            P0 = 1.0d0 + (MU/KAPPA)*s*s
   
            F   = (1.0d0 + KAPPA - KAPPA/P0)
  
positive.code: 
        
        do i=1,n2ft3d
           nup     = dn_in(i,1)
           agrup   = agr_in(i,1)
           ndn     = dn_in(i,2)
           agrdn   = agr_in(i,2)
  c        ****************************************************************
  c        ***** calculate polarized Exchange energies and potentials *****
  c        ****************************************************************
  
negative.code: 
  
           ec = ec_lda + Hpbe
  
  c        fncup  = ec + n*(ec_lda_nup + Hpbe_nup)
  c        fncdn  = ec + n*(ec_lda_ndn + Hpbe_ndn)
           fncup  = ec + (ec_lda_nup + Hpbe_nup)
           fncdn  = ec + (ec_lda_ndn + Hpbe_ndn)
  
  
           xce(i)   = x_parameter*ex     + c_parameter*ec
           fn(i,1)  = x_parameter*fnxup  + c_parameter*fncup
           fn(i,2)  = x_parameter*fnxdn  + c_parameter*fncdn
  
           fdn(i,1) = x_parameter*fdnxup 
           fdn(i,2) = x_parameter*fdnxdn 
           fdn(i,3) = c_parameter*t_agr*Hpbe_t
  