anchor.diff:           t2 = t*t
            t4 = t2*t2
            B = -ec_lda/GAMMA
  -         B = BOG/(exp(B)-1.0d0+ETA)
  +         B = BOG/(dexp(B)-1.0d0+ETA)
            Q4 = 1.0d0 + B*t2
            Q5 = 1.0d0 + B*t2 + B*B*t4
            H = GAMMA*dlog(1.0d0 + BOG*Q4*t2/Q5)
  
positive.code: 
           Ht  = 2.0d0*BETA*Q9/Q8*t
  
           ec   = ec_lda + malphac*H
           fnc  = ec  - (onethird*rs*ec_lda_rs)
       >             - malphac*(onethird*rs*Hrs)
       >             - malphac*(sevensixths*t*Ht)
           fdnc = malphac*(0.5d0* Ht/ks)
  
negative.code: 
           fdn(i,1) = x_parameter*fdnxup 
           fdn(i,2) = x_parameter*fdnxdn 
           fdn(i,3) = c_parameter*t_agr*Hpbe_t*malphac
  
        end do
  !$OMP END DO
  