anchor.diff:  
            kf = (3.0d0*pi*pi*n)**onethird
            ks = dsqrt(4.0d0*kf/pi)
  -         t  = agr/(2.0*ks*n)
  +         t  = agr/(2.0d0*ks*n)
  +
   
   c        **** unpolarized LDA correlation energy ****
   c        **** ec_p = correlation energy          ****
   c        ****   ec_p_rs = dec_p/drs              ****
   c        ****   uc_p    = dec_p/dn               ****
  -         CALL LSDT2(A_1,A1_1,B1_1,B2_1,B3_1,B4_1,rss,ec_lda,ec_lda_rs)
  -      
  +         call LSDT2(A_1,A1_1,B1_1,B2_1,B3_1,B4_1,rss,ec_lda,ec_lda_rs)
   c        **** PBE96 correlation energy  corrections ****
            t2 = t*t
            t4 = t2*t2
  
positive.code: *    *					*
  *    ************************************
  *
  *    This function returns the PBE96 exchange-correlation
  *  energy density, xce, and its derivatives with respect
  *  to nup, ndn, |grad nup|, |grad ndn|, and |grad n|.
  *
  
negative.code: c     **** other constants ****
        real*8 onethird,fourthird,fivethird,onesixthm
        real*8 twothird,sevensixthm
        real*8 onethirdm
        parameter (onethird=1.0d0/3.0d0)
        parameter (onethirdm=-1.0d0/3.0d0)
        parameter (twothird=2.0d0/3.0d0)
  