anchor.diff:          call nwpw_GVT4(aa,bb,cc,dd,ee,ff,alpha,alpha,
        >              xr,zr,gamma,GG,dGdx,dGdz)
   
  -        ex     = 2.0d0*n_13*GG
  -        fnx    = 2.0d0*(frthrd*n_13*GG + n_43*(dGdx*dxdn + dGdz*dzdn))
  -        fdnx   = 2.0d0*n_43*(dGdx*dxdagr)
  -        fdtaux = 2.0d0*n_43*(dGdz*dzdtau) 
  +        ex     = n_13*GG
  +        fnx    = (frthrd*n_13*GG + n_43*(dGdx*dxdn + dGdz*dzdn))
  +        fdnx   = n_43*(dGdx*dxdagr)
  +        fdtaux = n_43*(dGdz*dzdtau) 
   
   ********* VS98 Correlation *********
   ********* Same-spin *********
  
positive.code:       call gen_PW92_BW_restricted(n2ft3d,rho_in,ec0,fnc0)
  
        do i=1,n2ft3d
          n       = 0.50d0*rho_in(i) + ETA
          agr     = 0.50d0*agr_in(i)
          tau     = 0.50d0*tau_in(i)
          ec_LDA  = 0.50d0*ec0(i)
          fnc_LDA = 0.50d0*fnc0(i)
  
         !if (n .gt. tol)  then
  
  
negative.code:      >               x,z,gamma,xr,zr,
       >               dxdn,dxdagr,dzdn,dzdtau,
       >               ec,fnc,fdnc,fdtauc)
  
  c      else
  c         ex = 0.0d0
  