subroutine dradf3 (ido,l1,cc,ch,wa1,wa2)
      double precision cc(ido,l1,3), ch(ido,3,l1), wa1(1), wa2(1),
     1  ci2, cr2, di2, di3, dr2, dr3, taui, taur, ti2, ti3, tr2, tr3
      data taur / -0.5 d0 /
      data taui  /  0.8660254037 8443864676 3723170752 93618d0/
c
      do 101 k=1,l1
         cr2 = cc(1,k,2)+cc(1,k,3)
         ch(1,1,k) = cc(1,k,1)+cr2
         ch(1,3,k) = taui*(cc(1,k,3)-cc(1,k,2))
         ch(ido,2,k) = cc(1,k,1)+taur*cr2
  101 continue
c
      if (ido .eq. 1) return
      idp2 = ido+2
      do 103 k=1,l1
         do 102 i=3,ido,2
            ic = idp2-i
            dr2 = wa1(i-2)*cc(i-1,k,2)+wa1(i-1)*cc(i,k,2)
            di2 = wa1(i-2)*cc(i,k,2)-wa1(i-1)*cc(i-1,k,2)
            dr3 = wa2(i-2)*cc(i-1,k,3)+wa2(i-1)*cc(i,k,3)
            di3 = wa2(i-2)*cc(i,k,3)-wa2(i-1)*cc(i-1,k,3)
            cr2 = dr2+dr3
            ci2 = di2+di3
            ch(i-1,1,k) = cc(i-1,k,1)+cr2
            ch(i,1,k) = cc(i,k,1)+ci2
            tr2 = cc(i-1,k,1)+taur*cr2
            ti2 = cc(i,k,1)+taur*ci2
            tr3 = taui*(di2-di3)
            ti3 = taui*(dr3-dr2)
            ch(i-1,3,k) = tr2+tr3
            ch(ic-1,2,k) = tr2-tr3
            ch(i,3,k) = ti2+ti3
            ch(ic,2,k) = ti3-ti2
  102    continue
  103 continue
c
      return
      end