subroutine dradb4 (ido,l1,cc,ch,wa1,wa2,wa3)
      double precision cc(ido,4,l1), ch(ido,l1,4), wa1(1), wa2(1),
     1  wa3(1), ci2, ci3, ci4, cr2, cr3, cr4, sqrt2, ti1, ti2, ti3, ti4,
     2  tr1, tr2, tr3, tr4
      data sqrt2 /  1.414213562 3730950488 0168872420 970 d0 /
c
      do 101 k=1,l1
         tr1 = cc(1,1,k)-cc(ido,4,k)
         tr2 = cc(1,1,k)+cc(ido,4,k)
         tr3 = cc(ido,2,k)+cc(ido,2,k)
         tr4 = cc(1,3,k)+cc(1,3,k)
         ch(1,k,1) = tr2+tr3
         ch(1,k,2) = tr1-tr4
         ch(1,k,3) = tr2-tr3
         ch(1,k,4) = tr1+tr4
  101 continue
c
      if (ido-2) 107,105,102
  102 idp2 = ido+2
      do 104 k=1,l1
         do 103 i=3,ido,2
            ic = idp2-i
            ti1 = cc(i,1,k)+cc(ic,4,k)
            ti2 = cc(i,1,k)-cc(ic,4,k)
            ti3 = cc(i,3,k)-cc(ic,2,k)
            tr4 = cc(i,3,k)+cc(ic,2,k)
            tr1 = cc(i-1,1,k)-cc(ic-1,4,k)
            tr2 = cc(i-1,1,k)+cc(ic-1,4,k)
            ti4 = cc(i-1,3,k)-cc(ic-1,2,k)
            tr3 = cc(i-1,3,k)+cc(ic-1,2,k)
            ch(i-1,k,1) = tr2+tr3
            cr3 = tr2-tr3
            ch(i,k,1) = ti2+ti3
            ci3 = ti2-ti3
            cr2 = tr1-tr4
            cr4 = tr1+tr4
            ci2 = ti1+ti4
            ci4 = ti1-ti4
            ch(i-1,k,2) = wa1(i-2)*cr2-wa1(i-1)*ci2
            ch(i,k,2) = wa1(i-2)*ci2+wa1(i-1)*cr2
            ch(i-1,k,3) = wa2(i-2)*cr3-wa2(i-1)*ci3
            ch(i,k,3) = wa2(i-2)*ci3+wa2(i-1)*cr3
            ch(i-1,k,4) = wa3(i-2)*cr4-wa3(i-1)*ci4
            ch(i,k,4) = wa3(i-2)*ci4+wa3(i-1)*cr4
  103    continue
  104 continue
      if (mod(ido,2) .eq. 1) return
c
  105 continue
      do 106 k=1,l1
         ti1 = cc(1,2,k)+cc(1,4,k)
         ti2 = cc(1,4,k)-cc(1,2,k)
         tr1 = cc(ido,1,k)-cc(ido,3,k)
         tr2 = cc(ido,1,k)+cc(ido,3,k)
         ch(ido,k,1) = tr2+tr2
         ch(ido,k,2) = sqrt2*(tr1-ti1)
         ch(ido,k,3) = ti2+ti2
         ch(ido,k,4) = -sqrt2*(tr1+ti1)
  106 continue
c
  107 return
      end