subroutine sradb4 (ido,l1,cc,ch,wa1,wa2,wa3) real 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 e0 / 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