00001 subroutine passb4 (ido,l1,cc,ch,wa1,wa2,wa3)
00002 dimension cc(ido,4,l1) ,ch(ido,l1,4) ,
00003 1 wa1(1) ,wa2(1) ,wa3(1)
00004 if (ido .ne. 2) go to 102
00005 do 101 k=1,l1
00006 ti1 = cc(2,1,k)-cc(2,3,k)
00007 ti2 = cc(2,1,k)+cc(2,3,k)
00008 tr4 = cc(2,4,k)-cc(2,2,k)
00009 ti3 = cc(2,2,k)+cc(2,4,k)
00010 tr1 = cc(1,1,k)-cc(1,3,k)
00011 tr2 = cc(1,1,k)+cc(1,3,k)
00012 ti4 = cc(1,2,k)-cc(1,4,k)
00013 tr3 = cc(1,2,k)+cc(1,4,k)
00014 ch(1,k,1) = tr2+tr3
00015 ch(1,k,3) = tr2-tr3
00016 ch(2,k,1) = ti2+ti3
00017 ch(2,k,3) = ti2-ti3
00018 ch(1,k,2) = tr1+tr4
00019 ch(1,k,4) = tr1-tr4
00020 ch(2,k,2) = ti1+ti4
00021 ch(2,k,4) = ti1-ti4
00022 101 continue
00023 return
00024 102 do 104 k=1,l1
00025 do 103 i=2,ido,2
00026 ti1 = cc(i,1,k)-cc(i,3,k)
00027 ti2 = cc(i,1,k)+cc(i,3,k)
00028 ti3 = cc(i,2,k)+cc(i,4,k)
00029 tr4 = cc(i,4,k)-cc(i,2,k)
00030 tr1 = cc(i-1,1,k)-cc(i-1,3,k)
00031 tr2 = cc(i-1,1,k)+cc(i-1,3,k)
00032 ti4 = cc(i-1,2,k)-cc(i-1,4,k)
00033 tr3 = cc(i-1,2,k)+cc(i-1,4,k)
00034 ch(i-1,k,1) = tr2+tr3
00035 cr3 = tr2-tr3
00036 ch(i,k,1) = ti2+ti3
00037 ci3 = ti2-ti3
00038 cr2 = tr1+tr4
00039 cr4 = tr1-tr4
00040 ci2 = ti1+ti4
00041 ci4 = ti1-ti4
00042 ch(i-1,k,2) = wa1(i-1)*cr2-wa1(i)*ci2
00043 ch(i,k,2) = wa1(i-1)*ci2+wa1(i)*cr2
00044 ch(i-1,k,3) = wa2(i-1)*cr3-wa2(i)*ci3
00045 ch(i,k,3) = wa2(i-1)*ci3+wa2(i)*cr3
00046 ch(i-1,k,4) = wa3(i-1)*cr4-wa3(i)*ci4
00047 ch(i,k,4) = wa3(i-1)*ci4+wa3(i)*cr4
00048 103 continue
00049 104 continue
00050 return
00051 end
1.7.1
