home *** CD-ROM | disk | FTP | other *** search
/ Language/OS - Multiplatform Resource Library / LANGUAGE OS.iso / cpp_libs / rwvector.lha / RWVector2.1 / src / mathpack / passb3.f < prev    next >
Text File  |  1989-08-14  |  2KB  |  49 lines
  1. *deck passb3
  2.       subroutine passb3 (ido,l1,cc,ch,wa1,wa2)
  3. C***BEGIN PROLOGUE  PASSB3
  4. C***REFER TO CFFTB
  5. C***ROUTINES CALLED  (NONE)
  6. C***END PROLOGUE  PASSB3
  7.       dimension       cc(ido,3,l1)           ,ch(ido,l1,3)           ,
  8.      1                wa1(1)     ,wa2(1)
  9.       data taur,taui /-.5,.866025403784439/
  10. C***FIRST EXECUTABLE STATEMENT  PASSB3
  11.       if (ido .ne. 2) go to 102
  12.       do 101 k=1,l1
  13.          tr2 = cc(1,2,k)+cc(1,3,k)
  14.          cr2 = cc(1,1,k)+taur*tr2
  15.          ch(1,k,1) = cc(1,1,k)+tr2
  16.          ti2 = cc(2,2,k)+cc(2,3,k)
  17.          ci2 = cc(2,1,k)+taur*ti2
  18.          ch(2,k,1) = cc(2,1,k)+ti2
  19.          cr3 = taui*(cc(1,2,k)-cc(1,3,k))
  20.          ci3 = taui*(cc(2,2,k)-cc(2,3,k))
  21.          ch(1,k,2) = cr2-ci3
  22.          ch(1,k,3) = cr2+ci3
  23.          ch(2,k,2) = ci2+cr3
  24.          ch(2,k,3) = ci2-cr3
  25.   101 continue
  26.       return
  27.   102 do 104 k=1,l1
  28.          do 103 i=2,ido,2
  29.             tr2 = cc(i-1,2,k)+cc(i-1,3,k)
  30.             cr2 = cc(i-1,1,k)+taur*tr2
  31.             ch(i-1,k,1) = cc(i-1,1,k)+tr2
  32.             ti2 = cc(i,2,k)+cc(i,3,k)
  33.             ci2 = cc(i,1,k)+taur*ti2
  34.             ch(i,k,1) = cc(i,1,k)+ti2
  35.             cr3 = taui*(cc(i-1,2,k)-cc(i-1,3,k))
  36.             ci3 = taui*(cc(i,2,k)-cc(i,3,k))
  37.             dr2 = cr2-ci3
  38.             dr3 = cr2+ci3
  39.             di2 = ci2+cr3
  40.             di3 = ci2-cr3
  41.             ch(i,k,2) = wa1(i-1)*di2+wa1(i)*dr2
  42.             ch(i-1,k,2) = wa1(i-1)*dr2-wa1(i)*di2
  43.             ch(i,k,3) = wa2(i-1)*di3+wa2(i)*dr3
  44.             ch(i-1,k,3) = wa2(i-1)*dr3-wa2(i)*di3
  45.   103    continue
  46.   104 continue
  47.       return
  48.       end
  49.