CTITLECFFT2  -- COMPLEX-TO-COMPLEX FFT                                  00010001
C***********************************************************************
C                 COPYRIGHT ATLANTIC RICHFIELD COMPANY 1991            *
C***********************************************************************
CA    AUTHOR        STU NELAN                                           00020001
CA    DESIGNER      STU NELAN                                           00030001
CA    LANGUAGE      FORTRAN                                             00040001
CA    SYSTEM        IBM (SEE CRAY SYSTEM LIBRARY)                       00050001
CA    WRITTEN       09-02-87                                            00060001
C     REVISED       MM-DD-YY III.  ...                                  00070001
CA                                                                      00080001
CA                                                                      00090001
CA    CALL CFFT2 (INIT, IX, N, X, WORK, Y)                              00100001
CA         INPUT   INIT = INITIALIZATION SWITCH                     I4  00110001
CA                        0 = GENERATES SIN/COS TABLES IN WORK          00120001
CA                        0 <> CALCULATES FOURIER TRANSFORMS            00130001
CA         INPUT     IX = FFT SWITCH                                I4  00140001
CA                        >0 CALCULATES FOURIER ANALYSIS                00150001
CA                        <0 CALCULATES FOURIER SYNTHESIS               00160001
CA         INPUT      N = SIZE OF FFT                               I4  00170001
CA         INPUT      X = INPUT VECTOR OF LENGTH N                  R4  00180001
CA         WORK    WORK = WORK ARRAY                                R4  00190001
CA         OUTPUT     Y = RESULT VECTOR OF LENGTH (N/2)+1 COMPLEX   C4  00200001
CA                                                                      00210001
CA                                                                      00220001
CA       CFFT2 SIMULATES THE CRAY CFFT2 ROUTINE.                        00230001
CAEND                                                                   00240001
      SUBROUTINE CFFT2 (INIT, IX, N, X, WORK, Y)                        00250001
C                                                                       00260001
      REAL  WORK (1)                                                    00270001
      REAL  X    (1)                                                    00280001
      REAL  Y    (1)                                                    00290001
C                                                                       00300001
      IF (INIT .NE. 0) GO TO                                        50  00310001
C                                                                       00320001
      NT2 = N * 2                                                       00330001
      CALL ARMVE (X, Y, NT2)                                            00340001
      CALL S1FMAG (N, MAG, LFOUR)                                       00350001
C                                                                       00360001
      IF (IX .GT. 0) CALL S2FFI2 (MAG, Y,                         *100) 00370001
C                                                                       00380001
      IF (IX .LT. 0) CALL S2FFT2 (MAG, Y,                         *100) 00390001
C                                                                       00400001
      SCALE = SQRT(N*1.0)                                               00410001
      DO 10 I = 1, NT2                                                  00420001
   10 Y(I) = Y(I) * SCALE                                               00430001
C                                                                       00440001
   50 RETURN                                                            00450001
C                                                                       00460001
  100 CALL XDUMPX                                                       00470001
      GO TO                                                         50  00480001
C                                                                       00490001
      END                                                               00500001