CTITLERCFFT2 -- REAL-TO-COMPLEX FFT                                     00010002
C***********************************************************************
C                 COPYRIGHT ATLANTIC RICHFIELD COMPANY 1991            *
C***********************************************************************
CA    AUTHOR        STU NELAN                                           00020002
CA    DESIGNER      STU NELAN                                           00030002
CA    LANGUAGE      FORTRAN                                             00040002
CA    SYSTEM        IBM (SEE CRAY SYSTEM LIBRARY)                       00050002
CA    WRITTEN       02-19-86                                            00060002
C     REVISED       XX-XX-XX III.  ...                                  00070002
CA                                                                      00080002
CA                                                                      00090002
CA    CALL RCFFT2 (INIT, IX, N, X, WORK, Y)                             00100002
CA         INPUT   INIT = INITIALIZATION SWITCH                     I4  00110002
CA         INPUT     IX = FFT SWITCH                                I4  00120002
CA         INPUT      N = SIZE OF FFT                               I4  00130002
CA         INPUT      X = INPUT VECTOR OF LENGTH N                  R4  00140002
CA         WORK    WORK = WORK ARRAY                                R4  00150002
CA         OUTPUT     Y = RESULT VECTOR OF LENGTH (N/2)+1 COMPLEX   C4  00160002
CA                                                                      00170002
CA                                                                      00180002
CA       RCFFT2 SIMULATES THE CRAY RCFFT2 ROUTINE.                      00190002
CAEND                                                                   00200002
      SUBROUTINE RCFFT2 (INIT, IX, N, X, WORK, Y)                       00210002
C                                                                       00220002
      REAL  WORK (1)                                                    00230002
      REAL  X    (1)                                                    00240002
      REAL  Y    (1)                                                    00250002
C                                                                       00260002
      IF (INIT .NE. 0) GO TO                                        50  00270002
C                                                                       00280002
      CALL ARMVE (X, Y, N)                                              00290002
      CALL S1FMAG (N, MAG, LFOUR)                                       00300002
C                                                                       00310002
      CALL S2DFT2 (MAG, Y,                                        *100) 00320002
C                                                                       00330002
      SCALE = SQRT(N*2.0)                                               00340002
      NP2 = N + 2                                                       00350002
      DO 10 I = 1, NP2                                                  00360002
   10 Y(I) = Y(I) * SCALE                                               00370002
C                                                                       00380002
      IF (IX .LT. 0) GO TO                                          50  00390002
      DO 30 I = 2, NP2, 2                                               00400002
   30 Y(I) = -Y(I)                                                      00410002
C                                                                       00420002
   50 RETURN                                                            00430002
C                                                                       00440002
  100 CALL XDUMPX                                                       00450002
      GO TO                                                         50  00460002
C                                                                       00470002
      END                                                               00480002