*
* $Id: rft.F,v 1.1.1.1 1996/04/01 15:02:22 mclareni Exp $
*
* $Log: rft.F,v $
* Revision 1.1.1.1  1996/04/01 15:02:22  mclareni
* Mathlib gen
*
*
#include "gen/pilot.h"
      SUBROUTINE RFT (MM, X, IX, Y, IY, MODE)
C     EXECUTE REAL FAST FOURIER TRANSFORM.
C
C     INPUT     ... (X(I*IX+1), I = 0, N)
C     OUTPUT    ... (Y(I*IY+1), I = 0, N)
C     MM        ... INTEGER, SUCH THAT N = 2 ** MM.
C     MODE = 1  ... ANALYSIS OF A REAL PERIODIC FUNCTION.
C     MODE = 2  ... ANALYSIS OF A REAL EVEN FUNCTION.
C     MODE = 3  ... ANALYSIS OF A REAL ODD FUNCTION.
C     MODE = 4  ... SYNTHESIS OF A REAL PERIODIC FUNCTION.
C     MODE = 5  ... SYNTHESIS OF A REAL EVEN FUNCTION.
C     MODE = 6  ... SYNTHESIS OF A REAL ODD FUNCTION.
C
      REAL X(128), Y(128)
      COMMON /D700DT/ N, N2, N4, M, F, RTTWO
      COMMON /FWORK/ W(321)
C
      GO TO (10, 20, 30, 40, 20, 30), MODE
C
C     ANALYSIS OF A REAL PERIODIC FUNCTION.
   10 CALL RPA (MM, X, IX, Y, IY)
      RETURN
C
C     ANALYSIS OR SYNTHESIS OF A REAL EVEN FUNCTION.
   20 CALL RCA (MM, X, IX, Y, IY)
      RETURN
C
C     ANALYSIS OR SYNTHESIS OF A REAL ODD FUNCTION.
   30 CALL RSA (MM, X, IX, Y, IY)
      RETURN
C
C     SYNTHESIS OF A REAL PERIODIC FUNCTION.
   40 CALL RPS (MM, X, IX, Y, IY)
      RETURN
      END