SPFFT1

The SPFFT1 routine performs multiple fast Fourier transforms
           between complex amplitudes in Fourier space and real values
           in cyclic physical space.
           Subprogram spfft1 initializes trigonometric data each call.
           use subprogram spfft to save time and initialize once.
           This version invokes the IBM ESSL FFT.

USAGE:    CALL SPFFT1(IMAX,INCW,INCG,KMAX,W,G,IDIR)

   INPUT ARGUMENT LIST:
      IMAX     - INTEGER NUMBER OF VALUES IN THE CYCLIC PHYSICAL SPACE
	         (SEE LIMITATIONS ON IMAX IN REMARKS BELOW.)
      INCW     - INTEGER FIRST DIMENSION OF THE COMPLEX AMPLITUDE ARRAY
        	 (INCW >= IMAX/2+1)
      INCG     - INTEGER FIRST DIMENSION OF THE REAL VALUE ARRAY
	         (INCG >= IMAX)
      KMAX     - INTEGER NUMBER OF TRANSFORMS TO PERFORM
      W        - COMPLEX(INCW,KMAX) COMPLEX AMPLITUDES IF IDIR>0
      G        - REAL(INCG,KMAX) REAL VALUES IF IDIR<0
      IDIR     - INTEGER DIRECTION FLAG
	         IDIR>0 TO TRANSFORM FROM FOURIER TO PHYSICAL SPACE
	         IDIR<0 TO TRANSFORM FROM PHYSICAL TO FOURIER SPACE

   OUTPUT ARGUMENT LIST:
      W        - COMPLEX(INCW,KMAX) COMPLEX AMPLITUDES IF IDIR<0
      G        - REAL(INCG,KMAX) REAL VALUES IF IDIR>0

 


  
SPLIB.tar
  
Library contains routines to be
   be used for a variety of spectral transform functions. (Fortran90) 

   Date posted: 2/23/2007