CFFT2(3F)							     CFFT2(3F)

NAME    [Toc]    [Back]

     CFFT2 - Calculate a complex-to-complex Fourier synthesis/analysis.

DESCRIPTION    [Toc]    [Back]

     A subroutine that calculates a Fourier synthesis if the sign of IX	is
     negative and a Fourier analysis if	the sign of IX is positive.

      Call from	FORTRAN:

	    CALL CFFT2(init,ix,n,x,work,y)

	  init	<>0  Generates sine and	cosine tables in WORK
		= 0  Calculates	Fourier	transforms using sine and
		   cosine tables of previous call.
	  ix	> 0  Calculates	Fourier	analysis
		< 0  Calculates	Fourier	synthesis.
	  n	Size of	Fourier	transform; 2**m	where 2<=m for the
		CRAY-1.
	  x	Input vector.  Vector of n complex values.
	  work	Working	storage.  Vector of (5/2)n complex values.
	  y	Result vector.	Vector of n complex values.

     For equations and other additional	information, see the CRAY-1 Computer
     Systems - Library Reference Manual, SR-0014, pages	4-51 to	4-52.


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