sfft1du,dfft1du(3F)					   sfft1du,dfft1du(3F)

NAME    [Toc]    [Back]

     dfft1du, sfft1du -	1D Real	to Complex Fast	Fourier	Transform.

FORTRAN	SPECIFICATION
     subroutine	DFFT1DU( job, n, sequence, inc,	workspace )
     integer		job, n,	inc
     double precision	sequence(*), workspace(*)

     subroutine	SFFT1DU( job, n, sequence, inc,	workspace )
     integer		job, n,	inc
     real		sequence(*), workspace(*)

C SPECIFICATION    [Toc]    [Back]

     int sfft1du ( int job, int	n, float *sequence,
		  int inc, float *workspace);

     int dfft1du ( int job, int	n, double *sequence,
		  int inc, double *workspace);

DESCRIPTION    [Toc]    [Back]

     DFFT1DU and SFFT1DU compute the 1 dimensional Fourier transform of	a real
     periodic sequence.

     NOTE: These routines are provided only for	compatibility with previous
     releases of complib.

PARAMETERS    [Toc]    [Back]

     JOB - INTEGER
     On	entry specifies	whether	to perform a forward or	backward Fast Fourier
     Transform:
	 JOB = -1,  forward FFT
	 JOB =	1,  backward FFT Unchanged on exit.

     N - INTEGER.    [Toc]    [Back]
     On	entry, N specifies the number of elements in the 1D FFT.  Unchanged on
     exit.

     SEQUENCE -	Array.
     Array of dimension	at least 2*( (N+2)/2 ).	On entry it contains the
     elements for the FFT.  On exit, SEQUENCE is overwritten by	the 1D
     transform.

     INC - INTEGER.    [Toc]    [Back]
     Increment between two consecutive elements	of the sequence.  Unchanged on
     exit.

     WORKSPACE - Array.    [Toc]    [Back]
     Array of dimension	at least N + 15.  On entry it contains the
     Sines/Cosines and factorization of	N.  WORKSPACE needs to be initialized



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sfft1du,dfft1du(3F)					   sfft1du,dfft1du(3F)



     by	a call to sfft1dui or dfft1dui.

SEE ALSO    [Toc]    [Back]

     o32fft


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