sdfft1du(3F)

NAME
     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
     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
     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
     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.
     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.
     Increment between two consecutive elements of the sequence.  Unchanged on
     exit.

     WORKSPACE - Array.
     Array of dimension at least N + 15.  On entry it contains the
     Sines/Cosines and factorization of N.  WORKSPACE needs to be initialized
     by a call to sfft1dui or dfft1dui.


SEE ALSO
     o32fft