scfft2dui,dzfft2dui(3F)				       scfft2dui,dzfft2dui(3F)

NAME    [Toc]    [Back]

     scfft2dui,	dzfft2dui - initialize the coefficient array for real-tocomplex
 2D	FFT modules.

SYNOPSYS    [Toc]    [Back]

     FORTRAN SPECIFICATION
     subroutine	SCFFT2DUI( n1, n2, coeff )
     integer		      n1, n2
     real	    coeff((n1+15) + 2*(n2+15))

     subroutine	DZFFT2DUI( n1, n2, coeff )
     integer		      n1, n2
     real*8		 coeff((n1+15) + 2*(n2+15))

     C SPECIFICATION
     #include <fft.h>
     float *scfft2dui( int n1, int n2, float *coeff);

     double *dzfft2dui(	int n1,	int n2,	double *coeff);

DESCRIPTION    [Toc]    [Back]

     Initialize, the coefficient array which is	used in	the 2D FFT modules.
     This array	contains the different twiddle factors and the factorization
     of	N1 and N2 into prime numbers.
     As	the FFT	modules	scfft2d	or dzfft2d only	read the coeff array, it may
     be	reused as many times as	necessary once it has been initialized.

     In	C, if ptr is NULL, scfft2dui or	dzfft2dui returns a pointer to an
     allocated buffer.

     SCFFT2DUI should be used to initialize the	coefficient array before any
     call to SCFFT2DU
     DZFFT2DUI should be used to initialize the	coefficient array before any
     call to DZFFT2DU

PARAMETERS    [Toc]    [Back]

     N1	- Integer. Specifies the size of the first dimension of	the 2D
     sequence to be transformed.  Unchanged on exit.

     N2	- Integer. Specifies the size of the second dimension of the 2D
     sequence to be transformed.  Unchanged on exit.

     COEFF - Array (C or Fortran) or NULL pointer(C).

Example	of Calling Sequence
     Initializing a coefficient	array for real-to-complex FFTs of size 200 x
     300.

     Fortran :
	  real coeff((200+15)+2*(300+15))
	  call scfft2dui( 200, 300, coeff)



									Page 1






scfft2dui,dzfft2dui(3F)				       scfft2dui,dzfft2dui(3F)



     C :
	  #include <fft.h>
	  float	*coeff;
	  coeff	= scfft2dui( 200, 300, NULL);

SEE ALSO    [Toc]    [Back]

	  fft, scfft2du, dzfft2du


									PPPPaaaaggggeeee 2222