cscalm1d,zscalm1d(3F)					 cscalm1d,zscalm1d(3F)

NAME    [Toc]    [Back]

     cscalm1d, zscalm1d	- scales Multiple 1D complex sequences.

SYNOPSYS    [Toc]    [Back]

     Fortran :
     subroutine	cscalm1d( n, p,	alpha, array, inc, lda)
	  integer	     n,	p, inc,	lda
	  real		     alpha
	  complex	     array(lda,p)
     subroutine	zscalm1d( sign,	n, p, array, inc, lda)
	  integer	     n,	p, inc,	lda
	  real*8	     alpha
	  double complex     array(lda,p)

     C :
     #include <fft.h>
     int cscalm1d ( int	n, int p, float	alpha, complex *array,
	       int inc,	int lda);
     int zscalm1d ( int	n, int p, double alpha,	zomplex	*array,
	       int inc,	int lda);

DESCRIPTION    [Toc]    [Back]

     cscalm1d and zscalm1d scale the P complex sequences of N samples each.
     The Fourier Transforms are	not normalized so the succession DirectInverse
 transform scales the input	data by	a factor equal to the size of
     the transform.  cscalm1d or zscalm1d are used to scale back the result.

PARAMETERS    [Toc]    [Back]

     N - Integer, the number of	samples	in each	sequence.
     Unchanged on exit.

     P - Integer, the number of	sequences.  Unchanged on exit.

     Alpha - scaling floating point value.  Unchanged on exit.

     ARRAY - Array containing the samples of the sequence to be	scaled (in
     place).

     INC - Integer, increment between two consecutive elements of a sequence.
     Unchanged on exit.

     LDA - Integer, leading dimension: increment between the first samples of
     two consecutive sequences.	 Unchanged on exit.


Example	of Calling Sequence
     Working on	64 sequences of	1024 complex values each.  We successively
     apply a Direct Fourier Transform, an Inverse Fourier Trasnform and
     finally scale back	the result by a	factor 1/N (1/1024.)-
     This sequence DirectFFT-InverseFFT-Scaling	is equivalent to the identity
     operator and the final sequence should be equal (with round-off



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cscalm1d,zscalm1d(3F)					 cscalm1d,zscalm1d(3F)



     precision)	to the initial sequence.
     Elements of each sequence are stored with increment (stride) 1, and the
     offset between the	first element of two succesive sequence	(leading
     dimension)	is 2049.
     Fortran :
	  complex array(0:2049-1,0:64-1), coeff(1024+15)
	  call cfftm1di( 1024, coeff)
	  call cfftm1d(	-1, 1024, 64, array, 1,	2049, coeff)
	  call cfftm1d(	 1, 1024, 64, array, 1,	2049, coeff)
	  call cscalm1d(1024,64,(1./real(1024)),array,1,2049)

     C :
	  #include <fft.h>
	  complex array[64*2049], *coeff;
	  coeff	= cfftm1di( 1024, NULL);
	  cfftm1d( -1, 1024, 64, array,	1, 2049, coeff);
	  cfftm1d(  1, 1024, 64, array,	1, 2049, coeff);
	  cscalm1d( 1024, 64, 1./(float)1024, array, 1,	2049);

     NOTE_1 : The Direct and Inverse transforms	should use opposite signs -
     Which one is used (+1 or -1) for Direct transform is just a matter	of
     convention
     NOTE_2 : The Fourier Transforms are not normalized	so the succession
     Direct-Inverse transform scales the input data by a factor	equal to the
     size of the transform.

SEE ALSO    [Toc]    [Back]

     fft, cfftm1di, zfftm1di, cfftm1d, zfftm1d,	cprodm1d, zprodm1d


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