scfftm1dui,dzfftm1dui(3F) scfftm1dui,dzfftm1dui(3F)NAME
scfftm1dui, dzfftm1dui - initialize the coefficient array for real-to-
complex Multiple 1D FFT modules.
SYNOPSYS
FORTRAN SPECIFICATION
subroutine SCFFTM1DUI( n, coeff )
integer n
real coeff(n+15)
subroutine DZFFTM1DUI( n, coeff )
integer n
real*8 coeff(n+15)
C SPECIFICATION
#include <fft.h>
float *scfftm1dui( int n, float *coeff);
double *dzfftm1dui( int n, double *coeff);
DESCRIPTION
Initialize, the coefficient array which is used in the Multiple 1D FFT
modules. This array contains the different twiddle factors and the
factorization of N into prime numbers.
As the FFT modules scfftm1d or dzfftm1d only read the coeff array, it may
be reused as long as necessary once it has been initialized.
In C, if ptr is NULL, scfftm1dui or dzfftm1dui returns a pointer to an
allocated buffer.
SCFFTM1DUI should be used to initialize the coefficient array before any
call to SCFFTM1DU
DZFFTM1DUI should be used to initialize the coefficient array before any
call to DZFFTM1DU
PARAMETERS
N - Integer. Specifies the length of the 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.
Fortran :
real coeff(200+15)
call scfftm1dui( 200, coeff)
C :
#include <fft.h>
float *coeff;
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scfftm1dui,dzfftm1dui(3F) scfftm1dui,dzfftm1dui(3F)
coeff = scfftm1dui( 200, NULL);
SEE ALSO
fft, scfftm1du, dzfftm1du
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