Short technical description of functions in the fft(3) package


"ft.c"
The entry-points:
	fft	- Forward Complex Fast Fourier Transform
	rft	- Reverse Complex Fast Fourier Transform

"fourier.c"
Recursive implementation of the Cooley-Tukey algorithm:
	Fourier	- top level call
	radix	- determine radix for a number of samples
	split	- split samples in groups, and recursively call Fourier
	join	- join (add) groups of samples into a new group

"complex.h"
Manipulation of complex numbers:
	COMPLEX	- type for complex numbers
	c_re	- real part of complex number
	c_im	- imaginary part of complex number
	c_add_mul - multiply and add complex numbers
	c_conj	- convert a complex number into its conjugate
	c_realdiv - divide a complex by a real number

"w.h"
W-factors:
	W	- give previously calculated W-factor

"w.c"
Computation of W-factors:
	W_factors - array of W-factors
	Nfactors - number of factors in W_factors
	W_init	- prepare W-factors array