kiss_fft.c File Reference

KISS FFT, taken from: https://github.com/mborgerding/kissfft. More...

#include "_kiss_fft_guts.h"

Go to the source code of this file.

Functions
static void	kf_bfly2 (kiss_fft_cpx *Fout, const size_t fstride, const kiss_fft_cfg st, int m)
static void	kf_bfly4 (kiss_fft_cpx *Fout, const size_t fstride, const kiss_fft_cfg st, const size_t m)
static void	kf_bfly3 (kiss_fft_cpx *Fout, const size_t fstride, const kiss_fft_cfg st, size_t m)
static void	kf_bfly5 (kiss_fft_cpx *Fout, const size_t fstride, const kiss_fft_cfg st, int m)
static void	kf_bfly_generic (kiss_fft_cpx *Fout, const size_t fstride, const kiss_fft_cfg st, int m, int p)
static void	kf_work (kiss_fft_cpx *Fout, const kiss_fft_cpx *f, const size_t fstride, int in_stride, int *factors, const kiss_fft_cfg st)
static void	kf_factor (int n, int *facbuf)
kiss_fft_cfg	kiss_fft_alloc (int nfft, int inverse_fft, void *mem, size_t *lenmem)
	kiss_fft_alloc
void	kiss_fft_stride (kiss_fft_cfg st, const kiss_fft_cpx *fin, kiss_fft_cpx *fout, int in_stride)
	A more generic version of the above function.
void	kiss_fft (kiss_fft_cfg cfg, const kiss_fft_cpx *fin, kiss_fft_cpx *fout)
	kiss_fft(cfg,in_out_buf)
void	kiss_fft_cleanup (void)
	Cleans up some memory that gets managed internally.
int	kiss_fft_next_fast_size (int n)
	Returns the smallest integer k, such that k>=n and k has only "fast" factors (2,3,5)

Detailed Description

KISS FFT, taken from: https://github.com/mborgerding/kissfft.

Author

Mark Borgerding

License

BSD 3-Clause

Definition in file kiss_fft.c.

Function Documentation

kf_bfly2()

static void kf_bfly2 ( kiss_fft_cpx * Fout, const size_t fstride, const kiss_fft_cfg st, int m )

static

Definition at line 22 of file kiss_fft.c.

kf_bfly3()

static void kf_bfly3 ( kiss_fft_cpx * Fout, const size_t fstride, const kiss_fft_cfg st, size_t m )

static

Definition at line 93 of file kiss_fft.c.

kf_bfly4()

static void kf_bfly4 ( kiss_fft_cpx * Fout, const size_t fstride, const kiss_fft_cfg st, const size_t m )

static

Definition at line 45 of file kiss_fft.c.

kf_bfly5()

static void kf_bfly5 ( kiss_fft_cpx * Fout, const size_t fstride, const kiss_fft_cfg st, int m )

static

Definition at line 137 of file kiss_fft.c.

kf_bfly_generic()

static void kf_bfly_generic ( kiss_fft_cpx * Fout, const size_t fstride, const kiss_fft_cfg st, int m, int p )

static

Definition at line 199 of file kiss_fft.c.

kf_factor()

static void kf_factor ( int n, int * facbuf )

static

Definition at line 310 of file kiss_fft.c.

kf_work()

static void kf_work ( kiss_fft_cpx * Fout, const kiss_fft_cpx * f, const size_t fstride, int in_stride, int * factors, const kiss_fft_cfg st )

static

Definition at line 239 of file kiss_fft.c.

kiss_fft()

void kiss_fft	(	kiss_fft_cfg	cfg,
		const kiss_fft_cpx *	fin,
		kiss_fft_cpx *	fout )

kiss_fft(cfg,in_out_buf)

Perform an FFT on a complex input buffer. for a forward FFT, fin should be f[0] , f[1] , ... ,f[nfft-1] fout will be F[0] , F[1] , ... ,F[nfft-1] Note that each element is complex and can be accessed like f[k].r and f[k].i

Definition at line 386 of file kiss_fft.c.

kiss_fft_alloc()

kiss_fft_cfg kiss_fft_alloc	(	int	nfft,
		int	inverse_fft,
		void *	mem,
		size_t *	lenmem )

kiss_fft_alloc

Initialize a FFT (or IFFT) algorithm's cfg/state buffer.

typical usage: kiss_fft_cfg mycfg=kiss_fft_alloc(1024,0,NULL,NULL);

The return value from fft_alloc is a cfg buffer used internally by the fft routine or NULL.

If lenmem is NULL, then kiss_fft_alloc will allocate a cfg buffer using malloc. The returned value should be free()d when done to avoid memory leaks.

The state can be placed in a user supplied buffer 'mem': If lenmem is not NULL and mem is not NULL and *lenmem is large enough, then the function places the cfg in mem and the size used in *lenmem and returns mem.

If lenmem is not NULL and ( mem is NULL or *lenmem is not large enough), then the function returns NULL and places the minimum cfg buffer size in *lenmem.

Definition at line 340 of file kiss_fft.c.

kiss_fft_cleanup()

void kiss_fft_cleanup

(

void

)

Cleans up some memory that gets managed internally.

Not necessary to call, but it might clean up your compiler output to call this before you exit.

Definition at line 392 of file kiss_fft.c.

kiss_fft_next_fast_size()

int kiss_fft_next_fast_size

(

int

n

)

Returns the smallest integer k, such that k>=n and k has only "fast" factors (2,3,5)

Definition at line 397 of file kiss_fft.c.

kiss_fft_stride()

void kiss_fft_stride	(	kiss_fft_cfg	cfg,
		const kiss_fft_cpx *	fin,
		kiss_fft_cpx *	fout,
		int	fin_stride )

A more generic version of the above function.

It reads its input from every Nth sample.

Definition at line 372 of file kiss_fft.c.