The default complex <-> complex FFT. More...

#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include <string.h>

Data Structures
struct	kiss_fft_cpx
	Complex data type used by kissFFT. More...

Macros
#define	KISS_FFT_MALLOC malloc

#define	KISS_FFT_FREE free

#define	kiss_fft_scalar float

#define	kiss_fft_free KISS_FFT_FREE

#define	kiss_fftr_next_fast_size_real(n) (kiss_fft_next_fast_size( ((n)+1)>>1)<<1)

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

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_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.

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

The default complex <-> complex FFT.

Taken from: https://github.com/mborgerding/kissfft

Author: Mark Borgerding

License: BSD 3-Clause

Definition in file kiss_fft.h.

Macro Definition Documentation

◆ KISS_FFT_FREE

#define KISS_FFT_FREE free

Definition at line 59 of file kiss_fft.h.

◆ kiss_fft_free

#define kiss_fft_free KISS_FFT_FREE

Definition at line 129 of file kiss_fft.h.

◆ KISS_FFT_MALLOC

#define KISS_FFT_MALLOC malloc

Definition at line 56 of file kiss_fft.h.

◆ kiss_fft_scalar

#define kiss_fft_scalar float

Definition at line 74 of file kiss_fft.h.

◆ kiss_fftr_next_fast_size_real

#define kiss_fftr_next_fast_size_real ( n ) (kiss_fft_next_fast_size( ((n)+1)>>1)<<1)

Definition at line 144 of file kiss_fft.h.

Function Documentation

◆ 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.

Data Structures

Macros

Functions