12 Real optimized version can save about 45% cpu time vs. complex fft of a real seq.
18 typedef struct kiss_fftr_state
*kiss_fftr_cfg
;
21 kiss_fftr_cfg
kiss_fftr_alloc(int nfft
,int inverse_fft
,void * mem
, size_t * lenmem
);
25 If you don't care to allocate space, use mem = lenmem = NULL
29 void kiss_fftr(kiss_fftr_cfg cfg
,const kiss_fft_scalar
*timedata
,kiss_fft_cpx
*freqdata
);
31 input timedata has nfft scalar points
32 output freqdata has nfft/2+1 complex points
35 void kiss_fftr2(kiss_fftr_cfg st
,const kiss_fft_scalar
*timedata
,kiss_fft_scalar
*freqdata
);
37 void kiss_fftri(kiss_fftr_cfg cfg
,const kiss_fft_cpx
*freqdata
,kiss_fft_scalar
*timedata
);
39 void kiss_fftri2(kiss_fftr_cfg st
,const kiss_fft_scalar
*freqdata
, kiss_fft_scalar
*timedata
);
42 input freqdata has nfft/2+1 complex points
43 output timedata has nfft scalar points
46 #define kiss_fftr_free speex_free