cc [ flag... ] file... lmlib [ library... ] #include <mlib.h> mlib_status mlib_SignalFFTW_4_S16_S16(mlib_s16 *dstr, mlib_s16 *dsti, const mlib_s16 *srcr, const mlib_s16 *srci, const mlib_s16 *window, mlib_s32 order, mlib_s32 *scale);
mlib_status mlib_SignalFFTW_4_S16C_S16C(mlib_s16 *dstc, const mlib_s16 *srcc,const mlib_s16 *window, mlib_s32 order, mlib_s32 *scale);
mlib_status mlib_SignalFFTW_4_S16C_S16(mlib_s16 *dstc, const mlib_s16 *srcr,const mlib_s16 *window, mlib_s32 order, mlib_s32 *scale);
mlib_status mlib_SignalFFTW_4_S16(mlib_s16 *srcdstr, mlib_s16 *srcdsti,const mlib_s16 *window, mlib_s32 order, mlib_s32 *scale);
mlib_status mlib_SignalFFTW_4_S16C(mlib_s16 *srcdstc, const mlib_s16 *window,mlib_s32 order, mlib_s32 *scale);
Each of the functions in this group performs Fast Fourier Transform with windowing (FFTW).
The FFTW functions use the following equation:
1 N1 dst[k] =  SUM {src[n] * window[n] * exp(j2*PI*n*k/N)} C1 n=0
and the IFFTW functions use the following equation:
1 N1 dst[n] =  SUM {src[k] * window[k] * exp(j2*PI*n*k/N)} C2 k=0
where
k = 0, 1, ..., (N  1) n = 0, 1, ..., (N  1) N = 2**order
The signal FFTW/IFFTW functions can be categorized into four groups according to the ScaleMode in the function names in the following form:
mlib_Signal[FFTWIFFTW]_ScaleMode_OutType_InType_OpMode() mlib_Signal[FFTWIFFTW]_ScaleMode_DataType_OpMode()
The scaling factors C1 and C2 used in the equations are defined as follows:
For functions with only real parts for the source signal, the imaginary parts are assumed to be all zero. For functions with only real parts for the destination signal, the imaginary parts are discarded. The functions with only one data type in their names perform the operation in place.
Each function takes some of the following arguments:
dstr
dsti
srcr
srci
dstc
srcc
srcdstr
srcdsti
srcdstc
window
order
scale
Each function returns MLIB_SUCCESS if successful. Otherwise it returns MLIB_FAILURE.
See attributes(5) for descriptions of the following attributes:

mlib_SignalFFTW_1(3MLIB), mlib_SignalFFTW_2(3MLIB), mlib_SignalFFTW_3(3MLIB), mlib_SignalIFFTW_1(3MLIB), mlib_SignalIFFTW_2(3MLIB), mlib_SignalIFFTW_3(3MLIB), mlib_SignalIFFTW_4(3MLIB), attributes(5)