Scilab functions
fftw_flags - set computation method of fast fourier transform of the fftw function
fftw_inplace - set if transform is realized in place
fftw_norm - set if inverse transform of the fftw function is normalized
fftw - fast fourier transform that use fftw library
freefftw_plan - free all the planners stored in memory
pushfftw_plan - push the last used fftw planner in memory