scipy.fftpack
The package scipy.fftpack does two things: fast Fourier transforms, and differentiation and integration of periodic sequences.
Fast Fourier Transforms
The fft() function can be used by importing scipy, ie import scipy * However, other functions such as fft2 and the helper functions require the import of fftpack explicitly.
- fft(a)
performs an Fourier transform on the array a and returns a complex array
- ifft()
- Inverse of fft
- fftn()
- Multi-dimensional FFT
- ifftn()
- Inverse of fftn
- fft2()
- 2D FFT
- ifft2()
- Inverse of fft2
- rfft()
- FFT of real periodic sequences
- irfft()
- Inverse of rfft
Differential and pseudo-differential operators
Helper functions
The helper functions have to be imported explicitly to be able to use them. That is import scipy * is not enough, import scipy.fftpack is required
- fftshift()
- Shift zero-frequency component to the centre of the spectrum
- ifftshift()
- Inverse of fftshift
- dftfreq()
- rfftfreq()