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A pythonic python wrapper around FFTW



pyFFTW is a pythonic wrapper around FFTW 3, the speedy FFT library. The ultimate aim is to present a unified interface for all the possible transforms that FFTW can perform.

Both the complex DFT and the real DFT are supported, as well as on arbitrary axes of abitrary shaped and strided arrays, which makes it almost feature equivalent to standard and real FFT functions of numpy.fft (indeed, it supports the clongdouble dtype which numpy.fft does not).

Wisdom import and export now works fairly reliably.

Operating FFTW in multithreaded mode is supported.

pyFFTW implements the numpy and scipy fft interfaces in order for users to take advantage of the speed of FFTW with minimal code modifications.

A comprehensive unittest suite can be found with the source on the github repository or with the source distribution on PyPI.

The documentation can be found on github pages, the source is on github and the python package index page is here.

Requirements (i.e. what it was designed for)

  • Python 2.7 or greater (Python 3 is supported)
  • Numpy 1.6
  • FFTW 3.3 or higher (lower versions may work)
  • Cython 0.15 or higher (though the source release on PyPI loses this dependency)

(install these as much as possible with your preferred package manager).


We recommend not building from github, but using the release on the python package index with tools such as easy_install or pip:

pip install pyfftw


easy_install pyfftw

Installers are on the PyPI page for both 32- and 64-bit Windows, which include all the necessary DLLs.

With FFTW installed, the PyPI release should install fine on Linux and Mac OSX. It doesn't mean it won't work anywhere else, just we don't have any information on it.

Read on if you do want to build from source...


To build in place:

python build_ext --inplace

That cythons the python extension and builds it into a shared library which is placed in pyfftw/. The directory can then be treated as a python package.

After you've run with cython available, you then have a normal C extension in the pyfftw directory. Further building does not depend on cython (as long as the .c file remains).

For more ways of building and installing, see the distutils documentation

Platform specific build info


To build for windows from source, download the fftw dlls for your system and the header file from here (they're in a zip file) and place them in the pyfftw directory. The files are libfftw3-3.dll, libfftw3l-3.dll, libfftw3f-3.dll. If you're using a version of FFTW other than 3.3, it may be necessary to copy fftw3.h into include\win.

The builds on PyPI use mingw for the 32-bit release and the Windows SDK C++ compiler for the 64-bit release. The scripts should handle this automatically. If you want to compile for 64-bit Windows, you have to use the MS Visual C++ compiler. Set up your environment as described here and then run with the version of python you wish to target and a suitable build command.

For using the MS Visual C++ compiler, you'll need to create a set of suitable .lib files as described on the FFTW page.


It has been suggested that FFTW should be installed from macports.

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