FFTW is a collection of fast C routines for computing the Discrete Fourier Transform in one or more dimensions. It includes complex, real, and parallel transforms, and can handle arbitrary array sizes efficiently. The FFTW Add-On consists of a DLL incorporating the FFTW routines, plus supporting J scripts and labs. FFTW and the FFTW package are distributed under the terms of the GNU General Public License. For more information on GNU, see the GNU web page.
FFTW is only available under Windows.
Download fftw.zip for J6, or fftw504.zip for J504 and unzip it in the J addons directory. After it is installed, run lab Fast Fourier Transform to learn about this powerful new addition to J.
For more information on FFTW, see the FFTW web page. Download fftw-2_0_1.zip (1.2MB) for the DLL source.