The FFT module has been pushed into the eigen2 repository.
It currently lives in "unsupported". The interface is still somewhat fluid.
Also of interest is the unsupported/Complex class.
Comments & code changes welcome.
Mark,
Today I had a need for a quick FFT calculation in a project that was already using Eigen, and I came across your post about the FFT module. I was able to get the module from the repository and slap it on top of a recent Eigen release, and it just worked. THANK YOU so much for doing this, it helped me out a lot.
Best,
Stjepan