FFTX is the exascale follow-on to the FFTW open-source discrete FFT package for executing the Fast Fourier Transform as well as higher-level operations composed of linear operations combined with discrete Fourier transforms. Though backward compatible with FFTW, this is an entirely new work developed as a cooperative effort between Lawrence Berkeley National Laboratory, Carnegie Mellon University, and SpiralGen, Inc.
See our page with FFTX references: http://www.spiral.net/software/fftx.html
FFTX Project documentation: https://spiral-software.github.io/fftx/
See our github site for installation: https://github.com/spiral-software/fftx