FFT :: Fast Fourier Transform

• Tutorial
  • FFT @wikipedia
  • The Scientist and Engineer's Guide to Digital Signal Processing
  • Mathematics of the Discrete Fourier Transforms
  • Picture Book of Fourier Transforms
  • The FFT Demystified
• Source Code
  • FFTReal :: C++ and Delphi class for computing FFT and IFFT on vector and real numbers
  • NFFT :: C subroutines library for computing non-equispaced DFT
  • dgbfft :: Extremely fast for floating point FFT
  • FFT codes and related stuffs
  • FFTPACK from netlib
  • vfftpack from netlib
  • FFTW Homepage
  • benchFFT :: To benchmark FFT softwares
  • C-source for a very fast arbitary N FFT routine
  • ccSHT :: A fast parallel spherical haramonic transform