fxt

fxt is a library package (coming as C++ source code) containing code various
algorithms for:
- Fast Fourier Transform (FFT) incl. real-vlued,
- multidimensional and weighted variants.
- Fast Hartley Transform (FHT)
- Number Theoretic Transform (NTT), Fast Walsh Transform.
- Convolution (cyclic, linear and weighted),
- correlation and power spectrum.
- Fast Haar Transform, Fast Wavelet Transform
- Mass storage convolution and fast multiplication routines.
- Sine- and cosine transform (DCT, DST), Fast Z-Transform (FZT)