walsh_transform, a Python code which implements versions of the Walsh and Haar transforms.
Note that the programs, as printed in the reference, had a few typographical errors. Several programs, in particular FHT and FRT, could not be made to perform as described in the text, and hence have been omitted.
The computer code and data files described and made available on this web page are distributed under the MIT license
walsh_transform is available in a C version and a C++ version and a Fortran90 version and a MATLAB version and an Octave version and a Python version.
sftpack, a Python code which implements the "slow" Fourier transform, intended as a teaching tool and comparison with the fast Fourier transform.
sine_transform, a Python code which demonstrates some simple properties of the discrete sine transform.