WALSH, a C++ 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.
WALSH is available in a C version and a C++ version and a FORTRAN90 version and a MATLAB version and a Python version.
HAAR, a C++ library which computes the Haar transform of data.
SFTPACK, a C++ library which implements the "slow" Fourier transform, intended as a teaching tool and comparison with the fast Fourier transform.
SINE_TRANSFORM, a C++ library which demonstrates some simple properties of the discrete sine transform.