Fast Hadamard and Walsh Transforms
$ luarocks install math-walshtransform
These routines implement fast Hadamard and Walsh Transforms
and their inverse transforms.
Also included are routines for converting a Hadamard to a
Walsh transform and vice versa, for calculating the Logical
Convolution of two lists, or the Logical Autocorrelation of
a list, and for calculating the Walsh Power Spectrum - in short,
almost everything you ever wanted to do with a Walsh Transform.