Hello everyone, today I learned the fast Hartley transform and solved a problem with it. In my opinion, this algorithm is very similar to the FFT, but it does not use any complex numbers. So my question is — if this algorithm is easier to implement than the FFT, then why is the first one not as common as the Fourier transform?

And one more — if you have a better implementation (I think, it is easy), please share it in the comments.

Thanks