Glad to hear it! There’s now an issue open on MutableArithmetics.jl to add support for rationals, so hopefully this will be easier at some point in the future. Ideally at some point one would only need to add MutableArithmetic’s @rewrite macro on the line which updates A[j], although I’m not sure that can ever get as fast as reusing the buffers over the course of the loop as I did in my solution. On the other hand there might be other tricks that can be incorporated to speed it up; I don’t know :).