Yeah, it’s easy when alpha is fixed. The complications — the exp() and ln() — come from updating the smoothed rate at varying intervals, whenever a request happ

Yeah, it’s easy when alpha is fixed. The complications — the exp() and ln() — come from updating the smoothed rate at varying intervals, whenever a request happens to arrive, so alpha has to be adjusted according to the interval to make sure the exponential decay happens at a fixed speed regardless of the interval.