Mostly academic points to correct the record, but I feel like mratsim's linked "Fenwick Tree" uses up to 2x the cache memory of the trees of Fenwick 1993,1994,1995. So, maybe not quite even state of the art for the mid-1990s (depending on metrics/data sizes)?
Also, maybe not really even Fenwick Trees? The Yu2015 paper referenced in the code _very_ questionably re-brands what Wong 1980 had called simply "binary trees" as seemingly new but not "F+Trees" while removing the space optimization that was Fenwick94's contribution over Wong80. All quite weird. Don't get me wrong - that sampler is good code. Maybe not optimal, though.
