After fiddling around with various parameters in the entropy function and benchmarking the results, I decided that any benefits I might find were too small to warrant very much of my time looking for them. Besides, many of them produced negative values for the entropy, which, as I have previously alluded, is acceptable for a heuristic function, but not for the entropy calculation my program promises. I was more open to this discrepancy before, but the improvements I was seeing (if they actually were improvements) were not worth the change. Thus, I decided to write up a README, publish to crates.io, and call it a day. I may come back with more tweaks in the future, but for now, I think the performance is acceptable. (Nevertheless, you can find the data from all of my benchmarking trials in the repository.)