May 23, 2026
Factorial Frenzy, Comment Chaos
Fast Factorial Algorithms
Math nerds found faster ways to do factorials, and the comments instantly got messy
TLDR: The page showcases several fast ways to calculate factorials, including one presented as the fastest known method. But the comments stole the spotlight, with readers arguing over missing explanations, demanding famous shortcuts, and joking that a compiler might save the article’s worst example.
A deeply math-heavy page about calculating factorials — those giant numbers made by multiplying 1 times 2 times 3 and so on — somehow turned into a mini comment-section soap opera. The site lays out a whole menu of ways to do it faster, from the simple-but-speedy SplitRecursive method to the allegedly king-of-the-hill PrimeSwing, plus a parallel version for multi-core computers. It even dunks on the classic schoolbook recursive version with a blunt "Just don't use it!" and yes, the crowd absolutely noticed the shade.
But the real action was in the replies, where readers split into camps almost immediately. One frustrated commenter said the page promised clever tricks but barely explained them, calling the learning experience "somewhat mediocre" before dropping the ultimate 2020s plot twist: they’d just ask ChatGPT to explain it instead. Another mini-drama erupted when someone demanded "No Stirling formula?" — basically asking why a famous shortcut for estimating huge factorials was missing. A fellow commenter rushed in with the receipts, pointing out there’s literally a separate approximations page, which gave the thread a classic "did you even click the link?" energy.
Then came the practical crowd. One person shrugged that if you really want speed, just use a cached map because factorials become absurdly huge so fast that most people won’t need many values anyway. And the funniest jab of all? A commenter wondering whether any compiler could rescue the article’s mocked "simple-minded" recursive code and secretly turn it into something smarter. In other words: the math was impressive, but the comments were a mix of nitpicking, backseat engineering, and dry nerd humor — exactly as the internet intended.
Key Points
- •The article identifies five notable factorial algorithms: SplitRecursive, PrimeSwing, Moessner's additive method, Poor Man's, and ParallelPrimeSwing.
- •PrimeSwing is described as the asymptotically fastest known algorithm for computing n! and depends on the prime factorization of swing numbers.
- •SplitRecursive is presented as a simple fast method and the fastest one listed that does not use prime factorization.
- •The article provides a divide-and-conquer BigInt sample implementation for users who do not need maximum performance and warns against the naive recursive factorial implementation.
- •Additional linked resources include implementations in multiple languages, benchmark claims using MPIR 2.6, and related material on approximations, gamma functions, and Hadamard's gamma function.