4 ms·
I found a bug in Algorithm D, the long division algorithm in Knuth's "The Art of Computer Programming". It was discussed on HN a couple of times https://news.yc
by nk_kolja 2mo ago
I found a bug in Algorithm D, the long division algorithm in Knuth's "The Art of Computer Programming". It was discussed on HN a couple of times https://news.ycombinator.com/item?id=26562819 https://news.ycombinator.com/item?id=26562819 as well as on other websites.
I sent a letter to Knuth and received a check and an annotated reply. The updated Theorem B, which was unchanged since 1969 is now dated 2026.
While searching for vulnerable implementations I also found a "bug" in llvm, so I expanded a bit on that too.
- jason_s 2mo agoCongratulations! Wow, you got a legendary $2.56 check....
- warmwaffles 2mo agoHopefully framed it and put it on the wall.
- WillAdams 2mo agoUnfortunately, one no longer gets physical checks, instead, one gets an account in The Bank of the Island of San Seriffe: https://www-cs-faculty.stanford.edu/~knuth/boss.html https://www-cs-faculty.stanford.edu/~knuth/boss.html (unfortunately, I have yet to find another typo since getting my $2.88 for _Digital Typography_)
- malisper 2mo agoYou still get a physical piece of paper that looks like a check; it's just not a valid check.
- bluGill 2mo agoClose enough. If I ever got such a check it would be professionally framed and hung on my wall. As would most people reading this.
- sandbach 2mo agoMost people reading this would be hung on your wall?
- philipallstar 2mo agoAfter being framed, of course. You need to have a justification.
- toast0 2mo agoI heard philipallstar and sandbach were doing treason. @bluGill, you owe me some money or this framing won't be professional. ;)
- bluGill 2mo agoWait, I thought I was going to frame you, but it turns out you're you're blackmailing me. I don't have to frame you anymore. I have evidence of a real crime.
- philipallstar 2mo agoThis is some very unprofessional framing.
- dhosek 2mo agoI have at least one Knuth check¹ from the days when they were actual checks, but to be honest, I’m not 100% sure where it (they?) are. I’m on the mailing list where potential TeX-related bugs appear and it’s crazy the level of detail people go to in looking for any remaining bugs in that software. ⸻ 1. I know at least one of these came from porting lesser-known utilities to VM/CMS. By that time, DEK already had adopted a practice of having his secretary print his emails and he’d hand-write a reply and you’d get it in the mail.
- actionfromafar 2mo agoBut but... that's all serif.
- brewmarche 1mo agoThere’s a funny explanation at the bottom: > It turns out that only 9 of the first 275 checks that I've sent out since the beginning of 2006 have actually been cashed. The others have apparently been cached. So this change in policy will probably not affect too many people. On the other hand, I don't like to renege on promises, so I shall do my best to find a suitable way to send money to anyone who really prefers legal tender.
- AndruLuvisi 2mo agoWow, congratulations on finding this most epic bug!
- nk_kolja 2mo agoThank you!