8 ms·
Discovering errors in Donald Knuth's TAOCP
- WillAdams 2y agoNice! When I reported an error and a point of improvement in _Digital Typography_ the address was printed and glued on, not hand-written, which somewhat detracts from the display of the check/envelope. Need to find another error so I can get an account....
- dmoy 2y agoThis makes me feel less bad about also not being able to figure out my printer's address printing function. Like I know it is capable. I know how to set up the hand feed for it (and I successfully do that for thicker paper). And ostensibly I know the right dimensions and how to line it up in a PDF. But then it's just failure after failure, and I go back to cut and paste or handwrite.
- WillAdams 2y agoReally miss poste.app on my NeXT Cube, which was a small app/service which did nothing but print a selected address onto a hand-fed envelope.
- nwellnhof 2y agoThe inventor of the bug bounty.
- jgrahamc 2y agoI have a Knuth cheque from back when he sent out real cheques. Or at least I did; for some reason I decided that cashing it was a good idea and so I have his note back to me and a photocopy of the actual cheque.
- belter 2y agoWhat error did you find?
- secondcoming 2y agoAren't the cheques for $2.56?
- deleted 2y ago[deleted]
- cinntaile 2y agolol I'm a bit curious about the thought process that led you to decide you wanted to cash it.
- tkhattra 2y agoI have one for $7.68 ($2.56*3). Alas, it was for some minor typos and grammatical errors in SPOCS [1], not "real" math errors in TAOCP. Never plan on cashing it in though. And I can't remember where I stashed it, so there's that too... :) [1] https://www-cs-faculty.stanford.edu/~knuth/cs.html https://www-cs-faculty.stanford.edu/~knuth/cs.html
- zabzonk 2y agoA long while back I wrote an answer on Stack Overflow to a question that asked "How to read TAOCP?" my answer looked something like this: - don't read them - get all the books, put them in a bin bag and shake vigorously with some lumps of coal, to give them that "used" look - go through the books, underline things at random and make notes (also at random) in the margin such as "how true", or even better "wrong!" - put books on shelf in office - never look at them again This has worked for me, though I must admit that Searching & Sorting and stuff about random numbers are pretty good. I got my copies free from Addison Wesley for doing some book reviews for them - not reviewing Knuth, needless to say!
- WillAdams 2y agoI have worked with two programmers who had well-thumbed copies of TAoCP on their shelves which each had actually read (one was the only other person I've met outside of a TeX conference who had a reward check) --- to this day, I've not worked with better devs.
- dhosek 2y agoAh nothing like a DEK post to pull out the old TeX folks on HN.
- wglb 2y agoWhen I bought the first volume in about 1969, I vowed to read that one, and then each one that followed. However, that is yet to come to pass. However, when we at Mark Williams Company writing the floating point routines for the C compiler (https://winworldpc.com/product/mark-williams-letsc/3x https://winworldpc.com/product/mark-williams-letsc/3x), we were heavily reading Chapter 4, particularly on long division. Also did spend some time in the Random Number generation chapter. An interesting difference between my 1965 version and the ones published today is that long multi-page foldout in Sorting and Searching showing tape-based merge sort is no longer part of the book.
- kragen 2y agoHey, I have a question about the Mark Williams Company. I understand it was founded by Aaron Swartz's father. Did he work on the programming? Did Aaron spend time around the office? I'm curious how Aaron first got involved in programming, which I think was probably long after the company.
- nickdrozd 2y agoGreat post. Some general takeaways for people who want Knuth checks: 1. You are unlikely to find errors in the algorithms themselves, especially if they've been officially published. You might find some infelicities, but these are not counted as full errors. For example, the author here found some confusing-but-not-wrong comments about local variables and unused registers. These are counted as "suggestions" (worth 0x20¢) rather than "errors" (worth 0x$1.00). 2. Knuth is pretty generous with credit -- if your suggestion leads him to find an error, you get credit for the error. The author here said that some defined variables went unused. Knuth pointed out that those variables were in fact used in an exercise. However, in looking this up he noticed a variable-related error in that exercise. Author is credited with 0x$1.00! 3. Exercises are more likely to contain errors and infelicities than the main text. And there are an awful lot of exercises. 4. Knuth includes a whole bunch of stuff in his books that is not related to CS. Lots of weird trivia and references. This stuff is more likely to be wrong than the main text. For example, Knuth mentions "icosahedral objects inscribed with Greek letters" and includes a reference to an article in the Bulletin de l’Institut français du Caire. But the author points out that the article is actually in the Bulletin de l’Institut français d’archéologie orientale. Whoops! 0x$1.00 for you!
- Tomte 2y agoDon't make assumptions about what parts must have been combed through so much that there is no chance of finding annerror. I found one and got my cheque on page Arabic one in one of his books. Paragraph one. First sentence. The very first word.
- eigenvalue 2y agoWas it the word “the” instead of “a”? Trying to think what else it could even be.
- svat 2y agohttps://news.ycombinator.com/item?id=33083384 https://news.ycombinator.com/item?id=33083384
- gblargg 2y agoDoes the bank really read the amounts as hexadecimal?
- jks 2y agoHe used to send out real cheques for $2.56 but apparently they contained codes that could be used to transfer money out of his account in excess of the sum of the cheque. Now he uses the made-up Bank of San Serriffe, which naturally understands hexadecimal. https://www-cs-faculty.stanford.edu/~knuth/news08.html https://www-cs-faculty.stanford.edu/~knuth/news08.html
- jll29 2y agoI've emailed DEK to point out that the first person to break Enigma was not actually Alan M. Turing (as stated in one of the recent pre-fascicles) but the Polish mathematician Marian Rejewski (Turing's contribution was to automate the task, which was important because the rotors/settings were reconfigured by the German Wehrmacht every morning). Bletchley Park now has a prominent bust of Rejewski that credits his accomplishment. The Polish wisely passed on their knowledge to the British to keep the intel safe, because they expected a German invasion. On another note, I hope Professor Knuth has a continuity plan in place that ensures that his book series gets completed despite his advanced age (I'm worried about that, but tact prohibited me from asking, of course).
- WillAdams 2y agoGiven his quite healthy lifestyle, I believe that we should be okay on that latter front --- I certainly hope so.
- irrational 2y agoIt's not his lifestyle I'm worried about. There was a healthy youtuber who made videos about wilderness survival who was killed when he was rear ended by a drunk driver while stopped at a red light (the drunk driver, of course, survived). It's all the morons around Knuth I'm worried about.
- ks2048 2y agoI hate to be morbid and I wish him a long life, but at age 87, I don’t think drunk drivers are his biggest risk.
- rgmerk 2y agoThe book series will never be completed, and wouldn't be if Knuth lives to 120. And that's perfectly fine.
- mmooss 2y agoOT: Will Knuth's lifetime of work be used for learning input in AI systems, and does he control that? An AI application might make a good search interface for Knuth's opus.
- ForOldHack 2y agoTOACP The Art of Computer Programming, Volumes 1~4c https://en.wikipedia.org/wiki/The_Art_of_Computer_Programming https://en.wikipedia.org/wiki/The_Art_of_Computer_Programmin... Kudos to everyone who found bugs, and got the bounty. Congrats to everyone who used these to get their PhD-CS
- geophile 2y agoI first read parts of vol 1 in 1975, in my undergrad data structure and algorithm class. And then again in 1980 for my PhD comprehensive exams. That book is highly used. I found a pristine copy a few years in a pile of books on the sidewalk, thanks to someone moving. They put out a Unicomp clicky keyboard a few days later, picked up that too.
- svat 2y agoMy Knuth checks amount to a total account balance of 0x$b.40 at his "Bank of San Seriffe" (the equivalent of eleven "errors" and two "suggestions") — mostly accumulated over a short period several years ago. Previously, I had the impression that Knuth was some magical figure of perfection. What I realized was that the truth was more surprising: he makes the same kinds and the same frequency of errors as anyone else (in fact likely more, because every page is packed with a lot of detail); what sets him apart is that he cares so deeply about getting everything right — he has basically invited a DDoS on his time and attention, where every person in the world is strongly encouraged to write to him with errors on every page that he has ever written over several decades — and he does go back and look at all of them carefully (example: https://retrocomputing.stackexchange.com/questions/18117/which-computers-did-donald-knuth-mix-together-to-get-mix/18176#comment66965_18176 https://retrocomputing.stackexchange.com/questions/18117/whi...); and despite all this he somehow continues to function, producing new pages at a nonzero rate. After some experience with his responses (handwritten with pencil on a printout of the emails sent to him), I came away even more impressed.
- zoky 2y ago> he makes the same kinds and the same frequency of errors as anyone else Putting this here because I don’t know where else to tell this story and I simply have to share: I flew into Munich a few months ago, and since I have an EU passport I was able to use the shorter self-scan line for EU citizens at passport control. In front of me was an older couple who was having trouble with getting their passports to scan. I noticed they had US passports, so I politely informed the gentleman that he was in the wrong line. He turned around and thanked me, and that’s when I noticed the guy looked exactly like Donald Knuth! Before I could compose myself enough to say anything though, he and his wife had left to find the correct line. Obviously I couldn’t be sure it was him, but I checked Knuth’s public schedule and he was apparently speaking at some conference in Venice about two weeks later, so I’m guessing he decided to come a bit early and enjoy a vacation before the conference. So yeah, I’m like 99% sure I technically corrected an error by Donald Knuth, but unfortunately I missed out on my reward check. Didn’t even get a selfie with him.
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- ks2048 2y agoAnother top story on HN right now is how LLMs are finding errors in research papers. Maybe an LLM winning a Knuth bug bounty is a milestone on the path towards “AGI”?
- vacuity 2y agoAGI will be achieved when Knuth + LLMs work to finish TAOCP with no errors.
- deleted 2y ago[deleted]
- rgovostes 2y agoI haven't read TAOCP myself, but if I recall a lecture that Knuth gave, his algorithm analyses sometimes include cycle counts for his virtual MMIX architecture. He mentioned that these are counted by hand. If I were seeking a reward check, I would write a verifier to look for errors there.
- potus_kushner 2y agowould like to read, but the site uses some clownflare alternative, that just like clownflare tries to verify my browser (palemoon), and then comes to the conclusion that my browser isn't a browser.
- vzaliva 2y ago"he decided against breaking up Algorithm X between different pages" He should have used TeX ;) I've heard handles such layout problems automatically.