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A decades-old bug in Knuth's long division (TAOCP Vol II, Algorithm 4.3.1D)

kolja.rs

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Re: A decades-old bug in Knuth's long division (TAOCP Vol II, Algorithm 4.3.1D)

#11

Post by nk_kolja »

malisper wrote: post #8
WillAdams wrote: post #5

Earlier quoted context omitted.

Unfortunately, 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 (unfortunately, I have yet to find another typo since getting my $2.88 for _Digital Typography_)

You still get a physical piece of paper that looks like a check; it's just not a valid check.

It can still be cashed in, though not in any bank, you need to contact Knuth beforehand.

For me it will stay framed on the wall.

Re: A decades-old bug in Knuth's long division (TAOCP Vol II, Algorithm 4.3.1D)

#12

Post by nk_kolja »

ginko wrote: post #6

The typesetting of this looks very broken on firefox with extreme gaps between lines of text. Seems to render fine on chromium.

Thank you for letting me now, but I cannot replicate the issue on Firefox. There are some issues with math and the animations not breaking on mobile, which I am working on repairing. (fixed)

EDIT: I have added a different fallback font so it should work on your Firefox now.

Re: A decades-old bug in Knuth's long division (TAOCP Vol II, Algorithm 4.3.1D)

#14

Post by globular-toast »

> "I'm especially glad to have this correction, because I think the readers of TAOCP Vol 2 look at Algorithm 4.3.1 D more than any other algorithm!"

If you look at the fore edge of my copy of vol 2 will see a noticeably grubby line. Open the book at that page and you do indeed arrive at Algorithm D!

I've implemented multiple-precision arithmetic at least a couple of times. I'm tempted to dig up an old project I haven't touched for over a decade and make the correction...

Re: A decades-old bug in Knuth's long division (TAOCP Vol II, Algorithm 4.3.1D)

#15

Post by WillAdams »

nk_kolja wrote: post #11
malisper wrote: post #8

Earlier quoted context omitted.

You still get a physical piece of paper that looks like a check; it's just not a valid check.

It can still be cashed in, though not in any bank, you need to contact Knuth beforehand. For me it will stay framed on the wall.

I wonder if one can do the reverse? Turn in a physical check and get an account?

Re: A decades-old bug in Knuth's long division (TAOCP Vol II, Algorithm 4.3.1D)

#16

Post by voakbasda »

ginko wrote: post #6

The typesetting of this looks very broken on firefox with extreme gaps between lines of text. Seems to render fine on chromium.

I believe this is a missing font issue, whereupon Firefox chooses very poor substitutes. I ran into this recently on one of my machines and solved it by installing the Microsoft fonts package (or possibly another one… I can’t remember now exactly which one did the trick).

Re: A decades-old bug in Knuth's long division (TAOCP Vol II, Algorithm 4.3.1D)

#17

Post by AndruLuvisi »

nk_kolja wrote: post #2

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 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 fo…

Wow, congratulations on finding this most epic bug!

Re: A decades-old bug in Knuth's long division (TAOCP Vol II, Algorithm 4.3.1D)

#18

Post by ginko »

voakbasda wrote: post #16
ginko wrote: post #6

The typesetting of this looks very broken on firefox with extreme gaps between lines of text. Seems to render fine on chromium.

I believe this is a missing font issue, whereupon Firefox chooses very poor substitutes. I ran into this recently on one of my machines and solved it by installing the Microsoft fonts package (or possibly another one… I can’t remember now exactly which one did the trick).

Right, missing fonts could be the issue on my end.

Re: A decades-old bug in Knuth's long division (TAOCP Vol II, Algorithm 4.3.1D)

#19

Post by bluGill »

WillAdams wrote: post #5
jason_s wrote: post #3

Earlier quoted context omitted.

Congratulations! Wow, you got a legendary $2.56 check....

Unfortunately, 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 (unfortunately, I have yet to find another typo since getting my $2.88 for _Digital Typography_)

Close enough. If I ever got such a check it would be professionally framed and hung on my wall. As would most people reading this.
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