explain xkcd - User contributions [en]

Talk:2293: RIP John Conway

2020-04-14T10:35:06Z

162.158.92.54: Response to placeholder comic comment

This is really very impressive. The design of the stick figure to allow it to release a glider that ascends upwards (the "soul" rising to "heaven" or whatever) with the body decaying - that's a hard thing to get right using just the Game of Life rules. [[Special:Contributions/172.69.68.175|172.69.68.175]] 17:49, 13 April 2020 (UTC)
:Although Randall is clever, the Game of Life has been studied for so long that I'm sure this is a well-known animation. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 18:29, 13 April 2020 (UTC)
:: I played with the game a bunch in the past, but I've only done a bit of research after this appeared. I don't immediately find any previous report of this starting arrangement
:: This is unlikely, as the Game of Life has an uncountable number of patterns of this size, some of which are still being discovered. The pattern above is 7 cells wide by 9 cells tall - the number of distinct patterns that can be drawn in that box nears 2 --> 60 --> 1 (2^60). It's most likely that patterns such as this one are commonplace, and Randall just fiddled around until he reached one that he desired. The pattern itself, however, has likely never been discovered before. (As a fun postscript, [http://catagolue.appspot.com/object/xp16_0c2w3vz33032988/b3s23 a notable 8-cell wide, 9-cell tall pattern oscillating at period 16], just slightly larger than the one above, was discovered in February 2020.)[[User:Hdjensofjfnen|Hdjensofjfnen]] ([[User talk:Hdjensofjfnen|talk]]) 21:31, 13 April 2020 (UTC)
:::I suspect it's probably more likely that he worked it out backwards, rather than "just fiddled with it." [[Special:Contributions/108.162.216.244|108.162.216.244]] 04:24, 14 April 2020 (UTC)
::::AFAIK, many CAs such as Life have the property of being irreversible, which is the entire point for various pattern search efforts.[[Special:Contributions/162.158.92.54|162.158.92.54]] 07:13, 14 April 2020 (UTC)

was there a placeholder comic posted before the gif went live?

:I am certain there was one with "uh oh one of the lights went out" "that's not supposed to happen" and a picture of a pattern that I did not recognise, which I found to be quite sad. [[Special:Contributions/162.158.92.54|162.158.92.54]] 10:35, 14 April 2020 (UTC)

Looks like this is second animated comic in xkcd, besides 1116(though 1190 could be possibly counted together) [[Special:Contributions/172.69.190.16|172.69.190.16]] 19:34, 13 April 2020 (UTC)
:Uh, [[1331: Frequency]] and [[1264: Slideshow]] immediately come to mind, and then I remember about [[961: Eternal Flame]]. There's a lot more than two. [[User:Volleo6144|Volleo6144]] ([[User talk:Volleo6144|talk]]) 19:43, 13 April 2020 (UTC)
::[[:Category:Comics with animation]]; just added it. [[User:Yngvadottir|Yngvadottir]] ([[User talk:Yngvadottir|talk]]) 20:19, 13 April 2020 (UTC)

The explanation says that the simulation is run on an infinite grid, but even when the grid is calculated out beyond the border of the viewable area, bounding errors & boundary formations can occur. I've never seen ''any'' implementation that actually produces an infinite, nor even ''practically'' infinite grid. (In fact, wasn't there a Minecraft mod that runs until it lags out the engine?) Can anybody point me to a truly infinite grid implementation? Conway's ''definitely'' was not infinite, he even commented at length about the boundary formations that show up at the grid edges (which are among the most subjectively beautiful, incidentally). I think the explanation needs correction?
[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 21:59, 13 April 2020 (UTC)
: The explanation is describing Conway's game of life, not any particular implementation IMHO. No change needed IMHOA. Also, the previous post was not signed properly. [[Special:Contributions/162.158.107.167|162.158.107.167]] 21:47, 13 April 2020 (UTC)
::Except many of Conway's observations about the "game" & even ''his initial description'' of it explicitly state & indeed hinge upon the fact that it's not (& thus far ''cannot'' be) implemented as an "infinite" grid. Part of the whole point of his experiment with it & the various demonstrations is to illustrate edge effects resulting from a finite range of calculations. '''It's extremely relevant that it's''' '''''not''''' '''infinite.''' It's actually kinda the whole point of his creating it, much the same way people working with fractals likewise tend to become very interested in bounding errors. The boundaries are where the interesting work is done. Apparently someone agreed with me at least in part, because they edited the wording. Thanks... Brian? I think we should actually '''add''' to the description of the "game" info highlighting the edge effects, because that's the primary focus of the project & its outgrowths in the first place. (We can't adequately simulate infinity & that's a big part of the interest in it.) Also, I frequently have to submit & then refresh & sign afterward because of the device I'm on. In this case I'm glad I did, because I saw your reply & the other new stuff!
::[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 22:17, 13 April 2020 (UTC)
:Golly uses a grid of arbitrary size by default. It can very easily be verified to at least ±2<sup>10000</sup>. (Note that it also includes finite rectangular and toroidal grids.) [[User:LegionMammal978|LegionMammal978]] ([[User talk:LegionMammal978|talk]]) 01:39, 14 April 2020 (UTC)
No computer [Citation Needed] can run an ''actual'' infinite grid, but with some intelligent bounding you can mitigate early signs of problems by maintaining "bubbles" of cells with offsets. You get into problems once you start machine-gunning out gliders (offsets will eventually overflow or awkwardly lose precision, depending on the var-types used; and maintaining a longer and longer bubble, or more and more bubbles just above glider-sized, is probably your other challenge) but it's probably good enough for most purposes. If you somehow have finite patterns that move out in huge (wasteless) cycles from the 'origin' and hold that path until enacting hugely-delayed doglegs (mathematically, it must be a point no further away than can be reasonably enumerated by the bits of information contained within each formation, and significantly less as it'd be a far less efficient count-down cycler than any folded LFSR, but it's ''imaginable'') to meet again at some arbitrary (though deterministic and replicable) distance out in the far far reaches of your abstracted bubble-land then it's possible you could ''pretend'' you have infinite space. [[Special:Contributions/162.158.91.101|162.158.91.101]] 22:26, 13 April 2020 (UTC)

[[User:ProphetZarquon|ProphetZarquon]], do you have a source for your claim that the main point of Conway's creation of Life was to study the edge effects? [https://conwaylife.com/wiki/Conway%27s_Game_of_Life The page for Life on its own wiki] describes the Life grid as "infinite" and only mentions edge effects as inaccuracies to be avoided, and [https://www.youtube.com/watch?v=R9Plq-D1gEk this Conway interview about Life's creation] doesn't mention edges at all.
[[Special:Contributions/108.162.241.24|108.162.241.24]] 23:34, 13 April 2020‎ (UTC)
:First of all, as a tip, reply directly to the comment when you want to talk with someone. Secondly, yeah, I'm pretty sure that person's just blasting ass ham. [[Special:Contributions/172.69.69.28|172.69.69.28]] 02:49, 14 April 2020 (UTC)

Possibly worth noting is the bit of artistry in the rendering. Munroe alters the step period of the iterations so that the deconstruction of the humanoid shape happens more quickly, with the stepping of the glider translating away occurring more slowly. [[User:Fixer|Fixer]] ([[User talk:Fixer|talk]]) 21:52, 13 April 2020 (UTC)

I like the comic very much, and I'm afraid to say I hadn't heard of his death in amongst... well, everything else. RIP.
While I'm here, though, I'm a bit concerned about the current cell generation cycle explanation, as it feels awkward. Currently it is (paraphrased) "live cells survive if just enough neighbours / dead cells come to life with exactly enough neighbours / any other dies or stays dead". I'd prefer something that more delineates it as birth (dead to live, by propogation from the right number of live neighbours), death (live to dead due to ''either'' isolation ''or'' overcrowding) and continuation of state in all other cases. Can't work out a good phrasing yet, but ''may'' try it out later. [[Special:Contributions/162.158.91.101|162.158.91.101]] 22:26, 13 April 2020 (UTC)
: Agreed 100%. I believe the problem lies in the confusion between "cell as in biology" versus "cell as in jail". It would be better to avoid the word "cell" and describe a grid with squares that are either inhabited or empty; inhabitants with two or three neighbours survive to the next generation, otherwise they die (square becomes empty the next generation); exactly three neighbours to an empty square will give birth (become inhabited) in the next generation; and any other empty square stays empty.

Given the cause of death, should this comic be listed among the Covid-19 series? [[User:Momerath|Momerath]] ([[User talk:Momerath|talk]]) 05:02, 14 April 2020 (UTC)

Talk:2293: RIP John Conway

2020-04-14T07:13:11Z

162.158.92.54: "backwards?!"

This is really very impressive. The design of the stick figure to allow it to release a glider that ascends upwards (the "soul" rising to "heaven" or whatever) with the body decaying - that's a hard thing to get right using just the Game of Life rules. [[Special:Contributions/172.69.68.175|172.69.68.175]] 17:49, 13 April 2020 (UTC)
:Although Randall is clever, the Game of Life has been studied for so long that I'm sure this is a well-known animation. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 18:29, 13 April 2020 (UTC)
:: I played with the game a bunch in the past, but I've only done a bit of research after this appeared. I don't immediately find any previous report of this starting arrangement
:: This is unlikely, as the Game of Life has an uncountable number of patterns of this size, some of which are still being discovered. The pattern above is 7 cells wide by 9 cells tall - the number of distinct patterns that can be drawn in that box nears 2 --> 60 --> 1 (2^60). It's most likely that patterns such as this one are commonplace, and Randall just fiddled around until he reached one that he desired. The pattern itself, however, has likely never been discovered before. (As a fun postscript, [http://catagolue.appspot.com/object/xp16_0c2w3vz33032988/b3s23 a notable 8-cell wide, 9-cell tall pattern oscillating at period 16], just slightly larger than the one above, was discovered in February 2020.)[[User:Hdjensofjfnen|Hdjensofjfnen]] ([[User talk:Hdjensofjfnen|talk]]) 21:31, 13 April 2020 (UTC)
:::I suspect it's probably more likely that he worked it out backwards, rather than "just fiddled with it." [[Special:Contributions/108.162.216.244|108.162.216.244]] 04:24, 14 April 2020 (UTC)
::::AFAIK, many CAs such as Life have the property of being irreversible, which is the entire point for various pattern search efforts.[[Special:Contributions/162.158.92.54|162.158.92.54]] 07:13, 14 April 2020 (UTC)

was there a placeholder comic posted before the gif went live?

Looks like this is second animated comic in xkcd, besides 1116(though 1190 could be possibly counted together) [[Special:Contributions/172.69.190.16|172.69.190.16]] 19:34, 13 April 2020 (UTC)
:Uh, [[1331: Frequency]] and [[1264: Slideshow]] immediately come to mind, and then I remember about [[961: Eternal Flame]]. There's a lot more than two. [[User:Volleo6144|Volleo6144]] ([[User talk:Volleo6144|talk]]) 19:43, 13 April 2020 (UTC)
::[[:Category:Comics with animation]]; just added it. [[User:Yngvadottir|Yngvadottir]] ([[User talk:Yngvadottir|talk]]) 20:19, 13 April 2020 (UTC)

The explanation says that the simulation is run on an infinite grid, but even when the grid is calculated out beyond the border of the viewable area, bounding errors & boundary formations can occur. I've never seen ''any'' implementation that actually produces an infinite, nor even ''practically'' infinite grid. (In fact, wasn't there a Minecraft mod that runs until it lags out the engine?) Can anybody point me to a truly infinite grid implementation? Conway's ''definitely'' was not infinite, he even commented at length about the boundary formations that show up at the grid edges (which are among the most subjectively beautiful, incidentally). I think the explanation needs correction?
[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 21:59, 13 April 2020 (UTC)
: The explanation is describing Conway's game of life, not any particular implementation IMHO. No change needed IMHOA. Also, the previous post was not signed properly. [[Special:Contributions/162.158.107.167|162.158.107.167]] 21:47, 13 April 2020 (UTC)
::Except many of Conway's observations about the "game" & even ''his initial description'' of it explicitly state & indeed hinge upon the fact that it's not (& thus far ''cannot'' be) implemented as an "infinite" grid. Part of the whole point of his experiment with it & the various demonstrations is to illustrate edge effects resulting from a finite range of calculations. '''It's extremely relevant that it's''' '''''not''''' '''infinite.''' It's actually kinda the whole point of his creating it, much the same way people working with fractals likewise tend to become very interested in bounding errors. The boundaries are where the interesting work is done. Apparently someone agreed with me at least in part, because they edited the wording. Thanks... Brian? I think we should actually '''add''' to the description of the "game" info highlighting the edge effects, because that's the primary focus of the project & its outgrowths in the first place. (We can't adequately simulate infinity & that's a big part of the interest in it.) Also, I frequently have to submit & then refresh & sign afterward because of the device I'm on. In this case I'm glad I did, because I saw your reply & the other new stuff!
::[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 22:17, 13 April 2020 (UTC)
:Golly uses a grid of arbitrary size by default. It can very easily be verified to at least ±2<sup>10000</sup>. (Note that it also includes finite rectangular and toroidal grids.) [[User:LegionMammal978|LegionMammal978]] ([[User talk:LegionMammal978|talk]]) 01:39, 14 April 2020 (UTC)
No computer [Citation Needed] can run an ''actual'' infinite grid, but with some intelligent bounding you can mitigate early signs of problems by maintaining "bubbles" of cells with offsets. You get into problems once you start machine-gunning out gliders (offsets will eventually overflow or awkwardly lose precision, depending on the var-types used; and maintaining a longer and longer bubble, or more and more bubbles just above glider-sized, is probably your other challenge) but it's probably good enough for most purposes. If you somehow have finite patterns that move out in huge (wasteless) cycles from the 'origin' and hold that path until enacting hugely-delayed doglegs (mathematically, it must be a point no further away than can be reasonably enumerated by the bits of information contained within each formation, and significantly less as it'd be a far less efficient count-down cycler than any folded LFSR, but it's ''imaginable'') to meet again at some arbitrary (though deterministic and replicable) distance out in the far far reaches of your abstracted bubble-land then it's possible you could ''pretend'' you have infinite space. [[Special:Contributions/162.158.91.101|162.158.91.101]] 22:26, 13 April 2020 (UTC)

[[User:ProphetZarquon|ProphetZarquon]], do you have a source for your claim that the main point of Conway's creation of Life was to study the edge effects? [https://conwaylife.com/wiki/Conway%27s_Game_of_Life The page for Life on its own wiki] describes the Life grid as "infinite" and only mentions edge effects as inaccuracies to be avoided, and [https://www.youtube.com/watch?v=R9Plq-D1gEk this Conway interview about Life's creation] doesn't mention edges at all.
[[Special:Contributions/108.162.241.24|108.162.241.24]] 23:34, 13 April 2020‎ (UTC)
:First of all, as a tip, reply directly to the comment when you want to talk with someone. Secondly, yeah, I'm pretty sure that person's just blasting ass ham. [[Special:Contributions/172.69.69.28|172.69.69.28]] 02:49, 14 April 2020 (UTC)

Possibly worth noting is the bit of artistry in the rendering. Munroe alters the step period of the iterations so that the deconstruction of the humanoid shape happens more quickly, with the stepping of the glider translating away occurring more slowly. [[User:Fixer|Fixer]] ([[User talk:Fixer|talk]]) 21:52, 13 April 2020 (UTC)

I like the comic very much, and I'm afraid to say I hadn't heard of his death in amongst... well, everything else. RIP.
While I'm here, though, I'm a bit concerned about the current cell generation cycle explanation, as it feels awkward. Currently it is (paraphrased) "live cells survive if just enough neighbours / dead cells come to life with exactly enough neighbours / any other dies or stays dead". I'd prefer something that more delineates it as birth (dead to live, by propogation from the right number of live neighbours), death (live to dead due to ''either'' isolation ''or'' overcrowding) and continuation of state in all other cases. Can't work out a good phrasing yet, but ''may'' try it out later. [[Special:Contributions/162.158.91.101|162.158.91.101]] 22:26, 13 April 2020 (UTC)
: Agreed 100%. I believe the problem lies in the confusion between "cell as in biology" versus "cell as in jail". It would be better to avoid the word "cell" and describe a grid with squares that are either inhabited or empty; inhabitants with two or three neighbours survive to the next generation, otherwise they die (square becomes empty the next generation); exactly three neighbours to an empty square will give birth (become inhabited) in the next generation; and any other empty square stays empty.

Given the cause of death, should this comic be listed among the Covid-19 series? [[User:Momerath|Momerath]] ([[User talk:Momerath|talk]]) 05:02, 14 April 2020 (UTC)

Talk:2200: Unreachable State

2019-09-11T08:03:46Z

162.158.92.54: Note about undefined behavior and assertion failures.

When I tried to go here originally, it was unreachable. [[Special:Contributions/162.158.107.61|162.158.107.61]] 03:54, 11 September 2019 (UTC)

nothing about the comic suggests a website. it looks more like the error message of a program. also, i don't think CB is typing it, just reading. [[Special:Contributions/172.68.50.124|172.68.50.124]] 06:20, 11 September 2019 (UTC)

== "Can't happen" ==

This comic is not about "a problem that the programmers did not anticipate", but rather a situation that the programmer rules out as impossible, which is technically called "Can't happen" or "Impossible Error" in the hacker/programmer's jargon. See http://catb.org/jargon/html/C/can-t-happen.html

For example:
<source lang=php>
for ($i=1;$i<=5;++$i) {echo $i." - ";}
if ($i<10) {echo "Bye!";} else {echo "Can't happen!";}
</source>

[[User:ElfQrin|ElfQrin]] ([[User talk:ElfQrin|talk]]) 07:14, 11 September 2019 (UTC)

Also it helps not to be too cute even with impossible error messages. A colleague left a message along the lines of <q>Application rubbish bin has broken.</q> once. Cue a somewhat perplexed user call several years later…
<blockquote>
“Scientists have calculated that the chances of something so patently absurd actually existing are millions to one.
But magicians have calculated that million-to-one chances crop up nine times out of ten.”

― Terry Pratchett, Mort
</blockquote>

--[[User:Kventin|Kventin]] ([[User talk:Kventin|talk]]) 07:51, 11 September 2019 (UTC)

The "anything can happen" may be reference to undefined behavior in some programming languages (most famous are C and C++) https://en.wikipedia.org/wiki/Undefined_behavior. And the error message is rather about assertion failure https://en.wikipedia.org/wiki/Assertion_(software_development) [[Special:Contributions/162.158.92.54|162.158.92.54]] 08:03, 11 September 2019 (UTC)

Talk:2194: How to Send a File

2019-08-27T13:32:31Z

162.158.92.54:

Anyone else find it annoying to have the regular comic co-opted for advertising a book? [[User:Ianrbibtitlht|Ianrbibtitlht]] ([[User talk:Ianrbibtitlht|talk]]) 20:30, 26 August 2019 (UTC)
:There probably are, but I'll excuse Randal because he provides* such entertaining comic for free.
:''*usually and arguably'' [[User:RIIW - Ponder it|RIIW - Ponder it]] ([[User talk:RIIW - Ponder it|talk]]) 21:00, 26 August 2019 (UTC)
:I don't mind. If it was a frequent occurrence perhaps, but this is, what, twice in over a dozen years? And he includes humor in the ads, so it's not like we completely miss out. [[User:N0lqu|-boB]] ([[User talk:N0lqu|talk]]) 21:08, 26 August 2019 (UTC)

Pedantry section: If you have a dockable tablet computer - I do - then the files are in the screen part, and the keyboard and trackpad probably can't contain files. Also, you don't need scissors to separate them, there's usually a button to press or magnets or something. And technically you probably could mail the tablet... but I usually wouldn't. rja.carnegie@gmail.com [[Special:Contributions/162.158.154.31|162.158.154.31]] 21:54, 26 August 2019 (UTC)
:If you start being pedantric... Google the meaning of the word "usually". Let's talk again afterwards. Also you do not need to (but I guess you are allowed to) put your email as a signature. If you want to be reachable/track your comments/etc. You can just easily register to this wiki, and then have your profile added instead of that random IP. I personally never recieved spam, etc. from this site. --[[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 07:18, 27 August 2019 (UTC)

I annually have to send several terabytes of data to a co-worker who needs to analyze and then retain it for some months. We snail mail SS hard drives around since we own them, and the data is originally accumulated on them. Short of switching to SD cards I am not sure there is a better way even in 2019.... [[Special:Contributions/108.162.241.22|108.162.241.22]] 02:20, 27 August 2019 (UTC)

It is important to know which part of the computer your files are in. Mine are usually in the little rectangular prism stuck in the side. No need to cut up the computer, as I can just pull out the rectangular prism after telling the operating system I am going to do that. [[User:Nutster|Nutster]] ([[User talk:Nutster|talk]]) 04:49, 27 August 2019 (UTC)

Missed the obvious chance to make a pun: butterfiles. [[Special:Contributions/162.158.92.54|162.158.92.54]] 13:32, 27 August 2019 (UTC)