Search found 3622 matches

by PM 2Ring
Sun May 06, 2018 8:10 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1989: "IMHO"
Replies: 110
Views: 3987

Re: 1989: "IMHO"

Ah yes, Jaffics Interchange Format. Giraffe-ics Interchange Format? Giraffics Interchange Format https://i.imgur.com/nCTjG87.gif Exactly. I've also heard of people pronounce JPEG as, "jay-peg," like Joint Potographic Experts Group. I thought it was Joyful Pornographic Entertainment Graphi...
by PM 2Ring
Sat Mar 31, 2018 7:40 pm UTC
Forum: General
Topic: Lucky Ten Thousand (TIL)
Replies: 13380
Views: 1394738

Re: Lucky Ten Thousand (TIL)

FWIW I'm looking for something like how a person with good attention is attentive, a person with good focus is focused, a person with good dedication is dedicated, a person with good memory is... memor... able? no... iful? that's not a word... what? How about memorious? https://en.wikipedia.org/wik...
by PM 2Ring
Sat Mar 17, 2018 4:38 am UTC
Forum: Science
Topic: Quantum Question
Replies: 110
Views: 8237

Re: Quantum Question

I read an article that suggested that quantum entanglement could be explained without spooky action if causality breaks down at the quantum level - i.e. a particle sends a message back in time to its twin about how it should spin, etc. If true, IYHO would this qualify as a major revision of QM or j...
by PM 2Ring
Tue Jan 02, 2018 10:41 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1935: "2018"
Replies: 66
Views: 5850

Re: 1935: "2018"

The mean tropical year is measured at 365.24219 days, but is gradually getting smaller because the slowing of the earth's rotation is making the days longer. This means that in the long-run my system would be more accurate than either of those proposals. In discussions like this one the mean Gregor...
by PM 2Ring
Thu Nov 30, 2017 8:49 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1918: "NEXUS"
Replies: 25
Views: 3722

Re: 1918: "NEXUS"

aaronb1138 wrote:Need to find some way of getting the alt-text in the printout.

The mobile view at m.xkcd.com can display the alt text.
by PM 2Ring
Thu Oct 26, 2017 8:29 pm UTC
Forum: Mathematics
Topic: What is a Euclidean Number
Replies: 13
Views: 2625

Re: What is a Euclidean Number

They forgot to mention that the number of repetitions is supposed to be finite. Of course there are infinite sequences whose limit is a constructible number, but in general that's not the case. If you permit infinite sequences then any real number can be constructed. I was going to say something abo...
by PM 2Ring
Wed Sep 27, 2017 12:39 pm UTC
Forum: Mathematics
Topic: Possible "Spot it!"-like decks
Replies: 30
Views: 5416

Re: Possible "Spot it!"-like decks

I've been following this thread since it started but I apologize that I'm a bit late in posting to it; I got caught up learning about finite projective geometry . ;) As Soupspoon noted, it's easy enough to solve the cases with R=2. And as mentioned on Stack Exchange, we can use finite fields to qui...
by PM 2Ring
Fri Aug 25, 2017 5:12 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 0936: "Password Strength"
Replies: 893
Views: 275867

Re: 0936: "Password Strength"

@morris But why do you want to eliminate doubled letters? All else being equal, the total number of passwords when doubles are allowed is larger than the total number of passwords with doubles banned. So eliminating doubles makes password generation more complex and makes it easier to crack the pass...
by PM 2Ring
Fri Aug 25, 2017 5:00 pm UTC
Forum: Science
Topic: American solar eclipse
Replies: 44
Views: 4883

Re: American solar eclipse

Shadows under trees look strange during an eclipse. All the little gaps in the foliage act like pinhole cameras, and normally they project circular images of the Sun, creating the familiar dappling. But during an eclipse that dappling pattern is modified because the Sun images become crescents. You ...
by PM 2Ring
Thu Jun 01, 2017 1:17 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1843: "Opening Crawl"
Replies: 19
Views: 4115

Re: 1843: "Opening Crawl"

Seriously, though, I probably gave you one of the big two reasons for me to still use it, i.e. "telnet http://www.dodgyserver.cz 80", or 8080 or 8000 or..., then something like "GET /shared/docs/banknamelogin.html HTTP/1.1 <enter><enter>" (then again with a HOST: line, etc), to ...
by PM 2Ring
Wed May 31, 2017 10:35 am UTC
Forum: Mathematics
Topic: Interesting question regarding Fermat nested radicals
Replies: 9
Views: 2735

Re: Interesting question regarding Fermat nested radicals

I've done some more work on estimating the tail term of the transformed nested radical. To estimate the tail of the i'th term we can use https://i.stack.imgur.com/xbAw6.png Here are the a j 0: phi, 1: -2 + 2 * phi, 2: 14 - 8 * phi, 3: -72 + 44 * phi, 4: 410 - 250 * phi, 5: -4340 + 2680 * phi, 6: 447...
by PM 2Ring
Fri May 26, 2017 1:02 pm UTC
Forum: General
Topic: [SAFESPACE] LGBTIQQA Thread - Queer Support!
Replies: 8197
Views: 1204822

Re: [SAFESPACE] LGBTIQQA Thread - Queer Support!

Right on. So my read of the situation is that gender queer people are neutral in terms of gender. Neither male nor female. Or do you (general "you") choose a gender you like more that day and go with that? Sounds like the possibly related term gender fluid. I might be in the T spectrum of...
by PM 2Ring
Fri May 26, 2017 11:35 am UTC
Forum: Mathematics
Topic: Interesting question regarding Fermat nested radicals
Replies: 9
Views: 2735

Re: Interesting question regarding Fermat nested radicals

here's the corresponding OEIS page and it provides a an alternate equivalent formula which looks much easier to work with and also a efficient algorithm https://oeis.org/A273580 and a lookup in https://isc.carma.newcastle.edu.au/advancedCalc gives no results ;( Nice! I like that transformation. In ...
by PM 2Ring
Wed May 24, 2017 1:33 pm UTC
Forum: Mathematics
Topic: Interesting question regarding Fermat nested radicals
Replies: 9
Views: 2735

Re: Interesting question regarding Fermat nested radicals

My guess is that it converges, or if it diverges it does so extremely slowly. ;)

A brute-force calculation (using mpmath) of 500 terms with 1000 decimal digits of precision yields

3.398589439226157032953566735957045
by PM 2Ring
Mon May 22, 2017 9:58 am UTC
Forum: Coding
Topic: var == 'value' vs 'value' == var
Replies: 20
Views: 6982

Re: var == 'value' vs 'value' == var

by PM 2Ring
Sat May 20, 2017 8:38 am UTC
Forum: Science
Topic: Bad science jokes!
Replies: 100
Views: 32099

Re: Bad science jokes!

Here's one for the chemists, and physicists interested in atomic orbitals.

Q: Where do you find 2d electrons?
Spoiler:
A: In flat batteries.
by PM 2Ring
Sat May 20, 2017 8:30 am UTC
Forum: Coding
Topic: Basic Question Involving Functions (Python)
Replies: 18
Views: 6100

Re: Basic Question Involving Functions (Python)

I'm trying to learn a programming language, and after some research decided to explore Python. Given the conceptual difficulties that you've had in your Mathematics threads http://forums.xkcd.com/viewtopic.php?f=17&t=122713 and http://forums.xkcd.com/viewtopic.php?f=17&t=122712 I really don...
by PM 2Ring
Mon May 08, 2017 4:51 pm UTC
Forum: Coding
Topic: Basic Question Involving Functions (Python)
Replies: 18
Views: 6100

Re: Basic Question Involving Functions (Python)

I'm trying to learn a programming language, and after some research decided to explore Python. Given the conceptual difficulties that you've had in your Mathematics threads http://forums.xkcd.com/viewtopic.php?f=17&t=122713 and http://forums.xkcd.com/viewtopic.php?f=17&t=122712 I really don...
by PM 2Ring
Sun May 07, 2017 10:05 am UTC
Forum: Mathematics
Topic: Halting Problem
Replies: 208
Views: 22931

Re: Halting Problem

Can someone help me figure out what happens next? Does Oracle itself get stuck in an infinite loop, or does Devious actually get to the do-the-opposite stage with respect to Oracle? Oracle does NOT run Devious, it analyzes it to see how it would behave if passed the given data, which just happens t...
by PM 2Ring
Fri Apr 14, 2017 4:52 pm UTC
Forum: Site/Forum issues
Topic: Incorrect encoding on JSONP API
Replies: 5
Views: 6345

Re: Incorrect encoding on JSONP API

It's still there. In https://xkcd.com/1824/info.0.json we have

Code: Select all

alt": "Be careful—it's breeding season, and some of these can be *extremely* defensive of their nests.",


BTW, this bug was mentioned on Stack Overflow Meta.
by PM 2Ring
Tue Apr 11, 2017 9:22 am UTC
Forum: Coding
Topic: Getting the most recent comic
Replies: 24
Views: 84403

Re: Getting the most recent comic

FWIW, I just posted a Python 2/3 script in the General thread Date for a comic? which fetches the JSON of a comic and prints its title and publication date.
by PM 2Ring
Tue Apr 11, 2017 9:14 am UTC
Forum: General
Topic: Date for a comic?
Replies: 3
Views: 2859

Re: Date for a comic?

You can get the date of a comic from the JSON feed. For that comic, the JSON is at http://xkcd.com/1425/info.0.json . Your browser may have an extension that formats JSON data nicely. Or if you have Python and you aren't afraid to use the command line, you can use the following script to fetch the J...
by PM 2Ring
Mon Apr 03, 2017 4:13 pm UTC
Forum: General
Topic: Lucky Ten Thousand (TIL)
Replies: 13380
Views: 1394738

Re: Lucky Ten Thousand (TIL)

WibblyWobbly wrote:Sorry, don't mean to harp on typos, but this one might cause confusion - it's "Verlet", isn't it?

Oops! Thanks for that!
by PM 2Ring
Mon Apr 03, 2017 12:47 pm UTC
Forum: General
Topic: Lucky Ten Thousand (TIL)
Replies: 13380
Views: 1394738

Re: Lucky Ten Thousand (TIL)

[edit]good news everyone, with RK4 implemented it is wonderfully stable. Even if I drop the plane from 1km, it just sinks through the ground (the spring really is more like a rubber sheet at 1m height and the ground is just a hologram) and comes back up.[/edit] Yay! You might also like to take a lo...
by PM 2Ring
Thu Mar 30, 2017 5:40 pm UTC
Forum: Science
Topic: The Reverse of how colors work: how would it look?
Replies: 6
Views: 2796

Re: The Reverse of how colors work: how would it look?

Here are a pair of images that approximately illustrate what you're asking about. The colours of one image are the RGB complement of the other image, so the hues of corresponding pixels are 180 degrees out of phase, but they have the same saturation and value (brightness). Well, sort of :) for the r...
by PM 2Ring
Wed Mar 22, 2017 5:16 am UTC
Forum: General
Topic: Whetstones and Sharp Knives
Replies: 12
Views: 3612

Re: Whetstones and Sharp Knives

You may find this recent Cooking Stack Exchange question of interest: Do magnets dull knives?
by PM 2Ring
Sun Mar 19, 2017 3:52 pm UTC
Forum: Coding
Topic: Coding: Fleeting Thoughts
Replies: 9848
Views: 1707364

Re: Coding: Fleeting Thoughts

Actual coding question: I'm working with a class that wraps two dictionaries -- one that maps a unique value ("A") to a non-unique value ("b"), and one that maps that non-unique to a set containing all the unique values that are mapped to it. In other words, as one dictionary ma...
by PM 2Ring
Mon Mar 13, 2017 2:03 am UTC
Forum: Language/Linguistics
Topic: Miscellaneous language questions
Replies: 549
Views: 68687

Re: Miscellaneous language questions

ObLink: My Old Man's A Dustman - Lonnie Donegan.

Another old term from the days of coal ash is "ashcan".
by PM 2Ring
Fri Mar 10, 2017 7:19 am UTC
Forum: Computer Science
Topic: A Compact Sized "Why?-BOOM" machine.
Replies: 7
Views: 4015

Re: A Compact Sized "Why?-BOOM" machine.

I've read a few stories where computers were wrecked / frozen by setting them impossible or difficult tasks, eg, some version of the Liar Paradox , find the last digit of pi, prove Goldbach's conjecture, etc. One memorable short story in this genre is The Monkey Wrench by Gordon R Dickson. Spock use...
by PM 2Ring
Fri Mar 10, 2017 6:50 am UTC
Forum: Science
Topic: Free Will
Replies: 161
Views: 18466

Re: Free Will

Here are some other threads on Free Will and Determinism from the Science forum.

Is there randomness to the universe?
Wait, can free will exist?
Does it matter whether God plays dice?

There are also various threads in Serious Business.
by PM 2Ring
Thu Feb 16, 2017 8:28 am UTC
Forum: Mathematics
Topic: "There is an Exception to every rule"
Replies: 32
Views: 7242

Re: "There is an Exception to every rule"

This got me thinking - 18 is a really boring, uncool number. Like, unusually so, so much that nothing could be more boring or uncool. I'd definitely choose 18 as an ususual example of a number of unparalleled uncoolness. In other words, 18 is a prime odd perfect square. Here's a reasonably cool pro...
by PM 2Ring
Fri Dec 30, 2016 7:58 am UTC
Forum: Mathematics
Topic: Combinatoric commanders
Replies: 6
Views: 2252

Re: Combinatoric commanders

I'll represent the colors by their initials, except I'll use the printers' convention of using K for black, so our colors in color-wheel order are WBKRG. The official convention is to use B for black and U for blue. Ah, ok. I'm not really into Pokémon I don't know much about M:tG. If you want t...
by PM 2Ring
Thu Dec 29, 2016 12:23 pm UTC
Forum: Mathematics
Topic: Combinatoric commanders
Replies: 6
Views: 2252

Re: Combinatoric commanders

I'll represent the colors by their initials, except I'll use the printers' convention of using K for black, so our colors in color-wheel order are WBKRG. The 5 four-color cards are BKRG WKRG WBRG WBKG WBKR The 15 two-color cards are WB BK KR RG GW WK KW WR RW BR RB BG GB KG GK For each color there a...
by PM 2Ring
Thu Dec 29, 2016 9:59 am UTC
Forum: Coding
Topic: Coding: Fleeting Thoughts
Replies: 9848
Views: 1707364

Re: Coding: Fleeting Thoughts

[...] why would IEEE create a function whose ostensive purpose is to calculate which integer is less than or equal to.... and not actually return an integer? Because a machine integer is not big enough to hold all possible results of floor . Of course, double can't represent very large integers exa...
by PM 2Ring
Wed Dec 28, 2016 7:40 am UTC
Forum: Coding
Topic: Coding: Fleeting Thoughts
Replies: 9848
Views: 1707364

Re: Coding: Fleeting Thoughts

Don't think of // as integer division: it's floor division. Shouldn't floor return an integer, though (like it does in Haskell)? (At least, if you have bigints and don't have to worry about floor(1.0e308) not being representable as an int; but I'm pretty sure Python does have bigints.) I'd expect 3...
by PM 2Ring
Wed Dec 28, 2016 7:29 am UTC
Forum: Computer Science
Topic: Deliberately bad algorithms
Replies: 120
Views: 40973

Re: Deliberately bad algorithms

A classical bad algorithm for Fibonacci's numbers: ulong Fibonacci(uint x) { if(x==0) return 0; else if(x==1) return 1; else return Fibonacci(x-1)+Fibonacci(x-2); } Okay, it computes the value exactly by definition, but... That algorithm got a mention back on page 1. Also see Xanthir's sig. Actuall...
by PM 2Ring
Wed Dec 28, 2016 6:40 am UTC
Forum: Coding
Topic: Coding: Fleeting Thoughts
Replies: 9848
Views: 1707364

Re: Coding: Fleeting Thoughts

>>> 3 // 2 1 >>> 3.0 // 2 1.0 Python, do you really have to be like that? It's so close, but worse than not close. Trying to maintain compatibility between Python 2.7 and 3 is a pain the arse when you don't have a proper environment for the latter set up. Don't think of // as integer division: it's...
by PM 2Ring
Fri Nov 25, 2016 8:06 am UTC
Forum: Coding
Topic: Efficiency of prime sieve
Replies: 7
Views: 5304

Re: Efficiency of prime sieve

If you're interested in storing primes, note that all primes > 30 are of the form 30n + {1,7,11,13,17,19,23,29}. There are 8 numbers in that set, so you can use a single byte to indicate all the primes in a block of 30 numbers. It's not too hard to write sieve algorithms so that they store the sieve...
by PM 2Ring
Fri Nov 25, 2016 6:12 am UTC
Forum: Science
Topic: Miscellaneous Science Questions
Replies: 2863
Views: 614709

Re: RELATIVITY QUESTIONS! (and other common queries)

As usual QM seems to be crashing the party . But at least it fixes those awful singularities and other problems. That Scharnhorst effect is interesting, but it only appears problematic if you define c to be the speed of light in a normal vacuum. If you use the more fundamental definition that it's ...
by PM 2Ring
Tue Oct 25, 2016 3:54 am UTC
Forum: Mathematics
Topic: Primes under different moduli
Replies: 4
Views: 2234

Re: Primes under different moduli

Using mod 30 is nice because you can use one byte to hold the 8 potential primes in each block of 30 numbers (apart from the first block). I wrote a segmented sieve in C using this technique many years ago, when RAM and HD space was much smaller than it is today.

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