## Search found 3691 matches

Fri May 26, 2017 1:02 pm UTC
Forum: General
Topic: [SAFESPACE] LGBTIQQA Thread - Queer Support!
Replies: 8248
Views: 1447847

### 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...
Fri May 26, 2017 11:35 am UTC
Forum: Mathematics
Topic: Interesting question regarding Fermat nested radicals
Replies: 9
Views: 3991

### 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 ...
Wed May 24, 2017 1:33 pm UTC
Forum: Mathematics
Topic: Interesting question regarding Fermat nested radicals
Replies: 9
Views: 3991

### 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
Mon May 22, 2017 9:58 am UTC
Forum: Coding
Topic: var == 'value' vs 'value' == var
Replies: 20
Views: 13727

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

Sat May 20, 2017 8:38 am UTC
Forum: Science
Replies: 100
Views: 35639

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

Q: Where do you find 2d electrons?
Spoiler:
A: In flat batteries.
Sat May 20, 2017 8:30 am UTC
Forum: Coding
Topic: Basic Question Involving Functions (Python)
Replies: 18
Views: 11470

### 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...
Mon May 08, 2017 4:51 pm UTC
Forum: Coding
Topic: Basic Question Involving Functions (Python)
Replies: 18
Views: 11470

### 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...
Sun May 07, 2017 10:05 am UTC
Forum: Mathematics
Topic: Halting Problem
Replies: 208
Views: 44582

### 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...
Fri Apr 14, 2017 4:52 pm UTC
Forum: Site/Forum issues
Topic: Incorrect encoding on JSONP API
Replies: 5
Views: 9363

### 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 carefulâit's breeding season, and some of these can be *extremely* defensive of their nests.",`

BTW, this bug was mentioned on Stack Overflow Meta.
Tue Apr 11, 2017 9:22 am UTC
Forum: Coding
Topic: Getting the most recent comic
Replies: 24
Views: 92433

### 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.
Tue Apr 11, 2017 9:14 am UTC
Forum: General
Topic: Date for a comic?
Replies: 3
Views: 6453

### 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...
Mon Apr 03, 2017 4:13 pm UTC
Forum: General
Topic: Lucky Ten Thousand (TIL)
Replies: 13421
Views: 1716442

### 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!
Mon Apr 03, 2017 12:47 pm UTC
Forum: General
Topic: Lucky Ten Thousand (TIL)
Replies: 13421
Views: 1716442

### Re: Lucky Ten Thousand (TIL)

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...
Thu Mar 30, 2017 5:40 pm UTC
Forum: Science
Topic: The Reverse of how colors work: how would it look?
Replies: 6
Views: 3719

### 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...
Wed Mar 22, 2017 5:16 am UTC
Forum: General
Topic: Whetstones and Sharp Knives
Replies: 12
Views: 4900

### Re: Whetstones and Sharp Knives

You may find this recent Cooking Stack Exchange question of interest: Do magnets dull knives?
Sun Mar 19, 2017 3:52 pm UTC
Forum: Coding
Topic: Coding: Fleeting Thoughts
Replies: 9979
Views: 1975344

### 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...
Mon Mar 13, 2017 2:03 am UTC
Forum: Language/Linguistics
Topic: Miscellaneous language questions
Replies: 590
Views: 116907

### Re: Miscellaneous language questions

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

Another old term from the days of coal ash is "ashcan".
Fri Mar 10, 2017 7:19 am UTC
Forum: Computer Science
Topic: A Compact Sized "Why?-BOOM" machine.
Replies: 7
Views: 7396

### 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...
Fri Mar 10, 2017 6:50 am UTC
Forum: Science
Topic: Free Will
Replies: 161
Views: 24853

### 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?

Thu Feb 16, 2017 8:28 am UTC
Forum: Mathematics
Topic: "There is an Exception to every rule"
Replies: 32
Views: 8893

### 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...
Fri Dec 30, 2016 7:58 am UTC
Forum: Mathematics
Topic: Combinatoric commanders
Replies: 6
Views: 2830

### 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...
Thu Dec 29, 2016 12:23 pm UTC
Forum: Mathematics
Topic: Combinatoric commanders
Replies: 6
Views: 2830

### 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...
Thu Dec 29, 2016 9:59 am UTC
Forum: Coding
Topic: Coding: Fleeting Thoughts
Replies: 9979
Views: 1975344

### 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...
Wed Dec 28, 2016 7:40 am UTC
Forum: Coding
Topic: Coding: Fleeting Thoughts
Replies: 9979
Views: 1975344

### 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...
Wed Dec 28, 2016 7:29 am UTC
Forum: Computer Science
Replies: 120
Views: 61449

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...
Wed Dec 28, 2016 6:40 am UTC
Forum: Coding
Topic: Coding: Fleeting Thoughts
Replies: 9979
Views: 1975344

### 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...
Fri Nov 25, 2016 8:06 am UTC
Forum: Coding
Topic: Efficiency of prime sieve
Replies: 7
Views: 9512

### 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...
Fri Nov 25, 2016 6:12 am UTC
Forum: Science
Topic: Miscellaneous Science Questions
Replies: 2949
Views: 709464

### 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 ...
Tue Oct 25, 2016 3:54 am UTC
Forum: Mathematics
Topic: Primes under different moduli
Replies: 4
Views: 2855

### 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.
Mon Sep 05, 2016 2:56 pm UTC
Topic: 1729: "Migrating Geese"
Replies: 33
Views: 8384

### Re: 1729: "Migrating Geese"

I was hoping for a Hardy–Ramanujan reference for this one. Oh well.
Fri Sep 02, 2016 1:32 pm UTC
Topic: 1727: "Number of Computers"
Replies: 35
Views: 8060

### Re: 1727: "Number of Computers"

Going sorta off topic, I've always wondered why you couldn't take radioactive waste, mix it with a lot on concrete, and pump it back into the mine it came out of (or any other conveniently depleted mine for that matter). I mean, it was just as radioactive overall before you took it out of the groun...
Fri Sep 02, 2016 3:20 am UTC
Forum: Mathematics
Topic: How to Calculate Pi without a Calculator?
Replies: 66
Views: 13880

### Re: How to Calculate Pi without a Calculator?

Yeah, I'm on my phone (and was between classes at that point), so it would be faster for you to just google "square root long division algorithm" than for me to do it and then go to the resulting page, copy the url, and try to paste it here (I say "try" because my phone often ha...
Wed Aug 31, 2016 12:42 pm UTC
Topic: 1727: "Number of Computers"
Replies: 35
Views: 8060

### Re: 1727: "Number of Computers"

Adjusting the frame of reference yields hurling Jupiter into the Sun. This does not particularily help. We've discussed that too. Would it be possible for humans to pollute the sun? As that thread mentions, if you could somehow collect the entire solar output for 2 billion years or so it would be e...
Wed Aug 31, 2016 6:55 am UTC
Topic: 1727: "Number of Computers"
Replies: 35
Views: 8060

### Re: 1727: "Number of Computers"

What Pfhorrest said. FWIW, here's an old thread about just how hard it is to throw stuff into the Sun: Sun as final storage for radwaste?.
Mon Aug 29, 2016 2:50 am UTC
Topic: 1720: "Horses"
Replies: 55
Views: 11797

### Re: 1720: "Horses"

Mahnarch wrote:I first read that as "safety feathers", and now I'm picturing a car crashing and it looking like a bird exploding from it.

Horse Feathers
Sat Aug 27, 2016 6:04 pm UTC
Forum: Mathematics
Replies: 148
Views: 18142

The philosopher / mathematician / poet Giordano Bruno, who promoted & extended the Copernican theory, was burned at the stake.
Thu Aug 25, 2016 4:32 pm UTC
Forum: General
Topic: Lucky Ten Thousand (TIL)
Replies: 13421
Views: 1716442

### Re: Today I Learned

Today I learned: My peach tree is a nectarine tree. Peach are fuzzy. Nectarine are bald. They are the same species, fuzziness is controlled by a single allele (gene) which can signify either the fuzzy or the non-fuzzy type. The fuzzy type is dominant, so if the DNA of the tree has a pair of genes f...
Tue Aug 23, 2016 2:23 am UTC
Forum: Mathematics
Topic: How to Calculate Pi without a Calculator?
Replies: 66
Views: 13880

### Re: How to Calculate Pi without a Calculator?

A convenient way to calculate decimal digits of pi without a calculator is to use the Taylor series for arctangent with formula 24 on the Mathworld page of Machin-like formulas : pi / 4 = 8 atan(1/10) - atan(1/239) - 4 atan(1/515) This formula is nice to work with for manual calculation because of t...
Mon Aug 22, 2016 3:50 am UTC
Forum: Language/Linguistics
Topic: Words you think English should have or bring back.
Replies: 643
Views: 166601

### Re: Words you think English should have or bring back.

Why do people call their motorcycle a bike? Shouldn't they call it a moke? No, because this is a Moke. https://upload.wikimedia.org/wikipedia/commons/thumb/1/1f/Moke02.png/280px-Moke02.png The name comes from "Mini"—the car with which the Moke shares many parts—and "Moke", which...
Thu Aug 11, 2016 4:05 pm UTC
Forum: Mathematics
Topic: Math: Fleeting Thoughts
Replies: 434
Views: 151803

### Re: Math: Fleeting Thoughts

(I promise I won't ask about properties of these constructions in non-Eucledian space :P ) Oh, in hyperbolic space it's a piece of cake. Remember that in non-Euclidean geometries the angle sum of a triangle isn't constant but instead is a linear function of the area. In hyperbolic space the sum is ...