Jeff Atwood Answers and Square Roots



  • If you had a magic wand to make one change in technology right now, what would it be?
    http://i.imgur.com/SglRVEH.png




  • And now Jeff has provided non-answers to the non-questions that were carefully selected by the retarded chimpanzees at Slashdot.

    Files under: With apologies to the retarded chimpanzees of the world




  • area_deu

    And this shows once again how Jeff == SO/SE
    Even though he left some time ago.



  • Yes. i know. that's why i started this thread, with a link to his answers.



  • He's generally right about the passwords though.

    Remember that Stack is for questions that can be explicitly answered, not discussion. It's not a place for "what's the best way to.." opinion sinkholes.

    So you can't ask for the best way to do X because it involves opinions. Genius. But you can ask for "a way to do X", and then let the votes sort the different ways by popularity, because now it's not discussion-based somehow.



  • Well of course, because asking "what's the best way to do X?" is :doing_it_wrong:



  • All the old talking points rehashed.

    Boring.



  • @aliceif said:

    And this shows once again how Jeff == SO/SE
    Even though he left some time ago.

    Did he leave both SE & SO? The original article said he left SE, but nothing about him leaving SO.

    Most of the questions were about SO, which didn't seem too strange after I noticed that SE !== SO.


  • mod

    @cartman82 said:

    All the old talking points rehashed.

    Yeah, this was a serious softball interview :/



  • @Yamikuronue said:

    Yeah, this was a serious softball interview :confused:

    TDWTF should start doing those interviews.



  • I'm Blakeyrat, ask me anything.



  • @blakeyrat said:

    I'm Blakeyrat, ask me anything.

    What is the air speed velocity of an unladen swallow? And how does it differ from the top speed of a greased rat?


  • Winner of the 2016 Presidential Election

    If you had a magic wand to make one change in technology right now, what would it be?

    Filed Under: Original question, guys! Don't steal!


  • Winner of the 2016 Presidential Election

    [quote=Jeff]
    Having switched to Ruby with the Discourse project, I can also testify that Ruby .. is, uh ... not ... absurdly fast.
    [/quote]



  • He didn't say he would reply, very slashdoty of him



  • So-called "civilized discourse" is some of the blandest, boring, mind-numbing conversation there is. It's completely devoid of original thought. This is because original thought might just hurt somebody's feelings, which is considered totally unacceptable for some reason. Negativity, especially negativity that's the most legitimate and correct, is also not tolerated, again because somebody's feelings might get hurt. Discussion forums where that's the policy quickly become politically correct mutual masturbation sessions, where the mindlessness is repeated again and again. It's funny, though, that the moderators at such communities are often the biggest tyrants around. The louder they scream about how critical it is to be tolerant of others, the faster and harder they'll crack down on anyone who dares to show any sort of originality!



  • I wonder if there would have been a way to figure that out before spending millions of dollars and several years of his life working on a Ruby project...



  • ...yeah, but that would imply he actually listens to others and/or tests things.



  • This is bullshit:

    Remember that Stack is for questions that can be explicitly answered, not discussion. It's not a place for "what's the best way to.." opinion sinkholes

    I like to see different approaches to things. These are super useful questions for peer education, which Jeff claims SE is supposedly about. It's an act of intellectual cowardice IMO to shy away from things that don't have obvious objective answers.



  • @cartman82 said:

    All the old talking points rehashed.

    Yeah, but.....:rage:



  • To be fair, it's the way Ruby works with the DB (and their manual stuff, too) that's the main problem here.



  • I like this bit of a question:

    ...it seems like you are fascinated with filtering out the most useful information.

    Too true. But somehow, I don't think that's what he meant to say. :smile:



  • @boomzilla said:

    to shy away from things that don't have obvious objective answers

    If things have obvious objective answers, why would you even need a website with user input for that? Just make a static website that contains all answers to questions with obvious objective answers. I bet you can fit it in the memory that Discourse uses on the client.



  • @ben_lubar said:

    If things have obvious objective answers, why would you even need a website with user input for that?

    Well, they may not be obvious. And given the typical state of documentation of stuff, this is almost guaranteed! There are plenty of useful questions on SO that answer these questions, and I've certainly benefited from a lot of them.

    @ben_lubar said:

    Just make a static website that contains all answers to questions with obvious objective answers. I bet you can fit it in the memory that Discourse uses on the client.

    OK, that's probably a good point...


  • Discourse touched me in a no-no place

    @loopback0 said:

    > So-called "civilized discourse" is some of the blandest, boring, mind-numbing conversation there is. It's completely devoid of original thought.

    You're invading my safe space, you racist, transphobic rapist, I demand that you resign immediately....


    .. sorry - I simply can't be bothered to carry on - how these students today manage it I've no idea.



  • But any web forum would be good enough for that. Maybe Jeff realized it.



  • @boomzilla said:

    To be fair, it's the way Ruby works with the DB (and their manual stuff, too)the "design" of Discourse that's the main problem here.

    It would be shit in any language.



  • A Q&A site where people can post answers and people can vote on them? It seems made for a "What's the best way" sort of question.



  • @ben_lubar said:

    Just make a static website that contains all answers to questions with obvious objective answers. I bet you can fit it in the memory that Discourse uses on the client.

    What about questions like "What is 1 + 1?", "What is 1 + 2?", ..., "What is "2 + 1?" ...

    Yes, right... it would be discriminating to contract bridge building only to people that share the opinion that two plus two might equal four and nothing else.



  • @boomzilla said:

    A Q&A site where people can post answers and people can vote on them? It
    seems made for a "What's the best way" sort of question.

    But then you might get people asking things like "What is the best way to
    generate a default letter avatar for users?". Having your own community
    tell you that the answer is just about anything but "Make a call to a 3rd
    party API hosted by the discodevs" would be awkward at best. Much better to
    stick to things like "How do I frob the foo in Windows ME?" where there can
    be no chance of answers making people look silly...



  • @PWolff said:

    @ben_lubar said:
    Just make a static website that contains all answers to questions with obvious objective answers. I bet you can fit it in the memory that Discourse uses on the client.

    What about questions like "What is 1 + 1?", "What is 1 + 2?", ..., "What is "2 + 1?" ...

    Yes, right... it would be discriminating to contract bridge building only to people that share the opinion that two plus two might equal four and nothing else.

    What is (square root of 4) - 2

    My Windows calculator says it is -1.068281969439142e-19


  • Grade A Premium Asshole

    @Spanky587 said:

    What is (square root of 4) - 2

    My Windows calculator says it is -1.068281969439142e-19

    Oh, you're on desktop?

    Well, that's different.


  • sockdevs

    @Spanky587 said:

    My Windows calculator says it is -1.068281969439142e-19

    Oh, you're using a Pentium FPU?

    Well, that's different.



  • Bug in Windows calc that has existed for years.

    (1) Take the square root of any number where the result is an integer
    sqrt of 4
    sqrt of 9
    sqrt of 16
    etc . . .

    (2) Subtract any number. You'll get the correct answer,
    UNLESS you subtract a number that SHOULD result in zero.



  • @boomzilla said:

    This is bullshit:

    Remember that Stack is for questions that can be explicitly answered, not discussion. It's not a place for "what's the best way to.." opinion sinkholes

    I like to see different approaches to things. These are super useful questions for peer education, which Jeff claims SE is supposedly about. It's an act of intellectual cowardice IMO to shy away from things that don't have obvious objective answers.

    To be fair, that was the original intent behind Programmers.StackExchange until the powers that be decided to switch horses mid-stream.

    Actually, now that I think about it, it was probably Jeff that decided that, too!



  • @boomzilla said:

    These are super useful questions for peer education, which Jeff claims SE is supposedly about. It's an act of intellectual cowardice IMO to shy away from things that don't have obvious objective answers.

    The users with more StackPointzzzz can use it to wave their StackPeen around at the users without, which I'm pretty sure is the whole point of StackExchange anyway.



  • @PJH said:

    how these students today manage it I've no idea.

    They've not had chance to grow up and experience actual problems yet, presumably.



  • @boomzilla said:

    To be fair, it's the way Ruby works with the DB (and their manual stuff, too) that's the main problem here.

    That's not a Ruby thing, that's their crummy ORM tool.

    I mean, not to say that Ruby is fast. But there's nothing inherent in Ruby preventing it from running stored procedures or adding indexes to tables.



  • @Spanky587 said:

    -1.068281969439142e-19

    @Spanky587 said:
    Subtract any number. You'll get the correct answer,UNLESS you subtract a number that SHOULD result in zero.

    Do people here seriously not understand floating point underflow?



  • @Scarlet_Manuka said:

    @Spanky587 said:
    -1.068281969439142e-19

    @Spanky587 said:
    Subtract any number. You'll get the correct answer,UNLESS you subtract a number that SHOULD result in zero.

    Do people here seriously not understand floating point underflow?

    What is the square root of 4? It is 2. It is EXACTLY 2. It is not 1.999999999999 or 2.000000000001. It is EXACTLY 2, or if you want to use a floating point number it is 2.0000000000000000000000 -> infinite number of zeros.

    If you subtract 2 from 2 and get any answer other than 0, it has nothing to do with "floating point underflow" It is Discourse-level :wtf: programing:



  • Obviously. But the fact that the result of the square root algorithm differs from the exact result by the floating point underflow amount shouldn't be particularly surprising.



  • Really? Because the processor instruction for "square root" gets it right.

    Edit: Actually, how the hell does that happen? You're subtracting something on the order of 1<<1 from something on the order of 1<<1 and getting something on the order of -1>>63. That's 64 bits of mantissa. Doubles only have 52 bits of mantissa.



  • We have a few tricks up our sleeve at Discourse.
    We try to teach communities not just how the software works, but how
    human beings should work, with stuff like our Universal Rules of Civilized Discourse which is prominently featured in every install of Discourse and of course Creative Commons licensed.

    no comments



  • @Jarry said:

    how human beings should work


  • Grade A Premium Asshole

    @Spanky587 said:

    What is the square root of 4? It is 2. It is EXACTLY 2.

    How do you calculate it programmatically? You and I know square roots of lots of perfect squares, computers don't. They calculate square roots. You found an underflow error. No big deal. It happens. Computers have to exit their calculations at some point, or else they could get stuck in a loop getting ever closer to the correct answer, but never quite there.



  • @Polygeekery said:

    How do you calculate it programmatically?

    You use the SQRTSD instruction.

    @Polygeekery said:

    computers don't.

    Yes they do.



  • @ben_lubar said:

    That's 64 bits of mantissa. Doubles only have 52 bits of mantissa.

    Which probably indicates it's not using doubles, so the result of the processor instruction operating on doubles is perhaps not relevant.
    @Wikipedia said:
    In Windows 98 and later, it uses an arbitrary-precision arithmetic library, replacing the standard IEEE floating point library.[2] It offers bignum precision for basic operations (addition, subtraction, multiplication, division) and 32 digits of precision for advanced operations (square root, transcendental functions).

    Incidentally it gives me -8.1648465955514287168521180122928e-39 in scientific mode (I sometimes forget that other modes exist), so it looks like it's doing something like 64 bit precision in standard view and 128 bit in scientific view.



  • @Polygeekery said:

    How do you calculate it programmatically?

    It knew enough to display the value as an int.

    Why didn't it know enough to process the next calculator operation with an int value?

    Sorry, this is a bug. One that has a very easy fix, even if the CPU instruction Ben L mentioned didn't exist. (Or didn't exist at the time Calculator was first written.)


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