999999999999999 - 999999999999997 • Hacker News Board

Re: 999999999999999 - 999999999999997

#41

Post by nostrademons » Mon, Aug 24, 2009, 8:28 PM UTC

mid wrote: post #33

_cbsz wrote: post #3

Maybe I'm just getting incurably academic, but I think "I found a bug!" is not nearly as interesting as "I found a bug!" and one of: 1) It affects millions of people! 2) It affects large amounts of money! 3) It is a great example of a new or rare class of bug. Here's how you can avoid introducing similar bugs into your code! Here's how we can detect these things automatically! etc. Here, the only thing that springs t…

BTW, bing does it right: http://www.bing.com/search?q=999999999999999+-+9999999999999...

Bing gets it wrong if you add enough digits:

http://www.bing.com/search?q=999999999999999999999999999+-+9...

Re: 999999999999999 - 999999999999997

#42

Post by bd » Mon, Aug 24, 2009, 8:28 PM UTC

randallsquared wrote: post #36

jacquesm wrote: post #34

Earlier quoted context omitted.

Impressive. I find that extremely hard, it's like things play on an internal monitor that I'm forced to watch and can not ignore no matter how much I want to. I run a webcam site and over the years we've had some pretty weird stuff happening there and I really wished I had not seen any of that.

Unfortunately, I cannot tell you exactly how to develop this ability, because I only discovered I had it by trying, but I remember not having the ability to NOT think about a pink elephant, so it can be developed. Somehow. :) Edit: Apparently rms knows how; see his comment.

Just imagine you are Searle's "Chinese room" :).

http://en.wikipedia.org/wiki/Chinese_room

Re: 999999999999999 - 999999999999997

#43

Post by jballanc » Mon, Aug 24, 2009, 8:37 PM UTC

tripa wrote: post #12

jacquesm wrote: post #11

Earlier quoted context omitted.

Clearly someone wasn't using 'bignum' when they should have. Pretty sloppy to not even detect overflow on the input. another one: http://www.google.com/#q=999999999999999999+-+90000000000000...

It's not really overflow. It's more like insufficient precision.

...also known as Arithmetic underflow (http://en.wikipedia.org/wiki/Arithmetic_underflow)

Re: 999999999999999 - 999999999999997

#44

Post by unalone » Mon, Aug 24, 2009, 8:37 PM UTC

jacquesm wrote: post #34

randallsquared wrote: post #32

Earlier quoted context omitted.

The ability to ignore and avoid thinking about certain things is essential when visiting 4chan. If you practice, you can read sentences like the above without having mental images of the described event. More advanced filters can prevent you from thinking about it with imagery even after seeing something you wish you hadn't seen. ;)

Impressive. I find that extremely hard, it's like things play on an internal monitor that I'm forced to watch and can not ignore no matter how much I want to. I run a webcam site and over the years we've had some pretty weird stuff happening there and I really wished I had not seen any of that.

It's a combination of ignorance and desensitization. My generation grew up with tubgirl and 2girls1cup. I first saw tubgirl/lemon party when I was 13. When I was I think 17, I came across goatse for the first time; by then, a man * his wide wasn't enough to faze me.

I wrote an essay about how this widespread desensitization will affect society and culture. It'll be interesting to see the world in twenty years.

Re: 999999999999999 - 999999999999997

#45

Post by _cbsz » Mon, Aug 24, 2009, 8:39 PM UTC

RyanMcGreal wrote: post #8

In Python: >>> 999999999999999 - 999999999999997 2L

The bug, in Python (needs more digits because Python's "float" is C's "double"):

    >>> float(999999999999999999) - float(999999999999999997)
    0.0

Re: 999999999999999 - 999999999999997

#46

Post by DanielStraight » Mon, Aug 24, 2009, 8:39 PM UTC

_cbsz wrote: post #3

Maybe I'm just getting incurably academic, but I think "I found a bug!" is not nearly as interesting as "I found a bug!" and one of: 1) It affects millions of people! 2) It affects large amounts of money! 3) It is a great example of a new or rare class of bug. Here's how you can avoid introducing similar bugs into your code! Here's how we can detect these things automatically! etc. Here, the only thing that springs t…

I agree. My first thought was "who cares?" After reading all the comments, my thought was "who cares?" Now, my thought is "who cares?"

Re: 999999999999999 - 999999999999997

#47

Post by sp332 » Mon, Aug 24, 2009, 8:48 PM UTC

eru wrote: post #40

apotheon wrote: post #20

Earlier quoted context omitted.

. . . but it's copyrighted, so you're not allowed to tell anyone.

That's fair use.

As long as it's 4 words or less http://news.ycombinator.com/item?id=737986 :)

Re: 999999999999999 - 999999999999997

#48

Post by joubert » Mon, Aug 24, 2009, 8:50 PM UTC

Obviously not using Lisp on the back-end.

Re: 999999999999999 - 999999999999997

#49

Post by [deleted] » Mon, Aug 24, 2009, 9:04 PM UTC

bdr wrote: post #7

_cbsz wrote: post #3

Maybe I'm just getting incurably academic, but I think "I found a bug!" is not nearly as interesting as "I found a bug!" and one of: 1) It affects millions of people! 2) It affects large amounts of money! 3) It is a great example of a new or rare class of bug. Here's how you can avoid introducing similar bugs into your code! Here's how we can detect these things automatically! etc. Here, the only thing that springs t…

What about: 4) It's not obvious how this bug could happen! Let's think about it!

[deleted]

Re: 999999999999999 - 999999999999997

#50

Post by wlievens » Mon, Aug 24, 2009, 9:06 PM UTC

tripa wrote: post #12

jacquesm wrote: post #11

Earlier quoted context omitted.

Clearly someone wasn't using 'bignum' when they should have. Pretty sloppy to not even detect overflow on the input. another one: http://www.google.com/#q=999999999999999999+-+90000000000000...

It's not really overflow. It's more like insufficient precision.

The correct term is quantization, iirc.