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| 2025-11-21 05:44:30 +0100 | merijn | (~merijn@host-vr.cgnat-g.v4.dfn.nl) merijn |
| 2025-11-21 05:40:47 +0100 | <EvanR> | exact real numbers, yes |
| 2025-11-21 05:40:33 +0100 | <EvanR> | chromoblob, this is false for floats, and is the correct thing to do in some cases |
| 2025-11-21 05:40:13 +0100 | <EvanR> | attempting to use math on a computer is a source of errors in programs. avoidance recommended |
| 2025-11-21 05:40:04 +0100 | <chromoblob> | you should never test "real" numbers for equality, it's not meaningful in computers |
| 2025-11-21 05:40:02 +0100 | <jreicher> | That's really interesting. I object to it on mathematically purist grounds, which I'm only half-serious about, but that actually looks like it matters. |
| 2025-11-21 05:38:53 +0100 | <fgarcia> | a source of errors in programs, if software developers do not take into account that while the two zero representations behave as equal under numeric comparisons, they yield different results in some operations." |
| 2025-11-21 05:38:51 +0100 | <fgarcia> | "It is claimed that the inclusion of signed zero in IEEE 754 makes it much easier to achieve numerical accuracy in some critical problems, in particular when computing with complex elementary functions. On the other hand, the concept of signed zero runs contrary to the usual assumption made in mathematics that negative zero is the same value as zero. Representations that allow negative zero can be |
| 2025-11-21 05:38:26 +0100 | <fgarcia> | i think wikipedia has some writing about this |
| 2025-11-21 05:38:09 +0100 | <geekosaur> | losing the "negative" switches which quadrant you're in |
| 2025-11-21 05:38:05 +0100 | Pseudonym | (~Pseudonym@194-223-46-47.tpgi.com.au) Pseudonym |
| 2025-11-21 05:37:55 +0100 | <EvanR> | by the same logic negative NaN accomplishes the same thing |
| 2025-11-21 05:37:54 +0100 | <geekosaur> | fgarcia, yes, and it happens when you're working with trig functions in a plane |
| 2025-11-21 05:37:11 +0100 | <EvanR> | so you end up with partial information |
| 2025-11-21 05:37:11 +0100 | <geekosaur> | as apparently has libtommath which was my first idea (then found something pointing to bsdnt instead) |
| 2025-11-21 05:37:05 +0100 | werneta | (~werneta@71.83.160.242) (Quit: Lost terminal) |
| 2025-11-21 05:36:42 +0100 | <EvanR> | a negative zero happens when a computation would be negative but too small to represent |
| 2025-11-21 05:36:40 +0100 | <geekosaur> | actually it was bsdnt, which seems to have disappeared |
| 2025-11-21 05:34:59 +0100 | <fgarcia> | i am not smart. would they have thought it would be somehow useful for limits approaching from >0 and <0 ? |
| 2025-11-21 05:34:50 +0100 | <EvanR> | whatever you need to do do it in the range 1 <= x < 2 |
| 2025-11-21 05:33:52 +0100 | merijn | (~merijn@host-vr.cgnat-g.v4.dfn.nl) (Ping timeout: 256 seconds) |
| 2025-11-21 05:33:47 +0100 | <EvanR> | or any kind of zero for that matter |
| 2025-11-21 05:33:40 +0100 | <EvanR> | for numbers of the form mantissa times 2^e signed zero isn't a thing xD |
| 2025-11-21 05:32:45 +0100 | <EvanR> | lol |
| 2025-11-21 05:32:40 +0100 | <jreicher> | Signed zero in the first place should not be a thing. :( |
| 2025-11-21 05:32:09 +0100 | Shark8 | (~Shark8@c-174-56-102-109.hsd1.nm.comcast.net) (Ping timeout: 244 seconds) |
| 2025-11-21 05:31:57 +0100 | marlino | (~marlino@96-8-193-95.block0.gvtc.com) (Quit: WeeChat 4.7.1) |
| 2025-11-21 05:31:50 +0100 | <EvanR> | they should have made a signed NaN in case you divide negative zero by zero |
| 2025-11-21 05:31:18 +0100 | <EvanR> | that be the realm of float "logic" |
| 2025-11-21 05:31:04 +0100 | <jreicher> | But it is a number. You just don't know which one. :p |
| 2025-11-21 05:30:51 +0100 | <fgarcia> | oh, somewhere i have written 0.0 / 0.0 because i wanted Not a Number as a result |
| 2025-11-21 05:30:27 +0100 | <EvanR> | lol |
| 2025-11-21 05:30:22 +0100 | <chromoblob> | <s>0.5</s> |
| 2025-11-21 05:30:17 +0100 | <EvanR> | it should clearly be 7 because this one time that would make sense |
| 2025-11-21 05:30:06 +0100 | <geekosaur> | haven't really had time to work on it though |
| 2025-11-21 05:29:57 +0100 | <jreicher> | EvanR what should it be? (I'm not saying it should be 0; I'm just curious what you think) |
| 2025-11-21 05:29:39 +0100 | <geekosaur> | Zemyla, I actually started work on that (adding bsdmp as a backend), but decided it would be easier to port its multiplication optimizations than to work around its violation of ghc bignum invariants |
| 2025-11-21 05:29:33 +0100 | <EvanR> | 0 / 0 = 0 |
| 2025-11-21 05:29:28 +0100 | <jreicher> | EvanR what's the nonsense result? |
| 2025-11-21 05:29:25 +0100 | <EvanR> | if you are going to make it total make it total really and define all behavior |
| 2025-11-21 05:29:14 +0100 | Dhark8 | (~Shark8@c-174-56-102-109.hsd1.nm.comcast.net) |
| 2025-11-21 05:29:01 +0100 | merijn | (~merijn@host-vr.cgnat-g.v4.dfn.nl) merijn |
| 2025-11-21 05:28:59 +0100 | <EvanR> | it is "interesting" that you would mix a nonsense result on one hand with undefined behavior on the other |
| 2025-11-21 05:28:52 +0100 | <haskellbridge> | <Zemyla> x / 0 should be 0 if division is total, because 0 is the pseudoinverse of zero. The pseudoinverse of x is y such that xyx = x and yxy = y. |
| 2025-11-21 05:27:47 +0100 | <chromoblob> | i mean, in integer division |
| 2025-11-21 05:27:29 +0100 | <chromoblob> | AArch64 gives you 0 as result of division by zero. i also wanted to make it like this in my language (because dividing 0 by anything gives 0, so 0 / 0 should be 0 too, and since x / 0 for x ≠ 0 is undefined, might as well just check for dividend = 0, regarding other cases as UB) |
| 2025-11-21 05:24:01 +0100 | <fgarcia> | :D |
| 2025-11-21 05:22:39 +0100 | <EvanR> | Divide by zero -- You can't divide by zero on a computer. Some kind of math thing. Don't worry too much about understanding why. Just don't do it. (EXAPUNKS zine 1 page 12) |
| 2025-11-21 05:20:45 +0100 | Googulator96 | (~Googulato@2a01-036d-0106-0231-4475-80b4-5cdc-43d6.pool6.digikabel.hu) (Quit: Client closed) |
| 2025-11-21 05:20:44 +0100 | Googulator46 | (~Googulato@2a01-036d-0106-0231-4475-80b4-5cdc-43d6.pool6.digikabel.hu) |