egg|nomz|egg changed the topic of #kspacademia to: https://gist.github.com/pdn4kd/164b9b85435d87afbec0c3a7e69d3e6d | Dogs are cats. Spiders are cat interferometers. | Космизм сегодня! | Document well, for tomorrow you may get mauled by a ネコバス. | <UmbralRaptor> egg|nomz|egg: generally if your eyes are dewing over, that's not the weather. | <ferram4> I shall beat my problems to death with an engineer.
<bofh>
Hm, might still suffice.
<bofh>
oh it's in an earth-trailing orbitvw/perihelion 1.003au & aphelion 1.026au? yeah 8m is plenty w/a good klystron.
<bofh>
I thought it was at Earth-Sun L2 for some reason.
<bofh>
(oh, prolly b/c WFIRST is planned to go there)
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<bofh>
!u abuse̊̊
<Qboid>
U+0061 LATIN SMALL LETTER A (a)
<Qboid>
U+0062 LATIN SMALL LETTER B (b)
<Qboid>
U+0075 LATIN SMALL LETTER U (u)
<Qboid>
U+0073 LATIN SMALL LETTER S (s)
<Qboid>
U+0065 LATIN SMALL LETTER E (e)
<Qboid>
U+030A COMBINING RING ABOVE (◌̊)
<Qboid>
U+030A COMBINING RING ABOVE (◌̊)
<UmbralRaptor>
!u 🐛💙
<Qboid>
U+1F41B BUG (🐛)
<Qboid>
U+1F499 BLUE HEART (💙)
<UmbralRaptor>
Anyway, scutigera look terrifying.
<egg|zzz|egg>
awang: dunno, ask richard about those UB implications
* egg|zzz|egg
stabs WG 21 in the poor wording
<egg|zzz|egg>
WG 9 FTW!
<egg|zzz|egg>
"The elaboration of a formal part has no other effect."
<egg|zzz|egg>
bofh: other amusing Ada tidbit: back in 1983, international standards had to be in at least two languages, so there is a french version of the reference manual (sadly it doesn't appear to exist online)
<egg|zzz|egg>
bofh: also, yup, the Rational R1000 had addressable bits (the addresses were 67 bits (byte addresses segmented 32+32 and bits with the last 3), which wasn't much of a problem since you weren't trying to align with anything :-p)
<egg|zzz|egg>
bofh: which is unfortunately not something you can represent in C since CHAR_BIT cannot be 1
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<jvekstrem-extrem>
чёт мало
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<awang>
egg|zzz|egg: Never mind, I see why it's not UB. Pointers to the old storage can still be used for comparisons
<kmath>
<✔GretchenAMcC> Hey nostalgia internet, anyone want to tell me the names of some classic listservs or IRC channels that you used to really enjoy?
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<egg|phone|egg>
Awang: pointer comparisons? But you don't care about the vtable for that?
<awang>
egg|phone|egg: Don't think so?
<awang>
The example they gave was something along the lines of
<awang>
A* a = new A;
<awang>
a->foo();
<awang>
A* b = new(a) B;
<awang>
if (a == b)
<awang>
b->foo();
<awang>
Or wait
<awang>
Yeah
<awang>
I'm confusing myself
<awang>
Not sure if the standard says what should happen here
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<awang>
The `a` pointer doesn't get "redirected" to point to B, since the new object isn't the same type as the original
<awang>
Standard also says that `a` can be treated as a void* after the lifetime of A has ended, but before its storage is reused
<awang>
At least on an intuitive level, the new(a) B counts as reusing storage
<awang>
So I'm not sure (a == b) is valid
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<bofh>
)/win 26
<egg|work|egg>
bofh: the 2026 version of Windows?
<egg|work|egg>
awang: even if it does, you're not accessing foo via a after the pawcement mew
* UmbralRaptor
mrows at egg|work|egg?
* egg|work|egg
pets UmbralRaptor
<egg|work|egg>
!wpn UmbralRaptor
* Qboid
gives UmbralRaptor a transverse gauntlet
<UmbralRaptor>
!wpn egg|work|egg
* Qboid
gives egg|work|egg a prescriptive tensor/package hybrid
<awang>
egg|work|egg: I guess?
<awang>
Is a considered dangling after the placement new?
<awang>
SO says comparing dangling pointers is implementation-defined behavior, so if a is dangling then the comparison is alright
<whitequark>
awang: i'm not sure if SO is correct here
<awang>
And seems a isn't dangling after the placement new?
<awang>
It's dangling only after deallocation
<whitequark>
yes
<whitequark>
afaiu
<awang>
Hmmm
<awang>
Guess the comparison is valid then
<awang>
If comparing dangling pointers is ok, being able to compare a pointer to reused storage would make sense
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<awang>
!wpn -add:wpn Y combinator
<Qboid>
awang: Weapon added!
* UmbralRaptop
pokes Title IX training with a stick.
<UmbralRaptop>
…oh, hey, there's a section on consensual relationships.
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* UmbralRaptop
wonders if this is going to involve explaining that he's probably to broken to maintain a romantic relationship, so that section is mostly theoretical.
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<awang>
I used to be a "tabs for indentation, space for alignment" guy
<awang>
Starting to lean towards spaces-only after working with people whose editors aren't consistent for one reason or another
<awang>
vim .clang-format
<awang>
Er
<awang>
Wrong window
<awang>
Sorry
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<UmbralRaptop>
Editors where you hit tab, and it's stochastic as to if you get \t, some spaces, or a mix?
<kmath>
<fugueish> Me: Oh, good! Thanks. Now I can go back to singing the C++ Theme Song. ⏎ ⏎ Colleague: What's the C++ theme song? ⏎ ⏎ Me:… https://t.co/OPFSFMyLw3
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<awang>
UmbralRaptor: idk, the other guy's commits somehow manage to have both mixed in. No idea how
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* awang
🔪
<awang>
.....
* awang
🔪
<awang>
............
<awang>
Forget it
<UmbralRaptop>
Yay, 🔪
* awang
🔪 cothe clipboard
* awang
🔪 terminals that can't handle wide characters
* awang
🔪 clang-format
* UmbralRaptop
suggests 🔥 for dealing with C-compilers.
* awang
💣 everything
<UmbralRaptop>
Please do not 💥 the 🐍.
* awang
places 🐍. in bomb shelter
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<egg|work|egg>
awang: yes, but I'm not sure what that has to do with the vtable optimization; you can compare the old pointer, but not do much with its dereferencing
<egg|work|egg>
bofh: what's the principia-style C++ song
<awang>
egg|work|egg: Apparently the vtable optimization is part of a larger devirtualization effort, and it was the placement new thing that was holding up the devirtualization optimization
<egg|work|egg>
pawcement mew
<egg|work|egg>
!wpn whitequark
* Qboid
gives whitequark a solipsistic স্রু
<egg|work|egg>
!u স্রু
<Qboid>
U+09B8 BENGALI LETTER SA (স)
<Qboid>
U+09CD BENGALI SIGN VIRAMA (◌্)
<Qboid>
U+09B0 BENGALI LETTER RA (র)
<Qboid>
U+200C ZERO WIDTH NON-JOINER ()
<Qboid>
U+09C1 BENGALI VOWEL SIGN U (◌ু)
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<UmbralRaptop>
egg: It turns out that cursed runes are possible in Indo-european languages.
<awang>
So clang-format thinks that '^<.*[A-Z0-9.].*>$' matches <vector>
<awang>
Just...
<awang>
how
<egg|work|egg>
case-insensitive matching?
<UmbralRaptop>
Literally fake news; Bennu makes a close encounter in 2135, but does not impact. The study intentionally changes the ephemeris slightly so that Bennu would pass through the center of Earth then.
<egg|work|egg>
awang: what is this regex supposed to find
<SnoopJeDi>
yea that looks like case-insensitivity to me
<SnoopJeDi>
OH WAIT, no
<SnoopJeDi>
nvm, '.' is not semantically special in []
<awang>
egg|work|egg: Supposed to find <> headers that contain a capital letter or digit
<bofh>
UmbralRaptop: what's the relevant cursed Indo-European rune?
* SnoopJeDi
goes back to sipping coffee
<awang>
i.e. not STL headers
<UmbralRaptop>
the .* part?
<awang>
I thought the [A-Z0-9.] part means there *must* be a capital letter or digit
<awang>
Or period
<SnoopJeDi>
it does because it's not quantified
<egg|work|egg>
if the matching is case-sensitive
<SnoopJeDi>
although .* isn't a great thing to wrap there because <> are part of .
<UmbralRaptop>
bofh: what egg got. (স্রু)
<SnoopJeDi>
should probably be [^>]* instead
<SnoopJeDi>
relatedly, awang are there capital letters or numbers elsewhere on the line?
<awang>
Oh come on, I need to recompile for case-sensitive matching?
<SnoopJeDi>
interestingly, it looks like there was actually opposition to a flag?
<SnoopJeDi>
anyway it looks like the main change is L1412 in Format.cpp
<awang>
"I don't think anyone is relying on the current behavior."
<awang>
:(
<awang>
Yeah, I see it
<SnoopJeDi>
uh and I guess also 1444
<awang>
There goes my super-clever way of picking out actual STL headers from system headers
<SnoopJeDi>
lol that last snarky comment
<awang>
Yeah
<awang>
Looks like I'm going to have to figure out how to hack LLVM
<SnoopJeDi>
A good start would be the initial version of that commit that *did* have a flag
<SnoopJeDi>
dunno if you'd have anyway of applying pressure on getting that upstream, but two people saying "uh yep I needed this and you broke it" should be evidence enough imo. Dunno how provincial LLVM's community is.
<awang>
Not really sure if what I want case-sensitivity for is considered too trivial
<awang>
Since it probably isn't correct anyways
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<APlayer>
Humm, Ellied, got a few minutes?
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<APlayer>
Ellied: Let me just state the issue, and you can highlight me whenever you find the time and will.
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<APlayer>
So, I have an Arduino Pro Mini and a GY-91 sensor (https://i.ebayimg.com/images/g/UJ4AAOSwjkVZg4DO/s-l1600.jpg). They should communicate via I2C, but they don't. In tracking down the problem, I found out that Arduino's Wire library hangs the script on calling Wire.endTransmission().
<SnoopJeDi>
APlayer, it's usually good netiquette to do so when communicating asynchronously, lest you end up playing ping-tag.
<APlayer>
Inspecting the hardware, it seems to be fine, both components have lit LEDs (I guess they are powered properly and not fried, then), SCL is connected to Arduino pin A5, SDA is connected to Arduino pin A4 and both lines have a 4.7 kOhm pull-up to 5V.
<APlayer>
And that's basically where I am stuck, because I have no idea what to do next - how can I troubleshoot this? Or do you already have an idea of what might be going on?
<APlayer>
SnoopJeDi: I guess, yes. Thank you for the general advice, I am still kind of new to IRC netiquette (that's not where your parents teach you what to do...)
<SnoopJeDi>
it's definitely almost always good netiquette on IRC in channels like #programming or whathaveyou as long as the messages don't disrupt a channel.
<SnoopJeDi>
i.e. instead of "anyone familiar with X?" you can go with "Hi, I'm looking for help doing Y with X. I've read the docs and thought it could be done via Z, but I get error W. Can anyone help?"
<APlayer>
I tend to ask if anyone is available to answer my question, because otherwise chances are I will type it out (which was not little in this case) and noone has an idea. In this case I guess I should have typed it out immediately, though, because the channel is not busy enough for the message to get lost, and I am 90% sure the person has at least some advice for me.
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<APlayer>
Also, I actually have read this page at some point in my interneducation
<APlayer>
I guess I should re-read it one day, though
<SnoopJeDi>
it's definitely murkier in a closer-knit channel like this one, I didn't mean to chastise you :)
<APlayer>
Oh, no, you didn't! :-) I just acknowledge netiquette is a somewhat weak point of mine, and that I should re-read the article (I am actually doing this right now)
<APlayer>
Also, I was told a few times not to "ask to ask" but some part of me just refuses to learn some basic social interaction rules. This is not the only thing I keep doing wrong
<SnoopJeDi>
yea, I hear you. I usually flesh out those requests with some context and "can I pick your brain" or somesuch if I mean a specific person.
<SnoopJeDi>
I would never send an email asking-to-ask, for example.
<SnoopJeDi>
but kspacademia is nice in part because of the abundance of politeness
<e_14159>
SnoopJeDi: I'd make a joke involving profanity, but I really don't want to.
<e_14159>
I hope this meta-joke is acceptable instead.
<egg|zzz|egg>
e_14159: meow?
<egg|zzz|egg>
!wpn e_14159
* Qboid
gives e_14159 a meowing theory of everything
<egg|zzz|egg>
!wpn u
* Qboid
gives u a calcium hummingbird-like paint
<egg|zzz|egg>
uh
<e_14159>
egg|zzz|egg: o_O
<egg|zzz|egg>
no raptor?
<e_14159>
Did you hack Qboid?
<egg|zzz|egg>
!wpn Raptop
* Qboid
gives Raptop a ksh-compatible pen
<egg|zzz|egg>
e_14159: no
<egg|zzz|egg>
Qboid just likes cats apparently
<e_14159>
In that case it was an amusing catincidence.
<egg|zzz|egg>
!wpn bofh
* Qboid
gives bofh a vector anticommutator
<Thomas>
!wpn cat
* Qboid
gives cat a Колмогоров hull-like reflector
<egg|zzz|egg>
from a guess of ceiling(dividing the exponent) you get to the point where you'd need to start thinking about the last few ULPs and extra precision in four iterates for cbrt through 5th root in binary64, instead of 7 with Newton cbrt and moe for higher roots
<egg|zzz|egg>
s/moe/more/ even
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<bofh>
egg|zzz|egg: yep, I use it in my cbrt code for exactly this reason.
<egg|zzz|egg>
bofh: oh you have your own cbrt?
<egg|zzz|egg>
bofh: also ceiling(divide the exponent) is a surprisingly decent guess
<bofh>
it's literally "grab exponent, div-by-3, correct for the fractional exponent part (a single multiply), 5 iterates of Halley".
<bofh>
I can dig it up later when I'm on my laptop at home instead of my office machine.
<egg|zzz|egg>
5 iterates? are you doing extended precision madness?
<egg|zzz|egg>
hm maybe 4 still has a few stray bits missing
<egg|zzz|egg>
so I guess you run the 5th iterate For a Few ULPs More
<bofh>
egg|zzz|egg: sorry I was misremembering, I think I did 4. I'll double-check the code.
<bofh>
but yeah I think you might need 5 in all cases. m.
<bofh>
hm*
<egg|zzz|egg>
bofh: although you could always do a sixth in double-double, who wouldn't want correct-rounded cbrt
<egg|zzz|egg>
s/ct/ctly
<Qboid>
egg|zzz|egg meant to say: bofh: although you could always do a sixth in double-double, who wouldn't want correctly-rounded cbrt
<bofh>
(actually I think what I did was computed I needed 4 according to simple error analysis and did an extra For A Few ULPs More, indeed).
<kmath>
<DrAstroStu> Done for now, time to recuperate before #LPSC2018 marathon poster session ... and I'm not even presenting tonight.… https://t.co/IW1tMSEQ9T