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.
<xShadowx>
oh great gods of math, i beseech thou and thy wisdom! - how to calculate (preferably in english or c# :P ) the volume of a complex mesh?
<xShadowx>
everything i find is for simple convex shapes, taking a triangle face and the origin/center of the shape to calc volume of a tetrahedron > repeat for every face
<xShadowx>
but that doesnt work for complex shapes, such as a humanoid :(
<UmbralRaptor>
Have a large graduated tank with water, dunk the human or something into it, note the change in height.
<xShadowx>
sadly its a computer mesh not real human ;p
<xShadowx>
even the plugins im finding for various 3d software goes the simple route so i cant ninja the algorithm ;p
<UmbralRaptor>
I suspect that's all numeric solutions approximating your mesh as a bunch of simpler shapes. Can you create the mesh in a CAD program that will automagically calculate volume?
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<UmbralRaptor>
Arbitrary triple integrals are horrible things that may not always have analytic solutions.
<UmbralRaptor>
"Due to our "Go Green" effort; a card will not be mailed to you automatically."
<UmbralRaptor>
Do they not realize that I'm going to print one out, then?
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<xShadowx>
right now the mesh is just obj, id think any 3d modelling app / most cad stuff could open, ut none of my cad stuff can do volume :|
<xShadowx>
i know its possible to get the volume, because its just a shape made of triangles, and none of them intersect eachother. i can see a possible ish way would be to create multiple 'origin points' and calculate it in chunks, just a lot of writing math that i dont wanna spend a day tweaking to ensure every poly is checked :|
<egg>
!pet котеньку and whitequark
* Qboid
pets котеньку and whitequark
<bofh>
Bienvenue à Ly...okay, Saint-Bonnet-de-Mure, technically (long story).
<egg>
bofh: ... wat
<bofh>
place we were were going to stay decided to bail on dx minutes before we arrived, tried to find a place to stay but literally every hotel in the *city* is booked solid, so now just need to wait until 5AM for the day rollover at some hotels to happen and then dx can get a decent one in downtown at a reasonable price if so desired.
<bofh>
meanwhile I'm just doing what I do best in new and unfamiliar cities, namely wander all around them at 5AM,
<egg>
...
<bofh>
I swear I'm not cursèd,
<egg>
!u è
<Qboid>
U+00E8 LATIN SMALL LETTER E WITH GRAVE (è)
<bofh>
I borrowed that intonation style from kia, okay,
<egg>
bofh: google maps shows a B&B in st bonnet de mure
<egg>
also have you considered: planning things more than an hour in advance,
<kmath>
<AndrewNCassidy> if you need me I'm reading sales pages for gas chromatographs
<UmbralRaptor>
;8ball is writing a Python script to generate a bunch of config files that will then be used by a shell script the worst Zachtronics game?
<kmath>
UmbralRaptor: Outlook not so good
<iximeow>
UmbralRaptor: ...
<UmbralRaptor>
iximeow: I, uh, need to do one-off planet fits on radial velocity data for 54 stars (which will probably expand to 880)
<UmbralRaptor>
It's not like I'm doing anything with networking or logins.
<UmbralRaptor>
Or anything that needs to update x times a second. >_>;;
* X
updates
* X
updates
* X
updates
<UmbralRaptor>
X: sudo apt-get dist-upgrade
<X>
=\ I don’t have that distro
<SnoopJeDi>
UmbralRaptor, can't migrate the fits into Python? >:)
<SnoopJeDi>
or more likely not worth doing heh
<UmbralRaptor>
SnoopJeDi: well, the shell script is pretty much just telling radvel† to do various things to 54 stars.
<UmbralRaptor>
†radvel is written in python.
<SnoopJeDi>
ooh, I didn't know about radvel
<SnoopJeDi>
I mean not that I would, but might be worth plopping onto my one astropy slide
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<egg|phone|egg>
!meow bofh dx
* Qboid
meows at bofh dx
xShadowx has quit [Read error: Connection reset by peer]
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<dx>
hiii
<dx>
egg: so i just left bofh
<dx>
she still has her laptop to connect here from time to time but from now on it's mostly all phoneless wandering
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<bofh>
dx: so like you know that's not at all a problem for me, right,
<bofh>
the primary issue is that it's *CAMERA*less wandering.
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<bofh>
!meow egg
* Qboid
meows at egg
<egg>
bofh: okay so now I'm getting spam about TGV INOUI
<bofh>
egg: what the actual fuck
<egg>
bofh: well usually i get lyria spam
<bofh>
egg: so bizarrely I've yet to get a single article of spam from Thalys.
<bofh>
and I've gotten spam from the lost items desk at Gare Saint-Lazare ffs.
<kmath>
<whitequark> OH': "i tried to explain to the chief architect of DOCSIS what "boneless" means"
<bofh>
<<<<<Bonjour Peter BARFUSS,
<bofh>
Vous venez de réaliser votre déclaration de perte d'objet portant sur la référence O-201809-01270017.
<bofh>
Afin de vous garantir la plus grande satisfaction et vous accompagner au mieux, partagez-nous votre expérience, via ce questionnaire en ligne. Il ne vous suffit que de trois minutes pour y répondre !
<bofh>
like, seriously, it's spam from the lost items desk at Gare Saint-Lazare. >_>
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<dx>
bofh:
<dx>
06:59 < vague> There is a dance festival in Lyon until Sunday
<dx>
07:00 < vague> The 18th International Dance Biennale
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<UmbralRaptor>
Yes, let's make up for being 5 minutes late in the evening by being 2 minutes early in the morning.
<egg|work|egg>
!wpn UmbralRaptor
* Qboid
gives UmbralRaptor a Selenian trihexaflexagon
<UmbralRaptor>
egg|work|egg: research is still boring (see last night's comments), but should be getting results soon?
<egg|work|egg>
UmbralRaptor \o/ \o/ \o/
<egg|work|egg>
!pet UmbralRaptor
* Qboid
pets UmbralRaptor
* UmbralRaptor
attempts to purr
<bofh>
dx: I will either be in Zürich or back in Paris on Sunday, but thanks anyhow.
<bofh>
!wpn egg
* Qboid
gives egg a vorpal penguin-like bandersnatch
<bofh>
dx: OHH THAT MIGHT EXPLAIN HOW EVERY BLOODY HOTEL IN THE CITY IS FULL SOMEHOW
<dx>
:D
<dx>
yeah that's why i pasted it
<bofh>
yeah that was surreal. like, it was a Thurs->Fri in *September* (i.e. far from normal tourist season) & moreover, in a city that is not Paris, so yeah that was utterly confusing.
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<bofh>
egg: hopping into the Lumière Brothers museum
<bofh>
it occurs me that this would be a particularly useful time to have, like, a camera but yeah. >_>
<egg|work|egg>
!u
<Qboid>
U+007F ()
<egg|work|egg>
...
<egg|work|egg>
why do you have a random delete in your message
<bofh>
erm, what the hell
* UmbralRaptor
's keyboard generates them sometimes.
<egg|work|egg>
UmbralRaptor: it generates them in bofh's messages?
<bofh>
I have no idea? ¯\_(ツ)_/¯
<egg|work|egg>
tbh since I get bofh's train tickets at this point I wouldn't be that surprised if UmbralRaptor injected characters into bofh's messages,
<bofh>
also ugh my knees are finally starting to calm down again.
<UmbralRaptor>
egg|work|egg: no, but sometimes in mine.
<egg|work|egg>
your knees?
<UmbralRaptor>
s/mine/my messages/
<Qboid>
UmbralRaptor meant to say: egg|work|egg: no, but sometimes in my messages.
<egg|work|egg>
so I mean bofh's knees
<bofh>
(pretty sure I sprained my medial collateral ligament at some point Sunday in my left knee, then aggravated it a bit by deciding to walk entirely too much Monday evening, Tuesday night and just last night. Right knee being a hurty is as a result of walking funny on that leg due to sprained MCL).
<egg|work|egg>
bofh: but how are you going to walk the Суворов track if your ligaments are sprained,
<bofh>
standing for several hours at concert didn't help either but I can go down stairs (the worst thing by far, weirdly, hurt *much* more than going *up* stairs somehow) w/o limping again so
<UmbralRaptor>
Accidentally collecting random body parts seems more ##whitequark than here.
<bofh>
egg|work|egg: like at the rate this has healed I should be fine as long as I don't need to stand for hours or go down an IRL shepard tone or something.
<bofh>
also why the hell is there a Swiss trail named after a Russian general again?!?
<egg|work|egg>
bofh: because that general went there
<egg|work|egg>
bofh: and then his colleague lost a battle near Zurich so he ran away pursued by the french
<egg|work|egg>
bofh: also remember to sleep at some point
<bofh>
egg|work|egg: I mean that is prolly a good idea, but I was just going to wait until the train to Zürich or Paris to do that. :p
<egg|work|egg>
bofh: how do you still not know whether you are going to zurich or paris O_o
<SnoopJeDi>
egg|work|egg, bofh how much do y'all know about BAOs? I was explaining curvature and the implications for cosmology to someone last night, and said "you can't just go out and measure a triangle in the universe because there's no reference," but to my surprise, the Wikipedia article claims BOOMERanG did pretty much that (but AFAICT it was the normal anisotropy BAO stuff?)
<SnoopJeDi>
To focus that to an actual question: is there a geometrical interpretation of BAOs akin to the toy diff. geo. example "you can make triangles with total angle measure ≠ 180°"
<SnoopJeDi>
cosmology word for decomposition into spherical harmonics basically
<SnoopJeDi>
I understand why the BAO power spectrum (P vs ℓ) gives you an angle of attack on Ω, inasmuch as it appears as a parameter alongside other stuff that we can metric in other ways ("how much baryonic matter is there?" "what's a reasonable prior for the matter distribution in the early universe?")
<SnoopJeDi>
was surprised to see that claim on Wikipedia but don't know enough about autocorrelation to tell if it's erudite or overenthusiastic...
<bofh>
egg|work|egg: literally waiting on figuring out if a thing I'm doing with a friend Saturday afternoon that I hastily agreed to is shiftable to next weekend or not (like, especially annoying since I would still have to head back to Paris, but I could still just go Zürich Sun/Mon, but OTOH you're working there, and heading out to Gèneve on like Thurs, being there Thurs/Fri, then heading to Zürich seems
<bofh>
optimal. At the same time that's *another* ...
<bofh>
... timeshift and augh)
<bofh>
also SERIOUSLY BAO is just spherical harmonic decomposition? -.- I knew that seemed famili despite the terms being out of nowhere.
<SnoopJeDi>
the relevant BOOMERanG report is https://arxiv.org/abs/astro-ph/0004404 if you're interested, but no worries really, I just figured it might be something near the top of your very good maths brains
<SnoopJeDi>
pp. 23 demonstrates the way I typically think about it: different "bands" of scale as sensitive probes of (statistical) cosmological parameters
<egg|work|egg>
bofh: and yeah, I work, so Monday is no
<SnoopJeDi>
but IANAC either so my inflation/GR-fu is weak
<SnoopJeDi>
cc UmbralRaptor too, triangles? ^
* egg|work|egg
meows at bofh
* bofh
meows at egg|work|egg
<SnoopJeDi>
!pet egg|work|egg
* Qboid
pets egg|work|egg
<SnoopJeDi>
!pet bofh
* Qboid
pets bofh
* egg|work|egg
pokes bofh in the chat
* bofh
meows
<UmbralRaptor>
SnoopJeDi: yeah, I think it's just working with some assumption about the ~quantum fluctuations~ and spherical harmonics.
<SnoopJeDi>
UmbralRaptor, so would you say it's akin to "measuring triangles" or is that a stretch too far?
<UmbralRaptor>
SnoopJeDi: That's the analogy I've always heard.
<SnoopJeDi>
huh.
<SnoopJeDi>
I guess I'll have to find some lit review material. There are a few promising-looking refs in the BOOMERanG report. Thanks for letting me pick your brain about it :)
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<UmbralRaptor>
I'd be tempted to poke at SDSS BAO and/or Planck papers?
* UmbralRaptor
🔪 radvel in the absolute directories.
<kmath>
<macodiseas> @planet4589 @ToughSf 🤔 Is Principia good enough to replicate the Helios trajectory? @DJSnM ⏎ ⏎ (after I trashed all of… https://t.co/UXTpS1jj8b
<kmath>
<DJSnM> @macodiseas @planet4589 @ToughSf Sure, it’s a proper n-body integrator and even supports oblateness of planets. It… https://t.co/KwyLeg5vci
<iximeow>
"It does miss things like radiation pressure & galactic tides but Helios is fine."
<iximeow>
lol
<bofh>
iximeow: rOFL
<UmbralRaptor>
Okay, but last time I used Principia for ephemeris it ate all my ram and swap.
<iximeow>
!feed Qboid
* UmbralRaptor
ignores that this was on a system with like 1 gig of ram and 3 of storage.
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<egg|work|egg>
bofh: iximeow: umbralraptor: we are working on gravity models more refined than oblateness fwiw
<egg|work|egg>
okay I don't intend to go to degree and order 180,
<egg|work|egg>
!pet whitequark
* Qboid
pets whitequark
<APlayer>
!pet egg
* Qboid
pets egg
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<bofh>
egg|work|egg: how important is n > 2 for gravity models?
<egg|work|egg>
depends on the body
<egg|work|egg>
the moon is famously misshapen
<egg|work|egg>
Mars is weird too
* egg|work|egg
pokes Olympus with a stick
<bofh>
I mean, for planets (particularly gas/ice giants). Moons are small enough and misshapen enough that yeah I can easily see it mattering.
<egg|work|egg>
bofh: well, the Moon is big, and I don't think anybody is trying to turn Mars into a smol planet
<SnoopJeDi>
UmbralRaptor, yea I poked at the Planck DR2 paper too, but I think Planck's strongest result comes from the more "algebraic" global method of tallying up different forms of mass-energy?
<bofh>
uhm, ~3475km average radius is considered "big"?
<SnoopJeDi>
i.e. Ωk = Ωbaryons + Ωphotons + ΩDE
<iximeow>
bofh: when compared with the average size of an object in the solar system,
<SnoopJeDi>
where baryons are the things wot glow, CMB is pretty free if your TV has good reception, and *mumble mumble* dark energy
<SnoopJeDi>
I mean they *do* use BAO too so maybe it's both idk
<SnoopJeDi>
Mostly idle wondering about that one class I took once upon an undergrad :)
<SnoopJeDi>
from a colloquium many moons ago, but dots came in up in another channel and that's one of my favorite QC-implementation papers
<UmbralRaptor>
Ylm is a treacherous orb.
<bofh>
so I first read 'Ylm' as spherical harmonics, then as like, I'unno, assistant apprentice to Yog-Sothoth or something? Still not sure which is more correct,
<SnoopJeDi>
oh yes, I did send you at least the hairpin, I recall.
<bofh>
I like how one of the first things I intend to do once back in Paris is make sure to finally get some damn photos of the Hammurabi pillar somehow.
<kmath>
<eggleroy> "cancellation isnt real," i assure myself as i close my Белоусов and ram the degree 90 legendre polynomial with my… https://t.co/C3j5b9FBlB
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<SnoopJeDi>
LOL
<bofh>
egg: HALP I CAN'T STOP LAUGHING
<egg>
!meow bofh
* Qboid
meows at bofh
<egg>
!wpn
* Qboid
gives egg a котяchrome camel
* egg
pokes bofh with a котяchrome camels
<egg>
s/.$//
<Qboid>
egg meant to say: /me pokes bofh with a котяchrome camel
<egg>
whitequark: camels are sort of котяchrome, right?
<bofh>
egg: I got *so* many weird looks at Fourvière just right now.
<bofh>
turns out it echoes really well around here
<egg>
what have you done
<bofh>
egg: just laughed really really loudly and almost fell off the wall I was sort of precariously sitting on.
<egg>
also /me meows at chat
<egg>
<bofh> egg: just laughed really really loudly and almost fell off the wall I was sort of precariously sitting on. << bofh go to sleep,
<bofh>
egg: uhh don't blame me for you making the best dril-like post I've seen in awhile,
<bofh>
also like, there is more stable seating here but the view isn't as good.
<egg>
ah, that :-p
* egg
pokes bofh in the chat
<bofh>
egg: sec
<bofh>
relocated to an actual bench, instead of a very thin wall w/a 4.5-metre straight-down drop.
<egg>
aaaaaaaaaaaaaaa
<bofh>
look it had a good view and eduroam at -61dBm,
<egg>
!wpn bofh
* Qboid
gives bofh a 𓌪
<egg>
!wpn rqou
* Qboid
gives rqou a zero-width lenticular gasket/épée hybrid
* egg
stares at the moon's gravity field
<egg>
aaaaaaaaaaaaaaaaaa
* egg
blames sigfig
<UmbralRaptor>
The masscons are not caused by her crashing rockets.
<egg>
UmbralRaptor: how do you know,
<UmbralRaptor>
egg: They'd be clearly flower shaped?