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.
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* egg stares at Raptop
<egg> is Raptop UmbralRaptop
<egg> or UmbralRaptor
<egg> tbh there are three eggs too so,
<awang> UmbralRaptorp
* Raptop explodes in a shower of 2.4 GHz packets.
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<iximeow> !wpn UmbralRaptop
* Qboid gives UmbralRaptop a transverse induction-like periwinkle
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<UmbralRaptop> !wpn iximeow
* Qboid gives iximeow a statistical brachistochrone
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<kmath> <stevecheckoway> Cats make great pillows for cats. https://t.co/CrvG9O24Qr
<egg> !wpn whitequark and котя
* Qboid gives whitequark and котя a flipped glider
<UmbralRaptop> "cuddle puddle" ^_^
<egg> whitequark: btw, what is the name of the dumb cat these days? I'm confused between эта хуйня, порошок, and кот
<UmbralRaptop> !wpn egg
* Qboid gives egg an alternating projection
* UmbralRaptop sets a 2-level system on fire.
<kmath> <CryptoCypher> I have a cat OSI model photo saved for some reason??? https://t.co/981rLbah3I
<kmath> <nokusu> @stevecheckoway @climagic :!killall -9 vim
<UmbralRaptop> uh
<bofh> ROFL
* egg stabs MSVC in the template pack-related bugs
<bofh> ROFL I JUST DISCOVERED THE COPY OF THE ISO14496-3 SPEC I PUT UP ON RANDOM WEBSPACE OF MINE IS THE FIRST GOOGLE RESULT & BEATS ISO/IEC
<egg> bofh: sadly the protocol is not ftp so this isn't quite peak kspacademia
<awang> bofh: read.pudn.com?
<bofh> awang: no, the second in that case
<awang> iso is second for me
<bofh> first for "iso14496-3", second for "iso 14496-3", in an incognito tab
<bofh> ¯\_(ツ)_/¯
<bofh> I take solace in the fact that it is the most recent spec ver, the one on pudn is the 2001 ver :P
<awang> First for me for "iso14496-3", fourth for "iso 14496-3"
<awang> idk
<awang> Sorry for the buzzkill :(
<bofh> clearly I should've added the space, but it seems silly to
<awang> Add a version with the space that redirects to the one without?
<awang> Then you can be top result for both!
<bofh> Good call tbh.
<whitequark> egg: порошок
<whitequark> UmbralRaptop: yes.
* UmbralRaptop assumes that this is related to the hug comment.
<UmbralRaptop> !wa 198 CHF in USD
<Qboid> UmbralRaptop: convert CHF198 (Swiss francs) to US dollars: $208.12 (US dollars)
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<soundnfury> UmbralRaptop: 50% sounds way too low tbh
<soundnfury> surely you could tighten that bound a bit
<egg|phone|egg> !Wpn whitequark
* Qboid gives whitequark a centripetal helicoid
<kmath> <stephentyrone> I am told that in Fields That Are Not Mathematics, dunking on the distinguished invited speaker is poor form, rather than How We Show Love.
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<egg> bofh: naming question: is there a good name for "element of the phase space"
<egg> (I already have something called system state :-p)
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<UmbralRaptop> egg: quosition and pomentum?
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<soundnfury> egg: state vector?
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<UmbralRaptop> soundnfury: large errors exist due to all the lurkers.
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* egg has found a release blocker for the Coxeter release
<soundnfury> UmbralRaptop: why else would they be lurking?
<egg> obviously that means we need to slow down the moon's orbit if we can't resolve it by the new moon
<egg> UmbralRaptop: any advice on slowing down the moon
<soundnfury> egg: ok, I'll get the comets, you work out the trajectories for their close lunar flybys
<soundnfury> OH WAIT you can't because Principia is broken :P
<egg> nah only in-game
<UmbralRaptop> egg: accelerate it forwards?
<egg> UmbralRaptop: well yes
<egg> but how
<UmbralRaptop> Do you still have that black hole you were waving around during compiles?
<egg> can't find it
<egg> it must have evaporated
<bofh> goddamn hawking radiation :P
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<egg> !wpn bofh
* Qboid gives bofh a simulated tardigrade
<egg> whitequark: how are котя's kittens doing?
<whitequark> they grow
<whitequark> but i'm in hk as of today
<egg> ow, so no котяpics котяkittenpics? :'(
<egg> bofh: is there a name for an ODE which has a splitting
<bofh> a... splitting?
<whitequark> egg: you could ask printer
<egg> bofh: y′ = f(y, t) + g(y, t) (with y′ = f(y, t) and y′ = g(y, t) being integrable)
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<bofh> egg: linear inhomogeneous?
<bofh> egg: I mean that's a first-order ODE so solving it is trivial no matter what.
<egg> ?
* egg is confused
<bofh> like, the name is "linear inhomogeneous"?
<bofh> unless I'm mistaken
<egg> uh
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<egg> bofh: what is linear here
<egg> bofh: f and g need not be linear (an example would be the Wisdom-Holman Keplerian + perturbation splitting)
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<egg> or just the usual kinetic + potential splitting
<bofh> ah. okay, so just general inhomogeneous?
<egg> bofh: I mean, it's just an arbitrary ODE, except that you can express its RHS as a sum of things that you can exactly flow for some reason
<bofh> (also isn't the perturbation component of the WH splitting linear, with only the Keplerian part being nonlinear?)
<egg> the perturbation component is gravitational forces
<egg> those tend to be somewhat nonlinear?
<egg> the T part of the T+V splitting is linear though
<egg> hm
* egg may be confused
<egg> ;
<bofh> no, I think I am, you're right.
<egg> bofh: I mean the solution of X'={X,V} is linear though
<egg> (or affine rather, time lives in an affine space not a vector space)
<bofh> Yeah.
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<egg> bofh: random tidbit from the Ada reference manual: in Ada 83, "has no other effect" was a technical term
<egg> bofh: so sometimes you have a paragraph like "The elaboration of a discriminant part has no other effect."
<bofh> LOL
<egg> bofh: so you have 12.o that comments on that in 95 :-p http://www.adaic.org/resources/add_content/standards/95aarm/AARM_HTML/AA-3-1.html
<egg> "RM83 uses the term ``has no other effect'' to describe an elaboration that doesn't do anything except change the state from not-yet-elaborated to elaborated. This was a confusing wording, because the answer to ``other than what?'' was to be found many pages away. In Ada 95, we change this wording to ``has no effect'' (for things that truly do nothing at run time), and ``has no effect other than to establish that so-and-so
<egg> can happen without failing the Elaboration_Check'' (for things where it matters)."
<egg> bofh: I mean, at least it was defined, and even in 83 it tried to avoid having meaningless words even if the wording was odd (glares at the python reference)
<egg> bofh: AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA #1752 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
<Qboid> [#1752] title: Capture by reference to fix an addressing fault | It's not a bug in the compiler unless it's a bug in the compiler. | https://github.com/mockingbirdnest/principia/issues/1752
<egg> bofh: alignment fhtagn
<egg> bofh: well at least we don't need to slow down the moon anymore
<egg> !wpn whitequark
* Qboid gives whitequark a contravariant edgy quokka
<egg> !wpn bofh
* Qboid gives bofh a minimum screaming denormal
<egg> um
<egg> bofh: does 2^-1074 scream
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<kmath> <41Strange> Gigantic Felt Cat Head created by Housetu Sato, a teacher at the Japan School of Wool Art ⏎ #HappyCaturday https://t.co/B8D0KMTKbP
<kmath> <bofh453> @whitequark So I once did x86_64 -> SIMH (VaxStation) -> UNIVAC 1108 emulator -> UNIVAC 494 emulator, not sure if that counts. :P
<egg> OꙨ_ꙩo
<egg> bofh: the name special second order differential equation appears to be a thing for q″ = f(q, t), is there a name for q″ = f(q, q′, t)?
<egg> explicit second order apparently
<bofh> ah
<egg> !u ⅍
<Qboid> U+214D AKTIESELSKAB (⅍)
<egg> wow
<kmath> <Random_Guy_32> @monokromfonts ⅍?
<egg> !u ℁
<Qboid> U+2101 ADDRESSED TO THE SUBJECT (℁)
<bofh> Isn't U+214D just an A/s ligature?
<egg> compatibility decomposes to A/S I think
<egg> and 2101 to a/s
<egg> bofh: http://graphemica.com/%E2%84%96 so you need letterlike symbols to interpret Baudot in the UCS :D
<bofh> egg: also I just scrolled up & saw #1752 & oh gods
<Qboid> [#1752] title: Capture by reference to fix an addressing fault | It's not a bug in the compiler unless it's a bug in the compiler. | https://github.com/mockingbirdnest/principia/issues/1752
<bofh> alignment fhtagn indeed.
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<bofh> (I do the lazy thing personally & use movups a lot, since the perf penalty often isn't *that* bad)
<egg> bofh: what do you mean
* egg doesn't understand what the lazy thing is
* soundnfury has no idea what that syntax even means, but it reinforces my belief that C++ is Just Weird™.
<egg> https://twitter.com/whitequark/status/972912048181993473 we must bring oxygen levels back to carboniferous levels to get our giant odonates back
<kmath> <whitequark> apparently if you grow dragonflies in high-oxygen environments they grow noticeably larger (15% larger in 31% O₂) https://t.co/NcDfoTHEVc
<soundnfury> egg: yeah but if you did that wouldn't you also get terrorised by giant bees?
<egg> meh a meganeuropsis will eat that
<bofh> ^
<egg> bofh: look at the fun character set on fig. 1 http://www.samhallas.co.uk/repository/telegraph/b6_baudot_multiplex.pdf
<UmbralRaptop> We'll get giant spiders also, right?
<soundnfury> aaaaaaaaa
<soundnfury> hmm, what's oxygen toxicity at those levels like? would I be already dead by the time the megafauna came knocking?
<egg> bofh: ABCDEÉFGHIJKLMNOPQRSTUVWXZᵗ 18902&ᶠ7ʰᵒ6(=)№5%/-;!4`?,3:. is a sane character set,
* soundnfury sends egg a letter to shift his figure
* UmbralRaptop stares at the numbers.
<egg> bofh: also the character set has two different spaces!
<UmbralRaptop> I want to say that oxygen toxicity requires a partial pressure at least a few times that of present?
<Fiora> to be fair, oxygen is always toxic, even at atmospheric pressures.
<Fiora> it just takes about 80 years to kill you.
* UmbralRaptop glares at mitochondrial production of free radicals.
<whitequark> Fiora: do we observe that people living in rarefied atmosphere live longer?
<egg> bofh: who is screaming "stop defining differential equations" at me. show yourself. i will never stop https://github.com/eggrobin/Principia/blob/first-order-ode/integrators/ordinary_differential_equations.hpp#L41-L216
<Fiora> whitequark: ..... good question
<Fiora> There's been meta-studies.
<Fiora> note higher altitudes also means more radiation.
<Fiora> i believe they've concluded that, at the very least, heart disease and heart attack are extremely uncommon at high altitudes.
<Fiora> "Voors et al. confirmed the negative relationship between altitude and mortality in the highest 99 out of 100 largest cities of the United States up to an altitude of 1650 m"
<whitequark> Fiora: isn't that just because people get free exercise in mountains
<egg> Fiora: argh so you are saying there's a downside to having giant odonates
<Fiora> nope, this applies to US cities that happen to be at altitude, too.
<Fiora> "The moderate hypoxia stimulus at altitudes up to 2500 m has been suggested as a potential contributor to the beneficial effects on cardiovascular health [7, 21]. From a biological perspective it has been hypothesized that hypoxia inducible factor (HIF) pathways might mediate the reduction of cardiovascular mortality at altitude [13]. HIF-1 is a key regulator of processes such as erythropoiesis, angiogenesis, apoptosis and metabo
<Fiora> they do talk about exercise being also a factor
<Fiora> "In addition, exercising at altitude may represent a superimposed intermittent hypoxia-like stimulus causing beneficial pre-conditioning effects [26]. It is thought that adaptation to such intermittent hypoxia stimuli which are largely related to nitric oxide production may provide protection against subsequent more severe and prolonged hypoxia as well as protection against other stresses "
<whitequark> huh.
<tawny> huh. Guess I'm moving to denver now
<egg> !wpn -add:adj oxygenated
<Qboid> egg: Adjective added!
<egg> !wpn -add:adj oxidized
<Qboid> egg: Adjective already added!
<egg> !wpn Fiora
* Qboid gives Fiora an atomic trait
<egg> !wpn whitequark
* Qboid gives whitequark an oscillating hydra
<soundnfury> !wpn tawny
* Qboid gives tawny an egotistical hybrid
<soundnfury> !wpn egg
* Qboid gives egg an ignited honey-roasted flail
<soundnfury> "Ingredients: Dried flail sweepings, artificial honey-roasting agent, salt."
<BPlayer> eggotistical hybrid?
<egg> Fiora: bofh: I'm wondering whether that makes sense https://twitter.com/sl2c/status/972743803671953409
<kmath> <sl2c> @FioraAeterna @longestaugust If you count the needle as a gimbal 😜
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<UmbralRaptop> So I found this on my front door. https://photos.app.goo.gl/yFHsFzsRpqQbIuZU2
<BPlayer> Speaking of gimbal (locks), I still don't quite get how Quaternions work...
<egg> Fiora: i.e. what happens if the outer articulation is coaxial with the axis of the needle
<bofh> egg: ROFL
<egg> bofh: is that about the integrators or about the character set
<bofh> egg: the integrators
<bofh> (we need a @frobenius_dril)
<egg> (via mnxmnkmnd on mastodon via floral diagrams)
<egg> bofh: something something Coxeter notation
* soundnfury gives egg a sleeping symbol
<egg> !wpn -add:adj Fuchsian
<Qboid> egg: Adjective added!
<soundnfury> egg: is that defined as "of or pertaining to Klaus Fuchs"? :P
<egg> Fiora: I feel like if the outer axis is orthogonal to the plane of the compass things might get awkward?
<egg> Fiora: or, to more directly answer your question, you have gimbal locking with three gimbals because the 3-torus does not cover SO(3), but you should get it with two because the 2-torus does not cover the 2-sphere?
<egg> cc bofh to check if I'm not spouting complete insanity
<egg> whitequark: every time I see the llvm dragon I am reminded of https://twitter.com/parport0/status/919551182359683073
<kmath> <parport0> @whitequark https://t.co/OGsmov6ToC
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<egg> Fiora: ah yes it's even in the Wikipedia article https://en.wikipedia.org/wiki/Gimbal_lock#In_two_dimensions
<bofh> egg: yeah that's correct
<egg> I should probably reply to tweets on twitter rather than IRC
* egg bad at the internets
<UmbralRaptop> Eh, IRC works well for sub sub tweeting.
<egg> UmbralRaptop: but I actually want to answer Fiora's question here not sub^k tweet her :-p
<egg> descending chain condition but for subtweets
<egg> and of course I notice a typo (s/in/with/) right after pressing the button... https://twitter.com/eggleroy/status/972959882822537216
<kmath> <eggleroy> @FioraAeterna @sl2c [I should probably reply here rather than on IRC…] ⏎ Yes: https://t.co/gSKbqlfGCE; I think if the… https://t.co/f5HJFXYm9Z
<bofh> rofl
<bofh> egg: if there's a descending chain condition then what do you get by applying Zorn's Lemma to the tweetspace?
<egg> Zorn.
<kmath> <whitequark> here I fixed it https://t.co/KZdemtJbpv
<bofh> rofl
<egg> bofh: of course, you don't get gimbal locking with one axle because the 1-torus covers the 1-sphere :-p
<bofh> well yes, but that strikes me as obvious :p
<egg> bofh: yes but that's an extremely silly way of phrasing it :-p
<bofh> egg: so my response of "that strikes me as obvious" was in relation to "the 1-torus covers the 1-sphere" :p
<UmbralRaptop> 2-axel gimbal lock is the same thing as "Dobson's Hole", right?
<egg> I mean the fact that a single articulation doesn't gimbal lock is also silly obvious without involving tori and spheres simple orthogonal groups
<egg> bofh: now, what happens if you have 6 gimbals and you try to hold your compass in a fixed orientation in 4d
<egg> ~extremely practical question~
<UmbralRaptop> uh
<UmbralRaptop> Is this for whitequark navigating around a proton?
<bofh> egg: is there even a covering map from T^6 to SO(4)?
<bofh> ...
<bofh> this at the same time as I get to the second page in this music theory paper I'm reading and wind up staring at the n-Torus: http://www.brainmusic.org/EducationalActivitiesFolder/Tymoczko_chords2006.pdf
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<egg> UmbralRaptop: yeah, a dobsonian maps the 2-torus to the sphere (or rather half of the 2-torus to the hemisphere, because I don't think you can point it underground)
<egg> or maybe a quarter of the 2-torus?
<UmbralRaptop> The tube tends to not be happy if you try to clip it through the ground.