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.
<egg> UmbralRaptor: does ANBO count,
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<UmbralRaptor> egg: ANBO works like https://photos.app.goo.gl/b56KTsSssqSWM1pg2 so not really? =S
<egg> UmbralRaptor: on a more serious note, crows?
<Iskierka> ... so it was a few days ago but I'm very confused at the guy telling Ellied that SRAM loses data immediately on losing power. SRAM holds data CONSIDERABLY longer than DRAM
<egg> UmbralRaptor: in my first semester at ETHZ I took an astronomy course taught by Schmid and Schmutz
<UmbralRaptor> egg: maybe. Somewhat difficult to go back to galaxies. >_>;;
<Ellied> Iskierka: I found that on wikipedia immediately after I saw that tweet. I'm still a little confused by a lot of this.
<egg> UmbralRaptor: I mean, there are other diapsids here
<egg> UmbralRaptor: Schmid works on polarimetry of planets, and is involved in SPHERE and EPICS
<Ellied> I'm gonna hold onto my "electrically-resettable RAM should be a buyable class of part" stance for a little longer.
<Iskierka> Yeah. I don't recall exact design details that could explain why it persists to much, but my dad worked with SRAM systems some while ago, and via assuming what values would be initialised to (zero) he found that there would be very large amounts of data remaining after more than a minute of no power
<UmbralRaptor> Hm.
<Iskierka> meanwhile DRAM is refreshing like 15 times per second to ensure integrity
<Ellied> EPICS, aaaaaa
<UmbralRaptor> EPICS?
<Qboid> UmbralRaptor: [EPICS] => Experimental Physics and Industrial Control System
<UmbralRaptor> Uh
<egg> Schmutz doesn't seem to be doing planety stuff http://www.pmodwrc.ch/staff/wschmutz/official/index.php
<egg> crap, acronym collision
<egg> SPHERE?
<egg> !acr -add:SPHERE Spectro-Polarimetric High-contrast Exoplanet REsearch instrument
<Qboid> egg: I added the explanation for this acronym.
<Ellied> oh, not that EPICS?
<egg> Ellied: no it's Exoplanet Imaging Camera and Spectrograph
<Ellied> oh.
<egg> on ELT
<Ellied> Qboid needs a multiple-explanations-for-one-acronym feature
<egg> basically like SPHERE but s/Very/Extremely/
<egg> Ellied: we just need to define a convention for the multiple expansion
<egg> comma-separated?
<egg> Ellied: I mean unless you want Qboid to be smart about it and try to guess which one is relevant but that seems hard and obnoxious if wrong
<Ellied> yeah
<egg> UmbralRaptor: oh Schmid is actually on the author list here https://www.eso.org/sci/libraries/SPIE2010/7735-84.pdf
<Ellied> we could have named categories, like "astronomy" "aerospace" "math" etc, so if there are multiple you can say "astronomy EPICS?" and get that, or "physics EPICS?" and get the one that's there now.
<egg> wait why is he in the physics dept and not the astronomy one Ꙩ_ꙩ
<Ellied> if the acronym exists but doesn't have any explanations for that category, it'll say what categories do exist.
<egg> Ellied: and then you notice the guy is in a physics department doing astronomy :D
<Ellied> yay!
<egg> ah wait no they're all in there
<egg> is there no separate astronomy thingy then?
<egg> UmbralRaptor: so see there's the crow group http://www.ipa.phys.ethz.ch/people/schawinski-group.html
* Ellied is probably destined for astronomy-related detector work. That's where I'm planning to start looking for grad schools.
<egg> UmbralRaptor: and schmid has another one http://www.ipa.phys.ethz.ch/people/schmid-group.html
<UmbralRaptor> Physics and astro overlap, so…
<Ellied> yeah, quite a bit
<Ellied> my friends today were surprised when I told them that some unis actually have an astronomy department instead of just having that folded into physics
<egg> very german english page: "Mr Prof. Dr. Günther Dissertori"
<egg> (he taught my first semester physics course)
<UmbralRaptor> Ellied: my advisor does lots with detectors, so I could ask him for suggestions?
<egg> yeah so astrophysics share an institute with particle physics within d-phys apparently
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<egg|zzz|egg> !wpn UmbralRaptor
* Qboid gives UmbralRaptor a PowerPoint birb
<bofh> !wpn egg|zzz|egg
* Qboid gives egg|zzz|egg a Schwarz photodiode
<egg|zzz|egg> !wpn bofh
* Qboid gives bofh an ultramatic ?
<egg|zzz|egg> !wpn Ellied
* Qboid gives Ellied an upsilon gun
<egg|zzz|egg> Ellied: also icymi <egg|zzz|egg> does Ellied design mount controllers, http://gemini-2.com/front_panel_pinouts_mini-gemini-2.php
* UmbralRaptor rewrites the birb in beamer.
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<kmath> <hikari_no_yume> @sigfig @whitequark clearly it's IPA intended to be pronounced /twinəʌɪ̥ɹp/
<UmbralRaptor> !wpn e_14159
* Qboid gives e_14159 a code-switching knife
<Ellied> egg|zzz|egg: future Ellied absolutely does. That looks like exactly my sort of thing.
<Ellied> ee, someone in canada saw my tweets and hinted that there might be an opening up my alley where he is
<Ellied> it's an absurdly long and dubious shot, but what the hell, I'll try pursuing it
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* egg gives Ellied a DIN 45322 to USB-A cable
<egg> ... we need to have a greeningbot that generates cables from Ellied's bag
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<egg> !wpn UmbralRaptor
* Qboid gives UmbralRaptor an irrelevant charm octagon
<egg> !wpn Ellied
* Qboid gives Ellied a redundant ½λ gun-like vertex
<egg> !wpn bofh
* Qboid gives bofh a triangulated Schwarz minion
<egg> !wpn whitequark
* Qboid gives whitequark an octahedron
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<APlayer> Hi there!
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<kmath> <stephentyrone> @myrrlyn Small dogs are a fiction. Those are some kind of rodent or lagomorph.
<egg|laptop|egg> (otters otoh are real)
<e_14159> egg|laptop|egg: You mean rats?
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<BPlayer> Okay, so I just found this random function while trying to get a rather specific curve... And what the heck is this? f(x) = x^(1/x)
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<BPlayer> Seems like it has a global maximum at x = e?
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<APlayer> Does this kind of function even have a name?
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<Iskierka> this is a fun graph
<Iskierka> also twitter is being dumb. I've been unfollowed from at least two accounts and haven't been using an interface where unfollow is an easy misclick
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<Iskierka> also hexchat is still dumb
<egg> yeah
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<egg> !wpn hattivat
* Qboid gives hattivat a spectrophotometer/hydrochlorofluorocarbon hybrid
<hattivat> o/ egg
<hattivat> !wpn egg
* Qboid gives egg a progressive ghost
<bofh> I love NTRS
<egg> bofh: so principia uses this status enumeration for its errors https://cloud.google.com/speech/reference/rpc/google.rpc
<egg> bofh: phl is writing collision detection in the force computation of the ephemeris
<egg> bofh: guess which status this is
<bofh> OUT_OF_RANGE?
<egg> bofh: yup :D
<Qboid> [#1640] title: Detect collisions in the force computation and thread errors through the integrators and the ephemeris | This is a step towards solving #1628. | https://github.com/mockingbirdnest/Principia/issues/1640
<Qboid> 5d 0h 0m 0s left to event #17: et al./Falcon 9 v1.2 [at 2017-12-08 18:20:00]. Say '!kountdown 17' for details
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<egg> !wpn bofh
* Qboid gives bofh an extensive stellarator/conflict hybrid
<kmath> <lindsey> @palvaro @bridgetkromhout I should do one of those "latency numbers you should know!" things, except instead of "L1… https://t.co/nQc4xKL0eG
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<soundnfury> egg: L1 latency is 2 * (1.5Gm / c) = 10.006 seconds RTT.
<UmbralRaptor> Uh
<soundnfury> I, uh, might be talking about a different L1 ;)
<soundnfury> (also I gave an unjustified number of sig figs, but hey)
<kmath> <TetZoo> Breaking maniraptoran news: the Haarlem Archaeopteryx is not an Archaeopteryx, but a new taxon of anchiornithid nam… https://t.co/GqDJSYb52g
<UmbralRaptor> Iskierka: exploiting this is a key feature of VLBI (Very Long Barkline Interferometry)
<kmath> <goodfellow_ian> One of my favorite samples from the Progressive GANs paper is this one from the "cat" category. Apparently some of… https://t.co/fRSS0F7Jsg
<egg> argh, whenever I see talk of significant figures I wonder whether it's about @sigfig
<egg> (tbh it's probably best to say sig. dec. or sig. bits anyway)
<kmath> <stephentyrone> @csferrie @aemylt Hot take: Anyone who uses `+` for inclusive OR or string concatenation is a monster.
<UmbralRaptor> Not sure I agree, but using + for XOR or NAND *is* monsterous.
<soundnfury> UmbralRaptor: nah, + for XOR is exactly right in F₂. Also, × or · for AND.
<APlayer> I'd use * for AND and + for inclusive OR or string concatenation?
* UmbralRaptor generally agrees with APlayer here
<egg> UmbralRaptor: wat? + *is* XOR
<APlayer> This may be the first time someone just agreed with me on this channel :P
<APlayer> egg: Uh, what about inclusive OR?
* egg slaps UmbralRaptor with an ichtyosaur
<APlayer> Also, is there some curve that starts steeply at 0 and gets flatter as x increases? I am looking at roots and logarithms here, but neither curve fit my need, and I have so far not managed to modify them properly. Any alternatives?
<APlayer> In particular, I need something flatter than square roots for big x, but steeper than logarithms for small x
<APlayer> And it would be nice if I did not have to use log(x + 1) to prevent it from getting negative for positive x, but that's doable
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<UmbralRaptor> ow
<hattivat> APlayer: you mean someting like 2*ln(x)?
<APlayer> I tried using a factor k for k * ln(x), but couldn't find a good value, as the flat part would grow too large before I was satisfied with the steep part
<hattivat> you seem to have really narrow constraints
<APlayer> I do. Landing a booster in KSP Falcon 9 style, and trying to pinpoint the landing using lift guidance. I currently try to apply a single all-around formula for the whole descent, but the conditions vary wildly between free-fall/high distance to the landing site, max Q/medium distance up to terminal velocity/low distance
<APlayer> The curve I need it the amount of correction I need to apply given the impact error distance, which should output around 30 for values of 2000 and more (using a Min() function here), and around 5 for values smaller then 300. Around 500 it should go rather steeply up towards 20 - 30.
<APlayer> I currently use 3 * sqrt(x), but that causes wild oscillations for smaller inputs, as it grows really quickly
<soundnfury> APlayer: maybe try fitting a ratio of polynomials? even something as simple as y=\frac{x+a}{x+b} is surprisingly versatile
<APlayer> Woah, that looks nice!
<APlayer> Okay, this is plain and simple amazing! Thanks a lot, soundnfury!
<APlayer> I think I found a curve that suits my needs!
<APlayer> Doesn't even need the Min() stuff now! :D
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<APlayer> Okay, I've got to go now. See you tomorrow! Thanks again for that formula!
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<egg> !wpn UmbralRaptor
* Qboid gives UmbralRaptor an infinite Maclaurin cathedral
<egg> !wpn -add:adj Laurent
<Qboid> egg: Adjective added!
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<egg> !wpn bofh
* Qboid gives bofh a multipole bolt with a snek attachment
* UmbralRaptor ? things, and tries to set up the integrals for a cone.
* egg pokes UmbralRaptor with kozai
<soundnfury> !wpn egg
* Qboid gives egg a Ляпунов Van Allen wrench
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<egg|phone|egg> Moo
<soundnfury> OoM
<egg|phone|egg> UmbralRaptor: Why a cone
* UmbralRaptor hands soundnfury a mana potion.
<UmbralRaptor> egg|phone|egg: Homework problem involves the moments of inertia of a cone.
<egg|phone|egg> The only thing there is to life is triangles?
<UmbralRaptor> The triangles aren't so bad. The circles, though.
<egg|phone|egg> Ah yes they're poor triangles
<UmbralRaptor> Stabbing someone with a circle is hard.
<soundnfury> UmbralRaptor: ?
<UmbralRaptor> soundnfury: random memory from when I played MMOs: OoM == Out of Mana
<soundnfury> I see.
<soundnfury> Out of Memory.
<soundnfury> as in the fabled "oom-killer"
<UmbralRaptor> Why you sometimes open a web page and your music player and IRC client die.
* UmbralRaptor ?
<soundnfury> well, that's more because browsers are fsckin' hogs…
<Qboid> [#1639] title: Spacecraft orientation change during parent body transition | Hi,... | https://github.com/mockingbirdnest/Principia/issues/1639
<egg|phone|egg> Tilting the universe but forgetting bits thereof
<egg> UmbralRaptor: grump you have nerd-sniped me into thinking about moments of inertias of cones
* UmbralRaptor spins egg like a dreidel.
<egg> UmbralRaptor: along the axis is easily integrated though right? and perpendicular to it you can make it a sum of cylinders hopefully
<UmbralRaptor> egg: I need a 3x3 matrix
<egg> UmbralRaptor: well you just need three numbers https://en.wikipedia.org/wiki/Moment_of_inertia#Principal_axes
<egg> UmbralRaptor: your cone is finite and homogeneous?
<egg> or is it actually an infinite ice cream or something
<UmbralRaptor> Cone is finite and homogeneous
<UmbralRaptor> The tungsten website isn't helping.
<soundnfury> egg: is the ice cream made from homogeneous milk?
<soundnfury> UmbralRaptor: you mean tungsten helium-nucleus?
<egg> UmbralRaptor: so then the moment of inertia along the axis of rotation is just the sum over the cone of the ρ r² r dφ dr dh, right?
<UmbralRaptor> soundnfury: no, just the references/descriptions
<soundnfury> aight.
<UmbralRaptor> egg: maybe. Confusingly it looks like rectangular coordinates are required?
<egg> wat why
<egg> why would you do that to yourself
<soundnfury> you can do the integration in any co-ordinate system you like
<soundnfury> it's only the kernel (x² in this case) that has to be in cartesians
<soundnfury> well, ρx² I guess
<egg> wait why would you do anything cartesian here
<UmbralRaptor> We were given I_ij = \int_v (\delta_ij r^2 - x_i x_j) \rho dv for finding the moments of inertia.
<egg> UmbralRaptor: you know about principal axes though right?
<UmbralRaptor> Yeah, but we get those in the second part of the problem.
<egg> ... why are they doing that backward
<UmbralRaptor> ^problem
<egg> UmbralRaptor: well then shrug, x1 = r cos φ, x2 = r sin φ, dV = r dφ dr dx3, sum for x3 ranging from 0 to h, for r ranging from 0 to R x3/h, for θ ranging from 0 to 2π of what you said
<egg> um φ=θ because I can't decide what to call the angle
<egg> ϡ
<UmbralRaptor> hm
<egg> (like I would have started by saying the principal axes are obvious, find the centre of mass, compute the principal moments, and then do the stuff about the apex by parallel axis, but shrug)
<egg> I guess if you like integrating more than geometrying that works :-p
<UmbralRaptor> I got inconsistent results with geometrying the triangle. =\
<egg> UmbralRaptor: uh of course your formula has an r but that's not the same as my r
<UmbralRaptor> Yeah
<egg> UmbralRaptor: your r is r^2+x3^2 (quite obviously, also immediate calculation with the sum of the squared sting of death and costing of death being 1)