raptop 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. | We can haz pdf
* Raptop sees a job posting, and wonders if I'll be qualified after graduating
* Raptop checks xp requirements https://jobs.nmsu.edu/postings/34609
<Raptop> whelp
<_whitenotifier-3d18> [Principia] eggrobin reviewed pull request #2125 commit - https://git.io/fjt3d
<egg> Raptop: required generally comes with a lot of quotation marks though
<Raptop> egg: the quotation marks seem to be around the degree part, though. (yeah, we want MSc + 5 years, but BSc + 7 also works)
<egg> mofh: about that underlying one-step method
<_whitenotifier-3d18> [Principia] eggrobin reviewed pull request #2125 commit - https://git.io/fjt3j
<_whitenotifier-3d18> [Principia] eggrobin reviewed pull request #2125 commit - https://git.io/fjtse
<_whitenotifier-3d18> [Principia] eggrobin reviewed pull request #2125 commit - https://git.io/fjtsf
<_whitenotifier-3d18> [Principia] eggrobin reviewed pull request #2125 commit - https://git.io/fjtsJ
<mofh> egg: yes yes, I think I'm starting to actually understand enough of this now
<_whitenotifier-3d18> [Principia] eggrobin reviewed pull request #2125 commit - https://git.io/fjtsm
<mofh> egg: LOL
<_whitenotifier-3d18> [Principia] eggrobin reviewed pull request #2125 commit - https://git.io/fjtsY
<_whitenotifier-3d18> [Principia] eggrobin reviewed pull request #2125 commit - https://git.io/fjts3
* Raptop stares at a CARMENES paper from 2017
<_whitenotifier-3d18> [Principia] eggrobin synchronize pull request #2125: Computed velocities and GRGS dialect - https://git.io/fjtqM
* Raptop wonders if this largely obsoletes my current work
<Raptop> hah
<_whitenotifier-3d18> [Principia] eggrobin synchronize pull request #2125: Computed velocities and GRGS dialect - https://git.io/fjtqM
<egg> whitequark: how is котенька
<egg> !u !
<galois> !: U+0021 EXCLAMATION MARK
<Raptop> A "the two genders" joke, but for whitequark's cats
<Raptop> Okay, CARMENES uses probably >1 order of magnitude more compute than we do for their scheduler. I'm… not entirely convinced that they get better results o_O
<egg> :D
<Raptop> Also, lolcadence. We're trapped on the surface of a spinning rock next to a gravitationally confined fusion reactor. You're going to have problems even at an ideal site.
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<kmath> <lbcyber> Fun fact: ⏎ ⏎ You can make any Wikipedia article dystopian by changing it to the past tense. https://t.co/UBbpJ3fgJ6
<mofh> egg: ROFL
<mofh> ++
<egg> ?
<mofh> egg: correcting the ſpelling
<egg> ah
* Raptop 🔪 the t-mobile website
<Raptop> If I mysteriously lose internet access at midnight, blame them.
<Raptop> Okay, their voice menu works.
<Raptop> Also, navigating robotic menus is deep in the uncanny valley these days
<mofh> Raptop: I find that taking a deep breath and then loudly swearing at the voice menu semi-reliably instantly takes you to a human (it varies based on company, IME).
<SnoopJeDi> Raptop, I missed Mike Brown's talk unfortunately! But my family went and I was able to introduce them to him afterwards and he even remembered chatting with me the last time he came :)
<SnoopJeDi> he was very receptive to my family cornering him and peppering him with questions for a bit
<Raptop> congratudolences
<kmath> <✔planet4589> Since I seem to have coaxed some CNES fans out of the woodwork, here is a 1966 primary source document I hadn't see… https://t.co/2VU8clwC6I
<SnoopJeDi> happily, it was largely the talk I saw anyway
<SnoopJeDi> modulo "we're done with our Subaru telescope run, but analysis takes a while so..."
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<egg> mofh: nice
<egg> mofh: meow
<egg> mofh: underlying one-step method
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<_whitenotifier-3d18> [Principia] pleroy labeled pull request #2125: Computed velocities and GRGS dialect - https://git.io/fjtqM
<_whitenotifier-3d18> [Principia] Pending. Build queued… - 
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<_whitenotifier-3d18> [Principia] Failure. Build finished. - http://casanova.westeurope.cloudapp.azure.com:8080/job/Principia/3539/
<UmbralRaptop> … why is my GR prof telling us tricks to avoid Christoffel symbols?
<_whitenotifier-3d18> [Principia] eggrobin synchronize pull request #2125: Computed velocities and GRGS dialect - https://git.io/fjtqM
<_whitenotifier-3d18> [Principia] Pending. Build queued… - 
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<UmbralRaptop> Also, will I ever get semantic satiation for "Killing vector"?
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<_whitenotifier-3d18> [Principia] eggrobin opened pull request #2126: Refer manœuvre times to a time base, not to the current time - https://git.io/fjtE0
<_whitenotifier-3d18> [Principia] Pending. Build queued… - 
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<egg|laptop|egg> UmbralRaptop: Christoffel symbols behave a bit weirdly
<galois> [WIKIPEDIA] Christoffel symbols#Transformation law under change of variable | "In mathematics and physics, the Christoffel symbols are an array of numbers describing a metric connection. The metric connection is a specialization of the affine connection to surfaces or other manifolds endowed with a metric, allowing distances to be measured on that surface. In differential geometry..."
<kmath> <eggleroy> 🌑 Fano, the new release of Principia, is out; asynchronous computation of predictions, making long predictions usab… https://t.co/kahED67uNf
<egg|laptop|egg> (the new moon was friday)
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<UmbralRaptop> egg: It's probably best to be a bit farther from the blackhole when compiling a release
<egg|cell|egg> It was released on time
<egg|cell|egg> Just tweeted late
<UmbralRaptop> birb undergoing high gravitational redshift
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<_whitenotifier-3d18> [Principia] eggrobin synchronize pull request #2125: Computed velocities and GRGS dialect - https://git.io/fjtqM
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<egg|laptop|egg> INASAN?
<egg|laptop|egg> ИНАСАН?
<galois> ИНАСАН: ИНститут АСтрономии российской Академии Наук
<egg|laptop|egg> IGN?
<galois> IGN: Institut Géographique National
<egg|laptop|egg> although now it's Institut national de l'information géographique et forestière
<egg|laptop|egg> but good luck eggstracting IGN from that
<egg|laptop|egg> !acr -add:GOP Geodetic Observatory of Pecny
<galois> Acronym already defined! Try !acr -redef:WTF When Taylor Fails
<egg|laptop|egg> GOP?
<galois> GOP: Geodetic Observatory Pecný
<egg|laptop|egg> DGFI?
<galois> DGFI: Deutsches Geodätisches ForschungsInstitut
<egg|laptop|egg> CNES?
<galois> CNES: Centre National d’Études Spatiales
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<_whitenotifier-3d18> [Principia] pleroy labeled pull request #2126: Refer manœuvre times to a time base, not to the current time - https://git.io/fjtE0
<_whitenotifier-3d18> [Principia] pleroy reviewed pull request #2126 commit - https://git.io/fjtux
<_whitenotifier-3d18> [Principia] pleroy reviewed pull request #2126 commit - https://git.io/fjtup
<_whitenotifier-3d18> [Principia] pleroy reviewed pull request #2126 commit - https://git.io/fjtuh
<_whitenotifier-3d18> [Principia] Success. Build finished. - http://casanova.westeurope.cloudapp.azure.com:8080/job/Principia/3542/
<_whitenotifier-3d18> [Principia] eggrobin synchronize pull request #2126: Refer manœuvre times to a time base, not to the current time - https://git.io/fjtE0
<_whitenotifier-3d18> [Principia] Pending. Build queued… - 
<_whitenotifier-3d18> [Principia] Pending. Building… - http://casanova.westeurope.cloudapp.azure.com:8080/job/Principia/3543/
<egg|cell|egg> Meow
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<kmath> <cdmblogs> This ultrasonic radio station broadcasts from inside an actual rat burrow and - the results will surprise you!… https://t.co/lxaa96rJVh
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<mlbaker> mofh:
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<mlbaker> i want to show you an expression that will make you cringe
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<SnoopJeDi> mlbaker, wait are you at Waterloo
<UmbralRaptop> What… how?
<UmbralRaptop> That has an infinite sum with a factorial! How does it even converge?
<mlbaker> here A is the adjacency matrix of a 3-cycle, ie {{0,1,1},{1,0,1},{1,1,0}}
<mlbaker> because it's alternating
<UmbralRaptop> (Also, J_0 doesn't have an index, but the rest of the subscripts are, right?)
<mlbaker> and for any fixed t, J_r(t) gets small very fast as r->inf
<mlbaker> J_alpha is the bessel function with index alpha
<SnoopJeDi> mlbaker, cos(tA)_ij = cos(t)A_ij, or...?
<UmbralRaptop> aaaaaaa
<mlbaker> no, cos(tA)_{ij} is what you get by taking the power series for the cosine and replacing x^r with (A^r)_{ij}
<mlbaker> er
<mlbaker> t^r (A^r)_{ij}, my bad
<SnoopJeDi> I'm trying to understand what cos(tA) means since cos() is typically defined for scalars?
<mlbaker> you take the matrix and you slam it into the power series
<SnoopJeDi> and "apply it to all the entries in this matrix" is the only sensible thing I can think of?
<mlbaker> right, so it doesn't quite work like that because (A^k)_{ij} =/= (A_{ij})^k
<mlbaker> except for like, diagonal A
<SnoopJeDi> mmhmm
<SnoopJeDi> OH
<SnoopJeDi> I see what you're saying
<SnoopJeDi> so cos(tA) is itself a map, got it
<UmbralRaptop> aaaaaαααα
<SnoopJeDi> (I feel like this is a Very Obvious Linear Algebra™ thing that I may have known once and forgotten?)
<mlbaker> btw, it turns out that expression is [e^{-2it}(1+2 e^{3it})]/3
<mlbaker> which is... much easier to compute...
<mlbaker> oh sorry, i mean it's the real part of that thing
<SnoopJeDi> OH YES OKAY
<SnoopJeDi> I've definitely seen e^A before and naturally e^iA under that understanding lets you understand cos/sin
<SnoopJeDi> (at least algebraically)
<mlbaker> yeah
<mlbaker> I need to figure out a systematic way to rewrite the former type of thing to the latter type of thing whenever possible
<mlbaker> so that I can actually evaluate this shit >_>
<mlbaker> I guess I could just approximate the graph's eigenvalues and then analyze the exponential by diagonalizing
<SnoopJeDi> oo, what sort of graph are you working on?
<mlbaker> cycle graphs of arbitrary size
<SnoopJeDi> also, Waterloo? (just curious since we haven't interacted much)
<mlbaker> alma mater
<SnoopJeDi> ah. you and mofh know each other irl maybe?
<mlbaker> yep
<SnoopJeDi> neato :)
<SnoopJeDi> (lucky you!)
<SnoopJeDi> mlbaker, I was doing a tiny bit of cycle explanation to someone who wasn't quite getting it in a Python channel last week
<mlbaker> cycle graphs?
<SnoopJeDi> they were puzzling over the itertools documentation for permutations(), which is a very ugly direct translation of the relevant CPython, which requires some Deep Evil™.
<SnoopJeDi> yea, if you're computing n-choose-k with the algorithm used in CPython, you're exploring nested cycles
<mlbaker> hmm
<mlbaker> isnt n choose k easy to compute by just like...
<SnoopJeDi> so once you've chosen (k-1) things, you have (n-k) choices remaining
<SnoopJeDi> and it does this by storing indices in a list and running through the cycle
<SnoopJeDi> (shuffling indices)
<SnoopJeDi> mlbaker, to be clear I mean the permutations themselves not the number of them
<mofh> mlbaker: aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
<SnoopJeDi> i.e. [(a, b, c), (a, c, b), (b, a, c), (b, c, a), (c, a, b), (c, b, a)]
<mlbaker> hahahahaha
<mlbaker> this is the general expression i derived for the transition probabilities of a quantum walk on a cycle
<mlbaker> after deriving it i then realized it's the most useless expression ever
<SnoopJeDi> and CPython (and the godawful "roughly equivalent" Python code in the docs) does this by an algorithm that walks cycles in the same way an odometer does, basically
<mofh> yeah I'm legitimately at a loss for when it would be useful
<SnoopJeDi> (it gives permutations in lexicographical order)
<mofh> like Bessel series *can* be useful but what the hell is even the *purpose* of this one?
<mlbaker> all i did was basically combinatorially reason out the number of length r walks between any two vxs
<mlbaker> and then yah just plug those counts into the exponential series
<SnoopJeDi> mofh, did you see http://ratradio.nyc/ it is extremely important
<SnoopJeDi> I am getting nothing done bc I'm listening to it
<mlbaker> and some nice lil 0F1(...)s pop out
<SnoopJeDi> mlbaker, what's the elevator-talk for the transition probabilities you're exploring?
<mlbaker> quantum walks on cycle graphs
<mofh> "nice lil 0F1(...)s"
<mofh> that's kinda an oxymoron imho
<mofh> :p
<mlbaker> XD
<SnoopJeDi> I got that part, but why? Looking at some interaction to such-and-such order?
<SnoopJeDi> (this is just curiosity, I'm trying to get in the habit of practicing scicomm skills)
<mlbaker> trying to study whether there are any times t where all transition probabilities are 1/N
<mlbaker> ie 'uniform mixing' occurs
<SnoopJeDi> ah okay, I've definitely heard that phrase before
<_whitenotifier-3d18> [Principia] pleroy closed pull request #2126: Refer manœuvre times to a time base, not to the current time - https://git.io/fjtE0
<_whitenotifier-3d18> [Principia] pleroy pushed 3 commits to master [+0/-0/±6] https://git.io/fjt2q
<_whitenotifier-3d18> [Principia] eggrobin 436e130 - refer manœuvre times to a time base, not to the current time
<_whitenotifier-3d18> [Principia] eggrobin 6d75bce - :
<_whitenotifier-3d18> [Principia] pleroy 44d75ed - Merge pull request #2126 from eggrobin/time-base Refer manœuvre times to a time base, not to the current time
<_whitenotifier-3d18> [Principia] pleroy closed pull request #2125: Computed velocities and GRGS dialect - https://git.io/fjtqM
<_whitenotifier-3d18> [Principia] pleroy pushed 14 commits to master [+6/-0/±40] https://git.io/fjt2O
<_whitenotifier-3d18> [Principia] eggrobin f80f7e0 - use the finite differences and test
<_whitenotifier-3d18> [Principia] eggrobin 364d281 - the trajectories are discontinuous...
<_whitenotifier-3d18> [Principia] eggrobin 1e713df - the test passes
<_whitenotifier-3d18> [Principia] ... and 11 more commits.
<UmbralRaptop> !8 Can I convince my GR prof that we should watch the EHT announcement in class?
<galois> UmbralRaptop: yes
<SnoopJeDi> if your prof needs much convincing of that, I...
<SnoopJeDi> well, then just watching it on your phone >:)
<SnoopJeDi> just made the reminder for our Slack
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<UmbralRaptop> I assume that someone like iximeow has to watch it at 6 am. (Bring eggstra coffee?)
<mlbaker> ah, I screwed up. the factorials shouldn't be there :P
<UmbralRaptop> ∀∀∀∀∀∀∀∀∀
<egg|laptop|egg> !u ∀
<galois> ∀: U+2200 FOR ALL
<egg|laptop|egg> !u A
<galois> A: U+0041 LATIN CAPITAL LETTER A
<egg|laptop|egg> !u 𓃾
<galois> 𓃾: U+130fe EGYPTIAN HIEROGLYPH F001
<iximeow> UmbralRaptop: i might just
<egg|laptop|egg> whitequark: remember how the TT/TAI/UTC/UT1 literals were added for the purposes of tests?
<egg|laptop|egg> whitequark: and silly directory as well https://github.com/mockingbirdnest/Principia/tree/master/astronomy/standard_product_3
<_whitenotifier-3d18> [Principia] pleroy opened pull request #2127: Add support for editing burn parameters using a text field - https://git.io/fjtw7
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<egg|laptop|egg> mofh: meow
<egg|laptop|egg> mofh: underlying one-step method
<egg|laptop|egg> mofh: meow
<kmath> <erik_kwakkel> Cows singing from a songbook on a lectern (Cambrai BM 127, dated 1542). https://t.co/zkux8VRVf2
<kmath> <enf> If anyone was curious what a (1950s) programming language looks like when you start from French instead of English,… https://t.co/hHSTwnskGp
<mofh> egg|laptop|egg: meow, gotcha, meow, sec.
<egg|laptop|egg> ALGOL!
<egg|laptop|egg> whitequark: iirc there was also ru ALGOL?
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<_whitenotifier-3d18> [Principia] pleroy synchronize pull request #2127: Add support for editing burn parameters using a text field - https://git.io/fjtw7
<_whitenotifier-3d18> [Principia] Pending. Build queued… - 
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<_whitenotifier-3d18> [Principia] eggrobin reviewed pull request #2127 commit - https://git.io/fjtrN
<_whitenotifier-3d18> [Principia] eggrobin reviewed pull request #2127 commit - https://git.io/fjtrA
<_whitenotifier-3d18> [Principia] eggrobin reviewed pull request #2127 commit - https://git.io/fjtrx
<_whitenotifier-3d18> [Principia] eggrobin reviewed pull request #2127 commit - https://git.io/fjtoI
<_whitenotifier-3d18> [Principia] eggrobin reviewed pull request #2127 commit - https://git.io/fjtoL
<_whitenotifier-3d18> [Principia] eggrobin reviewed pull request #2127 commit - https://git.io/fjtot
<_whitenotifier-3d18> [Principia] eggrobin reviewed pull request #2127 commit - https://git.io/fjtoq
<egg|laptop|egg> TOPEX?
<galois> TOPEX: Topography Experiment for Ocean Circulation
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<egg> mofh: meow
* egg|laptop|egg swats mofh
<egg|laptop|egg> mofh: https://en.wikipedia.org/wiki/List_of_BeiDou_satellites is a fun constellation
<galois> [WIKIPEDIA] List of BeiDou satellites | "This is a list of past and present satellites of the BeiDou/Compass navigation satellite system. As of November 2018, 33 satellites are operational: 6 in geostationary orbits (GEO), 6 in 55-degree inclined geosynchronous orbits (IGSO) and 21 in Medium Earth orbits (MEO). Furthermore, 6 satellites (3..."
<mofh> Wait, they have BeiDou in GEO? That seems weird for a GNSS system
<egg|laptop|egg> mofh: early satellites, as well as inclined GSO
<egg|laptop|egg> mofh: also the proliferation of satellite designators is confusing
* egg|laptop|egg pokes 东方红 with a stick
<mofh> egg|laptop|egg: huh, interesting.
<egg|laptop|egg> mofh: what is interesting, i keep saying unrelated things,
<egg|laptop|egg> aaaaaaa transliteration 伽利略
<egg|laptop|egg> (as in 伽利略定位系統)
<mofh> egg|laptop|egg: Soviet Republic the game :p
<egg|laptop|egg> ah
<egg|laptop|egg> mofh: eggstremely nice seleggtion of vehicles too
* egg|laptop|egg might have covered the roads in T138 variants,