UmbralRaptor 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> … one of the other grad students just compared me to nomal O_o | <ferram4> I shall beat my problems to death with an engineer.
<egg> bofh: it's the interior product
<egg> UmbralRaptor: wonderful mathematical terminology: inner product, interior product, exterior product, outer product are four different things :D
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<egg> in french those translate to scalar, interior, exterior, and dyadic, so I guess this may be the result of a merger of translations?
<bofh> egg: wait, *interior* product? I've never heard of that before.
<bofh> also, associative wrt wedge?!?
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<egg> bofh: well not sure about this associativity, this is quite messy to look at
<egg> bofh: basically once you pick an orientation (aka a normed trivector), the hodge star is precisely that thing
<egg> so the "tv" and "tb" above are i_v t and i_b t
<egg> bofh: and now out of just trying to get the shortest vector joining two lines you have discovered a new kind of fancy product :D
<Iskierka> ... apparently freecad will allow you to slide components to any float position, but not define a constraint of .01 mm precision?
<Iskierka> ... or maybe it will if you do it a different way. No idea what the C++ exception was about
<whitequark> fucking freecad
<whitequark> how can anyone tolerate that pile of shit
<Iskierka> Iiii don't know as I just picked something the internet pointed to since I can't afford solidworks that I have non-zero experience with
<bofh> egg: ...okay I kinda see this now.
<Iskierka> does you have better recommentation?
<Iskierka> because I've spent half an hour trying to model a servo horn to model a mounting and so far I have a cylinder and *almost* a sketch of one arm cross-section
<whitequark> Iskierka: there's solvespace, which is what I started to maintain after being *almost* convinced by freecad that I'm too dumb to ever use CAD
<whitequark> solvespace.com
<whitequark> some people say it's good
<whitequark> the major issue is that there are some operations you can't do (lofting, filleting, frustums are the major issues)...
<whitequark> and the underlying NURBS backend isn't super robust, so sometimes you'll have to twiddle it a bit
<whitequark> but it's like 150% more functional than freecad was at any point in its development history
<Iskierka> hrm. I don't know if it's necessary but lofting was one of the things I was intending to get the horn modelled
<whitequark> that might be a problem, yes. some lofted shapes can be approximated with a little effort, some can not
<whitequark> okay I'm really impressed with this cat's ability to play without claws
<egg> bofh: I'm not sure what the inner product with lower-grade multivectors means, but with the volume form it seems to be that
<whitequark> I'm straight out teasing it by scratching the bedsheets
<whitequark> and it has never once pierced my skin with either claws or fangs
<egg> whitequark: котя I assume, not эта хуйня?
<bofh> egg: isn't it just the wedge product?
<whitequark> egg: yes
<whitequark> also it was too anxious so we fed it some cat anxiolytics
<egg> bofh: um, I don't think so, the return type is wrong (the grade of the result is the difference, not the sum, of the grades)
<whitequark> there's a weird soviet drug called phenibut that i was taking because of anxiety
<bofh> I'm pretty sure if эта хуйня claws you you'll prolly need to go on strong antibiotics
<whitequark> well turns out cat anxiolytics is ALSO phenibut
<bofh> egg: erm, shouldn't the difference of the grades and the sum of the grades be the same *type*?
<bofh> since difference is equal to sum of negation and negation doesn't change type
<whitequark> and that works ridiculously well
<Iskierka> it's late to carry on now but I'll try solvespace tomorrow. If I can model the horn I probably don't need too much else, just designing a bracket to hold a rangefinder
<whitequark> in fact it works a great fucking deal better than on humans, which makes me pretty bitter about the whole thing
<egg> bofh: uh, the grade is always positive (in the french sense, including 0)?
<egg> bofh: by type I mean the boring programming sense
<whitequark> egg: what happened to "nonnegative"
<egg> whitequark: in france you don't say that, but it would mean strictly positive (so you don't say it, you say strictly positive)
<whitequark> bofh: someone on twitter recommended taking a course of plaquenil as if I had acute malaria, against various piroplasms it may or may not carry in its various fleas and ticks
<whitequark> since any medical advice given by a person with a handle "@lesbiologist" is clearly good that's what i did
<egg> also I need to set up a cyrillic keyboard layout so I can type cat names
<whitequark> I also don't touch эту хуйню without gloves
<egg> yeah that seems sane
<bofh> egg: ohh, the grade is necessary +ve semidefinite?
<whitequark> speaking of, this morning i discovered two^Wthree more sites of cat diarrhea
<egg> bofh: ok now I'm confused
<whitequark> if it goes the same this bathroom is going to be declared a Superfund site
<bofh> whitequark: well seeing as cat contraceptives are basically $PROGESTIN, not surprised cat anxiolytics are phenibut.
<bofh> egg: sec, same, let me rephrase
<egg> whitequark: [extremely CSB face] the Cat Shit Board recommends that printer promptly take эту хуйню to the veterinary
<whitequark> bofh: there are also cat tranquilizers (lorazepam) and cat anticonvulsants (sodium valproate) and...
<whitequark> you see where this goes
<whitequark> I'm actually yet to see any cat drug that's not just a human drug in a liquid form in small dosage
<egg> (are we just cats)
<bofh> egg: okay, so your index sets always have to be consisting only of nonnegative integers? huh
<bofh> whitequark: huh. go figure.
<whitequark> it seems extremely unsurprising that the submilligram dose of ethylphenidate printer gave the cat did exactly what you would expect if you consider it divided by body weight.
<egg> bofh: what index sets? I'm confused
<egg> bofh: maybe I misused the word grade?
<egg> Oh maybe I meant rank
<bofh> egg: you're referring to some I-graded module we're defining our ext--OHHHHHHH
<bofh> RIGHT FRENCH
<bofh> sorry :/
<bofh> things make more sense now tho
<bofh> and okay yeah rank is by definition obviously nonnegative :P but in that case hm
<whitequark> egg: lol Cat Shit Board
<egg> bofh: not sure it's french so much as confusing a pile of Wikipedia articles, I never did this stuff in french
<bofh> whitequark: yeah, that it does. also thanks for answering my question of "what happens when one feeds a cat EPH" :P
<Iskierka> is this basically the news that all mammals are basically the same when it comes down to it?
<whitequark> same with the rats, I've heard, but I mean *that* part is obvious
<whitequark> a friend was stuck with the unenviable job of dividing her own contraceptives to feed it to a rat
<egg> also TIL I have the means to deal with an epileptic cat :-p
<whitequark> egg: or a bipolar cat
<whitequark> I don't recall reading about cats with bipolar disorder, but since cats get anxiety disorder, panic attacks and depression
<whitequark> ... in case you're wondering, yes, there's cat fluoxetine...
<bofh> how does one tell if a cat is depressed anyhow?
<whitequark> it seems logical that there are bipolar cats too
<Iskierka> you mean fluoxetine cut up super tiny?
<whitequark> bofh: uncharacteristic lack of activity
<whitequark> basically
<whitequark> Iskierka: pretty much
<egg> "uncharacteristic lack of activity" in a cat seems like a high bar
<whitequark> egg: well if a cat suddenly decides to barely move from its place for weeks and doesn't eat, and there's no organic cause
<whitequark> you might as well feed it SSRIs and see what happens? I suppose?
<whitequark> it does seem to work well enough
<egg> makes sense
<whitequark> it's not like there's a rule that says "must have this much dedicated to neocortex to get depression"
<whitequark> although it certainly seems to *help*...
<egg> bofh: it's not french though, in french the rank is called rang, easily enough; not sure how I shoved the word grade into there
<bofh> ahh.
<bofh> whitequark: also I was just watching more CSB videos and OH GOD VAPOUR CLOUD OF 10KG OF OLEUM *WHY*
<egg> bofh: though isn't the exterior algebra graded?
<bofh> egg: it by definition has to be
<egg> bofh: is the grading the rank, or am I confused?
<bofh> egg: I think I'm confused tbh
<egg> bofh: aha, so i_u(v∧w)=⟨w,u⟩v-⟨w,v⟩u=u(v∧w), it's just matrix multiplication here
<bofh> huh.
<bofh> that seems unusually simple
<egg> bofh: so the other interior products is the matrix multiplication; but the matrix multiplication is the only one that is also a multiplication thanks to the isomorphism with ??(?)
<egg> s/ducts/duct
<Qboid> egg meant to say: bofh: so the other interior product is the matrix multiplication; but the matrix multiplication is the only one that is also a multiplication thanks to the isomorphism with ??(?)
<egg> (probably)
<egg> (cetacean needed)
<egg> I should zzz
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* UmbralRaptor gives egg|zzz|egg an Orcus worshipping orca.
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<egg|zzz|egg> !wpn UmbralRaptor
* Qboid gives UmbralRaptor a Norman engineer-like inexplicable popup that didn't used to be there and doesn't do what it used to
* UmbralRaptor wonders what [awake, asleep] equals.
<egg|zzz|egg> UmbralRaptor: :D
<egg|zzz|egg> !wpn -add:wpn bracket
<Qboid> egg|zzz|egg: Weapon added!
<egg|zzz|egg> !wpn -add:adj Lie
<Qboid> egg|zzz|egg: Adjective added!
<egg|zzz|egg> UmbralRaptor: is the label on falafel's box accurate?
<UmbralRaptor> !wpn -add:wpn commutator
<Qboid> UmbralRaptor: Weapon already added!
<UmbralRaptor> egg|zzz|egg: somewhat, Falafel isn't the brightest cat.
<egg|zzz|egg> UmbralRaptor: have you seen this stupid user https://github.com/mockingbirdnest/Principia/issues/1448
<Qboid> [#1448] title: ksp realism overhaul crash | // Temp fix: apply crew mass in VAB/SPH... | https://github.com/mockingbirdnest/Principia/issues/1448
<egg|zzz|egg> UmbralRaptor: click through to their account, it's hilarious
<egg|zzz|egg> they did a *pull request* with that same config file on something called KSCrash, which is an iOS crash reporter (nothing to do with KSP of course) :D
<egg|zzz|egg> I think this is a new record of stupiduseriness
<egg|zzz|egg> UmbralRaptor: otoh we've been getting a lot of good bug reports from maccollo, rsparkyc, scimas et al.
<egg|zzz|egg> also lawndart
<UmbralRaptor> o_O
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<egg|afk|egg> !tell bofh more on the interior product, with a strange notation http://mathworld.wolfram.com/InteriorProduct.html
<Qboid> egg|afk|egg: I'll redirect this as soon as they are around.
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<egg|work|egg> !wpn Thomas
* Qboid gives Thomas a pyrolytic cube which vaguely resembles a pilcrow
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* UmbralRaptor ? Portland in the traffic.
<egg|work|egg> !wpn UmbralRaptor
* Qboid gives UmbralRaptor a rocky thorium carrot
<UmbralRaptor> !wpn egg|work|egg
* Qboid gives egg|work|egg a shippy checker
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<egg> !wpn UmbralRaptor
* Qboid gives UmbralRaptor an isobaric tensor/equation hybrid
<kmath> <zwnj> Introducing UNIC: Unicode and Internationalization Crates for @rustlang, coming with @unicode 10.0.0 released today! https://t.co/yYHedrx7T8
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<egg> bofh: oh crap, even the interior product which *is* matrix multiplication should not be written *, because with implicit musical isomorphisms things don't associate!
<egg> so I guess all my *s should be interior products
<bofh> egg: wait, what? interior products fail to be associative under certain cases? how?
<Qboid> bofh: egg|afk|egg left a message for you in #kspacademia [21.06.2017 08:08:47]: "more on the interior product, with a strange notation http://mathworld.wolfram.com/InteriorProduct.html"
<egg> bofh: hmmm oh I guess that's only if you allow them to be defined symmetrically?
<egg> bofh: essentially, I just realized that bivector * vector * other_bivector doesn't associate (because in coords it's three vector products!)
<egg> bofh: also the interior product also encompasses the inner product, right? and that doesn't associate with vector*scalar multiplication...
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<egg> !wpn pizzaoverhead
* Qboid gives pizzaoverhead a contravariant pommel
<pizzaoverhead> !wpn egg
* Qboid gives egg a hypergolic transistor
<egg> bofh: hmm, so if you define it only where left rank <= right rank, it might associate?
<egg> but then you can't have vector * scalar, or bivector * vector
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<bofh> egg: brb in 2hrs, will reapond then
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<egg> wait no, it just *doesn't* associate.
* egg briefly considers differentiating vectors and covectors
* egg stares at the madness
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<kmath> <rygorous> @FioraAeterna That said I will note that this qualifies both as initial success _and_ as total failure.
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<kmath> YouTube - Playing fetch with Tuco the Cat