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>
!wpn
* Qboid
gives egg a berkelium ?
* egg
is transconjugated
* egg
is sad that English doesn't have the word "transconjugate" for "conjugate transpose"
<egg>
bofh: it doesn't, right
<egg>
(French has transconjuguée)
<bofh>
egg: it does not
<bofh>
tho I usually use "Hermitian conjugate" for that.
<egg|zzz|egg>
(unfortunately Sarbian's integrator is bad and clearly at some point this should just call the principia integration libraries https://imgur.com/NOLs61p)
<bofh>
whitequark: yeah it's 100% safe at those doses
<bofh>
whitequark: I'm actually fairly certain all it'd do for a non-attention-deficit cat is keep them awake slightly longer.
<bofh>
LOL THE CODE
<bofh>
"we are orbiting cats on a loading screen, so I guess I can live with it"
<egg|zzz|egg>
bofh: but Sarbian knows that bad numerics will invoke the wrath of the egg
<bofh>
Indeed, apparently!
* bofh
is thankful their numerics code is well-written
<bofh>
I propose that "pants decomposition" get added as a wpn
<egg|zzz|egg>
is pair of pants already a wpn
<egg|zzz|egg>
bofh: also is it called a pair of trousers in en-GB
<bofh>
LOL I wonder, not sure tbh
<egg|zzz|egg>
also I like how it shows how to construct a surface with >= 2 holes and constant negative curvature with right-angled hexagons
* egg|zzz|egg
<3 right-angled hexagons
<bofh>
Nice.
<egg|zzz|egg>
(cut 4g-4 right-angled hexagons out of a hyperbolic plane, sew them pairwise to get 2g-2 pairs of pants, sew that to get your surface; at every corner four right angles meet, so you do indeed have a surface of genus g with constant negative curvature)
<bofh>
rofl my mind immediately interpolated in "cut 4g-4 right-angled corners out of a 4-cornered simultaneous time cube...")
<kmath>
<ProbFact> In high dimensional spheres, nearly all the area is near the equator. Not really "the" equator: it doesn't matter which equator you pick!
regex has joined #kspacademia
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<egg|zzz|egg>
hm, that makes sense
<egg|zzz|egg>
(though it's hard to visualize spheres beyond S3, and S3 already involves bending one's mind with the Hopf fibration)
* UmbralRaptor
assumes that it's something like cos³(θ) bringing down the area far from the equator.
<egg|work|egg>
UmbralRaptor: yeah, just compare a circle and a 2-sphere
<egg>
trying to set up an RSS/RO save that works to test the upcoming Cayley release
<regex>
Speaking of which, I should check on procedural parts.
<egg>
it's a bit odd that starwaster can't reproduce the issue
<bofh>
egg: yaey hopf fibration
<lamont>
regex: would it make sense to fork RSS expanded and bring it into the KSP-RO github org?
<Qboid>
lamont: KevinStarwaster left a message for you in #RO [18.07.2017 08:04:49]: ""coasting to circularization burn" <--- on a sub-orbital failed injection burn... :)"
<egg>
lamont: I believe Pap just wants to add the relevant bodies to RSS
<egg>
and has a branch with that
<egg>
hasn't been merged though, try to poke Pap with the output of !wpn?
<bofh>
!wpn egg
* Qboid
gives egg a lead approximation
<bofh>
Oh, so Po-212?
<bofh>
It approximates Pb-208 given a few million years :P
<egg>
lamont: is there a build of your """PEG""" on a MechJeb targeting 1.2.2?
<egg>
(or is RSS/RO secretly 1.3-compatible)
<regex>
lamont, uh, maybe? The real problem is that Principia only supports a subsection of everything it covers.
<regex>
I install it for Ceres and Vesta though.
<regex>
which really need to be in RSS, IMO
<egg>
and anyway Pap wants to add eggsactly the things that principia supports
<lamont>
can clearly use that to plan transfers to lagrange points, but once the ship gets there you’re on your own…
<egg>
yeah, and even there it's not necessarily the best way to get there
<lamont>
right, flinging it out to the edge of Earth’s SOI and letting the Sun pull on it
<lamont>
can’t plan that
<egg>
I mean, going to Lagrange points is fun, but a lot of the really useful stuff you can get from Principia is WSB transfers, rather than actually going to a Lagrange point
<egg>
the GRAIL trajectories are a lot of fun :-p
<lamont>
right now mechjeb simply needs to catch up with late-60s trajectory planning
<egg>
yeah
<egg>
I think for 2010s we should get it implemented in principia and then if sarbian is interested we can expose a small entry point so it can be used from MechJeb
<egg>
but esp. since we have our own idea of manoeuvres and flight plans this would be tricky to do outside principia
<lamont>
how is the flight planner currently implemented?
<lamont>
and where i’m going with this, is how do i ask principia for a property trajectory integration from c# code?
<egg>
fairly thin UI layer talks via the P/Invoke interface (generated from protos for journalling) to the C++ Plugin and the FlightPlan of the Vessel, interface likely to change all the time because so close to the UI
<egg>
lamont: it's really not designed in a way that makes it easy, and we don't really want to commit to exposing a stable API at this point (because we keep shuffling things around quite a bit)
<egg>
the underlying C++ libs are way more stable
<lamont>
yeah
<lamont>
if you can stabilize that it makes it easier to do flight planning from c#
<egg>
yeah, but I don't really think it's a good idea to have the guidance going from one to the other at that level anyway
<egg>
I'd say write an optimization/guidance in C++ on the principia libs, and have the C# ask for its results
<lamont>
its not really guidance, its just flight planning and trajectory integration
<lamont>
really just the latter
<egg>
yes except then you have to know what to optimize on the trajectory
<egg>
and returning a trajectory is going to be costly too, whereas if you can just look at it where it lives things are simpler
<lamont>
hrm
<lamont>
i guess i’ll have to see it
<egg>
whatever you return through this interface is going to have very little structure
<egg>
so you want it to be small
<lamont>
what i want is something like an Orbit class
<egg>
yeah that's not going to happen
<lamont>
well hang on
<lamont>
its not going to look exactly like an orbit, but fundamentally it starts with position + velocity vectors in a reference frame, probably with a precision for the integrator, and then be able to ask it questions like “in the next X seconds” where and when is the closest approach to the moon”?
<egg>
but your guidance on complex trajectories may want to optimize for different things, e.g. the integral over the trajectory of the difference from the actual trajectory
<lamont>
the algorithm i want to implement doesn’t care
<egg>
lamont: the algorithms you're looking at at the moment are for high-energy orbits, so there you don't care about principia anyway
<lamont>
you integrate, figure out the delta in miss in the periapsis, adjust your guess, then re-shoot
<egg>
we're talking about different problems
<lamont>
yeah, but i want to get it precise beyond just patchy conics
<egg>
and also, if I make an API, I want it to support fancier algorithms, not just what you're writing now
<lamont>
sure
<egg>
since anyway getting that API together will take months
<lamont>
but if you have a public interface to c# it opens up the API to a broader audience, you can do more with c++ but its less accessible
<egg>
lamont: also there's the more fundamental question that we also have our own manoeuvres, that are independent from the stock manoeuvres
<egg>
lamont: yes but at the moment the last thing I want is to have everybody depending on code that I constantly reshuffle and yelling at me that I broke their mods :-p
<lamont>
well yeah
<egg>
at some point I'd probably be interested in guidance for the principia manoeuvres
<egg>
and that would obviously be part of principia
<egg>
once that exists, it can be forwarded wherever as a high-level API maybe
<lamont>
heh, well i need to get the MJ code levelled up to 3D and implement apollo-era IGM at least
<lamont>
and extract that into a library for more than just ascents
<lamont>
then could translate that to C++
<egg>
possibly; in the meantime I guess I could try getting the principia flight plan to be usable from the ground up in some manner, so you can plan missions without being in a parking orbit
<egg>
but I'm not sure how that would work from a UI point of view
<lamont>
hrm
<egg>
I guess you could have a disembodied flight plan in the tracking station, start it from some combination of altitude/flight path angle/inclination/speed/etc... seems tricky :-p
<lamont>
yeah
<lamont>
i mean it’d be cool if you could figure that out
<lamont>
“summon a parking orbit to plan an injection burn"
<egg>
it would be necessary to plan things like ccar.colorado.edu/asen5050/projects/projects_2012/truesdale/img/grail.jpg
<egg>
and clearly we want cute trajectories like that
UmbralRaptor is now known as NomalRaptor
<egg>
!wpn NomalRaptor
* Qboid
gives NomalRaptor a just-in-time Glamdring
* NomalRaptor
promptly stabs things.
<NomalRaptor>
Apartment application status: ㄟ(ツ)ㄏ
<egg>
!u ㄟㄏ
<Qboid>
U+311F BOPOMOFO LETTER EI (ㄟ)
<Qboid>
U+310F BOPOMOFO LETTER H (ㄏ)
<NomalRaptor>
Moving company at least now has a date for when they'll do the estimate.
<NomalRaptor>
But I could be looking at being pushed from August 1st to 14th for move in.
* NomalRaptor
stares at the EPRV III conference (August 14-17)
<NomalRaptor>
On an unrelated note, I accept pull requests for the /topic gist.
<Fiora>
it expands roughly 30x from its original volume. a large drum of it could cause phenomenal havoc.
<Fiora>
it's also useful as a fairly cheap source of arbitrary amounts of foam (which can be carved into shapes) or just in general a way to hold things in place via pressure.
<NomalRaptor>
ah
<bofh>
goddamnit the You Spin Me Right Round percussion track is astoundingly complicated (try following along clap, cowbell & hihat at the same time! it's great fun!)
<bofh>
a lot of this is doing a wonderful job reminding me I have zero useful perception of rhythm or timekeeping.
<bofh>
Which isn't *surprising*, but still aggravating.