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
<egg|laptop|egg>
B787_300: I don't think I have been on an A350
<egg|laptop|egg>
B787_300: Vietnam airlines has some of those
<B787_300>
i havent been on A330,A340,A350, or A380.... i also havent been on B747 or B787
<B787_300>
although i was considering taking a trip out to LA to see the shuttle there and try to catch a launch from vandy that would have allowed me to fly domestic on a 787
<egg|laptop|egg>
I've been on a 747 and on a 340, not sure about 330
<galois>
[WIKIPEDIA] Airbus A350 XWB#/media/File:Airbus A350 cockpit windows (14274972354).jpg | "L'Airbus A350 XWB est un avion de ligne long-courrier et gros porteur du constructeur européen Airbus. Initialement baptisé A350, ce modèle était dérivé de l'A330 ; toutefois, à la suite des remarques des compagnies aériennes, il a été décidé à la mi-juillet 2006 d'en revoir le concept et de le munir..."
<egg|laptop|egg>
(a330 is probably but I don't recall specifically)
<B787_300>
it is the airbus equivalent of the 767/777
<egg|laptop|egg>
isn't the 777 more 340ish?
<B787_300>
yeah but the whole dual/quad engine thing
<egg|laptop|egg>
yeah
<egg|laptop|egg>
and I guess some of the 350s can fill the same roles as some of the 777s
<B787_300>
and it is so dependant on what mix of seats the airlines wants to put in
* egg|laptop|egg
should zzz
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<galois>
title: Shared album - Patrick N - Google Photos
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<UmbralRaptop>
Hrm. Wifi's iffy on the platform
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<egg>
bofh: yeah this saturday was more intense than had become usual for some reason
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<egg>
!seen bofh
<galois>
egg: I last saw bofh at 2019-03-17 - 04:41:36 in here, saying welcome to your regularly scheduled Saturday evening riots, I guess.
<_whitenotifier-3d18>
[Principia] pleroy opened pull request #2096: Change the Dialog class to persist its data using a ConfigNode - https://git.io/fjvWk
* galois
gives UmbralRaptop a rubidium linter with a pterodactyl attachment
<_whitenotifier-3d18>
[Principia] pleroy commented on pull request #2096: Change the Dialog class to persist its data using a ConfigNode - https://git.io/fjvlv
<_whitenotifier-3d18>
[Principia] eggrobin labeled pull request #2096: Change the Dialog class to persist its data using a ConfigNode - https://git.io/fjvWk
<_whitenotifier-3d18>
[Principia] pleroy synchronize pull request #2096: Change the Dialog class to persist its data using a ConfigNode - https://git.io/fjvWk
<galois>
title: Shared album - Patrick N - Google Photos
<_whitenotifier-3d18>
[Principia] pleroy synchronize pull request #2096: Change the Dialog class to persist its data using a ConfigNode - https://git.io/fjvWk
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<_whitenotifier-3d18>
[Principia] pleroy closed pull request #2096: Change the Dialog class to persist its data using a ConfigNode - https://git.io/fjvWk
<_whitenotifier-3d18>
[Principia] pleroy pushed 6 commits to master [+0/-0/±11] https://git.io/fjv8v
<_whitenotifier-3d18>
[Principia] pleroy f159a2e - Make Dialog an IConfigNode and let it persist its x and y.
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<_whitenotifier-3d18>
[Principia] pleroy 89ea9b7 - Make the rectangle a member and centre it.
<_whitenotifier-3d18>
[Principia] pleroy c9e8c23 - Persist the message inside the dialog.
<_whitenotifier-3d18>
[Principia] ... and 3 more commits.
<bofh>
egg: mew
<egg>
bofh: meow
<egg>
bofh: I have confused myself about orders of approximation
<egg>
bofh: if a finite difference formula for f'(x) has an error in O(h^k), is it a kth order or (k-1)th order formula
<bofh>
...(k-1), but now I want to double-check that.
<egg>
bofh: fornberg gives k as the "order of accuracy" but that seems disturbing
<bofh>
hm, it seems that a k'th order finite difference method seems to mean that you truncate the Taylor series at order k, meaning your error would be O(h^k), so having error O(h^k) seems to indeed imply that you have an order k-1 formula at hand.
<egg>
bofh: ... so you are saying that a kth order formula is a (k-1)th order formula
<_whitenotifier-3d18>
[Principia] pleroy opened pull request #2097: Use Unity's Scope objects and remove layout.cs - https://git.io/fjv8c
<egg>
bofh: <Ζήνων ὁ Ἐλεάτης> therefore approximation is impossible
<galois>
title: Robin Leroy on Twitter: "Grant Foster (1996), Time Series Analysis by Projection. I. Statistical Properties of Fourier Analysis. Astronomical Journal, volume 111, number 1, pages 541–554.… https://t.co/lV9tUk7Z4X"
* egg
meows at the forum https://forum.kerbalspaceprogram.com/index.php?/topic/162200-wip131-14x-151-161-principia%E2%80%94version-euler-released-2018-03-06%E2%80%94n-body-and-extended-body-gravitation-axial-tilt/&page=50&tab=comments#comment-3561670
<galois>
title: [WIP][1.3.1, 1.4.x, 1.5.1, 1.6.1] Principiaâversion Euler, released 2018-03-06ân-Body and Extended Body Gravitation, axial tilt - Page 50 - Add-on Development - Kerbal Space Program Forums
<_whitenotifier-3d18>
[Principia] pleroy opened issue #2099: We should replace the navball in IVA - https://git.io/fjvBb
<egg>
<bofh> an order k formula has error in O(h^(k-1)) << I still don't understand that convention
<egg>
(with - = + that is)
<egg>
bofh: that would make backward difference on 2 values an order 0 method, and central difference on 2 values an order 1 method?
<bofh>
Hrm, that's a good point. On the one hand that makes sense, on the other hand I usually see backward difference on 2 values being referred to--actually wait, I don't think I've ever heard of anyone referring to it by its order, other than it being one less than central difference.
<bofh>
Huh.
<bofh>
Let me check that paper (sorry, got distracted >_<)
<egg>
bofh: *flyswat*
<_whitenotifier-3d18>
[Principia] eggrobin labeled pull request #2098: Add a rectangle and locking to WindowRenderer - https://git.io/fjvBD
<_whitenotifier-3d18>
[Principia] pleroy closed pull request #2098: Add a rectangle and locking to WindowRenderer - https://git.io/fjvBD
<_whitenotifier-3d18>
[Principia] pleroy pushed 6 commits to master [+0/-0/±17] https://git.io/fjv05
<galois>
title: Principia/cbrt_test.cpp at 27e4b60e5aff8f4b8ac0a7b5ff1e676ec8efe06d · mockingbirdnest/Principia · GitHub
<bofh>
egg: someone needs to make a "signalling dead beef" photoshop of a steak now
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* UmbralRaptor
x_x
* egg|laptop|egg
pets UmbralRaptor
<egg|laptop|egg>
!meow UmbralRaptor
<galois>
喵
<egg|laptop|egg>
!meow
<galois>
喵
<egg|laptop|egg>
!help meow
<egg|laptop|egg>
bofh: MEOW
<egg|laptop|egg>
bofh: *flyswat*
<bofh>
egg|laptop|egg: yes yes
<bofh>
egg|laptop|egg: I'm seeing "of optimal formal order of accuracy (in general, n - m + 1)", so with m = 0 we have finite difference on n + 1 grid points having "order n + 1"
<bofh>
egg|laptop|egg: assuming you're talking about "Generation of Finite Difference Formulas on Arbitrarily Spaced Grids"
<egg|laptop|egg>
yeah
<egg|laptop|egg>
bofh: m=0 is interpolation
<egg|laptop|egg>
bofh: you want m=1 for the first derivative
<egg|laptop|egg>
bofh: *swat*
<bofh>
egg|laptop|egg: okay, in that case you get finite difference on n+1 points having "order n"
<bofh>
which would agree with "O(h^k) error maps to a (k-1)th order formula", no? since the error is proportional to 1 above the degree of the polynomial, I believe
<egg|laptop|egg>
bofh: what's the error on the forward difference on 2 points
<bofh>
OH, right, you divide out by h for your derivative so your truncation error is bounded by M*h/2 (for |f(x)| < M given |x-h| < some \delta), so O(h)
<bofh>
but I can see forward difference being called either first-order or zeroth-order (admittedly, I think the first is what I usually see).
<egg|laptop|egg>
bofh: yeah
<egg|laptop|egg>
bofh: that's the whole question
<egg|laptop|egg>
bofh: which one should it be
<egg|laptop|egg>
morally
<egg|laptop|egg>
!choose sleep|finite differences
<galois>
egg|laptop|egg: Your options: sleep, finite differences. My choice: sleep
<bofh>
egg|laptop|egg: thing is I can make a reasonable case for calling it either.
<bofh>
egg|laptop|egg: wikipedia claims: "As mentioned above, the first-order difference approximates the first-order derivative up to a term of order h."
<bofh>
making two-point finite difference first-order