raptop changed the topic of #principia to: READ THE FAQ: http://goo.gl/gMZF9H; The current version is Fréchet. We currently target 1.5.1, 1.6.1, and 1.7.x. <scott_manley> anyone that doubts the wisdom of retrograde bop needs to get the hell out | https://xkcd.com/323/ | <egg> calculating the influence of lamont on Pluto is a bit silly… | <egg> also 4e16 m * 2^-52 is uncomfortably large
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lpg. — it's pretty unusual in the greater scheme of things
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rsparkyc. — Ok, I'm really at a loss here as far as performance goes. quoting @egg
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rsparkyc. — > it can be slow when timewarping very fast, other than that it’s a question of not asking it to compute more than you need (with respect to trajectory predictions etc.)
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rsparkyc. —
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rsparkyc. — My current save has 4 vessels in flight and I'm trying to launch a 5th, but performance right off the launchpad is abysmal (nearly a 5:1 ratio, and not in the good way...) I made a copy of my install, deleted principia, and relaunched the same vessel, and everything was super smooth, which leads me to believe that principia is killing my performance, even when NOT timewarping.
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rsparkyc. — I've confirmed that I have my my tolerance and steps turned all the way down
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egg. — How is memory usage with vs without Principia
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rsparkyc. — 16.48G w/ principia, let me boot up the other one and see
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Myshiko. — @rsparkyc you want tolerance up, not down. You really do not need milliliter level precision. Just make tolerance to be 1 meter, and you are good to go.
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Myshiko. — @rsparkyc you want tolerance up, not down. You really do not need millimeter level precision. Just make tolerance to be 1 meter, and you are good to go. (edited)
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rsparkyc. — ahh, i may have slid that the wrong way
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egg. — Yes but steps is the amount of work
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egg. — Lowering the tolerance will give you a shorter prediction for the same work but not cost more
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egg. — Nor less
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rsparkyc. — ahh, hence why the lines get longer when you raise the tolerance
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rsparkyc. — so that slider shouldn't matter in this case
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egg. — Indeed
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egg. — Performance being bad out of time warp and out of map view makes no sense...
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egg. — Any exception spam?
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rsparkyc. — nope
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rsparkyc. — let me make sure those get shown without alt-f12 to be sure
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egg. — What happens if you open the cheat page of the debug menu, does performance improve
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egg. — also can you send me an INFO log, just in case there’s something useful in there
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rsparkyc. — yeah, let me make sure that's turned on, i had turned some logging down to see if that would help
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rsparkyc. — cheat page doesn't seem to help, confirmed no exception spam, recalculated the "slowness" to be about 3:1
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rsparkyc. — basically i can see mecjeb's deltaV counter show how much burn time i have left, and it goes through about 0.3 seconds in one real world second
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egg. — try Ferrari (adding it to a save from which you removed Principia, since we do not support downgrading saves)
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rsparkyc. — ok, let me pull that done
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rsparkyc. — ok, let me pull that down (edited)
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egg. — and if that is noticeably faster then we can try figuring out who the culprit is
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egg. — if it's not faster we would have to look at 1.6.x to be able to look at older versions
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rsparkyc. — i take it saving the game in the game w/o principia will wipe any old principia save data from the save?
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egg. — I think it will
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rsparkyc. — cool
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egg. — you can check that the save becomes much smaller
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rsparkyc. — yeah, that's what i was going to do
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egg. — if it does, Principia probably went away
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rsparkyc. — hrmm...persistant looks the same (103megs), let me load and resave again
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egg. — hm
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egg. — you might have to remove the principia node by hand if that doesn't work
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egg. — which is annoying
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rsparkyc. — yeah, let me see what a quicksave does
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rsparkyc. — i may have not gotten a new persistant save when i quit?
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rsparkyc. — will know in about a minute
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rsparkyc. — I really wish i could hibernate specific apps, that way i could run both versions at the same time and just resume the one i want to test
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rsparkyc. — nope, quicksave is still 103 megs
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rsparkyc. — I take it i delete the PrincipiaPluginAdapter scenario
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rsparkyc. — is that the only thing?
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rsparkyc. — it's down to 4 megs now...
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rsparkyc. — booting up with ferrari, will test performance, let you know, but then i got to head to bed
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rsparkyc. — ok, it seems much better now, i'll try to nail down what version i see the performance degraded
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rsparkyc. — i'll keep you posted, thx for helping me debug
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<_whitenotifier-d13c>
[Principia] pleroy commented on issue #1639: Spacecraft orientation change during parent body transition - https://git.io/JvDfq
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[Principia] pleroy tagged f0b8e69 as 2020032409-Frobenius https://git.io/JvDUu
<_whitenotifier-d13c>
[Principia] pleroy created tag 2020032409-Frobenius - https://git.io/fpDwq
<kmath>
YouTube - Principia Frobenius—Джанибеков effect in time warp
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egg. — @Damien re. your bug :-p
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Damien. — That is unbelievably cool
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Sir Mortimer. — 🤤
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neph. — 🎊🎉🎊🎉🎊🎉🎊
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Stonesmile. — so is there anything from "real physics" missing from principia now?
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Transparent_Elemental. — something that is not yet explained by physics i guess
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Stonesmile. — solar radiation preassure?
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Transparent_Elemental. — what is that flipping from one side to the other is about on Джанибеков effect video?
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Transparent_Elemental. — @Stonesmile i think standecco was doing something related to solar sail
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Stonesmile. — Джанибеков effect is more commonly known in the west as the intermediate axis theorem
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Transparent_Elemental. — i know almost nothing in physics in my native language, let alone foreign 🙂
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Transparent_Elemental. — is that part of the effect too?
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Stonesmile. — teh most common example of this is a tennis racket, you can't spin it in a certain direction without it spinning in another, i recommend looking it up on youtube. I think Veritasium has a video about it
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Stonesmile. — the most common example of this is a tennis racket, you can't spin it in a certain direction without it spinning in another, i recommend looking it up on youtube. I think Veritasium has a video about it (edited)
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Transparent_Elemental. — glad there's also a ksp video about it
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egg. — yeah SRP and other related effects are entirely missing
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egg. — YORP!
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egg. — @Transparent_Elemental the flipping *is* the Джанибеков effect
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egg. — see the video linked in the description
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egg. — Relativity is an obvious one, too (but much less significant than SRP)
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rsparkyc. — i beat you to it!
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egg. — indeed
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egg. — thou ninjaest me
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Transparent_Elemental. — i already watched a video explaining it, as i said i know almost nothing about physics so i thought that the rotation slowing down was that Джанибеков effect 🙂
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rsparkyc. — lol
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egg. — ah no the rotation slowing down is in the other video
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egg. — from moving fuel inward as the arms of a figure skater
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Transparent_Elemental. — no, you decoupled two beams in that video and it slowed down
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egg. — no, the decoupling doesn’t slow it down
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egg. — it slows down a bit before that because I go out of timewarp
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egg. — but that’s not really physics, is it :-p
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Transparent_Elemental. — my eyes tricked me 👀
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egg. — Oh also re. missing effects, atmospheric drag
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Stonesmile. — you mean atmospheric drag in LEO?
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egg. — yeah
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Stonesmile. — i can live without that, some might want it tho, to introduce the need to re-boost space stations
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Standecco. — `drag = true` in the principia code should do the trick
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egg. — hah where does that meme come from again ? I forget
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Standecco. — probably the suggestion of having nbody as a toggle in ksp 2
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Standecco. — "suggestion"
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Myshiko. — The official build of Frobenius, I assume it’s coming soon, right?
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egg. — yeah the new moon is on the morning of the 24th
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Butcher. — Will this be in the new build?
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Myshiko. — I feel like werewolf, waiting the the moon.
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Myshiko. — I feel like werewolf, waiting for the moon. (edited)
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Butcher. — Nice, I can get rid of persistent rotation then.
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Stonesmile. — I just noticed a 'frobenius' version in the releases on github, is that a test version or does it work?
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Agathorn. — Can you do sun synchronous orbits in Principia?
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Stonesmile. — @Agathorn yes, with RSS
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Standecco. — @egg can you hold a orientation relative to a body? For example, keep pointing prograde as you orbit around earth?
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egg. — not actively, no stationkeeping including in attitude
<_whitenotifier-d13c>
[Principia] pleroy commented on issue #2365: Investigate Cholesky decomposition for symmetric bilinear forms - https://git.io/JvDqv
<_whitenotifier-d13c>
[Principia] pleroy closed issue #2365: Investigate Cholesky decomposition for symmetric bilinear forms - https://git.io/JeEKQ
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Transparent_Elemental. — @Agathorn i'm pretty sure it's possible exclusively with principia
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Agathorn. — Yeah there is no way it would work in KSP alone that's why I asked. Since it relies on modelling the oblateness of the Earth pulling on the spacecraft
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Transparent_Elemental. — also with principia orbits rotate over time which is not the case with 1-body physics
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Acer_Saccharum. — the orbits rotating is a single-body effect, but an extended-body effect
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Agathorn. — well they don't rotate over time BECAUSE of what I said above 🙂 That rotation comes from the fat earth pulling (or pushing?) on the orbit
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Acer_Saccharum. — you can definitely do sun synchronous orbits
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Acer_Saccharum. — Principia has at least a 10th degree (might be more, haven't checked in a while) geopotential model for earth
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neph. — It's highly accurate
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Transparent_Elemental. — *well you know what i meant*
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Agathorn. — Equal to a 12th level intellect?
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neph. — Does rotation adhere to the IAT outside of timewarp as well?
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RurouniDonut. — That’s fucking cool
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Acer_Saccharum. — it does in stock KSP at least
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