egg changed the topic of #principia to: Logs: https://esper.irclog.whitequark.org/principia | <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…
<queqiao->
⟨egg⟩ rnlahaye I am deeply confused as to how those fancy apple devices work; you say KSP is x86_64 only, how does it even run there then? And if it somehow does, can we not likewise run in is x86_64?
<queqiao->
⟨egg⟩ -is
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<queqiao->
⟨egg⟩ But then this thing will translate our vectorized code to vectorized code, right?
<queqiao->
⟨egg⟩ (from one SIMD ISA to another)
<queqiao->
⟨lpg⟩ that's beyond my knowledge
<queqiao->
⟨egg⟩ whereas if we drop that, we eat a factor of two (since we are using SSE2 right now)
<queqiao->
⟨lpg⟩ oof. and reading the issue, the suggestion is to run principia as a separate process so that _it_ can run native even if ksp is under rosetta
<queqiao->
⟨egg⟩ (probably more like 3/2 than 2, but still, vectorization was a nice speedup)
<queqiao->
⟨egg⟩ I would be surprised if just dropping the intrinsics and running natively were to improve performance (having a version with AMD intrinsics is another question, of course)
<queqiao->
⟨lpg⟩ ARM
<queqiao->
⟨egg⟩ er yes
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<queqiao->
⟨egg⟩ wrong three-letter semiconductor company
<queqiao->
⟨rnlahaye⟩ Regarding https://github.com/mockingbirdnest/Principia/issues/3019, I suspect that using Apple's SIMD libraries might help. I have a pre-Sandy Bridge mac and a post-Sandy Bridge hackintosh, so I should be able to determine this without too much difficulty. That won't help with Linux though.
<queqiao->
⟨egg⟩ ⟪rnlahaye⟫ Regarding https://github.com/mockingbird[…] ⮪ Well, there’s Windows too. The basic issue is that the entire binary (or anything that does floating-point maths, but we don’t do much else here) wants to be different for AVX, so we pretty much need two DLLs.
<queqiao->
⟨egg⟩ (it’s probably saying it doesn’t have AVX, apparently Rosetta2 has SSE2 but no AVX)
<queqiao->
⟨egg⟩ (it definitely has SSE2: otherwise it just wouldn’t work)
<queqiao->
⟨rnlahaye⟩ ⟪egg⟫ (it’s probably saying it doesn’t have […] ⮪ Yep, its the AVX. Rosetta2 does pretend to be "GenuineIntel" so that test passes.
<queqiao->
⟨egg⟩ lol
<queqiao->
⟨egg⟩ « Genuine »
<queqiao->
⟨egg⟩ They are limited to 12 bytes so they can’t do the user agent string exegesis thing, I guess
<queqiao->
⟨egg⟩ (and they probably run into the same problem as user agent strings)
<queqiao->
⟨rnlahaye⟩ 2010 MacBook Pro with Core 2 Duo processor
<queqiao->
⟨egg⟩ (it’s mac, so it’s not like I could run the same benchmarks I built for file://childeric/Users/robin/projects/mockingbirdnest/principia/documentation/cbrt.pdf anyway, but I had not been able to look at anything earlier back then)
<queqiao->
⟨Quadrupole⟩ So... How do you recommend Richard Battin's book on astrodynamics? How does it compare with Bate&Mueller&White or Vallado?
<queqiao->
⟨pghjh⟩ Semi off topic but Vallado is my favorite for quick reference, any recommendations for something comparable/better in that use case? Preferably with more non-keplerian things
<queqiao->
⟨egg⟩ I have never looked at any of these books, so I don’t have the faintest idea. Maybe raptop might have some advice?
<UmbralRaptop>
I wish I could offer useful commentary -- I've only used BMW in enough depth
<queqiao->
⟨pghjh⟩ Haha yeah I’m the same with Vallado. Everyone picks their favorite and sticks with it I guess
<queqiao->
⟨Kenira / River System (they)⟩ we've also only read BMW; which we liked to be fair but yeah also can't compare
<queqiao->
⟨lamont⟩ I have Vallado and Battin and recommend both, there's tricks and background in Battin that I don't think you can find anywhere else
<queqiao->
⟨lamont⟩ Vallado is probably the right modern answer if you just want one reference
<queqiao->
⟨pghjh⟩ One of my main frustrations with Vallado is that interplanetary/etc content is quite sparse
<queqiao->
⟨pghjh⟩ But then that’s kinda not really the books purpose