2024/11/12

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2024-11-12 20:33:58 +0100 <EvanR> but this mindset requires respecting abstractions in play, once the game starts
2024-11-12 20:33:20 +0100 <EvanR> instead of breaking the system, maybe study ways of constructing a new system which is safe and does the optimizations
2024-11-12 20:32:56 +0100tromp(~textual@92-110-219-57.cable.dynamic.v4.ziggo.nl) (Quit: My iMac has gone to sleep. ZZZzzz…)
2024-11-12 20:31:23 +0100 <int-e> . o O ( unsuccessfullyPerformIO :: IO a -> a; unsuccessfullyPerformIO = error "I'm afraid I cannot do that, Dave" )
2024-11-12 20:30:31 +0100 <Rembane> int-e: ...while studying the dark arts?
2024-11-12 20:29:32 +0100 <int-e> avoid success at all cost?
2024-11-12 20:29:13 +0100 <EvanR> it's just not that kind of language
2024-11-12 20:29:04 +0100 <EvanR> I've never really had any success violating haskell's semantics
2024-11-12 20:28:42 +0100 <EvanR> exactly
2024-11-12 20:28:27 +0100 <bailsman> I don't though.
2024-11-12 20:28:04 +0100 <EvanR> but someone noted the existence of unsafeThaw which is your trap door into "I know what I'm doing"
2024-11-12 20:27:09 +0100 <EvanR> since it is
2024-11-12 20:27:06 +0100 <EvanR> it certainly would still be treated like a mutable array
2024-11-12 20:26:17 +0100 <bailsman> I would like most of the code to be regular normal pure code
2024-11-12 20:25:57 +0100 <bailsman> I wonder if that still causes the compiler to think the data is "actually mutable" and disables a ton of optimizations
2024-11-12 20:25:54 +0100 <EvanR> which is a different subject from increasing the performance of working with an array
2024-11-12 20:25:33 +0100 <EvanR> what I just suggested as in response to "compiler stops me from writing to it when I don't want to, because... I might accidentally write code to write to it for some reason"
2024-11-12 20:24:48 +0100 <bailsman> If that's easy to do, why isn't it how freeze/thaw already works?
2024-11-12 20:24:37 +0100sawilagar(~sawilagar@user/sawilagar) (Quit: Leaving)
2024-11-12 20:24:08 +0100 <bailsman> Interesting. Can you make an example?
2024-11-12 20:23:38 +0100 <EvanR> you can wrap your ST array in a newtype which won't allow you to write through it
2024-11-12 20:23:07 +0100 <bailsman> but I would like the compiler to ensure that I'm not writing to the data where I don't want to be writing to it.
2024-11-12 20:22:48 +0100 <bailsman> I'm totally happy to annotate all the rest of the code however the type system needs me
2024-11-12 20:22:28 +0100 <EvanR> you can access the array however you want, and the whole operation will be considered pure in the end
2024-11-12 20:22:16 +0100 <EvanR> the whole thing being an ST action sounds like what ST is meant for
2024-11-12 20:21:50 +0100 <bailsman> So what I should do instead is design it to pass mutable references around and just not write to them where I'm not supposed to?
2024-11-12 20:21:20 +0100remedan(~remedan@ip-62-245-108-153.bb.vodafone.cz) remedan
2024-11-12 20:21:14 +0100 <EvanR> but I expect the total cost to defeat the purpose of all this optimization talk
2024-11-12 20:20:52 +0100 <EvanR> since it's temporary maybe it won't be so bad
2024-11-12 20:20:29 +0100 <EvanR> see if it fits into the gc first generation
2024-11-12 20:20:20 +0100 <bailsman> I mean that was pretty much my worry, and why I was looking for whether "immutable references to mutable data" are a thing
2024-11-12 20:19:58 +0100 <EvanR> fine then
2024-11-12 20:19:47 +0100 <bailsman> it's just memcopy can't you do that at terrabytes per second or something
2024-11-12 20:19:45 +0100 <EvanR> especially if you do it once per loop and discard it all
2024-11-12 20:19:28 +0100 <EvanR> not cheap
2024-11-12 20:19:21 +0100 <EvanR> copying 100k elements?
2024-11-12 20:19:18 +0100 <bailsman> geekosaur: yes
2024-11-12 20:19:07 +0100 <bailsman> Is it? I wonder if it's going to be the fastest part, so fast that I'll be embarrased to have enough wondered about the issue.
2024-11-12 20:19:06 +0100 <EvanR> gc
2024-11-12 20:19:05 +0100 <EvanR> accessing a mutable array involves more book keeping than an immutable array, in the gd
2024-11-12 20:18:59 +0100 <geekosaur> am I understanding correctly that updateSingleElement only reads, and ultimately produces a value that the impure code will actually use to mutate?
2024-11-12 20:18:20 +0100 <EvanR> well, the frozenCopy is going to be expensive, and there's no real way around it
2024-11-12 20:17:41 +0100 <bailsman> updateSingleElement and everything it calls
2024-11-12 20:17:33 +0100 <EvanR> what pure part
2024-11-12 20:17:28 +0100 <bailsman> No, because the "pure part" of the code should not write anywhere
2024-11-12 20:17:18 +0100 <EvanR> mutable array it is
2024-11-12 20:17:08 +0100 <bailsman> Every iteration of the loop, every element is going to get updated again. I want to keep modifying them over and over (in place)
2024-11-12 20:16:50 +0100 <EvanR> but not the other way around
2024-11-12 20:16:47 +0100 <EvanR> "for free"
2024-11-12 20:16:39 +0100 <EvanR> the normal intuitive way sounds like you just want a mutable array. There is a thing where you can export a mutable array that you made as a "pure" immutable array from an ST action