#robotics Logs

Oct 20 2017

12:55 AM anonnumberanon: yeah i use notebooks
12:58 AM anonnumberanon: so now gonna work on trying to write a solution for that 3rd challenge I had
12:58 AM anonnumberanon: given array of length N, put the numbers of the array in 3 different sums, at the end all sums must be equal to each other
12:59 AM anonnumberanon: you cannot use 1 number more than once
12:59 AM rue_mohr: oh, the board length problem
12:59 AM rue_mohr: (given this list of stupid peices, find the best fit combinations for boards of this length)
01:00 AM anonnumberanon: some sums can be empty and thus sum up to if for example you put 5 and -5 in one of the sum which sums up to 0, then another sum that is empty would be okay, as both sums would be equal, 0 doesn't matter
01:00 AM anonnumberanon: could be all sums are worth 7 or whatever
01:01 AM rue_mohr: how much time is ascceptable to spend searching tho?
01:01 AM anonnumberanon: i think they want you to focus on N being at most 18, and usually they want 10 milliseconds execution time?
01:04 AM rue_mohr: no, no N^3
01:04 AM theBear: rue_mohr, depends how angry and stiff in the shoulders yer willing to make yerself that day <grin> it's one of those double or nothing situations i find increasingly as time passes... if you don't remember to stop before things get a bit outta hand, you feel increasingly that you're wasting time that you already spent if you don't get a result :)
01:04 AM rue_mohr: so, no N^3
01:05 AM rue_mohr: theBear, but I mean like, are we talking start the program and go get a coffee, or finishes before the webpage I just clicked on loads
01:05 AM rue_mohr: or beofre I get impatient with it (about 470ms)
01:06 AM anonnumberanon: for this specific problem i don't know
01:06 AM rue_mohr: so is the input carefull controlled?\
01:07 AM anonnumberanon: with N = 18 maybe it could take a few seconds
01:07 AM anonnumberanon: non-optimized
01:07 AM anonnumberanon: and very fast if using dynamic programming maybe, with lots of optimizations
01:07 AM anonnumberanon: like when i did something that would take 64 years in 4 seconds using dynamic programming.
01:08 AM anonnumberanon: that was sweet
01:08 AM rue_mohr: I dont like the erm dynamic programming, its not a good fit for whats just a reasonable optimization technique
01:08 AM anonnumberanon: what would you call it?
01:08 AM rue_mohr: dynamic programming should be softwre that literally rewrites itself, more so than self modifying code
01:10 AM anonnumberanon: do you also have a problem with "dynamic memory allocation"?
01:10 AM rue_mohr: I'd call it persistent historic computation caching optimization
01:10 AM rue_mohr: PHCCO
01:12 AM rue_mohr: even a subroutine stack could be reffered to as dynamic programming and it would be mroe accurate
01:13 AM rue_mohr: (one routine pushes a sequence of calls on a stack, events can purge the stack and cache a new set of routines)
01:14 AM rue_mohr: I used it programming kids games
01:14 AM rue_mohr: when you know things like "there are going to be 5 questions, and then a payoff"
01:14 AM rue_mohr: but after two questions they restart the set instead
01:15 AM rue_mohr: I have yet to implement that in C
01:16 AM anonnumberanon: c++ is fun
01:16 AM rue_mohr: ITS A STUPID USELESS LANGUAGE
01:16 AM rue_mohr: :)
01:17 AM anonnumberanon: im writing things only in that lately
01:17 AM anonnumberanon: doing all the coding challenges i can
01:17 AM rue_mohr: so you said
01:17 AM anonnumberanon: even after that terrible defeat I experience I will continue and next time EXPECT ME
01:18 AM rue_mohr: ...
01:18 AM rue_mohr: why dont you take on some of my stuff, I'm not enough people anyhow
01:18 AM rue_mohr: you know what a state machine is, right?
01:19 AM anonnumberanon: no I can't
01:19 AM anonnumberanon: it has to be dumb job interview questions
01:19 AM theBear: rue_mohr, lol, i was just saying that, only more verbosely (and unusually for you vs me) and a little less abusive-ly <grin>
01:20 AM rue_mohr: :)
01:20 AM rue_mohr: theBear, would you like a job progr.... no I already asked you this
01:20 AM rue_mohr: hmm, where I gonna find someone to do some side-php programming?
01:21 AM theBear: rue_mohr, i think a lot of these new comers just can't see things the same way we do, cos they never been able to peg a cpu and run outta time to get their mathing done, or able to ya know, fill a disk with code that only took them hours to write etc etc .. not to mention that we learned all our basic algorithmic kinda skills in an age not just before multitasking, but before anyone had been stupid enough to think up this whole object orientater'd
01:21 AM theBear: nonsense :)
01:21 AM anonnumberanon: you can pay an east europe guy to do it for 1 euro maybe
01:21 AM theBear: if he ever comes to visit or remebmers to give me his "new" fone number, i got yer guy, just that errm he doesn';t
01:22 AM rue_mohr: I know somone who needs a php coder
01:22 AM rue_mohr: for money
01:22 AM rue_mohr: (no scubysnacks)
01:23 AM rue_mohr: WHEN did I get old?!?
01:24 AM anonnumberanon: you regularly get old, what's new?
01:24 AM theBear: heh, if i was a smartass (you know, one of them ungrateful whipper-snapper types<grin>) i'd probly say something like XX years before i did <cheeky grin>
01:24 AM theBear: maybe you do ! i do it in fits and bursts
01:25 AM theBear: or maybe that's just how i do things that make me aware of it, you know, personal grooming, looking in the mirror, that kinda stuff... hard to tell from where i standing <winK>
01:25 AM rue_mohr: 1262277000 second mark felt a lot older
01:27 AM rue_mohr: sure be nice if rifraf kept in touch, I know he's up to soemthing interesting somewhere
01:27 AM rue_mohr: arg, gnight
01:28 AM theBear: mmm, gotta be tricky living in butt-f&*(k nowhere AND building some of the finest (and certainly many-of) cnc this+that's in the country, least far as i can tell
01:39 AM anonnumberanon: theBear, how is your health
01:39 AM anonnumberanon: feeling better from your axe accident?
01:41 AM Jak_o_Shadows: headlight
01:41 AM Jak_o_Shadows: now i just need to decide if i want to retain torch capability
01:45 AM Jak_o_Shadows: I wonder waht the current is...
01:47 AM Jak_o_Shadows: <500mA at 12V
01:47 AM Jak_o_Shadows: Starting to wonder about using a boost converter
02:53 AM Jak_o_Shadows: hmm. Can I fit a stm32, boost converter, mosfet (to-200?) and a bluetooth module onto a 5x7 bit of perboard
02:54 AM Jak_o_Shadows: wihout having bits run vertically
02:54 AM Jak_o_Shadows: oh, and include a couple of caps as well
03:04 AM Jak_o_Shadows: hmm, if i put a voltage regulator in as well, it could run off battery
03:08 AM Jak_o_Shadows: hmm, scratch running it off a lantern batteyr. space is just too tight
04:34 AM Jak_o_Shadows: Could totally fit 3 li-ions in though
05:17 AM dfgsdfg: robots will take our jobs
05:31 AM theBear: i got no problem with that ;-P
05:32 AM z64555: only if we give it to them
05:35 AM theBear: anonnumberanon, yeah y'know, nothing worth complaining about ;-) seems the evil f&*(er is actually going right thru a lengthy trial (which doesn't delay anything or suggest there's any chance of it helping his future, EXCEPT) which means i don't get back my less-than-week-old shiny new shoes and one of my more respectable (AND liked by myself) for at least a few more months, which makes me sad... but only a little bit, so ya know, don't bother
05:35 AM theBear: worrying about it <wink>
05:37 AM anonnumberanon: theBear, i feel your pain it's always a tragedy when shoes get damaged, they're you're only interface with the ground
05:37 AM theBear: strangely enough still haven't got another upstairs neighbor, or a new caretaker/super for the whole place, which ain't so bad, but i had gotten used to having someone live on the other side of my ceiling it seems... realestate prices here, specially renatls (which upstairs isn't, but most here are,) are going thru the FLOOR, prices lower than i've ever paid myself and i been renting here and there for closer to 20 years than 15, and all over the
05:37 AM theBear: country and usually at the cheapest end of town...
05:38 AM anonnumberanon: makes me wish people around me got killed more often yeah
05:40 AM anonnumberanon: meh i don't pay much for rent i just have this setup where the landlady lives in the kitchen and makes really loud noises with her mouth most of the time when I'm trying to go to bed
05:42 AM theBear: heh, strangely enough if anything this has had SLIGHTLY the opposite effect on me, noting that i always had a problem with most of the general public.... oh, you mean the rents, heh, that's not just here, that's all across the state... apparently our decade of ruling the flyin/flyout mining job world is over, and not recovering in a hurry
05:59 AM * z64555 looks at other splines on wikipedia to see if they might be useful
06:02 AM z64555: trying to find one that'll trace the position of an object with initial and ending kinematics
06:10 AM z64555: hm, here's something that uses dual quaternions.
06:11 AM z64555: https://en.wikipedia.org/wiki/Rational_motion
06:38 AM anonnumberanon: what's the goal of your research z64555 ?
06:43 AM z64555: find something that I can use to predict motion of a bot
06:45 AM z64555: in like, a free-flight setting
06:47 AM z64555: I've already looked at quadratic and cubic beziers, both of which are not particularly useful
06:47 AM anonnumberanon: wow
06:47 AM z64555: well, quadratic beziers are great for simple trajectories (bullet physics)
06:48 AM anonnumberanon: define motion of a bot though
06:48 AM z64555: cubic beziers *would* be good for curves that require an approach vector to the end point, but they require an initial acceleration into the curve
06:49 AM z64555: the position of a bot in space
06:49 AM z64555: The motion of that bot as it goes through a curve from point A to point B
06:49 AM anonnumberanon: what type of bot
06:50 AM theBear: hehe, y'all said bot-bot
06:50 AM anonnumberanon: i've progressed on that buckets programming challenge
06:50 AM anonnumberanon: actually i think i have a full brute force solution in my head
06:50 AM anonnumberanon: which is already half the work
06:50 AM z64555: its free-flight, so it could be like a quadrotor, helicopter, airplane, spacecraft
06:51 AM z64555: or submarine in still water
06:51 AM anonnumberanon: take the array, find all of its "subsequences", for each subsequence, the characters not in it, use them to find the next subsequences, do it 3 times if you have 3 buckets
06:52 AM anonnumberanon: well 3 levels of recursion i mean
06:53 AM anonnumberanon: at the end of each 3rd level, sum the subsequence elements together, compare them to the other 2 levels for equality, if found return
06:53 AM anonnumberanon: dont know how i could make it dynamic though
06:53 AM anonnumberanon: not sure if that would be similar to the "partition problem"
06:55 AM z64555: I'm not gonna be much help on that one, I'm afraid
06:56 AM z64555: also, my car has a doctor's appointment today
06:56 AM z64555 is now known as z64[afk]
06:56 AM Jak_o_Shadows: theBear, oh boy, australia's economics and etc, etc, etc
06:56 AM z64[afk]: catch up with you later, maybe
06:56 AM anonnumberanon: good luck on car
06:58 AM theBear: Jak_o_Shadows, erm, if you say so pfft... one of the advantages of being unfit to work i guess, unless steak and fancy beer/liquor somehow magically become 1/10th the price they usually are, nothing financial is gonner catch my attemntopm
06:59 AM Jak_o_Shadows: hmm. I think I might mean "australia's politics, etc, etc"
06:59 AM Jak_o_Shadows: but hey, we're finally getting a space agency! super exciting
07:08 AM theBear: we are ? and on the politics note, i'm aware that it exists, but i sure have gotten good at COMPLETELY ignoring and avoiding any knowledge of it over the years... i can honestly say i have no idea who runs the country i live in, from the local level right up to the highest levels of 'power' (i spose i know we got a queen in some other country far away, but not only is she a harmless nice old lady of a figurehead, her husband is effing hilarious ! so
07:08 AM theBear: ya know, i can't in good conscience be down on her whole deal)
07:09 AM Jak_o_Shadows: We are! Hopefully we join the ESA, and keep stuff. It'll be good.
07:10 AM Jak_o_Shadows: Yeah, I don't understand why you would bother disliking the queen.
07:10 AM Jak_o_Shadows: Sounds like to much effort
07:13 AM theBear: if yer never paid much attention to the old feller, look up a couple speeches or a handful of quotes her old feller said over the years, more often than not in the most inappropriate of places and situations, he's AMAZING !
07:22 AM Jak_o_Shadows: yeah.
09:47 AM edmoore: Jak_o_Shadows: i'm not sure that joining esa is something to especially look forward to
04:23 PM z64[afk]: car fixed
04:23 PM z64[afk] is now known as z64555
11:27 PM * z64555 tries to learn dual quaternions