Picking out random bits

ID:1372951
 
Sep 8 2013, 7:16 pm
(See the best response by Ss4toby.)

Problem description:

Hey guys. I've been working on a system which manages resources on the map; when it's started it picks out available turfs from a specific area and spawns resources there.

Problem is, what I've written to do that isn't very good. For some reason I can't think of a proper way to efficiently pick a random amount of things out of a list. Anyone have any ideas? This is what I'm trying to do.

        populate()
            var counter = Tin + Copper + Iron + Silver + Gold
            var list/available = list()
            var turf/cturf
            var runcount = 0
            while(runcount < Area.contents.len)
                cturf = pick(Area.contents)
                if(!cturf.PMade)
                    if(!available.Find(cturf)) // we don't want duplicates
                        available += cturf
                        
                if(available.len >= counter)
                    break
                runcount++
            oresOn(available)


Sep 8 2013, 7:30 pm
Here's a quick rewrite because I don't understand the question:
...
var stuff[] = Area.contents.Copy()
while(stuff.len && available.len < counter && runcount++ < stuff.len)
    cturf = pick(stuff)
    stuff -= cturf
    if(!cturf.PMade)
        available += cturf
oresOn(available)
Sep 8 2013, 8:04 pm
In response to Kaiochao
That's definitely a step in the right direction, although I don't think it was quite the solution. I adapted it into this:

        populate()
            var counter = Tin + Copper + Iron + Silver + Gold
            var list/available = list()
            var list/looping = Area.contents.Copy()
            var turf/cturf
            var maxcount = looping.len
            var runcount = 0
            while(looping.len && (available.len < counter) && (runcount++ < maxcount))
                cturf = pick(looping)
                looping -= cturf
                if(!cturf.PMade)
                    available += cturf
            oresOn(available)


Since we have to stop the loop at some point, my goal with runcount is to only run the loop for however many turfs were in the area.

If the area contained 500 turfs, then it doesn't make much sense to run the loop more than 500 times.

The way you've done it makes it so that it's possible to check for duplicates and limit it via the amount of times it was ran, which is cool.

The game still locks up when I use this though..

Edit: The check for looping.len should do that on it's own, hm. I'll make some changes.

        populate()
            var counter = Tin + Copper + Iron + Silver + Gold
            var list/available = list()
            var list/looping = Area.contents.Copy()
            var turf/cturf
            while(looping.len && (available.len < counter))
                cturf = pick(looping)
                looping -= cturf
                if(!cturf.PMade)
                    available += cturf
            oresOn(available)
Sep 8 2013, 8:20 pm
To eliminate lock-up, use set background = 1

        populate()
            var counter = Tin + Copper + Iron + Silver + Gold
            var list/available = list()
            var list/looping = Area.contents.Copy()
            var turf/cturf
            while(looping.len && (available.len < counter))
                set background = 1   
                cturf = pick(looping)
                looping -= cturf
                if(!cturf.PMade)
                    available += cturf
            oresOn(available)


Honestly though, the script doesn't look like it should be locking up. Could be whatever is in oresOn()?

Also, a side note. Although I find the method of removing from the list more appealing, a good way to avoid adding dupes to a list is list |= value
Sep 8 2013, 8:24 pm
In response to Ss4toby
Yeah, I tested that. When I run this, oresOn() isn't included. Just the loop locks up. For some reason the loop isn't ending.
Sep 8 2013, 8:28 pm
Any runtime errors? Based on what I see, the loop shouldn't be stuck in inf.
Sep 8 2013, 8:38 pm
Best response
Also! Forgot to mention this. Area.contents doesn't just return turfs, it returns everything in the area. So, you may want to utilize a for(var/turf/T in Area.contents) instead of a loop, and then just break. Of course, this would require re-designing the entire system >.<..

I suppose something like this might help, but is not idea:
        populate()
            var counter = Tin + Copper + Iron + Silver + Gold
            var list/available = list()
            var list/looping
            var turf/cturf
            for(var/turf/t in Area.contents)
                set background = 1
                looping+=t
            while(looping.len && (available.len < counter))
                set background = 1   
                cturf = pick(looping)
                looping -= cturf
                if(!cturf.PMade)
                    available += cturf
            oresOn(available)


Honestly, the best method I can think of is to forget using area.contents all together and use block..

        populate()
            var counter = Tin + Copper + Iron + Silver + Gold
            var list/available = list()
            var list/looping=block(locate(1,1,1),locate(world.maxx,world.maxy,1)
            var turf/cturf
            while(looping.len && (available.len < counter))
                set background = 1   
                cturf = pick(looping)
                looping -= cturf
                if(!cturf.PMade)
                    available += cturf
            oresOn(available)


The given example will return all turfs on the entire z-level.
Sep 8 2013, 8:47 pm
Aha, that was the problem. I wasn't aware that areas contained turfs AND the turfs' contents. Changing it to this works out perfectly.

The latter example MAY be better, I'm not sure, but for my purposes no. This proc is designed under a special manager datum for an area's resources. Not all my areas contain a square block of turfs, so it has to be area specific :)

This is resolved.
Thanks both Kaiochao and Ss4toby