Upgrade client version
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I've been thinking of upgrading the accepted client version. What are your thoughts on the matter? Have any of you tested extensively with the latest releases locally? Are there any changes in scores (or any changes that might affect scores) that we should do more extensive testing of first?
Finally 126.96.36.199 released, with RoboRumble battle duplicating fix, and with shorter participants list check period from 188.8.131.52 as well. It’s time to do a test and discuss to upgrade.
Question, what kind of tests should be done in local? Should we run a literumble locally and see whether it yields the same score as the main rumble? (which gives the best result but takes monthes). Or just using roborunner with a few robots (both 1v1 and melee certainly), and see their score is unaffected.
Just roborunner and a few bots should be fine. At some point it would be good to reset the meleerumble as well, since old bots get biased downwards by excessive battles against new (good) bots.
I've been always thinking about the pairing systems of meleerumble.
Once every combination of 10 bots had a run, the score is unbiased, which takes N = n! / (10! * (n - 10)!) ≈ 10^19 battles in current settings (n is the total of participants).
However we should get approximate score with feasible battles via monte carlo method. In current settings, ~10000 battles already gives a somewhat stable score (for the new participant).
Let each bot gets m battles, randomly selected from all (N / n) 10-bot combinations containing that bot, then the probability of meeting another specific bot in a battle is (N / n / (n - 1)) / (N / n) = 1 / (n - 1).
Assume that when a new bot is released, every battle contains that bot, then the probability of meeting that bot is 1 instead of 1 / (n - 1), which is highly biased.
To fix this, we have two options — mutate our current pairing systems to get unbiased score online, or to reset the entire meleerumble periodically.
Since the score of new bots are unbiased, all we need to do for an unbiased score is to ignore (n - 2) / (n - 1) biased battles randomly when calculating the score of an old bot. However this approach takes much more battles.
A more practical way is is, when bot A is added, for each battle, select another bot B randomly, and run melee battles containing those two bots as usual. A battle containing A, B and other 8 bots should yield 45 pairings, but only those matching (A, *) or (B, *) is taken into account. This produces 17 parings.
This scheme does not affect the pairings of the new bot itself at all, which is already unbiased; And for an old bot, the probability of being chosen as B is 1 / (n - 1), therefore the probability of a battle with A present being taken into account for old bots is 1 / (n - 1), the same as the unbiased one.
Your second approach seems good, it will need patches on the client side so that if a priority pairing needs to happen it only uploads the battles which contain one of the priority bots. This filter will work fine for the 1v1 rumble as well.
Why don't we wait to update the client until this can be fixed too?
The only reason for upgrading earlier is that those two bugs are very annoying when running rumble client 7/24.
And it generally takes monthes for fnl to release a new version in normal cycle ;(
Anyway, since those two fixes are unrelated to robocode engine, one should expect no performance difference if we cherry pick the fix back to 184.108.40.206.
Maybe we could release a special version of 220.127.116.11 for those running rumble 7/24, before the melee pairing fix is released.
Or, we may just ask fnl whether he could please release 18.104.22.168 soon after the meleerumble patch is applied.
I patched robocode 22.214.171.124's roborumble by cherry-picking roborumble client fixes from 126.96.36.199 and 188.8.131.52
The patched roborumble.jar can be downloaded from:
This should check participants list more often preventing retired bots from being battled and submitted nullifying smart battles. And on unstable network it won't upload 80000 duplicate battles for a single pairing any more. (See pulsar.PulsarNano 0.2.4 and ad.last.Bottom 1.0)
I suspect we should separate roborumble version and robocode version (since they are weakly dependent) and get roborumble bug fixes quicker than robocode, since roborumble bugs are generally more serious, and roborumble fixes has nothing to do with the rest of robocode users.
Currently fixes in roborumble takes almost a year to be actually deployed.
I've enabled 184.108.40.206 for uploads. Let's try it for a while and see how it goes. If we notice anything strange, well, the rumble probably needs a wipe some time soon anyway, and definitely melee.
I'll upgrade all my clients later and upload the same bot of mine with different version number to see the impact on score...
The melee part is already discussed, but why the 1v1 rumble needs a wipe as well? And how long it should take to reload the rumble? Or should we run the current rumble as a backup in parallel until the reload completes? (so that new players can still submit their bots)
Hopefully we don't need to wipe 1v1 rumble. I am more just concerned with bad configurations, running with Java10 etc that have accumulated.
Have you managed to make a patch for the melee priority battles?
The rumble clients load version number dynamically, maybe we should tweak this to append Java version after version number as well to prevent running and uploading with Java 10 incidentally.
And since we have rolling average, the accumulated effect of bad configurations should be fixed automatically (after a lot of battles).
A patch for melee priority battle is harder than I thought, as the data structure (currently, very bad, string) needs a redesign for the extra 1 bit of information. And almost every line of code needs a rewrite as it depends on the implementation details of the (not extensible) data structure.
Done! After some refactoring, the rumble client should upload only pairings containing the prioritized bot, or containing the predetermined random bot when running prioritized battles.
The only flaw is that when the rumble server returns prioritized pairings, etc. A and B, if B is not evenly distributed, then B will get biased battles (meet more A). Is literumble using this feature currently? How not evenly distributed is bot B returned in this case?
Bot B is randomly selected from missing pairs, or if pairings are complete then randomly selected, with weighting biased towards lower number of battle pairs. It should be ok (and regardless, much much better than the current situation)