Krach : Do you want it to be applied to leagues?

[Jenkar]

What is krach?
Krach is a ranking system that takes account of your opponent's score, not when you won lost/won vs him, but instead when the scores are calculated.
Xenocidius (and somewhat I) managed to make a programm that would use krach to give scores, instead of the current elo system.

The system is finalised. It imports data from google spreadsheets, and returns it after processing it through the machine.

Last BL season's results, krached. (http://xenocidius.allalla.com/pvpleague/standings.php?key=0AuLG6-uKpq33dFh2U29nLVliUjFRTUZkUmZPQ29mOEE)
Last CL season's results, krached. (http://xenocidius.allalla.com/pvpleague/standings.php?key=0AuLG6-uKpq33dHk1WXEtdXUybDZnYmZUZUM3NldSd0E)




Ki = Vi / [∑j(Nij/(Ki+Kj))]  <= this is the formula.
Explanation : Ki = krach number of player i
Vi : total victories of player i
Nij : Total number of games played by i and j.

This is recursive, as you can see.
To solve recursion, we iterate. Basicly, start with a Ki(0) = a constant for everyone (0 = iteration n°0). Then calculate the new Ki, Ki(1) for each player. Then Ki(2), Ki(3) ect.
After n iteration, you get a Ki(n). This number is a function of the number of iteration. To solve that issue (and another that i'll put just under), there is a dummy player. Everyone won and lost once vs dummy. Your real krach rating is Ki(n)/Kd(n), where Kd(n) is the dummie's krach at iteration n.
Another issue that it solves if that two sets of players aren't linked, directly or indirectly (as in, A beats C, B beats C has B&A linked, but A beats B and C beats D does not have C&D linked to A or B), the score are unrelated between the two sets.
The advantage it has over elo is that it's not time based. If A is a wonder player and you beat him while he was average (starting league), in elo it was as if you beat an average player. Not in krach (in krach, beating him at his start or at end of season is worth exactly the same).

Now, a question. What should be the average score (the score a player who won and lost a game vs everyone should have?

[Jocko]

Maybe you should include some info about how is it calculated and why it would be better than the current ELO.

[pikachufan2164]

Some basic info on KRACH, as explained by RootRanger:

This (http://www.collegehockeynews.com/info/?d=krach) explains things well.

KRACH is calculated as W:L ratio times a weighted average of your opponent's ratings. But whenever someone's rating changes, you need to recalculate the entire ratings, and then recalculate them again and again until the new calculations are about the same as the last ones.

Four main things in a rating system are important:
1.) Wins always improve the rating. Otherwise, players would always avoid battles that couldn't help them.
2.) Losses always hurt the rating. Without this, the leagues would mostly be about games played and by skill.
3.) Strength of schedule counts. If this didn't matter, people would avoid strong opponents and only want to play weaker players.
4.) Every game counts equally. This is probably the least important quality, but it is still improves a rating system because it is fair to every player.

KRACH accomplishes all four points while being able to predict odds for any game. But ELO has three of these qualities, and I guess that's good enough.

More content at the League Suggestions and Feedback thread (http://elementscommunity.org/forum/index.php/topic,7503.180.html).

I'm in favour of using KRACH, as it rewards people for wins regardless of when they've played against a person (i.e. you won't be shortchanged for winning against a strong opponent when their ELO is lower than their true ELO). As long as entries don't take insane amounts of time to enter and process, I'm all for it

[Jenkar]

Maybe you should include some info about how is it calculated and why it would be better than the current ELO.

Added math stuff.

[Jocko]

Well, now i can see why it would be better.
So, if you beat someone and then he increases his score, the amount of score you gained by beating him increases, and if his score decreases, the amount of score you gained for beating him decreases too?

[RootRanger]

Well, now i can see why it would be better.
So, if you beat someone and then he increases his score, the amount of score you gained by beating him increases, and if his score decreases, the amount of score you gained for beating him decreases too?

Yes. This creates incentive to play strong players at the beginning of the league and prevents farming weak players that just entered the league.

[AchDeToni]

Very nice, should be done this way

[Xenocidius]

This (http://xenocidius.webs.com/bl/blseason2.html) is what the finalized output will look like.

Note that it is actually faster to load than the current League standings. Also note that the ratings vary heavily with the KRACH system (getting above 2000 rating would be near-impossible with the current system).

All in all, the system is, in my opinion, better than the current one in just about every single way. It has my vote.

[Jocko]

Also note that the ratings heavily with the KRACH system (getting above 2000 rating would be near-impossible with the current system).

I can't find a sense to this sentence.
Also, wow at the gap between top 2 and the rest.

[Jenkar]

Also note that the ratings heavily with the KRACH system (getting above 2000 rating would be near-impossible with the current system).

I can't find a sense to this sentence.
Also, wow at the gap between top 2 and the rest.

I believe he meant that comparing scores to elo ones is senseless.

[Xenocidius]

Also note that the ratings heavily with the KRACH system (getting above 2000 rating would be near-impossible with the current system).

I can't find a sense to this sentence.
Also, wow at the gap between top 2 and the rest.

I accidentally a word.

[DrunkDestroyer]

It seems pretty obvious to me that this system is superior, what we really need to know is whether it would be difficult and worth the time to implement this into the leagues