Author Topic: Restricting unbalanced games  (Read 499 times)

Offline cen

  • Eurobattle.net Admin
  • WickedSick Member
  • *
  • Topic Author
  • Posts: 2002
  • Country: si
  • Karma: +250/-50
  • Lok'tar Ogar
  • Awards Lagabuse Legend LA High Staff [EPIC] MadBalls Tournament Winner [RARE] MVP Member [LEGENDARY]
    • View Profile
    • EuroBattle.net
    • Awards
Restricting unbalanced games
« on: May 12, 2021, 23:24 »
We are slowly rolling out a new feature that will block the game start if the teams are way out of balance.

There are two different limits currently implemented and we will decide which one to use depending on game monitoring and feedback.

1. PSR Win % limiter
When you type !balance, the command outputs the Win chance % for each team. If the difference is too big the game will not start until host balances the game (auto balance or manually). This chance is calculated purely from weighted PSR.

Proposed limit: 20%
This feature is currently disabled.

Possible negatives:
- PSR can be weird sometimes and not representing a balanced game

2. Win ratio (WR)
We calculate win ratio for each player (W/L of 6/6 means your ratio is 50%).
Then we calculate average WR per team.
Similar to the first option, if team WR difference is too big the game will not start.

Proposed limit: 22%
This feature is currently enabled.

The idea is to check who wins a lot and who does not, then average it out across teams.

Posible negatives:
- !balance currently uses PSR to shuffle the slots, it might not actually produce a state that is within limits and it can require manual balance. I will probably have to rewrite the !balance formula to use WR when this setting is turned on so manual balance is never needed after autobalance.
- new players and fresh accounts have very skewed WR. Thus, below a certain number of games we assign a not so good WR to these players instead of their actual. This can skew the result for multi accounts.


Command info expansion:
!balance
[GAME: eee] [Local]: Sentinel avg. PSR: 1535 (100% to win, avg WR=50%), Scourge avg. PSR: 0 (0% to win, avg WR=0%)

!rall
[GAME: eee] [Local]: cen (PSR=1535, WR=50%)


Bots will be replaced in gradual rollout once we confirm everything works as expected.


Best regards, cen
« Last Edit: May 16, 2021, 22:09 by iErnesto94 »

Offline cen

  • Eurobattle.net Admin
  • WickedSick Member
  • *
  • Topic Author
  • Posts: 2002
  • Country: si
  • Karma: +250/-50
  • Lok'tar Ogar
  • Awards Lagabuse Legend LA High Staff [EPIC] MadBalls Tournament Winner [RARE] MVP Member [LEGENDARY]
    • View Profile
    • EuroBattle.net
    • Awards
Re: Restricting unbalanced games
« Reply #1 on: May 13, 2021, 09:14 »
TODO: add WR info to !rs

Offline cen

  • Eurobattle.net Admin
  • WickedSick Member
  • *
  • Topic Author
  • Posts: 2002
  • Country: si
  • Karma: +250/-50
  • Lok'tar Ogar
  • Awards Lagabuse Legend LA High Staff [EPIC] MadBalls Tournament Winner [RARE] MVP Member [LEGENDARY]
    • View Profile
    • EuroBattle.net
    • Awards
Re: Restricting unbalanced games
« Reply #2 on: May 13, 2021, 20:55 »
Bot crash probably fixed.

edit: not yet..
« Last Edit: May 14, 2021, 15:47 by cen »

Offline cen

  • Eurobattle.net Admin
  • WickedSick Member
  • *
  • Topic Author
  • Posts: 2002
  • Country: si
  • Karma: +250/-50
  • Lok'tar Ogar
  • Awards Lagabuse Legend LA High Staff [EPIC] MadBalls Tournament Winner [RARE] MVP Member [LEGENDARY]
    • View Profile
    • EuroBattle.net
    • Awards
Re: Restricting unbalanced games
« Reply #3 on: May 16, 2021, 19:23 »
All bots replaced, PSR win chance max 22% difference.

Offline cen

  • Eurobattle.net Admin
  • WickedSick Member
  • *
  • Topic Author
  • Posts: 2002
  • Country: si
  • Karma: +250/-50
  • Lok'tar Ogar
  • Awards Lagabuse Legend LA High Staff [EPIC] MadBalls Tournament Winner [RARE] MVP Member [LEGENDARY]
    • View Profile
    • EuroBattle.net
    • Awards
Re: Restricting unbalanced games
« Reply #4 on: May 24, 2021, 18:16 »
After running some tests on the balance and gain formula, it is determined that the +1/-1 change which was done a few years ago, while done with good intensions, it breaks the formula on the high end. It also encouraged more imbalanced games, since before the change, these players would get +0 in the same lobby.

At the same time, it is also a problem right now that some of the high PSR players are completely blocked from starting a game unless they find a strong on average opponent team or an equal player in the same lobby. Even with in-theory average to strong lobbies, the chances with players in 1800+ territory are greatly overblown.

Therefore, changes are:

1. +1/-1 will only be enabled if the game is balanced. If game is not balanced, +0 is possible again.
2. Balance (green) zone set to 24% (38-62 max).
3. Game start is blocked in extreme imbalance. Current limit is (20-80).
4. Ladder reset July 1st. This is necessary because PSR is elevated and waiting until the end of the year is a long time for changes to actually be visible in practice.


In theory these changes will:
- lower the top end of PSR because +1/-1 will be harder to achieve but still possible
- win % chance gaps will be lower

Changes will be rolled over in the next hours/days.

I am semi-confident this will work for the long term, even if some numbers might need to be tweaked.
« Last Edit: May 24, 2021, 18:19 by cen »