forked from mirrors/0ad
leper
c3ebb50711
Fix game listings. Fix non-hosts unregistering games. Patch by scythetwirler. This was SVN commit r14228.
32 lines
1.5 KiB
Python
32 lines
1.5 KiB
Python
from config import elo_sure_win_difference, elo_k_factor_constant_rating
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def get_rating_adjustment(rating, opponent_rating, games_played, opponent_games_played, result):
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"""
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Calculates the rating adjustment after a 1v1 game finishes using simplified ELO.
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Arguments:
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rating, opponent_rating - Ratings of the players before this game.
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games_played, opponent_games_played - Number of games each player has played
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before this game.
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result - 1 for the first player (rating, games_played) won, 0 for draw, or
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-1 for the second player (opponent_rating, opponent_games_played) won.
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Returns:
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The integer that should be subtracted from the loser's rating and added
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to the winner's rating to get their new ratings.
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TODO: Team games.
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"""
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opponent_volatility_influence = max(1, pow(min(games_played + 1, 50) / min(opponent_games_played + 1, 50), 0.5))
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rating_k_factor = 0.75 * pow(elo_k_factor_constant_rating / min(elo_k_factor_constant_rating, (rating + opponent_rating) / 2), 0.5)
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player_volatility = min(pow(1.1, games_played + 16), 25)
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volatility = opponent_volatility_influence * player_volatility / rating_k_factor
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difference = opponent_rating - rating
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if result == 1:
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return round(max(0, (difference + result * elo_sure_win_difference) / volatility))
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elif result == -1:
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return round(min(0, (difference + result * elo_sure_win_difference) / volatility))
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else:
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return round(difference / volatility)
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