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wind23 / whole_history_rating

A Python interface incorporating a C++ implementation of the Whole History Rating algorithm
MIT License
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Order of Games Created #10

Open sx349 opened 1 month ago

sx349 commented 1 month ago

I was working on a WHR rating for Table Tennis players with ITTF match data. I noticed that when I input the match results in a rather random order, the ratings were quite unstable, e.g., there was a sudden dip in some player A's rating despite that player A did not lose (but instead he won a match) on that date. Such anomaly disappeared once I sorted the matches chronologically.

From my understanding of the WHR algorithm, it should be immune to the order of games created if the games are taking into calculation simultaneously. But I assume that the actual algorithm works on an incremental basis and thus the order of games matters. Am I understanding it correctly? If so, we may want to warn the users to create games in a proper order.

wind23 commented 1 month ago

You are right that the order in which games are created will affect the result of the algorithm. It may be a bug in the algorithm's implementation. I can check it later.