Created
January 17, 2021 11:53
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Python function to calculate changed elo rating after a chess match
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| def calc_new_elo(a,b,winner, k=20): | |
| # a = rating of a | |
| # b = rating of b | |
| # if a wins then winner = 1 | |
| # if b wins then winner = 2 | |
| # if draw then winner = 0.5 | |
| # k factor default value is 20 | |
| a_expected = 1/(1+10**((b-a)/400)) | |
| b_expected = 1/(1+10**((a-b)/400)) | |
| if winner == 1: | |
| a_scored = 1 | |
| b_scored = 0 | |
| elif winner == 2: | |
| a_scored = 0 | |
| b_scored = 1 | |
| elif winner == 0: | |
| a_scored = 0.5 | |
| b_scored = 0.5 | |
| a_new = a + k * (a_scored - a_expected) | |
| b_new = b + k * (b_scored - b_expected) | |
| print(a_new,b_new) | |
| calc_new_elo(2100, 1900, 0) | |
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