From 16a90e946964aa25f5e6a0fbb5c6fce513e0f0a6 Mon Sep 17 00:00:00 2001 From: Russel Simmons Date: Wed, 30 Dec 2015 12:50:35 -0800 Subject: [PATCH] Fix docs regarding win % that beta corresponds to --- docs/index.rst | 2 +- trueskill/__init__.py | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/docs/index.rst b/docs/index.rst index 78cf263..11148ab 100644 --- a/docs/index.rst +++ b/docs/index.rst @@ -60,7 +60,7 @@ real skill of player is between :math:`\mu \pm 2\sigma` with 95% confidence. :: trueskill.Rating(mu=25.000, sigma=8.333) If some player's rating is higher :math:`\beta` than another player's, the -player may have about 80% of chance to beat the other player. The default value +player may have about a 76% (specifically :math:`\Phi(\frac {1}{\sqrt{2}})`) chance to beat the other player. The default value of :math:`\beta` is :math:`\frac{ 25 }{ 6 }`. Ratings will approach real skills through few times of the TrueSkill's Bayesian diff --git a/trueskill/__init__.py b/trueskill/__init__.py index b28fb9c..98a2db9 100644 --- a/trueskill/__init__.py +++ b/trueskill/__init__.py @@ -39,7 +39,7 @@ MU = 25. #: Default initial standard deviation of ratings. SIGMA = MU / 3 -#: Default distance that guarantees about 75.6% chance of winning. +#: Default distance that guarantees about 76% chance of winning. BETA = SIGMA / 2 #: Default dynamic factor. TAU = SIGMA / 100 @@ -153,7 +153,7 @@ class TrueSkill(object): :param mu: the initial mean of ratings. :param sigma: the initial standard deviation of ratings. The recommended value is a third of ``mu``. - :param beta: the distance which guarantees about 75.6% chance of winning. + :param beta: the distance which guarantees about 76% chance of winning. The recommended value is a half of ``sigma``. :param tau: the dynamic factor which restrains a fixation of rating. The recommended value is ``sigma`` per cent.