
BGonline.org Forums
VRR  Challenge
Posted By: Maik Stiebler
Date: Saturday, 31 January 2015, at 8:10 a.m.
In Response To: VRR  Challenge (Rick Janowski)
I don't think there is an article and can't remember a posting, but I can make one.
This is how you get the variance reduced rating change:
 Remind yourself of how the FIBS formula works.
 As per the FIBS formula, "Let D = abs(r1r2) [rating difference]. Let P_upset = 1/(10^(D*sqrt(n)/2000)+1) [probability that underdog wins]"
 Now let Ru equal the luckadjusted result of the underdog as given by the bots. For GnuBG, you will have to add 50% to the output number, as it is normalized to live in a typical range of [50%, 50%] as opposed to the typical range of [0,100%] that XG uses.
 Let P = Ru  P_upset.
 For each player, let K = max ( 1 , experience/100+5 )
 The rating change for the underdog is 4*K*sqrt(n)*P, for the favorite it is 4*K*sqrt(n)*P
 I already mentioned that you can increase the unramped game value 4*sqrt(n) when using VR. Maybe you will find that after increasing it enough, no ramping will be needed anymore.

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