Fix sometimes ammo schemes not being saved after changing before an ammo scheme got deleted in session
This was because the bool isDeleting is not initialized, so its initial value is unpredictable.
Which means there's chance it starts with true, confusing the frontend.
{-
Glicko2, as described in http://www.glicko.net/glicko/glicko2.pdf
-}
module OfficialServer.Glicko2 where
data RatingData = RatingData {
ratingValue
, rD
, volatility :: Double
}
data GameData = GameData {
opponentRating :: RatingData,
gameScore :: Double
}
τ, ε :: Double
τ = 0.2
ε = 0.000001
g_φ :: Double -> Double
g_φ φ = 1 / sqrt (1 + 3 * φ^2 / pi^2)
calcE :: RatingData -> GameData -> (Double, Double, Double)
calcE oldRating (GameData oppRating s) = (
1 / (1 + exp (g_φᵢ * (μᵢ - μ)))
, g_φᵢ
, s
)
where
μ = (ratingValue oldRating - 1500) / 173.7178
φ = rD oldRating / 173.7178
μᵢ = (ratingValue oppRating - 1500) / 173.7178
φᵢ = rD oppRating / 173.7178
g_φᵢ = g_φ φᵢ
calcNewRating :: RatingData -> [GameData] -> (Int, RatingData)
calcNewRating oldRating [] = (0, RatingData (ratingValue oldRating) (173.7178 * sqrt (φ ^ 2 + σ ^ 2)) σ)
where
φ = rD oldRating / 173.7178
σ = volatility oldRating
calcNewRating oldRating games = (length games, RatingData (173.7178 * μ' + 1500) (173.7178 * sqrt φ'sqr) σ')
where
_Es = map (calcE oldRating) games
υ = 1 / sum (map υ_p _Es)
υ_p (_Eᵢ, g_φᵢ, _) = g_φᵢ ^ 2 * _Eᵢ * (1 - _Eᵢ)
_Δ = υ * part1
part1 = sum (map _Δ_p _Es)
_Δ_p (_Eᵢ, g_φᵢ, sᵢ) = g_φᵢ * (sᵢ - _Eᵢ)
μ = (ratingValue oldRating - 1500) / 173.7178
φ = rD oldRating / 173.7178
σ = volatility oldRating
a = log (σ ^ 2)
f :: Double -> Double
f x = exp x * (_Δ ^ 2 - φ ^ 2 - υ - exp x) / 2 / (φ ^ 2 + υ + exp x) ^ 2 - (x - a) / τ ^ 2
_A = a
_B = if _Δ ^ 2 > φ ^ 2 + υ then log (_Δ ^ 2 - φ ^ 2 - υ) else head . dropWhile ((>) 0 . f) . map (\k -> a - k * τ) $ [1 ..]
fA = f _A
fB = f _B
σ' = (\(_A, _, _, _) -> exp (_A / 2)) . head . dropWhile (\(_A, _, _B, _) -> abs (_B - _A) > ε) $ iterate step5 (_A, fA, _B, fB)
step5 (_A, fA, _B, fB) = let _C = _A + (_A - _B) * fA / (fB - fA); fC = f _C in
if fC * fB < 0 then (_B, fB, _C, fC) else (_A, fA / 2, _C, fC)
φ'sqr = 1 / (1 / (φ ^ 2 + σ' ^ 2) + 1 / υ)
μ' = μ + φ'sqr * part1