func AssertRating(t *testing.T, expectedMean, expectedStddev float64, actual skills.Rating) {
if r := actual.Mean(); math.Abs(r-expectedMean) > errorTolerance {
t.Errorf("actual.Mean = %v, want %v\n%v", r, expectedMean, testLoc())
}
if r := actual.Stddev(); math.Abs(r-expectedStddev) > errorTolerance {
t.Errorf("actual.Stddev = %v, want %v\n%v", r, expectedStddev, testLoc())
}
}
func srating2rating(s skills.Rating) Rating {
return Rating{Mean: s.Mean(), Stddev: s.Stddev()}
}
func twoPlayerCalcNewRating(gi *skills.GameInfo, selfRating, oppRating skills.Rating, comparison int) skills.Rating {
drawMargin := drawMarginFromDrawProbability(gi.DrawProbability, gi.Beta)
c := math.Sqrt(numerics.Sqr(selfRating.Stddev()) + numerics.Sqr(oppRating.Stddev()) + 2*numerics.Sqr(gi.Beta))
winningMean := selfRating.Mean()
losingMean := oppRating.Mean()
if comparison == skills.Lose {
winningMean = oppRating.Mean()
losingMean = selfRating.Mean()
}
meanDelta := winningMean - losingMean
var v, w, rankMultiplier float64
if comparison != skills.Draw {
v = vExceedsMarginC(meanDelta, drawMargin, c)
w = wExceedsMarginC(meanDelta, drawMargin, c)
rankMultiplier = float64(comparison)
} else {
v = vWithinMarginC(meanDelta, drawMargin, c)
w = wWithinMarginC(meanDelta, drawMargin, c)
rankMultiplier = 1
}
meanMultiplier := (numerics.Sqr(selfRating.Stddev()) + numerics.Sqr(gi.DynamicsFactor)) / c
varianceWithDynamics := numerics.Sqr(selfRating.Stddev()) + numerics.Sqr(gi.DynamicsFactor)
stdDevMultiplier := varianceWithDynamics / numerics.Sqr(c)
newMean := selfRating.Mean() + (rankMultiplier * meanMultiplier * v)
newStdDev := math.Sqrt(varianceWithDynamics * (1 - w*stdDevMultiplier))
return skills.NewRating(newMean, newStdDev)
}