func calculateNewRating(winnerId, loserId int64, winnerRating, winnerStdDev, loserRating, loserStdDev float64) (winnerNewRating, winnerNewStdDev, loserNewRating, loserNewStdDev, quality float64) {
team1 := skills.NewTeam()
team2 := skills.NewTeam()
team1.AddPlayer(winnerId, skills.NewRating(winnerRating, winnerStdDev))
team2.AddPlayer(loserId, skills.NewRating(loserRating, loserStdDev))
teams := []skills.Team{team1, team2}
var calc trueskill.TwoPlayerCalc
ratings := calc.CalcNewRatings(skills.DefaultGameInfo, teams, 1, 2)
quality = calc.CalcMatchQual(skills.DefaultGameInfo, teams)
return ratings[winnerId].Mean(), ratings[winnerId].Stddev(), ratings[loserId].Mean(), ratings[loserId].Stddev(), quality
}
func RateGames(players []int64, games []Result) (Rankings, error) {
// TODO(dm): this function is messy because the API we are depending on
// (GoSkills) is pretty weird. Could be cleaned up by just moving the
// calculation logic into our own impl
if err := checkGameParticipantsArePlayers(players, games); err != nil {
return nil, err
}
ratings := DefaultRatings(players)
for _, r := range games {
whiteTeam := skills.NewTeam()
whiteTeam.AddPlayer(r.WhiteID, rating2srating(ratings[r.WhiteID]))
blackTeam := skills.NewTeam()
blackTeam.AddPlayer(r.BlackID, rating2srating(ratings[r.BlackID]))
var twoPlayerCalc trueskill.TwoPlayerCalc
ranks, err := outcomeToRanks(r.Outcome)
if err != nil {
return nil, err
}
newSkills := twoPlayerCalc.CalcNewRatings(gameInfo, []skills.Team{whiteTeam, blackTeam}, ranks...)
ratings[r.WhiteID] = srating2rating(newSkills[r.WhiteID])
ratings[r.BlackID] = srating2rating(newSkills[r.BlackID])
}
ranks := make(Rankings, 0)
for id, rating := range ratings {
ranks = append(ranks, Ranking{PlayerID: id, Rating: rating, Rank: -1})
}
sort.Sort(ranks)
var prevRating Rating
for i, _ := range ranks {
if prevRating == ranks[i].Rating {
ranks[i].Rank = ranks[i-1].Rank
} else {
ranks[i].Rank = i + 1
}
prevRating = ranks[i].Rating
}
return ranks, nil
}