Changed to smaller float

src/services/elo.go

@@ -19,13 +19,13 @@ import (
 )
 
 var eloCfg = struct {
-	Mu0              float64
-	Scale            float64 // KNew applies to players during burn-in (first BurnInGames matches).
-	KNew             float64
-	KStd             float64
+	Mu0              float32
+	Scale            float32 // KNew applies to players during burn-in (first BurnInGames matches).
+	KNew             float32
+	KStd             float32
 	BurnInGames      int
-	RatingFloor      float64
-	MaxPerMatchDelta float64
+	RatingFloor      float32
+	MaxPerMatchDelta float32
 	MaxGoals         int
 }{
 	Mu0:              1500,
@@ -41,16 +41,16 @@ var eloCfg = struct {
 type Team struct {
 	Players       []*repository.GameUser
 	Score         int
-	AverageRating float64
+	AverageRating float32
 }
 
 func NewTeam(players []*repository.GameUser, score int) *Team {
-	var t1s float64 = 0
+	var t1s float32 = 0
 	for _, player := range players {
-		t1s += float64(player.User.Elo)
+		t1s += float32(player.User.Elo)
 
 	}
-	t1a := t1s / float64(len(players))
+	t1a := t1s / float32(len(players))
 
 	return &Team{Players: players, Score: score, AverageRating: t1a}
 }
@@ -80,9 +80,9 @@ func GetNewElo(t1, t2 *Team) error {
 	return nil
 }
 
-func CalculateRating(rA, rB float64, goalsA, goalsB, gamesA int) (newrA float64, err error) {
+func CalculateRating(rA, rB float32, goalsA, goalsB, gamesA int) (newrA float32, err error) {
 	// Observed score (no draws)
-	var sA float64
+	var sA float32
 	if goalsA > goalsB {
 		sA = 1.0
 	} else {
@@ -105,7 +105,7 @@ func CalculateRating(rA, rB float64, goalsA, goalsB, gamesA int) (newrA float64,
 	eA := expected(eloCfg.Scale, rA, rB)
 	mov := movFactor(rA, rB, diff)
 
-	var Keff float64
+	var Keff float32
 	if gamesA <= eloCfg.BurnInGames {
 		Keff = eloCfg.KNew
 	} else {
@@ -124,13 +124,15 @@ func CalculateRating(rA, rB float64, goalsA, goalsB, gamesA int) (newrA float64,
 	return rA + delta, nil
 }
 
-// expected returns the win probability for player A against B
-func expected(scale, rA, rB float64) float64 {
-	return 1.0 / (1.0 + math.Pow(10.0, -(rA-rB)/scale))
+func expected(scale, rA, rB float32) float32 {
+	return float32(
+		1.0 / (1.0 + math.Pow(10.0, float64(-(rA-rB)/scale))),
+	)
 }
 
-// movFactor returns a bounded margin-of-victory multiplier.
-func movFactor(rA, rB float64, diff int) float64 {
+func movFactor(rA, rB float32, diff int) float32 {
 	fd := float64(diff)
-	return math.Log(fd+1.0) * 2.2 / (math.Abs(rA-rB)*0.001 + 2.2)
+	return float32(
+		math.Log(fd+1.0) * 2.2 / (math.Abs(float64(rA-rB))*0.001 + 2.2),
+	)
 }