osu!standard Performance Calc: LengthBonus Removal and Star Rating Summation Change

osu.Game.Rulesets.Osu/Difficulty/OsuPerformanceCalculator.cs

@@ -88,10 +88,6 @@ private double computeAimValue(ScoreInfo score, OsuDifficultyAttributes attribut
         {
             double aimValue = Math.Pow(5.0 * Math.Max(1.0, attributes.AimDifficulty / 0.0675) - 4.0, 3.0) / 100000.0;
 
-            double lengthBonus = 0.95 + 0.4 * Math.Min(1.0, totalHits / 2000.0) +
-                                 (totalHits > 2000 ? Math.Log10(totalHits / 2000.0) * 0.5 : 0.0);
-            aimValue *= lengthBonus;
-
             // Penalize misses by assessing # of misses relative to the total # of objects. Default a 3% reduction for any # of misses.
             if (effectiveMissCount > 0)
                 aimValue *= 0.97 * Math.Pow(1 - Math.Pow(effectiveMissCount / totalHits, 0.775), effectiveMissCount);
@@ -107,7 +103,7 @@ private double computeAimValue(ScoreInfo score, OsuDifficultyAttributes attribut
             if (score.Mods.Any(h => h is OsuModRelax))
                 approachRateFactor = 0.0;
 
-            aimValue *= 1.0 + approachRateFactor * lengthBonus; // Buff for longer maps with high AR.
+            aimValue *= 1.0 + approachRateFactor;
 
             if (score.Mods.Any(m => m is OsuModBlinds))
                 aimValue *= 1.3 + (totalHits * (0.0016 / (1 + 2 * effectiveMissCount)) * Math.Pow(accuracy, 16)) * (1 - 0.003 * attributes.DrainRate * attributes.DrainRate);
@@ -141,10 +137,6 @@ private double computeSpeedValue(ScoreInfo score, OsuDifficultyAttributes attrib
 
             double speedValue = Math.Pow(5.0 * Math.Max(1.0, attributes.SpeedDifficulty / 0.0675) - 4.0, 3.0) / 100000.0;
 
-            double lengthBonus = 0.95 + 0.4 * Math.Min(1.0, totalHits / 2000.0) +
-                                 (totalHits > 2000 ? Math.Log10(totalHits / 2000.0) * 0.5 : 0.0);
-            speedValue *= lengthBonus;
-
             // Penalize misses by assessing # of misses relative to the total # of objects. Default a 3% reduction for any # of misses.
             if (effectiveMissCount > 0)
                 speedValue *= 0.97 * Math.Pow(1 - Math.Pow(effectiveMissCount / totalHits, 0.775), Math.Pow(effectiveMissCount, .875));
@@ -155,7 +147,7 @@ private double computeSpeedValue(ScoreInfo score, OsuDifficultyAttributes attrib
             if (attributes.ApproachRate > 10.33)
                 approachRateFactor = 0.3 * (attributes.ApproachRate - 10.33);
 
-            speedValue *= 1.0 + approachRateFactor * lengthBonus; // Buff for longer maps with high AR.
+            speedValue *= 1.0 + approachRateFactor;
 
             if (score.Mods.Any(m => m is OsuModBlinds))
             {

osu.Game.Rulesets.Osu/Difficulty/Skills/OsuStrainSkill.cs

@@ -34,6 +34,9 @@ public abstract class OsuStrainSkill : StrainSkill
         /// </summary>
         protected virtual double DifficultyMultiplier => DEFAULT_DIFFICULTY_MULTIPLIER;
 
+        private const double a = 10.0;
+        private const double b = 1.3675;
+
         protected OsuStrainSkill(Mod[] mods)
             : base(mods)
         {
@@ -42,7 +45,6 @@ protected OsuStrainSkill(Mod[] mods)
         public override double DifficultyValue()
         {
             double difficulty = 0;
-            double weight = 1;
 
             // Sections with 0 strain are excluded to avoid worst-case time complexity of the following sort (e.g. /b/2351871).
             // These sections will not contribute to the difficulty.
@@ -57,12 +59,19 @@ public override double DifficultyValue()
                 strains[i] *= Interpolation.Lerp(ReducedStrainBaseline, 1.0, scale);
             }
 
+            int index = 0;
+
             // Difficulty is the weighted sum of the highest strains from every section.
             // We're sorting from highest to lowest strain.
             foreach (double strain in strains.OrderByDescending(d => d))
             {
+                // Below uses harmonic sum scaling which makes the resulting summation logarithmic rather than geometric.
+                // Good for properly weighting difficulty across full map instead of using object count for LengthBonus.
+                // a and b are arbitrary constants that worked well.
+                double weight = b * ((1 + (a / (1 + index))) / (index + 1 + (a / (1 + index))));
+
                 difficulty += strain * weight;
-                weight *= DecayWeight;
+                index += 1;
             }
 
             return difficulty * DifficultyMultiplier;