// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence. // See the LICENCE file in the repository root for full licence text. using System; using System.Collections.Generic; using System.Linq; using osu.Game.Rulesets.Scoring; namespace osu.Game.Screens.Ranking.Statistics { /// <summary> /// Displays the unstable rate statistic for a given play. /// </summary> public class UnstableRate : SimpleStatisticItem<double> { /// <summary> /// Creates and computes an <see cref="UnstableRate"/> statistic. /// </summary> /// <param name="hitEvents">Sequence of <see cref="HitEvent"/>s to calculate the unstable rate based on.</param> public UnstableRate(IEnumerable<HitEvent> hitEvents) : base("Unstable Rate") { var timeOffsets = hitEvents.Where(e => !(e.HitObject.HitWindows is HitWindows.EmptyHitWindows) && e.Result.IsHit()) .Select(ev => ev.TimeOffset).ToArray(); Value = 10 * standardDeviation(timeOffsets); } private static double standardDeviation(double[] timeOffsets) { if (timeOffsets.Length == 0) return double.NaN; var mean = timeOffsets.Average(); var squares = timeOffsets.Select(offset => Math.Pow(offset - mean, 2)).Sum(); return Math.Sqrt(squares / timeOffsets.Length); } protected override string DisplayValue(double value) => double.IsNaN(value) ? "(not available)" : value.ToString("N2"); } }