From dca61d5dad27d65b372da873ac1866e93bf87db4 Mon Sep 17 00:00:00 2001
From: Andrey Akinshin <andrey.akinshin@gmail.com>
Date: Wed, 28 Aug 2013 01:05:11 +0700
Subject: [PATCH] Change Average statistic to Median

---
 BenchmarkDotNet/BenchmarkCompetition.cs |  8 ++++----
 BenchmarkDotNet/BenchmarkDotNet.csproj  |  1 +
 BenchmarkDotNet/BenchmarkRunList.cs     | 12 ++++++------
 BenchmarkDotNet/Extensions.cs           | 20 ++++++++++++++++++++
 4 files changed, 31 insertions(+), 10 deletions(-)
 create mode 100644 BenchmarkDotNet/Extensions.cs

diff --git a/BenchmarkDotNet/BenchmarkCompetition.cs b/BenchmarkDotNet/BenchmarkCompetition.cs
index 835584aa9..85db0554a 100644
--- a/BenchmarkDotNet/BenchmarkCompetition.cs
+++ b/BenchmarkDotNet/BenchmarkCompetition.cs
@@ -37,11 +37,11 @@ namespace BenchmarkDotNet
             ConsoleHelper.NewLine();
             ConsoleHelper.WriteLineHeader("Competition results:");
             var nameWidth = tasks.Max(task => task.Name.Length) + 1;
-            var msWidth = tasks.Max(task => task.Info.Result.AverageMilliseconds.ToString().Length);
+            var msWidth = tasks.Max(task => task.Info.Result.MedianMilliseconds.ToString().Length);
             foreach (var task in tasks)
-                ConsoleHelper.WriteLineStatistic("{0}: {1}ms [Error: {2:00.00}%]", 
-                    task.Name.PadRight(nameWidth), 
-                    task.Info.Result.AverageMilliseconds.ToString().PadLeft(msWidth),
+                ConsoleHelper.WriteLineStatistic("{0}: {1}ms [Error: {2:00.00}%]",
+                    task.Name.PadRight(nameWidth),
+                    task.Info.Result.MedianMilliseconds.ToString().PadLeft(msWidth),
                     task.Info.Result.Error * 100);
         }
     }
diff --git a/BenchmarkDotNet/BenchmarkDotNet.csproj b/BenchmarkDotNet/BenchmarkDotNet.csproj
index 913f3aeb6..12eeee817 100644
--- a/BenchmarkDotNet/BenchmarkDotNet.csproj
+++ b/BenchmarkDotNet/BenchmarkDotNet.csproj
@@ -53,6 +53,7 @@
     <Compile Include="BenchmarkInfo.cs" />
     <Compile Include="BenchmarkRun.cs" />
     <Compile Include="BenchmarkRunList.cs" />
+    <Compile Include="Extensions.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
diff --git a/BenchmarkDotNet/BenchmarkRunList.cs b/BenchmarkDotNet/BenchmarkRunList.cs
index 7be0f2e8e..36f5df162 100644
--- a/BenchmarkDotNet/BenchmarkRunList.cs
+++ b/BenchmarkDotNet/BenchmarkRunList.cs
@@ -26,18 +26,18 @@ namespace BenchmarkDotNet
 
         public void PrintStatistic()
         {
-            ConsoleHelper.WriteLineStatistic("TickStats: Min={0}, Max={1}, Avr={2}, Diff={3:00.00}%",
-                              MinTicks, MaxTicks, AverageTicks, Error * 100);
-            ConsoleHelper.WriteLineStatistic("MsStats: Min={0}, Max={1}, Avr={2}",
-                              MinMilliseconds, MaxMilliseconds, AverageMilliseconds);
+            ConsoleHelper.WriteLineStatistic("TickStats: Min={0}, Max={1}, Median={2}, Diff={3:00.00}%",
+                              MinTicks, MaxTicks, MedianTicks, Error * 100);
+            ConsoleHelper.WriteLineStatistic("MsStats: Min={0}, Max={1}, Median={2}",
+                              MinMilliseconds, MaxMilliseconds, MedianMilliseconds);
         }
 
         public long MinTicks { get { return this.Min(run => run.ElapsedTicks); } }
         public long MaxTicks { get { return this.Max(run => run.ElapsedTicks); } }
-        public long AverageTicks { get { return (long)this.Average(run => run.ElapsedTicks); } }
+        public long MedianTicks { get { return this.Median(run => run.ElapsedTicks); } }
         public long MinMilliseconds { get { return this.Min(run => run.ElapsedMilliseconds); } }
         public long MaxMilliseconds { get { return this.Max(run => run.ElapsedMilliseconds); } }
-        public long AverageMilliseconds { get { return (long)this.Average(run => run.ElapsedMilliseconds); } }
+        public long MedianMilliseconds { get { return this.Median(run => run.ElapsedMilliseconds); } }
         public double Error
         {
             get { return (MaxTicks - MinTicks) * 1.0 / MinTicks; }
diff --git a/BenchmarkDotNet/Extensions.cs b/BenchmarkDotNet/Extensions.cs
new file mode 100644
index 000000000..90940a85e
--- /dev/null
+++ b/BenchmarkDotNet/Extensions.cs
@@ -0,0 +1,20 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace BenchmarkDotNet
+{
+    public static class Extensions
+    {
+        public static long Median<TSource>(this IEnumerable<TSource> source, Func<TSource, long> selector)
+        {
+            var list = source.Select(selector).ToList();
+            if (list.Count == 0)
+                throw new InvalidOperationException("Sequence contains no elements");
+            list.Sort();
+            if (list.Count % 2 == 1)
+                return list[list.Count / 2];
+            return (list[list.Count / 2 - 1] + list[list.Count / 2]) / 2;
+        }
+    }
+}
\ No newline at end of file