[Roam-commit] SF.net SVN: roam: [86] Trunk/Source

[<jon...@us...>]

Revision: 86
          http://roam.svn.sourceforge.net/roam/?rev=86&view=rev
Author:   jonfroehlich
Date:     2007-07-24 00:40:33 -0700 (Tue, 24 Jul 2007)

Log Message:
-----------
1. updated Buffer AddRange (untested)
2. added StandardDeviation to MathUtils

Modified Paths:
--------------
    Trunk/Source/Roam.Common/Collections/Buffer.cs
    Trunk/Source/Roam.Common/Utils/MathUtils.cs
    Trunk/Source/Roam.suo

Modified: Trunk/Source/Roam.Common/Collections/Buffer.cs
===================================================================
--- Trunk/Source/Roam.Common/Collections/Buffer.cs	2007-07-23 07:25:14 UTC (rev 85)
+++ Trunk/Source/Roam.Common/Collections/Buffer.cs	2007-07-24 07:40:33 UTC (rev 86)
@@ -20,7 +20,8 @@
 namespace Roam.Common.Collections
 {
     /// <summary>
-    /// 
+    /// A finite sized memory structure. When the MaxItems count is reached, the next object added
+    /// to the buffer causes the first item to be removed (in a FIFO fashion).
     /// </summary>
     /// <remarks>
     /// 
@@ -134,10 +135,23 @@
 
         public virtual void AddRange(T[] items)
         {
-            while (_listItems.Count + items.Length >= _maxItems)
+            //jeffixme test this method
+            if (items.Length >= _maxItems)
             {
-                _listItems.RemoveFirst();
+                _listItems.Clear();
+                int startIndex = items.Length - _maxItems;
+                for (int i = 0; i < _maxItems; i++)
+                {
+                    _listItems.AddLast(items[startIndex + i]);
+                }
             }
+            else
+            {
+                while (_listItems.Count + items.Length >= _maxItems)
+                {
+                    _listItems.RemoveFirst();
+                }
+            }
 
             foreach (T t in items)
             {

Modified: Trunk/Source/Roam.Common/Utils/MathUtils.cs
===================================================================
--- Trunk/Source/Roam.Common/Utils/MathUtils.cs	2007-07-23 07:25:14 UTC (rev 85)
+++ Trunk/Source/Roam.Common/Utils/MathUtils.cs	2007-07-24 07:40:33 UTC (rev 86)
@@ -86,6 +86,22 @@
             return S / (n - 1);
         }
 
+        /// <summary>
+        /// To understand standard deviation, keep in mind that variance is the average of the squared 
+        /// differences between data points and the mean. Variance is tabulated in units squared. 
+        /// Standard deviation, being the square root of that quantity, therefore measures the spread 
+        /// of data about the mean, measured in the same units as the data.
+        /// </summary>
+        /// <param name="values"></param>
+        /// <returns></returns>
+        public static double StandardDeviation(ICollection<double> values)
+        {
+            double variance = Variance(values);
+            //the standard deviation is the square root of the variance
+            //http://en.wikipedia.org/wiki/Standard_deviation
+            return Math.Sqrt(variance);
+        }
+
         public static Pair<double, double> MinMax(ICollection<double> values)
         {
             double max = double.MinValue;

Modified: Trunk/Source/Roam.suo
===================================================================
(Binary files differ)


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