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Common/DTS.Common.Calculations/.svn/pristine/8d/8dc28d306311cd56a44add38f5a086e0d7866451.svn-base

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+using System.Collections.Generic;
+using System.Linq;
+
+namespace DTS.Common.Calculations
+{
+    public static class Resultant
+    {
+        /// <summary>
+        /// generates a resultant channel given input vectors
+        /// Will throw an assertion if lengths of data don't match, or if 
+        /// units don't match
+        /// </summary>
+        /// <param name="channels">List of channels to combine via 
+        /// sum of squares
+        /// </param>
+        /// <returns>
+        /// resultant vector from sum of squares of inputs
+        /// </returns>
+        public static ChannelData GenerateResultantChannel(List<ChannelData> channels)
+        {
+            int length = (from ch in channels select ch.FilteredEU.Length).Max();
+            foreach (var ch in channels) { System.Diagnostics.Trace.Assert(ch.FilteredEU.Length == length); }
+            //make sure the channels are all the same units and lengths, 
+            //we assert here since the higher level should be expected to provide clean inputs
+            var units = (from ch in channels select ch.Units).Distinct();
+            System.Diagnostics.Trace.Assert(units.Count() == 1);
+
+            var values = new List<double>();
+
+            //in a future version we can parallize this for efficiency
+            //values.Add will need to be replaced by an indexer when we do
+            for (int i = 0; i < length; i++)
+            {
+                double d = 0D;
+                foreach (var ch in channels)
+                {
+                    d += ch.FilteredEU[i] * ch.FilteredEU[i];
+                }
+                values.Add(System.Math.Sqrt(d));
+            }
+
+            var cd = new ChannelData(units.First());
+            cd.FilteredEU = values.ToArray();
+            return cd;
+        }
+    }
+}