KMean

Esiur.Analysis/Statistics/StatisticalFunctions.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Drawing;
 using System.Linq;
 using System.Text;
 
@@ -35,9 +36,9 @@ namespace Esiur.Analysis.Statistics
 
         public static double RMS(this double[] x)
         {
-            var r = Math.Sqrt(x.Sum(x =>(float) x * (float) x) / x.Length);
+            var r = Math.Sqrt(x.Sum(x => (float)x * (float)x) / x.Length);
             //if (double.IsNaN(r) || double.IsInfinity(r))
-              //  Console.WriteLine();
+            //  Console.WriteLine();
             return r;
         }
 
@@ -46,5 +47,50 @@ namespace Esiur.Analysis.Statistics
         {
             return Covariance(x, y) / (StdDiv(x) * StdDiv(y));
         }
+
+        public static double Distance(this PointF from, PointF to)
+        {
+            return Math.Sqrt(Math.Pow(from.X - to.X, 2) + Math.Pow(from.Y - to.Y, 2));
+        }
+
+        class KClass
+        {
+            public int Id;
+            public PointF Center;
+
+            public override string ToString()
+            {
+                return $"C{Id} <{Center.X}, {Center.Y}>";
+            }
+        }
+
+        public static Dictionary<string, PointF> KMean(PointF[] seeds, PointF[] points)
+        {
+            // calculate distance
+
+
+            var classes = new Dictionary<KClass, List<PointF>>();
+            for (var i = 0; i < seeds.Length; i++)
+                classes.Add(new KClass() { Id = i+1, Center = seeds[i] }, new List<PointF>());
+
+            while (true)
+            {
+
+                foreach (var point in points)
+                {
+                    var cls = classes.Keys.OrderBy(x => x.Center.Distance(point)).First(); 
+                    classes[cls].Add(point);
+                }
+
+                // update center
+                foreach(var kv in classes)
+                {
+                    kv.Key.Center = new PointF() { X = kv.Value.Average(p => p.X), Y = kv.Value.Average(p => p.Y) };
+                    kv.Value.Clear();
+                }
+
+            }
+        }
+
     }
 }