add centroids and dummy code

src/Program.cs

@@ -1,4 +1,5 @@
-using System.Diagnostics;
+using ScottPlot;
+using System.Diagnostics;
 using System.Drawing;
 using System.Globalization;
 
@@ -7,46 +8,126 @@ namespace kMeans;
 public static class Program
 {
     private const string Coordinates = "coordinates.csv";
-    private const string PlotOut = "plot.png";
     private const int K = 3;
+    private const string PlotOut = "plot.png";
 
-    private static void Main()
+    public static void Main()
     {
         Console.WriteLine("k-Means-Algorithmus");
-        var points = ParseCsv(Coordinates);
-        PlotDiagram(points);
+        var points = ParseCsv(Coordinates).ToList();
+        var centroids = InitializeRandomlyCentroids(points, K).ToList();
+        AssignPointsToCentroids(points, centroids);
+        UpdateCentroids(points, centroids);
+        var plot = CreatePlot(points, centroids);
+        ExportAndPreviewPlot(plot);
     }
 
-    private static IReadOnlyList<Point> ParseCsv(string path)
+    private static bool UpdateCentroids(List<Point> points, List<Point> centroids)
+    {
+        // calculate mean of all points of one cluster.
+        foreach (var centroid in centroids)
+        {
+            var clusterPoints = points.Where(x => x.ClusterId == centroid.ClusterId);
+            double newMeanX = 0;
+            double newMeanY = 0;
+            foreach (var cluster in clusterPoints)
+            {
+                centroid.X = 3;
+            }
+        }
+
+        return false;
+    }
+
+    private static void AssignPointsToCentroids(List<Point> points, List<Point> centroids)
+    {
+        foreach (var point in points)
+        {
+            foreach (var centroid in centroids)
+            {
+                // calculate euclid distance and assign id.
+            }
+        }
+    }
+
+    private static Plot CreatePlot(IEnumerable<Point> points, IEnumerable<Point> centroids)
     {
         var sw = Stopwatch.StartNew();
-        var result = new List<Point>();
+        var plot = new Plot();
+        var colors = new Dictionary<int, Color>();
+        var colorGroups = points.GroupBy(x => x.ClusterId);
+        foreach (var clusterGroup in colorGroups)
+        {
+            var color = plot.GetNextColor();
+            colors.Add(clusterGroup.Key, color);
+            var xs = clusterGroup.Select(p => p.X).ToArray();
+            var ys = clusterGroup.Select(p => p.Y).ToArray();
+            plot.AddScatterPoints(xs, ys, color);
+        }
+
+        const MarkerShape marker = MarkerShape.cross;
+        const float size = 10f;
+        foreach (var centroid in centroids)
+        {
+            var color = colors.TryGetValue(centroid.ClusterId, out var c) ? c : plot.GetNextColor();
+            plot.AddScatterPoints(new[] { centroid.X }, new[] { centroid.Y }, color, size, marker);
+        }
+
+        sw.Stop();
+        Console.WriteLine($"[{nameof(CreatePlot)}] Elapsed: {sw.ElapsedMilliseconds}ms");
+        return plot;
+    }
+
+    private static void ExportAndPreviewPlot(Plot plot)
+    {
+        var sw = Stopwatch.StartNew();
+        plot.SaveFig(PlotOut);
+        Process.Start(new ProcessStartInfo(PlotOut) { UseShellExecute = true });
+        sw.Stop();
+        Console.WriteLine($"[{nameof(ExportAndPreviewPlot)}] Elapsed: {sw.ElapsedMilliseconds}ms");
+    }
+
+    private static IEnumerable<Point> InitializeRandomlyCentroids(IReadOnlyCollection<Point> points, int k)
+    {
+        var minX = points.Min(p => p.X);
+        var maxX = points.Max(p => p.X);
+        var minY = points.Min(p => p.Y);
+        var maxY = points.Max(p => p.Y);
+        var rnd = new Random();
+
+        for (var i = 0; i < k; i++)
+        {
+            var x = (minX + maxX) * rnd.NextDouble();
+            var y = (minY + maxY) * rnd.NextDouble();
+            yield return new Point(x, y, true, i);
+        }
+    }
+
+    private static IEnumerable<Point> ParseCsv(string path)
+    {
         var lines = File.ReadLines(path);
         foreach (var line in lines)
         {
             var current = line.Split(',');
             if (!double.TryParse(current[0], NumberStyles.Any, CultureInfo.InvariantCulture, out var x)) continue;
             if (!double.TryParse(current[1], NumberStyles.Any, CultureInfo.InvariantCulture, out var y)) continue;
-            var point = new Point(x, y);
-            result.Add(point);
+            yield return new Point(x, y, false, -1);
         }
-
-        sw.Stop();
-        Console.WriteLine($"[{nameof(ParseCsv)}] Elapsed: {sw.ElapsedMilliseconds}ms");
-        return result;
     }
+}
 
-    private static void PlotDiagram(IReadOnlyList<Point> points)
+public class Point
+{
+    public Point(double x, double y, bool focusPoint, int clusterId)
     {
-        var sw = Stopwatch.StartNew();
-        var plot = new ScottPlot.Plot();
-        plot.AddScatterPoints(points.Select(p => p.X).ToArray(), points.Select(p => p.Y).ToArray());
-        plot.SaveFig(PlotOut);
-        sw.Stop();
-        Process.Start(new ProcessStartInfo(PlotOut) { UseShellExecute = true });
-        Console.WriteLine($"[{nameof(PlotDiagram)}] Elapsed: {sw.ElapsedMilliseconds}ms");
+        X = x;
+        Y = y;
+        FocusPoint = focusPoint;
+        ClusterId = clusterId;
     }
 
-
-    private record Point(double X, double Y, Color? Color = default, bool Mean = false);
+    public int ClusterId { get; set; }
+    public bool FocusPoint { get; set; }
+    public double X { get; set; }
+    public double Y { get; set; }
 }