[chronojump] LeastSquares done!

[Xavier Padullés <xpadulles src gnome org>]

commit 4d00421665456256d4453d2d947af70403d612e1
Author: Xavier Padullés <x padulles gmail com>
Date:   Mon Sep 19 16:05:42 2016 +0200

    LeastSquares done!

 src/gui/chronojump.cs |    1 +
 src/utilMath.cs       |   48 ++++++++++++++++++++++++++++++++----------------
 2 files changed, 33 insertions(+), 16 deletions(-)
---
diff --git a/src/gui/chronojump.cs b/src/gui/chronojump.cs
index bc02214..14fb35e 100644
--- a/src/gui/chronojump.cs
+++ b/src/gui/chronojump.cs
@@ -667,6 +667,7 @@ public partial class ChronoJumpWindow
                LogB.Information("Build date:" + buildDate);
 
                LeastSquares ls = new LeastSquares();
+               ls.Test();
                LogB.Information(string.Format("coef = {0} {1} {2}", ls.Coef[0], ls.Coef[1], ls.Coef[2]));
 
                /*
diff --git a/src/utilMath.cs b/src/utilMath.cs
index 839afb2..618374f 100644
--- a/src/utilMath.cs
+++ b/src/utilMath.cs
@@ -19,6 +19,7 @@
  *  Copyright (C) 2016   Xavier de Blas <xaviblas gmail com> 
  */
 
+using System;
 using System.Collections.Generic; //List<T>
 
 public class Point
@@ -41,33 +42,48 @@ public class Point
        }
 }
 
+
 public class LeastSquares 
 {
        //WIP
 
        public bool Success;
        public double [] Coef;
+       private List<Point> measures; 
 
        public LeastSquares() {
                Coef = null;
-               calculate();
        }
 
-       private void calculate() 
+       public void Test()
        {
-               //TODO: pass this values
-               List<Point> measures = new List<Point> { 
+               measures = new List<Point> { 
                        new Point(1, 10.3214), new Point(2, 13.3214), new Point(3, 18.3214),
                            new Point(4, 25.3214), new Point(5, 34.3214), new Point(6, 45.3214), 
                            new Point(7, 58.3214), new Point(8, 73.3214), new Point(9, 90.3214), new 
Point(10, 109.3214) };
 
+               //R testing
+               //x=1:10
+               //y=c(10.3214,13.3214,18.3214,25.3214,34.3214,45.3214,58.3214,73.3214,90.3214,109.3214)
+
+               calculate();
+       }
+
+       public void calculate() 
+       {
                int numMeasures = measures.Count;
 
+               if(numMeasures < 3) {
+                       LogB.Error(string.Format("LeastSquares needs at least three values, 
has:",numMeasures));
+                       Success = false;
+                       return;
+               }
+
                double [] B = new double[3];
                for(int i = 0; i < numMeasures; i++){
                        B[0] = B[0] + measures[i].Y;
-                       B[1] = B[0] + measures[i].X * measures[i].Y;
-                       B[2] = B[0] + measures[i].X * measures[i].X * measures[i].Y;
+                       B[1] = B[1] + measures[i].X * measures[i].Y;
+                       B[2] = B[2] + measures[i].X * measures[i].X * measures[i].Y;
                }
 
                LogB.Information(string.Format("B = {0} {1} {2}", B[0], B[1], B[2]));
@@ -78,22 +94,22 @@ public class LeastSquares
                double sumX4 = 0; //sumatory of the forth power of X values
 
                for(int i = 0; i < numMeasures; i++){
-                       sumX = sumX + measures[i].X;
-                       sumX2 = sumX2 + measures[i].X * measures[i].X;
-                       sumX3 = sumX3 + measures[i].X * measures[i].X * measures[i].X;
-                       sumX4 = sumX3 + measures[i].X * measures[i].X * measures[i].X * measures[i].X;
+                       sumX  = sumX  + measures[i].X;
+                       sumX2 = sumX2 + Math.Pow(measures[i].X,2);
+                       sumX3 = sumX3 + Math.Pow(measures[i].X,3);
+                       sumX4 = sumX4 + Math.Pow(measures[i].X,4);
                }
 
-               double detA = numMeasures*sumX2*sumX4 + 2*sumX*sumX2*sumX3- sumX2*sumX2*sumX2 - 
sumX*sumX*sumX4 - numMeasures*sumX3*sumX3;
+               double detA = numMeasures*sumX2*sumX4 + 2*sumX*sumX2*sumX3 - sumX2*sumX2*sumX2 - 
sumX*sumX*sumX4 - numMeasures*sumX3*sumX3;
                if(detA != 0){
                        double [,] invA = new double[3,3];
 
                        invA[0,0] = ( sumX2*sumX4 - sumX3*sumX3) / detA;
-                       invA[0,1] = (-sumX*sumX4 + sumX2*sumX3) / detA;
-                       invA[0,2] = ( sumX*sumX3  - sumX2*sumX2) / detA;
-                       invA[1,1] = ( numMeasures*sumX4 - sumX2*sumX2) / detA;
-                       invA[1,2] = (-numMeasures*sumX3 + sumX*sumX2 ) / detA;
-                       invA[2,2] = ( numMeasures*sumX2 - sumX*sumX  ) / detA;
+                       invA[0,1] = (-sumX *sumX4 + sumX2*sumX3) / detA;
+                       invA[0,2] = ( sumX *sumX3 - sumX2*sumX2) / detA;
+                       invA[1,1] = ( numMeasures*sumX4 - sumX2*sumX2 ) / detA;
+                       invA[1,2] = (-numMeasures*sumX3 + sumX *sumX2 ) / detA;
+                       invA[2,2] = ( numMeasures*sumX2 - sumX *sumX  ) / detA;
 
                        //Simetric matrix
                        invA[1,0] = invA[0,1];