[chronojump] Added LeastSquares method in new utilMath.cs

[Xavier de Blas <xaviblas src gnome org>]

commit ac58d2e25b9771dfc469735c6002c937bd5d1c2f
Author: Xavier de Blas <xaviblas gmail com>
Date:   Thu Jul 28 11:31:06 2016 +0200

    Added LeastSquares method in new utilMath.cs

 src/utilMath.cs |   88 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 88 insertions(+), 0 deletions(-)
---
diff --git a/src/utilMath.cs b/src/utilMath.cs
new file mode 100644
index 0000000..846e2d8
--- /dev/null
+++ b/src/utilMath.cs
@@ -0,0 +1,88 @@
+/*
+ * This file is part of ChronoJump
+ *
+ * ChronoJump is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or   
+ *    (at your option) any later version.
+ *    
+ * ChronoJump is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
+ *    GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ *  Copyright (C) 2016   Xavier Padullés <x padulles gmail com> 
+ *  Copyright (C) 2016   Xavier de Blas <xaviblas gmail com> 
+ */
+
+public class LeastSquares 
+{
+       //WIP
+
+       public bool Success;
+       public double [] Coef;
+
+       public LeastSquares() {
+               Coef = null;
+               calculate();
+       }
+
+       private double [] calculate() 
+       {
+               int numElements = 3;
+               double [numElements,2] measures = { //TODO: pass this values
+                       { 20,30,40 },
+                       { 5,7,9 } };
+
+               double [3] B = new double[3];
+               for(int i = 0; i++; i < 3){
+                       B[0] = B[0] + measures[i][1];
+                       B[1] = B[0] + measures[i][0]*measures[i][1];
+                       B[2] = B[0] + measures[i][0]*measures[i][0]*measures[i][1];
+               }
+
+               double sumX = 0; //sumatory of the X values
+               double sumX2 = 0; //sumatory of the squared X values
+               double sumX3 = 0; //sumatory of the cubic X values
+
+               for(int i = 0; i++; i < numElements){
+                       sumX = sumX + measures[i][0];
+                       sumX2 = sumX2 + measures[i][0]*measures[i][0];
+                       sumX3 = sumX3 + measures[i][0]*measures[i][0]*measures[i][0];
+               }
+
+               double detA = numElements*sumX2*sumX3 + 2*sumX*sumX2*sumX3 - sumX2*sumX2*sumX2 - 
sumX2*sumX2*sumX3 - numElements*sumX3*sumX3;
+               if(detA != 0){
+                       double [3][3] invA = new double[3][3];
+
+                       invA[0][0] = ( sumX2*sumX3 - sumX3*sumX3) / detA;
+                       invA[0][1] = (-sumX*sumX3  + sumX2*sumX3) / detA;
+                       invA[0][2] = ( sumX*sumX3  - sumX2*sumX2) / detA;
+                       invA[1][1] = ( numElements*sumX3 - sumX2*sumX2) / detA;
+                       invA[1][2] = (-numElements*sumX3 + sumX*sumX2 ) / detA;
+                       invA[2][2] = ( numElements*sumX2 - sumX*sumX  ) / detA;
+
+                       //Simetric matrix
+                       invA[1][0] = invA[0][1];
+                       invA[2][0] = invA[0][2];
+                       invA[2][1] = invA[1][2];
+
+                       //coef = invA * B
+                       double [3] coef = new double[3];
+                       coef[0] = invA[0][0]*B[0] + invA[0][1]*B[1] + invA[0][2]*B[2];
+                       coef[1] = invA[1][0]*B[0] + invA[1][1]*B[1] + invA[1][2]*B[2];
+                       coef[2] = invA[2][0]*B[0] + invA[2][1]*B[1] + invA[2][2]*B[2];
+
+                       Success = true;
+                       Coef = coef;
+               } else {
+                       LogB.Error("Invalid values");
+                       Success = false;
+               }
+       }
+}
+