[chronojump] ForceSensor: Fixed bug in cvRMSSD calculation

[Xavier de Blas <xaviblas src gnome org>]

commit 8ae5a3d05000066815ce3ff55c5ef6af760e8957
Author: Xavier de Blas <xaviblas gmail com>
Date:   Fri Feb 5 14:56:30 2021 +0100

    ForceSensor: Fixed bug in cvRMSSD calculation

 src/forceSensor.cs | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)
---
diff --git a/src/forceSensor.cs b/src/forceSensor.cs
index 1ba2a3dd..dd57059b 100644
--- a/src/forceSensor.cs
+++ b/src/forceSensor.cs
@@ -958,7 +958,7 @@ public class ForceSensorCapturePoints
                double elapsedSeconds = times[countB]/1000000.0 - times[countA]/1000000.0;
                return sum * UtilAll.DivideSafe(elapsedSeconds, samples);
        }
-
+       
        public void GetVariabilityAndAccuracy(int countA, int countB, int feedbackF, out double variability, 
out double feedbackDifference, bool cvRMSSD)
        {
                if(countA == countB)
@@ -983,18 +983,22 @@ public class ForceSensorCapturePoints
                //feedbackDifference = Math.Abs(feedbackF - avg);
                double sum = 0;
                for(int i = countA; i <= countB; i ++)
+               {
                        sum += Math.Abs(forces[i]-feedbackF);
+               }
 
                feedbackDifference = UtilAll.DivideSafe(sum, numSamples);
        }
        private double getVariabilityCVRMSSD (int countA, int countB, int numSamples)
        {
-               //Σ(x_i - x_{i+1})^2 /(n-1)  )
+               //Σ(x_i - x_{i+1})^2 /(n-1))   //note pow should be inside the summation
                double sum = 0;
                for(int i = countA; i < countB; i ++)
-                       sum += forces[i] - forces[i+1];
+               {
+                       sum += Math.Pow(forces[i] - forces[i+1], 2);
+               }
 
-               return UtilAll.DivideSafe(Math.Pow(sum, 2), numSamples -1);
+               return UtilAll.DivideSafe(sum, numSamples -1);
 
        }
        private double getVariabilityOldMethod (int countA, int countB, int numSamples)