[chronojump] Fixed cvRMSSD (needed sqrt and dividing by mean) (and also *100 to be percentage)

[Xavier de Blas <xaviblas src gnome org>]

commit c2e1a69ee4e46811a35bde15c8f32ade71d56bbf
Author: Xavier de Blas <xaviblas gmail com>
Date:   Wed May 5 13:29:04 2021 +0200

    Fixed cvRMSSD (needed sqrt and dividing by mean) (and also *100 to be percentage)

 src/forceSensor.cs | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)
---
diff --git a/src/forceSensor.cs b/src/forceSensor.cs
index b86c8928..b2a58485 100644
--- a/src/forceSensor.cs
+++ b/src/forceSensor.cs
@@ -1123,15 +1123,25 @@ public class ForceSensorCapturePoints
        }
        private double getVariabilityCVRMSSD (int countA, int countB, int numSamples)
        {
-               //Σ(x_i - x_{i+1})^2 /(n-1))   //note pow should be inside the summation
+               //see a test of this method below:
+               //public static void TestVariabilityCVRMSSD()
+
+               //sqrt(Σ( x_i - x_{i+1})^2 /(n-1)) )   //note pow should be inside the summation
                double sum = 0;
+               double sumForMean = 0;
                for(int i = countA; i < countB; i ++)
                {
                        sum += Math.Pow(forces[i] - forces[i+1], 2);
+                       sumForMean += forces[i];
                }
 
-               return UtilAll.DivideSafe(sum, numSamples -1);
+               double rmssd = Math.Sqrt(UtilAll.DivideSafe(sum, numSamples -1));
+               LogB.Information("RMSSD: " + rmssd.ToString());
+
+               //sumForMean += forces[countB]; //need this?
+               double mean = sumForMean / numSamples;
 
+               return 100 * UtilAll.DivideSafe(rmssd, mean);
        }
        private double getVariabilityOldMethod (int countA, int countB, int numSamples)
        {