Added functions for calculating standard deviation and standard error of running average. They may be useful for statistical evaluation of running average.

Also added function for check fullness of buffer.

Author: V0v1kkk

libraries/RunningAverage/RunningAverage.cpp

@@ -25,12 +25,13 @@
 // 0.2.10 - 2015-09-01 added getFastAverage() and refactored getAverage()
 // http://forum.arduino.cc/index.php?topic=50473
 // 0.2.11 - 2015-09-04 added getMaxInBuffer() getMinInBuffer() request (Antoon)
-//
+// 0.2.12 - 2016-12-01 added GetStandardDeviation() GetStandardError() BufferIsFull() (V0v1kkk)
 // Released to the public domain
 //
 
 #include "RunningAverage.h"
 #include <stdlib.h>
+#include <math.h>
 
 RunningAverage::RunningAverage(const uint8_t size)
 {
@@ -119,13 +120,46 @@ double RunningAverage::GetMaxInBuffer() const
  return max;
 }
 
+// return true if buffer is full
+bool RunningAverage::BufferIsFull() const
+{
+ if (_cnt == _size) return true;
+ return false;
+}
+
 // returns the value of an element if exist, NAN otherwise
 double RunningAverage::getElement(uint8_t idx) const
 {
  if (idx >=_cnt ) return NAN;
  return _ar[idx];
 }
 
+// Return standard deviation of running average. If buffer is empty, return NAN.
+double RunningAverage::GetStandardDeviation() const
+{
+if (_cnt == 0) return NAN;
+ double temp = 0;
+double average = getFastAverage();
+ for (uint8_t i = 0; i < _cnt; i++)
+ {
+temp += pow((_ar[i] - average),2);
+ }
+temp = sqrt(temp/(_cnt - 1));
+ return temp;
+}
+
+// Return standard error of running average. If buffer is empty, return NAN.
+double RunningAverage::GetStandardError() const //++
+{
+double temp = GetStandardDeviation();
+if(temp==NAN) return NAN;
+double n;
+if(_cnt>=30) n= _cnt;
+else n= _cnt - 1;
+temp = temp/sqrt(n);
+return temp;
+}
+
 // fill the average with a value
 // the param number determines how often value is added (weight)
 // number should preferably be between 1 and size

libraries/RunningAverage/RunningAverage.h

@@ -1,8 +1,8 @@
 //
 // FILE: RunningAverage.h
 // AUTHOR: Rob dot Tillaart at gmail dot com
-// VERSION: 0.2.11
-// DATE: 2015-sep-04
+// VERSION: 0.2.12
+// DATE: 2016-dec-01
 // PURPOSE: RunningAverage library for Arduino
 // URL: http://arduino.cc/playground/Main/RunningAverage
 // HISTORY: See RunningAverage.cpp
@@ -17,7 +17,7 @@
 #ifndef RunningAverage_h
 #define RunningAverage_h
 
-#define RUNNINGAVERAGE_LIB_VERSION "0.2.11"
+#define RUNNINGAVERAGE_LIB_VERSION "0.2.12"
 
 #include "Arduino.h"
 
@@ -35,18 +35,27 @@ class RunningAverage
  double getAverage() const; // does iterate over all elements.
  double getFastAverage() const; // reuses previous values.
 
- // returns min/max added to the data-set since last clear
+// return statistical characteristics of the running average
+ double GetStandardDeviation() const; 
+double GetStandardError() const;
+
+// returns min/max added to the data-set since last clear
  double getMin() const { return _min; };
  double getMax() const { return _max; };
 
- // returns min/max from the values in the internal buffer
+// returns min/max from the values in the internal buffer
  double GetMinInBuffer() const;
  double GetMaxInBuffer() const;
+
+// return true if buffer is full
+bool BufferIsFull() const;
 
  double getElement(uint8_t idx) const;
 
  uint8_t getSize() const { return _size; }
  uint8_t getCount() const { return _cnt; }
+
+
 
 protected:
  uint8_t _size;

libraries/RunningAverage/keywords.txt

@@ -21,7 +21,10 @@ fillValue	KEYWORD2
 getElement	KEYWORD2
 getSize	KEYWORD2
 getCount	KEYWORD2
+BufferIsFull()	KEYWORD2
 getFastAverage	KEYWORD2
+GetStandardDeviation	KEYWORD2
+GetStandardError	KEYWORD2
 GetMinInBuffer	KEYWORD2
 GetMaxInBuffer	KEYWORD2