Android Open Source - yousense-android-tracker Stats Accumulator

From Project

Back to project page yousense-android-tracker.

License

The source code is released under:

Energy-efficent motion and location tracker for Android. Based on Mattias's power and tracking work. I plan to release it as GPL, once I have a paper published that goes with it. Might also release i...

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Java Source Code

package com.linnap.locationtracker.movement;
//w  w  w . ja  v  a 2s  .c  om
/**
 * Fixed-size buffer for calculating statistical summaries (average, variance) of data.
 * Silently stops accumulating on overflow.
 */
public class StatsAccumulator {

  int size;
  float[] buffer;
  int count;
  float sum;
  
  public StatsAccumulator(int size) {
    this.size = size;
    this.buffer = new float[size];
    this.count = 0;
    this.sum = 0;
  }
  
  public void clear() {
    count = 0;
    sum = 0;
  }
  
  public void add(float value) {
    if (count < size - 1) {
      buffer[count++] = value;
      sum += value;
    }
  }
  
  public float mean() {
    return sum / count;
  }
  
  public float variance() {
    float m = mean(); 
    float squaredDifference = 0;
    for (int i = 0; i < count; ++i)
      squaredDifference += (buffer[i] - m) * (buffer[i] - m);
    return squaredDifference / count;
  }
}

Java Source Code List