added std deviation

src/main/java/teetime/framework/pipe/measurements/MeasureCollection.java

@@ -80,6 +80,24 @@ public class MeasureCollection {
 		return result;
 	}
 
+	public double activationVariance() {
+		double expectedValue = averageActivationTime();
+		double result = 0;
+		double count = 0;
+		double temp = 0;
+		for (AbstractStage stage : activationEntries.keySet()) {
+			for (ActivationEntry entry : activationEntries.get(stage)) {
+				temp = entry.getEndTime() - entry.getStartTime() - expectedValue;
+				result += temp * temp;
+				count++;
+			}
+		}
+		if (count != 0) {
+			result = result / count;
+		}
+		return result;
+	}
+
 	public long averageDeactivationTime() {
 		long result = 0;
 		long count = 0;
@@ -97,6 +115,24 @@ public class MeasureCollection {
 		return result;
 	}
 
+	public double deactivationVariance() {
+		double expectedValue = averageDeactivationTime();
+		double result = 0;
+		double count = 0;
+		double temp = 0;
+		for (AbstractStage stage : deactivationEntries.keySet()) {
+			for (DeactivationEntry entry : deactivationEntries.get(stage)) {
+				temp = entry.getEndTime() - entry.getStartTime() - expectedValue;
+				result += temp * temp;
+				count++;
+			}
+		}
+		if (count != 0) {
+			result = result / count;
+		}
+		return result;
+	}
+
 	public long averageThreadStopTime() {
 		long result = 0;
 		long count = 0;
@@ -114,16 +150,41 @@ public class MeasureCollection {
 		return result;
 	}
 
+	public double threadStopTimeVariance() {
+		double expectedValue = averageThreadStopTime();
+		double result = 0;
+		double count = 0;
+		double temp = 0;
+		for (AbstractStage stage : deactivationEntries.keySet()) {
+			for (DeactivationEntry entry : deactivationEntries.get(stage)) {
+				temp = entry.getEndTime() - entry.getThreadTerminationTime() - expectedValue;
+				result += temp * temp;
+				count++;
+			}
+		}
+		if (count != 0) {
+			result = result / count;
+		}
+		return result;
+	}
+
 	@Override
 	public String toString() {
 		String result = "All values are given in nanoseconds \n";
 		String avAT = "Average Activation Time";
+		String aTV = "Activation Time Standard Deviation";
 		String avDT = "Average Deactivation Time";
+		String dTV = "Deactivation Time Standard Deviation";
 		String avTT = "Average Time Thread Termination";
-		int n = Math.max(avAT.length(), Math.max(avDT.length(), avTT.length()));
+		String tTV = "Time Thread Termination Standard Deviation";
+
+		int n = Math.max(avAT.length(), Math.max(avDT.length(), Math.max(avTT.length(), Math.max(aTV.length(), Math.max(dTV.length(), tTV.length())))));
 		result += avAT + spaces(n - avAT.length() + 1) + ": " + averageActivationTime() + "\n";
+		result += aTV + spaces(n - aTV.length() + 1) + ": " + Math.sqrt(activationVariance()) + "\n";
 		result += avDT + spaces(n - avDT.length() + 1) + ": " + averageDeactivationTime() + "\n";
-		result += avTT + spaces(n - avTT.length() + 1) + ": " + averageThreadStopTime();
+		result += dTV + spaces(n - dTV.length() + 1) + ": " + Math.sqrt(deactivationVariance()) + "\n";
+		result += avTT + spaces(n - avTT.length() + 1) + ": " + averageThreadStopTime() + "\n";
+		result += tTV + spaces(n - tTV.length() + 1) + ": " + Math.sqrt(threadStopTimeVariance());
 		return result;
 	}