drag button calibration

src/org/solovyev/util/math/MathUtils.java

@@ -2,17 +2,19 @@ package org.solovyev.util.math;
 
 import org.jetbrains.annotations.NotNull;
 
+import java.util.List;
+
 public class MathUtils {
 
 	public static float getDistance(@NotNull Point2d startPoint,
-			@NotNull Point2d endPoint) {
+									@NotNull Point2d endPoint) {
 		return getNorm(subtract(endPoint, startPoint));
 	}
 
 	public static Point2d subtract(@NotNull Point2d p1, @NotNull Point2d p2) {
 		return new Point2d(p1.getX() - p2.getX(), p1.getY() - p2.getY());
 	}
-	
+
 	public static Point2d sum(@NotNull Point2d p1, @NotNull Point2d p2) {
 		return new Point2d(p1.getX() + p2.getX(), p1.getY() + p2.getY());
 	}
@@ -23,7 +25,7 @@ public class MathUtils {
 	}
 
 	public static float getAngle(@NotNull Point2d startPoint,
-			@NotNull Point2d axisEndPoint, @NotNull Point2d endPoint) {
+								 @NotNull Point2d axisEndPoint, @NotNull Point2d endPoint) {
 		final Point2d axisVector = subtract(axisEndPoint, startPoint);
 		final Point2d vector = subtract(endPoint, startPoint);
 
@@ -36,4 +38,24 @@ public class MathUtils {
 		return (float) Math.acos((-a_2 + b_2 + c_2) / (2 * b * c));
 	}
 
+	public static double countMean(@NotNull List<Double> objects) {
+
+		double sum = 0d;
+		for (Double object : objects) {
+			sum += object;
+		}
+
+		return objects.size() == 0 ? 0d : (sum / objects.size());
+	}
+
+	public static double countStandardDeviation(@NotNull Double mean, @NotNull List<Double> objects) {
+		double sum = 0d;
+
+		for (Double object : objects) {
+			sum += Math.pow(object - mean, 2);
+		}
+
+		return objects.size() == 0 ? 0d : Math.sqrt(sum / objects.size());
+	}
+
 }