Modified MathUtil#mean() return type to Centroid. Furthermore, add ne…

…w function to Point which returns the number of dimensions.

src/de/jail/geometry/schemas/Point.java

@@ -19,6 +19,10 @@ public Point(int dim) {
 		vector = new double[dim];
 	}
 
+	public int getDimension() {
+		return vector.length;
+	}
+
 	/**
 	 * Addition of this point with a defined one.
 	 * 
@@ -30,8 +34,8 @@ public Point add(final Point other) {
 			throw new IllegalArgumentException("argument must not be null");
 		}
 
-		if(!this.equals(other)) {
-			throw new IllegalArgumentException("points not equal means calculation not possible");
+		if(this.getDimension() != other.getDimension()) {
+			throw new IllegalArgumentException("points not equal, means calculation not possible");
 		}
 
 		double[] otherVector = other.getVector();

src/de/jail/utils/MathUtil.java

@@ -5,6 +5,7 @@
 
 import java.util.Collection;
 
+import de.jail.geometry.schemas.Centroid;
 import de.jail.geometry.schemas.Point;
 
 /**
@@ -91,9 +92,11 @@ public static float square(float arg) {
 	 * Calculates the mean from a collection of points.
 	 * 
 	 * @param points collection of points
-	 * @return calculated mean
+	 * @return calculated mean point
+	 * 
+	 * @see Centroid
 	 */
-	public static Point mean(Collection<Point> points) {
+	public static Centroid mean(Collection<Point> points) {
 		if(points == null) {
 			throw new IllegalArgumentException("argument must not be null");
 		}
@@ -112,6 +115,8 @@ public static Point mean(Collection<Point> points) {
 			}
 		}
 
-		return mean.multiply(points.size());
+		Point center = mean.multiply(1.0/(double)points.size());
+
+		return new Centroid(center);
 	}
 }