class Vector2d extends AbstractVector implements Serializable {

    public Vector2d getNormalized()
    {
        double length = getLength();
        return length == 1. ? this : new Vector2d(myX / length, myY / length);
    }

    public  Vector2d(double x, double y);
    public  Vector2d(Vector2d vec);
    public  Vector2d(Vector2i vec);

}