def calculate_a1 point
      distances = []
      main_cluster.points.each do |point1|
        distances << euclidean_distance(point, point1).round(2)
      end
      return 0 if distances.size == 1
      (distances.inject(:+)/(distances.size - 1)).round(2)
    end
def calculate_a1 point
      distances = []
      main_cluster.points.each do |point1|
        distances << euclidean_distance(point, point1).round(2)
      end
      return 0 if distances.size == 1
      (distances.inject(:+)/(distances.size - 1)).round(2)
    end
Calculates the a1 value of a cluster