def get_radius(self):
if (self.__radius is not None):<EOL><INDENT>return self.__radius;<EOL><DEDENT>centroid = self.get_centroid();<EOL>radius_part_1 = self.square_sum;<EOL>radius_part_2 = <NUM_LIT:0.0>;<EOL>radius_part_3 = <NUM_LIT:0.0>;<EOL>if (type(centroid) == list):<EOL><INDENT>radius_part_2 = <NUM_LIT> * sum(list_math_multiplication(self.linear_sum, centroid));<EOL>radius_part_3 = self.number_points * sum(list_math_multiplication(centroid, centroid));<EOL><DEDENT>else:<EOL><INDENT>radius_part_2 = <NUM_LIT> * self.linear_sum * centroid;<EOL>radius_part_3 = self.number_points * centroid * centroid;<EOL><DEDENT>self.__radius = ( (<NUM_LIT:1.0> / self.number_points) * (radius_part_1 - radius_part_2 + radius_part_3) ) ** <NUM_LIT:0.5>;<EOL>return self.__radius<EOL>
!
        @brief Calculates radius of cluster that is represented by the entry.
        @details It's calculated once when it's requested after the last changes.

        @return (double) Radius of cluster that is represented by the entry.