code: def chi_square_distance(point1, point2):
      
      distance = 0.0
      for i in range(len(point1)):
          divider = abs(point1[i]) + abs(point2[i])
          if divider == 0.0:
              continue
  
          distance += ((point1[i] - point2[i]) ** 2.0) / divider
  
      return distance
docs: !
      @brief Calculate Chi square distance between two vectors.
  
      \f[
      dist(a, b) = \sum_{i=0}^{N}\frac{\left ( a_{i} - b_{i} \right )^{2}}{\left | a_{i} \right | + \left | b_{i} \right |};
      \f]
  
      @param[in] point1 (array_like): The first vector.
      @param[in] point2 (array_like): The second vector.
  
      @return (float) Chi square distance between two objects.