code: def percentOverlap(x1, x2, size):
    
    nonZeroX1 = np.count_nonzero(x1)
    nonZeroX2 = np.count_nonzero(x2)
    minX1X2 = min(nonZeroX1, nonZeroX2)
    percentOverlap = 0
    if minX1X2 > 0:
      percentOverlap = float(np.dot(x1, x2))/float(minX1X2)
    return percentOverlap
docs: Computes the percentage of overlap between vectors x1 and x2.
  
    @param x1   (array) binary vector
    @param x2   (array) binary vector
    @param size (int)   length of binary vectors
  
    @return percentOverlap (float) percentage overlap between x1 and x2