Python - Levenstein

Alguna idea para optimizar el algoritmo de levenstein?

def levenshtein_distance(first, second):
if len(first) > len(second):
first, second = second, first
if len(second) == 0:
return len(first)
first_length = len(first) + 1
second_length = len(second) + 1
distance_matrix = [[0] * second_length for x in
range(first_length)]
for i in range(first_length): distance_matrix[i][0] = i
for j in range(second_length): distance_matrix[0][j] = j
for i in xrange(1, first_length):
for j in range(1, second_length):
deletion = distance_matrix[i-1][j] + 1
insertion = distance_matrix[i][j-1] + 1
substitution = distance_matrix[i-1][j-1]
if first[i-1] != second[j-1]:
substitution += 1
distance_matrix[i][j] = min(insertion,
deletion, substitution)
return distance_matrix[first_length-1][second_length-1]

tienes que usar ese algoritmo de manera forzosa? Revisé: http://www.levenshtein.net/ y me parece interesante que sólo necesita un par de arreglos, lo cual mejoriaria del O(mn) actual a un O(m)

ahh no funcionaría