For example, the complexity of Nested Pitman-Yor Language Model (NPYLM) (Mochihashi, Yamada, and Ueda 2009) is O(N×L 2 ) for bigrams, where N is the length of a character sequence and L is the maximum word length accepted.
the time complexity of NPYLM is O(N 3 ) when the length of the character sequence and the maximum word length are equal to each other.