Sample usage for paice

PAICE’s evaluation statistics for stemming algorithms

Given a list of words with their real lemmas and stems according to stemming algorithm under evaluation, counts Understemming Index (UI), Overstemming Index (OI), Stemming Weight (SW) and Error-rate relative to truncation (ERRT).

>>> from nltk.metrics import Paice

Understemming and Overstemming values

>>> lemmas = {'kneel': ['kneel', 'knelt'],
...           'range': ['range', 'ranged'],
...           'ring': ['ring', 'rang', 'rung']}
>>> stems = {'kneel': ['kneel'],
...          'knelt': ['knelt'],
...          'rang': ['rang', 'range', 'ranged'],
...          'ring': ['ring'],
...          'rung': ['rung']}
>>> p = Paice(lemmas, stems)
>>> p.gumt, p.gdmt, p.gwmt, p.gdnt
(4.0, 5.0, 2.0, 16.0)

>>> p.ui, p.oi, p.sw
(0.8..., 0.125..., 0.15625...)

>>> p.errt
1.0

>>> [('{0:.3f}'.format(a), '{0:.3f}'.format(b)) for a, b in p.coords]
[('0.000', '1.000'), ('0.000', '0.375'), ('0.600', '0.125'), ('0.800', '0.125')]