def compute_q(dict_q, tag, prev_tag, prev_prev_tag, lr1=0.90, lr2=0.09, lr3=0.01):
if lr1 + lr2 + lr3 != 1.0:
raise Exception('summing factors should be 1 !!!')
prob1 = MathUtils.calc_fraction(DictUtils.get_value(dict_q, (tag, prev_tag, prev_prev_tag)),
DictUtils.get_value(dict_q, (prev_tag, prev_prev_tag)))
prob2 = MathUtils.calc_fraction(DictUtils.get_value(dict_q, (tag, prev_tag)),
DictUtils.get_value(dict_q, prev_tag))
prob3 = MathUtils.calc_fraction(DictUtils.get_value(dict_q, tag),
DictUtils.get_value(dict_q, 'ALL'))
return lr1 * prob1 + lr2 * prob2 + lr3 * prob3
def compute_e(word, tag, dict_q, dict_e):
counter = DictUtils.get_value(dict_e, (word, tag))
denominator = DictUtils.get_value(dict_q, tag)
return MathUtils.calc_fraction(counter, denominator)