我正在尝试用两个类对输入进行分类,这是代码。dino
并且crypto
是两个类:
for w, cnt in list(counts.items()): #count is dict with word and it's count value
p_word = vocab[w] / sum(vocab.values())
p_w_given_dino = (word_counts["dino"].get(w, 0.0) + 1) / (sum(word_counts["dino"].values()) + v)
p_w_given_crypto = (word_counts["crypto"].get(w, 0.0) + 1) / (sum(word_counts["crypto"].values()) + v)
log_prob_dino += math.log(cnt * p_w_given_dino / p_word)
log_prob_crypto += math.log(cnt * p_w_given_crypto / p_word)
print("Score(dino) :", math.exp(log_prob_dino + math.log(prior_dino)))
print("Score(crypto):", math.exp(log_prob_crypto + math.log(prior_crypto)))
另一种方法是:
prior_dino = (priors["dino"] / sum(priors.values()))
prior_crypto = (priors["crypto"] / sum(priors.values()))
for w, cnt in list(counts.items()):
p_word = vocab[w] / sum(vocab.values())
p_w_given_dino = (word_counts["dino"].get(w, 0.0) + 1) / (sum(word_counts["dino"].values()) + v)
p_w_given_crypto = (word_counts["crypto"].get(w, 0.0) + 1) / (sum(word_counts["crypto"].values()) + v)
prob_dino *= p_w_given_dino
prob_crypto *= p_w_given_crypto
t_prior_dino = prob_dino * prior_dino
t_prior_crypto = prob_crypto * prior_crypto
在第二种方法中,我得到了非常小的值。
哪一个是正确的,还是两者都正确?