MemoryError 使用 MultinomilNB

Question

我在对大数据使用 sklearn.naive_bayes.MultinomialNB 进行命名实体识别时出现 MemoryError，其中 train.shape = (416330, 97896)。

data_train = pd.read_csv(path[0] + "train_SENTENCED.tsv", encoding="utf-8", sep='\t', quoting=csv.QUOTE_NONE)
data_test = pd.read_csv(path[0] + "test_SENTENCED.tsv", encoding="utf-8", sep='\t', quoting=csv.QUOTE_NONE)

print('TRAIN_DATA:\n', data_train.tail(5))

# FIT TRANSFORM
X_TRAIN = data_train.drop('Tag', axis=1)
X_TEST = data_test.drop('Tag', axis=1)
v = DictVectorizer(sparse=False)
X_train = v.fit_transform(X_TRAIN.to_dict('records'))
X_test = v.transform(X_TEST.to_dict('records'))
y_train = data_train.Tag.values
y_test = data_test.Tag.values
classes = np.unique(y_train)
classes = classes.tolist()

nb = MultinomialNB(alpha=0.01)
nb.partial_fit(X_train, y_train, classes)
new_classes = classes.copy()
new_classes.pop()
predictions = nb.predict(X_test)

错误输出如下：

Traceback (most recent call last):  
File "naive_bayes_classifier/main.py", line 107, in <module>  
      X_train = v.fit_transform(X_TRAIN.to_dict('records'))  
File "lib/python3.8/site-packages/sklearn/feature_extraction/_dict_vectorizer.py", line 313, in fit_transform  
      return self._transform(X, fitting=True)  
File "lib/python3.8/site-packages/sklearn/feature_extraction/_dict_vectorizer.py", line 282, in _transform  
      result_matrix = result_matrix.toarray()  
File "lib/python3.8/site-packages/scipy/sparse/compressed.py", line 1031, in toarray  
      out = self._process_toarray_args(order, out)  
File "lib/python3.8/site-packages/scipy/sparse/base.py", line 1202, in _process_toarray_args  
      return np.zeros(self.shape, dtype=self.dtype, order=order) 
numpy.core._exceptions.MemoryError: Unable to allocate 304. GiB for an array with shape (416330, 97896) and data type float64

虽然，我为 DictVectorizer(sparse=False, dtype=np.short) 添加了这样的参数，但代码 returns 错误 nb.partial(X_train, y_train, classes) 行。

如何防止此内存错误？有没有合适的方法解决？我考虑过拆分训练集，但由于向量适合相应的数据集，这是正确的解决方案吗？

Answer 1

可悲的是，问题是由于 sklearn 的复杂性，解决这个问题确实需要大量内存。

.partial_fit() 是一个很好的方法，但我建议将您的数据分块成更小的部分，然后在它们上部分拟合分类器。尝试将您的数据集分成小块，看看是否可行。如果您仍然遇到相同的错误，也许可以尝试更小的位

MemoryError 使用 MultinomilNB

MemoryError using MultinomilNB

python

numpy

scikit-learn

out-of-memory