SkLearn2PMML无法确定输出字段的数量

Question

from sklearn.datasets import load_breast_cancer

# Load dataset
data = load_breast_cancer()

# Organize our data
label_names = data['target_names']
labels = data['target']
feature_names = data['feature_names']
features = data['data']

from sklearn.model_selection import train_test_split

# Split our data
train, test, train_labels, test_labels = train_test_split(features, labels, test_size=0.33, random_state=42)

from sklearn.naive_bayes import GaussianNB
from sklearn2pmml import PMMLPipeline

nb_pipeline = PMMLPipeline([
  ('classifier', GaussianNB())
])
#
# Train our classifier
nb_pipeline.fit(train, train_labels)
#
from sklearn2pmml import sklearn2pmml
sklearn2pmml(nb_pipeline, 'nb.pmml', with_repr = True,debug=True)

错误跟踪：

Exception in thread "main" java.lang.IllegalArgumentException: The estimator object of the final step (Python class sklearn.naive_bayes.GaussianNB) does not specify the number of outputs
    at sklearn2pmml.pipeline.PMMLPipeline.initTargetFields(PMMLPipeline.java:564)
    at sklearn2pmml.pipeline.PMMLPipeline.encodePMML(PMMLPipeline.java:132)
    at com.sklearn2pmml.Main.run(Main.java:91)
    at com.sklearn2pmml.Main.main(Main.java:66)

然后我调试，发现model:nb_pipeline不包含键：“target_fields”。因此，如果我想使用GaussianNB，我如何将模型转换成pmml ?希望得到一些想法，谢谢！

Answer 1

这个问题已经在jpmml/sklearn2pmml#357中得到了回答

简而言之，用户似乎在使用传统的Scikit学习版本，该版本不设置Estimator.n_outputs_属性。SkLearn2PMML软件包版本0.86.X渴望拥有它。

可以通过将Scikit升级到1.1.X (或更新)或将SkLearn2PMML升级到0.87.0 (或更新)来解决此错误。