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70 lines
2.7 KiB
70 lines
2.7 KiB
#!/usr/bin/env python
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from sklearn.naive_bayes import BernoulliNB as _BernoulliNB
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from base import BaseAlgo, ClassifierMixin
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from util.param_util import convert_params
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from codec import codecs_manager
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from util import df_util
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import pandas as pd
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import cexc
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class BernoulliNB(ClassifierMixin, BaseAlgo):
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def __init__(self, options):
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self.handle_options(options)
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out_params = convert_params(
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options.get('params', {}), floats=['alpha', 'binarize'], bools=['fit_prior']
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)
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self.estimator = _BernoulliNB(**out_params)
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def summary(self, options):
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"""Only model_name and mlspl_limits are supported for summary"""
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# Can be modified further to include optional parameters in summary like feature_count = true/false
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if len(options) != 2:
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msg = '"%s" models do not take options for summarization' % self.__class__.__name__
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raise RuntimeError(msg)
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# DataFrame to include class scores
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df = pd.DataFrame(
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{
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'class': self.estimator.classes_,
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'class_count': self.estimator.class_count_.astype(int),
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'class_log_prior': self.estimator.class_log_prior_.round(3),
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},
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index=self.estimator.classes_,
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)
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# renaming column names for display of feature_log_probability
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feature_variables = [
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'log_prob({})'.format(feature) for feature in self.feature_variables
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]
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feature_log_arr = self.estimator.feature_log_prob_.round(3)
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# The default behaviour when encountering categorical fields is to one-hot-encode,
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# causing the number of feature columns to grow by the number of unique labels in the field.
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# currently we do not support feature-summary information for such cases.
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if len(feature_variables) == feature_log_arr.shape[1]:
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# Create dataFrame to include feature probability scores per class
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df_feature_score = pd.DataFrame(
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columns=feature_variables, data=feature_log_arr, index=self.estimator.classes_
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)
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df = df_util.merge_predictions(df, df_feature_score)
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else:
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# Raise a warning to inform the user about depreciated columns, with basic class scores.
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cexc.messages.warn(
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"Unable to display log-probability information for features when categorical fields are supplied."
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)
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return df
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@staticmethod
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def register_codecs():
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from codec.codecs import SimpleObjectCodec
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codecs_manager.add_codec('algos.BernoulliNB', 'BernoulliNB', SimpleObjectCodec)
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codecs_manager.add_codec('sklearn.naive_bayes', 'BernoulliNB', SimpleObjectCodec)
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