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#
# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements. See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License. You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
from __future__ import print_function
# $example on$
from pyspark.ml.classification import LogisticRegression, OneVsRest
from pyspark.ml.evaluation import MulticlassClassificationEvaluator
# $example off$
from pyspark.sql import SparkSession
"""
An example of Multiclass to Binary Reduction with One Vs Rest,
using Logistic Regression as the base classifier.
Run with:
bin/spark-submit examples/src/main/python/ml/one_vs_rest_example.py
"""
if __name__ == "__main__":
spark = SparkSession \
.builder \
.appName("PythonOneVsRestExample") \
.getOrCreate()
# $example on$
# load data file.
inputData = spark.read.format("libsvm") \
.load("data/mllib/sample_multiclass_classification_data.txt")
# generate the train/test split.
(train, test) = inputData.randomSplit([0.8, 0.2])
# instantiate the base classifier.
lr = LogisticRegression(maxIter=10, tol=1E-6, fitIntercept=True)
# instantiate the One Vs Rest Classifier.
ovr = OneVsRest(classifier=lr)
# train the multiclass model.
ovrModel = ovr.fit(train)
# score the model on test data.
predictions = ovrModel.transform(test)
# obtain evaluator.
evaluator = MulticlassClassificationEvaluator(metricName="accuracy")
# compute the classification error on test data.
accuracy = evaluator.evaluate(predictions)
print("Test Error : " + str(1 - accuracy))
# $example off$
spark.stop()
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