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Diffstat (limited to 'examples/src/main/python/ml/simple_params_example.py')
-rw-r--r-- | examples/src/main/python/ml/simple_params_example.py | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/examples/src/main/python/ml/simple_params_example.py b/examples/src/main/python/ml/simple_params_example.py new file mode 100644 index 0000000000..3933d59b52 --- /dev/null +++ b/examples/src/main/python/ml/simple_params_example.py @@ -0,0 +1,98 @@ +# +# 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 + +import pprint +import sys + +from pyspark import SparkContext +from pyspark.ml.classification import LogisticRegression +from pyspark.mllib.linalg import DenseVector +from pyspark.mllib.regression import LabeledPoint +from pyspark.sql import SQLContext + +""" +A simple example demonstrating ways to specify parameters for Estimators and Transformers. +Run with: + bin/spark-submit examples/src/main/python/ml/simple_params_example.py +""" + +if __name__ == "__main__": + if len(sys.argv) > 1: + print("Usage: simple_params_example", file=sys.stderr) + exit(1) + sc = SparkContext(appName="PythonSimpleParamsExample") + sqlContext = SQLContext(sc) + + # prepare training data. + # We create an RDD of LabeledPoints and convert them into a DataFrame. + # Spark DataFrames can automatically infer the schema from named tuples + # and LabeledPoint implements __reduce__ to behave like a named tuple. + training = sc.parallelize([ + LabeledPoint(1.0, DenseVector([0.0, 1.1, 0.1])), + LabeledPoint(0.0, DenseVector([2.0, 1.0, -1.0])), + LabeledPoint(0.0, DenseVector([2.0, 1.3, 1.0])), + LabeledPoint(1.0, DenseVector([0.0, 1.2, -0.5]))]).toDF() + + # Create a LogisticRegression instance with maxIter = 10. + # This instance is an Estimator. + lr = LogisticRegression(maxIter=10) + # Print out the parameters, documentation, and any default values. + print("LogisticRegression parameters:\n" + lr.explainParams() + "\n") + + # We may also set parameters using setter methods. + lr.setRegParam(0.01) + + # Learn a LogisticRegression model. This uses the parameters stored in lr. + model1 = lr.fit(training) + + # Since model1 is a Model (i.e., a Transformer produced by an Estimator), + # we can view the parameters it used during fit(). + # This prints the parameter (name: value) pairs, where names are unique IDs for this + # LogisticRegression instance. + print("Model 1 was fit using parameters:\n") + pprint.pprint(model1.extractParamMap()) + + # We may alternatively specify parameters using a parameter map. + # paramMap overrides all lr parameters set earlier. + paramMap = {lr.maxIter: 20, lr.threshold: 0.55, lr.probabilityCol: "myProbability"} + + # Now learn a new model using the new parameters. + model2 = lr.fit(training, paramMap) + print("Model 2 was fit using parameters:\n") + pprint.pprint(model2.extractParamMap()) + + # prepare test data. + test = sc.parallelize([ + LabeledPoint(1.0, DenseVector([-1.0, 1.5, 1.3])), + LabeledPoint(0.0, DenseVector([3.0, 2.0, -0.1])), + LabeledPoint(0.0, DenseVector([0.0, 2.2, -1.5]))]).toDF() + + # Make predictions on test data using the Transformer.transform() method. + # LogisticRegressionModel.transform will only use the 'features' column. + # Note that model2.transform() outputs a 'myProbability' column instead of the usual + # 'probability' column since we renamed the lr.probabilityCol parameter previously. + result = model2.transform(test) \ + .select("features", "label", "myProbability", "prediction") \ + .collect() + + for row in result: + print("features=%s,label=%s -> prob=%s, prediction=%s" + % (row.features, row.label, row.myProbability, row.prediction)) + + sc.stop() |