[SPARK-11629][ML][PYSPARK][DOC] Python example code for Multilayer Perceptron Classification

Add Python example code for Multilayer Perceptron Classification, and make example code in user guide document testable. mengxr

Author: Yanbo Liang <ybliang8@gmail.com>

Closes #9594 from yanboliang/spark-11629.

1 files changed, 56 insertions, 0 deletions

diff --git a/examples/src/main/python/ml/multilayer_perceptron_classification.py b/examples/src/main/python/ml/multilayer_perceptron_classification.py
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+++ b/examples/src/main/python/ml/multilayer_perceptron_classification.py
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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
+
+from pyspark import SparkContext
+from pyspark.sql import SQLContext
+# $example on$
+from pyspark.ml.classification import MultilayerPerceptronClassifier
+from pyspark.ml.evaluation import MulticlassClassificationEvaluator
+from pyspark.mllib.util import MLUtils
+# $example off$
+
+if __name__ == "__main__":
+
+    sc = SparkContext(appName="multilayer_perceptron_classification_example")
+    sqlContext = SQLContext(sc)
+
+    # $example on$
+    # Load training data
+    data = MLUtils.loadLibSVMFile(sc, "data/mllib/sample_multiclass_classification_data.txt")\
+        .toDF()
+    # Split the data into train and test
+    splits = data.randomSplit([0.6, 0.4], 1234)
+    train = splits[0]
+    test = splits[1]
+    # specify layers for the neural network:
+    # input layer of size 4 (features), two intermediate of size 5 and 4
+    # and output of size 3 (classes)
+    layers = [4, 5, 4, 3]
+    # create the trainer and set its parameters
+    trainer = MultilayerPerceptronClassifier(maxIter=100, layers=layers, blockSize=128, seed=1234)
+    # train the model
+    model = trainer.fit(train)
+    # compute precision on the test set
+    result = model.transform(test)
+    predictionAndLabels = result.select("prediction", "label")
+    evaluator = MulticlassClassificationEvaluator(metricName="precision")
+    print("Precision:" + str(evaluator.evaluate(predictionAndLabels)))
+    # $example off$
+
+    sc.stop()