[SPARK-14979][ML][PYSPARK] Add examples for GeneralizedLinearRegression

## What changes were proposed in this pull request?
Add Scala/Java/Python examples for ```GeneralizedLinearRegression```.

## How was this patch tested?
They are examples and have been tested offline.

Author: Yanbo Liang <ybliang8@gmail.com>

Closes #12754 from yanboliang/spark-14979.

1 files changed, 83 insertions, 0 deletions

diff --git a/examples/src/main/java/org/apache/spark/examples/ml/JavaGeneralizedLinearRegressionExample.java b/examples/src/main/java/org/apache/spark/examples/ml/JavaGeneralizedLinearRegressionExample.java
new file mode 100644
index 0000000000..3f072d1e50
--- /dev/null
+++ b/examples/src/main/java/org/apache/spark/examples/ml/JavaGeneralizedLinearRegressionExample.java
@@ -0,0 +1,83 @@
+/*
+ * 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.
+ */
+
+package org.apache.spark.examples.ml;
+
+// $example on$
+import java.util.Arrays;
+
+import org.apache.spark.ml.regression.GeneralizedLinearRegression;
+import org.apache.spark.ml.regression.GeneralizedLinearRegressionModel;
+import org.apache.spark.ml.regression.GeneralizedLinearRegressionTrainingSummary;
+import org.apache.spark.sql.Dataset;
+import org.apache.spark.sql.Row;
+// $example off$
+import org.apache.spark.sql.SparkSession;
+
+/**
+ * An example demonstrating generalized linear regression.
+ * Run with
+ * <pre>
+ * bin/run-example ml.JavaGeneralizedLinearRegressionExample
+ * </pre>
+ */
+
+public class JavaGeneralizedLinearRegressionExample {
+
+  public static void main(String[] args) {
+    SparkSession spark = SparkSession
+      .builder()
+      .appName("JavaGeneralizedLinearRegressionExample")
+      .getOrCreate();
+
+    // $example on$
+    // Load training data
+    Dataset<Row> dataset = spark.read().format("libsvm")
+      .load("data/mllib/sample_linear_regression_data.txt");
+
+    GeneralizedLinearRegression glr = new GeneralizedLinearRegression()
+      .setFamily("gaussian")
+      .setLink("identity")
+      .setMaxIter(10)
+      .setRegParam(0.3);
+
+    // Fit the model
+    GeneralizedLinearRegressionModel model = glr.fit(dataset);
+
+    // Print the coefficients and intercept for generalized linear regression model
+    System.out.println("Coefficients: " + model.coefficients());
+    System.out.println("Intercept: " + model.intercept());
+
+    // Summarize the model over the training set and print out some metrics
+    GeneralizedLinearRegressionTrainingSummary summary = model.summary();
+    System.out.println("Coefficient Standard Errors: "
+      + Arrays.toString(summary.coefficientStandardErrors()));
+    System.out.println("T Values: " + Arrays.toString(summary.tValues()));
+    System.out.println("P Values: " + Arrays.toString(summary.pValues()));
+    System.out.println("Dispersion: " + summary.dispersion());
+    System.out.println("Null Deviance: " + summary.nullDeviance());
+    System.out.println("Residual Degree Of Freedom Null: " + summary.residualDegreeOfFreedomNull());
+    System.out.println("Deviance: " + summary.deviance());
+    System.out.println("Residual Degree Of Freedom: " + summary.residualDegreeOfFreedom());
+    System.out.println("AIC: " + summary.aic());
+    System.out.println("Deviance Residuals: ");
+    summary.residuals().show();
+    // $example off$
+
+    spark.stop();
+  }
+}