[SPARK-14434][ML] User guide doc and examples for GaussianMixture in spark.ml

## What changes were proposed in this pull request?

(Please fill in changes proposed in this fix)

Add guide doc and examples for GaussianMixture in Spark.ml in Java, Scala and Python.

## How was this patch tested?

(Please explain how this patch was tested. E.g. unit tests, integration tests, manual tests)

Manual compile and test all examples

Author: wm624@hotmail.com <wm624@hotmail.com>

Closes #12788 from wangmiao1981/example.

1 files changed, 58 insertions, 0 deletions

diff --git a/examples/src/main/scala/org/apache/spark/examples/ml/GaussianMixtureExample.scala b/examples/src/main/scala/org/apache/spark/examples/ml/GaussianMixtureExample.scala
new file mode 100644
index 0000000000..c484ee5556
--- /dev/null
+++ b/examples/src/main/scala/org/apache/spark/examples/ml/GaussianMixtureExample.scala
@@ -0,0 +1,58 @@
+/*
+ * 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
+
+// scalastyle:off println
+
+// $example on$
+import org.apache.spark.ml.clustering.GaussianMixture
+import org.apache.spark.sql.SparkSession
+// $example off$
+
+/**
+ * An example demonstrating Gaussian Mixture Model (GMM).
+ * Run with
+ * {{{
+ * bin/run-example ml.GaussianMixtureExample
+ * }}}
+ */
+object GaussianMixtureExample {
+  def main(args: Array[String]): Unit = {
+    // Creates a SparkSession
+    val spark = SparkSession.builder.appName(s"${this.getClass.getSimpleName}").getOrCreate()
+
+    // $example on$
+    // Loads data
+    val dataset = spark.read.format("libsvm").load("data/mllib/sample_kmeans_data.txt")
+
+    // Trains Gaussian Mixture Model
+    val gmm = new GaussianMixture()
+      .setK(2)
+    val model = gmm.fit(dataset)
+
+    // output parameters of mixture model model
+    for (i <- 0 until model.getK) {
+      println("weight=%f\nmu=%s\nsigma=\n%s\n" format
+        (model.weights(i), model.gaussians(i).mean, model.gaussians(i).cov))
+    }
+    // $example off$
+
+    spark.stop()
+  }
+}
+// scalastyle:on println