[SPARK-14340][EXAMPLE][DOC] Update Examples and User Guide for ml.BisectingKMeans

## What changes were proposed in this pull request?

1, add BisectingKMeans to ml-clustering.md
2, add the missing Scala BisectingKMeansExample
3, create a new datafile `data/mllib/sample_kmeans_data.txt`

## How was this patch tested?

manual tests

Author: Zheng RuiFeng <ruifengz@foxmail.com>

Closes #11844 from zhengruifeng/doc_bkm.

1 files changed, 65 insertions, 0 deletions

diff --git a/examples/src/main/scala/org/apache/spark/examples/ml/BisectingKMeansExample.scala b/examples/src/main/scala/org/apache/spark/examples/ml/BisectingKMeansExample.scala
new file mode 100644
index 0000000000..5f8f2c99cb
--- /dev/null
+++ b/examples/src/main/scala/org/apache/spark/examples/ml/BisectingKMeansExample.scala
@@ -0,0 +1,65 @@
+/*
+ * 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.BisectingKMeans
+// $example off$
+import org.apache.spark.sql.SparkSession
+
+/**
+ * An example demonstrating bisecting k-means clustering.
+ * Run with
+ * {{{
+ * bin/run-example ml.BisectingKMeansExample
+ * }}}
+ */
+object BisectingKMeansExample {
+
+  def main(args: Array[String]): Unit = {
+    // Creates a SparkSession
+    val spark = SparkSession
+      .builder
+      .appName("BisectingKMeansExample")
+      .getOrCreate()
+
+    // $example on$
+    // Loads data.
+    val dataset = spark.read.format("libsvm").load("data/mllib/sample_kmeans_data.txt")
+
+    // Trains a bisecting k-means model.
+    val bkm = new BisectingKMeans().setK(2).setSeed(1)
+    val model = bkm.fit(dataset)
+
+    // Evaluate clustering.
+    val cost = model.computeCost(dataset)
+    println(s"Within Set Sum of Squared Errors = $cost")
+
+    // Shows the result.
+    println("Cluster Centers: ")
+    val centers = model.clusterCenters
+    centers.foreach(println)
+    // $example off$
+
+    spark.stop()
+  }
+}
+// scalastyle:on println
+