[SPARK-6519][ML] Add spark.ml API for bisecting k-means

Author: Yu ISHIKAWA <yuu.ishikawa@gmail.com>

Closes #9604 from yu-iskw/SPARK-6519.

1 files changed, 85 insertions, 0 deletions

diff --git a/mllib/src/test/scala/org/apache/spark/ml/clustering/BisectingKMeansSuite.scala b/mllib/src/test/scala/org/apache/spark/ml/clustering/BisectingKMeansSuite.scala
new file mode 100644
index 0000000000..b26571eb9f
--- /dev/null
+++ b/mllib/src/test/scala/org/apache/spark/ml/clustering/BisectingKMeansSuite.scala
@@ -0,0 +1,85 @@
+/*
+ * 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.ml.clustering
+
+import org.apache.spark.SparkFunSuite
+import org.apache.spark.mllib.util.MLlibTestSparkContext
+import org.apache.spark.sql.DataFrame
+
+class BisectingKMeansSuite extends SparkFunSuite with MLlibTestSparkContext {
+
+  final val k = 5
+  @transient var dataset: DataFrame = _
+
+  override def beforeAll(): Unit = {
+    super.beforeAll()
+    dataset = KMeansSuite.generateKMeansData(sqlContext, 50, 3, k)
+  }
+
+  test("default parameters") {
+    val bkm = new BisectingKMeans()
+
+    assert(bkm.getK === 4)
+    assert(bkm.getFeaturesCol === "features")
+    assert(bkm.getPredictionCol === "prediction")
+    assert(bkm.getMaxIter === 20)
+    assert(bkm.getMinDivisibleClusterSize === 1.0)
+  }
+
+  test("setter/getter") {
+    val bkm = new BisectingKMeans()
+      .setK(9)
+      .setMinDivisibleClusterSize(2.0)
+      .setFeaturesCol("test_feature")
+      .setPredictionCol("test_prediction")
+      .setMaxIter(33)
+      .setSeed(123)
+
+    assert(bkm.getK === 9)
+    assert(bkm.getFeaturesCol === "test_feature")
+    assert(bkm.getPredictionCol === "test_prediction")
+    assert(bkm.getMaxIter === 33)
+    assert(bkm.getMinDivisibleClusterSize === 2.0)
+    assert(bkm.getSeed === 123)
+
+    intercept[IllegalArgumentException] {
+      new BisectingKMeans().setK(1)
+    }
+
+    intercept[IllegalArgumentException] {
+      new BisectingKMeans().setMinDivisibleClusterSize(0)
+    }
+  }
+
+  test("fit & transform") {
+    val predictionColName = "bisecting_kmeans_prediction"
+    val bkm = new BisectingKMeans().setK(k).setPredictionCol(predictionColName).setSeed(1)
+    val model = bkm.fit(dataset)
+    assert(model.clusterCenters.length === k)
+
+    val transformed = model.transform(dataset)
+    val expectedColumns = Array("features", predictionColName)
+    expectedColumns.foreach { column =>
+      assert(transformed.columns.contains(column))
+    }
+    val clusters = transformed.select(predictionColName).map(_.getInt(0)).distinct().collect().toSet
+    assert(clusters.size === k)
+    assert(clusters === Set(0, 1, 2, 3, 4))
+    assert(model.computeCost(dataset) < 0.1)
+  }
+}