title: Does Pyspark ML KMean have a way to get the explained variance?
body: <p>As I was reading through the ML package for Pyspark <a href="https://spark.apache.org/docs/1.6.1/api/python/pyspark.ml.html#pyspark.ml.clustering.KMeansModel" rel="nofollow noreferrer">here</a>, it seems the KMeanModel doesn't have a way to compute the explained variance in order to draw an elbow curve, to establish the optimal number of clusters.</p>
  
  <p>However in <a href="http://takwatanabe.me/pyspark/generated/generated/pyspark.ml.clustering.KMeans.html" rel="nofollow noreferrer">this</a> example, the user seems to have a <code>computeCost()</code> function. Where did that function come from? I'm not having success in my program.</p>
  
  <p>I am using Spark 1.6. Thanks in advance!</p>