[SPARK-1945][MLLIB] Documentation Improvements for Spark 1.0

Standalone application examples are added to 'mllib-linear-methods.md' file written in Java.
This commit is related to the issue [Add full Java Examples in MLlib docs](https://issues.apache.org/jira/browse/SPARK-1945).
Also I changed the name of the sigmoid function from 'logit' to 'f'. This is because the logit function
is the inverse of sigmoid.

Thanks,
Michael

Author: Michael Giannakopoulos <miccagiann@gmail.com>

Closes #1311 from miccagiann/master and squashes the following commits:

8ffe5ab [Michael Giannakopoulos] Update code so as to comply with code standards.
f7ad5cc [Michael Giannakopoulos] Merge remote-tracking branch 'upstream/master'
38d92c7 [Michael Giannakopoulos] Adding PCA, SVD and LBFGS examples in Java. Performing minor updates in the already committed examples so as to eradicate the call of 'productElement' function whenever is possible.
cc0a089 [Michael Giannakopoulos] Modyfied Java examples so as to comply with coding standards.
b1141b2 [Michael Giannakopoulos] Added Java examples for Clustering and Collaborative Filtering [mllib-clustering.md & mllib-collaborative-filtering.md].
837f7a8 [Michael Giannakopoulos] Merge remote-tracking branch 'upstream/master'
15f0eb4 [Michael Giannakopoulos] Java examples included in 'mllib-linear-methods.md' file.

1 files changed, 48 insertions, 1 deletions

diff --git a/docs/mllib-clustering.md b/docs/mllib-clustering.md
index c76ac010d3..561de48910 100644
--- a/docs/mllib-clustering.md
+++ b/docs/mllib-clustering.md
@@ -69,7 +69,54 @@ println("Within Set Sum of Squared Errors = " + WSSSE)
 All of MLlib's methods use Java-friendly types, so you can import and call them there the same
 way you do in Scala. The only caveat is that the methods take Scala RDD objects, while the
 Spark Java API uses a separate `JavaRDD` class. You can convert a Java RDD to a Scala one by
-calling `.rdd()` on your `JavaRDD` object.
+calling `.rdd()` on your `JavaRDD` object. A standalone application example
+that is equivalent to the provided example in Scala is given bellow:
+
+{% highlight java %}
+import org.apache.spark.api.java.*;
+import org.apache.spark.api.java.function.Function;
+import org.apache.spark.mllib.clustering.KMeans;
+import org.apache.spark.mllib.clustering.KMeansModel;
+import org.apache.spark.mllib.linalg.Vector;
+import org.apache.spark.mllib.linalg.Vectors;
+import org.apache.spark.SparkConf;
+
+public class KMeansExample {
+  public static void main(String[] args) {
+    SparkConf conf = new SparkConf().setAppName("K-means Example");
+    JavaSparkContext sc = new JavaSparkContext(conf);
+
+    // Load and parse data
+    String path = "data/mllib/kmeans_data.txt";
+    JavaRDD<String> data = sc.textFile(path);
+    JavaRDD<Vector> parsedData = data.map(
+      new Function<String, Vector>() {
+        public Vector call(String s) {
+          String[] sarray = s.split(" ");
+          double[] values = new double[sarray.length];
+          for (int i = 0; i < sarray.length; i++)
+            values[i] = Double.parseDouble(sarray[i]);
+          return Vectors.dense(values);
+        }
+      }
+    );
+
+    // Cluster the data into two classes using KMeans
+    int numClusters = 2;
+    int numIterations = 20;
+    KMeansModel clusters = KMeans.train(parsedData.rdd(), numClusters, numIterations);
+
+    // Evaluate clustering by computing Within Set Sum of Squared Errors
+    double WSSSE = clusters.computeCost(parsedData.rdd());
+    System.out.println("Within Set Sum of Squared Errors = " + WSSSE);
+  }
+}
+{% endhighlight %}
+
+In order to run the above standalone application using Spark framework make
+sure that you follow the instructions provided at section [Standalone
+Applications](quick-start.html) of the quick-start guide. What is more, you
+should include to your build file *spark-mllib* as a dependency.
 </div>
 
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