[SPARK-11689][ML] Add user guide and example code for LDA under spark.ml

jira: https://issues.apache.org/jira/browse/SPARK-11689

Add simple user guide for LDA under spark.ml and example code under examples/. Use include_example to include example code in the user guide markdown. Check SPARK-11606 for instructions.

Author: Yuhao Yang <hhbyyh@gmail.com>

Closes #9722 from hhbyyh/ldaMLExample.

1 files changed, 30 insertions, 0 deletions

diff --git a/docs/ml-clustering.md b/docs/ml-clustering.md
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+---
+layout: global
+title: Clustering - ML
+displayTitle: <a href="ml-guide.html">ML</a> - Clustering
+---
+
+In this section, we introduce the pipeline API for [clustering in mllib](mllib-clustering.html).
+
+## Latent Dirichlet allocation (LDA)
+
+`LDA` is implemented as an `Estimator` that supports both `EMLDAOptimizer` and `OnlineLDAOptimizer`,
+and generates a `LDAModel` as the base models. Expert users may cast a `LDAModel` generated by
+`EMLDAOptimizer` to a `DistributedLDAModel` if needed.
+
+<div class="codetabs">
+
+Refer to the [Scala API docs](api/scala/index.html#org.apache.spark.ml.clustering.LDA) for more details.
+
+<div data-lang="scala" markdown="1">
+{% include_example scala/org/apache/spark/examples/ml/LDAExample.scala %}
+</div>
+
+<div data-lang="java" markdown="1">
+
+Refer to the [Java API docs](api/java/org/apache/spark/ml/clustering/LDA.html) for more details.
+
+{% include_example java/org/apache/spark/examples/ml/JavaLDAExample.java %}
+</div>
+
+</div>
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