From 72038ff88e7aad5798cae815530ec4e6217938c2 Mon Sep 17 00:00:00 2001
From: Feynman Liang <fliang@databricks.com>
Date: Thu, 9 Jul 2015 16:04:01 -0700
Subject: [PATCH] Add tests referenced against gensim

---
 .../apache/spark/mllib/clustering/LDA.scala   |  1 +
 .../spark/mllib/clustering/LDASuite.scala     | 50 +++++++++++++++++++
 2 files changed, 51 insertions(+)

diff --git a/mllib/src/main/scala/org/apache/spark/mllib/clustering/LDA.scala b/mllib/src/main/scala/org/apache/spark/mllib/clustering/LDA.scala
index 2767504a06b0e..0a234e5b92c61 100644
--- a/mllib/src/main/scala/org/apache/spark/mllib/clustering/LDA.scala
+++ b/mllib/src/main/scala/org/apache/spark/mllib/clustering/LDA.scala
@@ -115,6 +115,7 @@ class LDA private (
    *       [[https://github.com/Blei-Lab/onlineldavb]].
    */
   def setDocConcentration(docConcentration: Vector): this.type = {
+    docConcentration.toArray.iterator
     this.docConcentration = docConcentration
     this
   }
diff --git a/mllib/src/test/scala/org/apache/spark/mllib/clustering/LDASuite.scala b/mllib/src/test/scala/org/apache/spark/mllib/clustering/LDASuite.scala
index 3ac6e8c40fcfa..295060d017dc9 100644
--- a/mllib/src/test/scala/org/apache/spark/mllib/clustering/LDASuite.scala
+++ b/mllib/src/test/scala/org/apache/spark/mllib/clustering/LDASuite.scala
@@ -218,6 +218,56 @@ class LDASuite extends SparkFunSuite with MLlibTestSparkContext {
     }
   }
 
+  test("OnlineLDAOptimizer with asymmetric prior") {
+    def toydata: Array[(Long, Vector)] = Array(
+      Vectors.sparse(6, Array(0, 1), Array(1, 1)),
+      Vectors.sparse(6, Array(1, 2), Array(1, 1)),
+      Vectors.sparse(6, Array(0, 2), Array(1, 1)),
+      Vectors.sparse(6, Array(3, 4), Array(1, 1)),
+      Vectors.sparse(6, Array(3, 5), Array(1, 1)),
+      Vectors.sparse(6, Array(4, 5), Array(1, 1))
+    ).zipWithIndex.map { case (wordCounts, docId) => (docId.toLong, wordCounts) }
+
+    val docs = sc.parallelize(toydata)
+    val op = new OnlineLDAOptimizer().setMiniBatchFraction(1).setTau0(1024).setKappa(0.51)
+      .setGammaShape(1e10)
+    val lda = new LDA().setK(2)
+      .setDocConcentration(Vectors.dense(0.00001, 0.1))
+      .setTopicConcentration(0.01)
+      .setMaxIterations(100)
+      .setOptimizer(op)
+      .setSeed(12345)
+
+    val ldaModel = lda.run(docs)
+    val topicIndices = ldaModel.describeTopics(maxTermsPerTopic = 10)
+    val topics = topicIndices.map { case (terms, termWeights) =>
+      terms.zip(termWeights)
+    }
+
+    /* Verify results with Python:
+
+       import numpy as np
+       from gensim import models
+       corpus = [
+           [(0, 1.0), (1, 1.0)],
+           [(1, 1.0), (2, 1.0)],
+           [(0, 1.0), (2, 1.0)],
+           [(3, 1.0), (4, 1.0)],
+           [(3, 1.0), (5, 1.0)],
+           [(4, 1.0), (5, 1.0)]]
+       np.random.seed(10)
+       lda = models.ldamodel.LdaModel(
+           corpus=corpus, alpha=np.array([0.00001, 0.1]), num_topics=2, update_every=0, passes=100)
+       lda.print_topics()
+
+       > ['0.167*0 + 0.167*1 + 0.167*2 + 0.167*3 + 0.167*4 + 0.167*5',
+          '0.167*0 + 0.167*1 + 0.167*2 + 0.167*4 + 0.167*3 + 0.167*5']
+     */
+    topics.foreach { topic =>
+      assert(topic.forall { case (_, p) => p ~= 0.167 absTol 0.05 })
+    }
+  }
+
   test("model save/load") {
     // Test for LocalLDAModel.
     val localModel = new LocalLDAModel(tinyTopics)