diff options
4 files changed, 438 insertions, 74 deletions
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 37bf88b73b..c8daa2388e 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 @@ -78,35 +78,29 @@ class LDA private ( * * This is the parameter to a symmetric Dirichlet distribution. */ - def getDocConcentration: Double = { - if (this.docConcentration == -1) { - (50.0 / k) + 1.0 - } else { - this.docConcentration - } - } + def getDocConcentration: Double = this.docConcentration /** * Concentration parameter (commonly named "alpha") for the prior placed on documents' * distributions over topics ("theta"). * - * This is the parameter to a symmetric Dirichlet distribution. + * This is the parameter to a symmetric Dirichlet distribution, where larger values + * mean more smoothing (more regularization). * - * This value should be > 1.0, where larger values mean more smoothing (more regularization). * If set to -1, then docConcentration is set automatically. * (default = -1 = automatic) * - * Automatic setting of parameter: - * - For EM: default = (50 / k) + 1. - * - The 50/k is common in LDA libraries. - * - The +1 follows Asuncion et al. (2009), who recommend a +1 adjustment for EM. - * - * Note: The restriction > 1.0 may be relaxed in the future (allowing sparse solutions), - * but values in (0,1) are not yet supported. + * Optimizer-specific parameter settings: + * - EM + * - Value should be > 1.0 + * - default = (50 / k) + 1, where 50/k is common in LDA libraries and +1 follows + * Asuncion et al. (2009), who recommend a +1 adjustment for EM. + * - Online + * - Value should be >= 0 + * - default = (1.0 / k), following the implementation from + * [[https://github.com/Blei-Lab/onlineldavb]]. */ def setDocConcentration(docConcentration: Double): this.type = { - require(docConcentration > 1.0 || docConcentration == -1.0, - s"LDA docConcentration must be > 1.0 (or -1 for auto), but was set to $docConcentration") this.docConcentration = docConcentration this } @@ -126,13 +120,7 @@ class LDA private ( * Note: The topics' distributions over terms are called "beta" in the original LDA paper * by Blei et al., but are called "phi" in many later papers such as Asuncion et al., 2009. */ - def getTopicConcentration: Double = { - if (this.topicConcentration == -1) { - 1.1 - } else { - this.topicConcentration - } - } + def getTopicConcentration: Double = this.topicConcentration /** * Concentration parameter (commonly named "beta" or "eta") for the prior placed on topics' @@ -143,21 +131,20 @@ class LDA private ( * Note: The topics' distributions over terms are called "beta" in the original LDA paper * by Blei et al., but are called "phi" in many later papers such as Asuncion et al., 2009. * - * This value should be > 0.0. * If set to -1, then topicConcentration is set automatically. * (default = -1 = automatic) * - * Automatic setting of parameter: - * - For EM: default = 0.1 + 1. - * - The 0.1 gives a small amount of smoothing. - * - The +1 follows Asuncion et al. (2009), who recommend a +1 adjustment for EM. - * - * Note: The restriction > 1.0 may be relaxed in the future (allowing sparse solutions), - * but values in (0,1) are not yet supported. + * Optimizer-specific parameter settings: + * - EM + * - Value should be > 1.0 + * - default = 0.1 + 1, where 0.1 gives a small amount of smoothing and +1 follows + * Asuncion et al. (2009), who recommend a +1 adjustment for EM. + * - Online + * - Value should be >= 0 + * - default = (1.0 / k), following the implementation from + * [[https://github.com/Blei-Lab/onlineldavb]]. */ def setTopicConcentration(topicConcentration: Double): this.type = { - require(topicConcentration > 1.0 || topicConcentration == -1.0, - s"LDA topicConcentration must be > 1.0 (or -1 for auto), but was set to $topicConcentration") this.topicConcentration = topicConcentration this } @@ -223,14 +210,15 @@ class LDA private ( /** * Set the LDAOptimizer used to perform the actual calculation by algorithm name. - * Currently "em" is supported. + * Currently "em", "online" is supported. */ def setOptimizer(optimizerName: String): this.type = { this.ldaOptimizer = optimizerName.toLowerCase match { case "em" => new EMLDAOptimizer + case "online" => new OnlineLDAOptimizer case other => - throw new IllegalArgumentException(s"Only em is supported but got $other.") + throw new IllegalArgumentException(s"Only em, online are supported but got $other.") } this } @@ -245,8 +233,7 @@ class LDA private ( * @return Inferred LDA model */ def run(documents: RDD[(Long, Vector)]): LDAModel = { - val state = ldaOptimizer.initialState(documents, k, getDocConcentration, getTopicConcentration, - seed, checkpointInterval) + val state = ldaOptimizer.initialize(documents, this) var iter = 0 val iterationTimes = Array.fill[Double](maxIterations)(0) while (iter < maxIterations) { diff --git a/mllib/src/main/scala/org/apache/spark/mllib/clustering/LDAOptimizer.scala b/mllib/src/main/scala/org/apache/spark/mllib/clustering/LDAOptimizer.scala index ffd72a294c..093aa0f315 100644 --- a/mllib/src/main/scala/org/apache/spark/mllib/clustering/LDAOptimizer.scala +++ b/mllib/src/main/scala/org/apache/spark/mllib/clustering/LDAOptimizer.scala @@ -19,13 +19,15 @@ package org.apache.spark.mllib.clustering import java.util.Random -import breeze.linalg.{DenseVector => BDV, normalize} +import breeze.linalg.{DenseVector => BDV, DenseMatrix => BDM, sum, normalize, kron} +import breeze.numerics.{digamma, exp, abs} +import breeze.stats.distributions.{Gamma, RandBasis} import org.apache.spark.annotation.Experimental import org.apache.spark.graphx._ import org.apache.spark.graphx.impl.GraphImpl import org.apache.spark.mllib.impl.PeriodicGraphCheckpointer -import org.apache.spark.mllib.linalg.Vector +import org.apache.spark.mllib.linalg.{Matrices, SparseVector, DenseVector, Vector} import org.apache.spark.rdd.RDD /** @@ -35,7 +37,7 @@ import org.apache.spark.rdd.RDD * hold optimizer-specific parameters for users to set. */ @Experimental -trait LDAOptimizer{ +trait LDAOptimizer { /* DEVELOPERS NOTE: @@ -49,13 +51,7 @@ trait LDAOptimizer{ * Initializer for the optimizer. LDA passes the common parameters to the optimizer and * the internal structure can be initialized properly. */ - private[clustering] def initialState( - docs: RDD[(Long, Vector)], - k: Int, - docConcentration: Double, - topicConcentration: Double, - randomSeed: Long, - checkpointInterval: Int): LDAOptimizer + private[clustering] def initialize(docs: RDD[(Long, Vector)], lda: LDA): LDAOptimizer private[clustering] def next(): LDAOptimizer @@ -80,12 +76,12 @@ trait LDAOptimizer{ * */ @Experimental -class EMLDAOptimizer extends LDAOptimizer{ +class EMLDAOptimizer extends LDAOptimizer { import LDA._ /** - * Following fields will only be initialized through initialState method + * The following fields will only be initialized through the initialize() method */ private[clustering] var graph: Graph[TopicCounts, TokenCount] = null private[clustering] var k: Int = 0 @@ -98,13 +94,23 @@ class EMLDAOptimizer extends LDAOptimizer{ /** * Compute bipartite term/doc graph. */ - private[clustering] override def initialState( - docs: RDD[(Long, Vector)], - k: Int, - docConcentration: Double, - topicConcentration: Double, - randomSeed: Long, - checkpointInterval: Int): LDAOptimizer = { + override private[clustering] def initialize(docs: RDD[(Long, Vector)], lda: LDA): LDAOptimizer = { + + val docConcentration = lda.getDocConcentration + val topicConcentration = lda.getTopicConcentration + val k = lda.getK + + // Note: The restriction > 1.0 may be relaxed in the future (allowing sparse solutions), + // but values in (0,1) are not yet supported. + require(docConcentration > 1.0 || docConcentration == -1.0, s"LDA docConcentration must be" + + s" > 1.0 (or -1 for auto) for EM Optimizer, but was set to $docConcentration") + require(topicConcentration > 1.0 || topicConcentration == -1.0, s"LDA topicConcentration " + + s"must be > 1.0 (or -1 for auto) for EM Optimizer, but was set to $topicConcentration") + + this.docConcentration = if (docConcentration == -1) (50.0 / k) + 1.0 else docConcentration + this.topicConcentration = if (topicConcentration == -1) 1.1 else topicConcentration + val randomSeed = lda.getSeed + // For each document, create an edge (Document -> Term) for each unique term in the document. val edges: RDD[Edge[TokenCount]] = docs.flatMap { case (docID: Long, termCounts: Vector) => // Add edges for terms with non-zero counts. @@ -113,11 +119,9 @@ class EMLDAOptimizer extends LDAOptimizer{ } } - val vocabSize = docs.take(1).head._2.size - // Create vertices. // Initially, we use random soft assignments of tokens to topics (random gamma). - def createVertices(): RDD[(VertexId, TopicCounts)] = { + val docTermVertices: RDD[(VertexId, TopicCounts)] = { val verticesTMP: RDD[(VertexId, TopicCounts)] = edges.mapPartitionsWithIndex { case (partIndex, partEdges) => val random = new Random(partIndex + randomSeed) @@ -130,22 +134,18 @@ class EMLDAOptimizer extends LDAOptimizer{ verticesTMP.reduceByKey(_ + _) } - val docTermVertices = createVertices() - // Partition such that edges are grouped by document this.graph = Graph(docTermVertices, edges).partitionBy(PartitionStrategy.EdgePartition1D) this.k = k - this.vocabSize = vocabSize - this.docConcentration = docConcentration - this.topicConcentration = topicConcentration - this.checkpointInterval = checkpointInterval + this.vocabSize = docs.take(1).head._2.size + this.checkpointInterval = lda.getCheckpointInterval this.graphCheckpointer = new PeriodicGraphCheckpointer[TopicCounts, TokenCount](graph, checkpointInterval) this.globalTopicTotals = computeGlobalTopicTotals() this } - private[clustering] override def next(): EMLDAOptimizer = { + override private[clustering] def next(): EMLDAOptimizer = { require(graph != null, "graph is null, EMLDAOptimizer not initialized.") val eta = topicConcentration @@ -202,9 +202,269 @@ class EMLDAOptimizer extends LDAOptimizer{ graph.vertices.filter(isTermVertex).values.fold(BDV.zeros[Double](numTopics))(_ += _) } - private[clustering] override def getLDAModel(iterationTimes: Array[Double]): LDAModel = { + override private[clustering] def getLDAModel(iterationTimes: Array[Double]): LDAModel = { require(graph != null, "graph is null, EMLDAOptimizer not initialized.") this.graphCheckpointer.deleteAllCheckpoints() new DistributedLDAModel(this, iterationTimes) } } + + +/** + * :: Experimental :: + * + * An online optimizer for LDA. The Optimizer implements the Online variational Bayes LDA + * algorithm, which processes a subset of the corpus on each iteration, and updates the term-topic + * distribution adaptively. + * + * Original Online LDA paper: + * Hoffman, Blei and Bach, "Online Learning for Latent Dirichlet Allocation." NIPS, 2010. + */ +@Experimental +class OnlineLDAOptimizer extends LDAOptimizer { + + // LDA common parameters + private var k: Int = 0 + private var corpusSize: Long = 0 + private var vocabSize: Int = 0 + + /** alias for docConcentration */ + private var alpha: Double = 0 + + /** (private[clustering] for debugging) Get docConcentration */ + private[clustering] def getAlpha: Double = alpha + + /** alias for topicConcentration */ + private var eta: Double = 0 + + /** (private[clustering] for debugging) Get topicConcentration */ + private[clustering] def getEta: Double = eta + + private var randomGenerator: java.util.Random = null + + // Online LDA specific parameters + // Learning rate is: (tau_0 + t)^{-kappa} + private var tau_0: Double = 1024 + private var kappa: Double = 0.51 + private var miniBatchFraction: Double = 0.05 + + // internal data structure + private var docs: RDD[(Long, Vector)] = null + + /** Dirichlet parameter for the posterior over topics */ + private var lambda: BDM[Double] = null + + /** (private[clustering] for debugging) Get parameter for topics */ + private[clustering] def getLambda: BDM[Double] = lambda + + /** Current iteration (count of invocations of [[next()]]) */ + private var iteration: Int = 0 + private var gammaShape: Double = 100 + + /** + * A (positive) learning parameter that downweights early iterations. Larger values make early + * iterations count less. + */ + def getTau_0: Double = this.tau_0 + + /** + * A (positive) learning parameter that downweights early iterations. Larger values make early + * iterations count less. + * Default: 1024, following the original Online LDA paper. + */ + def setTau_0(tau_0: Double): this.type = { + require(tau_0 > 0, s"LDA tau_0 must be positive, but was set to $tau_0") + this.tau_0 = tau_0 + this + } + + /** + * Learning rate: exponential decay rate + */ + def getKappa: Double = this.kappa + + /** + * Learning rate: exponential decay rate---should be between + * (0.5, 1.0] to guarantee asymptotic convergence. + * Default: 0.51, based on the original Online LDA paper. + */ + def setKappa(kappa: Double): this.type = { + require(kappa >= 0, s"Online LDA kappa must be nonnegative, but was set to $kappa") + this.kappa = kappa + this + } + + /** + * Mini-batch fraction, which sets the fraction of document sampled and used in each iteration + */ + def getMiniBatchFraction: Double = this.miniBatchFraction + + /** + * Mini-batch fraction in (0, 1], which sets the fraction of document sampled and used in + * each iteration. + * + * Note that this should be adjusted in synch with [[LDA.setMaxIterations()]] + * so the entire corpus is used. Specifically, set both so that + * maxIterations * miniBatchFraction >= 1. + * + * Default: 0.05, i.e., 5% of total documents. + */ + def setMiniBatchFraction(miniBatchFraction: Double): this.type = { + require(miniBatchFraction > 0.0 && miniBatchFraction <= 1.0, + s"Online LDA miniBatchFraction must be in range (0,1], but was set to $miniBatchFraction") + this.miniBatchFraction = miniBatchFraction + this + } + + /** + * (private[clustering]) + * Set the Dirichlet parameter for the posterior over topics. + * This is only used for testing now. In the future, it can help support training stop/resume. + */ + private[clustering] def setLambda(lambda: BDM[Double]): this.type = { + this.lambda = lambda + this + } + + /** + * (private[clustering]) + * Used for random initialization of the variational parameters. + * Larger value produces values closer to 1.0. + * This is only used for testing currently. + */ + private[clustering] def setGammaShape(shape: Double): this.type = { + this.gammaShape = shape + this + } + + override private[clustering] def initialize( + docs: RDD[(Long, Vector)], + lda: LDA): OnlineLDAOptimizer = { + this.k = lda.getK + this.corpusSize = docs.count() + this.vocabSize = docs.first()._2.size + this.alpha = if (lda.getDocConcentration == -1) 1.0 / k else lda.getDocConcentration + this.eta = if (lda.getTopicConcentration == -1) 1.0 / k else lda.getTopicConcentration + this.randomGenerator = new Random(lda.getSeed) + + this.docs = docs + + // Initialize the variational distribution q(beta|lambda) + this.lambda = getGammaMatrix(k, vocabSize) + this.iteration = 0 + this + } + + override private[clustering] def next(): OnlineLDAOptimizer = { + val batch = docs.sample(withReplacement = true, miniBatchFraction, randomGenerator.nextLong()) + if (batch.isEmpty()) return this + submitMiniBatch(batch) + } + + /** + * Submit a subset (like 1%, decide by the miniBatchFraction) of the corpus to the Online LDA + * model, and it will update the topic distribution adaptively for the terms appearing in the + * subset. + */ + private[clustering] def submitMiniBatch(batch: RDD[(Long, Vector)]): OnlineLDAOptimizer = { + iteration += 1 + val k = this.k + val vocabSize = this.vocabSize + val Elogbeta = dirichletExpectation(lambda) + val expElogbeta = exp(Elogbeta) + val alpha = this.alpha + val gammaShape = this.gammaShape + + val stats: RDD[BDM[Double]] = batch.mapPartitions { docs => + val stat = BDM.zeros[Double](k, vocabSize) + docs.foreach { doc => + val termCounts = doc._2 + val (ids: List[Int], cts: Array[Double]) = termCounts match { + case v: DenseVector => ((0 until v.size).toList, v.values) + case v: SparseVector => (v.indices.toList, v.values) + case v => throw new IllegalArgumentException("Online LDA does not support vector type " + + v.getClass) + } + + // Initialize the variational distribution q(theta|gamma) for the mini-batch + var gammad = new Gamma(gammaShape, 1.0 / gammaShape).samplesVector(k).t // 1 * K + var Elogthetad = digamma(gammad) - digamma(sum(gammad)) // 1 * K + var expElogthetad = exp(Elogthetad) // 1 * K + val expElogbetad = expElogbeta(::, ids).toDenseMatrix // K * ids + + var phinorm = expElogthetad * expElogbetad + 1e-100 // 1 * ids + var meanchange = 1D + val ctsVector = new BDV[Double](cts).t // 1 * ids + + // Iterate between gamma and phi until convergence + while (meanchange > 1e-3) { + val lastgamma = gammad + // 1*K 1 * ids ids * k + gammad = (expElogthetad :* ((ctsVector / phinorm) * expElogbetad.t)) + alpha + Elogthetad = digamma(gammad) - digamma(sum(gammad)) + expElogthetad = exp(Elogthetad) + phinorm = expElogthetad * expElogbetad + 1e-100 + meanchange = sum(abs(gammad - lastgamma)) / k + } + + val m1 = expElogthetad.t + val m2 = (ctsVector / phinorm).t.toDenseVector + var i = 0 + while (i < ids.size) { + stat(::, ids(i)) := stat(::, ids(i)) + m1 * m2(i) + i += 1 + } + } + Iterator(stat) + } + + val statsSum: BDM[Double] = stats.reduce(_ += _) + val batchResult = statsSum :* expElogbeta + + // Note that this is an optimization to avoid batch.count + update(batchResult, iteration, (miniBatchFraction * corpusSize).ceil.toInt) + this + } + + override private[clustering] def getLDAModel(iterationTimes: Array[Double]): LDAModel = { + new LocalLDAModel(Matrices.fromBreeze(lambda).transpose) + } + + /** + * Update lambda based on the batch submitted. batchSize can be different for each iteration. + */ + private[clustering] def update(stat: BDM[Double], iter: Int, batchSize: Int): Unit = { + val tau_0 = this.getTau_0 + val kappa = this.getKappa + + // weight of the mini-batch. + val weight = math.pow(tau_0 + iter, -kappa) + + // Update lambda based on documents. + lambda = lambda * (1 - weight) + + (stat * (corpusSize.toDouble / batchSize.toDouble) + eta) * weight + } + + /** + * Get a random matrix to initialize lambda + */ + private def getGammaMatrix(row: Int, col: Int): BDM[Double] = { + val randBasis = new RandBasis(new org.apache.commons.math3.random.MersenneTwister( + randomGenerator.nextLong())) + val gammaRandomGenerator = new Gamma(gammaShape, 1.0 / gammaShape)(randBasis) + val temp = gammaRandomGenerator.sample(row * col).toArray + new BDM[Double](col, row, temp).t + } + + /** + * For theta ~ Dir(alpha), computes E[log(theta)] given alpha. Currently the implementation + * uses digamma which is accurate but expensive. + */ + private def dirichletExpectation(alpha: BDM[Double]): BDM[Double] = { + val rowSum = sum(alpha(breeze.linalg.*, ::)) + val digAlpha = digamma(alpha) + val digRowSum = digamma(rowSum) + val result = digAlpha(::, breeze.linalg.*) - digRowSum + result + } +} diff --git a/mllib/src/test/java/org/apache/spark/mllib/clustering/JavaLDASuite.java b/mllib/src/test/java/org/apache/spark/mllib/clustering/JavaLDASuite.java index fbe171b4b1..f394d90396 100644 --- a/mllib/src/test/java/org/apache/spark/mllib/clustering/JavaLDASuite.java +++ b/mllib/src/test/java/org/apache/spark/mllib/clustering/JavaLDASuite.java @@ -20,7 +20,6 @@ package org.apache.spark.mllib.clustering; import java.io.Serializable; import java.util.ArrayList; -import org.apache.spark.api.java.JavaRDD; import scala.Tuple2; import org.junit.After; @@ -30,6 +29,7 @@ import org.junit.Before; import org.junit.Test; import org.apache.spark.api.java.JavaPairRDD; +import org.apache.spark.api.java.JavaRDD; import org.apache.spark.api.java.JavaSparkContext; import org.apache.spark.mllib.linalg.Matrix; import org.apache.spark.mllib.linalg.Vector; @@ -109,11 +109,45 @@ public class JavaLDASuite implements Serializable { assert(model.logPrior() < 0.0); } + @Test + public void OnlineOptimizerCompatibility() { + int k = 3; + double topicSmoothing = 1.2; + double termSmoothing = 1.2; + + // Train a model + OnlineLDAOptimizer op = new OnlineLDAOptimizer() + .setTau_0(1024) + .setKappa(0.51) + .setGammaShape(1e40) + .setMiniBatchFraction(0.5); + + LDA lda = new LDA(); + lda.setK(k) + .setDocConcentration(topicSmoothing) + .setTopicConcentration(termSmoothing) + .setMaxIterations(5) + .setSeed(12345) + .setOptimizer(op); + + LDAModel model = lda.run(corpus); + + // Check: basic parameters + assertEquals(model.k(), k); + assertEquals(model.vocabSize(), tinyVocabSize); + + // Check: topic summaries + Tuple2<int[], double[]>[] roundedTopicSummary = model.describeTopics(); + assertEquals(roundedTopicSummary.length, k); + Tuple2<int[], double[]>[] roundedLocalTopicSummary = model.describeTopics(); + assertEquals(roundedLocalTopicSummary.length, k); + } + private static int tinyK = LDASuite$.MODULE$.tinyK(); private static int tinyVocabSize = LDASuite$.MODULE$.tinyVocabSize(); private static Matrix tinyTopics = LDASuite$.MODULE$.tinyTopics(); private static Tuple2<int[], double[]>[] tinyTopicDescription = LDASuite$.MODULE$.tinyTopicDescription(); - JavaPairRDD<Long, Vector> corpus; + private JavaPairRDD<Long, Vector> corpus; } 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 41ec794146..2dcc881f5a 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 @@ -17,6 +17,8 @@ package org.apache.spark.mllib.clustering +import breeze.linalg.{DenseMatrix => BDM} + import org.scalatest.FunSuite import org.apache.spark.mllib.linalg.{Vector, DenseMatrix, Matrix, Vectors} @@ -37,7 +39,7 @@ class LDASuite extends FunSuite with MLlibTestSparkContext { // Check: describeTopics() with all terms val fullTopicSummary = model.describeTopics() - assert(fullTopicSummary.size === tinyK) + assert(fullTopicSummary.length === tinyK) fullTopicSummary.zip(tinyTopicDescription).foreach { case ((algTerms, algTermWeights), (terms, termWeights)) => assert(algTerms === terms) @@ -54,7 +56,7 @@ class LDASuite extends FunSuite with MLlibTestSparkContext { } } - test("running and DistributedLDAModel") { + test("running and DistributedLDAModel with default Optimizer (EM)") { val k = 3 val topicSmoothing = 1.2 val termSmoothing = 1.2 @@ -99,7 +101,7 @@ class LDASuite extends FunSuite with MLlibTestSparkContext { // Check: per-doc topic distributions val topicDistributions = model.topicDistributions.collect() // Ensure all documents are covered. - assert(topicDistributions.size === tinyCorpus.size) + assert(topicDistributions.length === tinyCorpus.length) assert(tinyCorpus.map(_._1).toSet === topicDistributions.map(_._1).toSet) // Ensure we have proper distributions topicDistributions.foreach { case (docId, topicDistribution) => @@ -131,6 +133,87 @@ class LDASuite extends FunSuite with MLlibTestSparkContext { assert(lda.getBeta === 3.0) assert(lda.getTopicConcentration === 3.0) } + + test("OnlineLDAOptimizer initialization") { + val lda = new LDA().setK(2) + val corpus = sc.parallelize(tinyCorpus, 2) + val op = new OnlineLDAOptimizer().initialize(corpus, lda) + op.setKappa(0.9876).setMiniBatchFraction(0.123).setTau_0(567) + assert(op.getAlpha == 0.5) // default 1.0 / k + assert(op.getEta == 0.5) // default 1.0 / k + assert(op.getKappa == 0.9876) + assert(op.getMiniBatchFraction == 0.123) + assert(op.getTau_0 == 567) + } + + test("OnlineLDAOptimizer one iteration") { + // run OnlineLDAOptimizer for 1 iteration to verify it's consistency with Blei-lab, + // [[https://github.com/Blei-Lab/onlineldavb]] + val k = 2 + val vocabSize = 6 + + def docs: Array[(Long, Vector)] = Array( + Vectors.sparse(vocabSize, Array(0, 1, 2), Array(1, 1, 1)), // apple, orange, banana + Vectors.sparse(vocabSize, Array(3, 4, 5), Array(1, 1, 1)) // tiger, cat, dog + ).zipWithIndex.map { case (wordCounts, docId) => (docId.toLong, wordCounts) } + val corpus = sc.parallelize(docs, 2) + + // Set GammaShape large to avoid the stochastic impact. + val op = new OnlineLDAOptimizer().setTau_0(1024).setKappa(0.51).setGammaShape(1e40) + .setMiniBatchFraction(1) + val lda = new LDA().setK(k).setMaxIterations(1).setOptimizer(op).setSeed(12345) + + val state = op.initialize(corpus, lda) + // override lambda to simulate an intermediate state + // [[ 1.1 1.2 1.3 0.9 0.8 0.7] + // [ 0.9 0.8 0.7 1.1 1.2 1.3]] + op.setLambda(new BDM[Double](k, vocabSize, + Array(1.1, 0.9, 1.2, 0.8, 1.3, 0.7, 0.9, 1.1, 0.8, 1.2, 0.7, 1.3))) + + // run for one iteration + state.submitMiniBatch(corpus) + + // verify the result, Note this generate the identical result as + // [[https://github.com/Blei-Lab/onlineldavb]] + val topic1 = op.getLambda(0, ::).inner.toArray.map("%.4f".format(_)).mkString(", ") + val topic2 = op.getLambda(1, ::).inner.toArray.map("%.4f".format(_)).mkString(", ") + assert("1.1101, 1.2076, 1.3050, 0.8899, 0.7924, 0.6950" == topic1) + assert("0.8899, 0.7924, 0.6950, 1.1101, 1.2076, 1.3050" == topic2) + } + + test("OnlineLDAOptimizer with toy data") { + 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).setTau_0(1024).setKappa(0.51) + .setGammaShape(1e10) + val lda = new LDA().setK(2) + .setDocConcentration(0.01) + .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) + } + + // check distribution for each topic, typical distribution is (0.3, 0.3, 0.3, 0.02, 0.02, 0.02) + topics.foreach { topic => + val smalls = topic.filter(t => t._2 < 0.1).map(_._2) + assert(smalls.length == 3 && smalls.sum < 0.2) + } + } + } private[clustering] object LDASuite { |