Uploaded image for project: 'Mahout'
  1. Mahout
  2. MAHOUT-123

Implement Latent Dirichlet Allocation



    • Type: New Feature
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 0.2
    • Fix Version/s: 0.2
    • Component/s: Clustering
    • Labels:


      (For GSoC)


      Latent Dirichlet Allocation (Blei et al, 2003) is a powerful learning
      algorithm for automatically and jointly clustering words into "topics"
      and documents into mixtures of topics, and it has been successfully
      applied to model change in scientific fields over time (Griffiths and
      Steyver, 2004; Hall, et al. 2008). In this project, I propose to
      implement a distributed variant of Latent Dirichlet Allocation using
      MapReduce, and, time permitting, to investigate extensions of LDA and
      possibly more efficient algorithms for distributed inference.

      Detailed Description:

      A topic model is, roughly, a hierarchical Bayesian model that
      associates with each document a probability distribution over
      "topics", which are in turn distributions over words. For instance, a
      topic in a collection of newswire might include words about "sports",
      such as "baseball", "home run", "player", and a document about steroid
      use in baseball might include "sports", "drugs", and "politics". Note
      that the labels "sports", "drugs", and "politics", are post-hoc labels
      assigned by a human, and that the algorithm itself only assigns
      associate words with probabilities. The task of parameter estimation
      in these models is to learn both what these topics are, and which
      documents employ them in what proportions.

      One of the promises of unsupervised learning algorithms like Latent
      Dirichlet Allocation (LDA; Blei et al, 2003) is the ability to take a
      massive collections of documents and condense them down into a
      collection of easily understandable topics. However, all available
      open source implementations of LDA and related topics models are not
      distributed, which hampers their utility. This project seeks to
      correct this shortcoming.

      In the literature, there have been several proposals for paralellzing
      LDA. Newman, et al (2007) proposed to create an "approximate" LDA in
      which each processors gets its own subset of the documents to run
      Gibbs sampling over. However, Gibbs sampling is slow and stochastic by
      its very nature, which is not advantageous for repeated runs. Instead,
      I propose to follow Nallapati, et al. (2007) and use a variational
      approximation that is fast and non-random.


      David M. Blei, J McAuliffe. Supervised Topic Models. NIPS, 2007.

      David M. Blei , Andrew Y. Ng , Michael I. Jordan, Latent dirichlet
      allocation, The Journal of Machine Learning Research, 3, p.993-1022,

      T. L. Griffiths and M. Steyvers. Finding scientiļ¬c topics. Proc Natl
      Acad Sci U S A, 101 Suppl 1: 5228-5235, April 2004.

      David LW Hall, Daniel Jurafsky, and Christopher D. Manning. Studying
      the History of Ideas Using Topic Models. EMNLP, Honolulu, 2008.

      Ramesh Nallapati, William Cohen, John Lafferty, Parallelized
      variational EM for Latent Dirichlet Allocation: An experimental
      evaluation of speed and scalability, ICDM workshop on high performance
      data mining, 2007.

      Newman, D., Asuncion, A., Smyth, P., & Welling, M. Distributed
      Inference for Latent Dirichlet Allocation. NIPS, 2007.

      Xuerui Wang , Andrew McCallum, Topics over time: a non-Markov
      continuous-time model of topical trends. KDD, 2006

      Wolfe, J., Haghighi, A, and Klein, D. Fully distributed EM for very
      large datasets. ICML, 2008.


        1. MAHOUT-123.patch
          59 kB
          David Leo Wright Hall
        2. MAHOUT-123.patch
          60 kB
          Grant Ingersoll
        3. MAHOUT-123.patch
          58 kB
          David Leo Wright Hall
        4. MAHOUT-123.patch
          57 kB
          David Leo Wright Hall
        5. MAHOUT-123.patch
          46 kB
          David Leo Wright Hall
        6. MAHOUT-123.patch
          43 kB
          David Leo Wright Hall
        7. MAHOUT-123.patch
          33 kB
          David Leo Wright Hall
        8. MAHOUT-123.patch
          0.1 kB
          David Leo Wright Hall
        9. MAHOUT-123.patch
          33 kB
          David Leo Wright Hall
        10. MAHOUT-123.patch
          26 kB
          David Leo Wright Hall
        11. lda.patch
          27 kB
          David Leo Wright Hall



            • Assignee:
              gsingers Grant Ingersoll
              dlwh David Leo Wright Hall
            • Votes:
              0 Vote for this issue
              3 Start watching this issue


              • Created:

                Time Tracking

                Original Estimate - 504h
                Remaining Estimate - 504h
                Time Spent - Not Specified
                Not Specified