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  1. Spark
  2. SPARK-14371

OnlineLDAOptimizer should not collect stats for each doc in mini-batch to driver

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    Details

    • Type: Improvement
    • Status: Resolved
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 2.3.0
    • Component/s: MLlib
    • Labels:
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      Description

      See this line: https://github.com/apache/spark/blob/5743c6476dbef50852b7f9873112a2d299966ebd/mllib/src/main/scala/org/apache/spark/mllib/clustering/LDAOptimizer.scala#L437

      The second element in each row of "stats" is a list with one Vector for each document in the mini-batch. Those are collected to the driver in this line:
      https://github.com/apache/spark/blob/5743c6476dbef50852b7f9873112a2d299966ebd/mllib/src/main/scala/org/apache/spark/mllib/clustering/LDAOptimizer.scala#L456

      We should not collect those to the driver. Rather, we should do the necessary maps and aggregations in a distributed manner. This will involve modify the Dirichlet expectation implementation. (This JIRA should be done by someone knowledge about online LDA and Spark.)

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              • Assignee:
                acopich Valeriy Avanesov
                Reporter:
                josephkb Joseph K. Bradley
                Shepherd:
                Joseph K. Bradley
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                  Updated:
                  Resolved: