[jira] [Commented] (SPARK-21624) Optimize communication cost of RF/GBT/DT

["Peng Meng (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/SPARK-21624?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16112374#comment-16112374 ] 

Peng Meng commented on SPARK-21624:
-----------------------------------

ping [~josephkb] [~srowen] [~yanboliang] [~mlnick] [~yuhaoyan]

> Optimize communication cost of RF/GBT/DT
> ----------------------------------------
>
>                 Key: SPARK-21624
>                 URL: https://issues.apache.org/jira/browse/SPARK-21624
>             Project: Spark
>          Issue Type: Improvement
>          Components: ML, MLlib
>    Affects Versions: 2.3.0
>            Reporter: Peng Meng
>
> {quote}The implementation of RF is bound by either  the cost of statistics computation on workers or by communicating the sufficient statistics.{quote}
> The statistics are stored in allStats:
> {code:java}
>   /**
>    * Flat array of elements.
>    * Index for start of stats for a (feature, bin) is:
>    *   index = featureOffsets(featureIndex) + binIndex * statsSize
>    */
>   private var allStats: Array[Double] = new Array[Double](allStatsSize)
> {code}
> The size of allStats maybe very large, and it can be very spare, especially on the nodes that near the leave of the tree. 
> I have changed allStats from Array to SparseVector,  my tests show the communication is down by about 50%.



--
This message was sent by Atlassian JIRA
(v6.4.14#64029)

---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscribe@spark.apache.org
For additional commands, e-mail: issues-help@spark.apache.org