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From: chouqin <git@git.apache.org>
To: reviews@spark.apache.org
Reply-To: reviews@spark.apache.org
Message-ID: <git-pr-2595-spark@git.apache.org>
Subject: [GitHub] spark pull request: [SPARK-3366][MLLIB]Compute best splits
 distrib...
Content-Type: text/plain
Date: Tue, 30 Sep 2014 16:51:51 +0000 (UTC)

GitHub user chouqin opened a pull request:

    https://github.com/apache/spark/pull/2595

    [SPARK-3366][MLLIB]Compute best splits distributively in decision tree

    Currently, all best splits are computed on the driver, which makes the driver a bottleneck for both communication and computation. This PR fix this problem by computed best splits on executors.
    Instead of send all aggregate stats to the driver node, we can send aggregate stats for a node to a particular executor, using `reduceByKey` operation, then we can compute best split for this node there.
    
    Implementation details:
    
    Each node now has a nodeStatsAggregator, which save aggregate stats for all features and bins.
    First use mapPartition to compute node aggregate stats for all nodes in each partition.
    Then transform node aggregate stats to (nodeIndex, nodeStatsAggregator) pairs and use to `reduceByKey` operation to combine nodeStatsAggregator for the same node.
    After all stats have been combined, best splits can be computed for each node based on the node aggregate stats. Best split result is collected to driver to construct the decision tree.
    
    CC: mengxr manishamde jkbradley, please help me review this, thanks.

You can merge this pull request into a Git repository by running:

    $ git pull https://github.com/chouqin/spark dt-dist-agg

Alternatively you can review and apply these changes as the patch at:

    https://github.com/apache/spark/pull/2595.patch

To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:

    This closes #2595
    
----
commit 532993a8274e521795de50d348dbae2a4283f79b
Author: qiping.lqp <qiping.lqp@alibaba-inc.com>
Date:   2014-09-30T07:05:37Z

    Compute best splits distributively in decision tree

commit f00fc22594a936f1abc22ab53365223bf5071d01
Author: qiping.lqp <qiping.lqp@alibaba-inc.com>
Date:   2014-09-30T07:24:29Z

    fix bug

commit 4f564961f699f6a453356de889a80461af8891f8
Author: qiping.lqp <qiping.lqp@alibaba-inc.com>
Date:   2014-09-30T07:29:21Z

    fix bug

commit 5f63d6ce2f43c17bc1758bc2d067c71ef2111220
Author: qiping.lqp <qiping.lqp@alibaba-inc.com>
Date:   2014-09-30T08:10:45Z

    add multiclassification using One-Vs-All strategy

commit 24eacd8ec2770b3ed9cba5d67ed14bc0d3809170
Author: qiping.lqp <qiping.lqp@alibaba-inc.com>
Date:   2014-09-30T08:23:15Z

    fix type-mismatch bug

commit 748bd456809da07b60a984531e83a6b821f71934
Author: qiping.lqp <qiping.lqp@alibaba-inc.com>
Date:   2014-09-30T08:27:39Z

    fix type-mismatch bug

commit e76414fd3fe6df19b9352ff6690f12c7d40ee803
Author: qiping.lqp <qiping.lqp@alibaba-inc.com>
Date:   2014-09-30T08:38:19Z

    fix testsuite

commit b5b0bc2bafe37510adc79bdbda4d2664456fe738
Author: qiping.lqp <qiping.lqp@alibaba-inc.com>
Date:   2014-09-30T08:45:15Z

    fix style

commit a75df27e015b37cd620bc2400c418495ccf9ab39
Author: qiping.lqp <qiping.lqp@alibaba-inc.com>
Date:   2014-09-30T09:40:58Z

    fix test suite

commit bdd2a63f2b90058141e16f996984df955c5687a7
Author: qiping.lqp <qiping.lqp@alibaba-inc.com>
Date:   2014-09-30T10:22:08Z

    fix test suite

commit 7bbb787c5eaf6652e8300c8f0fb4454b555d6d95
Author: chouqin <liqiping1991@gmail.com>
Date:   2014-09-30T16:31:18Z

    add comments

----


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