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https://issues.apache.org/jira/browse/SPARK-3272?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14126791#comment-14126791
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Qiping Li commented on SPARK-3272:
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Hi Joseph, I created a PR [#2332|https://github.com/apache/spark/pull/2332] 
based on our discussion.
Could you please help me review this, thanks for your help.

> Calculate prediction for nodes separately from calculating information gain 
> for splits in decision tree
> -------------------------------------------------------------------------------------------------------
>
>                 Key: SPARK-3272
>                 URL: https://issues.apache.org/jira/browse/SPARK-3272
>             Project: Spark
>          Issue Type: Improvement
>          Components: MLlib
>    Affects Versions: 1.0.2
>            Reporter: Qiping Li
>             Fix For: 1.1.0
>
>
> In current implementation, prediction for a node is calculated along with 
> calculation of information gain stats for each possible splits. The value to 
> predict for a specific node is determined, no matter what the splits are.
> To save computation, we can first calculate prediction first and then 
> calculate information gain stats for each split.
> This is also necessary if we want to support minimum instances per node 
> parameters([SPARK-2207|https://issues.apache.org/jira/browse/SPARK-2207]) 
> because when all splits don't satisfy minimum instances requirement , we 
> don't use information gain of any splits. There should be a way to get the 
> prediction value.  



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