spark-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Seth Hendrickson (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (SPARK-23704) PySpark access of individual trees in random forest is slow
Date Fri, 22 Jun 2018 22:22:00 GMT

    [ https://issues.apache.org/jira/browse/SPARK-23704?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16520832#comment-16520832
] 

Seth Hendrickson commented on SPARK-23704:
------------------------------------------

Instead of
{code:java}
model.trees[0].transform(test_feat).select('rowNum','probability'){code}
Can you try
{code:java}
trees = model.trees
trees[0].transform(test_feat).select('rowNum','probability'){code}
And time only the second line? The first line actually calls into the JVM and creates new
trees in Python.

> PySpark access of individual trees in random forest is slow
> -----------------------------------------------------------
>
>                 Key: SPARK-23704
>                 URL: https://issues.apache.org/jira/browse/SPARK-23704
>             Project: Spark
>          Issue Type: Improvement
>          Components: ML, PySpark
>    Affects Versions: 2.2.1
>         Environment: PySpark 2.2.1 / Windows 10
>            Reporter: Julian King
>            Priority: Minor
>
> Making predictions from a randomForestClassifier PySpark is much faster than making predictions
from an individual tree contained within the .trees attribute. 
> In fact, the model.transform call without an action is more than 10x slower for an individual
tree vs the model.transform call for the random forest model.
> See [https://stackoverflow.com/questions/49297470/slow-individual-tree-access-for-random-forest-in-pyspark] for
example with timing.
> Ideally:
>  * Getting a prediction from a single tree should be comparable to or faster than getting predictions
from the whole tree
>  * Getting all the predictions from all the individual trees should be comparable in
speed to getting the predictions from the random forest
>  



--
This message was sent by Atlassian JIRA
(v7.6.3#76005)

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


Mime
View raw message