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https://issues.apache.org/jira/browse/SPARK-17400?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15478819#comment-15478819
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Frank Dai commented on SPARK-17400:
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[~mlnick] After reading the doc of MaxAbsScaler, I think MaxAbsScaler should be 
my choice. Thanks!

I'll close this JIRA ticket.

> MinMaxScaler.transform() outputs DenseVector by default, which causes poor 
> performance
> --------------------------------------------------------------------------------------
>
>                 Key: SPARK-17400
>                 URL: https://issues.apache.org/jira/browse/SPARK-17400
>             Project: Spark
>          Issue Type: Improvement
>          Components: ML, MLlib
>    Affects Versions: 1.6.1, 1.6.2, 2.0.0
>            Reporter: Frank Dai
>
> MinMaxScaler.transform() outputs DenseVector by default, which will cause 
> poor performance and consume a lot of memory.
> The most important line of code is the following:
> https://github.com/apache/spark/blob/master/mllib/src/main/scala/org/apache/spark/ml/feature/MinMaxScaler.scala#L195
> I suggest that the code should calculate the number of non-zero elements in 
> advance, if the number of non-zero elements is less than half of the total 
> elements in the matrix, use SparseVector, otherwise use DenseVector
> Or we can make it configurable by adding  a parameter to 
> MinMaxScaler.transform(), for example MinMaxScaler.transform(isDense: 
> Boolean), so that users can decide whether  their output result is dense or 
> sparse.



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