[jira] [Resolved] (SPARK-7194) Vectors factors method for sparse vectors should accept the output of zipWithIndex

["Sean Owen (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/SPARK-7194?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Sean Owen resolved SPARK-7194.
------------------------------
    Resolution: Won't Fix

Just talked to [~juliet] and she says the {{toSparse}} method is a good fit for her use case.

> Vectors factors method for sparse vectors should accept the output of zipWithIndex
> ----------------------------------------------------------------------------------
>
>                 Key: SPARK-7194
>                 URL: https://issues.apache.org/jira/browse/SPARK-7194
>             Project: Spark
>          Issue Type: Improvement
>          Components: MLlib
>    Affects Versions: 1.3.1
>            Reporter: Juliet Hougland
>            Priority: Minor
>
> Let's say we have an RDD of Array[Double] where zero values are explictly recorded. Ie (0.0, 0.0, 3.2, 0.0...) If we want to transform this into an RDD of sparse vectors, we currently have to:
> arr_doubles.map{ array =>
>    val indexElem: Seq[(Int, Double)] = array.zipWithIndex.filter(tuple =>  tuple._1 != 0.0).map(tuple => (tuple._2, tuple._1))
> Vectors.sparse(arrray.length, indexElem)
> }
> Notice that there is a map step at the end to switch the order of the index and the element value after .zipWithIndex. There should be a factory method on the Vectors class that allows you to avoid this flipping of tuple elements when using zipWithIndex.



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