[jira] [Assigned] (ARROW-1571) [C++] Implement argsort kernels (sort indices) for integers using O(n) counting sort

["Yibo Cai (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/ARROW-1571?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Yibo Cai reassigned ARROW-1571:
-------------------------------

    Assignee: Yibo Cai

> [C++] Implement argsort kernels (sort indices) for integers using O(n) counting sort
> ------------------------------------------------------------------------------------
>
>                 Key: ARROW-1571
>                 URL: https://issues.apache.org/jira/browse/ARROW-1571
>             Project: Apache Arrow
>          Issue Type: New Feature
>          Components: C++
>            Reporter: Wes McKinney
>            Assignee: Yibo Cai
>            Priority: Major
>              Labels: Analytics
>             Fix For: 2.0.0
>
>         Attachments: e5-2650.png
>
>
> This function requires knowledge of the minimum and maximum of an array. If it is small enough, then an array of size {{maximum - minimum}} can be constructed and used to tabulate value frequencies and then compute the sort indices (this is called "grade up" or "grade down" in APL languages). There is generally a cross-over point where this function performs worse than mergesort or quicksort due to data locality issues



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