[jira] [Updated] (DATAFU-21) Probability weighted sampling without reservoir

["jian wang (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/DATAFU-21?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

jian wang updated DATAFU-21:
----------------------------

    Attachment: DATAFU-21.patch

Initial version of probability weighted sampling UDF.

Remaining:

(1) does it support stratified sampling?

(2) do we need to enforce customer to input the item weight upper bound?

(3) performance metrics report

> Probability weighted sampling without reservoir
> -----------------------------------------------
>
>                 Key: DATAFU-21
>                 URL: https://issues.apache.org/jira/browse/DATAFU-21
>             Project: DataFu
>          Issue Type: New Feature
>         Environment: Mac OS, Linux
>            Reporter: jian wang
>            Assignee: jian wang
>         Attachments: DATAFU-21.patch
>
>
> This issue is used to track investigation on finding a weighted sampler without using internal reservoir. 
> At present, the SimpleRandomSample has implemented a good acceptance-rejection sampling algo on probability random sampling. The weighted sampler could utilize the simple random sample with slight modification.
> One slight modification is:  the present simple random sample generates a uniform random number lies between (0, 1) as the random variable to accept or reject an item. The weighted sample may generate this random variable based on the item's weight and this random number still lies between (0, 1) and each item's random variable remain independent between each other.
> Need further think and experiment the correctness of this solution and how to implement it in an effective way.



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