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https://issues.apache.org/jira/browse/DATAFU-21?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13944358#comment-13944358
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Xiangrui Meng commented on DATAFU-21:
-------------------------------------

Wow, I'm surprised to see you have made this far! I didn't check the details. 
But since you know you need to solve a nonlinear equation for q1 and q2, where 
data is distributed, you are probably on the right direction. You can 
discretize the weights to compress the data while maintaining a certain level 
of accuracy, then solve the relaxed inequality on a single node.

> 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
>
> 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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