[jira] [Commented] (SYSTEMML-1570) Remove fused sel+ operator

["Matthias Boehm (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/SYSTEMML-1570?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16053552#comment-16053552 ] 

Matthias Boehm commented on SYSTEMML-1570:
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Are there any updates regarding the missing max(X,0), min(X,0) on GPUs?

> Remove fused sel+ operator
> --------------------------
>
>                 Key: SYSTEMML-1570
>                 URL: https://issues.apache.org/jira/browse/SYSTEMML-1570
>             Project: SystemML
>          Issue Type: Task
>            Reporter: Matthias Boehm
>             Fix For: SystemML 1.0
>
>
> The fused operator sel+ (select positive values) is applied for patterns like (X>0)*X and max(X,0) in order to eliminate unnecessary intermediates. It stems from a time when max was sparse-unsafe and hence inefficient over sparse data. However, meanwhile we mark scalar operators as conditionally sparse-safe depending on the given scalar constant c, which applies for max if c<=0. Hence, this sel+ operator is meanwhile completely useless and should be removed.
> Furthermore, we should also generalize the rewrites to rewrite the selection of negative values (X<0)*X to min(X,0)



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