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Matthias Boehm commented on SYSTEMML-1570: ------------------------------------------ thanks [~nakul02] - it's not urgent but I would like to remove this sel+(X) operator in favor of max(X,0) rather sooner than later in order to avoid that people implement additional rewrites or custom conditions on top of it. > 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) -- This message was sent by Atlassian JIRA (v6.3.15#6346)