[SPARK-18471][MLLIB] In LBFGS, avoid sending huge vectors of 0 #15931
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CostFun used to send a dense vector of zeroes as a closure in a treeAggregate call. To avoid that, we replace treeAggregate by mapPartition + treeReduce, creating a zero vector inside the mapPartition block in-place.
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Can one of the admins verify this patch? |
Member
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See my comments from your previous PR; they still apply. #15905 |
Author
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Sure, sorry I mistakenly pushed a badly rebased version |
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What changes were proposed in this pull request?
The zero for the aggregation used to be shipped into a closure which is
higly problematic when this zero is big (100s of MB is typical for ML).
This change introduces a new overload of treeAggregate which only ships a
function able to generate this zero.
NB This review takes into account preliminary feedback from #15905
How was this patch tested?
Unit tests for core module launched locally
Licensing
This contribution is made on behalf of CRITEO (http://labs.criteo.com/) under the terms of the Apache 2.0 license.