On Jun 4, 2014, at 1:20 PM, Gary Johnson <gwjoh...@uvm.edu> wrote: > - If I operate on a vector with a sequence of r/map and r/filter operations > and finally with "into []" to get back a vector, then I think that fold will > be called within the call to into, and that parallelism should happen > there... right? But if that's right, how do I control the group size that the > call to fold uses in this case? I see how to specify the group size for a > direct call to fold, but not for other function in the library. > > > No, fold will not be called in into. The definition of into uses reduce, > which is single-threaded. What you want is one of the following two > formulations: > > (fold group-size cat append! foldable-collection) ;; if you want to > specify the group size > > (foldcat foldable-collection) ;; if you are happy with the default 512 > group size > > In both cases, the foldable-collection is just one of your (r/map f (r/filter > p? initial-collection)) forms. For it to be foldable though, > initial-collection needs to be a vector, map, or set (i.e., a tree-like > collection). > > I hope that helps.
Definitely helpful. With the fold version, and messing with the group size, I'm seeing much higher multicore utilization and I think I'm seeing speedups too (although it's a little hard to measure because of randomness). I'm also having new problems (pauses that get worse over time... GC?) but I'll experiment more before I bother anyone else with those. Thanks so much Gary, -Lee -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
