Thanks Alex. Good summary. I think this can be added to https://clojure.org/reference/transducers
On Tue, Nov 28, 2017 at 10:54 AM, Alex Miller <a...@puredanger.com> wrote: > I would say transducers are preferable when: > > 1) you have reducible collections > 2) you have a lot of pipelined transformations (transducers handle these > in one pass with no intermediate data) > 3) the number of elements is "large" (this amplifies the memory and perf > savings from #2) > 4) you put to produce a concrete output collection (seqs need an extra > step to pour the seq into a collection; transducers can create it directly) > 5) you want a reusable transformation that can be used in multiple > contexts (reduction, sequence, core.async, etc) > > On Monday, November 27, 2017 at 8:33:50 PM UTC-6, Jiacai Liu wrote: >> >> > Also, most of the performance boost from transducers is due to less >> garbage being created, and some times the heap of the JVM is so large >> you'll never see much change from switching to transducers. >> >> Thanks for this tip. I seldom use transducers in my daily work, and I was >> convinced transducers are a better choice in whatever situation after >> reading some articles. But the test shows it isn't an easy choice, only >> when do something reducible, will transducers make more sense. >> >> On Tuesday, November 28, 2017 at 5:07:10 AM UTC+8, tbc++ wrote: >>> >>> >> Also, I think the transducer version should always be faster, no >>> matter the size of the source collection (no threshold). >>> >>> It's a bit more complicated than that, mostly because transducer >>> pipelines require about 2 allocations per step during creation. Also, most >>> of the performance boost from transducers is due to less garbage being >>> created, and some times the heap of the JVM is so large you'll never see >>> much change from switching to transducers. >>> >>> Don't get me wrong, transducers are great and I often default to them >>> over seqs, but in micro-benchmarks like this there's too much in play to >>> always see a 100% performance boost. >>> >>> On Mon, Nov 27, 2017 at 12:55 PM, David Bürgin <dbue...@gluet.ch> wrote: >>> >>>> Jiacai – >>>> >>>> I saw you updated the gist. Just in case it passed you by: performance >>>> profits from the source collection being reducible. So pouring ‘dataset’ >>>> into a vector beforehand should speed up the processing quite a bit. >>>> >>>> Also, I think the transducer version should always be faster, no matter >>>> the size of the source collection (no threshold). >>>> >>>> >>>> -- >>>> David >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "Clojure" group. >>>> To post to this group, send email to clo...@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+u...@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+u...@googlegroups.com. >>>> For more options, visit https://groups.google.com/d/optout. >>>> >>> >>> >>> >>> -- >>> “One of the main causes of the fall of the Roman Empire was that–lacking >>> zero–they had no way to indicate successful termination of their C >>> programs.” >>> (Robert Firth) >>> >> -- > 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. > -- 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.
