These vectors represent trees which need to updated very frequently. So If there was an efficient way to use transients to represent transient trees the whole process would be much more efficient (so each update to a tree would be done in place instead of creating new one.) As discussed above, naive usage of transients won't help. Another approach would be implement in Java, but I wish there would some way to achieve this directly from Clojure. Now that I think about it, maybe the solution is to represent the tree as one dimensional vector instead of nested one (any good clojure algorithm for this ? Representing and traversing non binary trees as one dimensional vector?)
Jan 20, 12:53 pm, Christophe Grand <christo...@cgrand.net> wrote: > Hi Gabi! > > Can you tell us more about your problem, what do those deeply nested > vectors represent and how are you going to update them? (are all > updates batched in one part of your program?) > > With transients current implementation you can't write an efficient update-in! > > Christophe > > > > On Wed, Jan 20, 2010 at 9:15 AM, Gabi <bugspy...@gmail.com> wrote: > > Guys, I really need your expertise here. > > I have lots of deeply nested vectors, which i need to manipulate > > frequently (thousands of times) > > What is the most effective way to do this ? > > > On Jan 17, 4:27 pm, Gabi <bugspy...@gmail.com> wrote: > >> Right. I thought that transient performing deep 'transientivity'. > >> Here is a fixed version. It takes a regular coll converts whatever it > >> can to transient and update the stuff. > >> The problem is that doing persistent!(assoc!(transient m)) on each > >> level probably misses the whole point of performance. > >> So while it work, it probably slower than the regular update-in. > >> I need a better solution. > > >> (defn update-in!! > >> "modified version of core/update-in that works on, and return > >> transiants" > >> ([m [k & ks] f & args] > >> (if ks > >> (persistent!(assoc! (transient m) k (apply update-in!! (get m k) > >> ks f args))) > >> (persistent!(assoc! (transient m) k (apply f (get m k) args)))))) > > >> On Jan 17, 3:57 pm, Chouser <chou...@gmail.com> wrote: > > >> > On Sun, Jan 17, 2010 at 8:25 AM, Gabi <bugspy...@gmail.com> wrote: > > >> > >> user=> (persistent!(update-in!(transient v) [0] reverse)) > > >> > > Forgot to mention that v in the example is defined to [[1 2] [3 4]] > > >> > So you've got a transient vector of persistent vectors of > >> > numbers. The problem is your update-in! then calls assoc! on > >> > each level, but of course assoc! on the inner persistent vector > >> > fails. > > >> > You either need to make the inner vectors transient (and then > >> > call persist! on them when you're done) or use assoc! only at the > >> > outer level. > > >> > --Chouserhttp://joyofclojure.com/ > > > -- > > 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 > > -- > Professional:http://cgrand.net/(fr) > On Clojure:http://clj-me.cgrand.net/(en)
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