I need to add/delete much more frequently than just updating actually.
On Jan 20, 4:59 pm, Sean Devlin <francoisdev...@gmail.com> wrote: > Gabi, > A similar technique is used with sparse matrices. You usually have > severals arrays, one for the non-zero elements, and another one for > indexing the column and a third for indexing the rows. > > http://pasadena.wr.usgs.gov/office/baagaard/research/papers/thesis/fi... > > This should be fast as long as you're only updating. If you're > inserting/deleting, you might be able to get away with using a > collection of 1D trees. > > Sean > > On Jan 20, 9:18 am, Gabi <bugspy...@gmail.com> wrote: > > > 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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