Jose, This is an old thread, and whatever problems you might be dealing with now, they're probably not the same ones as when the thread was active. However, I think that if parallel code uses the built-in Clojure random number functions, there is probably a bottleneck in access to the RNG. With Criterium's bench function on an 8-core machine:
(def ones (doall (repeat 1000 1))) (bench (def _ (doall (map rand ones)))) ; 189 microseconds average time (bench (def _ (doall (pmap rand ones)))) ; 948 microseconds average time One solution that doesn't involve generating the numbers in advance is to create separate RNGs, as discussed in this thread <https://groups.google.com/forum/#!searchin/clojure/random/clojure/cRVS19PB06E/8FsmtsYx6SkJ>. This is a strategy that I am starting to explore. Related notes for anyone interested: As of Incanter 1.5.5 at least some functions such as sample are based on Clojure's bult-in rand, so they would have this problem as well. clojure.data.generators allows rebinding the RNG, and provides reservoir-sample and a replacement for the default rand-nth. The bigml/sampling <https://github.com/bigmlcom/sampling/tree/master/src/bigml/sampling> library provides sampling and random number functions with optional generation of a new RNG. -- 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.
