Which version of Clojure are you using? (How to speed that up depends a lot of the version you use)
I would like to see a with a longer run. Optimised clojure is *asymptotically* nearly as fast as Java. With under 1000 calls I am not sure the JIT is called. Best, Nicolas. On Wed, Dec 22, 2010 at 5:52 PM, Rayne <disciplera...@gmail.com> wrote: > I have a piece of code, and I'd like to see how fast it can be. > > (defn count-num-chars [^String s] > (loop [s s acc 0] > (if (seq s) > (recur (rest s) (if (= (first s) \space) acc (inc acc))) > acc))) > > This is the fastest I've been able to get it. The function is very > simple. It takes a string and counts the number of non-space > characters inside of that string. > > I've been testing this code against a 460 non-space character string. > Here is the entire source, benchmarking and all: > > (def s (apply str (repeat 20 "This is a really long string"))) > > (defn count-num-chars [^String s] > (loop [s s acc 0] > (if (seq s) > (recur (rest s) (if (= (first s) \space) acc (inc acc))) > acc))) > > (println "Chars outputted:" (count-num-chars s)) > > (let [before (System/nanoTime)] > (dotimes [_ 1000] > (count-num-chars s)) > (let [after (System/nanoTime)] > (println "Time (in nanoseconds):" (/ (- after before) 1000.0)))) > > Running it gives me around 137343.295 nanoseconds. I've seen some Java > algorithms that could run at just under 3000 nanoseconds. > > Hide your children and hide your women; I want to see the direst, > nastiest, rawest, fastest possible implementation of this function. > > -- > 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 -- Sent from an IBM Model M, 15 August 1989. -- 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
