"One thing you need to do is define what you mean exactly when you say "Java vs Clojure." "
Like I said, I didn't want to get too focused on this particular example. Is there code where I could run in Clojure and where I could run in Java that would end up with the same result. And then I could see the differences in performance. Also is there an example where Clojure code is comparable. For example, lets say the Euler problem number 1 wants you want to return a result of 123. The end result is 123, if I write code in Java and then in Clojure, I want to see the runtimes of the different versions. On Jul 27, 1:34 pm, Aaron Cohen <remled...@gmail.com> wrote: > One thing you need to do is define what you mean exactly when you say "Java > vs Clojure." > In your example you are comparing clojure code vs java code but you are also > comparing clojure data structures (PersistentMap) with traditional Java data > structures (HashMap). I'm not sure you meant to conflate the two. > > Also, there have been plenty of threads that start off comparing java and > clojure performance and eventually end up at near-equivalent performance > after using type hints/coercion/etc. It has become something of a FAQ. I'd > start > with:http://groups.google.com/groups/search?q=group:clojure+performance&qt... > <http://groups.google.com/groups/search?q=group:clojure+performance&qt...> > -- Aaron > > On Mon, Jul 27, 2009 at 1:06 PM, BerlinBrown <berlin.br...@gmail.com> wrote: > > > I was coming up with some performance tests for Clojure, going back > > and forth between different JVM languages (JRuby, Scala) and mainly > > looking at pure Java code. So far I have found that clojure is about > > 5-10 times as slow as comparable code in Clojure. Of course this is > > before any optimizations. > > > Here is my question, do you have any code both Clojure and Java where > > there is a one to one match between code where Clojure runs as fast as > > Java. It could be anything. > > > Here is one example: > > This is code from clojure/contrib to convert a list of data into a > > frequency count map. Pretty standard stuff. > > > (defn frequencies > > "Returns a map from distinct items in coll to the number of times > > they appear." > > [coll] > > ;;;;;;;;; > > (reduce (fn [counts x] > > (assoc counts x (inc (get counts x 0)))) > > {} coll)) > > > (dotimes [x 4] > > (println "i: " (int (Math/pow 10.0 x))) > > (time > > (dotimes [_ (int (Math/pow 10.0 x))] > > (let [a (for [_ (range 1000)] (random-string 3))] > > (frequencies a))))) > > > ---------------------- > > > public static Map frequencies(final List list) { > > final Map map = new HashMap(); > > // Simple Box and then unbox the count as the value for this > > map // > > for (Iterator it = list.iterator(); it.hasNext(); ) { > > final Object o = it.next(); > > final String s = o.toString(); > > Integer prev = (Integer) map.get(s); > > if (prev == null) { > > // Put a new value on th map > > final Integer count = ONE; > > map.put(s, count); > > } else { > > final Integer inc = new Integer(prev.intValue() + 1); > > map.put(s, inc); > > } // End of the if - else // > > } > > return map; > > } > > ---------------------- > > > Clojure Results (same machine 1.5 JDK) > > > i: 1 > > "Elapsed time: 51.657859 msecs" > > i: 10 > > "Elapsed time: 212.568221 msecs" > > i: 100 > > "Elapsed time: 1623.107702 msecs" > > i: 1000 > > "Elapsed time: 16356.185166 msecs" > > (used:2M/0M [2M,63M ]) > > Done > > Performing simple garbage collection cooldown > > (used:2M/0M [2M,63M ]) > > (used:2M/0M [2M,63M ]) > > > ------------- > > > Here are the Java results. > > > 14.631606999999999 ms > > 4.828342999999999 ms > > i: 10 > > Elapsed time: 9.803628 msecs > > i: 100 > > Elapsed time: 97.562451 msecs > > i: 1000 > > Elapsed time: 972.775771 msecs > > (used:1M/0M [1M,63M ]) > > (used:1M/0M [1M,63M ]) > > (used:1M/0M [1M,63M ]) > > > NOTE:!!! This is just one example. All my other examples, ended up > > the same way. I hope you don't nitpick this one. > > > I know we should take performance tests with a grain a salt. But at > > the same time, I feel we should at least try to measure the speed of > > some of our code. I haven't found many speed tests out there on > > clojure. --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
