Rich has done a lot of work to make sure that when you are working with primitives, the JVM bytecode ends up being very similar to what Java would generate. See http://clojure.org/java_interop#toc36
Thanks, Stu On Thu, Mar 12, 2009 at 6:20 PM, Howard Lewis Ship <hls...@gmail.com> wrote: > > Well, at some point I'll open up the code and check. Though I'll be > overly tempted to write some comments, fix the indentation and write > some tests if I do! > > On Thu, Mar 12, 2009 at 2:36 PM, Jarkko Oranen <chous...@gmail.com> wrote: > > > > > > On Mar 12, 11:15 pm, Howard Lewis Ship <hls...@gmail.com> wrote: > >> I have to wonder a bit about the ability to optimize. Everything > >> boils down to one of the seven or so basic forms. That's a lot of > >> function calls to do even small things, like adding numbers. You might > >> think that simple math would be optimized and inlined, but it isn't: > >> > >> Clojure > >> user=> (doc +) > >> ------------------------- > >> clojure.core/+ > >> ([] [x] [x y] [x y & more]) > >> Returns the sum of nums. (+) returns 0. > >> nil > >> user=> (ns clojure.core) > >> #<Namespace clojure.core> > >> clojure.core=> (defn + [x y] (* x y)) > >> #'clojure.core/+ > >> clojure.core=> (+ 3 5) > >> 15 > >> clojure.core=> > >> > >> This implies, to me, that Clojure is doing a full functional call, > >> with dynamic lookup via the namespace, even for +. > > > > I think this is mistaken. Sure, for (+ foo bar) calls in the repl > > Clojure will do a full lookup, but if you have addition in a tight > > loop, the JVM should notice this and optimise it further. (I think > > Clojure also does some kind of caching.) You can also use type casts > > to make clojure use primitive instead of boxed math, bringing > > performance very close to Java. > > > > Now, it's probably true that the most straightforward Clojure > > implementation of an algorithm is likely not quite as fast as the Java > > equivalent, with a few tricks, you can often get pretty close. > > > > I don't have very in-depth knowledge of how Clojure handles these > > performance issues, but I believe your assumption is overly > > pessimistic. :) > > > > -- > > Jarkko > > > > > > > > > -- > Howard M. Lewis Ship > > Creator Apache Tapestry and Apache HiveMind > > > > --~--~---------~--~----~------------~-------~--~----~ 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 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 -~----------~----~----~----~------~----~------~--~---
