As with most microbenchmarks you're measuring the test more than the subject. In the above case the seq generation dominates.
Compare the following on my machine: user=> (time (doseq [x (range 100000)] (bit-shift-left x 1))) "Elapsed time: 3531.198 msecs" nil user=> (time (dotimes [x 100000] (bit-shift-left x 1))) "Elapsed time: 3.744 msecs" nil Beyond the seq issue there is a further (very small) penalty due to seqs working with objects, thus x from the range seq is a Long object, not a primitive long. You can see the implementation differences of shiftLeft here: http://github.com/clojure/clojure/blob/master/src/jvm/clojure/lang/Numbers.java#L425 On Sep 29, 11:19 pm, Mark Engelberg <mark.engelb...@gmail.com> wrote: > bitwise-and and bitwise-shift-right and bitwise-shift-left run more > than 50 times slower in clojure 1.3 alpha 1 versus clojure 1.2. Could > the 1.3 gurus please investigate this? > > Try something like this to see the difference: > (time (doseq [x (range 100000)] (bit-shift-left x 1))) > > This points to another issue with Clojure 1.3. I can't figure out how > to determine what is a primitive and what isn't. Are the values > produced by range primitives? Are the values produced by bitwise > operations primitive? How can I determine this? -- 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
