In addition, right now his Clojure code isn't directly analogous to his Java code. If he used an array of bytes instead of integers, he wouldn't need the bit-masking.
Getting this to work revealed a big surprise to me. Java has only signed integer types: byte, short, int and long. Clojure reads 0xFF as the _signed_ integer 255. I would expect it to be -1. For example, (every? #(= % (bit-and -1 %)) (range -128 128)) evaluates to true. This looks like a genuine bug. -Per On Tue, Mar 23, 2010 at 7:08 PM, Konrad Hinsen <konrad.hin...@fastmail.net> wrote: > On 23.03.2010, at 08:55, Raph wrote: > >> I have tried various hinting methods, but I cannot increase the speed. >> What can I do to make the clojure operations as fast as the native >> Java operations? > > Get rid of the reduce and unroll the bit-or computations instead: > > (defn arr-to-int [#^ints x] > (bit-or (bit-shift-left (bit-and 0xFF (aget x 0)) 24) > (bit-or (bit-shift-left (bit-and 0xFF (aget x 1)) 16) > (bit-or (bit-shift-left (bit-and 0xFF (aget x 2)) 8) > (bit-and 0xFF (aget x 3)))))) > > That makes for a factor 3.3 on my machine. > > Konrad. > > -- > 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 > > To unsubscribe from this group, send email to > clojure+unsubscribegooglegroups.com or reply to this email with the words > "REMOVE ME" as the subject. > -- 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 To unsubscribe from this group, send email to clojure+unsubscribegooglegroups.com or reply to this email with the words "REMOVE ME" as the subject.
