The Scala version is probably faster because it uses a range (1 to top) which is represented as a pair of integers (the start and endpoint). Perhaps the JVM can even eliminate that completely with escape analysis. The Java version is repeatedly filling an ArrayList with the numbers in that range.
On Sunday, February 3, 2013 12:19:51 PM UTC+1, Casper Clausen wrote: > > Given that I don't know much about how scala does optimizations, I find > the question of why the scala version is faster than the Java version even > more interesting. > > It seems to me that in Scala, the list (don't know the actual data type > which is created) of 1 to 20 is created each time isDivisibleByAll is > called which (probably?) creates some overhead. > > The Java version doesn't create the list for each check, but it uses an > ArrayList where it could use an array and Integer where it could use int - > shenedu makes that optimization in the buttom, but it only improves about > half a second according to him. > > So what's going on the Scala version? > > On Sunday, February 3, 2013 3:28:09 AM UTC+1, Alexandros Bantis wrote: >> >> Hello all. I'm working through the Project Euler problems in Java, >> Scala, & Clojure (trying to learn all three?!?). I notice that for one >> particular problem, I use--more or less--a similar algorithm for all >> three, but the clojure code runs about 20-30 times slower than the >> java/scala versions. Does anyone have any idea why this might be? It >> strikes me that it might have something to do with every? but I don't >> know because I'm a newbie with Clojure. >> >> >> http://stackoverflow.com/questions/14668272/what-can-i-do-to-speed-up-this-code >> >> >> thanks, >> >> alex >> > -- -- 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 --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
