without looking at the code: ranges in scala have been optimized in i think 2.10 to be able to be inlineable completely when you iterate over them. at runtime, it *should* be equal to a simple while loop and a counter variable
Am 03.02.2013 14:28, schrieb Jules: > 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 > > <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. > > -- -- -- 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.
