Oh also, the default Leiningen settings are optimized for reducing startup, not for speed. Use:
^:jvm-opts ^:replace ["-server"] ;; maybe also set max heap with "-Xmx1g" in there Or just don't use lein when perf testing. On Thursday, May 14, 2015 at 2:44:38 PM UTC-5, Alex Miller wrote: > > The major problem here is that you are using boxed math for everything > instead of primitives. > > 0) Switch to Clojure 1.7.0-beta3 - it's faster and some things below are > dependent on it for best performance. And use Java 1.8. > 1) Parse the lines you're reading directly into longs (Clojure focuses on > 64-bit primitives - longs and doubles) > 2) Put the longs first into a data structure that preserves the primitive > type. The two best options for that here are records (which can have > primitive fields) and arrays. I would create a Canvas defrecord with ^long > width and height and a Paper defrecord with all ^long fields for example. > 3) Store the papers in a vector (using transient to create it) > 4) I suspect visible-color and covered? could probably be tightened up > into a reduce over papers or a single loop-recur over papers - can't say I > totally get what's happening there. > 5) In visible-color-frequencies, you could use "update" instead of get + > transient assoc! on the acc map, but this is never going to be terribly > fast. Another option here would be to create an array with the max color > (you could track that while reading if it's not a well-known answer) and > bash the array. That can retain int or long counters and will be *way* > faster. > 6) You can use (set! *unchecked-math* :warn-on-boxed) to get faster math > (no overflow checks) and also issue warnings (added in 1.7) if you happened > to use boxed math by accident. > > > > On Thursday, May 14, 2015 at 3:02:42 AM UTC-5, Amith George wrote: >> >> I wrote the following code to solve this challenge - >> https://www.reddit.com/r/dailyprogrammer/comments/35s2ds/20150513_challenge_214_intermediate_pile_of_paper/ >> . >> >> Code - >> https://github.com/amithgeorge/reddit-dailyprogrammer-clojure/blob/56ce1dbb6a08e96150dc85934caecfeb68108a53/src/rdp/214_intermediate.clj >> >> I executed the -main function using `lein run 1`. >> >> Output >> >> ;; lein run 1 >> >> 0 12605919 >> 1 3578145 >> 2 15356894 >> 3 19134293 >> 4 2394558 >> 5 15030409 >> 6 6424953 >> 7 14893444 >> 8 1592254 >> 9 1914025 >> 10 7075106 >> "Elapsed time: 501168.972435 msecs" >> >> The code originally used an immutable hashmap, but I lost patience >> waiting for the computation to end. With mutable hashmap, it still takes >> around 8 mins. >> >> I wrote a C# version of the above code - >> https://gist.github.com/amithgeorge/766b8220f39d48221e58. It finishes >> under 40secs. The C# exe was built under Release mode and executed directly >> from the commandline. I expected the Clojure version to perform similarly. >> >> Any tips on what I am doing wrong? >> >> ----- >> Explanation of the code - Create a vector of all paper sheets, such that >> the sheet placed last is the first element of the vector and the last >> element is the canvas. To compute the frequency of each visible color - for >> each point in the canvas find the first sheet in the vector that covers the >> point. Store/increment its count in the hashmap. I understand there might >> be better more efficient ways to solve this, but currently I am interested >> in why the Clojure versions is so slow vis-a-vis the C# version. >> >> -- 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/d/optout.
