I ported Mikera's benchmark to Clojure using my patch https://gist.github.com/cgrand/6595939 The ratio between time-float and time-double (0.632) is very similar to the ratio between timeFloat and timeDouble Mikera reported (0.618)
On Tue, Sep 17, 2013 at 1:25 PM, Christophe Grand <christo...@cgrand.net>wrote: > Here is the mundane patch I described earlier: > https://github.com/cgrand/clojure/commit/4c202ad9757ce47ac9e669847c0e5bf68785e2d6 > > It adds four functions (add-, multiply-, divide- and subtract-float), > backs them with their corresponding bytecodes and enhance the conversion > emitted when going from long/int to double/float. > > Please give it a try. > > It doesn't help with functions taking primitive but it's another problem. > > Christophe > > On Mon, Sep 16, 2013 at 7:03 PM, James Reeves <ja...@booleanknot.com>wrote: > >> >> >> >> On 16 September 2013 09:03, Mikera <mike.r.anderson...@gmail.com> wrote: >> >>> >>> Obviously this is just a microbenchmark, but it fits my general >>> experience that floats are a reasonable bit faster than doubles, typically >>> 20-100% (doubles are closer when it is pure number crunching since 64-bit >>> CPUs are actually pretty good at doubles, floats have a bigger advantage >>> when you are manipulating a lot of data points and hence memory bandwidth >>> matters more) >>> >>> Code here for those interested: >>> src/test/java/mikera/vectorz/performance/FloatVsDoubleBenchmark.java >>> >> >> That's a pretty interesting result. I ran some tests of my own, based on >> your code, as I wondered whether or not the time to instantiate the array >> of doubles was biasing the test. My goal was to see whether or not I'd get >> a similar result running an array of floats through a method that processed >> doubles. (See: https://gist.github.com/weavejester/6583367) >> >> It turns out that I get a similar result. Passing floats to a method that >> takes doubles slows things down by a similar amount, unless I've somehow >> botched up the test. Considering that converting between single and double >> precision should be pretty cheap on the CPU, I'm surprised at the >> difference. >> >> This somewhat changes my view on things. It doesn't affect me in >> practice, but I can see how someone might be frustrated by having to drop >> down to Java to achieve performance for floating point calculations. >> >> - James >> >> -- >> -- >> 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. >> > > > > -- > On Clojure http://clj-me.cgrand.net/ > Clojure Programming http://clojurebook.com > Training, Consulting & Contracting http://lambdanext.eu/ > -- On Clojure http://clj-me.cgrand.net/ Clojure Programming http://clojurebook.com Training, Consulting & Contracting http://lambdanext.eu/ -- -- 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.
