> > > The first benchmark is the slowest of all because it's: > - realizing the nums lazy sequence > - realizing the vpairs lazy sequence > - destructuring a vector > - creating and realizing a lazy sequene of record types > - only then benchmarking the reduce operation.
I was under the impression that the call to "apply list" would realize the lazy sequences beforehand. On Thursday, 12 May 2016 13:09:57 UTC-7, Nicola Mometto wrote: > > Those benchmarks are flawed and you're not testing what you think you are. > > The first benchmark is the slowest of all because it's: > - realizing the nums lazy sequence > - realizing the vpairs lazy sequence > - destructuring a vector > - creating and realizing a lazy sequene of record types > - only then benchmarking the reduce operation. > > In the second benchmark you're still benchmarking the destructuring of > vector pairs and the creation and realization of a lazy sequence of types > The third benchmark is like the second in that you're creating and > realizing a lazy sequence but it's slightly faster than the second one > because you're not including destructuring in the mix > The last benchmark is the fastest of all because you're just iterating > over an already realized sequence. > > In no benchmark you're actually using any primitive types, you're always > using boxed Doubles > > > On 12 May 2016, at 20:58, JvJ <kfjwh...@gmail.com <javascript:>> wrote: > > > > I've been doing some performance tests on various floating point > operations. In particular, I wanted to check what would be the fastest way > to implement a 2-d floating point vector in clojure. > > > > Here's my tests: > > > > ;;; V+ Tests > > ;;; Implementing floating-point vectors as: > > ;;; structs, deftype, vector > > (defrecord v2r > > [^Double x ^Double y]) > > > > (defn rv+ > > [^v2r v1 ^v2r v2] > > (v2r. (+ (.x v1) (.x v2)) > > (+ (.y v1) (.y v2)))) > > > > (deftype v2t > > [^Double x ^Double y]) > > > > (defn tv+ > > [^v2t v1 ^v2t v2] > > (v2t. (+ (.x v1) (.x v2)) > > (+ (.y v1) (.y v2)))) > > > > (defn vv+ > > [v1 v2] > > (mapv + v1 v2)) > > > > > > (defn testvecs > > "Tests the vector add operations by reducing a > > random list by each of the v+ operations on > > identical sets of random vectors" > > [n] > > (let [nums (repeatedly (* 2 n) rand) > > vpairs (partition 2 nums) > > v2r-list (apply list (map (fn [[x y]] (v2r. x y)) vpairs)) > > v2t-list (apply list (map (fn [[x y]] (v2t. x y)) vpairs)) > > v2v-list (apply list (map vec vpairs))] > > (println "V2 Record:") > > (bench (reduce rv+ v2r-list)) > > (println "V2 Type:") > > (bench (reduce tv+ v2t-list)) > > (println "V2 Vector:") > > (bench (reduce vv+ v2v-list)) > > (println "Just Doubles:") > > (bench (reduce + nums)))) > > > > > > Here's my output: > > > > V2 Record: > > Evaluation count : 420 in 60 samples of 7 calls. > > Execution time mean : 164.379725 ms > > Execution time std-deviation : 4.478128 ms > > Execution time lower quantile : 149.546749 ms ( 2.5%) > > Execution time upper quantile : 172.317132 ms (97.5%) > > Overhead used : 1.873322 ns > > > > Found 8 outliers in 60 samples (13.3333 %) > > low-severe 4 (6.6667 %) > > low-mild 3 (5.0000 %) > > high-mild 1 (1.6667 %) > > Variance from outliers : 14.2105 % Variance is moderately inflated by > outliers > > V2 Type: > > Evaluation count : 1860 in 60 samples of 31 calls. > > Execution time mean : 32.238857 ms > > Execution time std-deviation : 2.331682 ms > > Execution time lower quantile : 26.769206 ms ( 2.5%) > > Execution time upper quantile : 35.318368 ms (97.5%) > > Overhead used : 1.873322 ns > > > > Found 8 outliers in 60 samples (13.3333 %) > > low-severe 5 (8.3333 %) > > low-mild 3 (5.0000 %) > > Variance from outliers : 53.4940 % Variance is severely inflated by > outliers > > V2 Vector: > > Evaluation count : 2040 in 60 samples of 34 calls. > > Execution time mean : 30.175015 ms > > Execution time std-deviation : 3.870306 ms > > Execution time lower quantile : 21.877116 ms ( 2.5%) > > Execution time upper quantile : 37.668717 ms (97.5%) > > Overhead used : 1.873322 ns > > > > Found 10 outliers in 60 samples (16.6667 %) > > low-severe 5 (8.3333 %) > > low-mild 2 (3.3333 %) > > high-mild 3 (5.0000 %) > > Variance from outliers : 78.9869 % Variance is severely inflated by > outliers > > Just Doubles: > > Evaluation count : 20640 in 60 samples of 344 calls. > > Execution time mean : 4.309871 ms > > Execution time std-deviation : 537.444033 µs > > Execution time lower quantile : 2.389294 ms ( 2.5%) > > Execution time upper quantile : 4.716009 ms (97.5%) > > Overhead used : 1.873322 ns > > > > Found 8 outliers in 60 samples (13.3333 %) > > low-severe 5 (8.3333 %) > > low-mild 2 (3.3333 %) > > high-mild 1 (1.6667 %) > > Variance from outliers : 78.9282 % Variance is severely inflated by > outliers > > > > > > The performance is amazingly better when using primitive doubles, even > though all operations are doing effectively the same thing: 20000 floating > point add operations. I assume that the overhead of allocating a new > vector2 object is responsible for the decline in performance. > > > > Did I use type hints correctly? Is there a way to keep the "x and y" > vector abstraction and still get something approaching primitive > performance? > > > > -- > > You received this message because you are subscribed to the Google > > Groups "Clojure" group. > > To post to this group, send email to clo...@googlegroups.com > <javascript:> > > Note that posts from new members are moderated - please be patient with > your first post. > > To unsubscribe from this group, send email to > > clojure+u...@googlegroups.com <javascript:> > > 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+u...@googlegroups.com <javascript:>. > > For more options, visit https://groups.google.com/d/optout. > > -- You received this message because you are subscribed to the Google Groups "Clojure" group. 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