Clojure 1.3 のパフォーマンスに驚いた話
Clojureの今によると、 Clojure 1.3 からプリミティブ型による型注釈が可能になったようです。プリミティブ 型による型注釈は、最適化において最も重要な情報の一つですから、当然なが らその結果として、プリミティブな演算を伴う処理の高速化が期待できるわけ です。スライドでは、以下の fib 関数を例にとって、型注釈を与えた場合と 与えなかった場合とで、どれだけ実行速度が違うかを示しています。 ;; 型注釈なし (defn fib [n] (if (<= n 1) 1 (+ (fib (dec n)) (fib (- n 2))))) (time (fib 38)) ;=> Elapsed time: 4100.272 msecs ;; 型注釈あり (defn fib ^long [^long n] (if (<= n 1) 1 (+ (fib (dec n)) (fib (- n
Clojure performance tips « Occasionally sane
I originally wrote this in a Google Groups thread, but I figured it’s worth repeating here. Somebody posted a Java and Clojure snippet to the Clojure Google group and mentioned that the Java code was vastly faster than the Clojure code and he wondered if Clojure could get within reach of Java’s speed. In my own clj-starcraft project, I faced — and actually, still face — performance problems vis-à-
JVisualVM and Clojure
JVisualVM is a Java Virtual machine monitoring tool that allows you to see a live view of the Java memory, cpu and threads that are currently active. In this post, I'll look at how easy it is to profile Clojure code using JVisualVM. First step is to get jvisualvm installed. If you've got a recent JDK then it's already available in the bin directory of the JDK install. If not, then upgrade to the l
Paste number 93940: Compile-time type-checking multimethods
;;; COMPILE-TIME TYPE-CHECKING FOR MULTIMETHODS ;; These macros create a multimethod with compile-time type checking. ;; If the multimethod is called with literal arguments, the correct ;; method expansion will selected at compile-time and inlined. ;; ;; If the argument types cannot be determined at compile time, it will ;; fall back to a normal multimethod with run-time dispatch. ;; ;; This could
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