With type hints your implementation should run faster:
(defn fib ^long [^long n]
(if (< n 2)
n
(+ (fib (- n 2)) (fib (- n 1)))))
What does your Java code look like? Is it also recursive?
On 13 August 2017 at 10:54, Daniel Gerlach <daniel.gerlach1...@gmail.com>
wrote:
> Hey,
>
> out of curiosity i did some benchmarking on my Macbook Pro 13 i5 2,7 GHz.
>
> I chose a simple naive fibonacci implementation as a candidate
> (i know that is not a good comparison value for real-world cases)
>
> The implementation looks like this:
>
> (defn fib [n]
> (if (< n 2)
> n
> (+ (fib (- n 2)) (fib (- n 1)))))
>
>
>
> The results are a little bit surprising.
>
> The average time for fib(32) in Clojure was ~ 500ms
> The same algorithm in Java takes ~ 15 ms to finish.
> That means Clojure it's ~30x slower than Java for this special case.
>
> I also "warmed up" the JVM in both cases. For Clojure i used "criterium".
>
>
> Can somebody explain? Do i do something wrong? Are there any optimization
> <http://www.dict.cc/englisch-deutsch/optimization.html>s possible, e.g.
> type hints etc. ?
> Does Clojure has problems with recursive functions?
>
>
> Greetings
>
> Daniel Gerlach
>
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