You could also memoize.

Sent from my iPad

> On Aug 13, 2017, at 7:27 AM, James Reeves <ja...@booleanknot.com> wrote:
> 
> 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 optimizations 
>> possible, e.g. type hints etc. ? 
>> Does Clojure has problems with recursive functions?
>> 
>> 
>> Greetings
>> 
>> Daniel Gerlach
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> 
> 
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> James Reeves
> booleanknot.com
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