I like tinkering with prime sieve algorithms.
Here's the fastest one I've come up with:
(defn bit-sieve [n]
(let [n (int n)]
"Returns a vector of all primes from 2 to n (not including n)"
(let [root (int (Math/round (Math/floor (Math/sqrt n]
(loop [i (int 3)
a (ja
On Sat, Nov 6, 2010 at 5:50 PM, Juha Arpiainen wrote:
> On Nov 6, 7:57 pm, Ken Wesson wrote:
>> (filter identity (map #(if %1 %2) (drop 2 sieve) (iterate inc 2)))
>
> Returning a lazy seq doesn't seem to make much sense here,
> especially since (map ... (drop 2 sieve)) holds onto the
>
On Nov 6, 7:57 pm, Ken Wesson wrote:
> Here's a Clojure sieve that works fine up to at least 50
> million and is reasonably fast (though the same algorithm implemented
> in Java is 10x faster even with the type hints and primitive
> arithmetic in the Clojure; not sure why).
>
> (defn primes-to [n]
On Sat, Nov 6, 2010 at 11:28 AM, thattommyhall wrote:
> Hey,
>
> I read http://www.cs.hmc.edu/~oneill/papers/Sieve-JFP.pdf a while ago
> and noticed you had referenced the paper and implemented the naive
> algorithm in contrib and thought I could chip in and do the sieve for
> you but get an error
