sieve ( n -- #primes )

Vocabulary

benchmark.sieve

Inputs

n

an object

Outputs

#primes

an object

Definition

USING: bit-arrays kernel math math.functions ranges sequences ;

IN: benchmark.sieve

:: sieve ( n -- #primes )
    n dup odd? [ 1 + ] when
    2/ <bit-array> :> sieve t 0 sieve set-nth 3 n sqrt 2 <range> 
    [| i |
        i 2/ sieve nth [
            i sq n i 2 * <range>
            [| j | t j 2/ sieve set-nth ] each
        ] unless
    ] each sieve [ not ] count 1 + ;