sieve ( n -- sieve )

Vocabulary

math.primes.erato

Inputs

n	an integer

Outputs

sieve

a byte-array

Word description

Apply Eratostene sieve up to n. n must be greater than 1. Primality can then be tested using marked-prime?.

Definition

USING: kernel math math.functions math.primes.erato.private
ranges sequences ;

IN: math.primes.erato

:: sieve ( n -- sieve )
    n integer>fixnum-strict init-sieve :> sieve sieve
    upper-bound >fixnum :> upper 3 upper sqrt 2 <range> [| i |
        i sieve marked-unsafe?
        [ i upper sieve unmark-multiples ] when
    ] each sieve ;