|Subject:||Primes() not mark i=composite for less work|
|Date:||Sat, 06 Nov 2010 07:40:41 +1100|
|From:||Kevin Ryde <firstname.lastname@example.org>|
Nosing around the code of Bit::Vector 7.1 BitVector_Primes(), as an optimization I wonder if the "j" loop doing BIT_VECTOR_CLR_BIT() can be skipped when i=composite. Eg. multiples of i=15 don't have to be marked as they're already covered by previous i=3 or i=5. Marking only primes found thus far is fairly usual I think. I suppose it'd be a check BIT_VECTOR_TST_BIT(addr,i) and ought to save a good bit of work.