# Finding primes using a primes map with Haskell and Hugs98

**Colin.Runciman@cs.york.ac.uk
**
Colin.Runciman@cs.york.ac.uk

*Wed, 20 Dec 2000 14:49:30 GMT*

>* There are numerous ways of optimising sieving for primes, none of which
*>* have much to do with this list. For example, two suggestions:
*>* (1) for each k modulo 2*3*5*7, if k is divisible by 2/3/5 or 7, ignore, otherwise
*>* sieve separately for this k on higher primes. (Or you might use products of
*>* more or less primes, depending on memory and how high you were going.)
*>* ...
*>* I don't really see why any of this has anything to do with Haskell though.
*>* When it comes to seriously icky bit-twiddling algorithms I don't think Haskell
*>* has much to offer over C, especially as you'd have to make everything unboxed if
*>* you want comparable speed.
*
Forgive the self-reference, but the following short article is
all about this very topic:
C. Runciman,
Lazy wheel sieves and spirals of primes,
Journal of Functional Programming, v7, n2, pp219--226,
March 1997.