[Haskell-cafe] Looking for the fastest Haskell primes
algorithm
ajb at spamcop.net
ajb at spamcop.net
Thu Apr 16 22:16:01 EDT 2009
G'day all.
Quoting Eugene Kirpichov <ekirpichov at gmail.com>:
> I'd suggest also
>
> primesFrom :: Integer -> [Integer]
This:
primes :: [Integer]
isn't as useful as you might think for a library, because it must, by
definition, leak an uncontrolled amount of memory. This:
primesUpTo :: Integer -> [Integer]
is a better interface in that respect.
For the number theory library, I went overboard with a bunch of type
classes. I don't have the code handy, but this was the sort of thing:
class TestableProperty s a | s -> a where
is :: s -> a -> Bool
data Prime = Prime
class TestableProperty Prime Integer where
is Prime n = {- ... -}
Then you could add instances for Fibonacci or whatever you wanted.
Cheers,
Andrew Bromage
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