On 15/07/07, Donald Bruce Stewart
dons:
dons:
hughperkins:
Hey, I just realized I can shave off another 30% in C# ;-) So now the timings become:
Ok. So do the same thing to the Haskell program. The compilers should produce pretty much identical assembly.
Oh, and I forgot you count up by two now. Here's the Haskell transliteration (again).
Oh, also, I was using the wrong brackets in the last program! Stick with me, because this makes the program go at least 100x faster.
First, we'll move the pureSieve into a library module:
{-# OPTIONS -O2 -optc-O -fbang-patterns #-}
module Primes (pureSieve) where
import Control.Monad.ST import Data.Array.ST import Data.Array.Base import System import Control.Monad import Data.Bits
pureSieve :: Int -> Int pureSieve n = runST ( sieve n )
sieve n = do a <- newArray (3,n) True :: ST s (STUArray s Int Bool) let cutoff = truncate (sqrt (fromIntegral n)) + 1 go a n cutoff 3 1
go !a !m cutoff !n !c | n >= m = return c | otherwise = do e <- unsafeRead a n if e then if n < cutoff then let loop !j | j < m = do x <- unsafeRead a j when x $ unsafeWrite a j False loop (j+n)
| otherwise = go a m cutoff (n+2) (c+1)
in loop ( if n < 46340 then n * n else n `shiftL` 1) else go a m cutoff (n+2) (c+1)
else go a m cutoff (n+2) c
And now just a module to call it:
{-# OPTIONS -fth #-}
import Primes
main = print $( let x = pureSieve 10000000 in [| x |] )
Pretty simple to compile and run this now:
$ ghc --make -o primes Main.hs $ time ./primes 664579 ./primes 0.00s user 0.01s system 228% cpu 0.003 total
Oh! Much faster. Looks like Haskell is 100x faster than C#. Who gets fired? :)
Oooh, I love it! -- Sebastian Sylvan +44(0)7857-300802 UIN: 44640862